Micro groove laser processing device and method

Abstract

The present application discloses a micro-groove laser processing device and method, which relates to the field of micro-groove processing technology, including: a laser light source, the laser light source is used to emit a laser beam, the laser beam includes an initial polarized light; a beam shaping module, the beam shaping module includes a half-wave plate, a spatial light modulator, and a first polarizer, the spatial light modulator is provided with a binary phase diagram, the half-wave plate is used to modulate the initial polarized light into an inclined polarized light, the spatial light modulator is used to deflect the inclined polarized light into a deflected polarized light perpendicular to each other in the selected area and the non-selected area through the binary phase diagram, the first polarizer is used to filter the deflected polarized light in the non-selected area, so as to obtain a light spot composed of the deflected polarized light in the selected area; a laser focusing module, the laser focusing module is used to control the light spot to focus on the corresponding position of the material to be processed. The present application can improve the shape freedom of micro-groove processing while improving the processing efficiency.

Description

Technical Field

[0001] The present application relates to the field of groove processing technology, and in particular to a micro-groove laser processing device and method. Background Art

[0002] In the related art, micron-level grooves, referred to as microgrooves, are used in many fields. For example, in the semiconductor field, microgroove arrays can be used as heat dissipation structures, and the cross-sectional shape of microgrooves will affect the heat dissipation performance of semiconductor devices; in the field of microfluids, microgrooves are the part that is in direct contact with the fluid, and the influence of the groove shape on the fluid pressure distribution determines the flow performance of the microfluid; therefore, the processing method of the cross-sectional shape of microgrooves is particularly important. At present, the method of processing microgrooves usually includes mechanical processing or electrospark processing of raw materials using processing tools that are adapted to the target groove shape. However, the above two processing methods are both contact processing methods. Due to problems such as process and materials, the shape of the processing tool is restricted, and thus the shape of the microgroove is also restricted, and the shape freedom of the microgroove is low; on the other hand, contact processing is easy to cause wear to the processing tool. After the processing tool is worn, if the tool is still used for continuous processing, the shape accuracy of the microgroove will be reduced, which directly affects the performance of the microgroove; if the processing tool is replaced, it will take a lot of time to replace it, which reduces the efficiency of microgroove processing. Therefore, how to improve the shape freedom and processing efficiency of micro grooves during processing has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a micro-groove laser processing device and method, which can improve the shape freedom and processing efficiency of micro-groove processing.

[0004] According to the first aspect of the present application, a micro-groove laser processing device includes:

[0005] A laser light source, the laser light source is used to emit a laser beam, wherein the laser beam is initially polarized light;

[0006] A beam shaping module, the beam shaping module comprising a half-wave plate, a spatial light modulator, and a first polarizer, the spatial light modulator is provided with a binary phase diagram, the half-wave plate is used to modulate the initial polarized light into tilted polarized light, the spatial light modulator is used to deflect the tilted polarized light into deflected polarized light perpendicular to each other in a selected area and a non-selected area through the binary phase diagram, and the first polarizer is used to filter out the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area;

[0007] A laser focusing module, wherein the laser focusing module is used to control the light spot to focus on a corresponding position of the material to be processed.

[0008] According to the micro-groove laser processing device of the embodiment of the present application, at least the following beneficial effects are achieved: by providing a laser light source, a beam shaping module, and a laser focusing module, when the laser light source emits a laser beam composed of initial polarized light, first, the beam shaping module shapes multiple initial polarized lights to obtain a target spot shape, and finally, the laser focusing module focuses the spot on the corresponding position of the material to be processed. The micro-groove laser processing device of the present application obtains the corresponding micro-groove by shaping the laser into a specific spot shape and processing the material to be processed by focusing the spot; on the one hand, different micro-groove shapes can be shaped by the beam shaping module to obtain different spot shapes and processed, and there is no need to set up a processing tool with a specific structure separately, and under a long-term processing state, there is no need to replace a new processing tool due to wear problems, and the processing efficiency is improved; on the other hand, by processing the material to be processed by shaping the spot, more diverse micro-grooves can be processed, so the shape of the micro-groove has greater freedom and is no longer limited to a specific shape. In summary, the micro-groove laser processing device of the present application can improve the freedom of the micro-groove processing shape while improving the processing efficiency.

[0009] According to some embodiments of the present application, the micro-groove laser processing device also includes a spot center adjustment module and a semi-transparent and semi-reflective lens, and the spot center adjustment module includes a second reflector, a first convex lens, a beam quality analyzer, and an angle adjustment module; the semi-transparent and semi-reflective lens is used to reflect the laser beam corresponding to a portion of the light spot to the second reflector, so that the second reflector reflects a portion of the light spot through the first convex lens to the beam quality analyzer; the beam quality analyzer is used to analyze a portion of the light spot to obtain a light intensity distribution diagram; the angle adjustment module is used to adjust the angle of the laser beam emitted by the laser light source according to the light intensity distribution diagram, so that when the laser beam passes through the binary phase diagram, the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator.

[0010] According to some embodiments of the present application, the micro-groove laser processing device also includes a liquid film control module, which is used to cover the surface of the material to be processed with a liquid film according to a set thickness; the laser focusing module is also used to control the light spot to pass through the liquid film and focus on the corresponding position of the material to be processed with the set liquid film thickness.

[0011] According to some embodiments of the present application, the liquid film control module includes a peristaltic pump, a displacement table, and a flow needle. The displacement table is provided with a water trough, which is used to fix the material to be processed and contain the liquid circulating on the surface of the material to be processed. The peristaltic pump is used to transport the liquid to the surface of the material to be processed, and the flow needle is used to control the thickness of the liquid film on the surface of the material to be processed to a set thickness.

[0012] According to some embodiments of the present application, the microgroove laser processing device also includes a focus detection module, a dichroic mirror, and a focusing modulation module; the laser focusing module includes an objective lens, and the focus detection module includes a coaxial light source, a beam splitter, a camera, and a first reflector; the coaxial light source is used to emit monochromatic light, so that the monochromatic light passes through the dichroic mirror and the objective lens in sequence after being reflected by the beam splitter, and is irradiated on the surface of the material to be processed; the camera is used to capture the monochromatic light reflected by the surface of the material to be processed and passes through the objective lens, the dichroic mirror, the beam splitter, and the first reflector in sequence to form an image corresponding to the surface of the material to be processed; the focusing modulation module is used to move the objective lens in the vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens is focused on the surface of the material to be processed.

[0013] The micro-groove laser processing method according to the second aspect of the present application is applied to a micro-groove laser processing device, and the micro-groove laser processing device includes:

[0014] A laser light source, the laser light source is used to emit a laser beam, wherein the laser beam includes initial polarized light;

[0015] A beam shaping module, the beam shaping module comprising a half-wave plate, a spatial light modulator, and a first polarizer, the spatial light modulator is provided with a binary phase diagram, the half-wave plate is used to modulate the initial polarized light into tilted polarized light, the spatial light modulator is used to deflect the tilted polarized light into deflected polarized light perpendicular to each other in a selected area and a non-selected area through the binary phase diagram, and the first polarizer is used to filter out the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area;

[0016] A laser focusing module, the laser focusing module is used to control the light spot to focus on a corresponding position of the material to be processed;

[0017] The micro-groove laser processing method comprises the following steps:

[0018] emitting the laser beam;

[0019] Modulating the initial polarized light into the tilted polarized light;

[0020] Deflecting the oblique polarized light into the deflected polarized light which is perpendicular to each other in the selected area and the non-selected area;

[0021] filtering out the deflected polarized light in the non-selected area to obtain the light spot formed by the deflected polarized light in the selected area;

[0022] The light spot is focused on the surface of the material to be processed and processed to obtain micro grooves.

[0023] According to some embodiments of the present application, the micro-groove laser processing device further includes a light spot center adjustment module and a semi-transparent and semi-reflective lens, and the light spot center adjustment module includes a second reflector, a first convex lens, a beam quality analyzer, and an angle adjustment module; the semi-transparent and semi-reflective lens is used to reflect the laser beam corresponding to a portion of the light spot to the second reflector, so that the second reflector reflects a portion of the light spot through the first convex lens to the beam quality analyzer; the beam quality analyzer is used to analyze a portion of the light spot to obtain a light intensity distribution diagram; the angle adjustment module is used to adjust the angle of the laser beam emitted by the laser light source according to the light intensity distribution diagram, so that when the laser beam passes through the binary phase diagram, the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator;

[0024] The microgroove laser processing method further comprises the following steps: adjusting the center of the light spot so that the center of the laser beam coincides with the center of the binary phase image loaded by the spatial light modulator;

[0025] The step of adjusting the center of the light spot so that the center of the laser beam coincides with the center of the binary phase image loaded by the spatial light modulator comprises the following steps:

[0026] Reflecting part of the light spot to obtain part of the light spot;

[0027] Analyzing part of the light spots to obtain the light intensity distribution diagram;

[0028] The angle at which the laser beam is emitted by the laser light source is adjusted according to the light intensity distribution diagram, so that the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator.

[0029] According to some embodiments of the present application, the micro-groove laser processing device further includes a liquid film control module, which is used to cover the surface of the material to be processed with a liquid film according to a set thickness; the laser focusing module is also used to control the light spot to pass through the liquid film and focus on the corresponding position of the material to be processed with the set liquid film thickness;

[0030] The micro-groove laser processing method further includes the following steps: covering the surface of the material to be processed with the liquid film according to a set thickness.

[0031] According to some embodiments of the present application, the liquid film control module includes a peristaltic pump, a displacement stage, and a flow needle, the displacement stage is provided with a water tank, the water tank is used to fix the material to be processed and contain the liquid circulating on the surface of the material to be processed, the peristaltic pump is used to transport the liquid to the surface of the material to be processed, and the flow needle is used to control the thickness of the liquid film on the surface of the material to be processed to a set thickness;

[0032] The step of covering the surface of the material to be processed with the liquid film according to a set thickness comprises the following steps:

[0033] transporting the liquid to the surface of the material to be processed located in the water tank;

[0034] The thickness of the liquid film on the surface of the material to be processed is controlled to a set thickness.

[0035] According to some embodiments of the present application, the micro-groove laser processing device further includes a focus detection module, a dichroic mirror, and a focus modulation module; the laser focusing module includes an objective lens, and the focus detection module includes a coaxial light source, a beam splitter, a camera, and a first reflector; the coaxial light source is used to emit monochromatic light, so that the monochromatic light passes through the dichroic mirror and the objective lens in sequence after being reflected by the beam splitter, and is irradiated on the surface of the material to be processed; the camera is used to capture the monochromatic light reflected by the surface of the material to be processed and passes through the objective lens, the dichroic mirror, the beam splitter, and the first reflector in sequence, so as to form an image corresponding to the surface of the material to be processed; the focus modulation module is used to move the objective lens in the vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens is focused on the surface of the material to be processed;

[0036] The micro-groove laser processing method further includes: adjusting the focus position of the light spot;

[0037] The adjusting the focus position of the light spot comprises the following steps:

[0038] irradiating the monochromatic light onto the surface of the material to be processed;

[0039] capturing the monochromatic light reflected by the surface of the material to be processed to form the image corresponding to the surface of the material to be processed;

[0040] The objective lens is moved in a vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens is focused on the surface of the material to be processed.

[0041] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0043] Figure 1 A schematic diagram of the structure and optical path of a micro-groove laser processing device provided in one embodiment of the present application;

[0044] Figure 2 for Figure 1 Schematic diagram of polarization direction of polarized light detected by the polarization detection position shown in ;

[0045] Figure 3 It is a schematic diagram of the processing process in which the light spot processes the material to be processed;

[0046] Figure 4 Schematic diagram of the spot shape corresponding to different ablation areas;

[0047] Figure 5 A schematic diagram illustrating the relationship between the shape of the light spot and the ablation depth during micro-groove processing;

[0048] Figure 6 It is a structural schematic diagram of the micro-groove cross section;

[0049] Figure 7 Schematic diagram of the process of micro-groove laser processing method.

[0050] Reference numerals:

[0051] Laser light source 100;

[0052] A beam shaping module 200, a half-wave plate 210, a spatial light modulator 220, a first polarizer 230, a first polarization detection position 240, a second polarization detection position 250, a third polarization detection position 260, and a fourth polarization detection position 270;

[0053] Laser focusing module 300, objective lens 310, second convex lens 320;

[0054] A light spot center adjustment module 400, a second reflecting mirror 410, a first convex lens 420, and a beam quality analyzer 430;

[0055] Transflective lens 500;

[0056] Liquid film control module 600, displacement stage 610, water tank 611, liquid 612;

[0057] Focus detection module 700, coaxial light source 710, beam splitter 720, camera 730, first reflector 740;

[0058] Dichroic mirror 800;

[0059] 900 materials to be processed. DETAILED DESCRIPTION

[0060] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0061] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0062] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0063] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0064] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0065] In the semiconductor field, an array of microgrooves is usually used as a heat dissipation device, and its cross-sectional shape characteristics will affect the heat dissipation performance of the device; in the field of microfluidics, the microgrooves are the part that is in direct contact with the fluid, and the influence of the groove shape on the distribution of fluid pressure determines the flow performance of the microfluid; in addition, microgrooves are also used in gas ratio detectors, diffraction optics and other devices. Therefore, in the above fields, processing to obtain a microgroove structure that meets the requirements is a key technical means for whether the microgrooves can achieve the corresponding functions. At present, the processing of controllable cross-section microgrooves usually adopts mechanical processing or electrolytic processing methods. Both methods require the use of tools with the corresponding shape of the designed grooves. For example, V-shaped grooves require V-shaped tools or electrodes. The wear of the processing tools will directly affect the shape accuracy of the grooves. Moreover, for hard and brittle materials such as third-generation semiconductors, traditional processing methods can no longer effectively remove materials, and the processing quality is poor or the processing efficiency is low.

[0066] As a mechanical processing method, the disadvantage of cutting micro grooves with diamond tools is that it will generate large contact stress, which is easy to cause edge collapse at the edge of hard and brittle semiconductor materials, reducing the quality of the processed surface; the discharge machining method is also a contact processing method, which requires the processing object to be conductive and is not suitable for the processing of non-conductive materials. In the above two contact processing methods, the wear and deformation of the tool or electrode will directly lead to a decrease in the accuracy of the groove shape.

[0067] Laser ablation groove technology solves the shortcomings of the above two methods of contact processing and material selectivity. As a non-contact processing method with low material selectivity and high processing accuracy, laser processing technology can be applied to high-precision processing of various materials. However, due to the Gaussian distribution of the initial spot energy, no matter how the laser processing parameters are adjusted in a single laser scan, the final micro-groove shape is limited to a symmetrical U-shape or V-shape, and the cross-sectional profile cannot be freely adjusted. The processing method of designing the scanning path according to the cross-sectional profile requires multiple scans of the laser beam, which not only reduces the processing efficiency, but also limits the groove width to at least several times the spot diameter.

[0068] Specifically, it is based on the above problems that the technical means of obtaining microgrooves through laser processing was born. As a non-contact processing method with low material selectivity and high processing accuracy, laser processing technology can be applied to various difficult processing scenarios, especially in the scenario where the material to be processed is difficult to process, and can achieve high-precision processing of the processed material. However, limited by the Gaussian energy distribution characteristics of the commonly used light spot, in order to control the groove shape, it is usually necessary to adjust the focal plane of the laser, or adjust the laser processing parameters. The laser processing parameters include single pulse energy and pulse overlap rate, thereby changing the cross-sectional morphology of the ablated groove. For a single scan, this parameter change can only obtain U-shaped or V-shaped microgrooves. These laser processing methods cannot obtain richer groove morphologies, such as grooves with T-shaped or step-shaped cross-sectional shapes.

[0069] In addition, multiple scans can be performed on the basis of a single scan. Multiple scans are effective in controlling the groove shape. For example, a beam deflection component can be added to the laser processing optical path to control the amplitude of the laser beam when it moves back and forth, thereby controlling the ablation line width. Another groove control method is to deduce the path of multiple laser scans based on the depth, width, and cross-sectional profile of the target micro-groove morphology combined with the ablation function fitting algorithm, and then manipulate the laser beam to scan and process along the path to obtain a micro-groove with the target width and cross-sectional profile.

[0070] In general, in the related art, the process of laser ablation of microgrooves is limited by the spot shape in a single scan, and can only process U-shaped or V-shaped microgrooves. The method of designing a path and superimposing a scanning path has low processing efficiency and cannot process microgrooves of a few micrometers. Based on this, the present application provides a microgroove laser processing device and method, which can process microgrooves with controllable cross-sectional shapes through a single laser scan, and control the energy distribution by shaping the initial spot, so as to achieve the purpose of ablating microgrooves with controllable cross-sectional shapes in a single laser scan.

[0071] Refer to the following Figure 1 A micro-groove laser processing device according to an embodiment of the present application is described.

[0072] It is understandable that if Figure 1 As shown, according to the present application, the micro groove laser processing device according to the present application includes:

[0073] A laser light source 100, the laser light source 100 is used to emit a laser beam, wherein the polarization of the laser beam is an initial polarized light;

[0074] A beam shaping module 200, wherein the laser beam includes an initial polarized light, and the beam shaping module 200 includes a half-wave plate 210, a spatial light modulator 220, and a first polarizer 230. The spatial light modulator 220 is provided with a binary phase diagram. The half-wave plate 210 is used to modulate the initial polarized light into an inclined polarized light. The spatial light modulator 220 is used to deflect the inclined polarized light into a deflected polarized light perpendicular to each other in a selected area and a non-selected area through the binary phase diagram. The first polarizer 230 is used to filter out the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area.

[0075] The laser focusing module 300 is used to control the light spot to focus on the corresponding position of the material 900 to be processed.

[0076] By providing a laser light source 100, a beam shaping module 200, and a laser focusing module 300, when the laser light source 100 emits a laser beam composed of initial polarized light, first, the beam shaping module 200 shapes a plurality of initial polarized lights to obtain a target spot shape, and finally, the spot is focused on the corresponding position of the material to be processed 900 by the laser focusing module 300. The microgroove laser processing device of the present application shapes the laser into a specific spot shape, and processes the material to be processed 900 by focusing the spot to obtain the corresponding microgroove; firstly, different microgroove shapes can be shaped by the beam shaping module 200 to obtain different spot shapes and processed, and there is no need to set up a processing tool with a specific structure separately, and in the long-term processing state, there is no need to replace a new processing tool due to wear problems, and the processing efficiency is improved; secondly, by processing the material to be processed 900 by shaping the spot, more diverse microgrooves can be processed, so the shape of the microgroove has a greater degree of freedom and is no longer limited to a specific shape. In summary, the micro-groove laser processing device of the present application can improve the freedom of micro-groove processing shape while improving processing efficiency.

[0077] It should be noted that the laser light source 100 may be an ultrafast laser or other pulsed lasers, and the laser beam may be a Gaussian ultrafast pulsed laser beam or other pulsed lasers emitted by the ultrafast laser.

[0078] It should be noted that the initial polarized light is horizontally polarized light, which can be understood as polarized light parallel to the horizontal plane.

[0079] It is understandable that if Figure 1As shown, the micro-groove laser processing device also includes a spot center adjustment module 400 and a semi-transparent and semi-reflective lens 500. The spot center adjustment module 400 includes a second reflector 410, a first convex lens 420, a beam quality analyzer 430, and an angle adjustment module; the semi-transparent and semi-reflective lens 500 is used to reflect the laser beam corresponding to a part of the spot to the second reflector 410, so that the second reflector 410 reflects the part of the spot through the first convex lens 420 to the beam quality analyzer 430; the beam quality analyzer 430 is used to analyze the part of the spot to obtain a light intensity distribution diagram; the angle adjustment module is used to adjust the angle of the laser beam emitted by the laser light source 100 according to the light intensity distribution diagram, so that when the laser beam passes through the binary phase diagram, the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator 220.

[0080] It is understandable that if Figure 1 As shown, the micro-groove laser processing device also includes a liquid film control module 600, which is used to cover the surface of the material to be processed 900 with a liquid film according to a set thickness; the laser focusing module 300 is also used to control the light spot to pass through the liquid film and focus on the corresponding position of the material to be processed 900 with the set liquid film thickness.

[0081] It is understandable that if Figure 1 As shown, the liquid film control module 600 includes a peristaltic pump, a displacement platform 610, and a flow needle. The displacement platform 610 is provided with a water tank 611. The water tank 611 is used to fix the material to be processed 900 and contain the liquid 612 circulating on the surface of the material to be processed 900. The peristaltic pump is used to transport the liquid 612 to the surface of the material to be processed 900. The flow needle is used to control the thickness of the liquid film on the surface of the material to be processed 900 to a set thickness.

[0082] It is understandable that if Figure 1 As shown, the micro-groove laser processing device also includes a focus detection module 700, a dichroic mirror 800, and a focus modulation module; the laser focusing module 300 includes an objective lens 310, and the focus detection module 700 includes a coaxial light source 710, a beam splitter 720, a camera 730, and a first reflector 740; the coaxial light source 710 is used to emit monochromatic light, so that the monochromatic light passes through the dichroic mirror 800 and the objective lens 310 in sequence after being reflected by the beam splitter 720, and is irradiated on the surface of the material to be processed 900; the camera 730 is used to capture the monochromatic light reflected by the surface of the material to be processed 900 and passes through the objective lens 310, the dichroic mirror 800, the beam splitter 720 and the first reflector 740 in sequence, so as to form an image corresponding to the surface of the material to be processed 900; the focus modulation module is used to move the objective lens 310 in the vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens 310 is focused on the surface of the material to be processed 900.

[0083] Combine the following Figures 1 to 6A micro-groove laser processing device according to an embodiment of the present application is described.

[0084] like Figure 1 As shown, through Figure 1 , we can get the propagation path of the laser beam, and process through this path, so it is also called the processing light path. Figure 1 The laser light source 100 is an ultrafast laser, which generates a Gaussian ultrafast pulse laser beam. Figure 2 As shown in (a), the Gaussian ultrafast pulse laser beam emitted by the laser light source 100 is a horizontally polarized laser, and the polarization direction is converted into a polarized light at 45° after passing through the half-wave plate 210, that is, Figure 2 As shown in (b); the linear polarized light in the 45° direction is modulated by the binary phase pattern loaded on the spatial light modulator 220 to be Figure 2 The light spot pattern shown in (c) is polarized light perpendicular to each other inside and outside; finally, the polarized light in one direction of the light spot is filtered by the first polarizer 230 to obtain Figure 2 Polarized light shown in (d) in the middle. The ultrafast laser is not limited to a solid laser with a central wavelength of 520 nanometers (nm), and the pulse width of the Gaussian ultrafast pulse laser beam is not limited to 300 femtoseconds (fs).

[0085] It should be noted that, in some embodiments, the single pulse energy of the laser light source 100 is controlled to be 8 μJ, the beam diameter before focusing is 6 mm, the laser repetition frequency is 5 kHz, and the scanning speed is 100 μm / s. The binary phase image loaded on the spatial light modulator 220 is a right triangle pattern.

[0086] It should be noted that the right-angled triangle laser beam after shaping is called a light spot. The light spot will pass through a 4f system, which is the laser focusing module 300. The laser focusing module 300 includes an objective lens 310 and a second convex lens 320, and is focused on the surface of the material to be processed 900. Among them, the dichroic mirror is used to reflect the right-angled triangle laser beam to the objective lens 310, so that the objective lens 310 focuses the right-angled triangle laser beam on the material to be processed 900 for processing. Because the focal length of the objective lens 310 is fixed, the up and down movement can make the focus of the objective lens 310 fall exactly on the sample surface. Therefore, by controlling the up and down movement of the objective lens 310, the focus of the right-angled triangle laser beam is moved to the surface of the material to be processed 900. The material to be processed 900 is placed in a water tank 611, and the water tank 611 is placed on a translation stage 610; wherein, the translation stage 610 can be a three-axis precision translation stage 610.

[0087] It should be noted that the coaxial light source 710 can be an LED light source. The monochromatic light emitted by the LED light source is reflected by the beam splitter 720 and then passes through the dichroic mirror 800 and the objective lens 310 in sequence to illuminate the surface of the material to be processed 900. The light reflected by the material to be processed 900 passes through the objective lens 310, the dichroic mirror 800, the beam splitter 720 and the first reflector 740 in sequence, enters the camera 730 for imaging, and obtains a photo of the sample surface, wherein the camera 730 is a CMOS camera 730. The focal position of the camera 730 imaging and the laser focal position are coaxially processed, so as to facilitate laser focus modulation through the focus modulation module, wherein the focus modulation module is a visual software; specifically, the movement of the objective lens 310 is controlled up and down by the focus modulation module.

[0088] It should be noted that the embodiment of beam shaping refers to Figure 2 , Figure 2 The four polarized lights are detected in sequence by the first polarization detection position 240, the second polarization detection position 250, the third polarization detection position 260, and the fourth polarization detection position 270. First, the initial polarized light is modulated into a linear polarized light with a polarization direction of 45°, that is, Figure 2 Then, the polarization of the laser beam outside the pattern is rotated by 90° through the binary phase image loaded on the spatial light modulator 220, forming a laser beam with orthogonal polarization inside and outside the pattern, that is, Figure 2 (b) transitions to (c); finally, the polarized light outside the pattern is blocked by the first polarizer 230, and only the laser beam inside the pattern can pass through, obtaining a laser pattern identical to the phase diagram, that is, Figure 2 (c) transitions to (d). The binary phase diagram is designed according to the grayscale of the spatial light modulator 220. First, the relationship between the phase delay and the grayscale diagram of the spatial light modulator 220 needs to be calibrated, that is, the numerical relationship between the phase and the grayscale value needs to be determined. Then, the grayscale values ​​of the pattern are set inside and outside the design pattern respectively, so that the two grayscale values ​​inside and outside the pattern just correspond to the phase delay of 0 and π, thereby realizing the rotation operation of the polarized light.

[0089] It should be noted that it is possible to choose whether to use liquid 612 to assist ablation according to the material. For materials whose ablation products are gases, such as diamond and polyimide, there is no need to add liquid 612 to assist, and only the superposition deposition of the shaping laser can process a specific groove shape; for processing objects with ablation debris such as silicon carbide and silicon, liquid 612 is required to assist ablation, and the laser-induced microjet-assisted ablation method is used to eliminate the interference of the ablation products, so that a groove of a specific shape can be processed by superposition scanning of the shaping spot.

[0090] Specifically, the water tank 611 can be an open quartz container, and the material to be processed 900 is placed in the open quartz container and fixed when in use. The open quartz container is used to hold the auxiliary liquid 612 in the laser-induced microjet-assisted ablation process. The liquid 612 is circulated and supplied by a peristaltic pump, wherein the peristaltic pump is a micro-flow pump; the outlet of the peristaltic pump is connected to a flow needle, and the liquid 612 is ejected from the flow needle to the surface of the material to be processed 900, forming a thin film of liquid 612 with a dynamically stable thickness on the surface of the processing area.

[0091] It is understandable that if Figure 3 As shown, the shaped laser beam is focused on the surface of the material 900 to be processed covered by the liquid 612 film generated by the above method through the objective lens 310. The area and thickness of the liquid 612 film formed in the processing area are controlled by changing the pump flow rate and the needle outlet diameter. What needs to be satisfied is that the thickness of the liquid 612 film should be smaller than the diameter of the laser-induced cavitation bubble, so as to achieve the condition of forming a laser-induced microjet.

[0092] It should be noted that the groove cross-section formation principle is as follows: the energy deposited on the surface of the material 900 to be processed determines the depth of ablation, and the amount of deposited energy is determined by the number of deposited laser pulses and the energy of each pulse. During the laser scanning ablation process, the energy of the laser pulse remains unchanged, so changing the number of pulses deposited at various locations on the material surface can ablate different depths at different locations. Figure 4 The schematic diagram of the effective pulse number calculation principle is given. When the spot shape is as follows Figure 4 (e) When the triangular spot is at Figure 4 The effective pulse number N at each position of the ablation area at (f) can be calculated according to the following formula:

[0093] N=h□f / v

[0094] Among them, h is the size of the triangular spot corresponding to each position of the material ablation area in the scanning direction. The scanning direction is the length direction of the micro-groove, that is, the y-axis direction; f is the repetition frequency of the laser, that is, the number of laser pulses in one second; v is the scanning speed of the laser; H is the length of the right angle side of the triangular spot in the length direction, and W is the length of the right angle side of the triangular spot in the width direction. The width direction can be understood as the x-axis direction.

[0095] Specifically, taking a triangular spot as an example, the length of the spot in the scanning direction changes linearly, resulting in a linear change in the number of effective pulses at each position in the ablation area of ​​the material. If the energy of a single pulse remains unchanged, the ablation depth will also change linearly, and eventually a triangular groove will be formed by ablation.

[0096] It should be noted that Figure 4The triangular spot is discretized in the x direction and simplified into a three-level step spot, such as Figure 5 In the structural arrangement shown in (g), h1, h2, and h3 represent the lengths of different rows of light spots, and the number of pulses in each row is controlled by the length of h.

[0097] It should be noted that, assuming Figure 5 The diagram shown in (h) is the superposition diagram of the light spot in the scanning direction, that is, the superposition diagram of the light spot scanning in three steps along the positive direction of the y-axis. c1, c2, c3, b1, b2, b3, a1, a2, and a3 are used to indicate the number of pulses that have been superimposed in different processing areas, and the number of pulses is controlled by the length of h. Figure 5 As shown in (h), the number of pulses superimposed at the three positions a1, b1, and c1 are 1, 2, and 3 respectively; similarly, the number of pulses superimposed at a2, b2, c2 and a3, b3, and c3 in subsequent scans are 1, 2, and 3 respectively. Since the ablation depth of each pulse is equal, the position with more superimposed pulses has a deeper ablation depth, so we can get the following: Figure 5 (i) shows the structure at different depths in the z direction.

[0098] The above-mentioned micro-groove laser processing device is used for beam shaping and liquid 612-assisted ablation. The spot shape is designed and the appropriate laser pulse energy and scanning parameters are adjusted to ablate the following on a 200 μm thick single-crystal silicon carbide wafer: Figure 6 The microgrooves shown, among which (j) and (n) are a group, (k) and (o) are a group, (l) and (p) are a group, and (m) and (q) are a group, represent triangular, W-shaped, stepped and T-shaped microgrooves, respectively.

[0099] The microgroove laser processing device provided by the present invention and the method implemented by the microgroove laser processing device can realize laser scanning processing of microgrooves with controllable cross-sections, reduce recasting and adhesion of ablation products, improve the ablation quality of the microgrooves, and realize microgroove processing with freely adjustable cross-sectional shapes.

[0100] Combine the following Figure 7 The micro-groove laser processing method according to an embodiment of the present application is described.

[0101] It is understandable that if Figure 7 As shown, a micro-groove laser processing method is provided, which is applied to a micro-groove laser processing device, and the micro-groove laser processing device includes:

[0102] A laser light source 100, the laser light source 100 is used to emit a laser beam, wherein the polarization of the laser beam is an initial polarized light;

[0103] A beam shaping module 200, wherein the laser beam includes an initial polarized light, and the beam shaping module 200 includes a half-wave plate 210, a spatial light modulator 220, and a first polarizer 230. The spatial light modulator 220 is provided with a binary phase diagram. The half-wave plate 210 is used to modulate the initial polarized light into an inclined polarized light. The spatial light modulator 220 is used to deflect the inclined polarized light into a deflected polarized light perpendicular to each other in a selected area and a non-selected area through the binary phase diagram. The first polarizer 230 is used to filter out the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area.

[0104] A laser focusing module 300, which is used to control the light spot to focus on a corresponding position of the material to be processed 900;

[0105] The micro-groove laser processing method comprises the following steps:

[0106] emit a laser beam;

[0107] Modulating the initial polarized light into tilted polarized light;

[0108] deflecting the oblique polarized light into deflected polarized light perpendicular to each other in the selected area and the non-selected area;

[0109] Filtering the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area;

[0110] The light spot is focused on the surface of the material to be processed 900 and processed to obtain micro grooves.

[0111] It can be understood that the micro-groove laser processing device also includes a spot center adjustment module 400 and a semi-transparent and semi-reflective lens 500. The spot center adjustment module 400 includes a second reflector 410, a first convex lens 420, a beam quality analyzer 430, and an angle adjustment module; the semi-transparent and semi-reflective lens 500 is used to reflect the laser beam corresponding to a part of the spot to the second reflector 410, so that the second reflector 410 reflects the part of the spot through the first convex lens 420 to the beam quality analyzer 430; the beam quality analyzer 430 is used to analyze the part of the spot to obtain a light intensity distribution diagram; the angle adjustment module is used to adjust the angle of the laser beam emitted by the laser light source 100 according to the light intensity distribution diagram, so that when the laser beam passes through the binary phase diagram, the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator 220;

[0112] The micro-groove laser processing method further includes the following steps: adjusting the center of the light spot so that the center of the laser beam coincides with the center of the binary phase image loaded by the spatial light modulator 220;

[0113] Adjusting the center of the light spot so that the center of the laser beam coincides with the center of the binary phase image loaded by the spatial light modulator 220 includes the following steps:

[0114] Reflect part of the light spot to obtain part of the light spot;

[0115] Analyze part of the light spot to obtain a light intensity distribution diagram;

[0116] The angle of the laser beam emitted by the laser light source 100 is adjusted according to the light intensity distribution diagram so that the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator 220 .

[0117] It can be understood that the micro-groove laser processing device further includes a liquid film control module 600, which is used to cover the surface of the material to be processed 900 with a liquid film according to a set thickness; the laser focusing module 300 is also used to control the light spot to pass through the liquid film and focus on the corresponding position of the material to be processed 900 with the set liquid film thickness;

[0118] The micro-groove laser processing method further includes the following steps: covering the surface of the material to be processed 900 with a liquid film according to a set thickness.

[0119] It can be understood that the liquid film control module 600 includes a peristaltic pump, a displacement stage 610, and a flow needle. The displacement stage 610 is provided with a water tank 611. The water tank 611 is used to fix the material to be processed 900 and contain the liquid 612 circulating on the surface of the material to be processed 900. The peristaltic pump is used to transport the liquid 612 to the surface of the material to be processed 900. The flow needle is used to control the thickness of the liquid film on the surface of the material to be processed 900 to a set thickness.

[0120] The liquid film is covered on the surface of the material to be processed 900 according to a set thickness, including the following steps:

[0121] The liquid 612 is delivered to the surface of the material 900 to be processed located in the water tank 611;

[0122] The thickness of the liquid film on the surface of the material 900 to be processed is controlled to a set thickness.

[0123] It can be understood that the micro-groove laser processing device further includes a focus detection module 700, a dichroic mirror 800, and a focus modulation module; the laser focusing module 300 includes an objective lens 310, and the focus detection module 700 includes a coaxial light source 710, a beam splitter 720, a camera 730, and a first reflector 740; the coaxial light source 710 is used to emit monochromatic light, so that the monochromatic light passes through the dichroic mirror 800 and the objective lens 310 in sequence after being reflected by the beam splitter 720, and is irradiated on the surface of the material to be processed 900; the camera 730 is used to capture the monochromatic light reflected by the surface of the material to be processed 900 and passes through the objective lens 310, the dichroic mirror 800, the beam splitter 720 and the first reflector 740 in sequence, so as to form an image corresponding to the surface of the material to be processed 900; the focus modulation module is used to move the objective lens 310 in the vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens 310 is focused on the surface of the material to be processed 900;

[0124] The micro-groove laser processing method further includes: adjusting the focus position of the light spot;

[0125] Adjusting the focus position of the light spot includes the following steps:

[0126] Irradiating monochromatic light onto the surface of the material to be processed 900;

[0127] Capturing monochromatic light reflected by the surface of the material to be processed 900 to form an image corresponding to the surface of the material to be processed 900;

[0128] The objective lens 310 is moved in the vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens 310 is focused on the surface of the material 900 to be processed.

[0129] It should be noted that the focus detection module 700 of the present invention can keep the plane where the laser focus is located (referred to as the focal plane) on the sample surface regardless of whether the sample surface is covered with a liquid film. Because the positioning of the laser focal plane is achieved by a coaxial light source 710 and a camera 730, that is, the combined positioning of a coaxial illumination LED (central wavelength 650nm) and a CMOS camera 730, it has the same focal plane as the focused laser beam (central wavelength 520nm). Therefore, it can be ensured that the laser focal plane is on the sample surface.

[0130] The micro-groove laser processing method of the present application is further described below.

[0131] The present invention aims to solve the key technical problems of controllable processing of micro-groove cross-sectional profile. Specifically, two problems are solved. One is that the ablation products are retained in the laser processing area and affect the subsequent laser energy deposition; the other is to shape the light spot and adjust the pulse overlap rate at various locations in the groove by the light spot shape. To this end, the present invention proposes a groove processing device and method for shaping laser-induced microjet-assisted ablation, which can quickly discharge the ablation products, avoid the deposition of ablation particles, and obtain a groove cross-section similar to the light spot shape.

[0132] The specific steps are as follows:

[0133] Step 1: Use an ultrafast laser to generate an ultrafast pulsed Gaussian laser beam.

[0134] Step 2: Use the half-wave plate 210 to modulate the initial polarized light output by the laser light source 100 into polarized light that forms an angle of 45° with the horizontal direction.

[0135] Step 3: Load a binary phase map on the spatial light modulator 220. The grayscale values ​​inside and outside the pattern on the binary phase map are different, corresponding to the phase delays of 180° and 0° of the phase-type spatial light modulator 220, respectively. Irradiate the 45° linearly polarized laser in the aforementioned step 2 to the area where the binary phase map is loaded on the spatial light modulator 220. After the laser inside and outside the area experiences different phase delays, the polarization direction is deflected accordingly. Finally, the spot pattern modulated by the spatial light modulator 220 has mutually perpendicular polarized light inside and outside.

[0136] Step 4: Screen the modulated laser polarization using the first polarizer 230. The first polarizer 230 only allows polarization in one direction to pass through, and can completely retain only the polarization inside or outside the pattern, thereby obtaining a laser spot that is the same as the designed pattern.

[0137] It should be noted that the laser beam shaping method does not only include the method of loading a binary phase through the spatial light modulator 220. Other methods such as loading a holographic phase map through the spatial light modulator 220 to generate a light spot of a specific shape, and using this shaped light spot to scan and process the groove cross section utilizes the same ablation pulse superposition principle, which also belongs to the derivative method of the present invention.

[0138] Step 5: When it is necessary to lay a liquid film for processing, use the liquid film control module 600 to form a liquid film of a specific thickness in the processing area of ​​the material to be processed 900. First, use a peristaltic pump to pump the liquid 612 contained in the open quartz container into the liquid 612 nozzle, and the liquid 612 in the nozzle is ejected through the flow needle. The liquid 612 passes through the nozzle at a specific flow rate to form a liquid 612 jet with controllable speed. The liquid 612 jet impacts the surface of the material to be processed 900 at a certain angle, and will form a layer of dynamically stable thin liquid film. The thickness of the stable liquid 612 film area is one tenth of the nozzle diameter. The present invention adjusts the thickness of the processing liquid film by selecting the nozzle diameter to match it with the energy of the single laser pulse, and finally allows the laser-induced cavitation bubbles to collapse asymmetrically at this liquid film thickness. Asymmetric collapse specifically refers to the liquid film thickness being smaller than the diameter of the laser-induced cavitation bubble. In this case, the upper surface of the spherical cavitation bubble generated by the laser piercing the liquid 612 is at the interface between the air and the liquid 612, and the movement of the bubble and the flow field around it will change to meet the corresponding boundary conditions. Therefore, when the bubble moves near the boundary, the pressure generated by the boundary will cause the bubble to preferentially break in the direction perpendicular to the boundary, which is an asymmetric collapse phenomenon.

[0139] Step 6: The shaped laser beam passes through the 4f system composed of the second convex lens 320 and the objective lens 310, that is, the laser focusing module 300, and is focused on the surface of the material to be processed 900 covered by the thin liquid film. The laser beam irradiates the surface of the material to be processed 900, causing the material to be processed 900 to be ablated. Figure 3 As shown, the laser induces cavitation bubbles in the liquid 612, and the cavitation bubbles collapse asymmetrically under the action of the free boundary, generating a high-speed microjet in the opposite direction of the laser scanning direction. The microjet carries the debris generated by ablation and the residual bubbles to move backward and fly away from the ablation area.

[0140] Step 7: In a processing environment without debris and residual bubbles, the shaped spot is used for scanning processing. The number of effective pulses accumulated at different positions of the scanning section is linearly related to the spot size. The different number of local accumulated effective pulses causes the ablation depth at various positions of the groove section to vary accordingly.

[0141] The micro-groove laser processing method of the present application can also detect and adjust the spot energy distribution, the purpose is to ensure that the laser center coincides with the binary phase diagram center and maximize the use of the energy of the spot center. The specific implementation steps are:

[0142] Step 1: Use the semi-transparent and semi-reflective lens 500 to reflect a portion of the shaped light spot energy from the main light path to the beam quality analyzer 430;

[0143] Step 2: Use the beam quality analyzer 430 to collect reflected light energy and form a light intensity distribution image;

[0144] Step 3: The angle between the incident laser and the spatial light modulator 220 is adjusted by the angle adjustment module so that the center of the laser coincides with the center of the pattern of the binary phase diagram, thereby obtaining a shaped light spot with uniform energy distribution.

[0145] It should be noted that the semi-transparent and semi-reflective lens 500 of the present invention reflects a part of the light to the beam quality analyzer 430. Through the online observation of the energy intensity of the reflected light spot, the coincidence of the light spot with the pattern center of the binary phase diagram can be accurately controlled.

[0146] Based on the above description, the present invention has the following effects:

[0147] Firstly, compared with conventional machining, electrical discharge machining and other technologies: the present invention does not cause loss of machining tools; the groove shape can be changed according to the loaded phase diagram without the need for customized special tools.

[0148] Secondly, compared with the technology of changing laser processing parameters to ablate grooves: the groove shapes that can be processed by the present invention are not limited to U-shape and V-shape, and the shape has greater freedom.

[0149] Thirdly, compared with multiple scanning laser ablation with superimposed scanning paths: the present invention can process micron-level controllable grooves through a single scanning process, thereby improving processing efficiency.

[0150] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A micro-groove laser processing device, characterized in that: include: A laser light source, the laser light source is used to emit a laser beam, wherein the polarization of the laser beam is initial polarized light; A beam shaping module, the beam shaping module comprising a half-wave plate, a spatial light modulator, and a first polarizer, the spatial light modulator is provided with a binary phase diagram, the half-wave plate is used to modulate the initial polarized light into tilted polarized light, the spatial light modulator is used to deflect the tilted polarized light into deflected polarized light perpendicular to each other in a selected area and a non-selected area through the binary phase diagram, and the first polarizer is used to filter out the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area; A laser focusing module, which is used to control the light spot to focus on a corresponding position of the material to be processed; The micro-groove laser processing device also includes a spot center adjustment module and a semi-transparent and semi-reflective lens. The spot center adjustment module includes a second reflector, a first convex lens, a beam quality analyzer, and an angle adjustment module; the semi-transparent and semi-reflective lens is used to reflect the laser beam corresponding to a portion of the spot to the second reflector, so that the second reflector reflects a portion of the spot through the first convex lens to the beam quality analyzer; the beam quality analyzer is used to analyze a portion of the spot to obtain a light intensity distribution diagram; the angle adjustment module is used to adjust the angle of the laser beam emitted by the laser light source according to the light intensity distribution diagram, so that when the laser beam passes through the binary phase diagram, the center of the laser beam coincides with the center of the binary phase diagram.

2. The micro-groove laser processing device according to claim 1, characterized in that: The micro-groove laser processing device also includes a liquid film control module, which is used to cover the surface of the material to be processed with a liquid film according to a set thickness; the laser focusing module is also used to control the light spot to pass through the liquid film and focus on the corresponding position of the material to be processed with the set liquid film thickness.

3. The micro-groove laser processing device according to claim 2, characterized in that: The liquid film control module includes a peristaltic pump, a displacement platform, and a flow needle. The displacement platform is provided with a water tank, which is used to fix the material to be processed and contain the liquid circulating on the surface of the material to be processed. The peristaltic pump is used to transport the liquid to the surface of the material to be processed, and the flow needle is used to control the thickness of the liquid film on the surface of the material to be processed to a set thickness.

4. The micro-groove laser processing device according to claim 1, characterized in that: The micro-groove laser processing device further includes a focus detection module, a dichroic mirror, and a focus modulation module; the laser focusing module includes an objective lens, and the focus detection module includes a coaxial light source, a beam splitter, a camera, and a first reflector; the coaxial light source is used to emit monochromatic light, so that the monochromatic light passes through the dichroic mirror and the objective lens in sequence after being reflected by the beam splitter, and is irradiated on the surface of the material to be processed; the camera is used to capture the monochromatic light reflected by the surface of the material to be processed and passes through the objective lens, the dichroic mirror, the beam splitter, and the first reflector in sequence, so as to form an image corresponding to the surface of the material to be processed; The focus modulation module is used to move the objective lens in the vertical direction according to the image, so that the focus formed by the light spot passing through the objective lens is focused on the surface of the material to be processed.

5. A micro-groove laser processing method, characterized in that: Applicable to a micro-groove laser processing device, the micro-groove laser processing device comprises: A laser light source, the laser light source is used to emit a laser beam, wherein the polarization of the laser beam is initial polarized light; A beam shaping module, the beam shaping module comprising a half-wave plate, a spatial light modulator, and a first polarizer, the spatial light modulator is provided with a binary phase diagram, the half-wave plate is used to modulate the initial polarized light into tilted polarized light, the spatial light modulator is used to deflect the tilted polarized light into deflected polarized light perpendicular to each other in a selected area and a non-selected area through the binary phase diagram, and the first polarizer is used to filter out the deflected polarized light in the non-selected area to obtain a light spot composed of the deflected polarized light in the selected area; A laser focusing module, which is used to control the light spot to focus on a corresponding position of the material to be processed; The micro-groove laser processing method comprises the following steps: emitting the laser beam; Modulating the initial polarized light into the tilted polarized light; Deflecting the oblique polarized light into the deflected polarized light which is perpendicular to each other in the selected area and the non-selected area; filtering out the deflected polarized light in the non-selected area to obtain the light spot formed by the deflected polarized light in the selected area; Focusing the light spot on the surface of the material to be processed and processing the surface to obtain micro grooves; The micro-groove laser processing device also includes a light spot center adjustment module and a semi-transparent and semi-reflective lens, wherein the light spot center adjustment module includes a second reflector, a first convex lens, a beam quality analyzer, and an angle adjustment module; the semi-transparent and semi-reflective lens is used to reflect the laser beam corresponding to a part of the light spot to the second reflector, so that the second reflector reflects a part of the light spot to the beam quality analyzer through the first convex lens; the beam quality analyzer is used to analyze a part of the light spot to obtain a light intensity distribution diagram; the angle adjustment module is used to adjust the angle of the laser beam emitted by the laser light source according to the light intensity distribution diagram, so that when the laser beam passes through the binary phase diagram, the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator; The microgroove laser processing method further comprises the following steps: adjusting the center of the light spot so that the center of the laser beam coincides with the center of the binary phase image loaded by the spatial light modulator; The step of adjusting the center of the light spot so that the center of the laser beam coincides with the center of the binary phase image loaded by the spatial light modulator comprises the following steps: Reflecting part of the light spot to obtain part of the light spot; Analyzing part of the light spots to obtain the light intensity distribution diagram; The angle at which the laser beam is emitted by the laser light source is adjusted according to the light intensity distribution diagram, so that the center of the laser beam coincides with the center of the binary phase diagram loaded by the spatial light modulator.

6. The micro-groove laser processing method according to claim 5, characterized in that: The micro-groove laser processing device further includes a liquid film control module, which is used to cover the surface of the material to be processed with a liquid film according to a set thickness; the laser focusing module is also used to control the light spot to pass through the liquid film and focus on the corresponding position of the material to be processed with the set liquid film thickness; The micro-groove laser processing method further includes the following steps: covering the surface of the material to be processed with the liquid film according to a set thickness.

7. The micro-groove laser processing method according to claim 6, characterized in that: The liquid film control module includes a peristaltic pump, a displacement platform, and a flow needle. The displacement platform is provided with a water tank, the water tank is used to fix the material to be processed and contain the liquid circulating on the surface of the material to be processed, the peristaltic pump is used to transport the liquid to the surface of the material to be processed, and the flow needle is used to control the thickness of the liquid film on the surface of the material to be processed to a set thickness; The step of covering the surface of the material to be processed with the liquid film according to a set thickness comprises the following steps: transporting the liquid to the surface of the material to be processed located in the water tank; The thickness of the liquid film on the surface of the material to be processed is controlled to a set thickness.

8. The micro-groove laser processing method according to claim 5, characterized in that: The micro-groove laser processing device further includes a focus detection module, a dichroic mirror, and a focus modulation module; the laser focusing module includes an objective lens, and the focus detection module includes a coaxial light source, a beam splitter, a camera, and a first reflector; the coaxial light source is used to emit monochromatic light, so that the monochromatic light passes through the dichroic mirror and the objective lens in sequence after being reflected by the beam splitter, and is irradiated on the surface of the material to be processed; the camera is used to capture the monochromatic light reflected by the surface of the material to be processed and passes through the objective lens, the dichroic mirror, the beam splitter, and the first reflector in sequence, so as to form an image corresponding to the surface of the material to be processed; The focus modulation module is used to move the objective lens in the vertical direction according to the image, so that the focus formed by the light spot passing through the objective lens is focused on the surface of the material to be processed; The micro-groove laser processing method further includes: adjusting the focus position of the light spot; The adjusting the focus position of the light spot comprises the following steps: irradiating the monochromatic light onto the surface of the material to be processed; capturing the monochromatic light reflected by the surface of the material to be processed to form the image corresponding to the surface of the material to be processed; The objective lens is moved in a vertical direction according to the image, so that the focus formed after the light spot passes through the objective lens is focused on the surface of the material to be processed.

Images