Preparation method and device of precision machining tool for thinning silicon carbide wafer

Abstract

The invention discloses a method and device for preparing a precision machining tool for thinning a silicon carbide wafer, and the method comprises the following steps: determining the particle sizes and proportions of a diamond abrasive, a pore forming agent and a ceramic bond, the proportion of an additive and a target porosity, verifying the target porosity through an analogue simulation experiment, the proportion of the raw materials is adjusted; a ceramic bond sample is prepared, the thermal expansion coefficient of the ceramic bond sample is obtained, and meanwhile, the components of the ceramic bond are optimized according to the thermal expansion coefficient of the diamond abrasive. The relation between the percentage of each raw material and the target porosity is established through an analogue simulation experiment, the raw materials can be precisely regulated and controlled under the condition that the porosity is guaranteed, meanwhile, the performance of the superhard grinding wheel can be remarkably improved by comparing the thermal expansion coefficients of the ceramic bond and the diamond and regulating and controlling the thermal expansion coefficient of the ceramic bond, and the performance of the superhard grinding wheel is improved. And an efficient and reliable preparation method is provided for thinning the silicon carbide wafer.

Description

Technical Field

[0001] The invention relates to the technical field of superhard grinding wheel preparation for silicon carbide wafer thinning, and in particular to a method and device for preparing a precision machining tool for silicon carbide wafer thinning. Background Art

[0002] In the silicon carbide wafer thinning process, super-hard grinding wheels play a key role. Their performance directly affects the quality and efficiency of wafer thinning. Currently, the preparation of super-hard grinding wheels faces many challenges.

[0003] In the existing preparation methods, it is relatively complicated to determine the appropriate proportion of each raw material. When determining the raw material proportion using the traditional method, the porosity of the tool is often not taken into consideration. Instead, the proportion of each raw material is directly and slowly increased or decreased. This usually requires a lot of time and cost for repeated trial and error, and it is difficult to quickly obtain reliable raw material proportion data; in addition, the mismatch problem of thermal expansion coefficients of diamond abrasives and ceramic binders is also more prominent. In the preparation of grinding wheels, the thermal expansion coefficients of diamond and ceramic binders are very different, which will lead to inconsistent contraction of the two during the cooling stage after firing. In the process of using the grinding wheel, the thermal expansion coefficients of diamond and ceramic binders are very different, and ultra-high-speed grinding will also cause asynchronous expansion due to heat. These two factors will eventually lead to a gap between diamond and ceramic binder, seriously affecting the performance of the grinding wheel and reducing its service life and grinding accuracy. Therefore, an innovative method for preparing superhard grinding wheels is proposed to solve the above problems.

[0004] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0005] In view of the problems in the related art, the present invention proposes a method and device for preparing a precision machining tool for thinning a silicon carbide wafer, so as to overcome the above-mentioned technical problems existing in the existing related art.

[0006] To this end, the specific technical solution adopted by the present invention is as follows:

[0007] A method for preparing a precision machining tool for thinning a silicon carbide wafer, the method comprising the following steps:

[0008] S1. Determine the particle size and ratio of diamond abrasive, pore former, ceramic binder, the ratio of additives and target porosity, verify the target porosity through simulation experiments, and adjust the ratio of each raw material;

[0009] S2. preparing a ceramic binder sample and obtaining its thermal expansion coefficient, and optimizing the composition of the ceramic binder according to the thermal expansion coefficient of the diamond abrasive;

[0010] S3, preparing a ceramic binder and a pore-forming agent, and preparing each raw material into a mixed dry powder and adding paraffin wax, rolling and mixing the mixed dry powder to obtain a mixed wet material, and finally sieving and drying the mixed wet material to obtain a shaped abrasive;

[0011] S4, pouring the formed abrasive into the mold, hot pressing it into a cutter head and sintering it, and using a binder to bond the cutter head to the groove of the base, and finally grinding the grinding wheel cutter head.

[0012] As a preferred embodiment, the determination of the particle size and ratio of diamond abrasive, pore former, and vitrified binder, the ratio of additives, and target porosity, verifying the target porosity through simulation experiments, and adjusting the ratio of each raw material includes the following steps:

[0013] S11, determine the particle size and ratio of diamond abrasive, pore former, ceramic binder, the ratio of additives and the target porosity, and construct the geometric shape of each raw material in ANSYS simulation software, and at the same time construct the initial microstructure geometric model of the abrasive tool based on the ratio of each raw material;

[0014] S12, assigning corresponding properties to each raw material, and simulating its internal mechanical behavior and pore structure formation process, and finally meshing the constructed geometric model to generate a finite element mesh. At the same time, according to the actual preparation method, the corresponding pressure load is applied in the simulation model to observe the movement of particles and the change of pore structure;

[0015] S13. After the simulation experiment is completed, the microstructure image of the mold is obtained, and the image is analyzed using image processing technology to distinguish between pores and solid phases. Finally, the porosity of the simulation model is obtained by calculating the ratio of the area or volume of the pore region to the total volume. The calculated simulation porosity is compared with the target porosity. When the porosity is within the error range of ±1%, it means that the current proportion of each raw material meets the requirements. When the error range exceeds ±1%, the component proportion of each raw material is adjusted.

[0016] As a preferred embodiment, the calculated simulated porosity is compared with the target porosity. When the porosity is within the error range of ±1%, it means that the current proportions of the raw materials meet the requirements. When the error range exceeds ±1%, adjusting the proportions of the raw materials includes the following steps:

[0017] S131. Calculate the porosity. The specific formula is:

[0018]

[0019] Where p is the calculated porosity, D1 and D2 are the volume of the pore area and the total volume, respectively;

[0020] When the error range exceeds ±1%, adjust the simulation experiment parameters to obtain data to establish the porosity and diamond abrasive, pore-forming agent, and ceramic binder. percentage The mathematical model is:

[0021] P1=P0+α·B1-β·B2-γ·B3;

[0022] Among them, P1 is the actual porosity, P0 is the porosity without diamond and pore-forming agent, α is the enhancement coefficient of pore-forming agent on porosity, β is the inhibition coefficient of diamond on porosity, γ is the inhibition coefficient of binder on porosity, B1, B2, B3 are Pore ​​forming agent percentage, diamond abrasive percentage, vitrified bond percentage ;

[0023] Calculate the porosity difference that needs to be increased or decreased and establish the equation system:

[0024] ΔP=α·ΔB1-β·ΔB2-γ·ΔB3;

[0025] 0 = ΔB1 + ΔB2 + ΔB3;

[0026] Solve the equation group, and set the adjustment weight w1 of the pore former to be the highest, the weight w2 of the ceramic binder to be the second, and the weight w3 of the pore former to be the third, to obtain the adjustment ratio of each raw material;

[0027] A secondary simulation experiment is conducted on the ratio of each raw material to verify the porosity. When the porosity is within the normal range, the raw material ratio is output. When the porosity exceeds the normal range, the ratio of each raw material is further adjusted.

[0028] Research on raw materials percentage The relationship between porosity and porosity can not only simplify the steps of optimizing the raw material ratio, but also reasonably optimize the porosity, thereby greatly improving the overall hardness and wear resistance of the material.

[0029] As a preferred embodiment, the steps of preparing a ceramic binder sample and obtaining its thermal expansion coefficient, and optimizing the composition of the ceramic binder according to the thermal expansion coefficient of the diamond abrasive are as follows:

[0030] S21. Prepare a small amount of ceramic binder sample, weigh by mass percentage, silicon dioxide: 45% to 55%, boron oxide: 15% to 25%, aluminum oxide: Al2O3, potassium oxide: 3% to 7%, sodium oxide: 2% to 5%, titanium oxide: 2% to 4%, phosphorus pentoxide: 1% to 2%, ball mill to mix evenly, sieve to obtain a mixed powder, drip the mixed powder into deionized water after melting, dry, ball mill for 1 hour to obtain ceramic binder powder, sieve through a 600# sieve to obtain a sample;

[0031] S22, preset a difference range of thermal expansion coefficients of diamond abrasive and ceramic binder, and obtain the thermal expansion coefficient of ceramic binder, compare the thermal expansion coefficients of ceramic binder and diamond abrasive, and directly proceed to the next step of mixing when they do not exceed the preset range, and when they exceed the preset range, prepare a mixture and add it to the ceramic binder so that the thermal expansion coefficient of the ceramic binder is within the preset range.

[0032] As a preferred embodiment, when the thermal expansion coefficient of the ceramic binder exceeds the preset range, preparing the mixture and adding the ceramic binder so that the thermal expansion coefficient of the ceramic binder is within the preset range comprises the following steps:

[0033] S221. When the thermal expansion coefficient of the ceramic binder exceeds a preset range, a mixture of eucryptite and zirconium oxide composite powders is prepared, wherein the ratio of eucryptite to zirconium oxide is 7:3, a small amount of the mixture is added to the sample, and the thermal expansion coefficient of the sample is verified;

[0034] S222. Calculate the amount of composite powder added based on the difference in thermal expansion coefficients, and modify the raw materials of the ceramic binder. The specific raw materials are silicon dioxide: 45% to 55%, boron oxide: 15% to 25%, aluminum oxide: Al2O3, potassium oxide: 3% to 7%, sodium oxide: 2% to 5%, titanium oxide: 2% to 4%, phosphorus pentoxide: 1% to 2%, and mixture: 3% to 5%.

[0035] As a preferred embodiment, the preparation of the ceramic binder and the pore-forming agent, preparing the raw materials into a mixed dry powder and adding paraffin wax, rolling and mixing the mixed dry powder to obtain a mixed wet material, and finally sieving and drying the mixed wet material to obtain a shaped abrasive comprises the following steps:

[0036] S31, prepare a pore-forming agent, weigh hollow glass balls, sodium bicarbonate and dizodicarbonyl in a ratio of 3:1:2, dissolve sodium bicarbonate and dizodicarbonyl in ethanol, mix them evenly by ultrasonication for 30 minutes, put them in an oven for drying, then add the hollow glass balls, ball mill them for 3 hours, and sieve through a 200# sieve to obtain a composite pore-forming agent;

[0037] S32, preparing a ceramic binder, ball-milling raw materials of the ceramic binder to mix evenly, sieving to obtain a mixed powder, melting the mixed powder and dropping it into deionized water, drying, ball-milling for 1 hour to obtain a ceramic binder powder, and sieving through a 600# sieve to obtain a ceramic binder;

[0038] S33, diamond abrasive, ceramic binder and pore-forming agent are mixed in a three-dimensional mixer for 1-2 hours, and then hexagonal boron nitride additive is added, and mixing is continued for 1-2 hours to obtain a mixed dry powder.

[0039] S34. Put the mixed dry powder into a mortar and add paraffin. The ratio of the mixed dry powder to the paraffin is (5-6):1. Use the mortar to mix the dry powder and the paraffin by rolling to obtain a mixed wet material. After sieving the mixed wet material with 60#, put it into an oven and dry it for 10-15 hours to obtain a shaped abrasive.

[0040] As a preferred embodiment, the step of pouring the shaped abrasive into the grinding tool, hot pressing to form a cutter head, sintering the cutter head, and bonding the cutter head to the groove of the base body with a binder, and finally grinding the grinding wheel cutter head comprises the following steps:

[0041] S41, set the pressure to 2-8Mpa, pour the formed abrasive into the mold and hot press at 120℃ for 10-15min, finally put the pressed formed cutter head into a sintering furnace for sintering at a sintering temperature of 550℃-850℃;

[0042] S42, bonding the cutter heads to the grooves of the substrate using an epoxy resin adhesive, and ensuring that the cutter heads are spaced evenly apart and the sides are perpendicular to the surface of the substrate;

[0043] S43. Use a surface grinder to grind the end face of the grinding wheel cutter.

[0044] A device for preparing a precision machining tool for thinning a silicon carbide wafer, the device is used in the preparation of a precision machining tool for thinning a silicon carbide wafer, comprising a memory and a processor:

[0045] a memory for non-transitory storage of computer readable instructions;

[0046] A processor is used to execute the computer-readable instructions; wherein, when the computer-readable instructions are executed by the processor, any of the above methods is executed.

[0047] The beneficial effects of the present invention are:

[0048] 1. The present invention conducts simulation experiments on the determined raw material ratios through simulation experiments to obtain the porosity of the tool made under the original raw material ratio. When the simulated porosity exceeds the normal error range, the porosity of each raw material is established. percentage The porosity model can quickly obtain the adjustment amount of each raw material, and the porosity of the tool can be guaranteed while adjusting each raw material. Therefore, this step can quickly obtain raw material proportion data, ensure tool quality, and reduce trial and error costs.

[0049] 2. In order to solve the problem of thermal expansion coefficient mismatch between diamond abrasive and ceramic binder, the present invention adds a mixture made of eucryptite and zirconium oxide, which can effectively reduce the thermal expansion coefficient of the ceramic binder and ensure that the thermal expansion coefficients of the binder and diamond are matched as much as possible. This not only makes the contraction of diamond and binder similar during the cooling stage after firing, but also makes the thermal expansion similar during ultra-high-speed grinding, avoiding the generation of gaps between diamond and ceramic binder, thereby affecting performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 The present invention is a flow chart of a method for preparing a precision machining tool for thinning a silicon carbide wafer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0053] According to an embodiment of the present invention, a method and apparatus for preparing a precision machining tool for thinning a silicon carbide wafer are provided.

[0054] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, a method and device for preparing a precision machining tool for thinning a silicon carbide wafer according to an embodiment of the present invention comprises the following steps:

[0055] Embodiment 1

[0056] S1. Determine the particle size and ratio of diamond abrasive, pore former, ceramic binder, the ratio of additives and target porosity, verify the target porosity through simulation experiments, and adjust the ratio of each raw material;

[0057] Furthermore, the determination of the particle size and ratio of diamond abrasive, pore former, and vitrified binder, the ratio of additives, and target porosity, verifying the target porosity through simulation experiments, and adjusting the ratio of each raw material includes the following steps:

[0058] S11, determine the particle size and ratio of diamond abrasive, pore former, ceramic binder, the ratio of additives and the target porosity, and construct the geometric shape of each raw material in ANSYS simulation software, and at the same time construct the initial microstructure geometric model of the abrasive tool based on the ratio of each raw material;

[0059] S12, assigning corresponding properties to each raw material, and simulating its internal mechanical behavior and pore structure formation process, and finally meshing the constructed geometric model to generate a finite element mesh. At the same time, according to the actual preparation method, the corresponding pressure load is applied in the simulation model to observe the movement of particles and the change of pore structure;

[0060] S13. After the simulation experiment is completed, the microstructure image of the abrasive tool is obtained, and the image is analyzed using image processing technology to distinguish the pores and solid phases. Finally, the porosity of the simulation model is obtained by calculating the ratio of the area or volume of the pore region to the total volume. The calculated simulation porosity is compared with the target porosity. When the porosity is within the error range of ±1%, it means that the current proportion of each raw material meets the requirements. When the error range exceeds ±1%, the composition ratio of each raw material is adjusted.

[0061] Furthermore, the calculated simulated porosity is compared with the target porosity. When the porosity is within the error range of ±1%, it indicates that the current proportions of the raw materials meet the requirements. When the error range exceeds ±1%, adjusting the proportions of the raw materials includes the following steps:

[0062] S131. Calculate the porosity. The specific formula is:

[0063]

[0064] Where p is the calculated porosity, D1 and D2 are the volume of the pore area and the total volume, respectively;

[0065] When the error range exceeds ±1%, adjust the simulation experiment parameters to obtain data to establish the porosity and diamond abrasive, pore-forming agent, and ceramic binder. percentage The mathematical model is:

[0066] P1=P0+α·B1-β·B2-γ·B3;

[0067] Among them, P1 is the actual porosity, P0 is the porosity without diamond and pore-forming agent, α is the enhancement coefficient of pore-forming agent on porosity, β is the inhibition coefficient of diamond on porosity, γ is the inhibition coefficient of binder on porosity, B1, B2, B3 are Pore ​​forming agent percentage, diamond abrasive percentage, vitrified bond percentage ;

[0068] Calculate the porosity difference that needs to be increased or decreased and establish the equation system:

[0069] ΔP=α·ΔB1-β·ΔB2-γ·ΔB3;

[0070] 0 = ΔB1 + ΔB2 + ΔB3;

[0071] Solve the equation group, and set the adjustment weight w1 of the pore former to be the highest, the weight w2 of the ceramic binder to be the second, and the weight w3 of the pore former to be the third, to obtain the adjustment ratio of each raw material;

[0072] A secondary simulation experiment is conducted on the ratio of each raw material to verify the porosity. When the porosity is within the normal range, the raw material ratio is output. When the porosity exceeds the normal range, the ratio of each raw material is further adjusted.

[0073] It should be noted that by optimizing the raw material formula ratio through simulation experiments, it is possible to systematically analyze each component percentage The relationship between porosity and material can be precisely controlled while avoiding a large number of repeated trial and error experiments, thereby improving product strength, permeability and other functional properties, shortening the R&D cycle and reducing raw material waste, and achieving multi-objective balanced optimization of performance, cost and process feasibility.

[0074] S2. preparing a ceramic binder sample and obtaining its thermal expansion coefficient, and optimizing the composition of the ceramic binder according to the thermal expansion coefficient of the diamond abrasive;

[0075] Furthermore, the specific steps of preparing a ceramic binder sample and obtaining its thermal expansion coefficient, and optimizing the composition of the ceramic binder according to the thermal expansion coefficient of the diamond abrasive are as follows:

[0076] S21. Prepare a small amount of ceramic binder sample, weigh by mass percentage, silicon dioxide: 45%-55%, boron oxide: 15%-25%, aluminum oxide: 15%-20%, potassium oxide: 3%-7%, sodium oxide: 2%-5%, titanium oxide: 2%-4%, phosphorus pentoxide: 1%-2%, ball mill to mix evenly, sieve to obtain a mixed powder, drip the mixed powder into deionized water after melting, dry, ball mill for 1 hour to obtain ceramic binder powder, sieve through a 600# sieve to obtain a sample;

[0077] S22, preset a difference range of thermal expansion coefficients of diamond abrasive and ceramic binder, and obtain the thermal expansion coefficient of ceramic binder, compare the thermal expansion coefficients of ceramic binder and diamond abrasive, and directly proceed to the next step of mixing when they do not exceed the preset range, and when they exceed the preset range, prepare a mixture and add it to the ceramic binder so that the thermal expansion coefficient of the ceramic binder is within the preset range.

[0078] It should be noted that the coefficient of thermal expansion of the ceramic binder must be as close to or lower than that of diamond as possible. If the CTE of the binder is higher than that of diamond, the binder will expand more when the temperature rises, which will produce tensile stress at the interface between the diamond particles and the binder, leading to microcracks or even particle shedding. If the CTE of the binder is lower than that of diamond, the binder will shrink slightly more when cooling, which will instead form a slight compressive stress on the diamond and enhance the interface bonding strength.

[0079] Furthermore, when the temperature exceeds the preset range, preparing the mixture and adding the ceramic binder so that the thermal expansion coefficient of the ceramic binder is within the preset range comprises the following steps:

[0080] S221. When the thermal expansion coefficient of the ceramic binder exceeds a preset range, a mixture of eucryptite and zirconium oxide composite powders is prepared, wherein the ratio of eucryptite to zirconium oxide is 7:3, a small amount of the mixture is added to the sample, and the thermal expansion coefficient of the sample is verified;

[0081] S222. Calculate the amount of composite powder added based on the difference in thermal expansion coefficients, and modify the raw materials of the ceramic binder. The specific raw materials are silicon dioxide: 45% to 55%, boron oxide: 15% to 25%, aluminum oxide: 15% to 20%, potassium oxide: 3% to 7%, sodium oxide: 2% to 5%, titanium oxide: 2% to 4%, phosphorus pentoxide: 1% to 2%, and mixture: 3% to 5%.

[0082] S3, preparing a ceramic binder and a pore-forming agent, and preparing each raw material into a mixed dry powder and adding paraffin wax, rolling and mixing the mixed dry powder to obtain a mixed wet material, and finally sieving and drying the mixed wet material to obtain a shaped abrasive;

[0083] Furthermore, the preparation of the ceramic binder and the pore-forming agent, preparing the raw materials into a mixed dry powder and adding paraffin wax, rolling and mixing the mixed dry powder to obtain a mixed wet material, and finally sieving and drying the mixed wet material to obtain a shaped abrasive comprises the following steps:

[0084] S31, prepare a pore-forming agent, weigh hollow glass balls, sodium bicarbonate and dizodicarbonyl in a ratio of 3:1:2, dissolve sodium bicarbonate and dizodicarbonyl in ethanol, mix them evenly by ultrasonication for 30 minutes, put them in an oven for drying, then add the hollow glass balls, ball mill them for 3 hours, and sieve through a 200# sieve to obtain a composite pore-forming agent;

[0085] S32, preparing a ceramic binder, ball-milling raw materials of the ceramic binder to mix evenly, sieving to obtain a mixed powder, melting the mixed powder and dropping it into deionized water, drying, ball-milling for 1 hour to obtain a ceramic binder powder, and sieving through a 600# sieve to obtain a ceramic binder;

[0086] S33, diamond abrasive, ceramic binder and pore-forming agent are mixed in a three-dimensional mixer for 1-2 hours, and then hexagonal boron nitride additive is added, and mixing is continued for 1-2 hours to obtain a mixed dry powder.

[0087] S34. Put the mixed dry powder into a mortar and add paraffin. The ratio of the mixed dry powder to the paraffin is (5-6):1. Use the mortar to mix the dry powder and the paraffin by rolling to obtain a mixed wet material. After sieving the mixed wet material with 60#, put it into an oven and dry it for 10-15 hours to obtain a shaped abrasive.

[0088] S4. Pour the formed abrasive into the mold, hot press it into a cutter head, sinter it, and use a binder to bond the cutter head to the groove of the base body. Finally, grind the grinding wheel cutter head.

[0089] Furthermore, the step of pouring the shaped abrasive into the grinding tool, hot pressing it into a cutter head, sintering it, and bonding the cutter head to the groove of the base body with a binder, and finally grinding the grinding wheel cutter head comprises the following steps:

[0090] S41, set the pressure to 2-8Mpa, pour the formed abrasive into the mold and hot press at 120℃ for 10-15min, finally put the pressed formed cutter head into a sintering furnace for sintering at a sintering temperature of 550℃-850℃;

[0091] S42, bonding the cutter heads to the grooves of the substrate using an epoxy resin adhesive, and ensuring that the cutter heads are spaced evenly apart and the sides are perpendicular to the surface of the substrate;

[0092] S43. Use a surface grinder to grind the end face of the grinding wheel cutter.

[0093] A device for preparing a precision machining tool for thinning a silicon carbide wafer, the device is used in the preparation of a precision machining tool for thinning a silicon carbide wafer, comprising a memory and a processor:

[0094] a memory for non-transitory storage of computer readable instructions;

[0095] A processor is used to execute the computer-readable instructions; wherein, when the computer-readable instructions are executed by the processor, any of the above methods is executed.

[0096] Embodiment 2

[0097] This example applies the preparation of the mixture and the amount of the mixture added. The specific process and preparation process are as follows:

[0098] Weigh eucryptite and chlorine oxide according to the proportion and measure the thermal expansion coefficient:

[0099] 7:3 ratio: CTE≈6.5–7.5×10 -6 / ℃;

[0100] 5:5 ratio: CTE≈8.0×10 -6 / ℃;

[0101] 1:9 ratio: CTE≈9.2×10 -6 / ℃;

[0102] According to the thermal expansion coefficient, the ratio of eucryptite to chlorine oxide is 7:3, which is the most suitable ratio for ceramic binder.

[0103] The relationship between the CTE of the mixture addition and the mechanical properties was verified by gradient experiments. The data examples are shown in Table 1 below.

[0104] Table 1: Relationship between CTE and mechanical properties of mixture addition

[0105]

[0106] It can be seen from the table that when the mixture addition amount is 3%-5%, the CTE decreases from 8.5 to (6.9×10 -6 / ℃, enter the preset range (6.5–7.5×10 -6 / ℃), and the strength remains ≥270MPa. When the mixture addition amount is >5%, the CTE is further reduced, but the strength and density are significantly reduced. Therefore, it can be concluded that the mixture addition amount is 3%-5% as the optimal addition amount.

[0107] Embodiment 3

[0108] This example uses 2000# diamond powder to prepare wafer thinning superhard grinding wheels. The specific process and preparation process are as follows:

[0109] Firstly, the mass percentages of specific raw materials are obtained through simulation experiments, namely, 50% silicon dioxide, 20% boron oxide, 15% aluminum oxide, 6% potassium oxide, 3% sodium oxide, 2% titanium oxide, 1% phosphorus pentoxide, and 3% mixture. The mixture is evenly mixed by ball milling and sieved to obtain a mixed powder. After the mixed powder is melted, it is dripped into deionized water, dried, and ball milled for 1 hour to obtain ceramic binder powder. The ceramic binder is sieved through a 600# sieve.

[0110] Preparation of composite pore-forming agent: hollow glass balls, sodium bicarbonate and dizodicarbonyl were weighed in a ratio of 3:1:2, sodium bicarbonate and dizodicarbonyl were dissolved in ethanol, ultrasonically mixed for 30 minutes, dried in an oven, and then hollow glass balls were added, ball milled for 3 hours, and the composite pore-forming agent was sieved through a 200# sieve.

[0111] Weigh the diamond abrasive 40%, the ceramic binder 25%, the pore-forming agent 31%, and the additive 4% by mass. Mix the diamond abrasive, the ceramic binder, and the pore-forming agent, put them into a three-dimensional mixer and mix them for 1 hour, then add the additive hexagonal boron nitride, and continue mixing for 1 hour to obtain a mixed dry powder.

[0112] Put the mixed dry powder into a mortar and add paraffin. The ratio of mixed dry powder to paraffin is 5:1.

[0113] The dry powder and paraffin are mixed by rolling in a mortar to obtain a mixed wet material.

[0114] The mixed wet material was sieved with 60# and then placed in an oven to dry for 12 hours to obtain a shaped abrasive.

[0115] The shaped abrasive is poured into the mold and hot pressed at 120°C for 10 min at a pressure of 2 MPa.

[0116] The pressed molded cutter head is placed in a sintering furnace for sintering at a sintering temperature of 650°C.

[0117] Use epoxy resin adhesive to bond the cutter head to the groove of the substrate, ensuring that the distance between the cutter heads is equal and the side faces are perpendicular to the substrate surface;

[0118] After bonding, the grinding wheel is ground on the end face of the grinding wheel head by a surface grinder.

[0119] Under this process condition, the prepared 2000# grinding wheel can achieve a wear ratio (workpiece: grinding wheel) greater than 4: 1. The grinding process is stable, the surface quality of the workpiece after grinding is excellent, there are no scratches, and the surface roughness after grinding is Ra<14nm.

[0120] Embodiment 4:

[0121] This example uses 8000# diamond powder to prepare wafer thinning superhard grinding wheels. The specific process and preparation process are as follows:

[0122] First of all, the mass percentage ratio of specific raw materials is obtained through simulation experiments, including silicon dioxide: 45%, boron oxide: 20%, aluminum oxide: 18%, potassium oxide: 5%, sodium oxide: 4%, titanium oxide: 3%, phosphorus pentoxide: 1%, and mixture: 4%. The raw materials are evenly mixed by ball milling and sieved to obtain a mixed powder. After the mixed powder is melted, it is dripped into deionized water, dried, and ball milled for 3 hours to obtain ceramic binder powder. The ceramic binder is sieved through a 600# sieve.

[0123] Preparation of composite pore-forming agent: hollow glass balls, sodium bicarbonate and dizodicarbonyl were weighed in a ratio of 3:1:2, respectively, sodium bicarbonate and dizodicarbonyl were dissolved in ethanol, ultrasonically mixed for 30 minutes, and dried in an oven. Then, hollow glass balls were added, and the mixture was milled in a ball mill for 4 hours. The composite pore-forming agent was sieved through a 200# sieve.

[0124] Weigh the diamond abrasive 40%, the ceramic binder 25%, the pore-forming agent 31%, and the additive 4% by mass. Mix the diamond abrasive, the ceramic binder, and the pore-forming agent, put them into a three-dimensional mixer and mix them for 2 hours, then add the additive hexagonal boron nitride, and continue mixing for 2 hours to obtain a mixed dry powder.

[0125] Put the mixed dry powder into a mortar and add paraffin. The ratio of mixed dry powder to paraffin is 6:1.

[0126] The dry powder and paraffin are mixed by rolling in a mortar to obtain a mixed wet material.

[0127] The mixed wet material was sieved with 60# and then placed in an oven for drying for 15 hours to obtain a shaped abrasive.

[0128] The shaped abrasive is poured into the mold and hot pressed at 120°C for 10 min at a pressure of 2 MPa.

[0129] The pressed molded cutter head is placed in a sintering furnace for sintering at a sintering temperature of 800°C.

[0130] Use epoxy resin adhesive to bond the cutter head to the groove of the substrate, ensuring that the distance between the cutter heads is equal and the side faces are perpendicular to the substrate surface;

[0131] After bonding, the grinding wheel is ground on the end face of the grinding wheel head by a surface grinder.

[0132] Under this process condition, the prepared 8000# grinding wheel can achieve a wear ratio (workpiece: grinding wheel) greater than 2.5: 1. The grinding process is stable, and the wear marks of the rough grinding process can be effectively removed to obtain a uniform and high surface quality, and the surface roughness after grinding is Ra <10nm.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a precision machining tool for thinning a silicon carbide wafer, characterized in that: The method comprises the following steps: S1. Determine the particle size and ratio of diamond abrasive, pore former, ceramic binder, the ratio of additives and target porosity, verify the target porosity through simulation experiments, and adjust the ratio of each raw material; S2. preparing a ceramic binder sample and obtaining its thermal expansion coefficient, and optimizing the composition of the ceramic binder according to the thermal expansion coefficient of the diamond abrasive; S3, preparing a ceramic binder and a pore-forming agent, and preparing each raw material into a mixed dry powder and adding paraffin wax, rolling and mixing the mixed dry powder to obtain a mixed wet material, and finally sieving and drying the mixed wet material to obtain a shaped abrasive; S4, pouring the formed abrasive into the mold, hot pressing it into a cutter head and sintering it, and using a binder to bond the cutter head to the groove of the base, and finally grinding the grinding wheel cutter head.

2. The method for preparing a precision machining tool for thinning a silicon carbide wafer according to claim 1, characterized in that: The step of determining the particle size and ratio of diamond abrasive, pore former, and vitrified binder, the ratio of additives, and target porosity, verifying the target porosity through simulation experiments, and adjusting the ratio of each raw material includes the following steps: S11, determine the particle size and ratio of diamond abrasive, pore former, ceramic binder, the ratio of additives and the target porosity, and construct the geometric shape of each raw material in ANSYS simulation software, and at the same time construct the initial microstructure geometric model of the abrasive tool based on the ratio of each raw material; S12, assigning corresponding properties to each raw material, and simulating its internal mechanical behavior and pore structure formation process, and finally meshing the constructed geometric model to generate a finite element mesh. At the same time, according to the actual preparation method, the corresponding pressure load is applied in the simulation model to observe the movement of particles and the change of pore structure; S13. After the simulation experiment is completed, the microstructure image of the mold is obtained, and the image is analyzed using image processing technology to distinguish between pores and solid phases. Finally, the porosity of the simulation model is obtained by calculating the ratio of the area or volume of the pore region to the total volume. The calculated simulation porosity is compared with the target porosity. When the porosity is within the error range of ±1%, it means that the current proportion of each raw material meets the requirements. When the error range exceeds ±1%, the component proportion of each raw material is adjusted.

3. The method for preparing a precision machining tool for thinning a silicon carbide wafer according to claim 1, characterized in that: The calculated simulated porosity is compared with the target porosity. When the porosity is within the error range of ±1%, it means that the current proportion of each raw material meets the requirements. When the error range exceeds ±1%, adjusting the proportion of each raw material includes the following steps: S131. Calculate the porosity. The specific formula is: Where p is the calculated porosity, D1 and D2 are the volume of the pore area and the total volume, respectively; When the error range exceeds ±1%, the simulation experiment parameters are adjusted to obtain data to establish a mathematical model of porosity and the percentage of diamond abrasive, pore former, and ceramic binder. The formula is: P1=P0+α·B1-β·B2-γ·B3; Among them, P1 is the actual porosity, P0 is the porosity without diamond and pore-forming agent, α is the enhancement coefficient of pore-forming agent on porosity, β is the inhibition coefficient of diamond on porosity, γ is the inhibition coefficient of binder on porosity, B1, B2, B3 are the percentage of pore-forming agent, percentage of diamond abrasive, and percentage of vitrified binder, respectively; Calculate the porosity difference that needs to be increased or decreased and establish the equation system: ΔP=α·ΔB1-β·ΔB2-γ·ΔB3; 0 = ΔB1 + ΔB2 + ΔB3; Solve the equation group, and set the adjustment weight w1 of the pore former to be the highest, the weight w2 of the ceramic binder to be the second, and the weight w3 of the pore former to be the third, to obtain the adjustment ratio of each raw material; A secondary simulation experiment is conducted on the ratio of each raw material to verify the porosity. When the porosity is within the normal range, the raw material ratio is output. When the porosity exceeds the normal range, the ratio of each raw material is further adjusted.

4. The method for preparing a precision machining tool for thinning a silicon carbide wafer according to claim 1, characterized in that: The specific steps of preparing a ceramic binder sample and obtaining its thermal expansion coefficient, and optimizing the composition of the ceramic binder according to the thermal expansion coefficient of the diamond abrasive are: S21. Prepare a small amount of ceramic binder sample, weigh by mass percentage, silicon dioxide: 45% to 55%, boron oxide: 15% to 25%, aluminum oxide: Al2O3, potassium oxide: 3% to 7%, sodium oxide: 2% to 5%, titanium oxide: 2% to 4%, phosphorus pentoxide: 1% to 2%, ball mill to mix evenly, sieve to obtain a mixed powder, drip the mixed powder into deionized water after melting, dry, ball mill for 1 hour to obtain ceramic binder powder, sieve through a 600# sieve to obtain a sample; S22, preset a difference range of thermal expansion coefficients of diamond abrasive and ceramic binder, and obtain the thermal expansion coefficient of ceramic binder, compare the thermal expansion coefficients of ceramic binder and diamond abrasive, and directly proceed to the next step of mixing when they do not exceed the preset range, and when they exceed the preset range, prepare a mixture and add it to the ceramic binder so that the thermal expansion coefficient of the ceramic binder is within the preset range.

5. The method for preparing a precision machining tool for thinning a silicon carbide wafer according to claim 4, characterized in that: When the thermal expansion coefficient of the ceramic binder exceeds the preset range, preparing the mixture and adding the ceramic binder so that the thermal expansion coefficient of the ceramic binder is within the preset range comprises the following steps: S221. When the thermal expansion coefficient of the ceramic binder exceeds a preset range, a mixture of eucryptite and zirconium oxide composite powders is prepared, wherein the ratio of eucryptite to zirconium oxide is 7:3, a small amount of the mixture is added to the sample, and the thermal expansion coefficient of the sample is verified; S222. Calculate the amount of composite powder added based on the difference in thermal expansion coefficients, and modify the raw materials of the ceramic binder. The specific raw materials are silicon dioxide: 45% to 55%, boron oxide: 15% to 25%, aluminum oxide: Al2O3, potassium oxide: 3% to 7%, sodium oxide: 2% to 5%, titanium oxide: 2% to 4%, phosphorus pentoxide: 1% to 2%, and mixture: 3% to 5%.

6. The method for preparing a precision machining tool for thinning a silicon carbide wafer according to claim 1, characterized in that: The preparation of the ceramic binder and the pore-forming agent, preparing the raw materials into a mixed dry powder and adding paraffin wax, rolling and mixing the raw materials to obtain a mixed wet material, and finally sieving and drying the mixed wet material to obtain a shaped abrasive comprises the following steps: S31, prepare a pore-forming agent, weigh hollow glass balls, sodium bicarbonate and dizodicarbonyl in a ratio of 3:1:2, dissolve sodium bicarbonate and dizodicarbonyl in ethanol, mix them evenly by ultrasonication for 30 minutes, put them in an oven for drying, then add the hollow glass balls, ball mill them for 3 hours, and sieve through a 200# sieve to obtain a composite pore-forming agent; S32, preparing a ceramic binder, ball-milling raw materials of the ceramic binder to mix evenly, sieving to obtain a mixed powder, melting the mixed powder and dropping it into deionized water, drying, ball-milling for 1 hour to obtain a ceramic binder powder, and sieving through a 600# sieve to obtain a ceramic binder; S33, mixing the diamond abrasive, the ceramic binder and the pore-forming agent in a three-dimensional mixer for 1-2 hours, adding the hexagonal boron nitride additive, and continuing to mix for 1-2 hours to obtain a mixed dry powder; S34. Put the mixed dry powder into a mortar and add paraffin. The ratio of the mixed dry powder to the paraffin is (5-6):

1. Use the mortar to mix the dry powder and the paraffin by rolling to obtain a mixed wet material. After sieving the mixed wet material with 60#, put it into an oven and dry it for 10-15 hours to obtain a shaped abrasive.

7. The method for preparing a precision machining tool for thinning a silicon carbide wafer according to claim 1, characterized in that: The step of pouring the shaped abrasive into the grinding tool, hot pressing it into a cutter head, sintering it, and bonding the cutter head to the groove of the base body with a binder, and finally grinding the grinding wheel cutter head comprises the following steps: S41, set the pressure to 2-8Mpa, pour the formed abrasive into the mold and hot press at 120℃ for 10-15min, finally put the pressed formed cutter head into a sintering furnace for sintering at a sintering temperature of 550℃-850℃; S42, bonding the cutter heads to the grooves of the substrate using an epoxy resin adhesive, and ensuring that the cutter heads are spaced evenly apart and the sides are perpendicular to the surface of the substrate; S43. Use a surface grinder to grind the end face of the grinding wheel cutter.

8. A device for preparing a precision machining tool for thinning a silicon carbide wafer, characterized in that: The device is used in the preparation of precision machining tools for thinning silicon carbide wafers, and includes a memory and a processor: a memory for non-transitory storage of computer readable instructions; A processor, configured to execute the computer-readable instructions; wherein, when the computer-readable instructions are executed by the processor, the method described in any one of claims 1 to 7 is executed.

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