Method for preparing honeycomb porous wafer thinning grinding wheel based on in-situ gel casting method

Abstract

The invention discloses a method for preparing a honeycomb porous wafer thinned grinding wheel based on an in-situ gel casting method, which comprises the following steps of: placing superfine diamond micro-powder in an acidic strong oxidizing solution, heating, centrifugally cleaning until the superfine diamond micro-powder is neutral, and drying to obtain pre-oxidized diamond micro-powder; adding the modified diamond micro-powder into a silane coupling agent solution for grafting reaction to obtain modified diamond micro-powder; the method comprises the following steps: dissolving an organic monomer and a cross-linking agent in deionized water according to a predetermined mass ratio, and stirring to obtain an organic monomer premixed solution; adding microcrystalline glass binder powder, a polymeric dispersant and modified diamond micro-powder into the organic monomer premixed liquid, and carrying out dispersion treatment to obtain high-solid-content ceramic slurry; adding a macroporous pore-forming agent into the ceramic slurry, stirring, fully discharging bubbles, adding an initiator and a catalyst, pouring into a forming mold, carrying out in-situ polymerization reaction on organic monomers to form a gel network, and further forming a wet blank; and the wet blank is dried, degummed and sintered to obtain the grinding wheel block with the honeycomb structure. And cutting the honeycomb-structure grinding wheel blocks, and pasting the honeycomb-structure grinding wheel blocks in the grooves of the grinding wheel base body in an array manner to form the honeycomb porous wafer thinning grinding wheel. The problem of agglomeration of the ultrafine diamond powder is solved, and the bending strength of the prepared grinding wheel can be improved while the high porosity is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision grinding technology, and in particular to a method for preparing honeycomb porous wafer thinning grinding wheels based on in-situ gel casting. Background Technology

[0003] Currently, the bonding agents used in industrial diamond grinding wheels mainly include three categories: resin, metal, and ceramic (glass-ceramic). Among them, ceramic (glass-ceramic) bonded diamond grinding wheels are widely recognized as the most suitable tools for ultra-precision grinding and thinning of hard and brittle semiconductor wafers due to their high elastic modulus, excellent chemical stability, ease of dressing, and unique porous structure. However, in the preparation of ultra-fine particle size, high porosity ceramic-bonded diamond grinding wheels for ultra-precision thinning of SiC semiconductor wafers, existing preparation technologies (such as powder dry pressing + solid-state sintering) face insurmountable technical bottlenecks, specifically in the following aspects: 1) The problem of agglomeration of ultrafine diamond powder is difficult to solve: Ultrafine diamond powder has a large specific surface area and high surface energy, and it is very easy to agglomerate during the traditional dry mixing and pressing process. This leads to uneven microstructure of the grinding wheel. This unevenness will form abnormally large particles during grinding, resulting in scratches or deep pits on the wafer surface, which seriously affects the surface quality.

[0004] 2) Difficulty in constructing a uniform and interconnected pore structure: For ultrafine diamond grinding wheels, due to the extremely fine grinding debris that easily clogs pores, it is necessary to construct an interconnected pore network with high porosity and suitable pore size to accommodate grinding debris and transport coolant. Existing technologies mostly use solid pore-forming agents. These solid pore-forming agents are difficult to disperse uniformly in ultrafine powders during the mixing process. After sintering, they easily form localized large pores or dense layers, resulting in unstable grinding performance and poor pore connectivity. Consequently, coolant cannot easily enter the grinding zone, leading to grinding heat accumulation and easily causing wafer burn-out.

[0005] 3) The contradiction between "high porosity" and "high strength": Pursuing high porosity (>50%) to improve chip-holding capacity often requires adding a large amount of pore-forming agent, which severely damages the bond bridge, leading to a sharp decrease in the mechanical strength of the grinding wheel. Under high-speed grinding conditions (linear speed >30 m / s), low-strength porous grinding wheels are prone to breakage or chipping, posing a serious safety hazard.

[0006] 4) Poor density gradient and structural uniformity: Traditional molding processes rely on external force to compact powder. Due to the internal friction between powder particles, a density gradient (high density on the upper and lower surfaces and low density in the core) is inevitably generated during the pressing process. This effect is particularly significant for ultrafine powders. The density gradient will cause inconsistent sintering shrinkage of the grinding wheel, generating internal stress and even cracking. It will also cause inconsistent wear rates in different parts of the grinding wheel, which will seriously affect the surface accuracy (TTV) and grinding stability when grinding large-size wafers, and easily lead to defects such as "center pit".

[0007] Therefore, overcoming the problem of ultrafine powder agglomeration and constructing a microstructure with uniform composition, high porosity, and good pore connectivity under the premise of low-temperature sintering and ensuring that the grinding wheel has a certain strength is a key technical problem that urgently needs to be solved in the preparation of high-performance silicon carbide wafer thinning grinding wheels.

[0008] Therefore, it is necessary to provide a method for preparing honeycomb porous wafer thinning grinding wheels based on in-situ gel casting to solve the above-mentioned technical problems. Summary of the Invention

[0009] This invention provides a method for preparing honeycomb porous wafer thinning grinding wheels based on in-situ gel casting method, in order to solve or at least alleviate the problems mentioned above.

[0010] According to one aspect of the present invention, a method for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting is provided, comprising: placing ultrafine diamond powder in an acidic, strongly oxidizing solution for heating treatment to remove impurities on the surface of the ultrafine diamond powder and introduce oxygen-containing active functional groups on the surface of the ultrafine diamond powder; centrifuging and washing the heated ultrafine diamond powder until neutral and then drying it to obtain pre-oxidized diamond powder; adding the pre-oxidized diamond powder to a silane coupling agent solution for grafting reaction, and after the reaction is completed, centrifuging, washing with ethanol, and drying treatment to obtain modified diamond powder with surface-grafted hydrophilic groups; dissolving an organic monomer and a crosslinking agent in deionized water at a predetermined mass ratio and stirring until completely dissolved to obtain an organic monomer premix; Microcrystalline glass binder powder, polymeric dispersant, and modified diamond micropowder are sequentially added to the organic monomer premix, and dispersed to obtain a ceramic slurry with a solid content greater than a solid content threshold. A macroporous pore-forming agent is added to the ceramic slurry and stirred to obtain a premixed ceramic slurry. After thorough defoaming of the premixed ceramic slurry, an initiator and catalyst are added, and the slurry is poured into a molding die to allow the organic monomers in the premixed ceramic slurry to undergo in-situ polymerization at a predetermined polymerization temperature. A three-dimensional polymer gel network is formed, in which the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent are frozen and locked in situ to form a wet blank. The wet blank is dried, debinded, and sintered to allow the microcrystalline glass binder powder to melt and wet the modified diamond micropowder and precipitate a microcrystalline phase, resulting in a honeycomb structure grinding wheel block. The honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments, and multiple honeycomb structure arc-shaped segments are arrayed and pasted into the grooves of the grinding wheel substrate to form a honeycomb porous wafer thinning grinding wheel.

[0011] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, microcrystalline glass binder powder and polymeric dispersant, as well as the modified diamond micro powder, are sequentially added to the organic monomer premix, and dispersed to obtain a ceramic slurry with a solid content greater than the solid content threshold. This includes: sequentially adding microcrystalline glass binder powder and polymeric dispersant, as well as the modified diamond micro powder, to the organic monomer premix to obtain an initial slurry; adjusting the initial slurry to alkalinity and then ball milling or ultrasonically dispersing it to obtain a ceramic slurry with a solid content greater than the solid content threshold.

[0012] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, microcrystalline glass binder powder and polymeric dispersant, as well as the modified diamond micro powder, are sequentially added to the organic monomer premix, and dispersed to obtain a ceramic slurry with a solid content greater than the solid content threshold. This includes: first adding microcrystalline glass binder powder and polymeric dispersant to the organic monomer premix, then shearing and dispersing it for 10 minutes using a high-speed shear homogenizer at a predetermined shear speed, then adding the modified diamond micro powder, and then shearing and dispersing it for 40-60 minutes using the high-speed shear homogenizer at the predetermined shear speed to obtain a ceramic slurry with a solid content greater than the solid content threshold.

[0013] Optionally, in the method for preparing honeycomb porous wafer thinning grinding wheels based on the in-situ gel casting method according to the present invention, the total mass percentage of the microcrystalline glass binder powder, modified diamond micro powder, and macroporous pore-forming agent added to the organic monomer premixed liquid is 1, wherein the mass percentage of the microcrystalline glass binder powder is 15-20%, the mass percentage of the modified diamond micro powder is 55-65%, and the mass percentage of the macroporous pore-forming agent is 20-30%.

[0014] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, the wet blank is dried, debinded, and sintered to melt and wet the modified diamond micropowder with the glass-ceramic binder powder and precipitate the microcrystalline phase to obtain a honeycomb structure grinding wheel block. This includes: drying the wet blank in a vacuum drying oven so that the three-dimensional polymer gel network loses water and shrinks to form interconnected microporous channels, and obtaining a microporous structure dried blank; sintering the microporous structure dried blank based on a segmented heating curve including a low temperature stage and a high temperature stage, so that the microporous structure dried blank removes organic matter and polymer network in the low temperature stage, and melts and wets the modified diamond micropowder with the glass-ceramic binder powder and precipitates the microcrystalline phase in the high temperature stage to obtain a honeycomb structure grinding wheel block.

[0015] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, the low-temperature stage includes: heating from 0°C to 400°C at a heating rate of 1-2°C / min, wherein the temperature is held at 300°C and 400°C for 120-180 min respectively; the high-temperature stage includes: heating from 400°C to the sintering temperature at a heating rate of 3-5°C / min, and holding at the sintering temperature for 2-3 h, wherein the sintering temperature is 550-650°C.

[0016] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, the pre-oxidized diamond micro powder is added to a silane coupling agent solution for a grafting reaction, comprising: adding the pre-oxidized diamond micro powder to a silane coupling agent solution for a grafting reaction, wherein the mixture is stirred at 40-80°C for 4-6 hours until the grafting reaction is completed.

[0017] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, the honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments, and a plurality of the honeycomb structure arc-shaped segments are attached in the grooves of the grinding wheel substrate to form a honeycomb porous wafer thinning grinding wheel. This includes: cutting the honeycomb structure grinding wheel block into corresponding honeycomb structure arc-shaped segments using a diamond wire cutter; attaching a plurality of the honeycomb structure arc-shaped segments in the grooves of the grinding wheel substrate at predetermined intervals; and performing finishing and dynamic balancing after curing to obtain a honeycomb porous wafer thinning grinding wheel.

[0018] Optionally, in the method for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method according to the present invention, the organic monomer is acrylamide or methacrylamide, the crosslinking agent is N,N'-methylenebisacrylamide, and the predetermined mass ratio is 6:1 to 30:1.

[0019] Optionally, in the method for preparing honeycomb porous wafer thinning grinding wheels based on the in-situ gel casting method according to the present invention, the acidic strong oxidant solution is a potassium permanganate solution or a hydrogen peroxide solution; the oxygen-containing active functional group includes hydroxyl and carboxyl groups; the silane coupling agent solution is a pre-prepared 1-5% hydrolyzed silane coupling agent solution, and the silane coupling agent solution is any one of KH550, KH560, and KH570; the polymeric dispersant is ammonium polyacrylate dispersant or polyvinylpyrrolidone dispersant; the initiator is ammonium persulfate; and the catalyst is tetramethylethylenediamine.

[0020] According to the technical solution of the present invention, a method for preparing honeycomb porous wafer thinning grinding wheels based on in-situ gel casting is provided. Ultrafine diamond powder is placed in an acidic, strongly oxidizing solution for heating treatment, then centrifuged, washed until neutral, and dried to obtain pre-oxidized diamond powder. The pre-oxidized diamond powder is added to a silane coupling agent solution for grafting reaction, and after centrifugation, ethanol washing, and drying, modified diamond powder with surface-grafted hydrophilic groups is obtained. An organic monomer premix is ​​obtained by dissolving an organic monomer and a crosslinking agent in deionized water at a predetermined mass ratio and stirring until completely dissolved. Next, microcrystalline glass binder powder, polymeric dispersant, and modified diamond micropowder are sequentially added to the organic monomer premix, and dispersed to obtain a high-solids-content ceramic slurry. Then, a macroporous pore-forming agent is added to the ceramic slurry and stirred to obtain a premixed ceramic slurry. After thorough degassing of the premixed ceramic slurry, an initiator and catalyst are added and poured into a molding die. This allows the organic monomers to undergo in-situ polymerization at a predetermined polymerization temperature, forming a three-dimensional polymeric gel network. This allows the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent to be frozen and locked in situ, forming a wet blank. The wet blank is then dried, debinded, and sintered to allow the microcrystalline glass binder powder to melt and wet the modified diamond micropowder, precipitating a microcrystalline phase, resulting in a honeycomb structure grinding wheel block. Finally, the honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments and arrayed and pasted into the grooves of the grinding wheel substrate to form a honeycomb porous wafer thinning grinding wheel.

[0021] Based on this, the present invention overcomes the problem of agglomeration of ultrafine diamond powder by combining surface hydrophilic modification with liquid phase in-situ curing technology. On the other hand, the rapid in-situ curing of the gel network can freeze the dispersed state instantly, ensuring that the modified diamond powder and pores are evenly distributed in the grinding wheel structure, thereby avoiding scratches caused by local enrichment of the grinding wheel during the wafer thinning process.

[0022] Secondly, the honeycomb structure grinding wheel block prepared according to the present invention has spherical macropores left by the burn-off of the macropore-forming agent. These macropores are large and regular in size, providing ample chip space for the grinding wheel to thin the wafer. Simultaneously, it has micropores formed by the shrinkage of the gel network during drying. These micropores can connect with the isolated macropores to form a three-dimensional, interconnected coolant delivery channel. This dual-pore honeycomb structure ensures excellent heat dissipation and chip removal capabilities while avoiding structural breakage caused by traditional macropore-forming agents. It can significantly reduce the grinding temperature during the grinding wheel's thinning process, preventing wafer burn-out.

[0023] Furthermore, the wet blank formed by the gel casting process has a uniform microstructure, and the microcrystalline glass binder improves the intrinsic strength of the glass through the microcrystalline toughening mechanism during sintering. This allows the final grinding wheel to maintain high porosity while improving bending strength, thus meeting the safety requirements of high-speed ultra-precision grinding.

[0024] Furthermore, the honeycomb porous wafer thinning grinding wheel finally prepared according to the present invention has a uniform structure, good self-sharpening properties and stable grinding force. When using this grinding wheel to grind and thin large-size silicon carbide wafers, it can effectively suppress grinding vibration and central pit defects, and achieve efficient and low-damage mirror thinning.

[0025] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0026] To achieve the foregoing and related objectives, certain illustrative aspects are described herein in conjunction with the following description and accompanying drawings. These aspects indicate various ways in which the principles disclosed herein may be practiced, and all aspects and their equivalents are intended to fall within the scope of the claimed subject matter. The foregoing and other objectives, features, and advantages of this disclosure will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings. Throughout this disclosure, the same reference numerals generally refer to the same parts or elements.

[0027] Figure 1 A schematic flowchart of a method 100 for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting method according to an embodiment of the present invention is shown. Figure 2 An exemplary schematic diagram of the process flow for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting method according to some embodiments of the present invention is shown. Figure 3 A schematic diagram of the microstructure of a honeycomb porous wafer thinning grinding wheel prepared according to an embodiment of the present invention is shown; Figure 4 The diagram shows the TTV and surface roughness results of the honeycomb porous wafers prepared by the in-situ gel casting method in the embodiment of the present invention and the dry pressing method in the comparative embodiment after grinding tests with thinning grinding wheels. Detailed Implementation

[0028] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0029] To address the problems of severe agglomeration of ultrafine diamond powder, uneven pore structure distribution and poor connectivity, and significant reduction in mechanical strength due to high porosity in existing technologies for preparing ultrafine diamond grinding wheels with high particle size and high porosity, this invention provides a method for preparing honeycomb porous wafer-thinned grinding wheels based on in-situ gel casting. By modifying the surface of ultrafine diamond micropowder with hydrophilicity, the problem of ultrafine diamond powder agglomeration is solved. By employing a synergistic pore-forming strategy of pore-forming agent decomposition and gel network shrinkage, combined with in-situ gel casting molding process, it is possible to construct a high-porosity diamond grinding wheel with uniform composition and hierarchical interconnected honeycomb pore structure while ensuring the high strength of the grinding wheel, significantly improving the self-sharpening property and grinding stability of the grinding wheel.

[0030] The following is a detailed description of the method 100 for preparing honeycomb porous wafer thinning grinding wheels based on in-situ gel casting method according to the present invention.

[0031] Figure 1 A schematic flowchart of a method 100 for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting according to an embodiment of the present invention is shown. Figure 2 An exemplary schematic diagram of the process flow for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting method according to some embodiments of the present invention is shown.

[0032] It should be noted that the honeycomb porous wafer thinning grinding wheel prepared in the embodiments of the present invention is specifically an ultrafine-grained diamond grinding wheel based on a microcrystalline glass binder (ceramic binder) used for ultra-precision thinning of silicon carbide semiconductor wafers. It should also be noted that in the embodiments of the present invention, the ultrafine particle size is specifically W0-1μm.

[0033] like Figure 1 As shown, the method 100 for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting includes the following steps 110-170.

[0034] Step 110: The ultrafine diamond powder (WO-1μm diamond powder) is placed in an acidic, strongly oxidizing solution and heated to remove surface impurities and introduce oxygen-containing active functional groups onto the surface. Subsequently, the heated ultrafine diamond powder is centrifuged, washed until neutral, and then dried to obtain pre-oxidized diamond powder. Here, the oxygen-containing active functional groups include hydroxyl (-OH) and carboxyl (-COOH) groups.

[0035] In some embodiments, the strong acidic oxidant solution may be a potassium permanganate solution or a hydrogen peroxide solution.

[0036] In some embodiments, in step 110, after placing the ultrafine diamond powder (WO-1μm diamond powder) in an acidic, strongly oxidizing solution, its pH value is first adjusted using a pH adjuster, for example, to pH 4.5. The pH adjuster can be acetic acid or tetramethylammonium hydroxide. Then, a heat treatment is performed (e.g., at 60°C for 2 hours) to remove surface impurities and introduce oxygen-containing active functional groups onto the surface of the ultrafine diamond powder. Afterward, the heat-treated ultrafine diamond powder is centrifuged and washed until neutral, and then dried (e.g., at 100°C for 6 hours) to obtain pre-oxidized diamond powder.

[0037] Subsequently, a 1-5% hydrolyzed silane coupling agent solution can be prepared in advance. Then, step 120 is performed. In some embodiments, the silane coupling agent solution can be any one of KH550, KH560, and KH570.

[0038] Step 120: The pre-oxidized diamond micropowder obtained in step 110 is added to a silane coupling agent solution (i.e., a pre-prepared hydrolyzed 1-5% silane coupling agent solution) to carry out a grafting reaction. After the reaction is completed, the powder is centrifuged, washed with ethanol, and dried to obtain modified diamond micropowder with surface-grafted hydrophilic groups. This allows for the surface hydrophilic modification of ultrafine diamond micropowder.

[0039] It should be noted that during the grafting reaction, the silanol groups at one end of the silane coupling agent undergo a condensation reaction with the hydroxyl groups on the surface of the pre-oxidized diamond micropowder, while the hydrophilic groups at the other end extend into the silane coupling agent solution. This significantly improves the dispersion stability and wettability of the ultrafine diamond micropowder in the water-based system. After the reaction is completed, the diamond micropowder with surface-grafted hydrophilic groups can be obtained through centrifugation, ethanol washing, and drying, thus achieving the surface hydrophilic modification of the ultrafine diamond micropowder.

[0040] In some embodiments, in step 120, pre-oxidized diamond micropowder can be added to a silane coupling agent solution for a grafting reaction, wherein the mixture can be stirred at 40-80°C for 4-6 hours until the grafting reaction is complete. After the grafting reaction is complete, the mixture can be centrifuged, washed with ethanol, and dried to obtain modified diamond micropowder with hydrophilic groups grafted onto its surface.

[0041] Step 130: Dissolve the organic monomer and crosslinking agent in deionized water at a predetermined mass ratio and stir until completely dissolved to obtain an organic monomer premix.

[0042] It should be noted that the mass ratio of organic monomers to crosslinking agents directly affects the crosslinking density and shrinkage rate of the gel network, thereby adjusting the microporous structure.

[0043] In some embodiments, the predetermined mass ratio of the organic monomer to the crosslinking agent can be 6:1 to 30:1. The present invention does not limit the specific value of the predetermined mass ratio.

[0044] In some embodiments, the organic monomer may be acrylamide (AM) or methacrylamide (MAM). The crosslinking agent may be N,N'-methylenebisacrylamide (MBAM). That is, in step 130, acrylamide (AM) and N,N'-methylenebisacrylamide (MBAM) may be dissolved in deionized water at a predetermined mass ratio and stirred until completely dissolved to obtain an organic monomer premix. Alternatively, methacrylamide (MAM) and N,N'-methylenebisacrylamide (MBAM) may be dissolved in deionized water at a predetermined mass ratio and stirred until completely dissolved to obtain an organic monomer premix.

[0045] Step 140: Add microcrystalline glass binder powder (specifically low-temperature high-strength microcrystalline glass binder powder) and polymeric dispersant, as well as modified diamond micro powder (modified diamond micro powder obtained in step 120) sequentially to the organic monomer premix liquid obtained in step 130, and after dispersion treatment, a ceramic slurry with high solid content can be obtained, specifically a ceramic slurry with a solid content greater than the solid content threshold.

[0046] It should be noted that solid content refers to the percentage of the mass of solids (powders) in the ceramic slurry relative to the total mass of the ceramic slurry.

[0047] The solid content threshold can be 50%. That is, after performing step 140, a ceramic slurry with a solid content greater than 50% can be obtained.

[0048] In some embodiments, in step 140, microcrystalline glass binder powder, polymeric dispersant, and modified diamond micropowder are sequentially added to the organic monomer premix to obtain an initial slurry. Subsequently, the initial slurry can be adjusted to alkaline conditions and then ball-milled or ultrasonically dispersed to obtain a ceramic slurry with a solid content greater than the solid content threshold. For example, the pH of the initial slurry can be adjusted to pH 9-11 using a pH adjuster tetramethylammonium hydroxide (TMAH) to make it alkaline. In this way, based on the synergistic effect of electrostatic repulsion and steric hindrance, a low-viscosity, high-solid-content (solid content greater than 50%) and uniformly dispersed ceramic slurry can be prepared after ball milling or ultrasonic dispersion.

[0049] In some embodiments, a high-speed shear homogenizer can also be used for dispersion treatment in step 140. Specifically, the organic monomer premix obtained in step 130 can be placed in a beaker beforehand, and the shear speed of the high-speed shear homogenizer can be adjusted to a predetermined shear speed, which can be 3000-10000 rpm. In step 140, microcrystalline glass binder powder and polymeric dispersant can be added to the organic monomer premix first, and then sheared and dispersed for 10 minutes using a high-speed shear homogenizer at the predetermined shear speed (3000-10000 rpm). Then, modified diamond micropowder is added, and then sheared and dispersed for 40-60 minutes using a high-speed shear homogenizer at the predetermined shear speed to obtain a ceramic slurry with a solid content greater than the solid content threshold (solid content greater than 50%) and uniform dispersion.

[0050] In some embodiments, the polymeric dispersant may specifically be ammonium polyacrylate dispersant or polyvinylpyrrolidone dispersant.

[0051] Step 150: Add macroporous pore-forming agent (microspheres) to the ceramic slurry obtained in step 140 and stir (e.g., stir for 30 minutes) to obtain a premixed ceramic slurry. Then, after fully defoaming the premixed ceramic slurry, add an initiator (ammonium persulfate APS) and a catalyst (tetramethylethylenediamine TEMED) and quickly pour it into a molding mold so that the organic monomers in the premixed ceramic slurry undergo in-situ polymerization at a predetermined polymerization temperature to form a three-dimensional polymer gel network. The three-dimensional polymer gel network can freeze and lock the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent in situ to form a wet blank with a certain strength.

[0052] Therefore, by combining surface hydrophilic modification with liquid phase in-situ curing technology, on the one hand, the agglomeration problem caused by the high surface energy of ultrafine diamond powder in the traditional dry pressing process is overcome; on the other hand, the rapid in-situ curing of the gel network can instantly "freeze" the dispersed state, ensuring that the modified diamond powder and pores are evenly distributed in the grinding wheel structure, thereby avoiding scratches caused by local enrichment of the grinding wheel during the wafer thinning process.

[0053] In some embodiments, in steps 140-150 above, the total mass percentage of the microcrystalline glass binder powder, modified diamond micro powder, and macroporous pore-forming agent added to the organic monomer premix liquid is 1, wherein the mass percentage of the microcrystalline glass binder powder is 15-20%, the mass percentage of the modified diamond micro powder is 55-65%, and the mass percentage of the macroporous pore-forming agent is 20-30%.

[0054] It should be noted that before performing step 140, the following can be calculated and weighed in advance according to the solid content requirements of the ceramic slurry (e.g., 50-70%): 15-20% by mass of microcrystalline glass binder powder, 55-65% by mass of modified diamond micro powder, and 20-30% by mass of macroporous pore-forming agent. This will allow the corresponding masses of microcrystalline glass binder powder, modified diamond micro powder, and macroporous pore-forming agent to be added in steps 140 and 150, respectively.

[0055] In some embodiments, the macroporous pore-forming agent (microspheres) may specifically be PMMA microspheres or PS microspheres.

[0056] In some embodiments, the predetermined polymerization temperature in step 150 may specifically be 40-60°C.

[0057] Step 160: The wet blank (after demolding) formed in step 150 is dried (drying under controlled humidity conditions), debinded, and sintered to melt and wet the modified diamond micropowder with the microcrystalline glass binder powder and precipitate the microcrystalline phase, resulting in a honeycomb structure grinding wheel block. Thus, the honeycomb structure grinding wheel block prepared according to this invention has dual porosity characteristics of macropores and shrinking micropores in the gel network. Specifically, the honeycomb structure grinding wheel block prepared according to this invention has spherical macropores left by the burn-off of the macropore-forming agent, with large and regular pore diameters, providing sufficient chip space for the grinding wheel to thin the wafer during grinding; simultaneously, it has micropores (connecting micropore channels) formed by the shrinkage of the gel network during drying, which can connect isolated macropores to form a three-dimensional interconnected coolant transport channel. This dual-porosity honeycomb structure ensures excellent heat dissipation and chip removal capabilities while avoiding structural breakage caused by traditional pore-forming agents, significantly reducing grinding temperature and preventing wafer burn-out during the grinding wheel's thinning process.

[0058] In some embodiments, in step 160, the wet blank is first dried (vacuum dried) by placing it in a vacuum drying oven and drying it there so that the three-dimensional polymer gel network loses water and shrinks, thereby forming interconnected microporous channels (micron-level interconnected microporous channels) between the particles, thus obtaining a microporous structured dried blank. Specifically, during the drying process of the wet blank in the vacuum drying oven, it can first be dried at a drying temperature of 45°C for 12-18 hours, and then the drying temperature can be increased to 100°C, and then the wet blank can be dried to constant weight at a drying temperature of 100°C.

[0059] Subsequently, the microporous structure dried blank can be debinded and sintered in the following way: The microporous structure dried blank is placed in a high-temperature sintering furnace. In the high-temperature sintering furnace, the microporous structure dried blank is sintered based on a segmented heating curve that includes low-temperature and high-temperature stages. This allows the microporous structure dried blank to expel organic matter and polymer networks in the low-temperature stage (debinding), and in the high-temperature stage, the microcrystalline glass binder powder melts and wets the modified diamond micro powder and precipitates the microcrystalline phase (reinforcing microcrystals). After sintering, the blank is cooled to room temperature with the high-temperature sintering furnace, thereby obtaining a honeycomb structure grinding wheel block.

[0060] In some embodiments, the low-temperature stage of the segmented heating curve is as follows: the temperature is increased from 0°C to 400°C at a heating rate of 1-2°C / min, wherein the temperature is held at 300°C and 400°C for 120-180min respectively, which ensures that various organic substances and pore-forming agents are fully decomposed.

[0061] The high-temperature stage of the segmented heating curve is as follows: After holding at 400℃, the temperature is increased from 400℃ to the sintering temperature at a rate of 3-5℃ / min, and held at the sintering temperature for 2-3 hours, where the sintering temperature can be 550-650℃. It should be noted that the sintering process ends after holding at the sintering temperature for 2-3 hours, and the material is then cooled to room temperature with the furnace to obtain a honeycomb structure grinding wheel block.

[0062] It should be understood that the specific process of sintering the microporous structure dry green body in a high-temperature sintering furnace based on a segmented heating curve including low-temperature and high-temperature stages is as follows: The temperature is increased from 0℃ to 400℃ at a heating rate of 1-2℃ / min, with holding times at 300℃ and 400℃ for 120-180 min respectively. This low-temperature sintering process ensures the complete decomposition of various organic substances and pore-forming agents, allowing the microporous structure dry green body to expel organic matter and polymer networks. After holding at 400℃, the temperature is increased from 400℃ to the sintering temperature (550-650℃) at a heating rate of 3-5℃ / min, and held at the sintering temperature for 2-3 hours. This allows the glass binder powder to melt and wet the modified diamond micropowder, precipitating a microcrystalline phase (reinforcing microcrystals). The furnace is then cooled to room temperature to obtain a honeycomb structure grinding wheel block.

[0063] Step 170: Cut the honeycomb structure grinding wheel block obtained in step 160 into corresponding honeycomb structure arc-shaped segments. Then, by attaching multiple honeycomb structure arc-shaped segments in an array to the grooves of the grinding wheel substrate, a honeycomb porous wafer thinning grinding wheel can be formed.

[0064] In some embodiments, the honeycomb structure grinding wheel block can be cut into corresponding honeycomb structure arc-shaped segments using a diamond wire cutter. Then, multiple honeycomb structure arc-shaped segments can be arrayed and adhered to the grooves of the grinding wheel substrate at predetermined intervals. The honeycomb structure arc-shaped segments adhered to the grooves of the grinding wheel substrate are then cured, for example, using high-strength epoxy resin adhesive. After curing, finishing (outer circle finishing and end face finishing) is performed, followed by dynamic balancing (dynamic balancing must meet G0.4-G1.0 standards) to obtain a honeycomb porous wafer thinning grinding wheel. Specifically, 30-35 honeycomb structure arc-shaped segments can be arrayed and adhered to the grooves of the grinding wheel substrate.

[0065] Figure 3 A schematic diagram of the microstructure of a honeycomb porous wafer thinning grinding wheel prepared according to an embodiment of the present invention is shown.

[0066] The following three specific embodiments (the first embodiment, the second embodiment, and the third embodiment) will be used to describe in detail the process parameters involved in the method for preparing honeycomb porous wafer thinning grinding wheels based on in-situ gel casting.

[0067] In the first embodiment, the process of the method 100 for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method is as follows: In step 110, ultrafine diamond powder (W 0.5 μm diamond powder) is placed in a 30% hydrogen peroxide solution, and the pH value is adjusted to pH 4.5 using acetic acid solution as a pH adjuster. Then, it is heated at 60°C for 2 hours to remove impurities from the surface of the ultrafine diamond powder and introduce oxygen-containing active functional groups such as hydroxyl (-OH) and carboxyl (-COOH) groups onto the surface of the ultrafine diamond powder. Subsequently, the heat-treated ultrafine diamond powder is centrifuged and washed until neutral, and then dried at 100°C for 6 hours to obtain pre-oxidized diamond powder.

[0068] Subsequently, a 3% KH550 silane coupling agent solution after hydrolysis can be prepared in advance.

[0069] Next, in step 120, the pre-oxidized diamond powder obtained in step 110 is added to the prepared 3% KH550 silane coupling agent solution for a grafting reaction. The mixture is stirred at 60°C for 6 hours until the grafting reaction is complete. During the grafting reaction, the silanol groups at one end of the silane coupling agent undergo a condensation reaction with the hydroxyl groups on the surface of the pre-oxidized diamond powder, while the hydrophilic groups at the other end extend into the silane coupling agent solution, thereby significantly improving the dispersion stability and wettability of the ultrafine diamond powder in the aqueous system. After the grafting reaction, the powder is centrifuged, washed with ethanol, and dried at 100°C for 6 hours to obtain modified diamond powder with grafted hydrophilic groups.

[0070] Next, in step 130, the organic monomer (acrylamide AM) and the crosslinking agent (N,N'-methylenebisacrylamide MBAM) are dissolved in deionized water at a predetermined mass ratio of 12:1 and stirred until completely dissolved to obtain an organic monomer premix.

[0071] Then, the organic monomer premix obtained in step 130 can be placed in a beaker, and the shearing speed of the high-speed shear homogenizer can be adjusted to a predetermined shearing speed of 5000 rpm.

[0072] In step 140, microcrystalline glass binder powder and polymeric dispersant (0.5 wt.% ammonium polyacrylate dispersant) can be added to the organic monomer premix solution first, and then sheared and dispersed for 10 minutes using a high-speed shear homogenizer at a predetermined shear speed of 50,000 rpm. Modified diamond micropowder is then added, and further sheared and dispersed for 60 minutes using a high-speed shear homogenizer at a predetermined shear speed to obtain a ceramic slurry with high solid content (greater than 50%) and uniform dispersion. Specifically, based on a solid content of 55% for the ceramic slurry, 15% by mass of microcrystalline glass binder powder, 60% by mass of modified diamond micropowder, and 25% by mass of macroporous pore-forming agent (PS microspheres) can be pre-calculated and weighed, so that the corresponding masses of microcrystalline glass binder powder, modified diamond micropowder, and macroporous pore-forming agent (PS microspheres) can be added in steps 140 and 150, respectively.

[0073] Subsequently, in step 150, a macroporous pore-forming agent (PS microspheres) can be added to the ceramic slurry obtained in step 140 and stirred for 30 minutes to obtain a premixed ceramic slurry. Then, after fully defoaming the premixed ceramic slurry, an initiator (ammonium persulfate APS) and a catalyst (tetramethylethylenediamine TEMED) are added, and the mixture is quickly poured into a molding mold and placed in a 50°C water bath to initiate a polymerization reaction. This allows the organic monomers in the premixed ceramic slurry to undergo in-situ polymerization to form a three-dimensional polymer gel network. The three-dimensional polymer gel network can freeze and lock the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent in situ to form a wet blank with a certain strength.

[0074] In step 160, the demolded wet blank is first dried in a vacuum drying oven. Initially, it is dried at 45°C for 15 hours to allow the three-dimensional polymer gel network to shrink and form interconnected microporous channels. Then, the drying temperature is increased to 100°C, and the blank is dried at 100°C for 4 hours to achieve a constant weight. Afterward, the microporous dried blank is debonded and sintered as follows: the microporous dried blank is placed in a high-temperature sintering furnace, where the temperature is increased based on a segmented heating curve. Specifically, the temperature is first increased from 0°C to 400°C at a rate of 1°C / min, with holding at 300°C and 400°C for 180 minutes each. This low-temperature sintering process ensures the complete decomposition of various organic substances and pore-forming agents, allowing the microporous dried blank to expel organic matter and the polymer network. After holding at 400℃, the temperature is increased from 400℃ to a sintering temperature of 600℃ at a heating rate of 3℃ / min, and held at this sintering temperature for 2 hours. This allows the glass binder powder to melt and wet the modified diamond micropowder and precipitate reinforcing microcrystals. The mixture is then cooled to room temperature in the furnace to obtain a honeycomb structure grinding wheel block.

[0075] Finally, in step 170, the honeycomb structure grinding wheel block can be cut into corresponding honeycomb structure arc-shaped segments using a diamond wire cutter. Then, 30 honeycomb structure arc-shaped segments can be arrayed and adhered to the grooves of the aluminum alloy grinding wheel substrate at predetermined intervals, and cured using high-strength epoxy resin. After curing, the outer circle and end face are trimmed, and then the dynamic balance is adjusted to the G0.4 standard, thereby preparing a honeycomb porous wafer thinning grinding wheel.

[0076] In the second embodiment, the process of the method 100 for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting is as follows: In step 110, ultrafine diamond powder (W 0.5 μm diamond powder) is placed in a 30% hydrogen peroxide solution, and the pH value is adjusted to pH 4.5 using acetic acid solution as a pH adjuster. Then, it is heated at 60°C for 2 hours to remove impurities from the surface of the ultrafine diamond powder and introduce oxygen-containing active functional groups such as hydroxyl (-OH) and carboxyl (-COOH) groups onto the surface of the ultrafine diamond powder. Subsequently, the heat-treated ultrafine diamond powder is centrifuged and washed until neutral, and then dried at 100°C for 6 hours to obtain pre-oxidized diamond powder.

[0077] Subsequently, a 3% KH550 silane coupling agent solution after hydrolysis can be prepared in advance.

[0078] Next, in step 120, the pre-oxidized diamond powder obtained in step 110 is added to the prepared 3% KH550 silane coupling agent solution for a grafting reaction. The mixture is stirred at 60°C for 6 hours until the grafting reaction is complete. During the grafting reaction, the silanol groups at one end of the silane coupling agent undergo a condensation reaction with the hydroxyl groups on the surface of the pre-oxidized diamond powder, while the hydrophilic groups at the other end extend into the silane coupling agent solution, thereby significantly improving the dispersion stability and wettability of the ultrafine diamond powder in the aqueous system. After the grafting reaction, the powder is centrifuged, washed with ethanol, and dried at 100°C for 6 hours to obtain modified diamond powder with grafted hydrophilic groups.

[0079] Next, in step 130, the organic monomer (acrylamide AM) and the crosslinking agent (N,N'-methylenebisacrylamide MBAM) are dissolved in deionized water at a predetermined mass ratio of 24:1 and stirred until completely dissolved to obtain an organic monomer premix.

[0080] Then, the organic monomer premix obtained in step 130 can be placed in a beaker, and the shearing speed of the high-speed shear homogenizer can be adjusted to a predetermined shearing speed of 5000 rpm.

[0081] In step 140, microcrystalline glass binder powder and polymeric dispersant (0.5 wt.% ammonium polyacrylate dispersant) can be added to the organic monomer premix solution first, and then sheared and dispersed for 10 minutes using a high-speed shear homogenizer at a predetermined shear speed of 50,000 rpm. Modified diamond micropowder is then added, and further sheared and dispersed for 60 minutes using a high-speed shear homogenizer at a predetermined shear speed to obtain a ceramic slurry with high solid content (greater than 50%) and uniform dispersion. Specifically, 15% by mass of microcrystalline glass binder powder, 60% by mass of modified diamond micropowder, and 25% by mass of macroporous pore-forming agent (PS microspheres) can be pre-calculated and weighed based on a solid content of 50% for the ceramic slurry. These quantities can then be added in steps 140 and 150 according to the corresponding masses of microcrystalline glass binder powder, modified diamond micropowder, and macroporous pore-forming agent (PS microspheres).

[0082] Subsequently, in step 150, a macroporous pore-forming agent (PS microspheres) can be added to the ceramic slurry obtained in step 140 and stirred for 30 minutes to obtain a premixed ceramic slurry. Then, after fully defoaming the premixed ceramic slurry, an initiator (ammonium persulfate APS) and a catalyst (tetramethylethylenediamine TEMED) are added, and the mixture is quickly poured into a molding mold and placed in a 50°C water bath to initiate a polymerization reaction. This allows the organic monomers in the premixed ceramic slurry to undergo in-situ polymerization to form a three-dimensional polymer gel network. The three-dimensional polymer gel network can freeze and lock the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent in situ to form a wet blank with a certain strength.

[0083] In step 160, the demolded wet blank is first dried in a vacuum drying oven. Initially, it is dried at 45°C for 18 hours to allow the three-dimensional polymer gel network to shrink and form interconnected microporous channels. Then, the drying temperature is increased to 100°C, and the blank is dried at 100°C for 4 hours to achieve a constant weight. Afterward, the microporous dried blank is debonded and sintered as follows: the microporous dried blank is placed in a high-temperature sintering furnace, where the temperature is increased based on a segmented heating curve. Specifically, the temperature is first increased from 0°C to 400°C at a rate of 1°C / min, with holding at 300°C and 400°C for 180 minutes each. This low-temperature sintering process ensures the complete decomposition of various organic substances and pore-forming agents, allowing the microporous dried blank to expel organic matter and the polymer network. After holding at 400℃, the temperature is increased from 400℃ to a sintering temperature of 600℃ at a heating rate of 3℃ / min, and held at this sintering temperature for 2 hours. This allows the glass binder powder to melt and wet the modified diamond micropowder and precipitate reinforcing microcrystals. The mixture is then cooled to room temperature in the furnace to obtain a honeycomb structure grinding wheel block.

[0084] Finally, in step 170, the honeycomb structure grinding wheel block can be cut into corresponding honeycomb structure arc-shaped segments using a diamond wire cutter. Then, 30 honeycomb structure arc-shaped segments can be arrayed and adhered to the grooves of the aluminum alloy grinding wheel substrate at predetermined intervals, and cured using high-strength epoxy resin. After curing, the outer circle and end face are trimmed, and then the dynamic balance is adjusted to the G0.4 standard, thereby preparing a honeycomb porous wafer thinning grinding wheel.

[0085] It should be noted that the difference between the second embodiment and the first embodiment is that the predetermined mass ratio of organic monomer to crosslinking agent and the solid content of ceramic slurry are adjusted, thereby reducing the crosslinking density of the gel network and adjusting the microporous structure.

[0086] In the third embodiment, the process of the method 100 for preparing a honeycomb porous wafer thinning grinding wheel based on the in-situ gel casting method is as follows: In step 110, ultrafine diamond powder (W 0.5 μm diamond powder) is placed in a 30% hydrogen peroxide solution, and the pH value is adjusted to pH 4.5 using acetic acid solution as a pH adjuster. Then, it is heated at 60°C for 2 hours to remove impurities from the surface of the ultrafine diamond powder and introduce oxygen-containing active functional groups such as hydroxyl (-OH) and carboxyl (-COOH) groups onto the surface of the ultrafine diamond powder. Subsequently, the heat-treated ultrafine diamond powder is centrifuged and washed until neutral, and then dried at 100°C for 6 hours to obtain pre-oxidized diamond powder.

[0087] Subsequently, a 3% KH550 silane coupling agent solution after hydrolysis can be prepared in advance.

[0088] Next, in step 120, the pre-oxidized diamond powder obtained in step 110 is added to the prepared 3% KH550 silane coupling agent solution for a grafting reaction. The mixture is stirred at 60°C for 6 hours until the grafting reaction is complete. During the grafting reaction, the silanol groups at one end of the silane coupling agent undergo a condensation reaction with the hydroxyl groups on the surface of the pre-oxidized diamond powder, while the hydrophilic groups at the other end extend into the silane coupling agent solution, thereby significantly improving the dispersion stability and wettability of the ultrafine diamond powder in the aqueous system. After the grafting reaction, the powder is centrifuged, washed with ethanol, and dried at 100°C for 6 hours to obtain modified diamond powder with grafted hydrophilic groups.

[0089] Next, in step 130, the organic monomer (acrylamide AM) and the crosslinking agent (N,N'-methylenebisacrylamide MBAM) are dissolved in deionized water at a predetermined mass ratio of 6:1 and stirred until completely dissolved to obtain an organic monomer premix.

[0090] Then, the organic monomer premix obtained in step 130 can be placed in a beaker, and the shearing speed of the high-speed shear homogenizer can be adjusted to a predetermined shearing speed of 5000 rpm.

[0091] In step 140, microcrystalline glass binder powder and polymeric dispersant (0.5 wt.% ammonium polyacrylate dispersant) can be added to the organic monomer premix solution first, and then sheared and dispersed for 10 minutes using a high-speed shear homogenizer at a predetermined shear speed of 50,000 rpm. Modified diamond micropowder is then added, and further sheared and dispersed for 60 minutes using a high-speed shear homogenizer at a predetermined shear speed to obtain a ceramic slurry with high solid content (greater than 50%) and uniform dispersion. Specifically, 15% by mass of microcrystalline glass binder powder, 60% by mass of modified diamond micropowder, and 25% by mass of macroporous pore-forming agent (PS microspheres) can be pre-calculated and weighed based on a solid content of 50% for the ceramic slurry. These quantities can then be added in steps 140 and 150 according to the corresponding masses of microcrystalline glass binder powder, modified diamond micropowder, and macroporous pore-forming agent (PS microspheres).

[0092] Subsequently, in step 150, a macroporous pore-forming agent (PS microspheres) can be added to the ceramic slurry obtained in step 140 and stirred for 30 minutes to obtain a premixed ceramic slurry. Then, after fully defoaming the premixed ceramic slurry, an initiator (ammonium persulfate APS) and a catalyst (tetramethylethylenediamine TEMED) are added, and the mixture is quickly poured into a molding mold and placed in a 50°C water bath to initiate a polymerization reaction. This allows the organic monomers in the premixed ceramic slurry to undergo in-situ polymerization to form a three-dimensional polymer gel network. The three-dimensional polymer gel network can freeze and lock the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent in situ to form a wet blank with a certain strength.

[0093] In step 160, the demolded wet blank is first dried in a vacuum drying oven. Initially, it is dried at 45°C for 18 hours to allow the three-dimensional polymer gel network to shrink and form interconnected microporous channels. Then, the drying temperature is increased to 100°C, and the blank is dried at 100°C for 4 hours to achieve a constant weight. Afterward, the microporous dried blank is debonded and sintered as follows: the microporous dried blank is placed in a high-temperature sintering furnace, where the temperature is increased based on a segmented heating curve. Specifically, the temperature is first increased from 0°C to 400°C at a rate of 1°C / min, with holding at 300°C and 400°C for 180 minutes each. This low-temperature sintering process ensures the complete decomposition of various organic substances and pore-forming agents, allowing the microporous dried blank to expel organic matter and the polymer network. After holding at 400℃, the temperature is increased from 400℃ to a sintering temperature of 600℃ at a heating rate of 3℃ / min, and held at this sintering temperature for 2 hours. This allows the glass binder powder to melt and wet the modified diamond micropowder and precipitate reinforcing microcrystals. The mixture is then cooled to room temperature in the furnace to obtain a honeycomb structure grinding wheel block.

[0094] Finally, in step 170, the honeycomb structure grinding wheel block can be cut into corresponding honeycomb structure arc-shaped segments using a diamond wire cutter. Then, 30 honeycomb structure arc-shaped segments can be arrayed and adhered to the grooves of the aluminum alloy grinding wheel substrate at predetermined intervals, and cured using high-strength epoxy resin. After curing, the outer circle and end face are trimmed, and then the dynamic balance is adjusted to the G0.4 standard, thereby preparing a honeycomb porous wafer thinning grinding wheel.

[0095] It should be noted that the third embodiment aims to prepare a honeycomb porous wafer thinning wheel with ultra-high porosity. The difference between the third embodiment and the first embodiment is that the predetermined mass ratio of organic monomer to crosslinking agent and the solid content of ceramic slurry are adjusted, thereby increasing the crosslinking density of the gel network to support the honeycomb porous wafer thinning wheel with ultra-high porosity.

[0096] In addition, the present invention includes comparative embodiments as a control group for the first embodiment.

[0097] In the comparative embodiment, the grinding wheel can be prepared using the traditional dry pressing method based on the same formulation ratio. Specifically, the same W0.5μm ultrafine diamond powder and microcrystalline glass binder powder as in the first embodiment can be selected. It should be noted that since dry pressing does not involve water-based dispersion, the diamond powder is not hydrophilicated in the comparative embodiment; only a simple drying process is performed.

[0098] Furthermore, to obtain a porosity similar to that of the first embodiment, the same PS microspheres and their content were selected as macroporous pore-forming agents in the comparative embodiment. Also, based on the same mass percentages as in the first embodiment, 15% by mass of microcrystalline glass binder powder, 60% by mass of modified diamond micropowder, and 25% by mass of PS microspheres were pre-weighed. These powders were placed in a three-dimensional mixer, and an appropriate amount of 3% PVA solution was added as a temporary binder. The mixture was mixed for 4 hours, passed through a 200-mesh sieve, and a uniformly mixed granulated powder was obtained. The granulated powder was then filled into a steel mold and subjected to bidirectional cold pressing at 80 MPa for 60 seconds. Demolding yielded a green grinding wheel segment. The green grinding wheel segment was then placed in an oven and dried at 100°C for 12 hours, followed by debinding and sintering (the same debinding and sintering process as in the first embodiment) to obtain the grinding wheel segment. Finally, the grinding wheel segment array is glued into the grooves of the grinding wheel substrate to form a grinding wheel (comparison grinding wheel).

[0099] Furthermore, performance tests and grinding performance comparisons can be conducted on the honeycomb porous wafer thinning grinding wheels prepared in the first, second, third, and comparative embodiments described above. Specifically, the porosity of the grinding wheel can be tested using the Archimedes displacement method, and the bending strength of the grinding wheel can be tested using the three-point bending method. The honeycomb porous wafer thinning grinding wheels prepared in each embodiment are used to perform grinding tests on an eight-inch silicon carbide substrate on a wafer thinning machine. The grinding current and grinding wheel wear ratio are recorded, and the TTV (the difference between the maximum and minimum thickness, used to measure thickness uniformity) and surface roughness of the wafer after grinding are tested and recorded. Specific test data are shown in Table 1.

[0100] Table 1. Performance comparison of grinding wheels prepared in each embodiment in addition, Figure 4 The diagram shows the TTV and surface roughness results of the honeycomb porous wafers prepared by the in-situ gel casting method in the embodiment of the present invention and the dry pressing method in the comparative embodiment after grinding tests with thinning grinding wheels.

[0101] As shown in Table 1, by comparing the first and third embodiments with the comparative embodiments, it can be seen that the honeycomb porous wafer thinning grinding wheel prepared by the in-situ gel casting method according to the present invention has improved bending strength compared with the traditional dry pressing method while ensuring high porosity, and the grinding wheel wear is relatively low, resulting in a smaller surface roughness of the wafer after grinding.

[0102] As shown in Table 1 and Figure 4As shown, compared with the comparative embodiment, the honeycomb porous wafer thinning grinding wheel prepared by the in-situ gel casting method according to the embodiment of the present invention has a smaller TTV and surface roughness after grinding the wafer. In particular, the grinding wheel prepared according to the first embodiment has a surface roughness of less than 3nm after grinding the wafer.

[0103] In summary, the method for preparing honeycomb porous wafer thinning grinding wheels based on the in-situ gel casting method according to the present invention involves heating ultrafine diamond powder in an acidic, strongly oxidizing solution, followed by centrifugation, washing to neutrality, and drying to obtain pre-oxidized diamond powder. The pre-oxidized diamond powder is then added to a silane coupling agent solution for a grafting reaction, followed by centrifugation, ethanol washing, and drying to obtain modified diamond powder with surface-grafted hydrophilic groups. An organic monomer premix is ​​obtained by dissolving organic monomers and crosslinking agents in deionized water at a predetermined mass ratio and stirring until completely dissolved. Next, microcrystalline glass binder powder, polymeric dispersant, and modified diamond micropowder are sequentially added to the organic monomer premix, and dispersed to obtain a high-solids-content ceramic slurry. Then, a macroporous pore-forming agent is added to the ceramic slurry and stirred to obtain a premixed ceramic slurry. After thorough degassing of the premixed ceramic slurry, an initiator and catalyst are added and poured into a molding die. This allows the organic monomers to undergo in-situ polymerization at a predetermined polymerization temperature, forming a three-dimensional polymeric gel network. This allows the modified diamond micropowder, microcrystalline glass binder powder, and macroporous pore-forming agent to be frozen and locked in situ, forming a wet blank. The wet blank is then dried, debinded, and sintered to allow the microcrystalline glass binder powder to melt and wet the modified diamond micropowder, precipitating a microcrystalline phase, resulting in a honeycomb structure grinding wheel block. Finally, the honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments and arrayed and pasted into the grooves of the grinding wheel substrate to form a honeycomb porous wafer thinning grinding wheel.

[0104] Based on this, the present invention overcomes the agglomeration problem caused by the high surface energy of ultrafine diamond powder in the traditional dry pressing process by combining surface hydrophilic modification with liquid phase in-situ curing technology. On the other hand, the rapid in-situ curing of the gel network can freeze the dispersed state instantly, ensuring that the modified diamond powder and pores are evenly distributed in the grinding wheel structure, thereby avoiding scratches caused by local enrichment of the grinding wheel during the wafer thinning process.

[0105] Secondly, the honeycomb structure grinding wheel block prepared according to the present invention has spherical macropores left by the burn-off of the macropore-forming agent. These macropores are large and regular in size, providing ample chip space for the grinding wheel to thin the wafer. Simultaneously, it has micropores formed by the shrinkage of the gel network during drying. These micropores can connect with the isolated macropores to form a three-dimensional, interconnected coolant delivery channel. This dual-pore honeycomb structure ensures excellent heat dissipation and chip removal capabilities while avoiding structural breakage caused by traditional macropore-forming agents. It can significantly reduce the grinding temperature during the grinding wheel's thinning process, preventing wafer burn-out.

[0106] Furthermore, the wet blank formed by the gel casting process has a uniform microstructure, and the microcrystalline glass binder improves the intrinsic strength of the glass through the microcrystalline toughening mechanism during sintering. This allows the final grinding wheel to maintain a high porosity (up to 50-70%) while improving its bending strength (more than 20% higher than traditional processes), thus meeting the safety requirements of high-speed ultra-precision grinding.

[0107] Furthermore, the honeycomb porous wafer thinning grinding wheel finally prepared according to the present invention has a uniform structure, good self-sharpening properties and stable grinding force. When using this grinding wheel to grind and thin large-size silicon carbide wafers, it can effectively suppress grinding vibration and central pit defects, and achieve efficient and low-damage mirror thinning.

[0108] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0109] Similarly, it should be understood that, in order to streamline this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof.

[0110] Those skilled in the art will understand that the modules, units, or components of the devices in the examples disclosed herein may be arranged in the devices described in this embodiment, or alternatively may be located in one or more devices different from the devices in this example.

[0111] Those skilled in the art will understand that the modules in the device of the embodiment can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiment can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components.

[0112] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention and form different embodiments.

[0113] As used herein, unless otherwise specified, the use of ordinal numbers such as “first,” “second,” “third,” etc., to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, ordering, or any other manner.

[0114] Although the invention has been described with respect to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and edibility purposes, and not for the purpose of explaining or limiting the subject matter of the invention.

Claims

1. A method for preparing a honeycomb porous wafer thinning grinding wheel based on in-situ gel casting, comprising: Ultrafine diamond powder is placed in an acidic, strongly oxidizing solution and heated to remove impurities from the surface of the ultrafine diamond powder and introduce oxygen-containing active functional groups on the surface of the ultrafine diamond powder. The heated ultrafine diamond powder is then centrifuged, washed until neutral, and dried to obtain pre-oxidized diamond powder. The pre-oxidized diamond micro powder was added to a silane coupling agent solution for grafting reaction, and after the reaction was completed, it was centrifuged, washed with ethanol, and dried to obtain modified diamond micro powder with surface-grafted hydrophilic groups. The organic monomer and crosslinking agent are dissolved in deionized water at a predetermined mass ratio and stirred until completely dissolved to obtain an organic monomer premix. Microcrystalline glass binder powder and polymeric dispersant, as well as the modified diamond micro powder, are sequentially added to the organic monomer premix liquid and dispersed to obtain a ceramic slurry with a solid content greater than the solid content threshold. A macroporous pore-forming agent is added to the ceramic slurry and stirred to obtain a premixed ceramic slurry. After the premixed ceramic slurry is fully defoamed, an initiator and a catalyst are added, and the slurry is poured into a molding mold so that the organic monomers in the premixed ceramic slurry undergo in-situ polymerization at a predetermined polymerization temperature to form a three-dimensional polymer gel network. The modified diamond micro powder, microcrystalline glass binder powder, and macroporous pore-forming agent are frozen and locked in situ to form a wet blank. The wet blank is dried, debinded, and sintered so that the microcrystalline glass binder powder melts and wets the modified diamond micro powder and precipitates the microcrystalline phase, thus obtaining a honeycomb structure grinding wheel block; The honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments, and multiple honeycomb structure arc-shaped segments are attached to the grooves of the grinding wheel substrate to form a honeycomb porous wafer thinning grinding wheel.

2. The method as described in claim 1, wherein, Microcrystalline glass binder powder and polymeric dispersant, along with the modified diamond micro powder, are sequentially added to the organic monomer premix, and then dispersed to obtain a ceramic slurry with a solid content greater than a solid content threshold, comprising: Microcrystalline glass binder powder and polymeric dispersant, as well as the modified diamond micro powder, are added sequentially to the organic monomer premix to obtain an initial slurry; The initial slurry is adjusted to alkalinity and then ball-milled or ultrasonically dispersed to obtain a ceramic slurry with a solid content greater than the solid content threshold.

3. The method as described in claim 1, wherein, Microcrystalline glass binder powder and polymeric dispersant, along with the modified diamond micro powder, are sequentially added to the organic monomer premix, and then dispersed to obtain a ceramic slurry with a solid content greater than a solid content threshold, comprising: Microcrystalline glass binder powder and polymeric dispersant are first added to the organic monomer premix liquid. After shearing and dispersing for 10 minutes using a high-speed shear homogenizer at a predetermined shear speed, modified diamond micro powder is added. Then, the mixture is sheared and dispersed for 40-60 minutes using the same high-speed shear homogenizer at the predetermined shear speed to obtain a ceramic slurry with a solid content greater than the solid content threshold.

4. The method according to any one of claims 1-3, wherein, The total mass percentage of the microcrystalline glass binder powder, modified diamond micro powder, and macroporous pore-forming agent added to the organic monomer premix liquid is 1, wherein the mass percentage of the microcrystalline glass binder powder is 15-20%, the mass percentage of the modified diamond micro powder is 55-65%, and the mass percentage of the macroporous pore-forming agent is 20-30%.

5. The method according to any one of claims 1-4, wherein, The wet blank is dried, debinded, and sintered to melt and wet the modified diamond micropowder with the glass-ceramic binder powder and precipitate the microcrystalline phase, resulting in a honeycomb structure grinding wheel block, comprising: The wet blank is dried in a vacuum drying oven so that the three-dimensional polymer gel network loses water and shrinks to form interconnected microporous channels, and a microporous structure dried blank is obtained. Based on a segmented heating curve that includes low-temperature and high-temperature stages, the microporous structure dry blank is sintered so that the microporous structure dry blank discharges organic matter and polymer network in the low-temperature stage, and the microcrystalline glass binder powder melts and wets the modified diamond micro powder and precipitates microcrystalline phase in the high-temperature stage to obtain a honeycomb structure grinding wheel block.

6. The method of claim 5, wherein, The low-temperature stage includes: heating from 0°C to 400°C at a heating rate of 1-2°C / min, wherein the temperature is held at 300°C and 400°C for 120-180min respectively. The high-temperature stage includes: heating from 400℃ to the sintering temperature at a heating rate of 3-5℃ / min, and holding at the sintering temperature for 2-3 hours, wherein the sintering temperature is 550-650℃.

7. The method according to any one of claims 1-6, wherein, The pre-oxidized diamond micropowder is added to a silane coupling agent solution for a grafting reaction, including: The pre-oxidized diamond micro powder was added to a silane coupling agent solution for a grafting reaction, wherein the mixture was stirred at 40-80°C for 4-6 hours until the grafting reaction was completed.

8. The method according to any one of claims 1-7, wherein, The honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments, and multiple honeycomb structure arc-shaped segments are arrayed and pasted into the grooves of the grinding wheel substrate to form a honeycomb porous wafer thinning grinding wheel, including: The honeycomb structure grinding wheel block is cut into corresponding honeycomb structure arc-shaped segments using a diamond wire cutting machine; According to a predetermined spacing, multiple honeycomb structure arc-shaped segment arrays are pasted into the grooves of the grinding wheel substrate, and after curing, they are trimmed and dynamically balanced to obtain a honeycomb porous wafer thinning grinding wheel.

9. The method according to any one of claims 1-8, wherein, The organic monomer is acrylamide or methacrylamide, and the crosslinking agent is N,N'-methylenebisacrylamide; The predetermined mass ratio is 6:1 to 30:

1.

10. The method according to any one of claims 1-8, wherein, The strong acidic oxidizing agent solution is a potassium permanganate solution or a hydrogen peroxide solution; The oxygen-containing active functional groups include hydroxyl and carboxyl groups; The silane coupling agent solution is a pre-prepared hydrolyzed 1-5% silane coupling agent solution, and the silane coupling agent solution is any one of KH550, KH560, and KH570; The polymeric dispersant is ammonium polyacrylate dispersant or polyvinylpyrrolidone dispersant; The initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine.

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