CN118621287A - A plasma window in-situ ion implantation modification method and system for hard and brittle material processing - Google Patents

Abstract

The invention discloses a plasma window-based in-situ ion implantation modification method and system applied to processing of hard and brittle materials, and belongs to the technical field of ultra-precise processing. Comprises an ion acceleration unit for generating and controlling an ion beam which is subjected to parallel motion, a plasma window unit for outputting the ion beam to the atmosphere after passing through confined plasma, and an electrostatic lens unit for realizing ion beam focusing; the invention can realize ion transmission in the atmospheric environment, and is suitable for ion implantation modification, polishing modification and other functions in the atmospheric environment. The high vacuum environment is avoided, the equipment and the operation flow are greatly simplified, and the cost is reduced. In addition, the ion implantation modification is generally more convenient and quick in the atmospheric environment, a complex vacuum system is not needed, and the equipment is started and closed for a short time. The ion implantation can be performed in a specific region of the material, so that the local characteristics of the material can be selectively improved, and the method has extremely high application prospect.

Description

A plasma window based in-situ ion implantation modification method and system for hard and brittle material processing

Technical Field

The invention belongs to the technical field of ultra-precision machining, and in particular relates to a plasma window-based in-situ ion implantation modification method and system for machining hard and brittle materials.

Background Art

Sapphire, yttrium aluminum garnet (YAG), spinel and other hard and brittle materials have been widely used in many fields due to their excellent physical, chemical and optical properties. For example, sapphire is not only a gemstone, but also widely used in military aviation fields represented by perspective windows, optical components represented by satellites and high-end camera lenses, etc. because of its hardness second only to diamond, high melting point, good thermal conductivity, chemical stability and UV resistance. However, sapphire has extremely high hardness, and ultimately uses chemical mechanical polishing to obtain extremely high surface quality. This processing process is time-consuming and difficult to achieve industrial production. However, the traditional diamond cutting method will cause the tool to break and the surface quality of the processed surface is poor. Using ion implantation modification to reduce the hardness of sapphire materials can greatly improve the machinability of sapphire, achieve high-quality processing of sapphire, and provide the service life of the tool. High-energy ion beam implantation is a widely used material modification method that can effectively improve the processing performance of materials. Due to the vacuum environment requirements, the current ion beam implantation device can only modify the workpiece for a long time in a non-situ manner before processing, and the process is complicated. At the same time, it is impossible to control the dose, energy and depth of the implanted ions very accurately according to the processing position in a vacuum environment. In-situ ion implantation modification can achieve complex surface tracking without the need for masks, simplify the process flow and improve the overall processing efficiency. In addition, the ion implantation technology in a vacuum environment cannot adjust the size of the processing area in real time according to the size of the processing area.

Summary of the invention

The technical problem solved by the present invention is to provide a method and system for in-situ ion implantation modification based on plasma window, which is applied to the processing of hard and brittle materials, and which uses plasma window technology to realize the extraction of ion beam from a vacuum environment, uses an electrostatic lens to realize the focusing of ion beam, and can adjust the ion beam implantation area. Finally, the ion beam implantation modification in the atmospheric environment is realized, and the method and system are applied to the processing of hard and brittle materials.

Technical solution: In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

An in-situ ion implantation modification method based on a plasma window for use in hard and brittle material processing, wherein an ion source generates an ion beam, the ion beam is led out of a vacuum environment through a plasma window, an electrostatic lens is used to focus the ion beam, the ion beam implantation area is adjusted, and finally ion beam implantation modification is achieved in an atmospheric environment.

Furthermore, the method specifically includes the following steps:

S1: Generate an ion beam and control the ion beam to move in parallel;

S2: The parallel moving ion beam enters the plasma window. The plasma window obtains a confined high-density plasma by means of tip discharge and inductive coupling under the gas. The ion beam passes through the confined plasma and is output to the atmospheric environment.

S3: After the ion beam output from the plasma window is focused, it acts on the surface of the workpiece to adjust the ion beam implantation area, and finally realizes ion beam implantation modification in the atmospheric environment.

Furthermore, in step S1, the ion source generates an ion beam, and changes the beam intensity and energy by controlling process parameters; then, the ion beam output is realized with the help of an acceleration voltage, and an alternating magnetic field is generated by a scanning electromagnetic coil to deflect the ion beam back and forth, so that the beam is straightened to form a fan-shaped belt-shaped ion beam; then, the collimation electromagnetic coil focuses the divergent ion beam into a uniform ion beam to obtain a parallel moving ion beam.

Furthermore, in step S2, the tip discharge unit performs tip discharge under the action of a strong electric field to form plasma, and an AC electric field is applied to the inductor coil. The magnetic field generated by the discharge of the inductor coil constrains the high-density plasma to ensure the stability of the plasma, and then the ion beam is output to the atmospheric environment after being confined by the plasma.

Furthermore, in step S3, the ion beam output from the plasma window first passes through two-stage electrostatic lens elements to achieve two-stage focusing of the ion beam, control the diameter of the output ion beam, and reduce the emission angle of the ion beam again; then, the angle of the deflection optical axis of the ion beam is changed through the upper and lower deflection electrodes, and finally the ion beam is focused again through the nozzle, and the beam spot diameter of the ion beam is reduced before being output to act on the surface of the workpiece.

A plasma window in-situ ion implantation modification system for hard and brittle material processing for realizing the above modification method, comprising an ion acceleration unit, a plasma window unit and an electrostatic lens unit;

The ion acceleration unit is used to generate and control the parallel motion of the ion beam;

The plasma window unit is used to output the ion beam to the atmospheric environment after passing through the confined plasma;

The electrostatic lens unit is used to achieve focusing of the ion beam.

Furthermore, the ion acceleration unit includes an ion source, an accelerator, a focusing lens, a scanning electromagnetic coil and a collimating electromagnetic coil; the ion source generates ions and draws out the ions through an electric field, the scanning electromagnetic coil realizes a straight beam to form a fan-shaped belt-shaped ion beam, and the collimating electromagnetic coil focuses the ion beam to obtain a parallel moving ion beam.

Furthermore, the plasma window unit includes a tip discharge unit, a quartz glass tube, an inductor coil, and a copper plate. The tip discharge unit is connected to the quartz glass tube. The quartz glass tube is arranged along the central axis. A plurality of copper plates are arranged at intervals on the outer periphery of the quartz glass tube. An inductor coil wrapped around the outer periphery of the quartz glass tube is arranged between the copper plates.

Furthermore, ceramic insulating material is filled between the copper plate and the inductor coil, and a first cooling pipeline is arranged in the copper plate to cool the copper plate.

Furthermore, the electrostatic lens unit mainly includes two adjacently arranged electrostatic lens elements, two coaxially arranged deflection electrodes, and a nozzle for realizing ion beam refocusing.

Beneficial effects: Compared with the prior art, the present invention has the following advantages:

The plasma window-based in-situ ion implantation modification method and system for hard and brittle material processing of the present invention uses plasma window technology to realize the derivation of the vacuum environment of the ion beam, uses an electrostatic lens to realize the focusing of the ion beam, and can adjust the ion beam implantation area. This technology can realize ion beam implantation modification in an atmospheric environment, reduce the process steps in the sapphire implantation modification process, improve the sapphire processing efficiency, and has a very high application prospect.

The plasma window-based in-situ ion implantation modification system for hard and brittle material processing of the present invention can realize ion transmission in an atmospheric environment, and is suitable for ion implantation modification, polishing and shaping and other functions in an atmospheric environment. It avoids high vacuum environments, greatly simplifies equipment and operating procedures, and reduces costs. In addition, ion implantation modification in an atmospheric environment is usually more convenient and faster, does not require a complex vacuum system, and the equipment startup and shutdown time is short. Since a high-energy-consuming vacuum pump is not required, this method is usually more environmentally friendly and has lower energy consumption. Ion implantation can be performed in specific areas of the material, so that the local properties of the material can be selectively improved. The modification effect of the material surface can be accurately adjusted by controlling the type, energy, dosage and injection time of the ions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a plasma window in-situ ion implantation modification system for hard and brittle material processing;

FIG2 is a schematic diagram of an application of a plasma window in-situ ion implantation modification system for hard and brittle material processing;

FIG3 is a schematic diagram of the three-dimensional structure of a plasma window unit;

FIG4 is a schematic cross-sectional view of a plasma window unit;

FIG5 is a schematic cross-sectional view of a tip discharge unit;

FIG6 (a) is a schematic diagram of the structure of an electrostatic lens unit, and (b) is a schematic diagram of a deflection electrode;

FIG. 7 is a flow chart of a plasma window-based in-situ ion implantation modification method for hard and brittle material processing.

DETAILED DESCRIPTION

The present invention is further explained below in conjunction with specific examples. The examples are implemented based on the technical solution of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Method for verifying the reliability of equipment

As shown in FIG. 1 , the plasma window-based in-situ ion implantation modification system for hard and brittle material processing of the present invention comprises an ion acceleration unit 1 , a plasma window unit 2 and an electrostatic lens unit 3 .

As shown in Figure 2, the main components of the ion acceleration unit 1 include ion source 11, accelerator 12, focusing lens 13, scanning electromagnetic coil 14, collimating electromagnetic coil 15, neutral beam deflector, X/Y scanning platform and other components. Among them, the ion source applies an ion source to generate various ions, and forms an ion beam by electric field extraction. Apply a voltage of more than 100kv to the accelerator so that the accelerator generates a high-voltage electrostatic field to accelerate the ion beam. The neutral beam deflector uses an offset electrode and an offset angle to separate neutral atoms. The scanning electromagnetic coil uses an electromagnetic coil to generate an alternating magnetic field, deflect the ion beam back and forth, realize the beam into a straight line, and form a fan-shaped ribbon-shaped ion beam, and the ions are the divergent movement direction. The collimating electromagnetic coil can focus the divergent ion beam into a uniform ion beam to obtain a parallel motion ion beam. As shown in Figures 3 and 4, the plasma window unit 2 includes a connecting portion 21, a tip discharge unit 22, a quartz glass tube 23, an inductor 24, a copper plate 25, a first cooling pipeline and a ground electrode 26. The quartz glass tube 23 is arranged along the central axis, and a plurality of copper plates 25 are evenly spaced through the outer periphery of the quartz glass tube 23 . An inductor coil 24 wrapped around the outer periphery of the quartz glass tube 23 is arranged between the copper plates 25 , and a first cooling pipeline is arranged in the copper plates 25 to cool the copper plates 25 .

As shown in FIG5 , the tip discharge unit 22 is used to generate plasma. The tip discharge unit 22 is fixed to the outer side of the frontmost copper plate 25 through a flange. The quartz glass tube 23 has an opening. The tip discharge unit 22 is connected to the inside of the quartz glass tube 23 through the channel in the flange and the opening of the quartz glass tube 23. The tip discharge unit 22 includes a high voltage anode power supply (not shown in the figure), a tip discharge tungsten needle 221, a cathode grounding, and a cooling water channel 223. The tip discharge tungsten needle 221 is designed as a hollow structure. The internal channel is used as a channel for transmitting gas. The rear end of the tip discharge tungsten needle 221 is a gas inlet 224 connected to a gas source of an inert gas. The front end of the tip discharge tungsten needle 221 is a gas outlet 225. The gas outlet 225 is the tip of the tip discharge tungsten needle and is connected to the inside of the quartz glass tube 23 through the opening of the quartz glass tube 23. A cooling water channel 223 is provided on the outer periphery of the tip discharge tungsten needle 221 to cool the tungsten needle to prevent the plasma from being generated due to excessive temperature. The cooling water channel 223 connects the cooling water inlet 226 and the cooling water outlet 227. The process gas for plasma discharge is passed through the tip discharge tungsten needle 222. Generally, an inert gas such as helium, argon, or neon is selected to maintain the internal gas pressure stable and ensure the stability of plasma generation, thereby avoiding the influence of the gas in the plasma window on the output quality of the ion beam.

Three tip discharge units 22 are evenly arranged to evenly deliver inert gas into the quartz glass tube 23 to ensure that the plasma can isolate the ion beam from the atmospheric environment stably and with high quality.

As shown in FIGS. 3 and 4 , the inductor 24 is located between two copper plates 25 and wrapped around the quartz glass tube 23 . An alternating electric field of 13.56 MHz is applied to the inductor 24 to ensure the stability of the plasma.

Ceramic insulating material 29 is filled between the copper plate 25 and the inductor coil 24, or insulating material is wrapped around the outer periphery of the copper plate 25, so that the copper plate 25 is insulated and isolated from the copper coil to avoid interference between the electric field of the tip discharge and the inductor discharge. The spacing of the copper plates 25 is set to reserve installation space for the inductor coil 24. Due to the high thermal conductivity of copper, the main function of the copper plate is to dissipate heat for the quartz glass tube 23. In order to further improve the heat dissipation effect, a first cooling pipeline is set in the copper plate 25. The connection of the first cooling pipeline leads to the external cooling water inlet 27 and cooling water outlet 28. As shown in the figure, the cooling water circulation prevents the copper plate 25 from generating a high temperature environment, resulting in oxidation of the copper plate and changes in the electrical conductivity of the copper plate, which affects the stability of the plasma.

The quartz glass tube 23 is a channel for plasma generation and is used to constrain the shape of the plasma column. At the same time, the plasma column can realize the output of ions. A connecting portion 21 is provided at the front end of the quartz glass tube 23, and the connecting portion 21 is used to connect the ion acceleration unit 1 and the quartz glass tube 23. A valve is also provided on the connecting portion 21, and the valve can be an electrically controlled valve.

The working process and principle of the plasma window unit 2 are as follows: a high voltage is applied to the tip discharge unit 22, and the tip discharge tungsten needle 22 discharges at the tip, and plasma is excited in the quartz glass tube 23. At the same time, the tip discharge tungsten needle 22 delivers inert gas into the quartz glass tube 23 to maintain the stability of the plasma in the quartz glass tube 23. After the plasma is excited, the tip discharge stops. Then, an alternating electric field of 13.56MHz is applied to the inductor 24 to confine the plasma through inductive coupling to maintain the stable state of the plasma; while the inductor 24 maintains the stable state of the plasma, the inert gas is continuously injected into the quartz glass tube 23 through the internal channel of the tip discharge tungsten needle 221, so as to further improve the stable state of the plasma in the quartz glass tube 23. As shown in FIG6 , the electrostatic lens unit 3 mainly includes a first electrostatic lens element 31, a second electrostatic lens element 32, an upper deflection electrode 33, a lower deflection electrode 34, an electrode insulating material 35, a nozzle 36, etc. The first electrostatic lens unit 31 and the second electrostatic lens unit 32 are arranged adjacent to each other to realize the two-stage focusing of the plasma window output ion beam, control the diameter of the output ion beam, and reduce the emission angle of the ion beam again. The upper and lower deflection electrodes mainly change the angle of the ion beam deflection optical axis. The deflection electrodes are two coaxial identical annular electrodes. The two deflection electrodes are set at a distance of 6 mm. The electrode material is selected from copper, and the electrode material is polished to obtain a high-quality surface to avoid electrode discharge caused by micro-protrusions of the electrode material. And fill the insulating material between the deflection electrodes to avoid electrode contact discharge. The role of the nozzle 36 is to once again realize the focusing effect of the ion beam and once again reduce the beam spot diameter of the ion beam. The beam spot diameter is reduced to about 4 mm.

In the present invention, in addition to realizing the extraction of the ion beam from the vacuum environment through the plasma window, a gold dielectric window or a titanium dielectric window or other dielectric windows can also be used as an electron beam extraction window to realize the extraction of the ion beam.

For example, the gold dielectric window includes a window and a gold film disposed in the window, the thickness of the gold film is about 20 μm to 50 μm, the gold dielectric window is disposed at the exit of the ion acceleration unit 1, and the ion beam passes through the gold film and enters the electrostatic lens unit 3. Gold has a low secondary electron emission rate, which means that it is not easy to emit too many electrons due to incident ions or radiation, which helps to maintain the stability of the ion beam; furthermore, gold has good thermal stability and can withstand the high temperature that may be generated during the operation of the equipment, and gold has high chemical stability and can work in a corrosive environment, thereby extending the service life of the dielectric window.

Titanium dielectric windows are commonly used, including a window and a titanium film disposed in the window, and the thickness of the titanium film is generally 15 μm to 50 μm. The titanium film dielectric window and the gold dielectric window are disposed in the same position, and will not be described in detail.

The working process of the plasma window in-situ ion implantation modification system for hard and brittle material processing of the present invention is as follows:

The ion source (ion beam generator) is mainly used to generate an ion beam, and by controlling the process parameters, the beam intensity and energy are changed, and then the ion beam output, focusing and other functions are realized with the help of the acceleration voltage. Then, the parallel ion beam output by the ion acceleration unit 1 enters the plasma window 2, and the plasma window 2 obtains a confined high-density plasma by means of the tip discharge and inductive coupling under the gas, and the ion beam is output to the atmospheric environment through the confined plasma. Then, the output ion beam is focused twice by two groups of electrostatic lens elements of the electrostatic lens unit 3, and then the deflection of the ion beam output beam angle is realized by means of the upper and lower deflection electrodes, and finally, the ion beam is refocused again with the help of the nozzle.

First, the plasma window 2 excites plasma in the quartz glass tube 23 through the tip discharge unit 22, and maintains the stable state of the plasma through the constraints of the inert gas and the inductor 23; then, the valve on the connecting part 21 is opened, and the ion beam ejected by the ion acceleration unit 1 (the ion beam generated in a vacuum environment) enters the quartz glass tube 23 through the connecting part, and the stable plasma in the quartz glass tube 23 is used to isolate the ion beam from the atmosphere; then, it is focused by the electrostatic lens unit 3 and injected into the surface of the workpiece to modify the workpiece.

The present invention also discloses a plasma window in-situ ion implantation modification method for hard and brittle material processing, which is implemented by using the above system. The specific contents of the method are as follows:

S1: Generate an ion beam in a vacuum environment and control the ion beam to move in parallel. The specific implementation process is as follows:

The ion source (ion beam generating device) generates an ion beam and changes the beam intensity and energy by controlling process parameters; then, the ion beam output and focusing are achieved with the help of acceleration voltage, and an alternating magnetic field is generated by a scanning electromagnetic coil to deflect the ion beam back and forth, so that the beam becomes straight and forms a fan-shaped ion beam; then, the collimation electromagnetic coil focuses the divergent ion beam into a uniform ion beam to obtain a parallel moving ion beam.

S2: The parallel moving ion beam enters the plasma window 2, and the plasma window 2 obtains a confined high-density plasma by means of tip discharge and inductive coupling under the gas, and the ion beam is output to the atmospheric environment through the confined plasma. The specific implementation process is as follows:

The tip discharge unit 22 performs tip discharge under the action of a strong electric field to form a high-density plasma in the quartz glass tube 23, and applies an AC electric field of 13.56 MHz to the inductor 24. The magnetic field generated by the discharge of the inductor constrains the high-density plasma to ensure the stability of the plasma. Then, the ion beam isolated from the atmospheric environment by the plasma is output into the atmospheric environment.

S3: After the ion beam output from the plasma window 2 is focused, it acts on the surface of the workpiece to adjust the ion beam implantation area, and finally realizes the ion beam implantation modification in the atmospheric environment. The specific implementation process is as follows:

The ion beam output from the plasma window 2 enters the electrostatic lens unit 3, and first passes through the first electrostatic lens unit 31 and the second electrostatic lens unit 32 to achieve two-stage focusing of the ion beam output from the plasma window, control the diameter of the output ion beam, and reduce the emission angle of the ion beam again.

The upper and lower deflection electrodes change the angle of the ion beam deflection optical axis, and finally the ion beam is focused again through the nozzle 36, and the beam spot diameter of the ion beam is reduced again before being output to act on the surface of the workpiece to achieve ion beam implantation modification in the atmospheric environment.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (11)

1. A plasma window-based in-situ ion implantation modification method for hard and brittle material processing, characterized in that: an ion source generates an ion beam, the ion beam is led out of a vacuum environment through a dielectric window, an electrostatic lens is used to focus the ion beam, the ion beam implantation area is adjusted, and finally the ion beam implantation modification is achieved in an atmospheric environment. 2. The in-situ ion implantation modification method based on plasma window for hard and brittle material processing according to claim 1 is characterized in that the dielectric window is a plasma window, a gold dielectric window or a titanium dielectric window. 3. The plasma window in-situ ion implantation modification method for hard and brittle material processing according to claim 2 is characterized in that it specifically comprises the following steps: S1: Generate an ion beam and control the ion beam to move in parallel; S2: The parallel moving ion beam enters the plasma window. The plasma window obtains a confined high-density plasma by means of tip discharge and inductive coupling under the gas. The ion beam is output to the atmospheric environment through the confined plasma. S3: After the ion beam output from the plasma window is focused, it acts on the surface of the workpiece to adjust the ion beam implantation area, and finally realizes ion beam implantation modification in the atmospheric environment. 4. The in-situ ion implantation modification method based on plasma window for hard and brittle material processing according to claim 3 is characterized in that: in step S1, the ion source generates an ion beam, and changes the beam intensity and energy by controlling process parameters; then, the ion beam output is realized with the help of acceleration voltage, and an alternating magnetic field is generated by a scanning electromagnetic coil to deflect the ion beam back and forth to realize a straight beam and form a fan-shaped belt-shaped ion beam; then, the collimation electromagnetic coil focuses the divergent ion beam into a uniform ion beam to obtain a parallel moving ion beam. 5. According to claim 3, the in-situ ion implantation modification method based on plasma window for hard and brittle material processing is characterized in that: in step S2, the tip discharge unit performs tip discharge under the action of a strong electric field to form plasma, an AC electric field is applied to the inductor coil, and the magnetic field generated by the discharge of the inductor coil constrains the high-density plasma to ensure the stability of the plasma, and then the ion beam is output to the atmospheric environment after being constrained by the plasma. 6. According to claim 3, the in-situ ion implantation modification method based on plasma window for hard and brittle material processing is characterized in that: in step S3, the ion beam output by the plasma window first passes through a two-stage electrostatic lens element to achieve two-stage focusing of the ion beam, controls the diameter of the output ion beam, and reduces the emission angle of the ion beam again; then, the angle of the deflection optical axis of the ion beam is changed by the upper and lower deflection electrodes, and finally the ion beam is focused again through the nozzle, and the beam spot diameter of the ion beam is reduced before being output to act on the surface of the workpiece. 7. A plasma window in-situ ion implantation modification system for hard and brittle material processing, which implements the modification method according to any one of claims 1 to 6, characterized in that it comprises an ion acceleration unit, a plasma window unit and an electrostatic lens unit; The ion acceleration unit is used to generate and control the parallel motion of the ion beam; The plasma window unit is used to output the ion beam to the atmospheric environment through the confined plasma rear body; The electrostatic lens unit is used to achieve focusing of the ion beam. 8. According to claim 7, the plasma window-based in-situ ion implantation modification system for hard and brittle material processing is characterized in that: the ion acceleration unit includes an ion source, an accelerator, a focusing lens, a scanning electromagnetic coil and a collimating electromagnetic coil; the ion source generates ions and draws out the ions through an electric field, the scanning electromagnetic coil realizes a straight beam to form a fan-shaped belt-shaped ion beam, and the collimating electromagnetic coil focuses the ion beam to obtain a parallel moving ion beam. 9. The plasma window-based in-situ ion implantation modification system for hard and brittle material processing according to claim 7 is characterized in that: the plasma window unit includes a tip discharge unit, a quartz glass tube, an inductor coil, and a copper plate, the tip discharge unit is connected to the quartz glass tube, the quartz glass tube is arranged along the central axis, a plurality of copper plates are arranged at intervals on the outer periphery of the quartz glass tube, and an inductor coil wrapped around the outer periphery of the quartz glass tube is arranged between the copper plates. 10. The plasma window-based in-situ ion implantation modification system for hard and brittle material processing according to claim 9 is characterized in that: ceramic insulating material is filled between the copper plate and the inductor coil, and a first cooling pipeline is arranged in the copper plate to cool the copper plate. 11. The plasma window-based in-situ ion implantation modification system for hard and brittle material processing according to claim 7 is characterized in that the electrostatic lens unit mainly includes two adjacent electrostatic lens elements, two coaxially arranged deflection electrodes, and a nozzle for realizing ion beam refocusing.