Apparatus and method for array rheo-polishing anisotropic materials

Abstract

The application discloses a device and method for array rheological polishing of anisotropic materials, and realizes efficient one-way polishing of a specific crystal direction according to workpiece properties, and completely solves the problems of disorder, low efficiency and uncontrollable removal in traditional processes. The device comprises a mounting frame, a polishing pool is arranged in the middle of the mounting frame, a workpiece clamp module is arranged in the polishing pool, and is used for fixing a wafer workpiece and performing 90-degree rotary positioning; a polishing tool module is arranged on the workpiece clamp module in cooperation, the polishing tool module is movably arranged in the mounting frame through a moving module, reciprocating motion of the polishing tool module above the wafer workpiece is used for maintaining single-direction non-contact shear thickening polishing of the surface of the wafer workpiece; and the polishing pool, a peristaltic pump and a stirrer arranged in the mounting frame form a polishing liquid circulating mechanism, which is used for preparing, uniformly stirring and conveying shear thickening polishing liquid to the polishing tool module, and simultaneously recycling the outflow polishing liquid to form a closed loop circulation.

Description

Technical Field

[0001] This invention belongs to the field of ultra-precision machining technology, specifically relating to an apparatus and method for array rheological polishing of anisotropic materials. Background Technology

[0002] With the rapid development of science and technology, the performance requirements for key core devices in high-precision fields such as advanced optical components, semiconductors, and microelectronics are becoming increasingly stringent. As the cornerstone of these high-end devices, single-crystal materials such as silicon carbide (SiC), gallium nitride (GaN), silicon (Si), and sapphire are widely used due to their excellent physical, mechanical, and optoelectronic properties. However, these materials typically exhibit extremely high hardness, significant brittleness, and strong anisotropy. The atomic density, hardness, and fracture toughness vary greatly in different crystal orientations, such as

[100] and

[010] . Therefore, there is an urgent need to develop specialized ultra-precision machining equipment and methods capable of achieving extremely low surface roughness and no subsurface damage for these workpieces with unique physical properties.

[0003] For ultra-precision polishing of the surfaces of the aforementioned anisotropic single-crystal materials, the main processing methods currently used in industry include traditional mechanical grinding, chemical mechanical polishing (CMP), and the shear-thickening fluid polishing (STP) that has emerged in recent years. While these methods can achieve surface smoothing to some extent, considering the anisotropic characteristics of the material, the requirements for nanoscale surface quality, and factors such as production efficiency and stability, they still have the following significant limitations:

[0004] First, traditional grinding and CMP processes often employ a dual-rotation or complex cross-motion trajectory between the polishing disc and the workpiece. This multi-directional random motion completely ignores the anisotropic characteristics of single-crystal materials, causing the abrasive grains to force cutting along the "difficult-to-machine crystal orientation" of the material. This easily leads to microscopic cleavage, lattice damage, and cross-scratches, making it difficult to overcome the limit of subsurface damage.

[0005] Secondly, although existing STP technology effectively improves surface quality by utilizing the "hydrodynamic cluster" phase change effect of non-Newtonian fluids at high shear rates (forming flexible bonded abrasives), most of them adopt a single-wheel polishing structure, resulting in extremely low single-point material removal efficiency, which is difficult to meet the needs of industrial mass production.

[0006] Furthermore, the stability of the flow field within the polishing gap is crucial for stimulating the shear thickening effect. However, existing polishing fluid supply methods are mostly simple dripping or spraying, which cannot meet the immersion-based stable supply required for shear thickening fluids in high-speed continuous polishing, and are prone to fluid film rupture and local dry friction phenomena.

[0007] Finally, the workpiece fixtures in existing equipment are mostly simple vacuum adsorption mechanisms, lacking the integrated function of high-precision crystal orientation addressing and polishing direction rotation; and the entire processing lacks the guidance of a mathematical analytical model for material removal (MRR) that deeply couples the "unique polishing device" and "non-Newtonian fluid characteristics", making the processing a "black box" and difficult to achieve truly controllable quantitative removal.

[0008] Based on the above situation, and taking into account the anisotropic characteristics of single-crystal materials, and combining the advantages of high quality and no subsurface damage in shear-thickening polishing, the applicant proposes an apparatus and method for array rheological polishing of anisotropic materials based on shear-thickening fluid. Summary of the Invention

[0009] To overcome the shortcomings of existing technologies, the present invention aims to provide an apparatus and method for array rheological polishing of anisotropic materials. This method can not only achieve efficient unidirectional polishing of specific crystal orientations strictly according to the workpiece properties, but also completely solve the problems of messy orientations, low efficiency and uncontrollable removal in traditional processes through unique fixtures, liquid supply modules and unique MRR material removal functions. This greatly reduces the processing cost of ultra-precision single crystal parts and stably outputs nanoscale surface quality.

[0010] To achieve the above objectives, the present invention may adopt the following specific technical solutions:

[0011] On one hand, the present invention provides an apparatus for array rheological polishing of anisotropic materials, including a mounting frame, a polishing pool in the middle of the mounting frame, a workpiece clamping module in the polishing pool for fixing a wafer workpiece and rotating it 90 degrees for positioning; a polishing tool module is fitted on the workpiece clamping module, the polishing tool module is movably mounted in the mounting frame via a moving module, the polishing tool module reciprocates above the wafer workpiece for non-contact shear-thickening polishing of the wafer workpiece surface in a single direction; and the polishing pool, together with a peristaltic pump and a stirrer disposed in the mounting frame, constitute a polishing fluid circulation mechanism for preparing, stirring evenly and delivering shear-thickening polishing fluid to the polishing tool module, while simultaneously recovering the outflowing polishing fluid to form a closed-loop circulation.

[0012] Furthermore, the polishing tool module includes a rectangular box with an open bottom. A forward rotation component and a reverse rotation component are arranged side-by-side within the rectangular box. The forward rotation component includes a forward rotation servo motor and two forward rotation polishing wheels driven by the servo motor. The reverse rotation component includes a reverse rotation servo motor and two reverse rotation polishing wheels driven by the servo motor. The two forward rotation polishing wheels and the two reverse rotation polishing wheels are arranged parallel to each other along the length of the rectangular box. The forward rotation polishing wheels and the reverse rotation polishing wheels have identical structures, and polishing fluid nozzles are provided between the two forward rotation polishing wheels, between the two reverse rotation polishing wheels, and between the forward rotation component and the reverse rotation component. The forward rotation servo motor drives the two forward rotation polishing wheels to rotate clockwise via a synchronous pulley set, thereby driving the polishing fluid to polish the surface of the wafer workpiece and discharging the polishing fluid outwards. The reverse rotation servo motor drives the two reverse rotation polishing wheels to rotate counterclockwise via another synchronous pulley set, discharging the polishing fluid outwards. The surface of each polishing wheel can be machined with guide grooves according to the specific viscosity of the polishing fluid to enhance the hydrodynamic pressure effect.

[0013] Furthermore, a row of elongated holes is opened at the bottom of the polishing liquid nozzle, and the length of the polishing liquid nozzle is similar to the axial length of the forward-rotating polishing wheel and the reverse-rotating polishing wheel; a polishing liquid transfer box is provided on the rectangular box, and the top of the polishing liquid transfer box is provided with a polishing liquid inlet, and one side is connected to three liquid outlet pipes, which are respectively connected to the three polishing liquid nozzles, to buffer the pumped polishing liquid and evenly distribute the polishing liquid into the three polishing liquid nozzles.

[0014] Furthermore, the rectangular box is equipped with laser displacement sensors on both outer walls along its length to measure in real time the distance between the bottom of the forward and reverse polishing wheels and the surface of the wafer workpiece.

[0015] Furthermore, the workpiece clamping module includes a circular suction cup assembly. Polishing plates are positioned on both sides of the suction cup assembly to collect overflowing polishing fluid and provide a transition zone for the polishing tool module. A ventilation shaft is located below the center of the suction cup assembly. The bottom end of the ventilation shaft is mounted on a rotary cylinder. When the rotary cylinder is ventilated, it drives the ventilation shaft and the suction cup assembly above it to rotate 90 degrees. This structure enables rapid switching between the

[100] and

[010] crystal orientations of the wafer workpiece during polishing without disassembling or re-clamping the workpiece.

[0016] Furthermore, the suction cup assembly includes a suction cup plate and a suction cup cover plate. A plurality of suction cups are evenly spaced on the suction cup plate, and the suction cup cover plate covers the suction cup plate. The suction cup cover plate is provided with through holes for the suction cups to pass through. The height of the suction cups in their natural state is higher than the upper surface of the suction cup cover plate.

[0017] The suction cup cover plate has a recessed circular shallow groove on its surface for positioning a circular wafer workpiece, and a V-shaped groove for positioning the crystal orientation of the wafer workpiece.

[0018] Furthermore, the upper surface of the suction cup plate is provided with a suction cup threaded hole for mounting the suction cup, and the suction cup plate is internally machined with interconnected ventilation channels. All ventilation channels eventually converge below the center of the suction cup plate and are connected to the ventilation shaft. When an external vacuum source evacuates through the ventilation shaft, the suction cup picks up the wafer workpiece and deforms downward due to the negative pressure, so that the bottom surface of the wafer workpiece is tightly adhered to and pulled down to the surface of the rigid suction cup cover plate.

[0019] Furthermore, the moving module includes a slide rail assembly and a lifting assembly. The slide rail assembly includes a horizontal slide rail disposed on the upper part of the inner wall of one side of the mounting frame. The lifting assembly moves along the horizontal slide rail in the X direction via a slider. The lifting assembly includes a U-shaped frame and a lifting platform. The U-shaped frame cooperates with the horizontal slide rail via a slider. The lifting platform is disposed within the U-shaped frame and moves up and down between the upper and lower walls of the U-shaped frame in cooperation with a lead screw and a motor. The polishing tool module is suspended by mounting plates disposed on both sides of the lifting platform.

[0020] On the other hand, the present invention provides a polishing method for anisotropic materials using array rheological polishing, which is implemented using the aforementioned apparatus for array rheological polishing of anisotropic materials. It utilizes a material removal function coupled with shear-thickening fluid dynamics and abrasive contact mechanics for quantitative processing, specifically including the following steps:

[0021] Step S1: Use a white light interferometer to measure the original surface roughness and flatness of the wafer workpiece, determine the target surface shape to be achieved, and calculate the absolute material removal depth to be processed. The wafer workpiece is then placed into the workpiece clamping module and vacuum-clamped.

[0022] Step S2: Prepare the shear-thickening polishing slurry. Mix 35wt%-40wt% shear thickener, 20wt%-30wt% deionized water-based liquid, 10wt% dispersant, and 30wt%-35wt% abrasive particles uniformly according to their mass percentages. Measure the shear stress-shear rate data of the polishing slurry using a rheometer. Add polishing slurry to the polishing slurry circulation mechanism and start it;

[0023] Step S3: After setting the process parameters, start the first polishing process of the

[100] crystal orientation of the wafer workpiece. The set process parameters include the polishing wheel speed. The machining clearance between the polishing wheel and the workpiece The moving speed of the polishing tool ;

[0024] Step S4: Calculate the material removal depth of a single polishing stroke. ,according to The number of times the polishing tool reciprocates, N, is obtained.

[0025] Step S5: The fixture module rotates the workpiece 90 degrees to perform the second polishing process of the

[010] crystal orientation of the wafer workpiece.

[0026] Furthermore, in step S4, the material removal depth The calculation formula is as follows:

[0027] ,

[0028] In the formula, , The material-chemical coupling constant, This is the dynamic pressure shape factor. The abrasive grain mass concentration, The average particle size of the abrasive grains. This is the consistency coefficient of the polishing slurry. The radius of the polishing wheel, The hardness of the workpiece material. The linear velocity of the polishing wheel's rotation. For tool feed rate, This is the polishing gap.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) Achieving crystal orientation-selective unidirectional nanoscale polishing: For anisotropic single crystal materials, this method can perform high-precision unidirectional polishing strictly according to the crystallographic characteristics of the material (such as

[100] and

[010] crystal orientations). This effectively avoids the material anisotropic removal differences and surface scratch cross-interference caused by traditional multi-directional / rotational polishing, thereby obtaining ultra-high polished surface quality with extremely low roughness and no subsurface damage.

[0031] (2) Synergistic effect of array polishing and immersion supply: The present invention adopts an innovative array polishing tool module, which expands the effective processing area by multiple times while maintaining the unidirectional physical shear characteristics, greatly improving the polishing efficiency; with the special polishing fluid supply pipeline design, the immersion, uniform and stable supply of shear thickening polishing fluid (STF) is realized, ensuring the consistency of fluid dynamic pressure and rheological phase change process in the processing area.

[0032] (3) Highly integrated clamping and orientation positioning mechanism: The workpiece fixture module integrates the flexible clamping of the vacuum chuck and the precise rotation function of the polishing direction; this integrated design enables the workpiece to quickly switch between different crystal orientation processing trajectories in a single clamping, avoiding the positioning error caused by secondary clamping, and significantly improving the process continuity and processing accuracy.

[0033] (4) High deterministic prediction and control of material removal: By deeply integrating the polishing method characteristics of this device with the non-Newtonian rheological properties of shear thickening fluid, a unique mathematical analytical model of material removal rate (MRR) is constructed. This function not only explains the processing process from a mechanistic perspective, but also provides rigorous theoretical and algorithmic support for the controllable and quantitative material removal of wafers, ensuring the stable output of nanoscale surface accuracy. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0035] Figure 2 This is a partial structural schematic diagram of the device of the present invention;

[0036] Figure 3 This is a schematic diagram of the polishing tool module structure of the present invention;

[0037] Figure 4 This is a bottom view of the polishing tool module of the present invention;

[0038] Figure 5 This is a schematic diagram of the workpiece clamping module of the present invention;

[0039] Figure 6 This is a schematic diagram of the cross-sectional structure of the air passage of the suction cup suction plate of the workpiece clamping module of the present invention;

[0040] Figure 7 This is a schematic diagram of the structure of the mobile module of the present invention;

[0041] Figure 8 This is a diagram showing the surface morphology and roughness of random point 1 after array rheological polishing in a specific embodiment of the present invention;

[0042] Figure 9 This is a diagram showing the surface morphology and roughness obtained at random point 2 after array rheological polishing in a specific embodiment of the present invention.

[0043] In the diagram: 1-Polishing tool module, 10-Forward rotation component, 101-Forward rotation servo motor, 102-Forward rotation polishing wheel, 11-Reverse rotation component, 111-Reverse rotation servo motor, 112-Reverse rotation polishing wheel, 12-Polishing slurry nozzle, 13-Synchronous belt pulley set, 131-Drive pulley, 132-Driven pulley, 133-Synchronous belt, 14-Polishing slurry transfer box, 15-Laser displacement sensor, 16-Rectangular box, 17-Discharge pipe, 2-Wafer workpiece, 3-Workpiece clamp The module includes: 31-suction cup assembly, 311-suction cup suction plate, 312-suction cup cover plate, 313-suction cup, 32-polishing plate, 33-ventilation shaft, 34-rotary cylinder, 4-polishing tank, 5-peristaltic pump, 6-stirrer, 7-mounting frame, 8-moving module, 81-slide rail assembly, 811-horizontal slide rail, 812-slider, 82-lifting assembly, 821-U-shaped frame, 822-lifting platform, 823-lead screw, 824-motor, and 825-mounting plate. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] Example 1

[0046] like Figures 1-7 As shown, this embodiment provides an apparatus for array rheological polishing of anisotropic materials, including a mounting frame 7, a polishing pool 4 in the middle of the mounting frame 7, a workpiece clamping module 3 in the polishing pool 4 for fixing the wafer workpiece 2 and rotating it 90 degrees for positioning; a polishing tool module 1 is fitted on the workpiece clamping module 3, the polishing tool module 1 is movably mounted in the mounting frame 7 via a moving module 8, and the polishing tool module 1 reciprocates above the wafer workpiece 2 to maintain non-contact shear thickening polishing of the surface of the wafer workpiece 2 in a single direction; and the polishing pool 4, together with the peristaltic pump 5 and the stirrer 6 disposed in the mounting frame 7, constitute a polishing liquid circulation mechanism to prepare, stir evenly and deliver shear thickening polishing liquid to the polishing tool module 1, while recovering the outflowing polishing liquid to form a closed loop circulation.

[0047] Continue reading Figure 3 and Figure 4It is understood that the polishing tool module 1 includes a rectangular box 16 with an open bottom. A forward rotation component 10 and a reverse rotation component 11 are arranged side-by-side inside the rectangular box 16. The forward rotation component 10 includes a forward rotation servo motor 101 and two forward rotation polishing wheels 102 driven by the forward rotation servo motor 101. The reverse rotation component 11 includes a reverse rotation servo motor 111 and two reverse rotation polishing wheels 112 driven by the reverse rotation servo motor 111. The two forward rotation polishing wheels 102 and the two reverse rotation polishing wheels 112 are arranged parallel to each other along the length of the rectangular box 16. The forward rotation polishing wheels 102 and the reverse rotation polishing wheels 112 have the same structure. To achieve immersion supply of the shear-thickening polishing fluid, three polishing fluid nozzles 12 are provided, respectively located between the two forward rotation polishing wheels 102, between the two reverse rotation polishing wheels 112, and between the forward rotation component 10 and the reverse rotation component 11. A forward-rotating servo motor 101 drives two forward-rotating polishing wheels 102 to rotate clockwise via a synchronous pulley set 13, thereby driving the polishing slurry to polish the surface of the wafer workpiece 2 and discharging the polishing slurry outwards. A reverse-rotating servo motor 111 drives two reverse-rotating polishing wheels 112 to rotate counterclockwise via another synchronous pulley set 13, discharging the polishing slurry outwards. The surface of each polishing wheel can be machined with guide grooves according to the specific viscosity of the polishing slurry to enhance the hydrodynamic pressure effect. In this embodiment, the synchronous pulley set 13 includes a driving pulley 131 sleeved on the drive shaft of the forward-rotating servo motor 101 / reverse-rotating servo motor 111 and driven pulleys 132 sleeved on the ends of the forward-rotating polishing wheels 102 / reverse-rotating polishing wheels 112. The driving pulley 131 and driven pulley 132 are connected by a synchronous belt 133.

[0048] The polishing slurry nozzle 12 has a row of elongated holes at its bottom. The length of the polishing slurry nozzle 12 is similar to the axial length of the forward-rotating polishing wheel 102 and the reverse-rotating polishing wheel 112. A polishing slurry transfer box 14 is provided on the rectangular box 16. The top of the polishing slurry transfer box 14 is provided with a polishing slurry inlet, and one side is connected to three outlet pipes 17, which are respectively connected to the three polishing slurry nozzles 12. This is used to buffer the pumped polishing slurry and distribute the polishing slurry evenly into the three polishing slurry nozzles 12, ensuring that the gaps between the polishing wheels are always filled with polishing slurry and avoiding dry rotation.

[0049] Laser displacement sensors 15 are provided on the outer walls of both sides of the rectangular box 16 along its length to measure in real time the distance between the bottom of the forward-rotating polishing wheel 102 and the reverse-rotating polishing wheel 112 and the surface of the wafer workpiece 2. In this embodiment, four laser displacement sensors 15 are symmetrically arranged on both sides of the rectangular box 16. The moving module 8 can also make fine adjustments based on the real-time feedback data to strictly ensure the constant processing gap.

[0050] Continue reading Figure 5 and Figure 6It is known that the workpiece clamping module 3 includes a circular suction cup assembly 31, with polishing plates 32 on both sides of the suction cup assembly 31 to receive overflowing polishing liquid and provide a transition overtravel area for the polishing tool module 1; a ventilation shaft 33 is provided below the middle of the suction cup assembly 31, and the bottom end of the ventilation shaft 33 is mounted on a rotary cylinder 34. After the rotary cylinder 34 is ventilated, it can drive the ventilation shaft 33 and the suction cup assembly 31 above it to rotate 90 degrees. This structure can realize the rapid switching of the wafer workpiece 2 between the

[100] crystal orientation and the

[010] crystal orientation during polishing without disassembling or re-clamping the workpiece.

[0051] The suction cup assembly 31 includes a suction cup plate 311 and a suction cup cover plate 312. A plurality of suction cups 313 are evenly spaced on the suction cup plate 311. The suction cup cover plate 312 covers the suction cup plate 311 and has through holes for the suction cups 313 to pass through. The height of the suction cups 313 in their natural state is higher than the upper surface of the suction cup cover plate 312. The surface of the suction cup cover plate 312 is machined with a recessed circular shallow groove for positioning a circular wafer workpiece 2, and also has a V-shaped groove for positioning the crystal orientation of the wafer workpiece 2.

[0052] In this embodiment, there are 12 suction cups 313, evenly installed on the suction cup plate 311. The upper surface of the suction cup plate 311 has 12 suction cup threaded holes 3111 for mounting the suction cups 313. The suction cup plate 311 has interconnected ventilation channels 3112 machined inside. All ventilation channels 3112 eventually converge below the center of the suction cup plate 311 and are connected to the ventilation shaft 33. When an external vacuum source evacuates through the ventilation shaft 33, the suction cups 313 suck up the wafer workpiece 2 and deform downward due to the negative pressure, so that the bottom surface of the wafer workpiece 2 is tightly pressed and pulled down to the surface of the rigid suction cup cover plate 312. This ingenious design utilizes both the flexible adsorption of the suction cups 313 and the rigid support of the suction cup cover plate 312 to achieve extremely high clamping flatness.

[0053] Continue reading Figure 7 It is known that the moving module 8 includes a slide rail assembly 81 and a lifting assembly 82. The slide rail assembly 81 includes a horizontal slide rail 811 disposed on the upper part of the inner wall of one side of the mounting frame 7. The lifting assembly 82 moves along the horizontal slide rail 811 in the X direction via a slider 812. The lifting assembly 82 includes a U-shaped frame 821 and a lifting platform 822. The U-shaped frame 821 cooperates with the horizontal slide rail 811 via the slider 812. The lifting platform 822 is disposed inside the U-shaped frame 821 and is driven by a lead screw 823 and a motor 824 to move up and down between the upper and lower walls of the U-shaped frame 821. The polishing tool module 1 is suspended by mounting plates 825 disposed on both sides of the lifting platform 822.

[0054] In this embodiment, the polishing tank 4 is mounted on the mounting frame 7, and its overall size encompasses the polishing tool module 1 and the workpiece fixture module 3. The tank wall of polishing tank 4 is higher than the processing surface of polishing tool module 1 to receive and return all the polishing fluid. The bottom outlet of polishing tank 4 is connected to a stirrer 6, which continuously stirs the recovered polishing fluid to prevent abrasive particle sedimentation. The inlet of peristaltic pump 5 is connected to the stirrer 6, and the outlet is connected to the polishing fluid transfer tank 14 at the top of polishing tool module 1. Peristaltic pump 5 can effectively transport high-viscosity non-Newtonian fluids, providing a stable flow rate for polishing tool module 1. The shear-thickened polishing fluid consists of a shear thickener, deionized water-based fluid, dispersant, and abrasive particles. By weight percentage, it includes 35wt%-40wt% of shear thickener (preferably tapioca starch), 20wt%-30wt% of deionized water-based liquid, 10wt% of dispersant (preferably polyethylene glycol), and 30wt%-35wt% of abrasive particles (preferably nano-sized alumina particles).

[0055] Example 2

[0056] This embodiment provides a polishing method for anisotropic materials using array rheological polishing. It is implemented using the apparatus for array rheological polishing of anisotropic materials described in Embodiment 1, and utilizes a material removal function coupled with shear-thickening fluid dynamics and abrasive contact mechanics for quantitative processing. The method specifically includes the following steps:

[0057] Step S1: Use a white light interferometer to measure the original surface roughness and flatness of the single-crystal wafer workpiece 2 to determine the target surface shape to be achieved, and calculate the absolute material removal depth to be processed. Then, the wafer workpiece 2 is placed into the shallow circular groove of the suction cup cover plate 303 of the workpiece fixture module 3, aligned with the original crystal orientation of the V-groove, and the vacuum is activated to cause the suction cup 302 to contract and fix the wafer workpiece 2.

[0058] Step S2: Prepare the shear-thickening polishing solution. Add 35wt%-40wt% tapioca starch, 20wt%-30wt% deionized water, 10wt% polyethylene glycol, and 30wt%-35wt% nano-sized alumina particles to stirrer 6 and mix thoroughly. Extract a small sample and use a rheometer to determine the shear stress-shear rate data. The consistency coefficient and rheological index of the fluid were obtained by fitting. The peristaltic pump 5 was started to circulate the polishing fluid in the polishing fluid circulation mechanism and immerse the polishing area.

[0059] Step S3: Set key process parameters through the control system, including the polishing wheel speed. The machining gap between the polishing wheel and the workpiece is controlled in a closed loop by the laser displacement sensor 108. The feed rate of the polishing tool module 1 driven by the moving module 8 Start the polishing tool module 1 and perform the first process of unidirectional pure shear polishing on the

[100] crystal direction of the wafer workpiece 2.

[0060] Step S4: Based on the material removal analysis function of the polishing system unique to this device, calculate the amount of material removed in a single full-stroke scan, and then obtain the required total number of reciprocating polishing cycles N; when the number of reciprocating cycles reaches the set N, the first process automatically stops.

[0061] Material removal depth The formula is as follows:

[0062] ,

[0063] in,

[0064] ,

[0065] ,

[0066] in,

[0067] ,

[0068] ,

[0069] ,

[0070] In the formula, , The material-chemical coupling constant, This is the dynamic pressure shape factor. The abrasive grain mass concentration, The average particle size of the abrasive grains. This is the consistency coefficient of the polishing slurry. The radius of the polishing wheel, The hardness of the workpiece material. The linear velocity of the polishing wheel's rotation. For tool feed rate, This is the polishing gap.

[0071] Step S5: Control the rotary cylinder 34 to ventilate, driving the ventilation shaft 33, suction cup 313, and wafer workpiece 2 to rotate precisely 90 degrees. No secondary clamping and repositioning is required; directly repeat steps S3 and S4 to perform the second polishing process along the

[010] crystal orientation of the wafer workpiece 2. After processing, stop the equipment, release the vacuum, and remove the wafer workpiece 2 with a nanoscale, non-destructive, and flat surface.

[0072] like Figure 8 The image shown is a display of the surface morphology and roughness obtained at random point 1 after array rheological polishing in a specific embodiment of the present invention. Figure 9 The image shown is a diagram illustrating the surface morphology and roughness obtained at random point 2 after array rheological polishing in a specific embodiment of the present invention.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An apparatus for array rheological polishing of anisotropic materials, comprising a mounting frame (7), characterized in that, A polishing pool (4) is provided in the middle of the mounting frame (7). A workpiece clamping module (3) is provided in the polishing pool (4) to fix the wafer workpiece (2) and perform 90-degree rotation positioning. A polishing tool module (1) is provided on the workpiece clamping module (3). The polishing tool module (1) is movably set in the mounting frame (7) through a moving module (8). The polishing tool module (1) moves back and forth above the wafer workpiece (2) to maintain non-contact shear thickening polishing of the surface of the wafer workpiece (2) in a single direction. The polishing pool (4) together with the peristaltic pump (5) and the stirrer (6) set in the mounting frame (7) constitute a polishing liquid circulation mechanism to prepare, stir evenly and deliver shear thickening polishing liquid to the polishing tool module (1), while recovering the outflowing polishing liquid to form a closed loop circulation. The device utilizes a material removal function coupled with shear-thickening fluid dynamics and abrasive contact mechanics for quantitative processing. The polishing method of the device specifically includes the following steps: Step S1: Use a white light interferometer to measure the original surface roughness and flatness of the wafer workpiece (2), determine the target surface shape to be achieved, and calculate the absolute material removal depth to be processed. The wafer workpiece (2) is placed into the workpiece clamping module (3) and vacuum-clamped. Step S2: Prepare the shear-thickening polishing slurry. Mix 35wt%-40wt% shear thickener, 20wt%-30wt% deionized water-based liquid, 10wt% dispersant, and 30wt%-35wt% abrasive particles uniformly according to their mass percentages. Measure the shear stress-shear rate data of the polishing slurry using a rheometer. Add polishing slurry to the polishing slurry circulation mechanism and start it; Step S3: After setting the process parameters, start the first polishing process of the [100] crystal orientation of the wafer workpiece (2). The set process parameters include the polishing wheel speed. The machining clearance between the polishing wheel and the workpiece The moving speed of the polishing tool ; Step S4: Calculate the material removal depth of a single polishing stroke. ,according to The number of times the polishing tool reciprocates (N) is used; the material removal depth is obtained. The calculation formula is as follows: ， In the formula, , The material-chemical coupling constant, This is the dynamic pressure shape factor. The abrasive grain mass concentration, The average particle size of the abrasive grains. This is the consistency coefficient of the polishing slurry. The radius of the polishing wheel, The hardness of the workpiece material. The linear velocity of the polishing wheel's rotation. For tool feed rate, For polishing gaps; Step S5: The fixture module rotates the workpiece 90 degrees to perform the second polishing process of the [010] crystal orientation of the wafer workpiece (2).

2. The apparatus for array rheological polishing of anisotropic materials according to claim 1, characterized in that, The polishing tool module (1) includes a rectangular box (16) with an open bottom. A forward rotation component (10) and a reverse rotation component (11) are arranged side-by-side inside the rectangular box (16). The forward rotation component (10) includes a forward rotation servo motor (101) and two forward rotation polishing wheels (102) driven by the forward rotation servo motor (101). The reverse rotation component (11) includes a reverse rotation servo motor (111) and two reverse rotation polishing wheels (112) driven by the reverse rotation servo motor (111). The two forward rotation polishing wheels (102) and the two reverse rotation polishing wheels (112) are arranged parallel to each other along the length of the rectangular box (16). The polishing wheel (102) and the reverse polishing wheel (112) have the same structure, and polishing liquid nozzles (12) are provided between the two forward polishing wheels (102), between the two reverse polishing wheels (112), and between the forward component (10) and the reverse component (11). The forward servo motor (101) drives the two forward polishing wheels (102) to rotate clockwise through a synchronous pulley group (13) to drive the polishing liquid to polish the surface of the wafer workpiece (2) and to discharge the polishing liquid to the outside. The reverse servo motor (111) drives the two reverse polishing wheels (112) to rotate counterclockwise through another synchronous pulley group (13) and to discharge the polishing liquid to the outside.

3. The apparatus for array rheological polishing of anisotropic materials according to claim 2, characterized in that, The polishing liquid nozzle (12) has a row of long holes at the bottom. The length of the polishing liquid nozzle (12) is similar to the axial length of the forward-rotating polishing wheel (102) and the reverse-rotating polishing wheel (112). A polishing liquid transfer box (14) is provided on the rectangular box (16). The top of the polishing liquid transfer box (14) is provided with a polishing liquid inlet, and one side is connected to three liquid outlet pipes that are respectively connected to the three polishing liquid nozzles (12) to buffer the pumped polishing liquid and evenly distribute the polishing liquid into the three polishing liquid nozzles (12).

4. The apparatus for array rheological polishing of anisotropic materials according to claim 2, characterized in that, The rectangular box (16) is provided with laser displacement sensors (15) on both outer walls along its length direction to measure in real time the distance between the bottom of the forward polishing wheel (102) and the reverse polishing wheel (112) and the surface of the wafer workpiece (2).

5. The apparatus for array rheological polishing of anisotropic materials according to claim 2, characterized in that, The workpiece clamping module (3) includes a circular suction cup assembly (31). Polishing plates (32) are provided on both sides of the suction cup assembly (31) to receive the overflowing polishing liquid and provide a transition overtravel area for the polishing tool module (1). A ventilation shaft (33) is provided in the lower middle part of the suction cup assembly (31). The bottom end of the ventilation shaft (33) is mounted on a rotary cylinder (34). After the rotary cylinder (34) is ventilated, it can drive the ventilation shaft (33) and the suction cup assembly (31) above it to rotate 90 degrees.

6. The apparatus for array rheological polishing of anisotropic materials according to claim 5, characterized in that, The suction cup assembly (31) includes a suction cup plate (311) and a suction cup cover plate (312). A plurality of suction cups (313) are evenly spaced on the suction cup plate (311). The suction cup cover plate (312) covers the suction cup plate (311) and has through holes for the suction cups (313) to pass through. The height of the suction cups (313) in their natural state is higher than the upper surface of the suction cup cover plate (312). The suction cup cover plate (312) has a recessed circular shallow groove on its surface for positioning a circular wafer workpiece (2), and a V-shaped groove for positioning the crystal orientation of the wafer workpiece (2).

7. The apparatus for array rheological polishing of anisotropic materials according to claim 6, characterized in that, The upper surface of the suction cup plate (311) is provided with a suction cup thread hole (3111) for mounting the suction cup (313). The suction cup plate (311) has interconnected ventilation channels (3112) inside. All ventilation channels (3112) eventually converge below the center of the suction cup plate (311) and are connected to the ventilation shaft (33). When the external vacuum source draws a vacuum through the ventilation shaft (33), the suction cup (313) sucks up the wafer workpiece (2) and deforms downward due to the negative pressure, so that the bottom surface of the wafer workpiece (2) is tightly attached and pulled down to the surface of the hard suction cup cover plate (312).

8. The apparatus for array rheological polishing of anisotropic materials according to any one of claims 1-7, characterized in that, The moving module (8) includes a slide rail assembly (81) and a lifting assembly (82). The slide rail assembly (81) includes a horizontal slide rail (811) disposed on the upper part of the inner wall of one side of the mounting frame (7). The lifting assembly (82) moves along the horizontal slide rail (811) in the X direction via a slider (812). The lifting assembly (82) includes a U-shaped frame (821) and a lifting platform (822). The U-shaped frame (821) cooperates with the horizontal slide rail (811) via a slider (812). The lifting platform (822) is disposed inside the U-shaped frame (821) and is driven by a lead screw (823) and a motor (824) to move up and down between the upper and lower walls of the U-shaped frame (821). The polishing tool module (1) is suspended by mounting plates (825) disposed on both sides of the lifting platform (822).

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