An ion beam online variable beam diameter processing device and beam diameter variable method

Abstract

The present invention discloses an ion beam online beam diameter changing processing device and a beam diameter changing method thereof. The device of the present invention comprises a base and a top cover. Both the base and the top cover are provided with a central through hole for the ion beam to pass through. The top cover is driven by a motor and rotatably arranged on one side of the central through hole of the base. A side of the base close to the top cover is provided with a plurality of circular holes evenly arranged along the edge of the central through hole. A side of the top cover close to the base is provided with a plurality of guide grooves. A plurality of aperture plates are provided between the base and the top cover to enclose the central through hole to form an aperture hole. A guide column is provided at each end of the aperture plate, and one guide column is inserted and arranged in the circular hole, and the other guide column is slidably arranged in the guide groove. The present invention aims to overcome the problem of repeated switching of vacuum chambers and ion sources during existing ion beam processing to reduce processing efficiency, realize accurate and stable control of the beam diameter changing process, and improve processing accuracy and efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of ion beam ultra-precision processing, and in particular relates to an ion beam online variable beam diameter processing device and a beam diameter variable method thereof. Background Art

[0002] The principle of ion beam processing is to use the physical sputtering effect that occurs when the ion beam emitted by the ion source bombards the surface of the optical element in a vacuum environment, thereby removing the surface material. It has the characteristics of removal function stability, no edge effect and non-contact processing. The larger the beam diameter, the higher the removal function efficiency of the ion beam, but the poorer the processing accuracy. The smaller the beam diameter, the higher the removal function of the ion beam, but the lower the efficiency. In traditional ion beam processing, the beam diameter is intercepted by the ion aperture, and only one ion beam removal function with a larger beam diameter is used at a time to modify the surface shape of the optical element. When the surface shape is improved to a certain accuracy, the beam diameter cannot converge, and then an ion aperture with a smaller aperture is used to obtain a smaller beam diameter, thereby improving the processing accuracy. In this process, it is necessary to turn off the ion source, open the vacuum chamber, replace the aperture, and re-evacuate, which greatly reduces the processing efficiency. Even switching the ion source on and off multiple times will cause the removal function parameters to change from the original measurement. Summary of the invention

[0003] Technical problem to be solved by the present invention: In view of the above-mentioned problems in the prior art, an ion beam online variable beam diameter processing device and a beam diameter changing method thereof are provided. The present invention aims to overcome the problem of repeated switching of the vacuum chamber and the ion source during the existing ion beam processing, which reduces the processing efficiency, and realizes precise and stable control of the beam diameter changing process, thereby improving the processing accuracy and efficiency.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] An ion beam online variable beam diameter processing device comprises a base and a top cover, wherein the base and the top cover are both provided with a central through hole for the ion beam to pass through, the top cover is driven by a motor and rotatably arranged on one side of the central through hole of the base, a side of the base close to the top cover is provided with a plurality of circular holes evenly arranged along the edge of the central through hole, a side of the top cover close to the base is provided with a plurality of guide grooves, a plurality of aperture plates are provided between the base and the top cover, which are partially overlapped and arranged around the central through hole and enclosed to form an aperture hole for the ion beam to pass through, a guide post is provided on each of the different sides at both ends of the aperture plate, and one guide post is inserted and arranged in the circular hole, and the other guide post is slidably arranged in the guide groove, the aperture plate is in the shape of an arc strip and has arc shapes at both ends, and the number of the aperture plates is:

[0006] ,

[0007] In the above formula, is the number of aperture pieces, is the maximum radius of the aperture, is the minimum radius of the aperture, It is the outer arc radius of the arc strip.

[0008] Optionally, a first bearing is connected to the base, an inner ring of the first bearing is fixedly connected to the base, a transmission wheel driven by a motor is fixed to the outer ring of the first bearing, and the top cover is fixedly connected to the transmission wheel.

[0009] Optionally, the transmission wheel is a worm wheel, the base is further connected to a bottom shell, a motor is provided on the bottom shell, an output shaft of the motor is connected to a worm, and the worm is meshed with the worm wheel to form a worm gear assembly.

[0010] Optionally, a bracket is provided on the bottom shell, one end of the worm is mounted on the bracket via a second bearing, and the other end is connected to the output shaft of the motor via a coupling.

[0011] Optionally, the bracket is also provided with an encoder for detecting the actual rotation angle of the motor through the worm.

[0012] Optionally, the centers of the plurality of circular holes on the base are located on a circumference arranged concentrically with the center of the aperture hole, and the radius of the circumference is The size is:

[0013] ,

[0014] In the above formula, is the maximum radius of the aperture, is the minimum radius of the aperture; the inner arc radius and the outer arc radius of the arc strip are:

[0015] ,

[0016] ,

[0017] In the above formula, is the inner arc radius of the arc strip, is the maximum radius of the aperture, is the outer arc radius of the arc strip, is the radius of the circle where the centers of the multiple circular holes are located, and the center angle between the two guide pillars on the aperture plate is:

[0018] ,

[0019] In the above formula, It is the central angle between the two guide posts on the aperture plate.

[0020] Optionally, the aperture piece is made of molybdenum or a molybdenum alloy.

[0021] In addition, the present invention also provides a beam diameter changing method for the above-mentioned ion beam online beam diameter changing processing device, including two PID controllers based on an outer loop and an inner loop to perform beam diameter changing control: determining the corresponding reference beam current size based on the target aperture of the aperture hole according to the aperture aperture-beam current mapping relationship, in which the aperture aperture and the beam current size are positively correlated, obtaining the actual beam current size passing through the aperture hole, and calculating the beam current deviation between the actual beam current size and the reference beam current size E ; The beam error E The reference rotation angle is obtained by using the PID controller of the outer loop; the actual rotation angle of the motor used to drive the top cover to rotate is collected, and the angle deviation between the actual rotation angle and the reference rotation angle is calculated; the angle deviation is used to obtain a motor control signal by using the PID controller of the inner loop, and the motor is controlled to drive the top cover to rotate so as to drive the guide post of the aperture piece to slide in the guide groove to adjust the multiple aperture pieces to adjust the size of the aperture hole to the target aperture aperture.

[0022] Optionally, the beam error E When the reference rotation angle is obtained by using the outer loop PID controller, the control parameters of the PID controller are updated by using a fuzzy algorithm: E Calculate the beam error change rate Ec ; The beam error E , beam error change rate Ec As the input of the fuzzy algorithm, the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d As the output of the fuzzy algorithm, the fuzzy subset is {NB, NM, NS, ZE, PS, PM, PB}, and the domain is [-6, 6], where NB, NM, NS, ZE, PS, PM and PB are the elements in the fuzzy subset, representing large negative values, medium negative values, small negative values, zero values, small positive values, medium positive values ​​and large positive values ​​respectively. The beam error is converted into E , beam error change rate Ec Mapping obtains the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d The control parameters of the outer loop PID controller are updated according to the following formula:

[0023] ,

[0024] In the above formula, K p , K i , K d They are the proportional gain, integral gain and differential gain of the outer loop PID controller. K p0 , K i0 , K d0 are the standard values ​​of proportional gain, integral gain and differential gain of the outer loop PID controller, Δ K p , Δ K i and Δ K d They are the values ​​of proportional gain change, integral gain change, and differential gain change respectively.

[0025] Compared with the prior art, the present invention mainly has the following advantages:

[0026] 1. The device of the present invention comprises a base and a top cover, the top cover is driven by a motor and rotatably arranged on one side of the central through hole of the base, a plurality of circular holes evenly arranged along the edge of the central through hole are provided on one side of the base close to the top cover, a plurality of guide grooves are provided on one side of the top cover close to the base, a plurality of aperture pieces partially overlapped around the central through hole and enclosed to form an aperture hole are provided between the base and the top cover, a guide post is provided at each end of the aperture piece, one guide post is inserted and arranged in the circular hole, and the other guide post is slidably arranged in the guide groove, so that by driving the top cover to rotate by the motor, one end of the aperture piece can slide in the guide groove from By changing the degree of overlap of multiple aperture pieces and then changing the size of the aperture hole formed by the aperture to adjust the size of the ion beam removal function beam diameter, there is no need to close the ion source and then open the vacuum chamber to manually replace the ion aperture, thereby saving time and overcoming the problem of repeated opening and closing of the vacuum chamber and the ion source during existing ion beam processing that reduces processing efficiency. In addition, when adjusting the size of the ion beam removal function beam diameter, the relative position of the workpiece center and the tool center does not change, and there is no need to determine the relative position of the two centers again, thereby improving processing efficiency, achieving precise and stable control of the beam diameter variable process, and improving processing accuracy and efficiency.

[0027] 2. The present invention determines the number of aperture pieces through a calculation formula for the number of aperture pieces, which can drive the rotation normally while ensuring that the ion beam removal function presents a relatively good rotationally symmetric Gaussian distribution, taking into account the installation fit and the shape of the aperture hole, reducing the influence of the shape of the aperture hole on the removal function, thereby improving the accuracy of deterministic processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1It is a schematic diagram of the three-dimensional exploded structure of the key parts of the device of the embodiment of the present invention.

[0029] Figure 2 It is a schematic diagram of the installation front view of the base and the first bearing in an embodiment of the present invention.

[0030] Figure 3 It is a schematic diagram of the installation side view structure of the base and the first bearing in an embodiment of the present invention.

[0031] Figure 4 Schematic diagram of the three-dimensional structure of the aperture piece in the embodiment of the present invention.

[0032] Figure 5 Schematic diagram of structural parameters of the aperture piece in an embodiment of the present invention.

[0033] Figure 6 Schematic diagram of the driving structure of the device according to the embodiment of the present invention.

[0034] Figure 7 This is a simulation diagram of the removal function after the ion beam passes through a standard circular hole in an embodiment of the present invention.

[0035] Figure 8 This is a simulation diagram of the removal function after the ion beam passes through the multi-sided circular arc hole in an embodiment of the present invention.

[0036] Fig. 9 Schematic diagram of the control principle of variable beam diameter in an embodiment of the present invention.

[0037] Legend: 1. Base; 10. Center through hole; 11. Round hole; 2. Top cover; 21. Guide groove; 3. Aperture plate; 30. Aperture hole; 31. Guide column; 4. First bearing; 5. Transmission wheel; 6. Bottom shell; 61. Motor; 62. Worm; 621. Second bearing; 622. Coupling; 63. Bracket; 64. Encoder. DETAILED DESCRIPTION

[0038] like Figure 1As shown, the ion beam online variable beam diameter processing device of this embodiment includes a base 1 and a top cover 2, both the base 1 and the top cover 2 are provided with a central through hole 10 for the ion beam to pass through, the top cover 2 is driven by a motor 61 and is rotatably arranged on one side of the central through hole 10 of the base 1, the base 1 is provided with a plurality of circular holes 11 evenly arranged along the edge of the central through hole 10 on a side close to the top cover 2, a plurality of guide grooves 21 are provided on the side of the top cover 2 close to the base 1, a plurality of aperture plates 3 are provided between the base 1 and the top cover 2, the plurality of aperture plates 3 are partially overlappedly arranged around the central through hole 10 and enclose an aperture hole 30 for the ion beam to pass through, a guide post 31 is provided on different sides at both ends of the aperture plate 3, and one guide post 31 is inserted in the circular hole 11, and the other guide post 31 is slidably arranged in the guide groove 21. During ion beam processing, the ion beam online variable beam diameter processing device of this embodiment can be used to directly control the aperture of the aperture hole 30 to adjust the beam diameter of the ion beam removal function. Its working principle is as follows: the motor 61 drives the top cover 2, and the top cover 2 rotates while driving the rotation of the aperture plate 3. Since the guide post 31 at one end of the aperture plate 3 is inserted in the circular hole 11 and the guide post 31 at the other end is slidably arranged in the guide groove 21, the aperture hole 30 is driven to expand and contract. Due to the above-mentioned method of adjusting the beam diameter of the ion beam removal function, there is no need to close the ion source and then open the vacuum chamber to manually replace the ion aperture, which saves time. In addition, when adjusting the beam diameter of the ion beam removal function in this way, the relative position of the workpiece center and the tool center does not change, and the relative position of the two centers does not need to be determined again, which improves the processing efficiency.

[0039] It should be noted that the central through hole 10 is the physical channel of the aperture hole 30, so the aperture of the central through hole 10 should be greater than or equal to the maximum aperture diameter of the aperture hole 30. As an optional implementation, in order to meet the requirements of ion beam processing technology, the aperture of the central through hole 10 in this embodiment is 40 mm, and the aperture diameter of the aperture hole 30 is adjustable in the range of 1 to 40 mm.

[0040] In addition, there are 12 guide grooves 21 on the top cover 2 in this embodiment, and the direction of the guide grooves 21 is arranged along the radial direction of the central through hole 10 to realize the normal rotation of the aperture piece 3. In addition, the direction of the guide grooves 21 can also be designed to be arranged obliquely along the radial direction of the central through hole 10, which can also realize the normal rotation of the aperture piece 3.

[0041] In order to achieve stable rotation between the base 1 and the top cover 2, as Figure 2 and Figure 3 As shown, a first bearing 4 is connected to the base 1 , the inner ring of the first bearing 4 is fixedly connected to the base 1 , a transmission wheel 5 driven by a motor 61 is fixedly connected to the outer ring of the first bearing 4 , and the top cover 2 is fixedly connected to the transmission wheel 5 .

[0042] It should be noted that the motor 61 can drive the transmission wheel 5 in a desired driving manner as required, such as a worm gear, gear, belt, friction wheel, etc. For example, as an optional implementation, a worm gear assembly is used in this embodiment. Figure 6 As shown, the transmission wheel 5 in this embodiment is a worm wheel, and the base 1 is also connected to a bottom shell 6, on which a motor 61 is provided. The output shaft of the motor 61 is connected to a worm 62, and the worm 62 is meshed with the worm wheel to form a worm gear assembly.

[0043] The motor drives the worm to rotate, and the worm drives the worm wheel to rotate. The top cover drives the aperture piece to rotate while following the rotation of the worm wheel, thereby driving the aperture hole to expand and contract.

[0044] In order to fix the worm 62 and ensure the flexible rotation of the worm 62, as Figure 6 As shown, a bracket 63 is provided on the bottom shell 6 in this embodiment, one end of the worm 62 is mounted on the bracket 63 through a second bearing 621 , and the other end is connected to the output shaft of the motor 61 through a coupling 622 .

[0045] In addition, in order to facilitate the detection of the rotation angle of the motor 61, as an optional implementation, Figure 6 As shown, the bracket 63 in this embodiment is also provided with an encoder 64 for detecting the actual rotation angle of the motor 61 through the worm 62 . This structure cleverly utilizes the space outside the bracket 63 .

[0046] Since a guide post 31 is provided on each side of the two ends of the aperture piece 3, and one guide post 31 is inserted in the circular hole 11, and the other guide post 31 is slidably arranged in the guide groove 21, in order to prevent the rotation of the aperture pieces 3 from interfering with each other, as shown in FIG. Figure 2 As shown, the centers of the plurality of circular holes 11 on the base 1 in this embodiment are located on a circle arranged concentrically with the center of the aperture hole 30.

[0047] And the radius of the circle The size is:

[0048] ,

[0049] In the above formula, is the maximum radius of the aperture 30, is the minimum radius of the aperture 30; Figure 4 and Figure 5As shown, the aperture piece 3 in this embodiment is in an arc strip shape and has arc shapes at both ends. According to the aperture range requirements of the aperture hole 30, when the aperture reaches the maximum, the aperture piece 3 rotates outward to the maximum limit, and its inner arc is required to fit into a circle with the maximum aperture. In order to avoid that when the aperture piece 3 is shrunk to the minimum aperture, the edge of the central through hole 10 on the base 1 is not completely covered, resulting in additional beam passing through, the inner arc radius and the outer arc radius of the arc strip are:

[0050] ,

[0051] ,

[0052] In the above formula, is the inner arc radius of the arc strip, is the maximum radius of the aperture 30, is the outer arc radius of the arc strip, is the radius of the circle where the centers of the multiple circular holes 11 are located, and the central opening angle between the two guide pillars 31 on the aperture plate 3 is:

[0053] ,

[0054] In the above formula, is the central opening angle between the two guide pillars 31 on the aperture plate 3, such as Figure 5 shown.

[0055] The aperture hole 30 in this embodiment is a polygonal arc hole formed by partially overlapping and enclosing a plurality of aperture pieces 3 around the central through hole 10, so that the aperture hole 30 formed by the plurality of aperture pieces 2 surrounding and fitting is a polygonal arc hole rather than a circular hole, which will affect the shape of the ion beam removal function. Undoubtedly, the more aperture pieces 3 there are, the closer the fitted polygonal arc is to a circle, but too many aperture pieces 3 will cause problems with installation and fitting. In order to take into account both installation and fitting and the shape of the aperture hole 30, the number of aperture pieces 3 in this embodiment is:

[0056] ,

[0057] In the above formula, is the number of aperture blades 3, is the maximum radius of the aperture 30, is the minimum radius of the aperture hole 30. The ion beam removal function is generally a rotationally symmetric Gaussian distribution, which is the most ideal removal function for deterministic processing. In this embodiment, the number of aperture pieces 3 is determined by the above-mentioned calculation formula for the number of aperture pieces 3, which can drive the rotation normally while ensuring that the ion beam removal function presents a relatively good rotationally symmetric Gaussian distribution, taking into account the installation fit and the shape of the aperture hole 30, reducing the influence of the shape of the aperture hole 30 on the removal function, thereby improving the accuracy of deterministic processing. As an optional embodiment, in this embodiment, the aperture diameter of the aperture hole 30 is within an adjustable range of 1 to 40 mm. The number of aperture pieces 3 can be calculated by the above-mentioned calculation formula for the number of aperture pieces 3 to obtain n=12, Figure 7 This is the simulation diagram of the removal function after the ion beam passes through the standard circular hole. Figure 8 is a simulation diagram of the removal function after the ion beam passes through the polygonal arc hole in this embodiment, Figure 7 and Figure 8 By comparison, it can be seen that the shape of the removal function after the ion beam passes through the polygonal arc hole changes little, presenting a Gaussian distribution that is approximately rotationally symmetric, and can be used as an ideal removal function for deterministic processing.

[0058] As an optional implementation, the aperture piece 3 in this embodiment is made of molybdenum or molybdenum alloy. Since the aperture piece 3 will be bombarded by an ion beam with an ion energy of 500-1500eV during ion beam processing, in this embodiment, molybdenum metal (molybdenum or molybdenum alloy) with good stability, low thermal expansion coefficient and high melting point is selected as the material of the aperture piece 3, which can remain stable and not deformed under the high temperature of ion beam bombardment, thereby avoiding problems when the aperture piece rotates, and molybdenum metal (molybdenum or molybdenum alloy) has high density and specific grain structure, which can avoid the sputtering of material particles on the surface of the aperture piece when the ion beam bombards, thereby having a high service life and durability, and will not contaminate the ion source and the processed optical elements, while reducing the sputtering rate and avoiding deformation of the blade during processing, not only does it not pollute the optical elements and the ion source, but it can also avoid deformation caused by long-term bombardment of the ion beam, and ensure the normal operation of the variable beam diameter.

[0059] In addition, if Fig. 9 As shown, this embodiment also provides a beam diameter changing method for the above-mentioned ion beam online beam diameter changing processing device, including two PID controllers based on an outer loop and an inner loop to perform beam diameter changing control:

[0060] S1, determining the corresponding reference beam current size of the target aperture of the aperture hole 30 according to the aperture aperture-beam current mapping relationship, in which the aperture aperture and the beam current size are positively correlated, and a database of the aperture aperture-beam current mapping relationship can be established in advance based on the above relationship, or a numerical mapping function model thereof can be established;

[0061] S2, obtain the actual beam size passing through the aperture 30, such as Figure 8 As shown, as an optional implementation, in this embodiment, a Faraday cup is used to measure the actual beam size passing through the aperture 30. The aperture 30 in the device is moved to the center of the Faraday cup, and the actual beam size measured by the Faraday cup can be calculated. In addition, other methods can be used to measure the actual beam size as needed. The method of this embodiment does not depend on a specific actual beam size measurement method;

[0062] S3, calculate the beam current deviation between the actual beam current size and the reference beam current size E ;

[0063] S4, the beam error E The reference rotation angle is obtained by using the PID controller of the outer loop;

[0064] S5, collecting the actual rotation angle of the motor 61 for driving the top cover 2 to rotate. As an optional implementation, in this embodiment, the actual rotation angle of the motor 61 is measured by the encoder 64. In addition, other methods can be used to detect the actual rotation angle of the motor 61 as needed. The method of this embodiment does not depend on the specific actual rotation angle detection method;

[0065] S6, calculating the angle deviation between the actual rotation angle and the reference rotation angle;

[0066] S7, uses the PID controller of the inner ring to obtain the motor control signal based on the angle deviation, and controls the motor 61 to drive the top cover 2 to rotate so as to drive the guide post 31 of the aperture piece 3 to slide in the guide groove 21 to adjust the multiple aperture pieces 3 to adjust the size of the aperture hole 30 to the target aperture diameter.

[0067] As an optional implementation, Fig. 9 As shown, in this embodiment, the beam error E When the reference rotation angle is obtained by using the PID controller of the outer loop, the control parameters of the PID controller are updated by using a fuzzy algorithm through the fuzzy controller:

[0068] S4.1, according to the beam error E Calculate the beam error change rate Ec , Fig. 9 The differential link represented as "d / dt" in the figure is an optional implementation method, and the beam error change rate is Ec The beam error between two adjacent beams can be used. E The difference is divided by the previous beam error E The obtained value can also be expressed by other methods as needed. E The beam error change rate is replaced by the physical quantity of change EcUpdate the control parameters of the PID controller;

[0069] S4.2, the beam error E , beam error change rate Ec As the input of the fuzzy algorithm, the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d As the output of the fuzzy algorithm, the fuzzy subset used is {NB, NM, NS, ZE, PS, PM, PB}, and the domain is [-6, 6], where NB, NM, NS, ZE, PS, PM, and PB are elements in the fuzzy subset, representing large negative values, medium negative values, small negative values, zero values, small positive values, medium positive values, and large positive values, respectively;

[0070] S4.3, the beam error is converted into E , beam error change rate Ec Mapping obtains the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d The value of

[0071] S4.4, update the control parameters of the outer loop PID controller according to the following formula:

[0072] ,

[0073] In the above formula, K p , K i , K d They are the proportional gain, integral gain and differential gain of the outer loop PID controller. K p0 , K i0 , K d0 are the standard values ​​of proportional gain, integral gain and differential gain of the outer loop PID controller, Δ K p , Δ K i and Δ K d They are the values ​​of proportional gain change, integral gain change, and differential gain change respectively.

[0074] In this embodiment, in step S4.3, the beam error is converted into E , beam error change rate Ec Mapping obtains the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d When the value of is, the fuzzy rule tables used are shown in Table 1, Table 2 and Table 3 respectively.

[0075] Table 1: Δ K p Fuzzy rule table

[0076]

[0077] Table 2: Δ K i Fuzzy rule table

[0078]

[0079] Table 3: Δ K d Fuzzy rule table

[0080]

[0081] In Tables 1 to 3, NB, NM, NS, ZE, PS, PM and PB are elements in the fuzzy subsets, representing large negative values, medium negative values, small negative values, zero values, small positive values, medium positive values ​​and large positive values, respectively. NB, NM, NS, ZE, PS, PM and PB are elements in the fuzzy subsets, and the domain is [-6, 6]. It should be noted that the fuzzy algorithm and the fuzzy rule table used by the fuzzy algorithm to convert the beam error E , beam error change rate Ec Mapping obtains the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d The value of is an existing well-known method, so its implementation details are not described in detail here.

[0082] In summary, when the method of this embodiment is used for ion beam processing, the aperture of the diaphragm can be directly controlled by the online variable beam diameter device of the ion beam of this embodiment, and the beam diameter of the ion beam removal function can be adjusted. There is no need to close the ion source and then open the vacuum chamber to manually replace the ion diaphragm, which saves time. In addition, the relative position of the center of the workpiece and the center of the tool does not change, and there is no need to determine the relative position of the two centers again, which improves the processing efficiency. The double arc aperture piece of the online variable beam diameter device of the ion beam is made of molybdenum metal material, which has a very high melting point and can remain stable and not deformed at high temperatures under ion beam bombardment, thereby avoiding problems when the aperture piece rotates. It has high density and a specific grain structure, which can avoid the sputtering of material particles on the surface of the aperture piece when the ion beam bombards, thereby having a high service life and durability, and will not contaminate the ion source and the processed optical elements. In order to ensure that the removal function of the ion beam is the most ideal removal function for deterministic processing technology, 12 double arc aperture pieces are selected to form a hole, which can drive the rotation normally while ensuring that the ion beam removal function presents a relatively good rotationally symmetric Gaussian distribution.

[0083] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application can take the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the process Figure 1 A process or multiple processes and / or boxes Figure 1 These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including an instruction device, which implements the functions specified in the process. Figure 1 A process or multiple processes and / or boxes Figure 1These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the process in the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0084] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An ion beam online variable beam diameter processing device, characterized in that: The invention comprises a base (1) and a top cover (2), wherein both the base (1) and the top cover (2) are provided with a central through hole (10) for allowing an ion beam to pass through, the top cover (2) is driven by a motor (61) and is rotatably arranged on one side of the central through hole (10) of the base (1), the base (1) is provided with a plurality of circular holes (11) evenly arranged along the edge of the central through hole (10) on one side close to the top cover (2), and the top cover (2) is provided with a plurality of guide grooves (21) on one side close to the base (1). A plurality of aperture pieces (3) are provided between the base (1) and the top cover (2), which are partially overlapped and arranged around the central through hole (10) and enclose an aperture hole (30) through which the ion beam can pass. A guide column (31) is provided on different sides at both ends of the aperture piece (3), and one guide column (31) is inserted and arranged in the circular hole (11), and the other guide column (31) is slidably arranged in the guide groove (21). The aperture piece (3) is in the shape of an arc strip and has arc shapes at both ends. The number of the aperture pieces (3) is: ， In the above formula, is the number of aperture blades (3), is the maximum radius of the aperture (30), is the minimum radius of the aperture (30), It is the outer arc radius of the arc strip.

2. The ion beam online variable beam diameter processing device according to claim 1, characterized in that: A first bearing (4) is connected to the base (1), an inner ring of the first bearing (4) is fixedly connected to the base (1), a transmission wheel (5) driven by a motor (61) is fixed to the outer ring of the first bearing (4), and the top cover (2) is fixedly connected to the transmission wheel (5).

3. The ion beam online variable beam diameter processing device according to claim 2, characterized in that: The transmission wheel (5) is a worm wheel. The base (1) is also connected to a bottom shell (6). A motor (61) is provided on the bottom shell (6). The output shaft of the motor (61) is connected to a worm (62). The worm (62) meshes with the worm wheel to form a worm wheel assembly.

4. The ion beam online variable beam diameter processing device according to claim 3, characterized in that: A bracket (63) is provided on the bottom shell (6); one end of the worm (62) is mounted on the bracket (63) via a second bearing (621), and the other end is connected to the output shaft of the motor (61) via a coupling (622).

5. The ion beam online variable beam diameter processing device according to claim 4, characterized in that: The bracket (63) is also provided with an encoder (64) for detecting the actual rotation angle of the motor (61) via the worm (62).

6. The ion beam online variable beam diameter processing device according to claim 1, characterized in that: The centers of the multiple circular holes (11) on the base (1) are located on a circumference that is arranged concentrically with the center of the aperture hole (30), and the radius of the circumference is The size is: ， In the above formula, is the maximum radius of the aperture (30), is the minimum radius of the aperture (30); the inner arc radius and the outer arc radius of the arc strip are: ， ， In the above formula, is the inner arc radius of the arc strip, is the maximum radius of the aperture (30), is the outer arc radius of the arc strip, is the radius of the circle where the centers of the plurality of circular holes (11) are located, and the center opening angle between the two guide pillars (31) on the aperture plate (3) is: ， In the above formula, It is the central opening angle between the two guide pillars (31) on the aperture plate (3).

7. The ion beam online variable beam diameter processing device according to claim 1, characterized in that: The aperture piece (3) is made of molybdenum.

8. The ion beam online variable beam diameter processing device according to claim 1, characterized in that: The aperture piece (3) is made of molybdenum alloy.

9. A beam diameter changing method for an ion beam online beam diameter changing processing device according to any one of claims 1 to 8, characterized in that: The invention comprises two PID controllers based on an outer loop and an inner loop to perform variable beam diameter control: determining a corresponding reference beam current size according to a mapping relationship between an aperture aperture and a beam current based on a target aperture aperture of an aperture hole (30), wherein the aperture aperture and the beam current size are positively correlated in the aperture aperture-beam current mapping relationship, obtaining an actual beam current size passing through the aperture hole (30), and calculating a beam current deviation between the actual beam current size and the reference beam current size. E ; The beam error E The reference rotation angle is obtained by using the PID controller of the outer ring; the actual rotation angle of the motor (61) used to drive the top cover (2) to rotate is collected, and the angle deviation between the actual rotation angle and the reference rotation angle is calculated; the angle deviation is used to obtain a motor control signal by using the PID controller of the inner ring, and the motor (61) is controlled to drive the top cover (2) to rotate so as to drive the guide column (31) of the aperture piece (3) to slide in the guide groove (21) to adjust the size of the aperture hole (30) of the plurality of aperture pieces (3) to a target aperture aperture.

10. The beam diameter changing method according to claim 9, characterized in that: The beam error E When the reference rotation angle is obtained by using the outer loop PID controller, the control parameters of the PID controller are updated by using a fuzzy algorithm: E Calculate the beam error change rate Ec ; The beam error E , beam error change rate Ec As the input of the fuzzy algorithm, the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d As the output of the fuzzy algorithm, the fuzzy subset is {NB, NM, NS, ZE, PS, PM, PB}, and the domain is [-6, 6], where NB, NM, NS, ZE, PS, PM and PB are the elements in the fuzzy subset, representing large negative values, medium negative values, small negative values, zero values, small positive values, medium positive values ​​and large positive values ​​respectively. The beam error is converted into E , beam error change rate Ec Mapping obtains the proportional gain change Δ K p , integral gain change Δ K i , differential gain change Δ K d The control parameters of the outer loop PID controller are updated according to the following formula: ， In the above formula, K p , K i , K d They are the three control parameters of the outer loop PID controller: proportional gain, integral gain and differential gain. K p0 , K i0 , K d0 are the standard values ​​of proportional gain, integral gain and differential gain of the outer loop PID controller, Δ K p , Δ K i and Δ K d They are the values ​​of proportional gain change, integral gain change, and differential gain change respectively.

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