A composite grinding and polishing structure design for wafer-level grinding and polishing process and a grinding and polishing method thereof

Abstract

This invention relates to a composite polishing structure design and polishing method for wafer-level polishing processes. The composite polishing structure design includes a disk body with a positioning groove at the center of its upper end. An upper Tesla groove, a lower Tesla groove, and an annular channel are arranged on the disk body around the positioning groove. The upper and lower Tesla grooves are arranged in a circumferentially spaced array and extend radially. The upper and lower Tesla grooves are arranged vertically and circumferentially adjacent. The inner ends of both the upper and lower Tesla grooves penetrate the positioning groove, and their outer ends penetrate the outer circumferential surface of the disk body. The annular channel is arranged radially around the disk body and penetrates both the upper and lower Tesla grooves. This invention forms an integrated fluid guidance and waste chip discharge channel through the double-layer Tesla grooves, improving the utilization efficiency and chip removal capacity of the polishing fluid.

Description

Technical Field

[0001] This invention belongs to the field of wafer thinning and polishing technology, specifically relating to a composite polishing structure design and polishing method for wafer-level polishing processes. Background Technology

[0002] With the increasing demand for pressure monitoring in high-temperature environments (≥800℃) for equipment such as aero-engines and gas turbines, high-temperature resistant fiber optic FP (Fabry-Perot) pressure sensors have become crucial devices for measurements in extreme high-temperature environments due to their advantages such as low invasiveness and high consistency. The sensitive structure of the pressure sensor plays a decisive role in its performance, requiring the pressure-sensitive diaphragm thickness to reach the micrometer level (below 60μm) and the bonding surface roughness Ra to be less than 0.3nm. Existing grinding and polishing equipment struggles to simultaneously achieve material removal rate and film thickness uniformity, specifically manifested in the following ways: (1) Uneven distribution of polishing slurry: Traditional disks mostly adopt open planar or simple grid groove structure. Under high-speed rotation, under the dominance of centrifugal force, the polishing slurry tends to be thrown out quickly in the radial direction to the edge of the disk. The lack of an effective flow resistance structure to "lock" the polishing slurry in the central area of ​​the wafer results in the central area being in a "short slurry" state, while the edge area has an excess of polishing slurry, resulting in a serious inconsistency in the material removal rate between the center and the edge.

[0003] (2) Waste accumulation and scratches: Existing devices usually adopt a "single-layer groove" design, where the polishing fluid and the waste liquid containing cutting waste (such as broken abrasive grains and reaction products) share the same flow layer. Due to the lack of an independent settling and stratification channel, large particles of waste cannot be discharged in time and repeatedly circulate with the fluid in the processing area, resulting in a decrease in the cleanliness of the processing area. Hard waste is very likely to cause micro-scratches on the surface of the ultra-thin sensitive diaphragm or cause local stress concentration.

[0004] (3) Edge overshoot: According to Preston's equation MRR∝Pv Material removal rate is directly proportional to relative linear velocity. During eccentric wafer grinding, the linear velocity at the wafer edge is significantly higher than that at the center. Existing trench depths are typically uniform and cannot provide flow field compensation for radius variations. In the high-velocity edge region, excessive fluid shear force leads to excessively rapid material removal, ultimately resulting in a bowl-shaped thickness distribution and structural failure. Therefore, traditional single-layer trench structures lack comprehensive control over flow direction, pressure differential regulation, and waste liquid recovery, failing to meet the fabrication requirements of sapphire / silicon carbide ultrathin sensitive structures in high-temperature sensors. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a composite polishing structure design and polishing method for wafer-level polishing processes. By constructing a double-layer Tesla valve array trench to guide forward flow and suppress reverse chipping, an integrated fluid guidance and chip discharge channel is formed, improving the utilization efficiency and chip removal capacity of the polishing fluid, avoiding over-polishing of wafer edges, and achieving uniform control of wafer thickness.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A composite polishing structure design for wafer-level polishing processes includes a disk body. A positioning groove is provided at the center of the upper end of the disk body. An upper Tesla trench, a lower Tesla trench, and an annular channel are provided on the disk body located on the outer periphery of the positioning groove. The upper Tesla trench and the lower Tesla trench are arranged in a circumferentially spaced array and extend radially along the disk body. The upper Tesla trench and the lower Tesla trench are arranged vertically spaced and circumferentially adjacent. The inner ends of the upper Tesla trench and the lower Tesla trench both penetrate the positioning groove, and their outer ends both penetrate the outer peripheral surface of the disk body. The annular channel sequentially loops around the disk body at radial intervals and penetrates both the upper Tesla trench and the lower Tesla trench.

[0007] Furthermore, the upper Tesla trench includes several upper micro Tesla valve units connected in series for guiding the forward flow of the polishing fluid, and the lower Tesla trench includes several lower micro Tesla valve units connected in series for reverse flow resistance.

[0008] Furthermore, the upper Tesla trench also includes an upper starting section trench and an upper tail section trench, the upper starting section trench and the upper tail section trench are straight, and an upper middle section trench is connected in series between the upper starting section trench and the upper tail section trench, the upper middle section trench being a plurality of upper micro Tesla valve units connected in series.

[0009] Furthermore, the lower Tesla trench also includes a lower starting section trench and a lower tail section trench, both of which are straight. A lower middle section trench is connected in series between the lower starting section trench and the lower tail section trench, and the lower middle section trench is a plurality of lower micro Tesla valve units connected in series.

[0010] Furthermore, the upper micro Tesla valve unit includes an upper first Tesla flow channel and an upper second Tesla flow channel, which are connected in series in opposite directions.

[0011] Furthermore, the upper first Tesla flow channel includes an upper inlet section, an upper first wing-shaped obstruction flow channel, an upper first lower inclined flow channel, and an upper first upper inclined flow channel. One end of the upper first wing-shaped obstruction flow channel is connected to one end of the upper first upper inclined flow channel and then connects to the upper inlet section. The other end of the upper first wing-shaped obstruction flow channel is connected to one end of the upper first lower inclined flow channel. The other end of the upper first lower inclined flow channel and the other end of the upper first upper inclined flow channel are connected to an upper intermediate transition section. The upper second Tesla flow channel includes an upper outlet section, an upper second wing-shaped obstruction flow channel, and an upper second... The upper second wing-shaped obstruction channel and the upper second upper wing-shaped obstruction channel are connected together at one end to the upper second lower wing-shaped obstruction channel and then connected to the upper intermediate transition section. The other end of the upper second wing-shaped obstruction channel is connected to one end of the upper second upper wing-shaped obstruction channel. The other end of the upper second lower wing-shaped obstruction channel and the other end of the upper second upper wing-shaped obstruction channel are connected together and then connected to the upper outlet section. The upper first wing-shaped obstruction channel and the upper second wing-shaped obstruction channel are both arc-shaped channels. The upper first lower wing-shaped obstruction channel, the upper first upper wing-shaped obstruction channel, the upper second lower wing-shaped obstruction channel and the upper second upper wing-shaped obstruction channel are all straight channels.

[0012] Furthermore, the lower micro Tesla valve unit includes a lower first Tesla flow channel and a lower second Tesla flow channel, which are connected in series in opposite directions.

[0013] Furthermore, the lower first Tesla flow channel includes a lower inlet section, a lower first obstruction flow channel, a lower first downward-sloping flow channel, and a lower first upward-sloping flow channel. One end of the lower first obstruction flow channel connects to one end of the lower first upward-sloping flow channel and then connects to the lower inlet section. The other end of the lower first obstruction flow channel connects to one end of the lower first downward-sloping flow channel. The other end of the lower first downward-sloping flow channel connects to the other end of the lower first upward-sloping flow channel and then connects to a lower intermediate transition section. The lower second Tesla flow channel includes a lower outlet section, a lower second obstruction flow channel, a lower second downward-sloping flow channel, and a lower first... The second obstruction channel has one end connected to the second lower obstruction channel and then to the lower intermediate transition section. The other end of the second obstruction channel is connected to one end of the second lower obstruction channel. The other end of the second lower obstruction channel and the other end of the second lower obstruction channel are connected to the lower outlet section. The first obstruction channel, the first lower obstruction channel, and the first lower obstruction channel are connected in series to form a first triangular channel. The second obstruction channel, the second lower obstruction channel, and the second lower obstruction channel are connected in series to form a second triangular channel.

[0014] Furthermore, the depth of the upper or lower Tesla trench increases non-linearly from the center to the outer periphery along the radial direction of the disk, and the non-linear increasing function is: ; Where H0 is the initial depth of the upper or lower Tesla trench, k is the trench depth compensation coefficient, and Rmax r is the maximum radius of the disk body, and r is the groove depth. The radius at point n is a nonlinear exponent, where n ≥ 2.

[0015] This invention also provides a polishing method for wafer-level polishing processes, and a composite polishing structure design for wafer-level polishing processes based on this invention. The method includes the following steps: Step S1: Fix the wafer to be processed onto the disk; Step S2: Connect the polishing fluid to the positioning groove of the disc body; Step S3: Start the disk rotation. Under the action of centrifugal force, the polishing fluid flows forward along the upper Tesla groove and acts between the disk and the wafer. The polishing waste generated by polishing settles into the lower Tesla groove through the annular channel and is discharged out of the disk body by one-way guide.

[0016] Because the present invention adopts the above technical solution, it has the following advantages and effects: This invention provides a composite polishing structure design and polishing method for wafer-level polishing processes. Through the differentiated design of a double-layer Tesla valve array, a bidirectional flow control system is formed, which improves the forward flow velocity of the polishing fluid and suppresses the reverse backflow of waste chips, ensuring that the polishing fluid covers the wafer processing surface in one direction. Furthermore, the depth difference of the double-layer Tesla grooves creates a fluid velocity gradient, enabling automatic stratification of nano-sized abrasives and micron-sized waste chips, forming a stratified chip removal mechanism. This ensures that the polishing fluid and large-particle waste chips are discharged in a timely manner, avoiding scratches on the wafer surface and extending the service life of the polishing fluid.

[0017] This invention provides a composite polishing structure design and polishing method for wafer-level polishing processes. By using nonlinear depth compensation of trench depth variation through wafer eccentric arrangement and centrifugal acceleration distribution, it effectively alleviates edge over-polishing and optimizes wafer thickness consistency. Furthermore, during wafer thinning, the waste debris (particles, reaction products, etc.) generated by wear is carried by the polishing liquid flow, flows into the annular channel of the ramp structure through the upper Tesla trench, and sinks to the lower Tesla trench. The upper Tesla trench provides "reverse high resistance" characteristics, effectively preventing waste liquid from flowing back to the wafer area. Utilizing the centrifugal force generated by the rotation of the disk, the waste liquid is driven to be discharged along the trench direction towards the edge, and finally collected in the outer drainage tank. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the disc body designed for the composite grinding and polishing structure of the present invention.

[0019] Figure 2 This is a partially enlarged front view of part C of the present invention.

[0020] Figure 3 This is a partially enlarged front view of part A of the present invention.

[0021] Figure 4 This is a partially enlarged front view of part B of the present invention.

[0022] The attached diagram is labeled as follows: 1 - disc body, 2 - positioning groove, 3 - upper Tesla groove, 4 - lower Tesla groove, 31 - upper first wing-shaped obstruction channel, 32 - upper first downward sloping channel, 33 - upper first upward sloping channel, 34 - upper inlet section, 35 - upper intermediate transition section, 36 - upper second downward sloping channel, 37 - upper second wing-shaped obstruction channel, 38 - upper second upward sloping channel, 39 - upper outlet section, 41 - lower first obstruction channel, 42 - lower first downward sloping channel, 43 - lower first upward sloping channel, 44 - lower inlet section, 45 - lower intermediate transition section, 46 - lower second downward sloping channel, 47 - lower second obstruction channel, 48 - lower second upward sloping channel, 49 - lower outlet section, 5 - annular channel. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings to provide a clearer understanding of the purpose, features, and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative of the essential spirit of the technical solution of the present invention.

[0024] like Figure 1 - Figure 4 As shown, this invention discloses a composite polishing structure design for wafer-level polishing processes, comprising a disk body 1. A positioning groove 2, which is a circular groove, is located at the center of the upper end of the disk body 1. An upper Tesla groove 3, a lower Tesla groove 4, and an annular channel 5 are arranged on the disk body 1 around the positioning groove 2. The upper Tesla groove 3 and the lower Tesla groove 4 are arranged in a circumferentially spaced array and extend radially along the disk body 1. The upper Tesla groove 3 and the lower Tesla groove 4 are arranged vertically spaced and circumferentially adjacent. The inner ends of both the upper Tesla groove 3 and the lower Tesla groove 4 penetrate the positioning groove 2, and their outer ends penetrate the outer circumferential surface of the disk body 1. The annular channel 5 is a sloping structure, sequentially arranged radially around the disk body 1 and penetrating both the upper Tesla groove 3 and the lower Tesla groove 4, forming a layered fluid passage. The layered fluid passage ensures that the failed polishing fluid and large particles of waste are discharged in a timely manner, avoiding scratches on the wafer surface and extending the service life of the polishing fluid.

[0025] Furthermore, the upper Tesla trench 3 is composed of an upper starting section trench, an upper middle section trench, and an upper tail section trench connected sequentially. The upper starting section trench and the upper tail section trench are straight lines, while the upper middle section trench consists of series-connected upper micro Tesla valve units. These upper micro Tesla valve units guide the forward flow of the polishing fluid. The lower Tesla trench 4 is composed of a lower starting section trench, a lower middle section trench, and a lower tail section trench connected sequentially. The lower starting section trench and the lower tail section trench are straight lines, while the lower middle section trench consists of series-connected lower micro Tesla valve units. These lower micro Tesla valve units collect polishing debris and provide reverse flow resistance.

[0026] Furthermore, the upper micro Tesla valve unit includes an upper first Tesla flow channel and an upper second Tesla flow channel, which are connected in series in opposite directions.

[0027] The upper first Tesla flow channel includes an upper inlet section 34, an upper first wing-shaped obstruction flow channel 31, an upper first lower inclined flow channel 32, and an upper first upper inclined flow channel 33. One end of the upper first wing-shaped obstruction flow channel 31 is connected to one end of the upper first upper inclined flow channel 33 and then connected to the upper inlet section 34. The other end of the upper first wing-shaped obstruction flow channel 31 is connected to one end of the upper first lower inclined flow channel 32. The other end of the upper first lower inclined flow channel 32 is connected to the other end of the upper first upper inclined flow channel 33 and then connected to the upper intermediate transition section 35. The upper second Tesla flow channel includes an upper outlet section 39, an upper second wing-shaped obstruction flow channel 37, an upper second lower slope flow channel 36, and an upper second upper slope flow channel 38. One end of the upper second wing-shaped obstruction flow channel 37 connects to one end of the upper second lower slope flow channel 36 and then connects to the upper intermediate transition section 35. The other end of the upper second wing-shaped obstruction flow channel 37 connects to one end of the upper second upper slope flow channel 38. The other end of the upper second lower slope flow channel 36 connects to the other end of the upper second upper slope flow channel 38 and then connects to the upper outlet section 39. The upper first wing-shaped obstruction flow channel 31 and the upper second wing-shaped obstruction flow channel 37 are both arc-shaped flow channels, while the upper first lower slope flow channel 32, the upper first upper slope flow channel 33, the upper second lower slope flow channel 36, and the upper second upper slope flow channel 38 are all straight flow channels.

[0028] The polishing fluid enters from the upper inlet section 34, and one path flows through the upper first upward-sloping channel 33 into the upper intermediate transition section 35. The other path flows in the forward direction, around the upper first wing-shaped obstruction channel 31, then through the upper first downward-sloping channel 32, and enters the upper intermediate transition section 35 to merge with the first path. After merging, the fluid splits again. The first path flows through the upper second downward-sloping channel 36 into the upper outlet section 39, while the second path flows in the reverse direction, around the upper second wing-shaped obstruction channel 37, then through the upper second upward-sloping channel 38, and enters the upper outlet section 39 to mix again. The polishing fluid forms flow resistance within the upper first wing-shaped obstruction channel 31 and the upper wing-shaped obstruction channel 37.

[0029] As a preferred embodiment, the upper first wing-shaped obstruction channel 31 and the upper second wing-shaped obstruction channel 37 have the same structure, the upper first upward oblique channel 33 and the upper second upward oblique channel 38 have the same structure, and the upper first downward oblique channel 32 and the upper second downward oblique channel 36 have the same structure.

[0030] Furthermore, the lower micro Tesla valve unit includes a lower first Tesla flow channel and a lower second Tesla flow channel, which are connected in series in opposite directions.

[0031] The lower first Tesla flow channel includes a lower inlet section 44, a lower first obstruction flow channel 41, a lower first downward slope flow channel 42, and a lower first upward slope flow channel 43. One end of the lower first obstruction flow channel 41 is connected to one end of the lower first upward slope flow channel 43 and then connected to the lower inlet section 44. The other end of the lower first obstruction flow channel 41 is connected to one end of the lower first downward slope flow channel 42. The other end of the lower first downward slope flow channel 42 is connected to the other end of the lower first upward slope flow channel 43 and then connected to the lower intermediate transition section 45. The lower second Tesla flow channel includes a lower outlet section 49, a lower second obstruction flow channel 47, a lower second downward-sloping flow channel 46, and a lower second upward-sloping flow channel 48. One end of the lower second obstruction flow channel 47 connects to one end of the lower second downward-sloping flow channel 46 and then connects to the lower intermediate transition section 45. The other end of the lower second obstruction flow channel 47 connects to one end of the lower second upward-sloping flow channel 48. The other end of the lower second downward-sloping flow channel 46 connects to the other end of the lower second upward-sloping flow channel 48 and then connects to the lower outlet section 49. The lower first obstruction flow channel 41, the lower first downward-sloping flow channel 42, and the lower first upward-sloping flow channel 43 are connected in series to form a first triangular flow channel. The lower second obstruction flow channel 47, the lower second downward-sloping flow channel 46, and the lower second upward-sloping flow channel 48 are connected in series to form a second triangular flow channel. The axis of the lower first obstruction channel 41 and the axis of the lower first upward obstruction channel 43 intersect at an acute angle, forming an acute angle protrusion. The axes of the lower second obstruction channel 47 and the lower second downward obstruction channel 46 intersect at an acute angle, forming an acute angle protrusion.

[0032] As a preferred embodiment, the lower first obstruction flow channel 41 and the lower second obstruction flow channel 47 have the same structure, the lower first upper inclined flow channel 43 and the lower second upper inclined flow channel 48 have the same structure, and the lower first lower inclined flow channel 42 and the lower second lower inclined flow channel 46 have the same structure.

[0033] The polishing fluid enters from the lower inlet section 44, and one path flows through the lower first upward-sloping channel 43 into the lower intermediate transition section 45. The other path flows through the lower first obstruction channel 41, then through the lower first downward-sloping channel 42, and then into the lower intermediate transition section 45 to merge with the first path. After merging, the fluid splits again. The first path after splitting flows through the lower second downward-sloping channel 46 into the lower outlet section 49, and the second path after splitting flows through the lower second obstruction channel 47 and the lower second upward-sloping channel 48 before entering the lower outlet section 49 and mixing again.

[0034] In the lower micro-Tesla valve unit, the polishing fluid utilizes the Coanda effect and fluid collision principle. During the polishing process, the wear debris is carried by the polishing fluid flow, flowing through the upper Tesla groove 3 into the annular channel 5 and settling into the lower Tesla groove 4. When the debris settles into the lower Tesla groove 4 with the polishing fluid, if there is a tendency to flow back towards the center due to turbulence or pressure fluctuations, the fluid will be captured by the lower first Tesla channel and the lower second Tesla channel with sharp-angled protrusions and guided back to the main path, colliding with the reverse mainstream to form a high-resistance barrier. This "fluid diode" characteristic ensures that the debris can only be discharged outward in one direction. By utilizing the centrifugal force generated by the rotation of the disc 1, the waste liquid is driven to the edge and finally collected in the outer drainage tank.

[0035] Furthermore, the groove depth of the upper Tesla groove 3 or the lower Tesla groove 4 increases nonlinearly from the center to the outer periphery along the radial direction of the disk 1. That is, the groove depth H(r) of each connected upper or lower micro Tesla valve unit forms a stepped or continuous slope-like depth gradient. The change in the groove depth H(r) of the upper Tesla groove 3 or the lower Tesla groove 4 offsets the increase in centrifugal acceleration and linear velocity caused by the increase in the radius of the polishing disk 1. According to fluid lubrication theory, the fluid shear stress is reduced by increasing the groove depth at the edge. Therefore, the nonlinearly increasing function is: ; Where H0 is the initial depth of the upper Tesla trench 3 or the lower Tesla trench 4; k is the trench depth compensation coefficient; R max The maximum radius of the disk body; r is the groove depth The radius at that location; n is a nonlinear exponent, n≥2, preferably 2.

[0036] In this invention, the depths of the upper Tesla trench 3 and the lower Tesla trench 4 follow a hydrodynamic compensation mechanism. During the polishing process, the linear velocity at the wafer edge is significantly higher than that at the center. According to the Preston equation, if the pressure is uniform, the edge removal rate will be too high. As the radius increases, the trench depth increases, resulting in a thicker liquid film of the polishing fluid contained locally. According to fluid lubrication theory, the increased liquid film thickness effectively reduces the shear stress of the fluid on the wafer surface.

[0037] This invention guides the polishing fluid to form velocity gradients and pressure differences in different radius regions by setting a nonlinear gradient (increasing from the center outwards) along the radial direction of the trench depth. This is used to compensate for the changes in centrifugal acceleration caused by the eccentric arrangement of the wafer, and to achieve dynamic adjustment of the over-polishing phenomenon at the edge. In particular, it addresses the excessive material removal that is prone to occur at the edge of the wafer. By setting the increasing law of the trench depth, the local flow rate and shear force are reduced, and precise thickness control is achieved.

[0038] This invention also provides a polishing method for wafer-level polishing processes, and applies a composite polishing structure design for wafer-level polishing processes according to this invention. The method includes the following steps: Step S1: Select the appropriate disk 1 and install it onto the spindle of the equipment as needed. Fix the sapphire or silicon carbide wafer to be processed onto the wafer fixture by vacuum adsorption. The wafer fixture is placed in the off-center area between the center and the edge of the surface of the disk 1 (preferably set within the range of 60mm-80mm from the center) to form an effective relative motion area.

[0039] Step S2: Start the polishing fluid injection system and slowly inject the pre-mixed polishing fluid into the positioning groove 2 of the disc body 1.

[0040] Step S3: Start the rotation of disk 1. Under the action of centrifugal force, the polishing fluid flows forward along the upper Tesla groove 3 and acts between disk 1 and wafer, uniformly covering the entire wafer surface. During the flow of the polishing fluid, the pressure control enables the high-speed moving polishing fluid in the upper Tesla groove 3 to drive the abrasive particles to remove material from the wafer surface. The fluid shear and friction of the polishing fluid jointly provide the kinetic energy for polishing (thinning or polishing). The polishing waste generated by the polishing is carried by the polishing fluid and settles into the lower Tesla groove 4 through the annular channel 5 and is unidirectionally discharged to the periphery of disk 1.

[0041] Example 1 Example 1 is adapted to the high-efficiency thinning process of ultra-thin sensitive structures of sapphire / silicon carbide pressure sensors.

[0042] In Example 1, the flow velocity in the upper Tesla trench 3 is accelerated to form a high-speed laminar flow, which promotes the continuous distribution of abrasive particles in the polishing fluid and enhances the material removal rate. The lower Tesla trench 4 captures waste particles through negative pressure difference and gravity, preventing backflow and contamination of the processing surface. The nonlinear trench depth increases radially, forming a gradually increasing flow resistance and liquid film thickness to adjust the shear force of the edge polishing fluid and achieve edge compensation for wafer thickness.

[0043] In Example 1, the disk body 1 has a radius of 15cm. A positioning groove 2 with a radius of 1cm is located at the center of the disk body 1. The surface of the disk body 1 is provided with two layers of annular arrayed long grooves. The upper long groove is the upper Tesla groove 3, and the lower long groove is the lower Tesla groove 4. In the upper Tesla groove 3, the middle section of the upper layer is 12cm long, and the groove depth of the upper Tesla groove 3 is 0.08mm–0.48mm.

[0044] In Example 1, the inlet width of the upper inlet section 34 is 0.3 mm. The width at the intersection of the upper first wing-shaped obstruction channel 31 and the upper first upward-sloping channel 33 is the same as the width at the intersection of the upper second wing-shaped obstruction channel 37 and the upper second downward-sloping channel 36, and the width is increased to 2 mm. The width of the upper first wing-shaped obstruction channel 31, the upper first downward-sloping channel 32 and the upper first upward-sloping channel 33 are all 0.2 mm. The width of the upper intermediate transition section 35 is 0.4 mm. The outlet width of the upper outlet section 39 is 0.3 mm.

[0045] In the lower Tesla trench 4, the length of the middle section of the lower layer trench is 12cm, and the depth of the lower Tesla trench 4 is 0.15mm-0.7mm.

[0046] The inlet width of the lower inlet section 44 is 3mm. The width of the intersection of the lower second obstruction channel 41 and the lower first upward obstruction channel 43 is the same as the width of the intersection of the lower second obstruction channel 47 and the lower second downward obstruction channel 46, and the width is expanded to 10mm. The width of the lower second obstruction channel 41, the lower first downward obstruction channel 42 and the lower first upward obstruction channel 43 is 2mm. The width of the lower intermediate transition section 45 is 4mm. The width of the outlet of the lower outlet section 49 is 3mm.

[0047] The preferred material for the disc body 1 in Example 1 is diamond.

[0048] Example 2 Example 2 is adapted to the polishing process of ultra-thin sensitive structures of sapphire / SiC pressure sensors.

[0049] In Example 2, the upper Tesla trench 3 enables micro-control of the liquid film and reduces the edge flow velocity in conjunction with the nonlinear depth distribution. The lower Tesla trench 4 is a damped expansion trench that uses rotational centrifugal force and fluid inertia to guide the waste liquid in one direction, thereby improving the surface quality of nanoscale processing.

[0050] Unlike Example 1, in Example 2, the depth of the upper Tesla trench 3 is 0.9μm-18μm, the width of the inlet end of the upper inlet section 34 is 30μm, the width of the intersection of the upper first wing-shaped obstruction channel 31 and the upper first upward obstruction channel 33, and the width of the intersection of the upper second wing-shaped obstruction channel 37 and the upper second downward obstruction channel 36 are the same, all widened to 100μm, the width of the upper first wing-shaped obstruction channel 31, the width of the upper first downward obstruction channel 32 and the upper first upward obstruction channel 33 are all 20μm, the width of the upper intermediate transition section 35 is 40μm, and the width of the inlet end of the upper outlet section 39 is 30μm.

[0051] The lower Tesla trench 4 has a trench depth of 4.5μm-90μm, the inlet end width of the lower inlet section 44 is 150μm, the width of the intersection of the lower second obstruction channel 41 and the lower first upward obstruction channel 43, and the width of the intersection of the lower second obstruction channel 47 and the lower second downward obstruction channel 46 are the same, all widened to 500μm, the width of the lower second obstruction channel 41, the lower first downward obstruction channel 42 and the lower first upward obstruction channel 43 are all 100μm, the width of the lower intermediate transition section 45 is 200μm, and the outlet end width of the lower outlet section 49 is 150μm.

[0052] The preferred material for the disc body 1 in Example 2 is polyurethane.

Claims

1. A composite grinding and polishing structure design for wafer-level grinding and polishing processes, characterized in that, The device includes a disk body (1), with a positioning groove (2) at the center of its upper end. On the disk body (1) surrounding the positioning groove (2), there are upper Tesla grooves (3), lower Tesla grooves (4), and an annular channel (5). The upper Tesla grooves (3) and lower Tesla grooves (4) are arranged in a circumferentially spaced array along the disk body (1) and extend radially. The upper Tesla grooves (3) and lower Tesla grooves (4) are spaced vertically and circumferentially adjacent. The inner ends of the upper Tesla grooves (3) and lower Tesla grooves (4) penetrate the positioning groove (2), and their outer ends penetrate the outer circumferential surface of the disk body (1). The annular channel (5) is a sloping structure. The structure consists of sequentially spaced rings along the radial direction of the disc (1), all of which penetrate the upper Tesla groove (3) and the lower Tesla groove (4), forming a layered fluid passage. The wear debris is carried by the polishing fluid flow, flows into the annular channel through the upper Tesla groove, and sinks to the lower Tesla groove. The upper Tesla groove (3) includes several series-connected upper micro Tesla valve units for guiding the forward flow of the polishing fluid, and the lower Tesla groove (4) includes several series-connected lower micro Tesla valve units for reverse flow resistance. The groove depth of the upper Tesla groove (3) or the lower Tesla groove (4) increases nonlinearly from the center to the outer periphery along the radial direction of the disc (1), and the nonlinear increasing function is: ； Where H0 is the initial depth of the upper Tesla trench (3) or the lower Tesla trench (4), k is the trench depth compensation coefficient, and R max r is the maximum radius of the disk body (1), and r is the groove depth. The radius at point n is a nonlinear exponent, where n ≥ 2.

2. The composite grinding and polishing structure design for wafer-level grinding and polishing processes according to claim 1, characterized in that, The upper Tesla trench (3) also includes an upper starting section trench and an upper tail section trench. The upper starting section trench and the upper tail section trench are straight. An upper middle section trench is connected in series between the upper starting section trench and the upper tail section trench. The upper middle section trench is a number of upper micro Tesla valve units connected in series.

3. The composite grinding and polishing structure design for wafer-level grinding and polishing processes according to claim 2, characterized in that, The lower Tesla trench (4) also includes a lower starting section trench and a lower tail section trench. Both the lower starting section trench and the lower tail section trench are straight. A lower middle section trench is connected in series between the lower starting section trench and the lower tail section trench. The lower middle section trench is a number of lower micro Tesla valve units connected in series.

4. The composite grinding and polishing structure design for wafer-level grinding and polishing processes according to claim 3, characterized in that, The upper micro Tesla valve unit includes an upper first Tesla flow channel and an upper second Tesla flow channel, which are connected in series in opposite directions.

5. The composite grinding and polishing structure design for wafer-level grinding and polishing processes according to claim 4, characterized in that, The upper first Tesla flow channel includes an upper inlet section (34), an upper first wing-shaped obstruction flow channel (31), an upper first downward obstruction flow channel (32), and an upper first upward obstruction flow channel (33). One end of the upper first wing-shaped obstruction flow channel (31) is connected to one end of the upper first upward obstruction flow channel (33) and then connected to the upper inlet section (34). The other end of the upper first wing-shaped obstruction flow channel (31) is connected to one end of the upper first downward obstruction flow channel (32). The other end of the upper first downward obstruction flow channel (32) and the other end of the upper first upward obstruction flow channel (33) are connected to an upper intermediate transition section (35). The upper second Tesla flow channel includes an upper outlet section (39), an upper second wing-shaped obstruction flow channel (37), and an upper second downward obstruction flow channel (36). The upper second wing-shaped obstruction channel (37) and the upper second wing-shaped obstruction channel (38) are connected to the upper middle transition section (35) after one end of the upper second wing-shaped obstruction channel (37) is connected to one end of the upper second wing-shaped obstruction channel (38), and the upper second wing-shaped obstruction channel (36) and the upper second wing-shaped obstruction channel (38) are connected to the upper outlet section (39) after the other end of the upper second wing-shaped obstruction channel (31) and the upper second wing-shaped obstruction channel (37) are both arc-shaped channels, and the upper first wing-shaped obstruction channel (32), the upper first wing-shaped obstruction channel (33), the upper second wing-shaped obstruction channel (36) and the upper second wing-shaped obstruction channel (38) are all straight channels.

6. The composite grinding and polishing structure design for wafer-level grinding and polishing processes according to claim 4, characterized in that, The lower miniature Tesla valve unit includes a lower first Tesla flow channel and a lower second Tesla flow channel, which are connected in series in opposite directions.

7. The composite grinding and polishing structure design for wafer-level grinding and polishing processes according to claim 6, characterized in that, The lower first Tesla flow channel includes a lower inlet section (44), a lower first obstruction flow channel (41), a lower first downward inclined flow channel (42), and a lower first upward inclined flow channel (43). One end of the lower first obstruction flow channel (41) is connected to one end of the lower first upward inclined flow channel (43) and then connected to the lower inlet section (44). The other end of the lower first obstruction flow channel (41) is connected to one end of the lower first downward inclined flow channel (42). The other end of the lower first downward inclined flow channel (42) is connected to the other end of the lower first upward inclined flow channel (43) and then connected to a lower intermediate transition section (45). The lower second Tesla flow channel includes a lower outlet section (49), a lower second obstruction flow channel (47), a lower second downward inclined flow channel (46), and a lower second upward inclined flow channel (43). The flow channel (48) is connected to the lower intermediate transition section (45) after one end of the lower second obstruction flow channel (47) is connected to one end of the lower second downward obstruction flow channel (46). The other end of the lower second obstruction flow channel (47) is connected to one end of the lower second upward obstruction flow channel (48). The other end of the lower second downward obstruction flow channel (46) and the other end of the lower second upward obstruction flow channel (48) are connected to the lower outlet section (49). The lower first obstruction flow channel (41), the lower first downward obstruction flow channel (42) and the lower first upward obstruction flow channel (43) are connected in series to form a first triangular flow channel. The lower second obstruction flow channel (47), the lower second downward obstruction flow channel (46) and the lower second upward obstruction flow channel (48) are connected in series to form a second triangular flow channel.

8. A polishing method for wafer-level polishing processes, employing a composite polishing structure design for wafer-level polishing processes as described in any one of claims 1-7, characterized in that, The method includes the following steps: Step S1: Fix the wafer to be processed onto the disk (1); Step S2: Connect the polishing fluid to the positioning groove (2) of the disc body; Step S3: Start the rotation of the disk body (1). The polishing fluid flows in the forward direction along the upper Tesla groove (3) under the action of centrifugal force and acts between the disk body (1) and the wafer. The polishing waste generated by polishing settles into the lower Tesla groove (4) through the annular channel (5) and is unidirectionally discharged to the outside of the disk body (1).

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