Double-pulse-width laser-assisted water jet machining method and device

Abstract

The invention provides a double-pulse-width laser-assisted water jet machining method and device, and belongs to the technical field of laser machining. The method comprises the steps that a laser device and a water pump are started, so that a femtosecond laser beam, a nanosecond laser beam and a jet beam point to a preset moving path, and machining is started; the workpiece moves according to a preset path, and the femtosecond laser beam machines the to-be-machined surface of the workpiece to form a micro-texture; the jet flow beam forms a flowing water layer on the to-be-machined surface, and the flowing water layer is used for removing chips on the surface of the microstructure; a nanosecond laser beam is used for machining a specified shape on the surface of the micro-texture, and a jet beam is used for removing a softened material; the micro-texture is formed on the to-be-machined surface of the workpiece through the femtosecond laser beam, the microstructure of the machined surface is changed, the light transmittance is reduced, and the problem that the machined position cracks due to the fact that the high-energy nanosecond laser beam or the femtosecond laser beam is adopted for direct machining is solved; and then a nanosecond laser beam is adopted to assist a jet beam to further machine a microgroove in the surface of the micro-texture, so that the surface of the microgroove is smoother and smoother, and the product yield is improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser processing, and in particular to a dual-pulse width laser-assisted water jet processing method and device. Background Art

[0002] Common transparent hard and brittle semiconductor materials include oxide semiconductors and nitride semiconductors. They are widely used in transparent displays, solar cells, sensors and other fields because of their superior electrical and physical properties. However, the brittleness of the materials makes them prone to breakage or cracking during processing. For this problem, laser-assisted water jet processing technology is a better solution. Laser radiation is used to increase the surface temperature of the material and reduce the hardness of the material in the processing area. High-pressure water jets are then used to assist in removing the softened material to reduce cracking problems caused by the processing of hard and brittle materials.

[0003] Although the above scheme is applicable to most common transparent hard and brittle semiconductor materials, when processing transparent hard and brittle semiconductor materials with low absorption rate, due to their strong brittleness and low laser absorption rate, the existing method of using a single laser processing is still prone to edge cracking at the processing position or the workpiece cannot absorb laser energy, making it difficult to obtain high aspect ratio micro-grooves with excellent surface quality, and the product yield is low. Summary of the invention

[0004] In order to overcome the problems existing in the related art, one of the purposes of the present invention is to provide a dual-pulse laser-assisted water jet processing method, which uses two laser-assisted jet beams with different pulse widths and wavelengths to process. Micro-textures are first formed on the surface to be processed of the workpiece, the microstructure of the workpiece surface is changed, the roughness of the surface to be processed is increased, and the transmittance is reduced, so that the energy of the nanosecond laser beam can be effectively absorbed by the workpiece, and then the nanosecond laser beam is used to assist the jet beam to further process high aspect ratio microgrooves on the micro-textured surface, so as to obtain high aspect ratio microgrooves with excellent surface quality and improve the product yield.

[0005] The dual-pulse width laser-assisted water jet processing method comprises the following steps:

[0006] S1. Calibrate the laser focus, start the laser and the water pump, point the femtosecond laser beam, nanosecond laser beam and jet beam to the preset processing starting point moving path and start processing;

[0007] S2, the workpiece moves along a preset path, and the femtosecond laser beam processes the surface to be processed of the workpiece to form a micro texture;

[0008] S3, the jet beam forms a flowing water layer on the surface to be processed, and the flowing water layer is used to remove debris on the micro-textured surface;

[0009] S4. The nanosecond laser beam processes a specified shape on the micro-textured surface, and the jet beam removes the softened material.

[0010] The transparent property of low-absorption transparent hard-brittle semiconductor materials makes their absorption rate for lower energy lasers lower. Therefore, when the prior art uses femtosecond laser beams or high-energy nanosecond laser beams to directly process high aspect ratio microgrooves, the processing edge will be seriously damaged due to excessive energy density per unit area. The present method uses two laser-assisted jet beam processing with different pulse widths and wavelengths. First, a femtosecond laser beam is used to form a microtexture on the workpiece surface to be processed, change the microstructure of the workpiece surface, increase the roughness of the surface to be processed, and reduce the transmittance, so that the nanosecond laser beam energy can be effectively absorbed by the workpiece, providing conditions for further processing of lossless high aspect ratio microgrooves. At the same time, the jet beam forms a flowing water layer on the surface to be processed to promptly remove debris on the micro-texture surface, ensuring a stable processing process. Then, a nanosecond laser beam is used to assist the jet beam to process a specified shape on the micro-texture surface, such as a high aspect ratio microgroove. Nanosecond laser beam radiation increases the surface temperature of the workpiece and reduces the mechanical properties of the material. The material softened by the laser is removed by the jet beam impact, making the processing shape more precise and the surface smoother and flatter, thereby improving the processing quality.

[0011] In a preferred technical solution of the present invention, the laser includes a femtosecond laser and a nanosecond laser;

[0012] S1 specific steps include:

[0013] Calibrate the laser focus, start the femtosecond laser, and point the femtosecond laser beam to the preset processing starting point to start processing;

[0014] Start the nanosecond laser and the water pump, so that the nanosecond laser beam and the jet beam act together on the processing connection point;

[0015] The processing connection point is located on a preset processing starting point moving path.

[0016] After calibrating the laser focus, the femtosecond laser beam is pointed to the preset processing starting point to start processing the microtexture. At this time, the nanosecond laser beam and the jet beam act together on the processing connection point. Since the processing connection point is located on the moving path of the preset processing starting point, as the workpiece moves, the microtexture is formed and moves to the working area of ​​the nanosecond laser beam and the jet beam for further fine processing, forming continuous collaborative processing and improving processing efficiency.

[0017] In a preferred technical solution of the present invention, in S2, the surface to be processed of the workpiece is modified by a laser roughening method to form the micro-texture, and the micro-textured surface is used as a processing connection surface for processing a specified shape.

[0018] The surface to be processed of the workpiece is modified by laser roughening to form a micro-texture, which provides an ideal processing connection surface for subsequent processing of the specified shape, so as to obtain better processing effects.

[0019] In a preferred technical solution of the present invention, in the step of calibrating the laser focus S1, the focal plane of the femtosecond laser beam is calibrated to a position below the surface to be processed of the workpiece;

[0020] The focal plane of the nanosecond laser beam is calibrated to coincide with the surface of the workpiece to be processed.

[0021] The position of the focal plane of the femtosecond laser beam affects the depth and width of the roughening of the surface to be processed. Shallow depth and moderate width are preferred. When its focal plane is above the surface to be processed of the workpiece, the laser beam has no focal point on the surface to be processed and cannot be processed effectively. When its focal plane is at or below the surface to be processed of the workpiece, the larger the spot size is, the more dispersed the energy is, and the shallower and wider the micro-texture is. The optimal roughening effect is obtained when the focal plane of the femtosecond laser beam is below the surface to be processed of the workpiece and the vertical distance from the surface to be processed is 0.2 mm. The focal plane of the nanosecond laser beam is calibrated to coincide with the surface to be processed of the workpiece to ensure that the nanosecond laser beam can act on the surface to be processed with the best energy density and focusing performance during the processing, thereby achieving precise processing of the workpiece.

[0022] In a preferred technical solution of the present invention, the processing equipment needs to be adjusted before the step S1 is started, and the processing equipment also includes a three-axis motion platform, a jet nozzle, and a laser cutting head that emits a femtosecond laser beam and a nanosecond laser beam;

[0023] The specific steps of adjusting the processing equipment include:

[0024] Adjust the laser cutting head and jet nozzle to the top of the three-axis motion platform;

[0025] The laser cutting head is calibrated so that the laser can focus vertically on the processing horizontal reference plane;

[0026] Adjust the relative position of the femtosecond laser and the nanosecond laser;

[0027] Adjust the relative position of the laser cutting head and the jet nozzle so that the laser beam and the jet beam are in the same vertical plane;

[0028] Install the workpiece on a three-axis motion platform;

[0029] The position of the workpiece is adjusted through the three-axis motion platform to make the surface to be processed coincide with the processing horizontal reference plane.

[0030] Calibrate the laser cutting head so that it can focus vertically on the processing horizontal reference plane to ensure the accuracy of the starting point and direction; adjust the relative positions of the femtosecond laser and the nanosecond laser, as well as the laser cutting head and the jet nozzle, so that the laser beam and the jet beam are in the same vertical plane, ensuring that the laser beam and the jet beam can accurately act on the same area of ​​the workpiece during processing to achieve the purpose of collaborative processing; the adjustment of the processing equipment provides the basis for achieving high-precision and high-quality processing, making subsequent processing smoother and more accurate, thereby improving processing efficiency and finished product quality.

[0031] In a preferred technical solution of the present invention, the adjusting the relative position of the femtosecond laser and the nanosecond laser includes adjusting the femtosecond laser beam spot and the nanosecond laser beam spot to not overlap each other, and both the femtosecond laser beam spot and the nanosecond laser beam spot are located on a preset processing starting point moving path.

[0032] The two light spots are adjusted to not overlap but to be located on the preset processing starting point moving path, so that the two laser beams can be connected and work together in an orderly manner during the processing.

[0033] In a preferred technical solution of the present invention, the adjusting the relative position between the laser cutting head and the jet nozzle also includes opening the jet nozzle and adjusting the angle between the jet beam and the normal of the surface to be processed, and the angle is preferably 45°;

[0034] Adjust the offset distance between the jet beam incident point and the center point of the nanosecond laser beam spot.

[0035] When the angle between the jet beam and the normal of the surface to be processed is 45°, the jet beam can impact the surface to be processed at the optimal angle, effectively removing the softened material and debris generated during the processing, while reducing damage to the surface to be processed, ensuring the quality of the finished product and surface smoothness; the appropriate offset distance makes the jet beam incident point and the center point of the nanosecond laser beam spot staggered to avoid direct overlap and mutual interference between the two, so that both the nanosecond laser beam and the jet beam can be processed more accurately to meet the processing requirements.

[0036] In a preferred technical solution of the present invention, the femtosecond laser beam spot, the nanosecond laser beam spot, and the jet beam incident point are arranged in a straight line along the machining direction on the workpiece surface to be machined;

[0037] The workpiece processing direction is the moving direction of the three-axis motion platform, which moves from the side close to the femtosecond laser beam spot to the side close to the jet beam incident point;

[0038] The micro texture is formed by femtosecond laser beam processing and then moved to a nanosecond laser beam and a jet beam processing position for further processing into a designated shape.

[0039] Arranging the femtosecond laser beam spot, nanosecond laser beam spot, and jet beam incident points in a straight line along the machining direction on the workpiece's machining surface can achieve efficient coordination and orderly connection of the machining process; the femtosecond laser beam first acts on the preset machining starting point to roughen the machining surface to form a micro-texture; the nanosecond laser beam and jet beam accurately process the specified shape on the roughened machining surface; the jet beam uses high-pressure water flow to promptly remove the debris and softened materials generated during the machining process to ensure that the finished product has higher precision.

[0040] In a preferred technical solution of the present invention, the straight-line distance between the center point of the femtosecond laser beam spot and the center point of the nanosecond laser beam spot is the straight-line distance between the preset processing starting point and the processing connection point;

[0041] S1 to S4 all use deionized water as the jet beam medium;

[0042] The water pump is preferably a constant pressure water pump.

[0043] Deionized water has the characteristics of high purity and low conductivity, which can effectively avoid the introduction of impurities or electrochemical corrosion during the processing and ensure the purity of the finished product surface; the constant pressure water pump can provide stable pressure output, ensuring that the pressure of the jet beam is constant during the processing and the impact force on the workpiece is uniform and consistent, thereby improving processing stability.

[0044] The second object of the present invention is to provide a dual-pulse width laser-assisted water jet processing device, comprising a controller, a composite cutting assembly and a dual-pulse width laser assembly, wherein the composite cutting assembly and the dual-pulse width laser assembly are used to process a surface to be processed to form a micro texture and to process a specified shape, a three-axis motion platform is installed below the composite cutting assembly, and the composite cutting assembly, the dual-pulse width laser assembly and the three-axis motion platform are all electrically connected to the controller;

[0045] The composite cutting assembly includes a laser cutting head and a jet nozzle. The laser cutting head is provided with two, respectively emitting a femtosecond laser beam and a nanosecond laser beam for processing. The jet nozzle is connected to a water pump to spray a jet beam at high pressure, and the jet beam medium is deionized water.

[0046] The dual-pulse width laser assembly comprises a nanosecond laser and a nanosecond laser beam expander, wherein the nanosecond laser and the nanosecond laser beam expander are installed on the same vertical line with one of the laser cutting heads, and the nanosecond laser beam expander transmits the nanosecond laser beam to the laser cutting head;

[0047] The dual-pulse width laser assembly further comprises a femtosecond laser and a femtosecond laser beam expander, wherein the femtosecond laser and the femtosecond laser beam expander are both mounted on one side of the nanosecond laser and the nanosecond laser beam expander, and the femtosecond laser and the femtosecond laser beam expander are both mounted on the same vertical line as the other laser cutting head, and the femtosecond laser beam expander transmits the femtosecond laser beam to the laser cutting head;

[0048] A transparent hard and brittle material workpiece with low absorption rate is installed on the three-axis moving platform;

[0049] A jet waste liquid recovery tank is arranged below the three-axis motion platform.

[0050] The dual-pulse laser-assisted water jet processing device uses a controller to precisely control the composite cutting component and the dual-pulse laser component to achieve the purpose of roughening and modifying the workpiece surface to be processed and processing the specified shape; the laser cutting head in the composite cutting component simultaneously emits a femtosecond laser beam and a nanosecond laser beam. The femtosecond laser beam first performs roughening and modification on the workpiece surface to form a micro-texture and improve the light absorption performance of the workpiece. Then the nanosecond laser beam assists the jet beam to further process the specified shape on the micro-texture surface, such as a high aspect ratio micro-groove; the jet nozzle ejects a high-pressure jet beam to promptly remove softened materials and debris to ensure the cleanliness and quality of the processed surface.

[0051] The beneficial effects of the present invention are:

[0052] The dual-pulse width laser-assisted water jet processing method provided in the present application forms a micro-texture on the processing surface of a workpiece made of a transparent hard and brittle material with a low absorption rate through a femtosecond laser beam, changes the microstructure of the processing surface, reduces the transmittance, and enables the energy of the nanosecond laser beam used in subsequent processing to be effectively absorbed, thereby avoiding the problem of cracking of the workpiece processing position caused by high-energy laser beam processing, and providing a basis for processing lossless high aspect ratio micro-grooves; then, a nanosecond laser beam is used to further process the micro-grooves on the micro-textured surface, and a jet beam is used to remove the laser softened material, so that the shape of the micro-grooves is more precise and the surface is smoother and flatter, thereby improving the product yield; by precisely adjusting the relative position of the femtosecond laser and the nanosecond laser, the relative position of the laser cutting head and the jet nozzle, and the angle between the jet beam and the normal of the surface to be processed, the synergistic effect of the two laser beams and the jet beam is achieved, and their respective advantages are fully utilized to avoid mutual interference, thereby ensuring the continuity and consistency of the processing process.

[0053] The dual-pulse width laser-assisted water jet processing device provided in the present application precisely controls the composite cutting component and the dual-pulse width laser component through a controller, thereby achieving efficient coordination of roughening modification and specified shape processing of the to-be-processed surface of a transparent hard and brittle material workpiece with a low absorption rate; a femtosecond laser beam is used to first perform roughening modification on the to-be-processed surface to form a micro-texture, thereby improving the light absorption performance of the workpiece, so that nanosecond laser beams can be used to assist in the subsequent processing of high aspect ratio micro-grooves, and then a high-pressure jet beam is ejected from the jet nozzle to remove the softened material, thereby obtaining high aspect ratio micro-grooves with excellent surface quality and improving the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of the steps of the dual-pulse width laser-assisted water jet processing method of the present invention;

[0055] Figure 2 This is one of the structural schematic diagrams of the dual-pulse width laser-assisted water jet processing device of the present invention;

[0056] Figure 3 This is the second structural schematic diagram of the dual-pulse width laser-assisted water jet processing device of the present invention;

[0057] Figure 4 This is the third structural schematic diagram of the dual-pulse width laser-assisted water jet processing device of the present invention.

[0058] Reference numerals:

[0059] 1. Controller; 2. Composite cutting component; 3. Dual-pulse laser component; 4. Three-axis motion platform; 5. Laser cutting head; 6. Jet nozzle; 7. Femtosecond laser beam; 8. Nanosecond laser beam; 9. Water pump; 10. Jet beam; 11. Nanosecond laser; 12. Nanosecond laser beam expander; 13. Femtosecond laser; 14. Femtosecond laser beam expander; 15. Single crystal gallium nitride workpiece. DETAILED DESCRIPTION

[0060] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0061] Common transparent hard and brittle semiconductor materials include oxide semiconductors and nitride semiconductors. They are widely used in transparent displays, solar cells, sensors and other fields because of their superior electrical and physical properties. However, the brittleness of the materials makes them prone to breakage or cracking during processing. For this problem, laser-assisted water jet processing technology is a better solution. Laser radiation is used to increase the surface temperature of the material and reduce the hardness of the material in the processing area. High-pressure water jets are then used to assist in removing the softened material to reduce cracking problems caused by the processing of hard and brittle materials.

[0062] Although the above scheme is applicable to most common transparent hard and brittle semiconductor materials, when processing transparent hard and brittle semiconductor materials with low absorption rate, due to their strong brittleness and low laser absorption rate, the existing method of using a single laser processing is still prone to edge cracking at the processing position or the workpiece cannot absorb laser energy, making it difficult to obtain high aspect ratio micro-grooves with excellent surface quality, and the product yield is low.

[0063] Based on this, the present application provides a dual-pulse width laser-assisted water jet processing method and device.

[0064] Example 1

[0065] See also Figure 2 to Figure 4 The dual-pulse width laser-assisted water jet processing device provided in this embodiment includes a controller 1, a composite cutting component 2 and a dual-pulse width laser component 3. The controller 1 is used to accurately control the equipment operation of the overall processing process. The composite cutting component 2 is used to process the processing surface to form micro-textures and perform processing of specified shapes. The dual-pulse width laser component 3 provides laser beams with different pulse widths for fine processing of the workpiece. A three-axis motion platform 4 is installed under the composite cutting component 2. The three-axis motion platform 4 is used to install the workpiece and drive the workpiece to move along a preset path. The composite cutting component 2, the dual-pulse width laser component 3 and the three-axis motion platform are all electrically connected to the controller 1.

[0066] The composite cutting assembly 2 includes a laser cutting head 5 and a jet nozzle 6. The laser cutting head 5 is provided with two, which respectively emit a femtosecond laser beam 7 and a nanosecond laser beam 8 for processing. The jet nozzle 6 is connected to a water pump 9 to spray a jet beam 10 at high pressure. The jet beam 10 removes softened materials and debris under the assistance of two laser beams with different pulse widths and wavelengths. The medium of the jet beam 10 is deionized water. Deionized water has the characteristics of high purity and low conductivity, which can effectively avoid the introduction of impurities or electrochemical corrosion during the processing process, and ensure the surface purity and quality of the finished product. The water pump 9 is preferably a constant pressure water pump 9, which can provide a stable pressure output to ensure that the pressure of the jet beam 10 is constant during the processing process, the impact force on the workpiece is uniform and consistent, and the processing stability is improved.

[0067] The dual-pulse laser assembly 3 includes a nanosecond laser 11 and a nanosecond laser beam expander 12. The nanosecond laser 11 and the nanosecond laser beam expander 12 are installed on the same vertical line with one of the laser cutting heads 5. The nanosecond laser 11 emits a nanosecond laser beam 8, and the nanosecond laser beam expander 12 re-converges the divergent laser into parallel light and transmits it to the laser cutting head 5.

[0068] The dual-pulse laser assembly 3 also includes a femtosecond laser 13 and a femtosecond laser beam expander 14. The femtosecond laser 13 and the femtosecond laser beam expander 14 are both installed on one side of the nanosecond laser 11 and the nanosecond laser beam expander 12. The femtosecond laser and the femtosecond laser beam expander are both installed on the same vertical line as the other laser cutting head. The femtosecond laser 13 emits a femtosecond laser beam 7, and the femtosecond laser beam expander 14 re-converges the divergent laser into parallel light and transmits it to the laser cutting head 5.

[0069] A transparent hard and brittle material workpiece with low absorption rate is installed on the three-axis moving platform. In this embodiment, a non-doped single-crystal gallium nitride workpiece 15 is selected. Due to its transparent characteristics, it cannot directly absorb the energy of the nanosecond laser beam 8. Therefore, the processing surface needs to be roughened and modified first.

[0070] A jet waste liquid recovery tank is provided below the three-axis motion platform 4 to collect the waste liquid generated during the processing.

[0071] The working process of the dual-pulse width laser-assisted water jet processing device provided by the present invention is as follows:

[0072] First, the three-axis motion platform 4 moves the non-doped single-crystal gallium nitride workpiece 15 to the processing position, and by adjusting the femtosecond laser beam expander 14, the femtosecond laser beam 7 emitted by the femtosecond laser 13 is transmitted to the laser cutting head 5 and then emitted to perform roughening modification on the processing surface to form a microtexture; as the workpiece moves, the microtexture moves to the processing position of the nanosecond laser beam 8 and the jet beam 10 to further process the specified shape, such as a high aspect ratio microgroove; the nanosecond laser beam 8 irradiates to increase the surface temperature of the workpiece and reduce the mechanical properties of the material, and the jet nozzle 6 sprays a high-pressure jet beam 10 to remove softened materials and debris; during the processing, the jet waste liquid recovery tank collects the waste liquid generated to keep the working environment clean.

[0073] The dual-pulse width laser-assisted water jet processing device provided in the present application precisely controls the composite cutting component 2 and the dual-pulse width laser component 3 through a controller 1, thereby realizing efficient coordination of roughening modification and designated shape processing of the to-be-processed surface of a transparent hard and brittle material workpiece with a low absorption rate; a femtosecond laser beam 7 is used to firstly perform roughening modification on the to-be-processed surface to form a micro-texture, thereby improving the light absorption performance of the workpiece, so that a nanosecond laser beam 8 can be used to assist in the subsequent processing of high aspect ratio micro-grooves, and then a high-pressure jet beam 10 is ejected from a jet nozzle 6 to remove the softened material, thereby obtaining high aspect ratio micro-grooves with excellent surface quality and improving the product yield.

[0074] Example 2

[0075] See also Figure 1 to Figure 4 This embodiment provides a dual-pulse width laser-assisted water jet processing method, using the dual-pulse width laser-assisted water jet processing device of embodiment 1, including the following steps:

[0076] S1. Processing equipment adjustment:

[0077] Adjust the laser cutting head 5 and the jet nozzle 6 to above the three-axis motion platform 4;

[0078] The laser cutting head 5 is calibrated so that the laser can focus vertically on the processing horizontal reference plane to ensure the accuracy of the starting point and direction;

[0079] Adjust the relative position of the femtosecond laser 13 and the nanosecond laser 11 so that the spot of the femtosecond laser beam 7 and the spot of the nanosecond laser beam 8 do not overlap, and the spot of the femtosecond laser beam 7 and the spot of the nanosecond laser beam 8 are both located on the preset processing starting point moving path, so that the two laser beams are connected and work together in an orderly manner during the processing;

[0080] Adjust the relative position of the laser cutting head 5 and the jet nozzle 6 so that the laser beam and the jet beam 10 are located in the same vertical plane, open the jet nozzle 6, and adjust the angle between the jet beam 10 and the normal of the surface to be processed. When the angle is 45°, the jet beam 10 can impact the surface to be processed at the best angle, effectively remove the softened material and debris generated during the processing, and reduce the damage to the surface to be processed, ensuring the surface smoothness and quality of the finished product;

[0081] Adjust the offset distance between the incident point of the jet beam 10 and the center point of the spot of the nanosecond laser beam 8. The appropriate offset distance makes the incident point of the jet beam 10 and the center point of the spot of the nanosecond laser beam 8 staggered to avoid direct overlap and mutual interference between the two, so that both the nanosecond laser beam 8 and the jet beam 10 can be processed more accurately to meet complex processing requirements;

[0082] After adjustment, the light spot of the femtosecond laser beam 7, the light spot of the nanosecond laser beam 8, and the incident point of the jet beam 10 are arranged in a straight line along the processing direction on the surface of the workpiece to be processed, ensuring that the laser beam and the jet beam 10 can accurately act on the same area of ​​the workpiece during the processing, thereby achieving the purpose of coordinated processing;

[0083] The non-doped single-crystal gallium nitride workpiece 15 is mounted on the three-axis motion platform 4, and the position of the workpiece is adjusted by the three-axis motion platform 4 so that the surface to be processed coincides with the processing horizontal reference surface.

[0084] S2. Post-focus processing:

[0085] Calibrate the laser focus, calibrate the focal plane of the femtosecond laser beam 7 to a position below the workpiece surface to be processed. The position of the focal plane of the femtosecond laser beam 7 affects the depth and width of the roughening of the workpiece surface to be processed. Shallow depth and moderate width are preferred. When the focal plane is above the workpiece surface to be processed, the laser is not focused on the workpiece surface to be processed and cannot be processed effectively. When the focal plane is at or below the workpiece surface to be processed, the further down the workpiece surface is, the larger the light spot is, the more dispersed the energy is, and the shallower and wider the micro texture is. The optimal roughening effect is obtained when the focal plane of the femtosecond laser beam 7 is below the workpiece surface to be processed and the vertical distance from the workpiece surface to be processed is 0.2 mm.

[0086] The femtosecond laser 13 is started, and the femtosecond laser beam 7 is directed to a preset processing starting point;

[0087] Calibrate the focal plane of the nanosecond laser beam 8 to coincide with the surface to be processed of the workpiece, so as to ensure that the nanosecond laser beam 8 can act on the surface to be processed with optimal energy density and focusing performance during the processing, thereby achieving accurate processing of the workpiece;

[0088] Start the nanosecond laser 11 and the water pump 9, so that the spot of the nanosecond laser beam 8 points to the processing connection point, and the jet beam 10 is impacted by high pressure from the incident point to the processing connection point, and the processing connection point is located on the preset processing starting point moving path. As the workpiece moves, the micro-texture is formed and moves to the working area of ​​the nanosecond laser beam 8 and the jet beam 10 for further finishing, forming continuous collaborative processing and improving processing efficiency;

[0089] The straight-line distance between the center point of the spot of the femtosecond laser beam 7 and the center point of the spot of the nanosecond laser beam 8 is the straight-line distance between the preset processing starting point and the processing connection point.

[0090] S3, Roughening the surface to be processed:

[0091] The workpiece processing direction is the moving direction of the three-axis motion platform 4, which moves from the side close to the spot of the femtosecond laser beam 7 to the side close to the incident point of the jet beam 10. During the movement of the workpiece, the femtosecond laser beam 7 roughens the workpiece surface to be processed to form a micro texture, and the jet beam 10 forms a flowing water layer on the surface to be processed, and the flowing water layer removes the debris and softened material on the surface of the micro texture.

[0092] The micro-textured surface is used as a processing connection surface for processing a specified shape to obtain a higher quality processing effect;

[0093] The micro-texture evaluation index includes surface roughness and transmittance. The surface roughness reflects the flatness of the micro-texture surface. The surface roughness affects the transmittance. The transmittance measures the absorption capacity of the micro-texture to the nanosecond laser beam 8. In order to ensure that the nanosecond laser beam 8 can further process the specified shape, it is necessary to judge whether the surface roughening modification requirements of the surface to be processed are met through surface roughness and transmittance.

[0094] S4. Processing specified shape:

[0095] The micro texture is formed by the femtosecond laser beam 7 and then moved to the processing position of the nanosecond laser beam 8. The nanosecond laser beam 8 further processes the micro texture surface into a specified shape, such as a high aspect ratio micro groove, and then the softened material debris is removed by high pressure impact of the jet beam 10.

[0096] In practical applications, a jet beam 10 of 1-5 MPa is used, the angle between the center line of the jet beam 10 and the normal line of the surface to be processed is in the range of 30° to 70°, the vertical distance between the focal plane of the femtosecond laser beam 7 and the surface to be processed is in the range of 0 mm to 0.4 mm, and the offset distance between the incident point of the jet beam 10 and the center point of the nanosecond laser beam 8 spot is in the range of 0 mm to 0.5 mm.

[0097] In this embodiment, deionized water is used as the medium of the jet beam 10. Deionized water has the characteristics of high purity and low conductivity, which can effectively avoid the introduction of impurities or electrochemical corrosion during the processing process, and ensure the purity and quality of the finished product surface.

[0098] The working principle of the dual-pulse width laser-assisted water jet processing method provided by the present invention is:

[0099] Transparent hard and brittle semiconductor materials are difficult to directly absorb the nanosecond laser beam 8 due to their transparent properties. Therefore, a micro-texture is first formed on the surface to be processed of the non-doped single-crystal gallium nitride workpiece 15 to change the microstructure of the workpiece surface, increase the roughness of the surface to be processed, and reduce the transmittance, so that the energy of the nanosecond laser beam 8 can be effectively absorbed by the workpiece, and then the nanosecond laser beam 8 and the jet beam 10 are used to further process high aspect ratio micro-grooves on the micro-textured surface to obtain high aspect ratio micro-grooves with excellent surface quality.

[0100] The dual-pulse width laser-assisted water jet processing method provided in the present application forms a micro-texture on the processing surface of the non-doped single-crystal gallium nitride workpiece 15 by a femtosecond laser beam 7, changes the microstructure of the processing surface, reduces the transmittance, and allows the energy of the nanosecond laser beam 8 used for subsequent processing to be effectively absorbed, thereby avoiding the problem of cracking at the processing position caused by direct processing with a high-energy laser beam 7, and providing a basis for processing lossless high aspect ratio micro-grooves; when the nanosecond laser beam 8 is used to assist in processing the micro-groove on the micro-textured surface, the nanosecond laser beam 8 irradiates to increase the surface temperature of the workpiece, reduces the mechanical properties of the material, and removes the laser softened material with the jet beam 10, so that the shape of the micro-groove is more precise and the surface is smoother and flatter, thereby improving the product yield; by precisely adjusting the relative positions of the femtosecond laser 13 and the nanosecond laser 11, the relative positions of the laser cutting head 5 and the jet nozzle 6, and the angle between the jet beam 10 and the normal of the processing surface, the synergistic effect of the two laser beams and the jet beam 10 is achieved, and their respective advantages are fully utilized to avoid mutual interference, thereby ensuring the continuity and consistency of the processing process.

[0101] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0102] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dual-pulse laser-assisted water jet processing method, characterized in that: The following steps are involved: S1, calibrating the laser focus, starting the laser and the water pump (9), directing the femtosecond laser beam (7), the nanosecond laser beam (8) and the jet beam (10) to the preset processing starting point moving path and starting processing; S2, the workpiece moves along a preset path, and a femtosecond laser beam (7) processes the surface to be processed of the workpiece to form a micro texture; S3, a jet beam (10) forms a flowing water layer on the surface to be processed, wherein the flowing water layer is used to remove debris from the micro-textured surface; S4, a nanosecond laser beam (8) processes a designated shape on the micro-textured surface, and a jet beam (10) removes softened material.

2. The dual-pulse width laser-assisted water jet machining method according to claim 1, characterized in that: The laser comprises a femtosecond laser (13) and a nanosecond laser (11); The specific steps of S1 include: Calibrate the laser focus, start the femtosecond laser (13), and point the femtosecond laser beam (7) to a preset processing starting point to start processing; Starting the nanosecond laser (11) and the water pump (9) so that the nanosecond laser beam (8) and the jet beam (10) act together on the processing connection point; The processing connection point is located on a preset processing starting point moving path.

3. The dual-pulse width laser-assisted water jet machining method according to claim 1, characterized in that: In S2, the surface to be processed of the workpiece is modified by a laser roughening method to form the micro texture, and the micro texture surface is used as a processing connection surface for processing a specified shape.

4. The dual-pulse width laser-assisted water jet machining method according to claim 1, characterized in that: In the step S1 of calibrating the laser focus, the focal plane of the femtosecond laser beam (7) is calibrated to a position below the surface of the workpiece to be processed; The focal plane of the nanosecond laser beam (8) is calibrated to coincide with the surface to be processed of the workpiece.

5. The dual-pulse width laser-assisted water jet machining method according to claim 1, characterized in that: Before the step S1 is started, the processing equipment needs to be adjusted, and the processing equipment also includes a three-axis motion platform (4), a jet nozzle (6), and a laser cutting head (5) that emits a femtosecond laser beam (7) and a nanosecond laser beam (8); The specific steps of adjusting the processing equipment include: Adjust the laser cutting head (5) and the jet nozzle (6) to above the three-axis motion platform (4); The laser cutting head (5) is calibrated so that the laser can be vertically focused on the processing horizontal reference plane; Adjusting the relative position of the femtosecond laser (13) and the nanosecond laser (11); Adjusting the relative positions of the laser cutting head (5) and the jet nozzle (6) so that the laser beam and the jet beam (10) are located in the same vertical plane; Mounting the workpiece on a three-axis motion platform (4); The position of the workpiece is adjusted by a three-axis motion platform (4) so ​​that the surface to be processed coincides with the processing horizontal reference surface.

6. The dual-pulse width laser-assisted water jet machining method according to claim 5, characterized in that: The relative position adjustment of the femtosecond laser (13) and the nanosecond laser (11) comprises adjusting the light spot of the femtosecond laser beam (7) and the light spot of the nanosecond laser beam (8) to be non-overlapping, and both the light spot of the femtosecond laser beam (7) and the light spot of the nanosecond laser beam (8) are located on a preset processing starting point moving path.

7. The dual-pulse width laser-assisted water jet machining method according to claim 5, characterized in that: The adjusting the relative position of the laser cutting head (5) and the jet nozzle (6) also includes opening the jet nozzle (6), adjusting the angle between the jet beam (10) and the normal line of the surface to be processed, and adjusting the offset distance between the incident point of the jet beam (10) and the center point of the spot of the nanosecond laser beam (8).

8. The dual-pulse width laser-assisted water jet machining method according to claim 6, characterized in that: The light spot of the femtosecond laser beam (7), the light spot of the nanosecond laser beam (8), and the incident point of the jet beam (10) are arranged in sequence in a straight line along the processing direction on the surface of the workpiece to be processed.

9. The dual-pulse width laser-assisted water jet machining method according to claim 8, characterized in that: The workpiece processing direction is the moving direction of the three-axis motion platform (4), which moves from a side close to the light spot of the femtosecond laser beam (7) to a side close to the incident point of the jet beam (10).

10. A device for a dual-pulse width laser-assisted water jet processing method, characterized in that: Used to implement the dual-pulse width laser-assisted water jet processing method described in any one of claims 1 to 9, The device comprises a controller (1), a composite cutting assembly (2) and a dual-pulse width laser assembly (3); the composite cutting assembly (2) and the dual-pulse width laser assembly (3) are used to process a surface to be processed to form a micro texture and to process a specified shape; a three-axis motion platform (4) is installed below the composite cutting assembly (2); the composite cutting assembly (2), the dual-pulse width laser assembly (3) and the three-axis motion platform are all electrically connected to the controller (1); The composite cutting assembly (2) comprises a laser cutting head (5) and a jet nozzle (6); the laser cutting head (5) is provided with two, respectively emitting a femtosecond laser beam (7) and a nanosecond laser beam (8) for processing; the jet nozzle (6) is connected to a water pump (9) to spray a jet beam (10) at high pressure; The dual-pulse width laser assembly (3) comprises a nanosecond laser (11) and a nanosecond laser beam expander (12), wherein the nanosecond laser (11) and the nanosecond laser beam expander (12) are installed on the same vertical line as one of the laser cutting heads (5), and the nanosecond laser beam expander (12) transmits the nanosecond laser beam (8) to the laser cutting head (5); The dual-pulse width laser assembly (3) further comprises a femtosecond laser (13) and a femtosecond laser beam expander (14); the femtosecond laser (13) and the femtosecond laser beam expander (14) are both installed on the same vertical line as the other laser cutting head (5); the femtosecond laser beam expander (14) transmits the femtosecond laser beam (7) to the laser cutting head (5).

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