Multi-focus laser micro-nano manufacturing method and system

Abstract

The invention discloses a multi-focus laser micro-nano manufacturing method and system, and relates to the technical field of laser processing, and the method comprises the steps: analyzing SVG vector coding information of a processing pattern; an LCOS-SLM multi-focus array is obtained by adopting an annular segmentation algorithm; adjusting the size of the graph, carrying out discretization processing on the graph, and carrying out interval homogenization processing on coordinate points of the graph; dividing the uniformly dispersed graph into n processing areas, and grouping coordinate information by taking uniform distribution of focus positions as a principle to obtain a processing path; substituting the coordinate information of each partition into an annular segmentation algorithm to generate a holographic phase image set; and splicing parameters between the machining areas are calibrated, and multi-focus parallel machining is completed. The efficient laser parallel machining method is achieved, the efficiency and stability of a laser machining system and the machining uniformity of a curve structure can be improved, and an efficient and reliable solution is provided for the field of micro-nano machining.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and more particularly to a multi-focus laser micro-nano manufacturing method and system. Background Art

[0002] In traditional laser direct writing technology, the processing of complex structures usually relies on the method of point-by-point scanning of a single laser focus. This process is time-consuming and inefficient, posing significant challenges to the efficient processing of complex patterns. To improve processing efficiency, a method of multi-focus parallel processing has been proposed. The methods of generating multi-foci are mainly divided into two categories: one is to create a large-scale dot matrix through fixed optical components, which is suitable for batch processing of simple and consistent structures; the other is to use a spatial light modulator (SLM), which adjusts the spatial distribution of the light field to flexibly control the shape, number, and position of the foci in the multi-focus array, greatly enhancing the efficiency and adaptability of laser processing and having great application potential in the field of laser processing.

[0003] Currently, there have been many research reports describing laser processing systems using multi-focus technology. Such as multi-focus parallel marking equipment and multi-focus processing systems for semiconductor lasers. However, the method of generating multi-foci with parallel marking equipment relies on a galvanometer system, and the spot shape and distribution are preset and immutable, lacking processing flexibility. As for the multi-focus processing system of semiconductor lasers, although it can generate multi-foci, the number is limited, making it difficult to substantially improve the processing efficiency.

[0004] Therefore, how to provide a multi-focus laser micro-nano manufacturing method and system based on a liquid crystal on silicon spatial light modulator (LCOS-SLM) to improve the efficiency, stability, and uniformity of curve structure processing of the laser processing system is an urgent problem for those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a multi-focus laser micro-nano manufacturing method and system. Through the continuous dynamic loading of the holographic phase diagram of a liquid crystal on silicon spatial light modulator (LCOS-SLM), combined with the joint control of a three-dimensional translation stage and an optical path switch, an efficient laser parallel processing method is realized. The present invention can improve the efficiency, stability, and uniformity of curve structure processing of the laser processing system, providing an efficient and reliable solution for the micro-nano processing field.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A multi-focus laser micro-nano manufacturing method, comprising:

[0007] S1. Analyze the SVG vector coding information of the processing pattern and construct a graphic contour;

[0008] S2. Obtain the LCOS - SLM multi - focus array using the circular segmentation algorithm;

[0009] S3. Adjust the graphic size according to the processing requirements, discretize the graphic based on the minimum spot interval, and equalize the interval of the coordinate points of the graphic through the coordinate point equalization algorithm;

[0010] S4. Divide the uniformly discretized graphic into n processing regions of the same size. Group the coordinate information of each partition based on the principle of uniform distribution of the focus positions, and process the redundant points generated during grouping through the coordinate adaptation filling algorithm to obtain the processing path;

[0011] S5. Substitute the coordinate information of each partition into the circular segmentation algorithm to generate a holographic phase map set;

[0012] S6. Calibrate the stitching parameters between the processing regions. Complete the parallel processing of multiple foci by continuously and dynamically loading the holographic phase map set and jointly controlling the three - dimensional translation stage and the optical switch.

[0013] Preferably, analyze the SVG vector coding information of the processing pattern, including:

[0014] Obtain the coordinate information and the corresponding curve function by analyzing the tags in the SVG vector coding information, and substitute the coordinate information into the simulated curve function to construct the graphic contour.

[0015] Preferably, it further includes: Before processing, calibrate the light field modulation range and spot size in the optical system, and calibrate the displacement relationship between the displacement parameters in the phase map and the actual processing.

[0016] Preferably, before processing, calibrate the light field modulation range and spot size in the optical system, and calibrate the displacement relationship between the displacement parameters in the phase map and the actual processing, including:

[0017] Process multiple array structures through the LCOS - SLM, measure the sizes of the array structures in the actual light field multiple times and take the average value. Determine the displacement relationship between the displacement parameters in the phase map and the actual processing according to the proportional relationship between the size parameters and the array size in the actual light field;

[0018] Measure the size of the structure of single - point exposure, obtain that the diameter of the actually processed spot is d, set multi - focus arrays with different numbers of points, and determine that the maximum number of processing foci is M according to the array with the largest number of foci that can be processed under the maximum power max ;

[0019] Learn the minimum simulation unit in the numerical simulation that can be resolved through calibration experiments, the minimum processing region R min and the minimum number of processing regions n min depend on the minimum simulation unit that can be resolved;

[0020] Set the size of the single processing area as r, the number of processing areas as n, the minimum spot interval as Δd, and the number of focal points as M;

[0021] wherein, r ≥ r min 、n ≥ n min 、d / 4 ≤ Δd ≤ d / 2、M ≤ M max 。

[0022] Preferably, discretize the pattern according to the minimum spot interval, including:

[0023] S301. Based on the set single processing area size r, the number of processing areas n, and the minimum spot interval Δd, adjust the pattern width to r*sqrt(n), discretize each curve into coordinate points, sort all the coordinate points in the order of the line path, and generate an array of horizontal and vertical coordinates arranged in order.

[0024] S302. Detect whether the spacing between points in the horizontal and vertical coordinate array is uniform; when the spacing between any three points is less than Δd, then remove the middle coordinate point; when the spacing between any two points is greater than 3 / 2Δd, then add a coordinate point between the two points, and the intervals between the added point and the other two points are the same.

[0025] Preferably, the method for allocating processing areas and obtaining processing paths in S4 is:

[0026] S401. Make the whole pattern symmetric about the origin, and divide the pattern into n areas based on the set single processing area size r and the number of processing areas n in S2. The size of each area is the same and the coordinates are symmetric about the origin. The coordinates of the i-th area are expressed as (X i (l), Y i (l)), and the total number of partition coordinates is l;

[0027] S402. Based on the set number of focal points M, allocate the coordinates of each area into M groups. The coordinates of the i-th area are (X i1 (l), Y i1 (l))...(X iM (l), Y iM (l)).

[0028] Preferably, the process of multi-focal point parallel processing is:

[0029] S601. Process linear structures with a size of d l respectively through LCOS-SLM and a three-dimensional translation stage, and measure that the angles between the linear structures in the X and Y directions are θ x , θ y , then the lateral misalignment difference X l= tan(θ x )*d l , the vertical misalignment difference Y l = tan(θ y )*d l ;

[0030] S602. Determine the processing order between each area based on the set number n of processing areas;

[0031] S603. Calculate the coordinates (X, Y) corresponding to the center point of each area from the processing order between each area and the size of each area, recalculate (X, Y) according to the misalignment difference between each area to compensate for the misalignment relationship during splicing, and store the compensated coordinates in an array.

[0032] S604. Control the three-dimensional translation stage, the pure-phase spatial light modulator, and the optical switch in sequence to obtain the final processing structure.

[0033] Preferably, the process of S604 includes:

[0034] First, move the three-dimensional translation stage to the coordinates (X, Y) corresponding to the first area, dynamically load the phase map corresponding to the first area onto the pure-phase spatial light modulator, turn on the optical switch for single exposure for Tms, and after the single exposure ends, move the three-dimensional translation stage to the next area for processing until all areas are processed.

[0035] Preferably, a multi-focus laser micro-nano manufacturing system includes: a laser, a beam shaping and modulation module, a dichroic mirror, an objective lens, a three-dimensional moving platform, a sample stage, a camera, and a computer;

[0036] The beam shaping and modulation module, the dichroic mirror, and the objective lens are sequentially arranged in front of the laser emission port of the laser along the laser propagation direction, the laser transmitted from the objective lens is directly opposite to the sample stage, the sample stage is arranged on the three-dimensional moving platform, the three-dimensional moving platform is connected to the computer through a moving platform controller, the camera is used to capture the real-time processing status of the sample stage, and the camera is connected to the computer.

[0037] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a multi-focus laser micro-nano manufacturing method and system, including: S1, analyzing the SVG vector encoding information of the processing pattern and constructing a graphic contour; S2, obtaining an LCOS-SLM multi-focus array by using an annular segmentation algorithm; S3, adjusting the graphic size according to the processing requirements, discretizing the graphic according to the minimum spot interval, and equalizing the coordinate point interval of the graphic through a coordinate point equalization algorithm; S4, dividing the evenly discretized graphic into n processing regions of the same size, grouping the coordinate information of each partition based on the principle of uniform distribution of focus positions, and processing the redundant points generated during grouping through a coordinate adaptation filling algorithm to obtain a processing path; S5, substituting the coordinate information of each partition into the annular segmentation algorithm to generate a holographic phase map set; S6, calibrating the stitching parameters between the processing regions, continuously and dynamically loading the holographic phase map set, and jointly controlling a three-dimensional translation stage and an optical switch to complete the parallel processing of multiple foci.

[0038] The present invention has the following beneficial effects:

[0039] 1. The processing method of the present invention extracts the processing path by analyzing the SVG vector map encoding information, and can flexibly adjust the processing point interval and the size of the processing region according to the size characteristics of the expected processing structure, thereby improving the flexibility of the multi-focus laser processing path planning.

[0040] 2. The point coordinate equalization and coordinate adaptation filling algorithms proposed by the present invention avoid the exposure points generated due to uneven coordinate intervals and coordinate distributions, and greatly increase the uniformity of the processing structure line width.

[0041] 3. The annular phase segmentation algorithm proposed by the present invention can generate a multi-focus array with controllable positions and uniform energies, further improving the processing efficiency while ensuring the processing uniformity.

[0042] 4. The stitching compensation method between the processing regions proposed by the present invention can significantly improve the smoothness of the line connection between regions of a large-scale structure, providing an efficient and reliable solution for the micro-nano processing field. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0044] Figure 1 It is a schematic optical path diagram of a multi-focus laser micro-nano manufacturing system device provided by an embodiment of the present invention.

[0045] Figure 2 It is a flowchart of a multi - focus laser micro - nano manufacturing method provided by an embodiment of the present invention.

[0046] Figure 3 It is a generated multi - focus strip - shaped phase segmentation diagram provided by an embodiment of the present invention. Detailed implementation manners

[0047] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0048] An embodiment of the present invention discloses a multi - focus laser micro - nano manufacturing method, including:

[0049] S1. Analyze the SVG vector encoding information of the machining pattern, and construct the graphic contour; use the SVG vector diagram to quickly extract and plan the machining path;

[0050] S2. Obtain the LCOS - SLM multi - focus array by using the annular segmentation algorithm;

[0051] S3. Adjust the graphic size according to the machining requirements, discretize the graphic according to the minimum spot interval, and equalize the coordinate point interval of the graphic through the coordinate point equalization algorithm;

[0052] In the embodiment of the present invention, the graphic size is adjusted according to the machining requirements, the graphic is discretized with Δd, the uniformity of the coordinate interval of the discrete points is detected, and the coordinate point interval is equalized through the point coordinate equalization algorithm;

[0053] S4. Divide the evenly - discretized graphic into n machining areas of the same size. Based on the number of foci M, group the coordinate information of each partition according to the principle of uniform distribution of focus positions, divide it into M groups, and process the redundant points generated during grouping through the coordinate adaptation filling algorithm to obtain the machining path; finally, each partition contains M machining paths;

[0054] S5. Substitute the coordinate information of each partition into the annular segmentation algorithm to generate a holographic phase map set;

[0055] S6. Calibrate the splicing parameters between the machining areas, and complete the entire multi - focus parallel machining through the continuous dynamic loading of the LCOS - SLM holographic phase map and the joint control of the three - dimensional translation stage and the optical switch.

[0056] Specifically, analyzing the SVG vector encoding information of the machining pattern includes:

[0057] By parsing the <path>The label obtains coordinate information and the corresponding curve function, substitutes the coordinate information into the simulated curve function, and constructs a graphic contour.

[0058] The SVG vector encoding information includes coordinate information and curve function information.

[0059] Specifically, in S2, it further includes: Before processing, calibrate the light field modulation range and spot size in the optical system, and calibrate the displacement relationship between the displacement parameters in the phase diagram and the actual processing.

[0060] Specifically, before processing, calibrate the light field modulation range and spot size in the optical system, and calibrate the displacement relationship between the displacement parameters in the phase diagram and the actual processing, including:

[0061] S201. Set the size parameter of the multi - focus array as b, process multiple array structures through LCOS - SLM, measure the size of the array structure in the actual light field multiple times and take the average value, and determine the displacement relationship between the displacement parameters in the phase diagram and the actual processing according to the proportional relationship between the size parameter b and the array size in the actual light field;

[0062] S202. Measure the structure size of single - point exposure, obtain that the diameter of the actually processed spot is d, set multi - focus arrays with different numbers of points, and determine that the maximum number of processing foci is M according to the array with the largest number of foci that can be processed under the maximum power max ;

[0063] S203. Through calibration experiments, obtain the minimum simulation unit, the minimum processing area R min and the minimum number of processing areas n min in the numerically simulated values that can be resolved; (the interval between different lines must be greater than the minimum simulation unit)

[0064] S204. Set the size of a single - time processing area as r, the number of processing areas as n, the minimum spot interval as Δd, and the number of foci as M;

[0065] wherein, r ≥ r min 、n ≥ n min 、d / 4 ≤ Δd ≤ d / 2、M ≤ M max 。

[0066] Specifically, discretize the graph according to the minimum spot interval, including:

[0067] S301. Based on the set single - processing area size \(r\), the number of processing areas \(n\), and the minimum spot interval \(\Delta d\), adjust the graphic width to \(r\times\sqrt{n}\). By means of numerical interpolation, discretize each curve into coordinate points, sort all the coordinate points in the order of the line path, and generate an array of horizontal and vertical coordinates arranged in sequence. The array of horizontal and vertical coordinates is the array of abscissa \(X(l)\) and ordinate \(Y(l)\), where \(l\) represents the number of coordinate points.

[0068] S302. Detect whether the spacing between points in the array of horizontal and vertical coordinates is uniform; when the spacing between any three points is less than \(\Delta d\), then remove the middle coordinate point; when the spacing between any two points is greater than \(\frac{3}{2}\Delta d\), then add a coordinate point between the two points, and the intervals between the added point and the other two points are the same.

[0069] Specifically, the method for allocating processing areas and obtaining processing paths in S4 is as follows:

[0070] S401. Make the whole graphic symmetric about the origin, and based on the set single - processing area size \(r\) and the number of processing areas \(n\) in S2, divide the graphic into \(n\) areas. The size of each area is the same and the coordinates are all symmetric about the origin. The coordinates of the \(i\) - th area are expressed as \((X i (l), Y i (l))\), and the total number of partition coordinates is \(l\).

[0071] S402. Based on the set number of foci \(M\), allocate the coordinates of each area into \(M\) groups. The coordinates of the \(i\) - th area are \((X i1 (l), Y i1 (l))\cdots(X iM (l), Y iM (l))\). Among them, the interval between each focus is \(\frac{l}{M}\) units; if the total number of coordinates \(l\) of area \(i\) is not an integer multiple of \(M\), then add coordinate points outside the modulation range until the number of coordinates is an integer multiple of \(M\) and then re - allocate the coordinates.

[0072] Specifically, the specific operation steps for generating the holographic phase - diagram sequence in S5 are as follows:

[0073] S501. Divide the rear - aperture plane into \(N\) annular regions with the diameter \(D\) of the rear - aperture plane of the objective lens, and further divide each annular region into \(M\) smaller annular regions, and the radial intervals between the regions are equal.

[0074] S502. Substitute the coordinates of each partition into the phase expression:

[0075]

[0076] where \(\lambda\) is the laser wavelength, \(NA\) is the numerical aperture of the used objective lens, \(n t is the refractive index of the objective lens, R is the maximum radius of the rear aperture plane of the objective lens, x0 and y0 are the orthogonal coordinates of the rear aperture plane of the objective lens, where X i (l) and Y i (l) are the relative displacement components relative to the original focus of the objective lens in the x and y directions on the focal plane. The phase information is filled into the corresponding positions of each pixel of the liquid crystal plate, and a series of holographic phase diagrams that can simultaneously generate 32 focal points are obtained.

[0077] Specifically, the process of multi-focus parallel processing is as follows:

[0078] S601. Linear structures with a size of d l are processed through the LCOS-SLM and the three-dimensional translation stage respectively. The included angles between the linear structures in the X and Y directions are measured as θ x , θ y . Then, the lateral misalignment difference X l = tan(θ x ) * d l , and the longitudinal misalignment difference Y l = tan(θ y ) * d l ;

[0079] S602. Based on the set number n of processing regions, determine the processing order between the regions.

[0080] Specifically, it includes: listing the processing regions as a matrix of size sqrt(n) * sqrt(n), numbering the elements of the matrix through the total number n of regions. The odd rows of the matrix are assigned numbers in the index order, and the even rows are assigned numbers in the reverse index order. Then, the processing order between the regions is consistent with the matrix element numbers;

[0081] S603. Obtain the current position (x, y) of the three-dimensional translation stage. Calculate the coordinates (X, Y) corresponding to the center point of each region from the processing order between the regions and the size of each region. Recalculate (X, Y) according to the misalignment differences between the regions to compensate for the misalignment relationship during splicing, and store the compensated coordinates in an array.

[0082] Specifically, it includes:

[0083] The current (x, y) represents the position of the first region. From the processing order between the regions, the relative positions of other regions and the first region can be known. Other regions are relatively X r units horizontally and Y r units vertically relative to the first region. The size of each region is r. Then, the coordinates of the i-th region are expressed as (X i , Y i ) = ((x + X r *r), (y + Y r *r)), and based on this, the coordinates corresponding to the center point of each region are calculated as (X, Y). Due to the misalignment difference between regions, the horizontal misalignment difference X l is tan(θ x ) * d l , and the vertical misalignment difference Y l is tan(θ y ) * d l . Then, (X, Y) is recalculated. After misalignment compensation, the coordinates of the i-th region (X i , Y i ) = ((x + (X r + X l ) * r), (y + (Y r + Y l ) * r)), and the compensated coordinates are stored in an array.

[0084] S604. Control the three-dimensional translation stage, pure-phase spatial light modulator, and optical switch in sequence to obtain the final processed structure.

[0085] Specifically, the process of S604 includes:

[0086] First, move the three-dimensional translation stage to the coordinates (X, Y) corresponding to the first region, dynamically load the phase map corresponding to the first region onto the pure-phase spatial light modulator, turn on the optical switch for single exposure for T ms, and after the single exposure ends, move the three-dimensional translation stage to the next region for processing until all regions are processed.

[0087] The embodiment of the present invention proposes a multi-focus laser micro-nano manufacturing method. First, the rapid extraction and planning of processing point coordinates are realized by using Scalable Vector Graphics (SVG). Subsequently, the displacement relationship between the displacement parameters in the multi-focus array calibration phase map generated based on the annular phase segmentation algorithm and the actual processing is established. Further, the discretized processing path coordinates are determined, and the point spacing uniformity and coordinate adaptation filling algorithm are proposed to optimize the processing uniformity. Finally, through the continuous dynamic loading of the LCOS-SLM holographic phase map, combined with the joint control of the three-dimensional translation stage and the optical path switch, an efficient laser parallel processing method is realized. The embodiment of the present invention can improve the efficiency, stability of the laser processing system, and the uniformity of curve structure processing.

[0088] In a specific embodiment of the present invention, a multi-focus laser micro-nano manufacturing system, as Figure 1 shown, includes: a laser (LASER), a beam shaping and modulation module, a dichroic mirror (DM), an objective lens (OL), a three-dimensional moving platform (PI), a sample stage (Sample), a camera (CMOS), and a computer;

[0089] A beam shaping and modulation module, a dichroic mirror and an objective lens are sequentially arranged in front of the laser emission port of the laser along the laser propagation direction. The laser emitted from the objective lens is directly opposite to the sample stage. The sample stage is arranged on a three-dimensional moving platform. The three-dimensional moving platform is connected to a computer through a moving platform controller. The camera is used to capture the real-time processing status of the sample stage and is arranged at a position where the real-time processing status of the sample stage can be accurately captured. The camera is connected to the computer.

[0090] Specifically, the beam shaping and modulation module modulates and shapes the incident beam from the laser and adjusts the output power; the dichroic mirror deflects and reflects the laser from the beam shaping and modulation module to the objective lens; the objective lens focuses the laser on the material placed on the sample stage; the three-dimensional moving platform is used to adjust the position of the sample stage to process each processing area; the moving platform controller is used to control the displacement of the three-dimensional moving platform in three directions; the computer is used to control the entire processing system and obtain the real-time processing process monitored by the camera.

[0091] Specifically, the specific content of the beam shaping and modulation module is that the laser is first adjusted by a half-wave plate (HWP) and a Glan prism (GP) along the propagation direction; then filtered and collimated through a 4f system composed of L1, SLF and L2 to improve the beam quality; then passed through a second half-wave plate (HWP) to align the polarization direction of the beam with the working direction of the liquid crystal panel of the pure phase spatial light modulator (SLM); a mechanical switch (MS) is used to precisely control the exposure time of the light source.

[0092] In the embodiment of the present invention, the laser passes through a reflecting mirror (R1) and is reflected to a dichroic mirror (DM) after passing through the beam shaping and modulation module. A small hole aperture (Iris) is used to suppress the zero-order light spot caused by the pixelation of the spatial light modulator. After being reflected by the DM, the modulated laser beam is precisely focused into the photoresist through an objective lens (OL) with a high numerical aperture. The field of view is illuminated by a protection lamp (LS), and the illumination light is reflected into the camera (CMOS) through a reflecting mirror (RM). The camera is used to monitor the manufacturing process in real time.

[0093] In the embodiment of the present invention, the first half-wave plate is a half-wave plate that can transmit light with a wavelength of 700 - 1000 nm, and the second half-wave plate is a half-wave plate that can transmit light with a wavelength of 650 - 1000 nm. The dichroic mirror has a high reflectivity for light with a wavelength of 520 - 800 nm and a high transmittance for light in other wavelength bands. A photoresist DETC is placed on the sample stage. The objective lens is an oil immersion lens with 100X NA1.25.

[0094] In a specific embodiment of the present invention, the embodiment of the present invention also provides a multi-focus laser micro-nano manufacturing method based on a liquid crystal on silicon spatial light modulator (LCOS-SLM), as Figure 2 As shown, it includes the following steps:

[0095] S1. Parse the SVG vector graphic encoding information of the pentagram through a computer to identify <path>Extract the vector path of the pentagram label and construct the outline of the pentagram;

[0096] S2. Use the annular segmentation method to obtain a 3×3 multi-focus array, thereby calibrating the light field modulation range and spot size, calibrating the correspondence between the graph distribution of numerical simulation and the actual light field distribution, and setting the size of a single processing area to 4.7 μm, the number of processing areas to 4, the minimum spot interval to 0.2 units, and the number of foci to 32;

[0097] S3. Adjust the size of the pentagram to 60×60 units, discretize the graph according to the minimum spot interval Δd = 0.2, and detect the uniformity of the discrete point intervals;

[0098] Specifically, detecting the uniformity of the discrete point intervals includes: calculating the distances between adjacent coordinate points through the distance formula between points, calculating the average value and standard deviation of these distances, and using the ratio of the standard deviation to the average value to evaluate the uniformity. The smaller the ratio, the more uniform the distribution of points. When the ratio of the standard deviation to the average value is less than the minimum spot interval Δd, the distribution is considered uniform. When the distribution is not uniform, perform coordinate homogenization processing;

[0099] S4. Divide the pentagram into 4 regions, distribute the coordinate information within each partition according to the number of spots 32. There are extra point coordinates in the second partition, resulting in uneven numbers of coordinates corresponding to each spot. Then, add the corresponding number of coordinates outside the modulation range and redistribute them. Finally, each of the four partitions contains 32 processing paths;

[0100] S5. As Figure 3 shown, substitute the coordinate information allocated for each partition into the annular phase segmentation algorithm to generate a sequence of holographic phase diagrams;

[0101] S6. Processing preparation: Determine the processing order in a bow shape between regions, set the laser entrance pupil power to 600 mw for processing 32 points, the exposure time of a single phase diagram to 17 ms, extract a small amount of photoresist DETC onto a clean glass slide, and fix the glass slide on the sample stage, i.e., above the objective lens.

[0102] Processing stage: The laser emits a femtosecond laser beam with a wavelength of 800 nm and is incident on the beam shaping and modulation module for modulation and shaping. The modulated beam is reflected by a mirror and a spatial light modulator to a dichroic mirror, and is focused onto the photoresist on the sample stage under the action of the objective lens.

[0103] The cross structure with a size of 4.7 μm is processed by the LCOS-SLM and the translation stage respectively. Measure the angles between the crosses in the X and Y directions, and calculate that the lateral misalignment between regions is 0.12 μm and the longitudinal misalignment is 0.14 μm. Obtain the position (x, y) of the current three-dimensional translation stage, and calculate the corresponding (X, Y) coordinates of the center point of each region according to the misalignment difference and the processing sequence. First, move the translation stage to the (X, Y) coordinates corresponding to the first region, dynamically load the phase diagram corresponding to the first region to the pure-phase spatial light modulator, turn on the optical switch for single exposure for Tms (T = the number of phase diagrams * 17 ms). After the single exposure is completed, move the translation stage to the next region for processing until all regions are processed, and the final processed structure can be obtained.

[0104] In the embodiment of the present invention, in S1, the SVG vector coding information of the pattern to be processed is parsed. The coding information includes coordinate information and curve function information, and the graphic contour is constructed by parsing the coding information.

[0105] In the embodiment of the present invention, the parameter calibration process in S2 is as follows:

[0106] S201. Process three groups of 3*3 multi-focus arrays with 30 units in the optical field, measure the sizes of the three groups of array structures, and obtain the final average size of 4.7 μm. Since 30 unit lengths correspond to 4.7 μm, the displacement relationship between the displacement parameter in the phase diagram and the actual processing is calculated according to the ratio: l (one unit length) = 4.7 / 30 (μm);

[0107] S202. Measure the size of the structure of single-point exposure, and obtain that the actual processed spot diameter is 62.4 nm. According to the maximum power of 600 mw, process dot matrices with M = 2, 4, 16, 25, 32, and 36 respectively, and determine that the maximum number of focal points is 32;

[0108] S203. Through the calibration experiment, know the minimum unit in the numerical simulation that can be distinguished, the minimum processing area R min and the minimum number of processing areas n min depend on the minimum simulation unit that can be distinguished (the interval between different lines must be greater than the minimum simulation unit).

[0109] In the embodiment of the present invention, in S3, the pattern is uniformly discretized, and the specific operation steps are as follows:

[0110] S301. Based on r, n, and Δd set in S2, adjust the width of the pentagram to 60*60 units. By the numerical interpolation method, each curve is discretized into coordinate points, and all point coordinates are sorted according to the processing path to generate arrays of the abscissa X(l) and ordinate Y(l) arranged in sequence, where l represents the number of coordinate points.

[0111] S302. Detect whether the distances between points in the XY array are uniform. When the distances between any three points are all less than 0.2, eliminate the middle coordinate point. When the distance between any two points is greater than 0.3, add a coordinate point between the two points, and the added point has the same interval as the other two points.

[0112] In the embodiment of the present invention, the specific method for allocating the processing area and the processing path in S4 is as follows:

[0113] S401. Make the pentagram as a whole symmetric about the origin, and divide the graph into 4 regions based on r and n set in S2. The size of each region is the same and the coordinates are symmetric about the origin. The coordinates of the i-th region are (X i (l), Y i (l));

[0114] S402. Based on M set in S2, allocate the coordinates of each region into 32 groups. The coordinates of the i-th region are (X i1 (l), Y i1 (l))...(X iM (l), Y iM (l)). If the number of coordinate points in region i is not an integer multiple of 32, add coordinate points outside the modulation range until the number of coordinate points is an integer multiple of 32 and re-allocate the coordinates.

[0115] In the embodiment of the present invention, the specific operation steps for generating the holographic phase diagram sequence in S5 are as follows:

[0116] S501. Divide the rear aperture plane into 40 annular regions with the diameter D of the rear aperture plane of the objective lens, and further divide each annular region into 32 smaller annular regions; since the energy of the central unit pixel of the SLM liquid crystal panel is stronger than that of the edge, by dividing the annular region, the central area is smaller and the edge area is larger, so as to balance the energy distribution problem between the foci and greatly improve the uniformity of the light spots;

[0117] S502. Substitute the coordinates of each partition into the phase expression:

[0118]

[0119] where λ is the laser wavelength, NA is the numerical aperture of the objective lens used, n t is the refractive index of the objective lens, R is the maximum radius of the rear aperture plane of the objective lens, x0 and y0 are the orthogonal coordinates of the rear aperture plane of the objective lens, where X i (l) and Y i (l) are the relative displacement components in the x and y directions of the focal plane relative to the original focus of the objective lens. Fill the phase information into the corresponding positions of each pixel of the liquid crystal panel, and a series of holographic phase diagrams capable of generating 32 foci simultaneously are obtained.

[0120] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0121] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.< / path> < / path>

Claims

1. A multi-focus laser micro-nano manufacturing method, characterized in that: include: S1, parsing the SVG vector encoding information of the processing pattern and constructing the graphic outline; S2, using the annular segmentation algorithm to obtain the LCOS-SLM multi-focus array; S3, adjust the size of the graphics according to the processing requirements, discretize the graphics according to the minimum interval of the light spot, and evenly process the coordinate point interval of the graphics through the coordinate point uniformity algorithm; S4, dividing the uniformly discretized graphics into n processing areas of equal size, grouping the coordinate information of each partition based on the principle of uniform distribution of the focus position, processing the redundant points generated during grouping through a coordinate adaptation filling algorithm, and obtaining a processing path; S5, substituting the coordinate information of each partition into the ring segmentation algorithm to generate a holographic phase atlas; S6. Calibrate the stitching parameters between the processing areas, and complete the parallel processing of multiple focuses by continuously and dynamically loading the holographic phase atlas and jointly controlling the three-dimensional translation stage and the optical switch.

2. A multi-focus laser micro-nano manufacturing method according to claim 1, characterized in that: Parse the SVG vector encoding information of the processing pattern, including: The coordinate information and the corresponding curve function are obtained by parsing the tags in the SVG vector encoding information, and the coordinate information is substituted into the simulated curve function to construct the graphic outline.

3. The multi-focus laser micro-nano manufacturing method according to claim 1, characterized in that: Also includes: Before processing, the light field modulation range and spot size are calibrated in the optical system, and the relationship between the displacement parameters in the phase diagram and the displacement in actual processing is calibrated.

4. The multi-focus laser micro-nano manufacturing method according to claim 3, characterized in that: Before processing, the light field modulation range and spot size are calibrated in the optical system, and the relationship between the displacement parameters in the phase diagram and the displacement in the actual processing is calibrated, including: Multiple array structures are processed by LCOS-SLM, the size of the array structure in the actual light field is measured multiple times and the average value is taken. According to the proportional relationship between the size parameter and the array size in the actual light field, the relationship between the displacement parameter in the phase diagram and the displacement in the actual processing is determined; Measure the structural dimensions of single-point exposure, and obtain the actual processed spot diameter d. Set up multi-focus arrays with different numbers of points, and determine the maximum number of processing focuses as M based on the array with the largest number of focuses that can be processed at the maximum power. max ; Through the calibration experiment, we know that the smallest simulation unit in the numerical simulation that can be distinguished, the minimum processing area R min and the minimum number of processing areas n min Depends on the smallest analog unit that can be resolved; Set the size of a single processing area to r, the number of processing areas to n, the minimum interval of the light spot to Δd, and the number of focal spots to M; Where r ≥ r min , n≥n min d / 4≤Δd≤d / 2, M≤M max .

5. The multi-focus laser micro-nano manufacturing method according to claim 4, characterized in that: Discretize the graphics according to the minimum interval of the light spot, including: S301, based on the set single processing area size r, the number of processing areas n and the minimum spot interval Δd, the graphic width is adjusted to r*sqrt(n), each curve is discretized into coordinate points, all coordinate points are sorted according to the line path order, and a sequentially arranged horizontal and vertical coordinate array is generated; S302, check whether the spacing between the points in the horizontal and vertical coordinate arrays is uniform; when the spacing between any three points is less than Δd, the middle coordinate point is removed; when the spacing between any two points is greater than 3 / 2Δd, a coordinate point is added between the two points, and the spacing between the added point and the remaining two points is consistent.

6. The multi-focus laser micro-nano manufacturing method according to claim 4, characterized in that: The method of allocating processing areas and obtaining processing paths in S4 is: S401, make the whole figure symmetrical about the origin, and divide the figure into n areas based on the single processing area size r and the number of processing areas n set in S2, each area has the same size and the coordinates are symmetrical about the origin, and the coordinates of the i-th area are expressed as (X i (l), Y i (l)), the total number of partition coordinates is l; S402: Based on the set number of focal points M, the coordinates of each region are divided into M groups, and the coordinates of the i-th region are (X i1 (l), Y i1 (l))...(X iM (l), Y iM (l)).

7. The multi-focus laser micro-nano manufacturing method according to claim 4, characterized in that: The process of multi-focus parallel processing is: S601, through LCOS-SLM and three-dimensional translation stage, the size of each l The linear structure is measured, and the angles between the linear structures in the X and Y directions are θ x ,θ y , then the horizontal displacement difference of each area is X l =tan(θ x )*d l , longitudinal misalignment difference Y l =tan(θ y )*d l ; S602, determining the processing order between the regions based on the set number of processing regions n; S603, the coordinates corresponding to the center point of each area are calculated as (X, Y) according to the processing order between the areas and the size of the areas, and the (X, Y) is recalculated according to the misalignment difference between the areas to compensate for the misalignment relationship between the splicing, and the compensated coordinates are stored in an array; S604, sequentially controlling the three-dimensional translation stage, the pure phase spatial light modulator, and the optical switch to obtain a final processed structure.

8. The multi-focus laser micro-nano manufacturing method according to claim 7, characterized in that: The S604 process includes: First, move the 3D translation stage to the coordinates (X, Y) corresponding to the first area, dynamically load the phase map corresponding to the first area to the pure phase spatial light modulator, turn on the optical switch for a single exposure Tms, and after the single exposure, move the 3D translation stage to the next area for processing until all areas are processed.

9. A multi-focus laser micro-nano manufacturing system, using a multi-focus laser micro-nano manufacturing method according to any one of claims 1 to 8, characterized in that: include: Laser, beam shaping modulation module, dichroic mirror, objective lens, three-dimensional moving platform, sample stage, camera and computer; A beam shaping modulation module, a dichroic mirror and an objective lens are arranged in sequence in front of the laser emission port of the laser along the laser propagation direction. The laser emitted from the objective lens is directly facing the sample stage. The sample stage is arranged on a three-dimensional mobile platform. The three-dimensional mobile platform is connected to a computer through a mobile platform controller. The camera is used to capture the real-time processing status of the sample stage, and the camera is connected to the computer.

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