Large-size wafer wide-area laser polishing device and polishing method

Abstract

The large-size wafer wide-area laser polishing device comprises a laser device, a collimating mirror, a middle reflecting mirror, a semi-transparent and semi-reflecting mirror, a focusing mirror, a CCD automatic focusing system, a tail end reflecting mirror, an air ejector and a machining motion platform, the collimating mirror is vertically arranged, the middle reflecting mirror and the semi-transparent and semi-reflecting mirror are parallel to each other, and the included angle between the middle reflecting mirror and the horizontal plane and the included angle between the middle reflecting mirror and the horizontal plane are 45 degrees; the tail end reflecting mirror is used for receiving and reflecting the laser beam from the focusing mirror, so that the laser beam is obliquely incident to a to-be-processed surface, and the CCD automatic focusing system is used for dynamically adjusting the angle of the tail end reflecting mirror and adjusting the focus position of the laser beam, so that the laser beam is ensured to be accurately focused at the to-be-processed position all the time; the air ejector is used for providing auxiliary gas in the machining process and blowing away slag and oxide generated during polishing. The double limitations that a traditional focus lens is short in working distance and a galvanometer is large in focal depth are broken through, the problem that the machining precision and the machining size cannot be both considered is solved, and the machining quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a large-size wafer wide-area laser polishing device and a polishing method. Background Art

[0002] Laser polishing uses the high energy density of lasers to focus the laser beam directly on the surface of parts to form a high temperature and high pressure area, causing the surface to melt instantly. At the same time, by absorbing laser light energy and changing surface tension, the melting or vaporization speed reaches one thousandth of a second. Since the changes in the surface structure caused by lasers will not affect the properties of the material itself, efficient and accurate polishing can be achieved, which is suitable for precision processing of hard and brittle materials.

[0003] When facing the polishing of large-sized wafers, the traditional laser polishing technology using a fixed focal length focusing mirror or a high-power objective lens often has limitations in terms of polishing accuracy and efficiency, and often cannot take both into account. For example, in pursuit of processing efficiency, a fixed focal length focusing mirror is used. Due to the short working distance of the traditional focusing mirror, the processing area of ​​the workpiece is limited. There are obvious limitations when adapting to workpieces of different thicknesses, different shapes and complex surface conditions. It is difficult to achieve the polishing uniformity and high-quality polishing effect of large-area workpieces, especially during the polishing process. Frequent adjustment of focal length or processing parameters is required, and even manual replacement of optical elements or adjustment of the focusing mirror position is required, which is not only time-consuming, but also easy to introduce errors, affecting the consistency and reliability of processing. If an ultra-high-power lens is used for vertical polishing, the requirements for equipment are high, the polishing speed is slow, and the improvement of processing size is also very limited. The method of using a long-focal-length lens for oblique incidence polishing generally uses a galvanometer oblique incidence to polish or remove rust from the workpiece, but due to the large focal depth of the galvanometer beam, its processing accuracy is low and the polishing accuracy is poor. Therefore, the above-mentioned processing methods often have the problem of not being able to achieve both processing accuracy and processing size, and it is difficult to meet the processing requirements of large-size, high-precision workpieces. Moreover, when the existing technology is used for large-area wafer polishing, the complexity of the optical system often leads to increased costs and maintenance difficulties. At the same time, there is also a lack of effective anti-collision mechanisms to reduce the risk of workpiece damage caused by this, as well as the accuracy of the automatic focusing mechanism and the insufficient motion response speed of the workpiece motion platform, which need to be urgently addressed. Summary of the invention

[0004] The purpose of the present invention is to overcome the limitation of processing range caused by the fixed focal length of the traditional laser focusing mirror, and the problem of insufficient efficiency of high-power objective lens vertical laser processing when processing large areas or complex shapes, and to provide a large-size wafer wide-area laser polishing device and a polishing method using the device. The laser processing device is designed by end-reflecting oblique incident laser beam, so that the trajectory algorithm of the wafer platform can match the movement of the laser beam, and through the CCD automatic focusing system and preliminary test process, high-precision and high-efficiency laser polishing of ultra-large wafers is achieved. This method meets the needs of high-precision, high-adaptability and automated processing in semiconductor industry production, and is particularly suitable for polishing large-area and ultra-large wafers.

[0005] The present invention is achieved through the following technical solutions:

[0006] A large-size wafer wide-area laser polishing device, comprising a mounting frame, a laser, a collimator, an intermediate reflector, a semi-transparent and semi-reflective mirror, a focusing mirror, a CCD automatic focusing system, an end reflector, an air jet, a first Z-axis moving module and a processing motion platform, wherein the laser, the collimator, the intermediate reflector, the semi-transparent and semi-reflective mirror, the focusing mirror, the CCD automatic focusing system, the end reflector and the air jet are all arranged on the mounting frame, and the mounting frame is arranged on the first Z-axis moving module; the laser is used to generate a vertically downward laser beam, and the collimator, the intermediate reflector, the semi-transparent and semi-reflective mirror, the focusing mirror and the end reflector are arranged on the first Z-axis moving module. The mirrors are arranged in sequence along the laser light path. The collimating mirror is arranged horizontally and is used to shape the original laser beam generated by the laser into a vertical parallel laser beam. The intermediate reflecting mirror and the semi-transparent and semi-reflecting mirror are parallel to each other and form an angle of 45 degrees with the horizontal plane. After the vertical laser beam is reflected by the intermediate reflecting mirror and the semi-transparent and semi-reflecting mirror in sequence to change the light path, it becomes a vertical beam again and reaches the focusing mirror. The focusing mirror is arranged horizontally and is used to focus the vertical laser beam from the semi-transparent and semi-reflecting mirror. The end reflecting mirror is arranged tilted and is used to receive the laser beam from the focusing mirror and reflect the laser beam so that the laser beam is obliquely incident on the surface of the wafer to be processed.

[0007] The CCD automatic focusing system includes a visual sensor, which is used to capture the image of the area to be processed on the wafer through high-resolution imaging technology. The visual sensor includes an LED light source, which is arranged directly above a semi-transparent and semi-reflective mirror. The semi-transparent and semi-reflective mirror allows the light of the LED light source to be transmitted while reflecting the laser beam, and finally reaches the surface of the wafer to be processed, providing lighting conditions for the visual sensor to shoot, so as to accurately identify the condition of the wafer surface. The CCD automatic focusing system is connected to a focusing mirror and an end reflector, and is used to dynamically adjust the angle of the end reflector and the distance between the end reflector and the focusing mirror according to the image information of the surface to be processed on the wafer, so as to adjust the focal position of the laser beam, ensure that the laser beam is always accurately focused on the position to be processed, thereby improving the polishing accuracy and adapting to wafers of different areas and thicknesses. The processing motion platform is located below the end reflector, and is used to fix the wafer to be processed and drive the wafer to move to cooperate with laser processing.

[0008] The jet nozzle of the jet is facing the area of ​​the wafer to be processed. The jet is used to provide auxiliary gas during the processing to help improve the polishing efficiency and quality. At the same time, the slag and oxides generated during polishing will be effectively blown away by the auxiliary gas to prevent the slag from re-solidifying on the polishing surface or causing damage to the wafer.

[0009] By adjusting the angle of the end reflector, the laser beam can be incident on the wafer surface at a certain angle, which helps to achieve effective distance adjustment for workpieces with different surface shapes to adapt to the polishing of large-area and ultra-large-area wafers. The role of the end reflector is not only to change the optical path, but also to control the laser energy acting on the workpiece surface, thereby improving the polishing quality. Simple adjustment to change the optical path angle cannot achieve effective polishing of the processed surface.

[0010] Furthermore, the CCD automatic focusing system also includes a processor and a control actuator, the processor is used to use an integrated image processing algorithm to process and analyze the image captured by the visual sensor, and transmit instructions to the control actuator and the first Z-axis moving module, the first Z-axis moving module drives the mounting frame to move up and down according to the instructions to adjust the distance between the laser focus and the wafer to be processed, the control actuator includes a second Z-axis moving module and a first swing module arranged on the mounting frame and connected to the end reflector, the second Z-axis moving module is used to drive the end reflector to move up and down according to the instructions, and the first swing module is used to drive the end reflector to rotate according to the instructions to adjust the position and angle of the end reflector and adjust the relative position of the laser focus.

[0011] Further, the processing motion platform includes an X-axis linear moving module, a Y-axis moving module, a second swinging module, a rotating module and a processing table, wherein the Y-axis moving module is arranged on the X-axis linear moving module, the second swinging module is arranged on the Y-axis moving module, the rotating module is arranged on the second swinging module, the processing table is arranged on the rotating module, the processing table is used to fix the wafer to be processed, the second swinging module is used to drive the processing table and the wafer to be processed thereon to tilt relative to the vertical direction, and the rotating module is used to drive the processing table and the wafer to be processed thereon to rotate around its vertical center axis. The rotation speed of the rotating module can be set to 300-600rpm, wherein the rotation speed can be changed according to a certain functional relationship, and the speed of the linear moving module can be controlled to be 10m / s.

[0012] Furthermore, the second swing module includes a swing motor, a swing plate and a swing arm, one end of the swing plate is vertically connected to the output shaft of the swing motor, and the other end is vertically connected to the swing arm; the rotation module includes a rotary motor, the rotary motor is mounted on the swing arm, the processing table is drivingly connected to the rotary motor, and the rotation axis of the processing table is perpendicular to the rotation axis of the swing motor. A vacuum suction cup is provided on the top of the processing table for fixing the wafer to be processed by vacuum adsorption.

[0013] Furthermore, the end reflector receives the laser beam emitted from the focusing mirror and accurately adjusts the reflection angle of the laser beam to achieve oblique incidence of the laser beam; the end reflector makes the incident angle of the laser beam obliquely incident on the surface of the wafer to be processed area be 15°-45°. The surface of the reflector is coated with a high reflectivity coating; the high reflectivity coating can be a multilayer dielectric film or a metal coating.

[0014] Furthermore, the jet injector further comprises an air inlet and an air jet outlet of the jet pipe, the air inlet and the air jet outlet are respectively arranged at the two ends of the jet pipe, the air inlet is used to connect the gas supply device, the air jet outlet is a contraction type conical nozzle structure, the gas injection flow rate range of the jet injector is 5-20L / min, and the auxiliary gas is oxygen, nitrogen, carbon dioxide or air. The jet injector can also prevent splashes from damaging or contaminating the lens during the laser polishing process, and keep the reflective mirror surface clean.

[0015] Furthermore, the mounting frame is used for installation and support, wrapping the internal components therein, playing a role of fixing and protecting, and protecting the internal components from the influence of the external environment. The mounting frame is provided with a clamp for firmly clamping the jet to ensure the precise positioning and stability of the jet during the laser polishing process. The jet is connected to the mounting frame through the clamp. The clamp includes a clamp body and a plurality of front-to-back hinged joints. The clamp body is connected to the mounting frame through the plurality of hinged joints. The plurality of front-to-back hinged joint structures make the clamp multi-axis, and can clamp the jet from multiple directions, thereby adjusting the installation angle of the jet on the mounting frame. The absolute value of the repeatability accuracy of the clamp is less than 0.005mm.

[0016] Furthermore, the mounting frame adopts a modular structure, and is composed of a plurality of housing modules, including a collimating module, a middle reflection module, a CCD focusing module, a focusing module and a terminal reflection module. The collimating module and the CCD focusing module are fixed above the middle reflection module, the focusing module is fixed below the middle reflection module, the terminal reflection module is arranged below the focusing module, the collimating mirror is fixed in the collimating module, the intermediate reflection mirror and the semi-transparent and semi-reflecting mirror are arranged in the middle reflection module, the focusing mirror is arranged in the focusing module, the jet is fixed outside the focusing module, and the terminal reflection mirror is arranged in the terminal reflection module, so as to facilitate the installation, replacement and maintenance of the components. The mounting frame is also provided with a heat dissipation channel to ensure that each component maintains a suitable temperature when working for a long time or operating at high power.

[0017] The mounting frame is connected to the first Z-axis moving module through the mounting plate, and the first Z-axis moving module is used to drive the mounting frame and the component (laser processing head) mounted on the mounting frame to move up and down according to the control instruction.

[0018] Furthermore, the laser is a continuous laser or a quasi-continuous laser, the pulse half-width of the laser beam it emits is 1 ms, the power range of the laser beam is 100-1000W, and the energy distribution of the continuous laser generated by the laser is Gaussian distribution.

[0019] Furthermore, the laser is connected to the collimator through a plug-in optical fiber connector, which facilitates the rapid replacement or connection of different lasers. The optical fiber connector couples the laser energy from the laser into the optical fiber, and then transmits it from the optical fiber to the polishing head, and first enters the collimator.

[0020] Furthermore, the collimator can reduce the influence range of the focused spot, make the energy more concentrated, and improve the polishing accuracy; the collimator is made of high thermal stability material, which can resist the heat generated during laser processing and keep the shape and refractive index of the lens stable. The high thermal stability material is K9 glass or quartz glass.

[0021] The focusing mirror can reduce the loss and distortion of the laser beam during transmission and focusing; the focal length range of the focusing mirror is about 25-200 mm, and the lens diameter range of the focusing mirror is 25-100 mm.

[0022] A large-size wafer wide-area laser polishing method, using the large-size wafer wide-area laser polishing device, comprises the following steps:

[0023] S1: Fix the wafer to be processed on the processing motion platform, move the processing motion platform to the processing area and position it, ensure that the jet is in place, and adjust the direction of the jet so that its jet direction is facing the wafer;

[0024] S2: Start the CCD automatic focusing system, obtain the wafer surface information, adjust the focus position by adjusting the mounting frame height, the position and angle of the end reflector, focus on the wafer surface, and adjust the focus to the highest point on the wafer surface; set the initial working parameters of the laser processing device according to the wafer material and thickness, and the initial working parameters include laser power, polishing speed and initial focal length;

[0025] S3: Perform a local polishing test on the edge of the wafer to verify the suitability of the current polishing parameters. Based on the test feedback, the built-in control software is used to further adjust the laser parameters to ensure the optimal polishing effect.

[0026] S4: Start the laser processing device, drive the laser beam to move autonomously along the preset path, and perform large-area polishing operations on the wafer. At the same time, the wafer is driven by the processing motion platform to perform linear translation, swing and rotation to achieve progressive thinning and polishing of the wafer layer by layer. During the operation, the CCD automatic focusing system adjusts the focus position in real time according to the real-time working conditions of the wafer surface by adjusting the height of the mounting frame, the position and angle of the end reflector;

[0027] S5: After polishing is completed, the polishing quality of the wafer is evaluated, such as edge roughness and polishing accuracy, the laser is turned off and the polishing mode is exited, and the wafer is unloaded and post-processed.

[0028] The beneficial effects of the present invention are as follows:

[0029] (1) The present invention provides a movable reflector at the end of the optical path so that the laser is incident obliquely on the processing surface, which can effectively widen the processing area and allow the laser beam to cover a larger area, thereby meeting the processing requirements of large workpieces or complex shapes and realizing wide-area processing. At the same time, this oblique incidence method also allows the laser energy to be more evenly distributed in a larger processing area, which can avoid deep processing during the polishing process and avoid the decrease in polishing accuracy caused by the increase in the depth of material removed by the laser beam, or even the appearance of dark cracks, thereby improving the surface polishing accuracy. By reducing the reflection and scattering of laser energy, a smoother polishing edge and higher energy utilization can be achieved, which is suitable for polishing large-area wafers. Compared with the traditional high-precision polishing process that requires the use of ultra-high-power focusing mirrors or galvanometers, it can simultaneously have the advantages of increasing the size of the processed workpiece and improving the polishing accuracy. When the traditional laser beam is polished vertically, the energy of the laser beam varies along the axial direction around the focusing point, which will cause the processing scale in the depth direction to become larger. Especially when high-precision polishing requires increased energy, the depth of the laser beam removing the material will also increase, resulting in a significant decrease in the polishing accuracy of the surface, and even the appearance of dark cracks. In addition, the ultra-high-power focusing mirror has high requirements for equipment, and the improvement of the processing area is also limited, and the processing speed will be reduced. The method of polishing by directly oblique incident processing with a laser beam to ensure concentrated removal of a single extremely small unit depth, due to the short working distance of the traditional focusing mirror, can only process workpieces of limited area during direct oblique incident processing. The galvanometer has a natural telecentric oblique incidence method, which can process large-sized workpieces, but when using a galvanometer to polish workpieces or remove rust, the galvanometer's beam focal depth is too large and the polishing accuracy is poor. Therefore, these traditional methods cannot achieve both processing size and processing accuracy.

[0030] (2) In addition, due to the presence of the end reflector, the entire laser polishing head can be higher than the workpiece surface, that is, during the processing, the laser polishing head is located above the workpiece and will not be directly facing the workpiece. This design cleverly avoids the processing head being too close to the workpiece or being at the same height as the workpiece or even lower than the workpiece, avoiding wear and damage to the focusing lens due to material splashing, while also reducing unnecessary vibration, displacement and heat effects caused by the close distance, and reducing the impact on processing accuracy and stability caused by these. Non-contact long-distance processing also means longer polishing head service life and lower maintenance costs.

[0031] (3) The CCD automatic focusing system eliminates the tedious process of manually replacing the reflector, ensuring that the laser beam is always accurately focused on the wafer surface in the best condition. Regardless of the material changes, thickness differences, or uneven or concave-convex changes on the wafer surface, the accuracy and consistency of the polishing process can be maintained, thereby significantly improving the processing accuracy and yield rate.

[0032] (4) A half-mirror is set in the laser light path to reflect the laser and change the light path. At the same time, it can provide lighting conditions for the visual sensing part of the CCD automatic focusing system. The visual sensing part does not need to be equipped with an additional light source, thereby improving the integration level of the system.

[0033] (5) The setting of the jet can provide auxiliary gas for the polishing process, reduce the occurrence of oxidation, discoloration, etc. during the processing, and improve the processing quality. On the other hand, it can effectively remove the slag and heat generated during the polishing process, prevent the slag from re-solidifying on the polishing surface or causing damage to the wafer, and prevent splashes from damaging or contaminating the lens, keeping the reflective mirror clean and improving polishing efficiency.

[0034] (6) Practice has proved that the polishing roughness of the final wafer product is less than 300nm, the height difference is less than 10μm, the polishing accuracy is high, the polishing speed of the wafer can reach 30min / wafer, and the processing speed is high.

[0035] (7) The modular design allows for flexible combination of components to meet the needs of different functions and is also conducive to the installation, replacement and maintenance of the equipment.

[0036] Therefore, the laser polishing head device of the present invention breaks through the dual limitations of the short working distance of the traditional focusing mirror and the large focal depth of the galvanometer, and solves the problem that both processing accuracy and processing size cannot be achieved at the same time. It not only realizes automation and intelligence in technology, improves production efficiency and processing quality, but also shows excellent flexibility, safety and high efficiency in practical applications, and meets the stringent requirements of modern industry for precision processing, such as the semiconductor industry's requirements for high-precision, high-efficiency and automated production. It has broad market application potential and is expected to promote industrial manufacturing to a higher level of automation and intelligence. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic structural diagram of a laser processing device according to an embodiment of the present invention.

[0038] Figure 2 It is a structural exploded view of the laser processing device according to an embodiment of the present invention.

[0039] Figure 3 It is a partial structural schematic diagram of the laser processing device according to an embodiment of the present invention.

[0040] Figure 4 Schematic diagram of the structure of the laser processing device according to an embodiment of the present invention.

[0041] Figure 5 It is a structural schematic diagram of a processing motion platform in a laser processing device according to an embodiment of the present invention.

[0042] Figure 6It is a schematic diagram of an enlarged structure of part of the processing motion platform in the laser processing device according to an embodiment of the present invention.

[0043] Figure 7 It is a schematic side view of a partial structure of a processing motion platform in a laser processing device according to an embodiment of the present invention.

[0044] Figure 8 It is a structural schematic diagram of another implementation manner of the processing motion platform in the laser processing device of an embodiment of the present invention.

[0045] Fig. 9 It is a schematic diagram of the structure of the CCD automatic focusing system and the control system in the laser processing device according to an embodiment of the present invention.

[0046] Fig.10 The figure is a flow chart of the laser processing method according to an embodiment of the present invention.

[0047] Figure numerals: 1-laser; 2-collimating mirror; 3-intermediate reflector; 4-semi-transparent and semi-reflective mirror; 5-focusing mirror; 6-end reflector; 7-mounting frame; 8-injector; 9-clamp; 10-CCD automatic focusing system; 11-power interface; 12-signal interface; 13-mounting plate; 14-laser beam; 15-wafer; 16-LED beam; 17-processing motion platform; 71-collimating module; 72-middle reflection module; 73-focusing module; 74-end reflection module; 75-CCD focusing module; 81-injection pipe; 82-air inlet; 83-injection port; 91-hinge joint; 92-clamp body; 171-X-axis linear moving module; 172-Y-axis moving module; 173-swing motor, 174-swing plate; 175-swing arm; 176-rotating motor; 177-processing table; 178-vacuum suction cup. DETAILED DESCRIPTION

[0048] The present invention proposes an innovative large-size wafer wide-area laser polishing device and polishing method, aiming to achieve laser thinning and polishing of ultra-large-size hard and brittle materials. The device overcomes the size limitations of traditional laser focusing technology. Its core innovation is to solve the problem that conventional focused laser beams cannot move over a large range due to size limitations and that lenses need to be frequently replaced in different scenarios. The device combines the advantages of laser focusing mirrors and high-speed galvanometers, adopts end reflection, and integrates CCD automatic focusing system to quickly locate the focus. By controlling key parameters such as laser power, frequency, pulse width and focus position, efficient and fine thinning and polishing of wafers can be achieved. Specifically:

[0049] A large-size wafer wide-area laser polishing device, such as Figures 1 to 4, including a mounting frame 7, a laser 1, a collimator 2, an intermediate reflector 3, a semi-transparent mirror 4, a focusing mirror 5, a CCD automatic focusing system 10, a terminal reflector 6, an air jet 8, a first Z-axis moving module (not shown in the figure) and a processing motion platform 17, wherein the laser 1, the collimator 2, the intermediate reflector 3, the semi-transparent mirror 4, the focusing mirror 5, the CCD automatic focusing system 10, the terminal reflector 6 and the air jet 8 are all arranged on the mounting frame 7, and the mounting frame 7 is arranged on the first Z-axis moving module; the laser 1 is used to generate a vertically downward laser beam 14, the collimator 2, the intermediate reflector 3, the semi-transparent mirror 4, the focusing mirror 5 and the terminal reflector The reflecting mirrors 6 are arranged in sequence along the laser light path. The collimating mirror 2 is arranged horizontally and is used to shape the original laser beam 14 generated by the laser 1 into a vertical parallel light. The intermediate reflecting mirror 3 and the semi-transparent and semi-reflecting mirror 4 are parallel to each other and form an angle of 45 degrees with the horizontal plane. After the vertical laser beam is reflected by the intermediate reflecting mirror 3 and the semi-transparent and semi-reflecting mirror 4 in sequence to change the light path, it becomes a vertical beam again and reaches the focusing mirror 5. The focusing mirror 5 is arranged horizontally and is used to focus the vertical laser beam 14 from the semi-transparent and semi-reflecting mirror 4. The end reflecting mirror 6 is arranged tilted and is used to receive the laser beam 14 from the focusing mirror 5 and reflect the laser beam 14 so that the laser beam 14 is obliquely incident on the surface of the wafer 15 to be processed.

[0050] The CCD automatic focusing system 10 includes a visual sensor, which is used to capture the image of the area to be processed on the wafer through high-resolution imaging technology. The visual sensor includes an LED light source, which is arranged directly above the semi-transparent and semi-reflective mirror 4. The LED light source generates an LED light beam 16. The semi-transparent and semi-reflective mirror allows the LED light beam 16 to be transmitted while reflecting the laser beam, and finally reaches the surface of the wafer to be processed through the end reflector 6, providing lighting conditions for the visual sensor to shoot, so as to accurately identify the condition of the wafer surface. The CCD automatic focusing system is connected to the focusing mirror 5 and the end reflector 6, and is used to dynamically adjust the angle of the end reflector 6 and the distance between the end reflector 6 and the focusing mirror 5 according to the image information of the surface to be processed on the wafer, so as to adjust the focal position of the laser beam 14, ensure that the laser beam 14 is always accurately focused on the position to be processed, thereby improving the polishing accuracy and adapting to wafers 15 of different areas and thicknesses. The processing motion platform 17 is located below the end reflector 6, and is used to fix the wafer 15 to be processed and drive the wafer 15 to move to cooperate with laser processing.

[0051] The processing motion platform 17 is connected to a driving device, which can drive the processing motion platform 17 to move, such as moving in the horizontal direction, rotating in the vertical direction while rotating, or rotating while swinging. The horizontal movement can be driven by an electric cylinder, and the swing and rotation structures can be driven by a motor. The combination of these moving modules can realize the processing of different positions of the workpiece on the processing motion platform 17. The specific combination method can refer to the existing technology and be set in combination with specific actual needs, and cooperate with the movement mode of the laser processing head. As one of the embodiments, Figures 5 to 8 The processing motion platform includes an X-axis linear moving module 171, a Y-axis moving module 172, a second swing module, a rotation module and a processing table 177. The Y-axis moving module 172 is arranged on the X-axis linear moving module 171, the second swing module is arranged on the Y-axis moving module 172, the rotation module is arranged on the second swing module, and the processing table 177 is arranged on the rotation module. The processing table 177 is used to fix the wafer to be processed, the second swing module is used to drive the processing table 177 and the wafer to be processed thereon to tilt relative to the vertical direction, and the rotation module is used to drive the processing table 177 and the wafer to be processed thereon to rotate around its vertical center axis. The second swing module and the rotation module cooperate with the obliquely incident laser beam of the end reflector to realize polishing of the surface of large-sized wafers, such as Fig. 9 The motion of the processing motion platform can be controlled by the control system. The rotation speed of the rotating module can be set to 300-600rpm, where the rotation speed can be changed according to a certain functional relationship, and the speed of the linear moving module can be controlled to 10m / s.

[0052] The second swing module includes a swing motor 173, a swing plate 174 and a swing arm 175. One end of the swing plate 174 is vertically connected to the output shaft of the swing motor 173, and the other end is vertically connected to the swing arm 175. The rotating module includes a rotating motor 176. The rotating motor 176 is installed on the swing arm 175. The processing table 177 is drivingly connected to the rotating motor 176, and the rotating axis of the processing table 177 is perpendicular to the rotating axis of the swing motor 173. A vacuum suction cup 178 is provided on the top of the processing table 177. The vacuum suction cup 178 is connected to a vacuum generating device for fixing the wafer to be processed by vacuum adsorption. The rotating motor 176 and the processing table 177 can be arranged on the swing arm 175 at the same time. The output shaft of the rotating motor 176 is parallel to the rotating axis of the processing seat (such as Figure 6 ) or vertical (such as Figure 5 , Figure 8 ), the output shaft of the rotating motor 176 and the rotating shaft of the processing table 177 can be connected by gear transmission. The swing motor 173 drives the swing plate 174 to rotate on the vertical plane, thereby driving the swing arm 175 and the rotating module to swing in the vertical direction, such as Figure 7 The rotary motor 176 drives the processing table 177 and the wafer to be processed thereon to rotate around the central axis of the processing table 177 .

[0053] The jet port 83 of the jet 8 is facing the area of ​​the wafer to be processed. The jet 8 is used to provide auxiliary gas during the processing to help improve the polishing efficiency and quality. At the same time, the slag and oxides generated during polishing will be effectively blown away by the auxiliary gas to prevent the slag from re-solidifying on the polishing surface or causing damage to the wafer 15.

[0054] The specific operations can be:

[0055] First, the wafer 15 to be processed is firmly fixed on the processing motion platform 17 by a clamp. According to the specific position and processing requirements of the wafer 15, a suitable mounting frame 7 is selected and fixed to install the laser 1, and the power interface 11 and the signal interface 12 are connected through a transmission line.

[0056] Then, according to the specific processing requirements, a suitable collimator 2, intermediate reflector 3, semi-transparent and semi-reflective mirror 4 and focusing mirror 5 are selected to ensure that the quality and focusing effect of the laser beam 14 are optimized. In the laser processing preparation stage, gas is input into the jet 8 through the air inlet 82 on the jet 8 to provide auxiliary gas for the processing process, which helps to effectively remove slag and control the heat-affected zone during the processing. After starting the laser 1, the laser beam 14 is transmitted through the optical fiber connector and enters the collimator 2 to start its shaping and focusing process. The original laser beam 14 is shaped into a nearly parallel beam in the collimator 2. After the intermediate reflector 3 and the semi-transparent and semi-reflective mirror 4 reflect and change the optical path, it is further shaped by the focusing mirror 5, thereby improving the accuracy and energy density of the laser.

[0057] Finally, guided by the end reflector 6, the laser beam 14 is incident obliquely at a certain angle to the surface of the wafer to be processed, thereby achieving efficient laser oblique incident processing. By adjusting the angle of the end reflector, the laser beam can be incident obliquely at a certain angle to the surface of the wafer, which helps to achieve effective distance adjustment for workpieces of different surface shapes to adapt to the polishing of large-area and ultra-large-area wafers. The role of the end reflector 6 is not only to change the optical path, but also to control the laser energy acting on the surface of the workpiece, thereby improving the polishing quality. However, simply adjusting the optical path angle cannot achieve effective polishing of the processed surface.

[0058] As one embodiment, the laser 1 is a continuous laser 1 or a quasi-continuous laser 1, the pulse half-width of the laser beam 14 emitted by the laser 1 is about 1ms, the power range of the laser beam 14 is 100-1000W, and the energy distribution of the continuous laser generated by the laser 1 is a Gaussian distribution. The laser 1 is connected to the collimator 2 through a quick plug-in optical fiber connector, and the plug-in optical fiber connector is convenient for quickly replacing or connecting different lasers 1. The optical fiber connector couples the laser energy from the laser 1 into the optical fiber, and then transmits it from the optical fiber to the polishing head, and first enters the collimator 2.

[0059] As one of the implementation modes, the collimator 2 can reduce the influence range of the focused light spot, make the energy more concentrated, and improve the polishing accuracy; the collimator 2 is made of high thermal stability material, which can resist the heat generated during the laser processing and keep the shape and refractive index of the lens stable. The high thermal stability material is K9 glass.

[0060] The focusing mirror 5 can reduce the loss and distortion of the laser beam 14 during the transmission and focusing process; the focal length range of the focusing mirror 5 is about 25-200 mm, and the lens diameter range of the focusing mirror 5 is 25-100 mm.

[0061] The end reflector 6 receives the laser beam 14 emitted from the focusing mirror 5, and accurately adjusts the reflection angle of the laser beam 14 to achieve oblique incidence of the laser beam 14. Therefore, the end reflector 6 is a key component for achieving oblique incidence of the laser. It not only reflects the laser beam 14, but also adjusts the incident angle of the laser beam 14 as needed to achieve efficient processing of large or complex-shaped wafers. As one embodiment, the surface of the end reflector 6 is coated with a high-reflectivity coating; the high-reflectivity coating can be a multi-layer dielectric film or a metal coating, preferably a dielectric film, which can reflect light of a specific wavelength and has good reflection ability. The end reflector 6 can make the laser obliquely incident on the surface of the wafer, and the incident angle of the laser beam 14 obliquely incident on the surface of the wafer to be processed is about 15°-45°.

[0062] As one of the implementation methods, Figure 5 The CCD automatic focusing system 10 also includes a processor and a control execution mechanism. The processor is used to process and analyze the image captured by the visual sensor using an integrated image processing algorithm, such as Fig. 9, and transmits instructions to the control actuator and the first Z-axis moving module. The first Z-axis moving module drives the mounting frame to move up and down according to the instructions to adjust the distance between the laser focus and the wafer to be processed. The control actuator includes a second Z-axis moving module and a first swing module that are arranged on the mounting frame 7 and connected to the end reflector 6. The second Z-axis moving module is used to drive the end reflector 6 to move up and down according to the instructions. The first swing module is used to drive the end reflector 6 to rotate according to the instructions to adjust the position and angle of the end reflector 6 and the relative position of the laser focus so that the laser beam 14 is always focused on the processing surface. Specifically, the CCD automatic focusing system controls the movement of the first Z-axis moving module through the control system. The first Z-axis moving module, the second Z-axis moving module and the first swing module can all adopt existing structures or forms. For example, the Z-axis moving module can be in the form of an electric cylinder, and the first swing module can be driven by a micro motor, which will not be repeated here.

[0063] As one of the implementation methods, Figure 3 The jet 8 also includes an air inlet 82 and an air jet pipe 81. The air inlet 82 and the air jet 83 are respectively arranged at the two ends of the air jet pipe 81. The air inlet 82 is used to connect the air supply device. The air jet 83 is a contraction type conical nozzle structure. The gas injection flow rate of the jet 8 is in the range of 5-20L / min. The auxiliary gas is oxygen, nitrogen, carbon dioxide or air. The jet 8 can also prevent splashes from damaging or contaminating the lens during the laser polishing process and keep the reflective mirror clean.

[0064] The mounting frame 7 wraps the internal components to fix and protect them from the external environment. The mounting frame 7 is provided with a clamp 9 for firmly clamping the air jet 8 to ensure the precise positioning and stability of the air jet 8 during the laser polishing process. The air jet 8 is connected to the mounting frame 7 through the clamp 9. Figure 3 The clamp 9 includes a clamp body 92 and a plurality of front-to-back connected articulated joints 91, the clamp body 92 is connected to the mounting frame 7 through the plurality of articulated joints 91, and the plurality of front-to-back connected articulated joints 91 structure makes the clamp 9 multi-axis, and can clamp the jet 8 from multiple directions, so as to adjust the installation angle of the jet 8 on the mounting frame 7. The absolute value of the repeatability accuracy of the clamp 9 is less than 0.005 mm.

[0065] As one of the embodiments, the mounting frame 7 adopts a modular structure, and is composed of a plurality of housing modules, including a collimating module 71, a middle reflection module 72, a CCD focusing module 75, a focusing module 73, and a terminal reflection module 74. The collimating module 71 and the CCD focusing module 75 are fixed above the middle reflection module 72, the focusing module 73 is fixed below the middle reflection module 72, the terminal reflection module 74 is arranged below the focusing module 73, the collimating mirror 2 is fixed in the collimating module 71, the intermediate reflection mirror 3 and the semi-transparent and semi-reflective mirror 4 are arranged in the middle reflection module 72, the focusing mirror 5 is arranged in the focusing module 73, the jet 8 is fixed outside the focusing module 73, and the terminal reflection mirror 6 is arranged in the terminal reflection module 74, so as to facilitate the installation, replacement and maintenance of the components. The CCD focusing module 75 is provided with a power interface 11 and a signal interface 12, which are used to connect the power supply and the control signal respectively.

[0066] The mounting frame 7 is also provided with a heat dissipation channel to ensure that each component maintains a suitable temperature when working for a long time or at high power. The mounting frame 7 is connected to the first Z-axis moving module through the mounting plate 13. The first Z-axis moving module is used to drive the mounting frame 7 and the components mounted on the mounting frame 7 to move up and down as a whole according to the control instructions to adapt to large-area processing of the wafer surface.

[0067] A wide-area laser polishing method, using the above-mentioned large-size wafer wide-area laser polishing device, such as Figure 6 , including the following steps:

[0068] S1: Fix the wafer 15 to be processed on the processing table 177, move the processing motion platform to the processing area and position it, ensure that the jet 8 is in place, and adjust the direction of the jet 8 so that its jet direction faces the wafer 15;

[0069] S2: Start the CCD automatic focusing system 10, obtain the wafer surface information, adjust the focus position by adjusting the mounting frame height, the position and angle of the end reflector, focus on the wafer surface, and adjust the focus to the highest point on the wafer surface; set the initial working parameters of the laser processing device according to the wafer material and thickness, and the initial working parameters include laser power, polishing speed and initial focal length;

[0070] S3: Perform a local polishing test on the edge of the wafer to verify the suitability of the current polishing parameters. Based on the test feedback, the built-in control software is used to further adjust the laser parameters to ensure the optimal polishing effect.

[0071] Since the present invention uses oblique laser incidence, this processing method is very sensitive to the focus position. Whether the energy of the focused beam can effectively remove the material needs to be verified. For this reason, it is necessary to first perform a small area processing operation, and then observe the processing effect by slightly moving the wafer to determine the focus position error. At the same time, since the edge of the wafer is relatively fragile, it is preferred to verify whether the incident laser beam energy is appropriate at the edge of the wafer, thereby ensuring the suitability of the polishing parameters.

[0072] S4: Start the laser processing device and drive the laser beam to move autonomously along the preset path to perform large-area polishing operations on the wafer. At the same time, the wafer is driven by the processing motion platform to perform linear translation, swing and rotation to achieve progressive thinning and polishing of the wafer layer by layer. During the operation, the CCD automatic focusing system can also adjust the focal position in real time according to the real-time working conditions of the wafer surface by adjusting the height of the mounting frame, the position and angle of the end reflector. The rotation speed of the processing motion platform can be set to 300-600rpm, where the rotation speed can be changed according to a certain functional relationship, and the speed of the linear motion module can be controlled to 10m / s.

[0073] S5: After polishing is completed, the polishing quality of the wafer is evaluated, such as edge roughness and polishing accuracy, the laser is turned off and the polishing mode is exited, and the wafer is unloaded and post-processed.

[0074] After the processing is completed, the laser 1 and the CCD automatic focusing system 10 are turned off, the clamp 9 is released, and the processed wafer is taken out and inspected. At the same time, the processing area is cleaned to keep the environment clean and the equipment intact, so as to prepare for the next processing.

[0075] In one embodiment, the above-mentioned laser polishing process is achieved by obliquely incident laser on the wafer surface in nitrogen; the laser 1 used is a continuous laser 1 that emits continuous laser. The laser parameters are: the laser pulse half-width is about 1ms, the power is about 100W, and the energy distribution of the continuous laser is Gaussian distribution; the gas injection flow rate of the jet 8 is about 10L / min; the injection angle of the jet 8 is about 30°; the angle at which the laser beam 14 is obliquely incident on the wafer surface through the reflector is about 45°, and the absolute value of the repeat positioning accuracy of the fixture 9 is about 0.005mm. Inspections have shown that the production speed can reach 30min / wafer, that is, it takes 30min for a wafer to be placed on the device and processed. The surface of the processed wafer is smooth and burr-free, the polishing roughness is less than 300nm, the height difference is less than 10μm, the polishing effect is good, and the size is standard.

[0076] The processing quality and processing efficiency of this embodiment are better than those of the following comparative examples 1 and 2. Specifically,

[0077] Comparative Example 1

[0078] Compared with the above embodiment, the main difference of Comparative Example 1 is that no end reflector is used, and only the conventional laser is incident vertically on the wafer surface, while other processing parameters remain unchanged. Although this simplification in design may be sufficient in some cases, it shows its limitations in many aspects.

[0079] First, using only vertical laser incident processing limits the direction of the laser beam, which can only act on the wafer surface in the vertical direction. This limitation makes it difficult to meet the processing needs of large or complex-shaped wafers, resulting in reduced processing efficiency. Due to the lack of oblique incidence capability, the laser beam cannot flexibly adapt to different parts of the wafer, especially in applications that require multi-angle or multi-directional processing.

[0080] Secondly, without the assistance of a reflector, the operator may need to frequently make manual adjustments to change the position and angle of the laser beam, which not only increases the complexity of the operation, but may also introduce additional errors due to manual adjustments, affecting processing accuracy and repeatability.

[0081] In addition, the vertical incidence method has poor adaptability to the irregularities of the wafer surface. When processing wafers with uneven or concave and convex surfaces, vertical incidence may not be able to effectively cope with these changes, resulting in reduced processing quality or even failure to complete the processing task.

[0082] In summary, although the comparative example 1 is similar to the embodiment in some basic aspects, it is not equipped with an end reflector, which significantly limits its application scope and processing capabilities. In contrast, the embodiment of the present invention provides a more efficient, flexible and adaptable laser polishing solution by integrating automatic zoom and end reflector technology, which can meet the diverse industrial processing needs.

[0083] Comparative Example 2

[0084] Compared with the above embodiment, the main difference of comparative example 2 is that no air jet is provided, and other processing parameters are kept consistent with the embodiment. This omission in configuration may cause a series of problems during the laser polishing process.

[0085] First, the lack of an air jet means that slag and oxides cannot be effectively removed during the laser polishing process. These residues may not only reduce the polishing quality, but also contaminate the end mirror, resulting in increased equipment maintenance requirements and processing interruptions.

[0086] Secondly, the lack of auxiliary gas may expand the heat affected zone of the material. This expanded thermal effect will have an adverse effect on the microstructure and mechanical properties of the material, especially in the processing of heat-sensitive materials, which may lead to the degradation of material performance.

[0087] In addition, the auxiliary gas also plays a role in increasing the material removal rate in laser processing, which helps to speed up the polishing speed. The device without an air jet reduces the processing speed due to the lack of this acceleration mechanism, which in turn affects the overall production efficiency.

[0088] In summary, although the comparative example may still work in some simple applications without the air jet, it shows obvious limitations in terms of processing quality, equipment maintenance, material property protection and production efficiency. In contrast, the air jet integrated in the embodiment not only optimizes the polishing process, but also improves the flexibility and efficiency of the processing, showing a more comprehensive industrial application potential.

[0089] The above detailed description is a specific description of a feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the patent scope of this case.

Claims

1. A large-size wafer wide-area laser polishing device, characterized in that: The invention comprises a mounting frame, a laser, a collimator, an intermediate reflector, a semi-transparent and semi-reflector, a focusing mirror, a CCD automatic focusing system, a terminal reflector, an air jet, a first Z-axis moving module and a processing motion platform, wherein the laser, the collimator, the intermediate reflector, the semi-transparent and semi-reflector, the focusing mirror, the CCD automatic focusing system, the terminal reflector and the air jet are all arranged on the mounting frame, and the mounting frame is arranged on the first Z-axis moving module; the laser is used to generate a vertically downward laser beam, and the collimator, the intermediate reflector, the semi-transparent and semi-reflector, the focusing mirror and the terminal reflector are arranged on the first Z-axis moving module. They are arranged in sequence along the laser optical path. The collimator is arranged horizontally to shape the original laser beam generated by the laser into a vertical parallel laser beam. The intermediate reflector and the semi-transparent and semi-reflective mirror are parallel to each other and form an angle of 45 degrees with the horizontal plane. The vertical laser beam is reflected by the intermediate reflector and the semi-transparent and semi-reflective mirror in sequence and reaches the focusing mirror. The focusing mirror is arranged horizontally to focus the vertical laser beam from the semi-transparent and semi-reflective mirror. The terminal reflector is arranged tilted to receive the laser beam from the focusing mirror and reflect the laser beam so that the laser beam is obliquely incident on the surface of the wafer to be processed area. The CCD automatic focusing system includes a visual sensor, which is used to capture the image of the area to be processed on the wafer through high-resolution imaging technology. The visual sensor includes an LED light source, which is arranged directly above a semi-transparent and semi-reflective mirror. The semi-transparent and semi-reflective mirror reflects the laser beam while allowing the light of the LED light source to be transmitted and finally reach the surface of the wafer to be processed, providing lighting conditions for the shooting of the visual sensor. The CCD automatic focusing system is connected to a focusing mirror and an end reflector, and is used to dynamically adjust the angle of the end reflector and the distance between the end reflector and the focusing mirror according to the captured image information of the area to be processed on the wafer, so as to adjust the focal position of the laser beam and ensure that the laser beam is focused at the position to be processed to adapt to wafers of different areas and thicknesses; the jet port of the jet is directly facing the area to be processed of the wafer, and the jet is used to provide auxiliary gas during the processing and blow away the residues generated by the processing; the processing motion platform is located below the end reflector, and is used to fix the wafer to be processed and drive the wafer to move to cooperate with laser processing.

2. A large-size wafer wide-area laser polishing device according to claim 1, characterized in that: The CCD automatic focusing system also includes a processor and a control actuator. The processor is used to use an integrated image processing algorithm to process and analyze the image captured by the visual sensor, and transmit instructions to the control actuator and the first Z-axis moving module. The first Z-axis moving module drives the mounting frame to move up and down according to the instructions to adjust the distance between the laser focus and the wafer to be processed. The control actuator includes a second Z-axis moving module and a first swing module arranged on the mounting frame and connected to the end reflector. The second Z-axis moving module is used to drive the end reflector to move up and down according to the instructions. The first swing module is used to drive the end reflector to rotate according to the instructions to adjust the position and angle of the end reflector and adjust the relative position of the laser focus.

3. The large-size wafer wide-area laser polishing device according to claim 1, characterized in that: The processing motion platform includes an X-axis linear moving module, a Y-axis moving module, a second swing module, a rotating module and a processing table, the Y-axis moving module is arranged on the X-axis linear moving module, the second swing module is arranged on the Y-axis moving module, the rotating module is arranged on the second swing module, and the processing table is arranged on the rotating module, the processing table is used to fix the wafer to be processed, the second swing module is used to drive the processing table and the wafer to be processed thereon to tilt relative to the vertical direction, and the rotating module is used to drive the processing table and the wafer to be processed thereon to rotate around its vertical center axis.

4. A large-size wafer wide-area laser polishing device according to claim 3, characterized in that: The second swing module includes a swing motor, a swing plate and a swing arm, one end of the swing plate is vertically connected to the output shaft of the swing motor, and the other end is vertically connected to the swing arm; the rotation module includes a rotating motor, which is installed on the swing arm, the processing table is drive-connected to the rotating motor, and the rotating axis of the processing table is perpendicular to the rotating axis of the swing motor; a vacuum suction cup is provided on the top of the processing table for fixing the wafer to be processed by vacuum adsorption.

5. The large-size wafer wide-area laser polishing device according to claim 1, characterized in that: The surface of the end reflector is coated with a high reflectivity coating, which is a multilayer dielectric film or a metal coating; the end reflector makes the laser beam obliquely incident on the surface of the wafer to be processed at an incident angle of 15°-45°.

6. The large-size wafer wide-area laser polishing device according to claim 1, characterized in that: The jet injector further comprises an air inlet and an injection nozzle of an injection pipe, wherein the air inlet and the injection nozzle are respectively arranged at two ends of the injection pipe, the air inlet is used to connect to the gas supply equipment, the injection nozzle is a contracting conical nozzle structure, the gas injection flow rate range of the jet injector is 5-20L / min, and the auxiliary gas is oxygen, nitrogen, or air.

7. The large-size wafer wide-area laser polishing device according to claim 1, characterized in that: A clamp is provided on the mounting frame, and the jet is connected to the mounting frame via the clamp; the clamp includes a clamp body and a plurality of front-to-back hinged joints, and the clamp body is connected to the mounting frame via the plurality of hinged joints, and the plurality of front-to-back hinged joint structures make the clamp multi-axis, thereby adjusting the mounting angle of the jet on the mounting frame, and the absolute value of the repeatability positioning accuracy of the clamp is less than 0.005 mm.

8. The large-size wafer wide-area laser polishing device according to claim 1, characterized in that: The mounting frame adopts a modular structure and is composed of a plurality of housing modules. The plurality of housing modules include a collimating module, a middle reflection module, a CCD focusing module, a focusing module and a terminal reflection module. The collimating module and the CCD focusing module are fixed above the middle reflection module, the focusing module is fixed below the middle reflection module, the terminal reflection module is arranged below the focusing module, the collimating mirror is fixed in the collimating module, the intermediate reflection mirror and the semi-transparent and semi-reflecting mirror are placed in the middle reflection module, the focusing mirror is placed in the focusing module, the air jet is fixed outside the focusing module, and the terminal reflection mirror is arranged in the terminal reflection module; the mounting frame is connected to the first Z-axis moving module through the mounting plate, and the first Z-axis moving module is used to drive the mounting frame and the components mounted on the mounting frame to move up and down according to the control instructions. .

9. The large-size wafer wide-area laser polishing device according to claim 1, characterized in that: The material of the collimator is K9 glass or quartz glass; the focal length range of the focusing mirror is about 25-200mm, and the lens diameter range of the focusing mirror is 25-100mm; the laser is a continuous laser or a pulsed laser, the pulse half-width of the laser beam emitted by it is 1ms, the power range of the laser beam is 100-3000W, and the energy distribution of the continuous laser generated by the laser is a Gaussian distribution; the laser is connected to the collimator through a plug-in optical fiber connector, and the laser beam emitted by the laser enters the collimator through the optical fiber connector.

10. A large-size wafer wide-area laser polishing method, using the large-size wafer wide-area laser polishing device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Fix the wafer to be processed on the processing motion platform, move the processing motion platform to the processing area and position it, ensure that the jet is in place, and adjust the direction of the jet so that its jet direction faces the wafer; S2: Start the CCD automatic focusing system, obtain the wafer surface information, adjust the focus position by adjusting the mounting frame height, the position and angle of the end reflector, focus on the wafer surface, and adjust the focus to the highest point on the wafer surface; set the initial working parameters of the laser processing device according to the wafer material and thickness, and the initial working parameters include laser power, polishing speed and initial focal length; S3: Perform a local polishing test on the edge of the wafer to verify the suitability of the current polishing parameters. Based on the test feedback, the built-in control software is used to further adjust the laser parameters to ensure the optimal polishing effect. S4: Start the laser processing device, drive the laser beam to move autonomously along the preset path, and perform large-area polishing operations on the wafer. At the same time, the wafer is driven by the processing motion platform to perform linear translation, swing and rotation to achieve progressive thinning and polishing of the wafer layer by layer. During the operation, the CCD automatic focusing system adjusts the focus position in real time according to the real-time working conditions of the wafer surface by adjusting the height of the mounting frame, the position and angle of the end reflector; S5: After polishing is completed, the polishing quality of the wafer is evaluated, the laser is turned off and the polishing mode is exited, and the wafer is unloaded and post-processed.

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