Ion beam diameter adjusting device for ion beam processing

Abstract

The present application relates to the technical field of ion beam ultra-precision machining, and particularly relates to an ion beam diameter adjusting device for ion beam machining, comprising an adjusting main body, a graphite base, a graphite disc, a cover plate and a heat dissipation structure, wherein the adjusting main body is provided with a first central through hole; the graphite base is arranged at the other end of the adjusting main body, one graphite disc is installed on the graphite base, the graphite disc is provided with a second central through hole for the ion beam to pass through, and the second central through hole is in communication with the first central through hole; the cover plate is covered on the graphite base; and the heat dissipation structure comprises a heat conduction ring and a water-cooled coil pipe, the heat conduction ring is arranged on the adjusting main body, and the water-cooled coil pipe is arranged around the outside of the heat conduction ring. The present application is adapted to the requirements of different spatial frequency error modification by the easily-replaced graphite disc; the efficient heat dissipation system is integrated, the absorbed heat can be timely discharged, and the thermal deformation is effectively inhibited.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ion beam ultra-precision machining, and particularly relates to an ion beam diameter adjusting device for ion beam machining. BACKGROUND

[0002] Since the development of ion beam machining technology in the 1980s, it has become one of the means for ultra-precision optical surface shaping. Its physical basis is ion sputtering effect: in a vacuum environment, high-energy inert gas ions generated by an ion source are accelerated and bombard the surface of an optical element, and through momentum transfer, the atoms or molecules on the surface of the workpiece are physically "sputtered" and removed. The whole process is a non-contact machining process, which avoids the problems of surface / subsurface damage, tool wear, abrasive residue and edge effect caused by traditional mechanical polishing, and is suitable for machining aspherical surfaces and optical elements with extremely high precision requirements, such as extreme ultraviolet lithography projection objectives, large astronomical telescope primary mirrors, and mirrors in high-energy laser devices.

[0003] The ion source is the core component of the IBF system, and its performance directly determines the stability, symmetry, half-width and peak removal rate of the removal function. Among the many types of ion sources, Kaufman-type ion sources are widely used due to their mature technology, uniform beam density and stable operation. Its typical working principle is: in the discharge chamber, plasma is generated through gas discharge between the cathode and the anode, and ions are then extracted and accelerated by the multipole grid to form a directional ion beam.

[0004] However, the traditional IBF process faces a core contradiction: the error spectrum of the surface of an optical element usually contains various spatial frequencies from low frequency, medium frequency to high frequency. For the correction of large-scale low-frequency errors, a larger beam diameter is needed to achieve high-efficiency material removal; while for the control of medium-frequency errors, a smaller beam diameter is needed to obtain higher spatial resolution and prevent the introduction of new high-frequency disturbances. Most existing commercial ion sources have relatively fixed beam diameter size and energy distribution patterns after the mechanical structure and electrical parameters are determined, and lack online rapid adjustment capability. If the shaping requirements of different frequency bands are to be considered in the same machining process, the operator can only adopt a compromise beam diameter parameter or aperture assembly. At the same time, the aperture used to adjust the ion beam diameter is mostly made of metal blades, such as aluminum, copper or stainless steel; when intercepting the ion beam, its sputtering yield is relatively high, which easily produces metal particle contaminants, causing pollution to the vacuum environment and the work surface; at the same time, it lacks an efficient and uniform active heat dissipation structure, making it difficult to guarantee the thermal stability under long-time and high-power machining. SUMMARY

[0005] Therefore, the application aims to provide an ion beam diameter adjusting device for ion beam processing, which can quickly switch different ion beam constraint sizes without changing the main body structure, adapt to the shaping requirements of different spatial frequency errors, and integrate an efficient heat dissipation system to timely discharge the absorbed heat, effectively inhibit thermal deformation, and ensure the shape stability of the removal function during long-time processing.

[0006] To achieve the above-mentioned purposes, the technical scheme of the application is as follows:

[0007] An ion beam diameter adjusting device for ion beam processing is used to adjust the diameter of the ion beam emitted from the outlet of an ion source, comprising:

[0008] An adjusting main body, one end of the adjusting main body is connected with the flange of the outlet of the ion source, and the adjusting main body is provided with a first central through hole for the ion beam to pass through;

[0009] A hollow graphite base, the graphite base is arranged at the other end of the adjusting main body,

[0010] Two graphite discs, one graphite disc is arranged in the graphite base, the graphite disc is provided with a second central through hole for the ion beam to pass through, the second central through hole is communicated with the first central through hole and the hollow graphite base, the diameter of the second central through hole is smaller than the hole diameter of the hollow graphite base and the diameter of the first central through hole, and the diameter of the ion beam is limited by the second central through hole;

[0011] A hollow cover plate, the cover plate covers the graphite base and presses the graphite disc in the graphite base, the second central through hole is communicated with the hollow cover plate, and the hole diameter of the cover plate is larger than the diameter of the second central through hole;

[0012] A heat dissipation structure, the heat dissipation structure comprises a heat conduction ring and a water-cooled coil pipe, the heat conduction ring is arranged on the adjusting main body, the outer side of the heat conduction ring is surrounded by the water-cooled coil pipe, and the heat generated by the adjusting main body is transmitted by the heat conduction ring and the water-cooled coil pipe in sequence.

[0013] Further, the top surface of the graphite base is inwardly recessed to form a containing groove, and the graphite disc is arranged in the containing groove; eight first stepped holes are arranged on the bottom wall of the containing groove and close to the side wall; eight first positioning holes are arranged on the top surface of the graphite base and close to the edge; the first stepped holes and the first positioning holes are annularly distributed around the axis of the third central through hole; the bottom surface of the graphite base is outwardly protruded to form a second annular protrusion, the second annular protrusion is embedded in the second central through hole; the middle part of the groove bottom of the containing groove is inwardly recessed to form a third central through hole, the third central through hole is communicated with the through hole of the second annular protrusion, the third central through hole is communicated with the second central through hole and the first central through hole, the third central through hole is larger than the hole diameter of the second central through hole, and the diameters of the second central through holes are adjusted to adjust the diameter of the ion beam.

[0014] Further, the number of graphite discs is at least two, the aperture of the second central through hole of the at least two graphite discs is different, the beam diameter of the ion beam is adjusted by replacing the second central through hole with different aperture, eight second stepped holes are arranged on the top surface of the graphite disc near the edge, the bottom surface of the graphite disc is outwardly protruded to form a first annular protrusion near the second central through hole, the first annular protrusion is embedded in the third central through hole, the second stepped hole is connected with the corresponding first stepped hole through the first screw, and the graphite disc is fixed in the accommodating groove of the graphite base.

[0015] Further, the top surface of the cover plate is inwardly recessed to form a fourth central through hole, the top surface of the cover plate is outwardly protruded to form a third annular protrusion near the fourth central through hole, the first annular protrusion is embedded in the fourth central through hole, the fourth central through hole is communicated with the second central through hole, the aperture of the fourth central through hole is larger than that of the second central through hole, the beam diameter of the ion beam is limited through the second central through hole, the outer circumferential surface of the third annular protrusion is outwardly protruded to form four positioning blocks, the positioning blocks extend to the outer wall of the cover plate, the top surface of the positioning block is arranged with a second positioning hole, the second positioning hole and the corresponding first positioning hole are connected through the second screw, the cover plate is fixed on the graphite base, and the graphite disc is pressed in the accommodating groove.

[0016] Further, the bottom end of the adjusting body is outwardly protruded to form a connecting ring, the outer diameter of the connecting ring is larger than the outer diameter of the adjusting body, the connecting ring is connected with the flange through the bolt, the top end of the adjusting body is provided with a cone, the top end of the cone is provided with a positioning ring, the first central through hole penetrates the cone, the adjusting body, the connecting ring and the positioning ring, and is used for the ion beam to pass through; the top surface of the cone is arranged with eight third positioning holes inside the positioning ring, the third positioning hole, the corresponding second positioning hole and the corresponding first positioning hole are connected through the second screw, and the graphite base is fixed on the cone and located in the positioning ring.

[0017] Further, the side wall of the cone is arranged with a heat dissipation hole, the heat dissipation hole is arranged in a ring shape along the axis of the cone, and the heat dissipation area of the cone is increased.

[0018] Further, the heat dissipation structure further comprises two female splices, two male splices and two cooling water hoses, one end of the two female splices is communicated with two ends of the water-cooled coil, the heat conduction ring is arranged on the positioning ring and is in interference fit with the positioning ring, the other end of the two female splices is spliced with one end of the corresponding male splice, and the other end of the two male splices is communicated with the corresponding cooling water hose, so that cold water is added into the water-cooled coil to cool the heat conduction ring and the positioning ring.

[0019] Further, the support frame and the support plate are further included, two female connectors are installed on the support frame, two ends of the support frame are connected with the adjusting body through the support plate respectively, and the cooling water hose is away from the adjusting body and the cone.

[0020] Further, the support frame includes a horizontal arc-shaped plate, a vertical arc-shaped plate and a first connecting plate, the vertical arc-shaped plate is fixed on one end of the horizontal arc-shaped plate close to the adjusting body, two ends of the horizontal arc-shaped plate are connected with two ends of the vertical arc-shaped plate through the first connecting plate respectively, the first connecting plate is connected with one end of the support plate, and two female connectors are installed on the horizontal arc-shaped plate and close to the first connecting plate respectively; the ends of the horizontal arc-shaped plate and the vertical arc-shaped plate away from each other are recessed inward to form grooves, and the vertical arc-shaped plate is arranged on the outer side of the connecting ring, so that the cooling water hose is away from the adjusting body.

[0021] Further, the support plate includes an L-shaped connecting plate, an inclined plate, a square connecting plate and a second connecting plate, two ends of the L-shaped connecting plate are connected with the square connecting plate and the inclined plate respectively, the square connecting plate is installed on the outer wall of the adjusting body through a third screw, the inclined plate is connected with the second connecting plate, and the second connecting plate is installed on the outer side of the first connecting plate through a fourth screw, so as to support the horizontal arc-shaped plate, the vertical arc-shaped plate and the first connecting plate.

[0022] Compared with the prior art, the application can achieve the following beneficial effects:

[0023] (1) The graphite disc has a second central through hole with different hole diameters to realize discrete but precise beam diameter control. The complex motion mechanism is avoided, the precision depends on the machining precision of the graphite disc, and the precision can usually reach within ±0.05 mm, which is much higher than the repeat positioning precision of the adjustable diaphragm, and the switching operation is quick and simple;

[0024] (2) The adjusting body is welded with the heat conduction ring, and the water cooling coil is integrated, so as to form a high-efficiency three-dimensional heat dissipation system. The heat absorbed by the graphite passes through the adjusting body, the heat conduction ring, the water cooling coil and the cooling water in sequence, the heat conduction efficiency of the above heat path is high, the thermal resistance is small, and the stability and repeatability of long-time and high-power processing are guaranteed;

[0025] (3) The graphite disc and the graphite base are both made of graphite material, the graphite material has high resistance to ions, the sputtering product has little pollution to most optical workpieces, the pollution of carbon as the sputtering product is relatively easy to handle, the cleanliness in the vacuum chamber is maintained, and the expensive optical workpiece is protected; the graphite disc can be made into a thin structure, the blocking area of the useless beam is reduced, the effective beam density reaching the workpiece is higher, and the peak removal rate and overall processing efficiency are improved;

[0026] (4) The modular design created by this invention makes the replacement and maintenance of the graphite disk and graphite disk base, adjustment body, heat dissipation structure, support frame and support plate very intuitive and simple, reducing maintenance costs and downtime. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 An exploded view of the ion beam diameter adjustment device for ion beam processing described in the embodiments of the present invention;

[0029] Figure 2 A schematic diagram of the ion beam diameter adjustment device for ion beam processing as described in the embodiments of the present invention;

[0030] Figure 3 for Figure 1 A schematic diagram of the structure with the cover plate removed.

[0031] Figure 4 for Figure 1 A schematic diagram of the connection structure of the main body, connecting ring, frustum, and positioning ring;

[0032] Figure 5 for Figure 1 Schematic diagram of the central heat-conducting ring;

[0033] Figure 6 for Figure 1 Schematic diagram of the structure of the water-cooled coil;

[0034] Figure 7 for Figure 1 Schematic diagram of the graphite base;

[0035] Figure 8 for Figure 1 Schematic diagram of the graphite disk structure;

[0036] Figure 9 for Figure 1 Schematic diagram of the middle cover plate;

[0037] Figure 10 for Figure 1 Schematic diagram of the middle support frame;

[0038] Figure 11 for Figure 1 Schematic diagram of the middle support plate;

[0039] Figure 12The surface shape diagram before processing of the ion beam machining ion beam diameter adjusting device according to the embodiment of the present application;

[0040] Figure 13 The surface shape diagram after processing of the ion beam machining ion beam diameter adjusting device according to the embodiment of the present application.

[0041] Explanation of reference signs:

[0042] 10, adjusting main body; 11, first center through hole; 12, connecting ring; 13, cone; 14, positioning ring; 15, third positioning hole; 16, heat dissipation hole;

[0043] 20, graphite base; 21, accommodating groove; 22, third center through hole; 23, first stepped hole; 24, first positioning hole; 25, second annular protrusion;

[0044] 30, graphite disc; 31, second center through hole; 32, second stepped hole; 33, first annular protrusion;

[0045] 40, cover plate; 41, third annular protrusion; 42, fourth center through hole; 43, positioning block; 44, second positioning hole;

[0046] 50, heat conducting ring; 51, water cooling coil; 52, cooling water hose; 53, female plug; 54, male plug;

[0047] 60, support frame; 61, horizontal arc plate; 62, vertical arc plate; 63, first connecting plate; 64, groove;

[0048] 70, support plate; 71, L-shaped connecting plate; 72, inclined plate; 73, square connecting plate; 74, second connecting plate. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not constitute a limitation on the present application.

[0050] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0051] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0052] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0053] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0054] As shown in Figures 1 to 3 An ion beam machining ion beam diameter adjusting device for adjusting the beam diameter of the ion beam emitted from the outlet of the ion source, comprising:

[0055] An adjusting body 10, one end of the adjusting body 10 is connected with the flange of the outlet of the ion source, the adjusting body 10 has a first central through hole 11 for the ion beam to pass through, the adjusting body 10 serves as the mounting platform of the entire device, and is made of lightweight high-strength aluminum alloy 2A12. This material belongs to high-strength hard aluminum, has the characteristics of small density, high specific stiffness, excellent mechanical processing performance, etc., and is very suitable for being used as a structural part in a vacuum environment;

[0056] A hollow graphite base 20, the graphite base 20 is arranged at the other end of the adjusting body 10,

[0057] Two graphite disks 30, one graphite disk 30 is installed in the graphite base 20, the graphite disk 30 is provided with a second central through hole 31 for the ion beam to pass through, the second central through hole 31 is communicated with the first central through hole 11 and the hollow graphite base 20, the diameter of the second central through hole 31 is smaller than the hole diameter of the hollow graphite base 20 and the diameter of the first central through hole 11, the hole diameters of the second central through holes 31 of the at least two graphite disks 30 are all different, and the beam diameter of the ion beam is adjusted by replacing the second central through holes 31 with different hole diameters;

[0058] A hollow cover plate 40 covers the graphite base 20 and presses the graphite disk 30 in the graphite base 20, the second central through hole 31 is communicated with the hollow cover plate 40, and the hole diameter of the cover plate 40 is greater than the diameter of the second central through hole 31;

[0059] A heat dissipation structure includes a heat conduction ring 50 and a water cooling coil 51, the heat conduction ring 50 is vacuum brazed to the adjustment body 10, so that the heat on the adjustment body 10 is quickly and lowly conducted out, and the huge heat capacity of the heat conduction ring 50 also helps to buffer the instantaneous heat shock; the outer side of the heat conduction ring 50 is surrounded by the water cooling coil 51, the heat conduction ring 50 conducts heat to the adjustment body 10, and the water cooling coil 51 takes away the heat emitted by the heat conduction ring 50; the heat conduction ring 50 is mechanically fixed on the adjustment body 10 by two M5x20 screws and a gasket, aiming to improve the structural reliability and prevent the welding from failing due to thermal stress or vibration in extreme cases; the contact surface between the water cooling coil 51 and the heat conduction ring 50 is welded by argon arc welding, so as to ensure that the thermal contact resistance between the two is extremely small.

[0060] Specifically, the original ion beam introduced from the ion source passes through the second central through hole 31 in the graphite base 20 and the graphite disk 30, the second central through hole 31 transversely limits the ion beam and determines the basic diameter of the ion velocity. In the above process, a part of ions with higher energy or larger angle deviation will hit the hole wall of the second central through hole 31 in the graphite disk 30 and the graphite base 20, and convert the kinetic energy into heat energy. The above heat is conducted through the graphite material of the graphite base 20 and the graphite disk 30, and is transmitted to the adjustment body 10 through the contact interface. The heat conduction ring 50 welded on the adjustment body 10 acts as a high-efficiency heat conductor, rapidly transmitting the collected heat to the water cooling coil 51 welded thereon. The cooling water flows in the water cooling coil 51, continuously taking away the heat, so as to maintain the entire cutting-off device in a relatively stable low-temperature working state. The cover plate 40 is used to press the graphite disk 30, so as to ensure accurate positioning and good contact.

[0061] By replacing different graphite discs 30, the second central through hole 31 of different aperture is used to quickly switch the size of the ion beam, adapt to the correction requirement of different spatial frequency error, and at the same time, the efficient heat dissipation structure is integrated, so that the heat absorbed by the device can be discharged in time, the thermal deformation is effectively inhibited, and the shape stability of the removal function in the long-time processing process is ensured.

[0062] The graphite disc 30 is a replaceable component, which is fixed in the graphite base 20 by screws, and the aperture of the second central through hole 31 is accurately designed according to the target ion beam diameter. The user can select and install the graphite disc 30 with different central aperture according to the processing process requirement, so as to realize flexible and accurate control of the outgoing ion beam flow half-width.

[0063] The graphite disc 30 of the present application is made of graphite material, which has the excellent characteristics of high temperature resistance, small thermal expansion coefficient, good thermal conductivity, high ion beam absorption rate and low sputtering yield, etc. The second central through hole 31 is arranged at the center position of the graphite disc 30, which can realize ion beam shaping, reduce unnecessary blocking of useful ion beam as much as possible, and improve processing efficiency and consistency.

[0064] The graphite disc 30 can also be made of refractory metals such as high-purity tungsten, molybdenum or tantalum, or high-performance ceramic materials such as aluminum oxide and aluminum nitride, so that the graphite disc 30 has excellent high temperature resistance and sputtering resistance.

[0065] The heat dissipation structure is active heat dissipation, and the heat conduction ring 50 acts as a heat conduction bridge to quickly transfer the heat absorbed by the adjustment main body 10 to the water-cooled coil 51. The cooling water continuously flowing in the water-cooled coil 51 carries away the heat, forming a high-efficiency forced convection cooling loop, which ensures that the working temperature of the adjustment main body 10, the graphite base 20 and the graphite disc 30 is stable within the allowable range.

[0066] The heat conduction ring 50 and the water-cooled coil 51 can be made of molybdenum-copper alloy or high-thermal-conductivity carbon material (such as pyrolytic graphite), and the surface is metallized for welding. In the case of limited space, the water-cooled coil 51 can be arranged inside the heat conduction ring 50, and the cooling flow channel is directly machined.

[0067] The heat conduction ring 50 and the adjustment main body 10 can be designed as a whole, which is machined after casting (such as vacuum pressure casting), and the cooling flow channel is pre-embedded inside, which can completely eliminate the welding process.

[0068] As Figures 1 to 3 , Figures 5 to 7As shown, the top surface of the graphite base 20 is inwardly recessed to form a receiving groove 21, and the graphite disc 30 is arranged in the receiving groove 21; eight first stepped holes 23 are arranged on the bottom wall of the receiving groove 21 and close to the side wall; eight first positioning holes 24 are arranged on the top surface of the graphite base 20 and close to the edge, the first positioning holes 24 are m5x25 countersunk screw holes, the first stepped holes 23 and the first positioning holes 24 are annularly distributed around the axis of the third central through hole 22, the bottom surface of the graphite base 20 is outwardly protruded to form a second annular protrusion 25, the second annular protrusion 25 is embedded in the second central through hole 31, the middle part of the groove bottom of the receiving groove 21 is inwardly recessed to form the third central through hole 22, the third central through hole 22 is in communication with the through hole of the second annular protrusion 25, the third central through hole 22 is in communication with the second central through hole 31 and the first central through hole 11, the third central through hole 22 is larger than the hole diameter of the second central through hole 31, and the beam diameter of the ion beam is adjusted through the second central through hole 31 with different hole diameters.

[0069] The graphite base 20 can conduct part of the heat received by the graphite disc 30 to the adjustment body 10, and the third central through hole 22 is generally slightly larger than the second central through hole 31, which plays a role of auxiliary beam passing and secondary interception.

[0070] As shown in Figures 1 to 3 , Figure 8 , eight second stepped holes 32 are arranged on the top surface of the graphite disc 30 close to the edge, the bottom surface of the graphite disc 30 is outwardly protruded to form a first annular protrusion 33 close to the second central through hole 31, and four second stepped holes 32 and corresponding first stepped holes 23 are selectively arranged at intervals and connected by screws, so as to fix the graphite disc 30 in the receiving groove 21 of the graphite base 20.

[0071] The graphite disc 30 directly faces the ion beam and is a part for performing the main beam cutting and shaping function. The second central through hole 31 limits the boundary and half-width of the outgoing ion beam. By replacing the graphite disc 30 with different hole diameters, the ion beam diameter can be quickly switched, greatly improving the process flexibility.

[0072] The adjustment body 10 can be made of stainless steel (such as 304SS) or invar, so as to be suitable for occasions with higher strength or lower thermal expansion.

[0073] As shown in Figures 1 to 3 , Figure 9As shown, the top surface of the cover plate 40 is inwardly recessed in the middle to form a fourth central through hole 42, and the top surface of the cover plate 40 and close to the fourth central through hole 42 is outwardly protruded to form a third annular protrusion 41, the first annular protrusion 33 is embedded in the fourth central through hole 42, the fourth central through hole 42 is communicated with the second central through hole 31, the aperture of the fourth central through hole 42 is larger than the aperture of the second central through hole 31, the beam diameter of the ion beam is limited through the second central through hole 31, and the outer circumferential surface of the third annular protrusion 41 is outwardly protruded to form four positioning blocks 43, the positioning blocks 43 extend to the outer wall of the cover plate 40, and the middle of the top surface of the positioning block 43 is provided with a second positioning hole 44, and the four second positioning holes 44 are selectively arranged and connected with the corresponding first positioning holes 24 through the second screws, so as to fix the cover plate 40 on the graphite base 20 and press the graphite disc 30 in the accommodating groove 21.

[0074] The cover plate can ensure that the graphite disc 30 is in close contact with the installation plane of the graphite base 20, so as to establish a good heat conduction path and prevent the graphite disc 30 from vibrating or shifting under the impact of the ion beam.

[0075] As shown in the figure, Figures 1 to 4 The bottom end of the adjusting body 10 is outwardly protruded to form a connecting ring 12, the outer diameter of the connecting ring 12 is larger than the outer diameter of the adjusting body 10, eight M6 through holes are uniformly arranged on the connecting ring 12 and connected with the flange through bolts to realize the fixation of the whole device, the top end of the adjusting body 10 is provided with a frustum 13, the top end of the frustum 13 is provided with a positioning ring 14, the first central through hole 11 penetrates through the frustum 13, the adjusting body 10, the connecting ring 12 and the positioning ring 14 and is used for the ion beam to pass through, eight third positioning holes 15 are arranged on the top surface of the frustum 13 and inside the positioning ring 14, the third positioning holes 15 are m5x25 threaded holes, the third positioning holes 15, the corresponding second positioning holes 44 and the corresponding first positioning holes 24 are connected through the second screws, so as to fix the graphite base 20 on the frustum 13 and inside the positioning ring 14, and the setting of the positioning ring 14 ensures the accuracy of the axial position of the graphite base 20.

[0076] The adjusting body 10 precisely positions the graphite base 20 through the positioning ring 14 and precisely docks with the flange of the ion source outlet through the connecting ring 12, so as to effectively ensure the precise installation and replacement of the graphite disc 30.

[0077] At least eight heat dissipation holes 16 are arranged on the side wall of the frustum 13 and arranged in a ring shape along the axis of the frustum 13, so as to increase the heat dissipation area of the frustum 13.

[0078] At least eight heat dissipation holes 16 can form a multi-row heat dissipation hole array to increase the heat dissipation area, utilize the residual gas in the vacuum chamber for limited convection heat dissipation, help air convection, and assist heat dissipation; at the same time, provide an escape channel for ions whose energy and direction have deviated from the main beam after multiple scattering, prevent accumulation of the ions in the adjustment body 10 to cause discharge or unnecessary heating, that is, allow a small amount of scattered ions that are not completely absorbed by the graphite assembly to overflow to avoid accumulation of electric charges in the cavity.

[0079] The heat dissipation structure further comprises two female connectors 53, two male connectors 54, and two cooling water hoses 52. One end of the two female connectors 53 is in communication with two ends of the water-cooled coil 51. The heat conduction ring 50 is sleeved on the positioning ring 14 and is in interference fit with the positioning ring 14 to ensure the pre-tightening force before welding and the contact area after welding. The other end of the two female connectors 53 is inserted with one end of the corresponding male connector 54. The other end of the two male connectors 54 is in communication with the corresponding cooling water hose 52, which is used to add cold water to the water-cooled coil 51 to cool the heat conduction ring 50 and cool the positioning ring 14.

[0080] As shown in Figures 1 to 3 , Figure 10 , the heat dissipation structure further comprises a support frame 60 and a support plate 70. The two female connectors 53 are both mounted on the support frame 60. The two ends of the support frame 60 are connected with the adjustment body 10 through the support plate 70 respectively, which is used to keep the cooling water hose 52 away from the adjustment body 10 and the cone 13.

[0081] The support frame 60 and the support plate 70 are used to provide a stable mounting point for the external female connector 53 and the male connector 54 to prevent stress interference on the core heat dissipation components caused by the gravity or vibration of the cooling water hose 52.

[0082] The female connector 53 and the male connector 54 can be selected from the Swagelok brand connector, which has the advantages of reliable connection, good sealing, and allowing quick plugging and unplugging. The female connector 53 is connected with the water-cooled coil 51 and is mounted on the support plate 70. The male connector 54 is connected with the cooling water hose 52. Through the insertion of the female connector 53 and the male connector 54, the water-cooled pipe is connected with the adjustment body 10 conveniently. At the same time, the water-cooled pipe is separated from the adjustment body 10 through the support plate 70, which greatly facilitates the installation and maintenance of the device.

[0083] As shown in Figures 1 to 3 , Figure 11As shown, the support frame 60 comprises a horizontal arc-shaped plate 61, a vertical arc-shaped plate 62 and a first connecting plate 63, the vertical arc-shaped plate 62 is fixed on the horizontal arc-shaped plate 61 near one end of the adjustment body 10, the two ends of the horizontal arc-shaped plate 61 and the two ends of the vertical arc-shaped plate 62 are connected by the first connecting plate 63 respectively, the first connecting plate 63 is connected with one end of the support plate 70, two female splices 53 are installed on the horizontal arc-shaped plate 61 and are close to the first connecting plate 63 respectively; the ends of the horizontal arc-shaped plate 61 and the vertical arc-shaped plate 62 away from each other are recessed inward to form a groove 64, the vertical arc-shaped plate 62 is arranged on the outside of the connecting ring 12, and is used for the cooling water hose 52 away from the adjustment body 10.

[0084] The support plate 70 comprises an L-shaped connecting plate 71, an inclined plate 72, a square connecting plate 73 and a second connecting plate 74, the two ends of the L-shaped connecting plate 71 are connected with the square connecting plate 73 and the inclined plate 72 respectively, the square connecting plate 73 is installed on the outer wall of the adjustment body 10 through a third screw, the inclined plate 72 is connected with the second connecting plate 74, and the second connecting plate 74 is installed on the outer side of the first connecting plate 63 through a fourth screw, and is used for supporting the horizontal arc-shaped plate 61, the vertical arc-shaped plate 62 and the first connecting plate 63.

[0085] The specific assembly process is as follows:

[0086] Step one: the heat conduction ring 50 is sleeved on the outer wall of the positioning ring 14 and is welded;

[0087] Step two: the female splice 53 is inserted through the mounting hole on the horizontal arc-shaped plate 61, and is fixed on the horizontal arc-shaped plate 61 by using a nut matched with the female splice 53;

[0088] Step three: the water-cooled coil pipe 51 is welded on the outer side of the heat conduction ring 50, so that the water-cooled coil pipe 51 is tightly attached to the outer surface of the heat conduction ring 50; the two pipe end openings of the water-cooled coil pipe 51 are connected with the female splice 53 in a clamping sleeve mode and are tightened;

[0089] The contact part of the water-cooled coil pipe 51 and the heat conduction ring 50 can be welded firmly by using argon arc welding;

[0090] Step four: the two square connecting plates 73 are connected with the threaded holes on the outer wall of the adjustment body 10 symmetrically by two M5x20 screws and gaskets respectively; the second connecting plate 74 is installed on the corresponding first connecting plate 63 by four M6x12 screws and gaskets;

[0091] Step five: the graphite base 20 is placed on the conical table 13 and is located in the positioning ring 14, and four M5x25 countersunk head screws are used to connect the third positioning hole 15 and the first stepped hole 23;

[0092] Step six: Select a graphite disc 30 with the appropriate aperture, place it on the mounting plane of the graphite base 20, align the second stepped hole 32 and the first stepped hole 23, and use four M5x16 countersunk screws to connect the corresponding second stepped hole 32 and the first stepped hole 23, respectively, to press and fix the graphite disc 30.

[0093] Step seven: Cover the graphite disc 30 with the cover plate 40, use four M5x25 screws to pass through the second positioning hole 44 and the corresponding first positioning hole 24 and the corresponding third positioning hole 15, and tighten evenly to press the graphite disc 30 with the cover plate 40, completing the final packaging.

[0094] At this point, the entire ion source cutoff device is assembled. Before loading into the vacuum chamber, the water cooling circuit needs to be pressure tested to ensure there is no leakage.

[0095] The various components of the present application are integrated into a whole through mechanical connection, including screw connection and welding, and work together to achieve precise, stable and controllable cutoff and shaping of the ion beam.

[0096] The present application adopts a reasonable split structure and assembly process, making the device structure compact, easy to install, debug, maintain and replace parts, and improving the reliability and ease of use of the entire ion beam processing system.

[0097] The present application has completed the manufacturing, assembly and experimental verification of the prototype.

[0098] Experimental platform: The experiment was conducted on a self-developed Φ4000mm ion beam machining machine, and the ion source was a Kaufman ion source.

[0099] Test: The above process assembled the prototype of the device of the present application and installed graphite discs 30 with second center through holes 31 with diameters of D80mm, D40mm and D20mm for testing.

[0100] Results:

[0101] 1. Beam diameter shape: The Faraday cup was used to measure the beam density distribution. The results show that after replacing different graphite discs 30, the obtained ion beam diameters are 40.5mm, 23.4mm and 15.5mm, which are in good agreement with the design values, and the beam distribution is symmetrical without significant distortion.

[0102] 2. Heat dissipation performance: Under the maximum beam power, continuous operation for 10 hours did not cause ACC short circuit or excessive RF feedback power due to high temperature, indicating that the heat dissipation system works efficiently.

[0103] 3. Removal function stability: During the 8 hours processing, the SiC sample was etched by sputtering and the Faraday cup was scanned every 60 minutes. The measurement results show that the volume removal rate fluctuation of the removal function is less than 2.5%, and the half-width change is less than 0.1mm, which proves the excellent thermal stability and process repeatability of the device.

[0104] 4. Functional processing verification: successfully applied to the surface error correction of a 1500mm aperture SiC aspherical mirror, by switching the D80mm and Φ40mm graphite discs 30, respectively for rough and fine polishing, the final surface accuracy (RMS) converges from the initial 52.899nm to 7.936nm, as shown in Figures 12 to 13

[0105] Experimental conclusion: the device of the application completely achieves the expected design, and is superior to the traditional adjustable diaphragm scheme in terms of beam shaping flexibility, thermal stability and processing performance.

[0106] The above specific embodiments do not constitute a limitation on the protection scope of the application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the application shall be included in the protection scope of the application.​

Claims

1. An ion beam diameter adjustment device for ion beam processing, used to adjust the diameter of the ion beam emitted from the ion source outlet, characterized in that, include: An adjustment body, one end of which is connected to the flange of the ion source outlet, has a first central through hole for the ion beam to pass through; A hollow graphite base is disposed at the other end of the adjustment body; A graphite disk is installed inside a graphite base. The graphite disk has a second central through hole for the ion beam to pass through. The second central through hole communicates with the first central through hole and the hollow graphite base. The diameter of the second central through hole is smaller than the diameter of the hole in the hollow graphite base and the diameter of the first central through hole. The beam diameter of the ion beam is limited by the second central through hole. A hollow cover plate is placed on the graphite base and presses the graphite disk into the graphite base. The second central through hole communicates with the hollow cover plate, and the diameter of the hole in the cover plate is larger than the diameter of the second central through hole. The heat dissipation structure includes a heat-conducting ring and a water-cooling coil. The heat-conducting ring is disposed on the adjustment body, and the water-cooling coil is surrounded on the outside of the heat-conducting ring. The heat generated by the adjustment body is transferred sequentially through the heat-conducting ring and the water-cooling coil.

2. The ion beam diameter adjustment device for ion beam processing according to claim 1, characterized in that: The top surface of the graphite base is recessed inward to form a receiving groove, and the graphite disk is disposed in the receiving groove. A first stepped hole is formed on the bottom wall of the receiving groove near the side wall. A first positioning hole is formed on the top surface of the graphite base near the edge. The first stepped hole and the first positioning hole are both distributed in a ring around the axis of the receiving groove. The bottom surface of the graphite base protrudes outward to form a second annular protrusion. The second annular protrusion is embedded in the second central through hole. The bottom of the receiving groove is recessed inward to form a third central through hole. The third central through hole communicates with the through hole in the middle of the second annular protrusion, the second central through hole, and the first central through hole. The diameter of the third central through hole is larger than that of the second central through hole. The beam diameter of the ion beam is adjusted by using the second central through holes of different diameters.

3. The ion beam diameter adjustment device for ion beam processing according to claim 2, characterized in that: The number of graphite disks is at least two, and the diameter of the second central through hole of the at least two graphite disks is different. The beam diameter of the ion beam is adjusted by changing the second central through hole with different diameters. A second stepped hole is opened on the top surface of the graphite disk near the edge. The bottom surface of the graphite disk protrudes outward near the second central through hole to form a first annular protrusion. The second stepped hole and the corresponding first stepped hole are connected by a first screw for fixing the graphite disk in the receiving groove of the graphite base.

4. The ion beam diameter adjustment device for ion beam processing according to claim 3, characterized in that: The top surface of the cover plate is recessed inward to form a fourth central through hole. The top surface of the cover plate, near the fourth central through hole, protrudes outward to form a third annular protrusion. The first annular protrusion is embedded in the fourth central through hole, which is connected to the second central through hole. The outer circumference of the third annular protrusion protrudes outward to form a positioning block. The positioning block extends to the outer wall of the cover plate. The top surface of the positioning block has a second positioning hole. The second positioning hole and the corresponding first positioning hole are connected by a second screw for fixing the cover plate to the graphite base and pressing the graphite disk into the receiving groove.

5. The ion beam diameter adjustment device for ion beam processing according to claim 4, characterized in that: The bottom end of the adjustment body protrudes outward to form a connecting ring. The outer diameter of the connecting ring is larger than the outer diameter of the adjustment body. The connecting ring is connected to the flange by bolts. The top end of the adjustment body has a truncated cone. The top end of the truncated cone has a positioning ring. The first central through hole passes through the truncated cone, the adjustment body, the connecting ring, and the positioning ring, and is used for the passage of the ion beam. A third positioning hole is opened on the top surface of the truncated cone and inside the positioning ring. The third positioning hole, the corresponding second positioning hole, and the corresponding first positioning hole are connected by the second screw, which is used to fix the graphite base on the truncated cone and inside the positioning ring.

6. The ion beam diameter adjustment device for ion beam processing according to claim 5, characterized in that: The side wall of the cone has heat dissipation holes arranged in a ring along the axis of the cone to increase the heat dissipation area of ​​the cone.

7. The ion beam diameter adjustment device for ion beam processing according to claim 5, characterized in that: The heat dissipation structure also includes two female connectors, two male connectors, and two cooling water hoses. One end of each of the two female connectors is connected to both ends of the water-cooling coil. The heat-conducting ring is fitted onto the positioning ring with an interference fit. The other end of each of the two female connectors is connected to one end of the corresponding male connector. The other end of each of the two male connectors is connected to the corresponding cooling water hose, which is used to add cold water into the water-cooling coil to cool the heat-conducting ring.

8. The ion beam diameter adjustment device for ion beam processing according to claim 7, characterized in that: It also includes a support frame and a support plate. Both of the aforementioned plug-in female heads are mounted on the support frame. The two ends of the support frame are respectively connected to the adjustment body through the support plate, so that the cooling water hose is away from the adjustment body and the cone.

9. The ion beam diameter adjustment device for ion beam processing according to claim 8, characterized in that: The support frame includes a horizontal arc plate, a vertical arc plate, and a first connecting plate. The vertical arc plate is fixed to one end of the horizontal arc plate near the adjusting body. The two ends of the horizontal arc plate and the two ends of the vertical arc plate are respectively connected by the first connecting plate. The first connecting plate is connected to one end of the support plate. Two plug-in females are installed on the horizontal arc plate and are respectively positioned close to the first connecting plate. The ends of the horizontal and vertical arc plates that are far apart are recessed inward to form grooves. The vertical arc plate is located outside the connecting ring so that the cooling water hose is away from the adjusting body.

10. The ion beam diameter adjustment device for ion beam processing according to claim 9, characterized in that: The support plate includes an L-shaped connecting plate, an inclined plate, a square connecting plate, and a second connecting plate. The two ends of the L-shaped connecting plate are connected to the square connecting plate and the inclined plate, respectively. The square connecting plate is installed on the outer wall of the adjustment body by a third screw. The inclined plate is connected to the second connecting plate. The second connecting plate is installed on the outer side of the first connecting plate by a fourth screw, and is used to support the horizontal arc plate, the vertical arc plate, and the first connecting plate.

Images