Laser processing device and laser processing method

Abstract

The present invention proposes a laser processing device and a laser processing method, which belong to the field of laser processing. The laser processing device includes: a laser shaping module, which is used to obtain a first pulse laser, and polarization modulate the first pulse laser according to a preset phase diagram, so that the linear polarization directions of the first pulse laser passing through the gray area of ​​the phase diagram and the part passing through the white area of ​​the phase diagram are perpendicular to each other, so as to obtain a second pulse laser; a polarization filtering module, which is used to polarization filter the second pulse laser, and obtain a third pulse laser with a light spot of a specified pattern, so as to process the surface to be processed by the third pulse laser. The laser processing device generates a specified pattern directly on the processing surface without the need for a mask, thereby improving the processing efficiency.

Description

Technical Field

[0001] The present invention relates to the field of laser processing, and in particular to a laser processing device and a laser processing method. Background Art

[0002] Micro-nano processing, especially processing at the nanoscale, is one of the important driving forces for the advancement of modern science and technology. Among them, the processing methods of micro-nanoscale metamaterials with unit period and characteristic size properties have attracted widespread attention. However, surface micro-nanostructure materials with special functions generally have the problems of low processing efficiency and high processing cost.

[0003] Electron beam lithography can achieve maskless direct writing of surface microstructures, with extremely high design freedom and processing accuracy, but the processing efficiency is low, making it difficult to put this method into large-scale production applications. Ultraviolet, extreme ultraviolet lithography and nanoimprinting can achieve the preparation of large-area micro-nano structures to a certain extent, but their processing accuracy is highly dependent on equipment and masks, and there are problems such as alignment and splicing and high equipment costs, which have prevented large-scale application. Summary of the invention

[0004] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0005] In view of the above problems, the embodiments of the present application propose a laser processing device and a laser processing method, which do not require the use of a mask and have high processing efficiency.

[0006] According to the first aspect of the present application, a laser processing device is proposed, which includes: a laser shaping module, used to obtain a first pulse laser, and polarization modulate the first pulse laser according to a preset phase diagram, so that the linear polarization directions of the first pulse laser passing through the gray area of ​​the phase diagram and the white area of ​​the phase diagram are perpendicular to each other, so as to obtain a second pulse laser; a polarization filtering module, used to polarization filter the second pulse laser, so as to obtain a third pulse laser with a light spot of a specified pattern, so as to process the surface to be processed by the third pulse laser.

[0007] According to the laser processing device of the first aspect of the present application, a prescribed pattern is generated on the surface to be processed by processing the surface to be processed using a third pulse laser with a spot of a prescribed pattern, without requiring a mask and with high processing efficiency.

[0008] In some embodiments, the laser processing device also includes: a laser input module, which is used to generate the first pulse laser and output the first pulse laser to the laser shaping module; wherein the first pulse laser is a picosecond pulse laser or a femtosecond pulse laser, and the energy distribution of the light spot generated by the first pulse laser satisfies a Gaussian distribution or a flat-top distribution.

[0009] In some embodiments, the laser input module includes a laser light source assembly, which is used to generate an original pulsed laser, and a laser output assembly, which is used to collimate and output the first pulsed laser; the laser input module also includes at least one of the following: an energy regulation assembly, which is used to regulate the energy of the original pulsed laser; and a laser beam expansion assembly, which is used to expand the original pulsed laser.

[0010] In some embodiments, the laser shaping module includes a polarization adjustment component and a spatial light modulator: the polarization adjustment component is used to modulate the first pulse laser into linear polarized light with a specified polarization direction, and output the modulated linear polarized light to the spatial light modulator; the spatial light modulator is used to perform pixel-by-pixel polarization modulation on the linear polarized light according to the phase diagram, so that the linear polarization directions of the part of the linear polarized light passing through the gray area of ​​the phase diagram and the part of the linear polarized light passing through the white area of ​​the phase diagram are perpendicular to each other.

[0011] In some embodiments, the phase map is a phase map of edge grayscale gradient, and a gradient curve corresponding to the edge grayscale gradient satisfies a prescribed function.

[0012] In some embodiments, the polarization filtering module includes a quarter wave plate and a polarizer, which are used to modulate the quarter wave plate and the polarizer according to the polarization angle of the second pulse laser to perform polarization filtering on the second pulse laser to obtain the third pulse laser with a spot of a specified pattern.

[0013] In some embodiments, the polarization filtering module includes a polarization selection component, which modulates the polarization of the third pulse laser according to the processing requirements of the surface to be processed, and modulates the third pulse laser into linearly polarized light or circularly polarized light.

[0014] In some embodiments, the laser processing device also includes a processing module for using the third pulse laser to process the surface to be processed, and the processing module includes a displacement component and a focusing component; the focusing component is used to shrink the third pulse laser and focus it to the surface to be processed according to the processing requirements.

[0015] In some embodiments, the displacement module is used to move the processing spot generated by the third pulse laser on the surface to be processed and the surface to be processed in a predetermined moving manner.

[0016] According to the second aspect of the present application, a laser processing method is proposed, comprising: injecting a linearly polarized first pulse laser with a specified polarization direction into a spatial light modulator; loading a specified phase map on the spatial light modulator; according to the phase map, adjusting the polarization direction of the first pulse laser pixel by pixel in the spatial light modulator, so that the linear polarization direction of the first pulse laser passing through the gray area of ​​the phase map and the linear polarization direction of the first pulse laser passing through the white area of ​​the phase map are perpendicular to each other, thereby obtaining a second pulse laser; performing polarization filtering on the second pulse laser, and shaping the second pulse laser into a third pulse laser with a specified pattern of light spots; focusing the third pulse laser onto a surface to be processed, and causing the light spot generated by the third pulse laser on the surface to be processed to move relative to the surface to be processed in a specified manner, so as to process the surface to be processed.

[0017] According to the second aspect of the present application, a laser processing method is proposed, comprising: injecting a linearly polarized first pulse laser with a specified polarization direction into a spatial light modulator; loading a specified phase map on the spatial light modulator; according to the phase map, adjusting the polarization direction of the first pulse laser pixel by pixel in the spatial light modulator, so that the linear polarization direction of the first pulse laser passing through the gray area of ​​the phase map and the linear polarization direction of the first pulse laser passing through the white area of ​​the phase map are perpendicular to each other, thereby obtaining a second pulse laser; according to the phase map, polarization filtering the second pulse laser, and shaping the second pulse laser into a third pulse laser with a specified pattern of light spot; focusing the third pulse laser onto the surface to be processed, and causing the light spot generated by the third pulse laser on the surface to be processed to move relative to the surface to be processed in a specified manner, so as to process the surface to be processed.

[0018] It can be understood that the beneficial effects of the above-mentioned second aspect compared with the related art are the same as the beneficial effects of the above-mentioned first aspect compared with the related art. Please refer to the relevant description in the above-mentioned first aspect and will not be repeated here.

[0019] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of an implementation of a laser processing device according to an embodiment of the present application.

[0021] Figure 2 It is a schematic diagram of another implementation of the laser processing device of an embodiment of the present application.

[0022] Figure 3 It is a flow chart of the laser processing method of an embodiment of the present application.

[0023] Figure 4 It is a schematic diagram of the optical path of an implementation method of the laser processing device of an embodiment of the present application.

[0024] Figure 5 yes Figure 4 Schematic diagram of the 4f beam reduction system of the laser processing device.

[0025] Figure 6 It is a combination Figure 4 Schematic diagram of the polarization change of the laser pulse in the optical path in Example 1.

[0026] Figure 7 yes Figure 6 An enlarged view of point B of the embodiment.

[0027] Figure 8 yes Figure 6 An enlarged view of section C of the embodiment.

[0028] Fig. 9 yes Figure 6 An enlarged view of D of the embodiment

[0029] Fig.10 yes Figure 6 An enlarged view of the embodiment at E

[0030] Fig.11 It is a schematic diagram of the positive mold result of the laser ablation of the five-pointed star in Example 1.

[0031] Fig.12 It is a schematic diagram of the reverse mold result of the laser ablation five-pointed star in Example 1.

[0032] Fig.13 It is a schematic diagram of the positive mode phase diagram of the laser ablated five-pointed star in Example 1.

[0033] Fig.14 Schematic diagram of the inverse phase diagram of the laser ablated five-pointed star in Example 1.

[0034] Fig.15 It is a schematic diagram of the positive mold result of the single exposure processing of Example 2 containing multiple structures of the antenna combination.

[0035] Fig.16 It is a schematic diagram of the reverse mold result of the antenna combination containing multiple structures processed by single exposure in Example 2.

[0036] Fig.17 It is a schematic diagram of the positive mode phase diagram of the antenna combination containing multiple structures in the single exposure processing of Example 2.

[0037] Fig.18 It is a schematic diagram of the reverse mode phase diagram of the antenna combination containing multiple structures in the single exposure processing of Example 2.

[0038] Fig.19 This is a schematic diagram of the results of laser single pulse ablation of a one-dimensional nanograting in Example 3.

[0039] Fig. 20 yes Fig.19 A local enlarged view of point F in the schematic diagram of the results of single-pulse laser ablation of one-dimensional nanogratings.

[0040] Fig.21 This is a schematic diagram of the results of laser single pulse processing by controlling the hexagonal arrangement of concentric ring arrays through scanning speed.

[0041] Fig. 22 This is a schematic diagram of the results of laser single pulse processing by controlling the diamond arrangement of concentric ring arrays through scanning speed.

[0042] Fig.23 This is a schematic diagram of the results of laser single pulse processing by controlling the square arrangement of concentric ring arrays through scanning speed.

[0043] Figure numerals: 100: laser input module, 200: laser shaping module, 300: polarization filtering module, 401: processing module, 10: surface to be processed, 500: controller, 110: laser light source assembly, 120: energy adjustment assembly, 130: laser beam expansion assembly, 140: laser output assembly, 210: polarization adjustment assembly, 220: spatial light modulator, 310: polarization filtering assembly, 320: polarization selection assembly, 410: focusing assembly, 420: displacement assembly, 111: laser, 121: electric half-wave plate, 122: Glenn assembly Mirror, 122a: block, 131: first concave lens, 141: first convex lens, 211: first half-wave plate, 221: first reflector, 222: spatial light modulator, 223: second reflector, 311: first quarter-wave plate, 312: polarizer, 321: polarization selective wave plate, 411: second convex lens, 412: first dichroic mirror, 501: second dichroic mirror, 503: third reflector, 504: CMOS camera, 502: LED light source, 413: objective lens, 421: three-axis precision translation stage, 501: processing control system. DETAILED DESCRIPTION

[0044] In the following description, specific details such as specific system structures, technologies, etc. are proposed for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the embodiments of the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, optical paths, and methods are omitted to prevent unnecessary details from hindering the description of the embodiments of the present application.

[0045] It should be noted that although a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0046] For the sake of convenience and simplicity in expression, some basic optical path adjustment devices, such as concave lenses, convex lenses, and reflectors, are omitted in the present embodiment. These optical path adjustment devices can actually be set at various locations in the optical path of the embodiment of the present application, and their setting method does not affect the realization of the beneficial effects of the embodiment of the present application.

[0047] A spatial light modulator is a light modulation device composed of multiple independent units, arranged in one or two dimensions in space. Each unit can independently receive control of an optical signal or an electrical signal, and change its own optical properties according to the signal, thereby modulating the light wave illuminated on it. For example, the amplitude or intensity, phase, polarization state and wavelength of the light distribution in space can be changed under the control of an electrical drive signal or other signal. In particular, the working principle of a liquid crystal spatial light modulator is to independently control each pixel by changing the addressing voltage. Different voltages will cause the liquid crystal molecules to produce a corresponding deflection angle to produce a specific phase delay.

[0048] The phase map is a grayscale image that can be applied to the liquid crystal spatial light modulator. The grayscale value is variable from 0 to 255. The grayscale value corresponds to the driving voltage applied to the pixel unit of the liquid crystal spatial light modulator. By changing the grayscale value of the image, the voltage can be controlled, thereby achieving phase regulation.

[0049] according to Figure 1 The laser processing device provided in the embodiment of the present application is described.

[0050] Reference Figure 1 The laser processing device may include a laser input module 100 for providing a first pulse laser to a laser shaping module 200 described later.

[0051] specifically refer to Figure 2The laser input module 100 can be composed of a laser light source assembly 110 and a laser output assembly 140. The laser light source assembly 110 can be a laser capable of generating pulsed lasers, such as a fiber laser, a Q-switched laser, etc., or a system capable of outputting pulsed lasers, such as a chirped laser system composed of a seed source, a stretcher, an amplifier, and a compressor. In order to meet the needs of subsequent processing, the laser light source assembly 110 should be able to output pulsed lasers with a pulse width of femtoseconds or picoseconds. The energy distribution of the laser can be a Gaussian distribution or a flat-top distribution. The laser output assembly 140 is used to adjust and collimate the optical path of the original laser emitted by the laser light source assembly 110 and output it as the first pulsed laser to the laser shaping module 200.

[0052] In some embodiments, reference Figure 2 The laser input module 100 also has an energy adjustment component 120, which is used to adjust the energy of the original laser emitted by the laser light source component 110. The energy adjustment component 120 is controlled by the controller 500. The energy adjustment component 120 can be controlled by the controller 500 to adjust the energy of the first pulse laser output by the laser input module 100.

[0053] In some embodiments, reference Figure 2 The laser input module 100 also has a laser beam expansion component 130, which is used to amplify the beam width of the original laser beam emitted by the laser light source component 110 and cooperate with the laser output component 140 described later to output the first pulse laser.

[0054] Reference Figure 1 The laser processing device has a laser shaping module 200, which is used to obtain a first pulse laser and polarize-modulate the first pulse laser according to a preset phase diagram so that the linear polarization directions of the first pulse laser passing through the gray area of ​​the phase diagram and the linear polarization directions of the first pulse laser passing through the white area of ​​the phase diagram are perpendicular to each other, thereby obtaining a second pulse laser.

[0055] specifically refer to Figure 2 The laser shaping module 200 includes a polarization adjustment component 210 and a spatial light modulator 220. After acquiring the first pulse laser, the first pulse laser is incident on the polarization adjustment component 210 and modulated into a linear polarized light with a specified polarization direction in the polarization adjustment component 210. Then, the linear polarized light is output to the spatial light modulator 220. The spatial light modulator 220 performs polarization modulation on the linear polarized light pixel by pixel according to the phase diagram preset in the controller 500, so that in the spatial light modulator 220, as shown in FIG. Figure 4 The linear polarization directions of the linear polarized light passing through the gray area of ​​the phase diagram and the white area of ​​the phase diagram are perpendicular to each other. For example, Figure 6It is a schematic diagram of the polarization change of a laser pulse in an optical path of an embodiment of the present application. In this embodiment, after being modulated by a spatial light modulator 222 loaded with a five-pointed star phase diagram, the polarization direction of the linearly polarized light inside the five-pointed star corresponding to the white part of the phase diagram is perpendicular to the polarization direction outside the five-pointed star corresponding to the gray part of the phase diagram.

[0056] In some embodiments, the phase map is a binary phase map with a grayscale gradient at the boundary. Specifically, the binary phase map is an eight-bit phase map with a grayscale gradient transition by adding a grayscale gradient at the grayscale boundary between white and gray. The polarization, phase, and amplitude of the light spot are regulated pixel by pixel by loading the phase map to the spatial light modulator 220. When the linearly polarized light with a specified polarization direction passes through the grayscale gradient portion of the phase map in the spatial light modulator 220, the polarization direction is elliptical polarization. Specifically, refer to Figure 6 and Figure 7 , Figure 7 yes Figure 6 The enlarged schematic diagram of A in Figure 6 In the embodiment of the present invention, the spatial light modulator 222 is loaded with the phase diagram specified in the embodiment, and the polarized light modulated by the spatial light modulator is merged into the main light path through the second reflector 223, and the polarization direction of the polarized light passing through the white part of the phase diagram and the polarization direction of the gray part are perpendicular to each other. Figure 7 When passing through the grayscale gradient part of the above phase diagram, since the change of the electric vector is gradual, the polarized light will present an elliptical polarization with a gradual ellipticity between the two polarization directions perpendicular to each other. After other modulations described later, the edge of the light spot formed on the surface to be processed described later has a gradual energy distribution, which can form a finer pattern with a shape closer to the original one in the processing scale.

[0057] Reference Figure 1 The laser processing device also has a polarization filtering module 300, which is used to perform polarization filtering on the second pulse laser to obtain a third pulse laser with a light spot of a specified pattern, so as to process the surface 10 to be processed by the third pulse laser.

[0058] Specifically, refer to Figure 4 The polarization filter module 300 may be composed of a quarter wave plate and a polarizer, and by adjusting the angle between the quarter wave plate and the polarizer, the second laser pulse may be polarized and filtered, and the light spot may be shaped into a desired pattern, thereby obtaining a third pulse laser.

[0059] Further, refer to Figure 6 , Figure 8 and Fig. 9 , Figure 8 yes Figure 6 The enlarged schematic diagram of point B, Fig. 9 yes Figure 6 The enlarged schematic diagram of C. Figure 6 In the embodiment, Figure 1 The polarization filter module 300 includes a first quarter wave plate 311 and a polarizer 312. The second pulse laser modulated by the spatial light modulator 222 enters the first quarter wave plate 311 through the second reflector 223. Figure 8 , after being modulated by the first quarter wave plate 311, the elliptic polarization with gradually changing ellipticity is converted into linear polarization with gradually changing polarization direction. Fig. 9 , through the filtering of the polarizing plate 312, the edge of the light spot formed on the surface to be processed described later has a gradual energy distribution.

[0060] In some embodiments, the polarization filtering module 300 further includes a polarization selection component 320. The polarization selection component 320 modulates the polarization of the third pulse laser according to the processing requirements of the surface to be processed, and modulates the third pulse laser into linearly polarized light or circularly polarized light.

[0061] Specifically, refer to Figure 6 and Fig.10 , Fig.10 yes Figure 6 An enlarged schematic diagram of point E. Figure 6 In the embodiment of the present invention, the polarization selection component is a polarization selection wave plate 321. In this embodiment, a quarter wave plate is selected, so reference is made to Fig.10 , the third pulse laser can be modulated into circularly polarized light.

[0062] It should be noted that in laser processing, linear polarized light will produce a stronger ablation effect in the direction perpendicular to the linear polarization, and can make the line width of the processed structure in the direction perpendicular to the polarization thinner, while the various aspects of circular polarized light are uniform. In laser processing, the processing intensity in each direction is the same, which can make the resulting structure more uniform. Therefore, the composition of the polarization selection component 320 can be selected according to specific processing needs. For example, when the processing structure is not directional, a quarter wave plate is selected, and when it is directional, a half wave plate is selected.

[0063] Reference Figure 2 The laser processing device also has a processing module 400, which is used to process the surface 10 to be processed using the third pulse laser. The processing module 400 includes a displacement component 420 and a focusing component 410; the focusing component 410 is used to shrink the third pulse laser and focus it on the surface 10 to be processed according to the processing requirements. The displacement module is used to make the processing spot generated by the third pulse laser on the surface 10 to be processed move with the surface 10 to be processed in a predetermined moving manner.

[0064] Based on the above description, Figure 1 and Figure 2The implementation method can use the spot generated by the third laser pulse to process the surface 10 to be processed in one step. Since the spot has formed the pattern to be processed in advance, the pattern can be directly processed onto the surface 10 to be processed. Therefore, the workpiece is subjected to single-pulse material removal or modification by using the ultrafast laser pulse after pattern shaping, thereby realizing efficient, large-area, and low-cost preparation of micro-nano structure arrays on the surface 10 to be processed.

[0065] Further integration Figure 2 The implementation method is to fine-tune the polarization and edge energy distribution of the shaped light spot to achieve more precise processing of micro-nano patterns, achieve smaller pattern feature sizes, and realize high-precision design of micro-nano structures.

[0066] Combined with the above laser processing method, according to Figure 3 The embodiment of the present application further proposes a laser processing method, including: According to the second aspect of the present application, a laser processing method is proposed, including:

[0067] S100: injecting a linearly polarized first pulse laser with a predetermined polarization direction into the spatial light modulator 220;

[0068] S200: loading a prescribed phase map onto the spatial light modulator;

[0069] S300: According to the phase map, the polarization direction of the first pulse laser is adjusted pixel by pixel in the spatial light modulator, so that the linear polarization direction of the first pulse laser passing through the gray area of ​​the phase map and the linear polarization direction of the first pulse laser passing through the white area of ​​the phase map are perpendicular to each other, thereby obtaining a second pulse laser;

[0070] S400: performing polarization filtering on the second pulse laser to shape the second pulse laser into a third pulse laser having a light spot of a specified pattern;

[0071] S500: focusing the third pulse laser onto the surface to be processed, and making the light spot generated by the third pulse laser on the surface to be processed move relative to the surface to be processed in a prescribed manner, so as to process the surface to be processed.

[0072] It can be understood that the above method corresponds to the laser processing device of the embodiment of the present application, has similar technical features and the same beneficial effects, and will not be repeated here.

[0073] Combine the following Figure 4 , and describes specific examples of this implementation.

[0074] Figure 4It is an optical path diagram of a specific embodiment of the embodiment of the present application. The laser 111 emits an ultrafast pulse laser. In some embodiments, the ultrafast laser is a Gaussian linear polarized light with a central wavelength of 520nm and a pulse width of 300fs. The ultrafast pulse laser passes through an energy adjustment component 120 composed of an electric half-wave plate 121 and a Glan prism 122 to adjust the laser energy. The processing control system can control the electric half-wave plate 121 to achieve control of the laser energy. And further, the laser is collimated and expanded by the first concave lens 131 and the first convex lens 141, and output to the first half-wave plate 211 for polarization adjustment, to generate a linearly polarized Gaussian beam with a specified polarization direction, and then the linearly polarized Gaussian beam is irradiated to the spatial light modulator 222 through the first reflector 221. By loading a binary phase diagram with a gradient boundary grayscale on the spatial light modulator 222, the incident light can be polarized pixel by pixel, and the phase diagram can be controlled by the processing control system. The outgoing light passes through the second reflector 223 and enters the main optical path again. The light beam entering the main optical path then passes through the polarization filter assembly 310 composed of the first quarter wave plate 311 and the polarizer 312 in turn, and the light spot with energy Gaussian distribution is shaped into the designed pattern. Furthermore, a polarization selection wave plate 321 is also provided in this embodiment, and the polarization selection wave plate 321 can adjust the polarization of the shaped light spot according to the processing requirements. The laser pulse that has completed the polarization selection passes through the first dichroic mirror 501, and is focused to the processing surface through the 4f beam reduction system composed of the second convex lens 411 and the objective lens 413. Through the linkage of the three-axis precision translation stage 421 and the above-mentioned laser 111, patterned shaping femtosecond laser scanning processing of specific processing parameters can be realized.

[0075] Figure 5 yes Figure 4 Schematic diagram of the 4f beam reduction system. Figure 4 The 4f beam reduction system is composed of a spatial light modulator 222, a second convex lens 411, an objective lens 413, and a surface to be processed 10. By adjusting the distance from the spatial light modulator 222 to the surface to be processed 10 to twice the focal length of the second convex lens 411 plus twice the focal length of the objective lens 413, the focus position of the light spot can be adjusted to the surface to be processed 10, and the shape of the patterned light spot after focusing can be kept intact.

[0076] on the other hand, Figure 4 In the embodiment, an LED light source 502 is provided, which emits monochromatic light and is reflected by the second dichroic mirror 501, and is focused to the surface 10 to be processed through the first dichroic mirror 412 and the objective lens 413 in sequence, and then propagates along the incident path, passes through the focusing objective lens 413, the first dichroic mirror 412 and the second dichroic mirror 501 in sequence, and finally enters the CMOS camera 504 through the third reflecting mirror for imaging, thereby realizing real-time observation of the laser processing status of the surface 10 to be processed.

[0077] According to the above Figure 4 and Figure 5 The laser processing system of the specific embodiment, due to the linkage between the laser and the three-axis precision translation stage 421, enables the relative movement of the processing sample and the laser pulse, thereby realizing the selective ablation or modification of the material surface by a single pulse, that is, the separate direct writing of a single pulse, thereby achieving the purpose of efficient one-step processing of surface sub-wavelength micro-nano structures.

[0078] Although in the above-mentioned embodiment, it is mentioned that the polarization selection component 320 is provided in the laser processing device, it is not limited to this. Those skilled in the art should know that although the polarization selection component 320 increases the processing accuracy, the laser processing device of the embodiment of the present application can still achieve the effect of improving the processing efficiency of a single patterning process even if the polarization selection component 320 is not provided.

[0079] Although in the above embodiment, it is mentioned that the energy distribution of the first pulse laser is Gaussian distribution, it is not limited to this. It can be understood that even if the first pulse laser is not Gaussian distribution, although it will reduce the processing accuracy of the laser, it can still have the effect of improving the processing efficiency of one-time patterning compared with other processing schemes. And when the energy distribution of the first pulse laser is flat-top distribution, the energy will be more uniform, so a flat-top light modulation element, such as a two-dimensional optical element or a chopper, can be added to the optical path to obtain a flat-top beam, so that the energy used for processing is more uniform.

[0080] Although in the above embodiment, it is mentioned that the laser processing device may have a laser input module 100, it is not limited thereto. It should be noted that the laser input module 100 is only provided for the convenience of description in the embodiment, and it is not limited to the laser input module 100 being provided inside the laser processing device. The laser processing device of the embodiment of the present application may also use external laser pulses to achieve processing. For example, a femtosecond laser may be provided outside the laser processing device, and the laser outputs femtosecond laser and injects it into the laser shaping module 200, which may also achieve the technical effects of the embodiment of the present application.

[0081] Although in the above embodiment, it is mentioned that the energy regulation component 120 is composed of a Glan lens and an electric half-wave plate, it is not limited to this. For example, the energy regulation of the first pulse laser can also be completed by a combination of polarizing plates or a polarization beam splitter. It should be understood that as long as the energy regulation component 120 can complete the adjustable modulation of the laser pulse energy, it will be sufficient.

[0082] Although in the above embodiment, the liquid crystal spatial light modulator 220 is used for laser shaping, it is not limited thereto. For example, a DMD (digital micromirror device) can also be used to achieve laser shaping, so the laser shaping module 200 can also use a DMD. It should be understood that it only needs to be able to load a phase map and complete laser shaping by modulating the polarization of the laser.

[0083] Combine the following Figure 4 The specific embodiments are described below.

[0084] [Example 1]

[0085] Combination Figure 4 A method for preparing a five-pointed star positive and negative mold array structure comprises the following steps:

[0086] Step 1: Determine the parameters required for laser processing based on processing requirements.

[0087] Specifically Fig.11 This is a schematic diagram of the five-pointed star positive mode structure. The size of the five-pointed star positive mode structure is 10μm and the period is 10μm. Fig.12 It is a schematic diagram of a five-pointed star inverse mold structure. The outer frame of the five-pointed star inverse mold structure is a square with a side length of 10μm, the internal five-pointed star hollow size is 9μm, and the period is 10μm.

[0088] Therefore, the array area for preparing the five-pointed star positive and negative mold structures can be set to 10mm×10mm.

[0089] Step 2: According to the processing size, consider selecting a 50x objective lens 413 (NA = 0.55) to focus the laser pulse. Figure 5 The parameters of the 4f shrinkage system are selected as f1=1000mm and f2=4mm.

[0090] Step 3: Design the phase diagram required for five-pointed star spot shaping.

[0091] Specifically, in this embodiment, the single pixel size of the spatial light modulator 222 is 12.5 μm, and the number of pixels of the width of the five-pointed star positive mold calculated by the 4f scaling ratio is 200. The number of pixels of the side length of the five-pointed star reverse mold outer frame is 200, and the number of pixels of the internal five-pointed star width is 180. The grayscale value of the part of the light spot energy that needs to be retained in the phase image is 215 (that is, the white part in the phase image), such as the five-pointed star positive mold pattern and the five-pointed star reverse mold outer frame. The grayscale value of the part of the light spot that needs to be filtered is 85 (that is, the gray part in the phase image), such as the hollow part inside the five-pointed star reverse mold. See Fig.13 and Fig.14 Schematic diagram of the phase image, adding grayscale gradient at the grayscale mutation point of the phase image, and the gradient curve satisfies a specific function.

[0092] Step 4: Set the angle of each wave plate in the processing light path.

[0093] Specifically, Figure 6 The figure is a schematic diagram of the five-pointed star positive mode laser pattern shaping process in this embodiment, wherein the angle between the fast axis direction of the electric half-wave plate 121 and the horizontal direction is adjusted to -22.5°, the initial horizontal linear polarized laser passes through the polarization direction of -45°, and after being reflected by the spatial light modulator 222 loaded with the designed phase diagram, the polarization of the light spot through the gray and white areas of the phase diagram is mutually perpendicular linear polarization, and the middle is an elliptical polarization transition with a gradual elliptical angle. The fast axis direction of the first quarter wave plate 311 is adjusted to an angle of 45° with the horizontal direction, at which time the polarization of the light spot through the gray and white areas of the phase diagram is mutually perpendicular, and the middle is a linear polarization transition with a gradual polarization direction. The horizontal axis of the selected polarizer 312 is at an angle of 45° with the horizontal direction, at which time the light spot of the pattern passing through the white part of the phase diagram is retained, and the gray part is filtered. Because the processing pattern is not directional, the polarization selection wave plate 321 can be selected as a quarter wave plate, and the angle between the fast axis direction and the horizontal direction is 45°, and the polarization of the shaping laser used for the final processing is circular polarization.

[0094] Step 5: Select the surface 10 to be processed, the sample is quartz glass on which 2nm of chromium and 10nm of gold are sequentially evaporated. Use acetone and anhydrous alcohol to ultrasonically clean the surface 10 for 15 minutes respectively, and then blow dry with nitrogen in a dust-free environment to obtain a clean surface 10 to be processed.

[0095] Step 6: Fix the surface 10 to be processed on the stage of the three-axis precision translation stage 421 and adjust the translation stage to make it horizontal. By adjusting the stage of the three-axis precision translation stage 421, the sample to be processed is at the focus of the laser.

[0096] Step 7: Set the laser pulse width to 300fs, the wavelength to 520nm, the repetition rate to 10kHz, the laser single pulse energy to 0.5μJ, and the writing speeds to 100mm / s and 97mm / s respectively through the control system. In this embodiment, the selection of single pulse lithography processing parameters is not limited to the repetition frequency and scanning speed used in the example of the present invention. Proportionally increasing or decreasing the repetition frequency and scanning speed can achieve the same arrangement of array structures. It should be noted that a slight change in the writing speed can change the arrangement of the array, which will be explained in Example 4 described later.

[0097] Step 8: During the processing, the processing control system controls the stage of the three-axis precision translation stage 421 to move 10 mm in the horizontal direction along the X-axis to obtain the first row of five-pointed star positive and negative mold array structures.

[0098] Step 9: Control the stage back to the initial position and move a certain distance along the Y axis to start the second row of processing.

[0099] Step 10: Repeat steps 8 and 9 to achieve large-area preparation of micro-nano structures.

[0100] The effect of this embodiment is as follows Fig.11 and Fig.12 As shown, the processing of the positive and negative mold structure arrays of the five-pointed star was achieved, and the period was 10μm.

[0101] [Example 2]

[0102] Combination Figure 4 , an embodiment of a processing method for realizing one-time exposure of multiple micro-nano structures in a pattern unit by a patterned single-pulse lithography method is described, and the embodiment includes the following steps:

[0103] Step 1: According to the processing requirements, see Fig.17 , Fig.18 Phase diagram, each processing unit contains five antenna structures, such as a single antenna structure line width of 1μm, the overall antenna combination structure length of 18μm, width of 4μm, period of 4.8μm; antenna structure reverse mold line width of 1μm, reverse mold frame length of 20μm, width of 4.8μm, period of 4.8μm. Prepare the antenna combination structure positive and negative mold structure array area of ​​10mm×10mm.

[0104] Step 2: According to the processing size, consider selecting a 50x objective lens 413 (NA = 0.55) to focus the laser pulse, so Figure 5 The parameters of the 4f shrinkage system are selected as f1=1000mm and f2=4mm.

[0105] Step 3: Design the phase diagram required for light spot shaping of the antenna combination structure.

[0106] Specifically, see Fig.17 and Fig.18 The single pixel size of the spatial light modulator 222 used is 12.5μm. The number of pixels of the antenna line width calculated by the 4f scaling ratio is 20, and the number of pixels of the width of the antenna combination structure reverse mold outer frame is 400 and 96 pixels. The grayscale value of the part of the phase image that needs to retain the spot energy is 215 (white part), such as the antenna structure positive mold pattern and the outer frame of the structure combination reverse mold. The grayscale value of the part of the spot that needs to be filtered is 85 (gray part), such as the hollow part inside the antenna structure reverse mold. A grayscale gradient is added at the grayscale mutation of the phase image, and the gradient curve satisfies a specific function.

[0107] Step 4: Set the angle of each wave plate in the processing light path.

[0108] Specifically, the angle between the fast axis direction of the electric half-wave plate 121 and the horizontal direction is adjusted to -22.5°, and the angle between the fast axis direction of the first quarter-wave plate 311 and the horizontal direction is 45°, and the angle between the horizontal axis of the polarizer 312 and the horizontal direction is 45°. Because the processing pattern has no directionality, the polarization selective wave plate 321 can be a quarter-wave plate, and the angle between its fast axis direction and the horizontal direction is 45°. Therefore, the polarization of the shaped laser used for the final processing is circular polarization.

[0109] Step 5: Select the surface 10 to be processed, the sample is quartz glass on which 2nm of chromium and 10nm of gold are sequentially evaporated. Use acetone and anhydrous alcohol to ultrasonically clean the surface 10 for 15 minutes respectively, and then blow dry with nitrogen in a dust-free environment to obtain a clean surface 10 to be processed.

[0110] Step 6: Fix the sample to be processed on the stage of the three-axis precision translation stage 421 and adjust the translation stage to make it horizontal, and adjust the stage of the three-axis precision translation stage 421 so that the surface 10 to be processed is at the focus of the laser.

[0111] Step 7: Through the processing control system, set the laser pulse width to 300fs, the wavelength to 520nm, the repetition rate to 10kHz, the laser single pulse energy to 0.7μJ, and the writing speed to 48mm / s.

[0112] Step 8: During the processing, the control system controls the three-axis precision translation stage 421 to move 10 mm along the X-axis in the horizontal direction to obtain the first row of antenna-type combined structures.

[0113] Step 9: Control the stage back to the initial position and move a certain distance along the Y axis to start the second row of processing.

[0114] Step 10: Repeat steps 8 and 9 to achieve large-area preparation of micro-nano structures.

[0115] The effect of this embodiment is as follows Fig.15 and Fig.16 As shown, the positive and negative mold structure arrays of the antenna combination are processed separately, and an antenna unit processed once contains five structures, and the period is 4.8μm.

[0116] [Example 3]

[0117] Combination Figure 4 A method for processing a one-dimensional nano-grating by patterned single-pulse lithography in this embodiment is described, and includes the following steps:

[0118] Step 1: According to the processing requirements, the period of the one-dimensional nano-grating is 510nm, the line width is 60nm, the groove shape is rectangular, and the length is 5μm.

[0119] Step 2: According to the processing size, consider selecting a 100x objective lens 413 (NA = 0.8) to focus the laser pulse. Figure 5 The parameters of the 4f shrink beam system shown in FIG. 1 are selected as f1=1000 mm and f2=2 mm.

[0120] Step 3: Design the phase diagram required for rectangular spot shaping.

[0121] Specifically, the single pixel size of the spatial light modulator 222 used is 12.5 μm, and the width of the phase image rectangle calculated by the 4f scaling ratio is 20 pixels and the length is 200 pixels. The grayscale value of the part of the phase image that needs to retain the spot energy is 215 (white part), such as the rectangle in the embodiment of the present application. The grayscale value of the part of the spot that needs to be filtered is 85 (gray part), such as the part other than the rectangle in this case. And add a grayscale gradient at the grayscale mutation of the phase image, and the gradient curve satisfies a specific function;

[0122] Step 4: Set the angle of each wave plate in the processing light path.

[0123] Specifically, the angle between the fast axis direction of the electric half-wave plate 121 and the horizontal direction is adjusted to -22.5°, the angle between the fast axis direction of the first quarter-wave plate 311 and the horizontal direction is adjusted to 45°, and the angle between the horizontal axis of the polarizer 312 and the horizontal direction is 45°. Since the processing pattern has obvious directionality, the polarization selection wave plate 321 can be selected as a half-wave plate, and the angle between its fast axis direction and the horizontal direction is 22.5°. The polarization of the shaped laser used for the final processing is a linear polarization parallel to the long axis direction of the rectangle.

[0124] Step 5: Select a sample of the surface 10 to be processed, which is a quartz glass on which 2 nm of chromium and 10 nm of gold are sequentially evaporated. The surface 10 to be processed is ultrasonically cleaned with acetone and anhydrous alcohol for 15 min respectively, and then dried with nitrogen in a dust-free environment to obtain a clean surface 10 to be processed.

[0125] Step 6: Fix the surface 10 to be processed on the stage of the three-axis precision translation stage 421 and adjust the translation stage to make it horizontal, and adjust the stage of the three-axis precision translation stage 421 to make the surface 10 to be processed be at the focus of the laser.

[0126] Step 7: Through the processing control system, set the laser pulse width to 300fs, the wavelength to 520nm, the repetition rate to 10kHz, the laser single pulse energy to 0.4μJ, and the writing speed to 5.1mm / s.

[0127] Step 8: During the processing, the three-axis precision translation stage 421 is controlled by the processing control system to move 5 mm in the horizontal direction along the X-axis to obtain a single-row one-dimensional nano-grating structure.

[0128] The processing effect of this embodiment can be seen in Fig.19 , Fig. 20 The period of the processed one-dimensional grating is 509nm and the line width is 62nm.

[0129] [Example 4]

[0130] Combination Figure 4 The present invention also relates to a method for controlling the arrangement of a patterned array by adjusting the scanning speed. In this embodiment, a method for preparing a concentric ring array structure by patterned single pulse lithography is provided, comprising the following steps:

[0131] Step 1: According to the processing requirements, the outer diameter of the processed concentric ring is 4μm, the inner diameter is 3μm, the outer diameter of the inner ring is 2μm, and the inner diameter is 1μm. It is necessary to process the concentric ring arrays arranged in hexagons, diamonds, and squares respectively, and the prepared structural array area is 10mm×10mm.

[0132] Step 2: According to the processing size, consider selecting a 100x objective lens 413 (NA = 0.8) to focus the laser pulse. Figure 5 The parameters of the 4f shrinkage system shown in FIG. 1 are selected as f1=1000 mm and f2=2 mm.

[0133] Step 3: Design the phase diagram required for concentric ring structure spot shaping.

[0134] Specifically, the single pixel size of the spatial light modulator 222 used is 12.5 μm, and the outer diameter pixel number of the concentric ring binary phase image calculated by the 4f scaling ratio is 160, the inner diameter pixel number is 120, the outer diameter pixel number of the inner ring is 80, and the inner diameter pixel number is 40. The gray value of the part of the spot energy that needs to be retained in the inner and outer rings of the phase image is positioned at 215 (white), the gray value of the part of the spot that needs to be filtered is 85 (gray), and a gray gradient is added at the grayscale mutation of the phase image, and the gradient curve satisfies a specific function.

[0135] Step 4: Set the angle of each wave plate in the processing optical path, select the angle between the electric fast axis and the horizontal direction to be -22.5°, the angle between the fast axis of the first quarter wave plate 311 and the horizontal direction to be 45°, and the angle between the horizontal axis of the polarizer 312 and the horizontal direction to be 45°. Because the processing pattern is not directional, the polarization selection wave plate 321 is selected as a quarter wave plate, and the angle between the fast axis and the horizontal direction is 45°. The final shaping laser polarization used in the processing is circular polarization.

[0136] Step 5: Select the sample to be processed, which is a quartz glass on which 2nm of chromium and 10nm of gold are sequentially evaporated. The sample to be processed is ultrasonically cleaned with acetone and anhydrous alcohol for 15 minutes respectively, and then dried with nitrogen in a dust-free environment to obtain a clean sample to be processed.

[0137] Step 6: Fix the sample to be processed on the stage of the three-axis precision translation stage 421 and adjust the translation stage to make it horizontal, and adjust the stage of the three-axis precision translation stage 421 so that the sample to be processed is at the laser focus.

[0138] Step 7: Through the control system, set the laser pulse width to 300fs, the wavelength to 520nm, the repetition rate to 10kHz, the laser single pulse energy to 0.2μJ, and the speeds for writing hexagonal, diamond, and square arrays to 47.5mm / s, 47mm / s, and 46.5mm / s respectively.

[0139] Step 8: During the processing, the control system controls the three-axis precision translation stage 421 to move 10 mm along the X-axis in the horizontal direction to obtain the first row of concentric ring structures.

[0140] Step 9: Control the stage back to the initial position and move a certain distance along the Y axis to start the next line of processing.

[0141] Step 10: Repeat steps 8 and 9 multiple times to achieve large-area preparation of micro-nano structures.

[0142] The effect of this embodiment is as follows Fig.21 , Fig. 22 ,and Fig.23 As shown, the arrangement of the pattern array is changed by changing the scanning speed without affecting the duty cycle. Fig.21 The scanning speed is 47.5 mm / s. Fig. 22 The scanning speed is 47mm / s. Fig.23 The scanning speed in the image is 46.5 mm / s, and concentric ring arrays with hexagonal, diamond and square distributions are obtained respectively.

[0143] Therefore, according to the description of the above embodiments, it is not difficult to understand that the micro-nano structure prepared by the laser processing method or laser processing equipment of the embodiment of the present application can adjust its shape, period and duty cycle according to actual needs. And by using the gradual binary phase image laser shaping method compared with the traditional phase image laser shaping method, the energy is more uniform and can achieve a processing accuracy of hundreds of nanometers.

[0144] It should also be understood that the reference to "one embodiment" or "some embodiments" described in the specification of the embodiments of the present application means that one or more embodiments of the embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the sentences "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. In the description of the embodiments of the present application, unless otherwise clearly defined, the words such as setting, installing, connecting, etc. should be understood in a broad sense, and the technicians in the relevant technical field can reasonably determine the specific meanings of the above words in the embodiments of the present application in combination with the specific content of the technical solution.

[0145] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. Laser processing equipment, It is characterized in that The device comprises: a laser shaping module, used to obtain a first pulse laser, and polarization modulate the first pulse laser according to a preset phase diagram, so that the linear polarization directions of the first pulse laser passing through the gray area of ​​the phase diagram and the part passing through the white area of ​​the phase diagram are perpendicular to each other, thereby obtaining a second pulse laser; The polarization filtering module is used to perform polarization filtering on the second pulse laser to obtain a third pulse laser with a light spot of a specified pattern, so as to process the surface to be processed by the third pulse laser.

2. The laser processing device according to claim 1, It is characterized in that The laser processing device also includes: A laser input module, the laser input module is used to generate the first pulse laser and output the first pulse laser to the laser shaping module; The first pulse laser is a picosecond pulse laser or a femtosecond pulse laser, and the energy distribution of the light spot generated by the first pulse laser satisfies a Gaussian distribution or a flat-top distribution.

3. The laser processing device according to claim 2, It is characterized in that The laser input module comprises: A laser light source assembly, wherein the laser light source assembly is used to generate original pulse laser, A laser output component, the laser output component is used to collimate and output the first pulse laser; The laser input module further includes at least one of the following: An energy regulating component, the energy regulating component is used to regulate the energy of the original pulse laser; A laser beam expansion component is used to expand the original pulse laser.

4. The laser processing device according to claim 1, It is characterized in that The laser shaping module includes: a polarization adjustment component and a spatial light modulator: The polarization adjustment component is used to modulate the first pulse laser into linear polarized light with a specified polarization direction, and output the linear polarized light to the spatial light modulator; The spatial light modulator is used to perform polarization modulation on the linear polarized light pixel by pixel according to the phase diagram, so that the linear polarization directions of the portion of the linear polarized light passing through the gray area of ​​the phase diagram and the portion of the linear polarized light passing through the white area of ​​the phase diagram are perpendicular to each other.

5. The laser processing device according to any one of claims 1 to 4, It is characterized in that The phase image is a phase image of edge grayscale gradient, and a gradient curve corresponding to the edge grayscale gradient satisfies a specified function.

6. The laser processing device according to claim 5, It is characterized in that The polarization filtering module includes a quarter wave plate and a polarizer, and is used to adjust the quarter wave plate and the polarizer according to the polarization angle of the second pulse laser to perform polarization filtering on the second pulse laser to obtain the third pulse laser with a light spot of a specified pattern.

7. The laser processing device according to claim 1, 2, 3, 4 or 6, It is characterized in that The polarization filtering module includes a polarization selection component, and the polarization selection component modulates the polarization of the third pulse laser according to the processing requirements of the surface to be processed, and modulates the third pulse laser into linear polarized light or circular polarized light.

8. The laser processing device according to claim 7, It is characterized in that The laser processing device further comprises a processing module for processing the surface to be processed using the third pulse laser, wherein the processing module comprises a displacement component and a focusing component; The focusing component is used to shrink the third pulse laser beam and focus it onto the surface to be processed according to the processing requirements.

9. The laser processing device according to claim 8, It is characterized in that The displacement component is used to make the processing spot generated by the third pulse laser on the surface to be processed move with the surface to be processed in a predetermined moving manner.

10. Laser processing method, It is characterized in that include: injecting a linearly polarized first pulse laser with a specified polarization direction into the spatial light modulator; Loading a prescribed phase pattern on the spatial light modulator; According to the phase diagram, the polarization direction of the first pulsed laser is adjusted pixel by pixel in the spatial light modulator so that the linear polarization direction of the portion of the first pulsed laser passing through the gray area of ​​the phase diagram and the linear polarization direction of the portion of the first pulsed laser passing through the white area of ​​the phase diagram are perpendicular to each other, thereby obtaining a second pulsed laser; performing polarization filtering on the second pulse laser to shape the second pulse laser into a third pulse laser having a light spot of a specified pattern; The third pulse laser is focused onto the surface to be processed, and the light spot generated by the third pulse laser on the surface to be processed is moved relative to the surface to be processed in a prescribed manner, so as to process the surface to be processed.

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