Wafer thinning ceramic-based diamond grinding wheel and preparation method and application thereof

Abstract

The application discloses a ceramic-based diamond grinding wheel for wafer thinning and a preparation method and application thereof, and comprises ceramic grinding blocks arranged on an aluminum alloy base; the ceramic grinding blocks comprise 20-40% of ceramic binder, 20-40% of diamond micro powder and 30-50% of pore-forming agents in percentage by mass; the ceramic binder comprises 25-50% of silicon oxide, 20-40% of boron oxide, 6-15% of sodium oxide, 6-10% of aluminum oxide, 5-7% of zinc oxide, 4-6% of zirconium oxide, 3-5% of calcium oxide, 1-3% of magnesium oxide, 1-3% of potassium oxide and 0.5-4% of lithium oxide in percentage by mass. The application introduces lithium oxide and zirconium oxide, reduces the local stress of the ceramic binder and diamond compound, and improves the binding force; sodium oxide and potassium oxide are used in cooperation to reduce the ceramic sintering temperature, and the application effectively improves the service performance of the grinding wheel and the production yield.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor processing technology, specifically relating to a ceramic-based diamond grinding wheel for wafer thinning, its preparation method, and its application. Background Technology

[0002] The effective thickness of the circuit layer on the wafer is 5-10 μm, and approximately 90% of the substrate material is used to ensure sufficient strength of the wafer during processing, testing, and transportation. To reduce the size of the packaged integrated circuit chip and improve its heat dissipation, the back side of the wafer needs to be thinned before packaging to remove excess silicon material from the back side of the wafer.

[0003] Wafer thinning includes rough grinding and fine grinding. Commonly used grinding wheels are ceramic-bonded diamond grinding wheels and resin-bonded diamond grinding wheels. However, resin-bonded diamond grinding wheels, due to their poor rigidity, cannot achieve the required dimensional accuracy after fine grinding, thus limiting their application in fine grinding processes. Ceramic-bonded diamond grinding wheels, using ceramic as a binder to combine with diamond abrasive, are used for silicon wafer processing. They possess good rigidity, chemical stability, self-sharpening properties, and high grinding efficiency, and do not cause ionic contamination to the chip. Therefore, developing high-performance ceramic-bonded composite ultrafine diamond grinding wheels is of great significance.

[0004] However, due to the low heat resistance and low coefficient of thermal expansion of diamond, few ceramic bonding materials can simultaneously match diamond in terms of coefficient of thermal expansion and softening point. Using conventional ceramic binders often results in poor bonding strength, excessive abrasive pull-out, or accumulation of bonding material on the workpiece, causing damage. Furthermore, as surface roughness requirements increase, the particle size of diamond and ceramic binders gradually decreases, making them prone to agglomeration and sintering cracking, leading to uneven mixing and low yield of grinding blocks. Summary of the Invention

[0005] To address the technical challenges of improving the surface quality of thinned silicon wafers and enabling the mass production of grinding blocks in a uniform and stable manner, this invention aims to provide a ceramic-based diamond grinding wheel for wafer thinning, along with its preparation method and application. This method can effectively improve the yield, mechanical properties, and grinding performance of the grinding wheel.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A ceramic-bonded diamond grinding wheel for wafer thinning includes a ceramic grinding block and an aluminum alloy substrate, wherein the ceramic grinding block is disposed on the aluminum alloy substrate; the ceramic grinding block comprises, by weight percentage, 20%-40% ceramic binder, 20%-40% diamond powder and 30%-50% pore-forming agent.

[0008] The ceramic binder comprises, by weight percentage, 25%-50% silicon dioxide, 20%-40% boron oxide, 6%-15% sodium oxide, 6%-10% aluminum oxide, 5%-7% zinc oxide, 4%-6% zirconium oxide, 3%-5% calcium oxide, 1%-3% magnesium oxide, 1%-3% potassium oxide and 0.5%-4% lithium oxide.

[0009] Furthermore, the ceramic binder is prepared by mixing ceramic binder powders with particle sizes of 0.1-1.5μm and 8-10μm at a mass ratio of 1-3:1.

[0010] Furthermore, the pore-forming agent is one or more of polystyrene microspheres, polymethyl methacrylate microspheres, carbon particles, and naphthalene.

[0011] Furthermore, diamond micro powder is a powder with a particle size of 0.25-3μm obtained by crushing synthetic diamond single crystals.

[0012] A method for preparing a ceramic-based diamond grinding wheel for wafer thinning includes the following steps:

[0013] By mass percentage, 25%-50% silicon dioxide, 20%-40% boron oxide, 6%-15% sodium oxide, 6%-10% aluminum oxide, 5%-7% zinc oxide, 4%-6% zirconium oxide, 3%-5% calcium oxide, 1%-3% magnesium oxide, 1%-3% potassium oxide, and 0.5%-4% lithium oxide are heated to melt and held at that temperature, then cooled and pulverized to obtain micron-sized ceramic binder powders of different particle sizes.

[0014] A ceramic binder is obtained by mixing micron-sized ceramic binder powders of different particle sizes;

[0015] Weigh out 20%-40% ceramic binder, 20%-40% diamond micro powder and 30%-50% pore-forming agent by weight percentage;

[0016] The ceramic binder is wet-mixed with diamond micro powder and then dried. It is then mixed with pore-forming agent and binder, granulated, dry-pressed, and sintered to obtain ceramic grinding blocks.

[0017] By placing ceramic grinding blocks on an aluminum alloy substrate, a ceramic-based diamond grinding wheel for wafer thinning is obtained.

[0018] Furthermore, the particle size of the ceramic binder powder is 0.1-1.5μm and 8-10μm, and the mass ratio of the 0.1-1.5μm and 8-10μm ceramic binder powders is 1-3:1.

[0019] Furthermore, when wet mixing the ceramic binder with the diamond micro powder, a wet mixing method is adopted, which involves mixing at 30-50 Hz for 2-4 hours.

[0020] When drying the ceramic binder and diamond micro powder after wet mixing, a combination of magnetic stirring heating and industrial hot air blowing is used for drying; and triolein or triethyl phosphate is added to the mixture of ceramic binder and diamond micro powder, with the amount of triolein or triethyl phosphate added being 2%-6% of the total mass of ceramic binder, diamond powder and pore-forming agent.

[0021] Furthermore, the temperature of the heating table is 70-80℃, and the temperature of the hot air blower is 80-120℃.

[0022] Furthermore, the sintering temperature is 650-680℃, and the time is 2-3h; the total mass ratio of ceramic binder, diamond micro powder and pore-forming agent to the mass ratio of binder is 1:0.15-0.2.

[0023] The application of a ceramic diamond grinding wheel for wafer thinning as described above, or a ceramic diamond grinding wheel for wafer thinning prepared by the method described above, in the thinning of wafer materials for semiconductor compound wafers or electronic components.

[0024] Compared with the prior art, the beneficial technical effects of the present invention are:

[0025] This invention uses a low-melting-point ceramic binder formulation with good compatibility with diamond. Lithium oxide and zirconium oxide are introduced into the ceramic binder to adjust the thermal expansion coefficient of the ceramic binder to match that of diamond, reduce the local stress of the ceramic binder and diamond composite, and improve the bonding strength. The ceramic binder does not contain lead and is a non-toxic and pollution-free green raw material.

[0026] Because the high temperatures during ceramic sintering can easily damage the grinding quality of diamond, sodium oxide and potassium oxide work synergistically to lower the ceramic sintering temperature and reduce the binder softening point to 650℃. Therefore, the prepared grinding block green body can be sintered and formed at a temperature that does not damage the diamond. In this invention, the ceramic grinding block directly participates in the wafer grinding, playing a crucial role. By adjusting the composition of the ceramic binder, the bonding force between the ceramic binder and diamond is significantly improved, and the sintering temperature is lowered, reducing high-temperature damage to the diamond. A special mixing process ensures uniform material mixing, significantly reducing surface damage during grinding. This invention effectively improves the performance of the grinding wheel and the production yield, and is easy to scale up for production and application.

[0027] Furthermore, this invention achieves a synergistic improvement in the mechanical properties and yield of the grinding blocks by adjusting the gradation of the ceramic binder. Adjusting the blending of coarse and fine ceramic binder powders allows the grinding blocks to simultaneously possess good mechanical properties and a high yield.

[0028] Furthermore, the mixing method of this invention differs from conventional dry mixing. It adopts anhydrous ethanol wet mixing method, and adds a certain amount of trioleic acid glyceride or triethyl phosphate as a dispersant. The drying time after discharge is short, which effectively reduces the agglomeration of diamond micro powder and ceramic powder, improves the surface quality of wafer after thinning, and makes it less likely for deep scratches to appear on the wafer surface.

[0029] Furthermore, compared with ordinary drying methods, the drying process that combines magnetic stirring and heating with an industrial hot air blower after mixing can avoid the stratification of diamond and ceramic binder due to their different densities during the drying process, and the powder is evenly mixed after drying. Attached Figure Description

[0030] Figure 1 SEM images of diamond bonding with different ceramic binders are shown; (a) is Example 1, and (b) is Comparative Example 6.

[0031] Figure 2 This is a SEM image of the cross-sectional microstructure of the grinding block sample from Example 1.

[0032] Figure 3 SEM images of the scratches on the wafer surface caused by the grinding wheels of Example 1 and Comparative Example 7 are shown; where (a) is Example 1 and (b) is Comparative Example 7.

[0033] Figure 4 The images show SEM and AFM roughness maps of the silicon wafer surface after grinding in Example 1; where (a) is the SEM image and (b) is the AFM roughness map.

[0034] Figure 5 A photograph of the actual material used in the preparation of the grinding wheel. Detailed Implementation

[0035] To better understand the present invention, the following examples further illustrate the content of the present invention, but the present invention is not limited to the following embodiments.

[0036] The present invention provides a method for preparing a high-strength, high-grinding-performance ceramic-based diamond grinding wheel for wafer thinning, comprising the following steps:

[0037] (1) Preparation of ceramic binder; the specific process is as follows:

[0038] Weigh out 25%-50% silicon dioxide, 20%-40% boron oxide, 6%-15% sodium oxide, 6%-10% aluminum oxide, 5%-7% zinc oxide, 4%-6% zirconium oxide, 3%-5% calcium oxide, 1%-3% magnesium oxide, 1%-3% potassium oxide and 0.5%-4% lithium oxide by mass percentage, heat to 1400℃ to melt and keep at that temperature for 4-5 hours;

[0039] The binder material obtained by high-temperature heating is rapidly cooled to room temperature in water;

[0040] The raw materials after rapid cooling were ball-milled for 8-12 hours and 1-2 hours respectively to obtain ceramic binder powders with particle sizes of 0.1-1.5 μm and 8-10 μm.

[0041] (2) The ceramic binder powders of different particle sizes are compounded, and the mass ratio of 0.1-1.5μm and 8-10μm ceramic binder powder is 1-3:1 to obtain ceramic binder. Weigh 20%-40% ceramic binder, 20%-40% diamond micro powder and 30%-50% pore-forming agent by mass percentage.

[0042] The ceramic binder and diamond powder are wet-mixed mechanically to obtain a mixed slurry. The specific process is as follows: the mixing is carried out by wet mechanical mixing at 30-50 Hz for 2-4 hours. The mixing is wet mixing, and anhydrous ethanol is used as the mixing medium. The ratio of raw materials to anhydrous ethanol is 1:1.5-2. 2%-6% of trioleic acid glyceride or triethyl phosphate is added to the total mass of ceramic binder, diamond powder and pore-forming agent.

[0043] (3) The mixed slurry is heated by magnetic stirring and industrial hot air blower. The temperature of the heating table is 70-80℃, the stirring speed is 500r / min, and the temperature of the industrial hot air blower is 80-120℃. After drying, it is mixed with pore-forming agent and binder, granulated, dry-pressed, and sintered at 650-680℃ for 2-3 hours to obtain grinding blocks.

[0044] The binder is one or more of the following: a 1 wt% aqueous solution of dextrin, an aqueous solution of polyvinyl alcohol, an aqueous solution of hydroxypropyl methylcellulose, and an aqueous solution of carboxymethylcellulose.

[0045] The mass ratio of powder raw materials (ceramic binder, diamond micro powder and pore-forming agent) to binder is 1:0.15-0.2.

[0046] (4) Adhere the grinding block to the aluminum alloy substrate.

[0047] Specifically, one of epoxy resin, polyurethane, and silicone potting compound is used for bonding.

[0048] The ceramic-based diamond grinding wheel prepared by this invention can be used for thinning of wafer materials such as silicon wafers and other semiconductor compound wafers and electronic components.

[0049] Example 1

[0050] A mixture of 43.5% silicon dioxide, 25% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, 1% potassium oxide, and 1.5% lithium oxide by mass percentage was heated to melt and held at that temperature for 4 hours. The mixture was then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed at a mass ratio of 1:2 as the ceramic binder.

[0051] The ceramic binder and diamond powder were mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) was added, and the mixture was mixed in a mixer at 40 Hz for 3 hours.

[0052] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 75℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 100℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0053] The grinding block is bonded to the aluminum alloy substrate with potting compound, and after flatness adjustment and dynamic balancing, a high-strength, high-grinding-performance ceramic-based diamond grinding wheel for wafer thinning is obtained.

[0054] The microstructure of the scratches and the surface roughness of the silicon wafer were tested by using a thinning machine to test the silicon wafer.

[0055] Example 2

[0056] A mixture of 25% silicon dioxide, 40% boron oxide, 6.5% sodium oxide, 10% aluminum oxide, 7% zinc oxide, 4% zirconium oxide, 5% calcium oxide, 1% magnesium oxide, 1% potassium oxide, and 0.5% lithium oxide by mass percentage was heated to melt and held at that temperature for 4 hours. The mixture was then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 1 hour and 8 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed in a 1:1 mass ratio as the ceramic binder.

[0057] The ceramic binder, diamond micro powder, and anhydrous ethanol were placed in a mixing tank, and 2% of the total mass of the ceramic binder, diamond micro powder, and pore-forming agent (trioleyl glyceride) was added. The mixture was then mixed in a mixer at 30 Hz for 4 hours.

[0058] A magnetic stirring heating system combined with an industrial hot air blower was used. The heating table temperature was 70℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were, by mass percentage, 35% ceramic binder, 35% diamond micron powder, and 30% pore-forming agent; the total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15, and the binder was a dextrin aqueous solution.

[0059] The grinding block is bonded to the aluminum alloy substrate with potting compound, and after flatness adjustment and dynamic balancing, a high-strength, high-grinding-performance ceramic-based diamond grinding wheel for wafer thinning is obtained.

[0060] Example 3

[0061] A mixture of 50% silicon dioxide, 20% boron oxide, 6% sodium oxide, 6% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, 3% potassium oxide, and 2% lithium oxide by mass percentage was heated to melt and held at that temperature for 4 hours. The mixture was then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 10 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed at a mass ratio of 1:2 as the ceramic binder.

[0062] The ceramic binder, diamond micro powder, and anhydrous ethanol were placed in a mixing tank, and 3% of trioleic acid glyceride (based on the total mass of the ceramic binder, diamond micro powder, and pore-forming agent) was added. The mixture was then mixed in a mixer at 50 Hz for 2 hours.

[0063] A magnetic stirring heating system was used in conjunction with an industrial hot air blower. The heating table temperature was 80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.2. The binder was an aqueous solution of polyvinyl alcohol.

[0064] The grinding block is bonded to the aluminum alloy substrate with potting compound, and after flatness adjustment and dynamic balancing, a high-strength, high-grinding-performance ceramic-based diamond grinding wheel for wafer thinning is obtained.

[0065] Example 4

[0066] A mixture of 25% silicon dioxide, 27% boron oxide, 15% sodium oxide, 10% aluminum oxide, 6% zinc oxide, 6% zirconium oxide, 4% calcium oxide, 2% magnesium oxide, 1% potassium oxide, and 4% lithium oxide by mass percentage was heated to melt and held at that temperature for 4 hours. The mixture was then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 1.5 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed at a mass ratio of 1:3 as the ceramic binder.

[0067] The ceramic binder, diamond micro powder, and anhydrous ethanol were placed in a mixing tank, and 4% of the total mass of the ceramic binder, diamond micro powder, and pore-forming agent was added as trioleic acid glyceride. The mixture was then mixed in a mixer at 35 Hz for 3 hours.

[0068] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 75℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 670℃ for 2.5 h to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 20%, and pore-forming agent 45%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.17. The binder was an aqueous solution of hydroxypropyl methylcellulose.

[0069] The grinding block is bonded to the aluminum alloy substrate with potting compound, and after flatness adjustment and dynamic balancing, a high-strength, high-grinding-performance ceramic-based diamond grinding wheel for wafer thinning is obtained.

[0070] Example 5

[0071] A mixture of 40% silicon dioxide, 20% boron oxide, 12% sodium oxide, 8% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 4% calcium oxide, 3% magnesium oxide, 2% potassium oxide, and 2% lithium oxide by mass percentage was heated to melt and held at that temperature for 4 hours. The mixture was then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed at a mass ratio of 1:1.5 as the ceramic binder.

[0072] The ceramic binder, diamond micro powder, and anhydrous ethanol were placed in a mixing tank, and 5% of the total mass of the ceramic binder, diamond micro powder, and pore-forming agent was added as triethyl phosphate. The mixture was then mixed in a mixer at 45 Hz for 2 hours.

[0073] A magnetic stirring heating system combined with an industrial hot air blower was used. The heating table temperature was 70℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 110℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 3 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 40%, diamond micron powder 25%, and pore-forming agent 35%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15. The binder was a mixture of dextrin aqueous solution and polyvinyl alcohol aqueous solution.

[0074] The grinding block is bonded to the aluminum alloy substrate with potting compound, and after flatness adjustment and dynamic balancing, a high-strength, high-grinding-performance ceramic-based diamond grinding wheel for wafer thinning is obtained.

[0075] Comparative Example 1 (Fine powder only)

[0076] The binder material is prepared by mixing 43.5% silicon dioxide, 25% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, 1% potassium oxide and 1.5% lithium oxide by mass percentage, heating to melt and holding at that temperature for 4 hours, and then rapidly cooling to room temperature. The rapidly cooled raw material is then ball-milled for 12 hours to be used as a ceramic binder (0.1-1.5 μm).

[0077] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) is added, and the mixture is mixed in a mixer at 30-50 Hz for 2-4 hours.

[0078] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 70-80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80-120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0079] Comparative Example 2 (without zirconium oxide)

[0080] The following ingredients, by mass percentage: 46% silicon dioxide, 26.5% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 3% calcium oxide, 1% magnesium oxide, 1% potassium oxide, and 1.5% lithium oxide, are heated to melt and held at that temperature; then rapidly cooled to room temperature. The cooled raw material is then divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B are mixed at a mass ratio of 1:2 as the ceramic binder.

[0081] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) is added, and the mixture is mixed in a mixer at 30-50 Hz for 2-4 hours.

[0082] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 70-80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80-120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0083] Comparative Example 3 (Lithium Oxide-Free)

[0084] A mixture of 44.5% silicon dioxide, 25.5% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, and 1% potassium oxide by mass percentage was heated to melt and held at that temperature, then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed in a mass ratio of 1:2 as the ceramic binder.

[0085] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) is added, and the mixture is mixed in a mixer at 30-50 Hz for 2-4 hours.

[0086] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 70-80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80-120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 670℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0087] Comparative Example 4 (without potassium oxide)

[0088] A mixture of 45% silicon dioxide, 25% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, and 1% lithium oxide by mass percentage was heated to melt and held at that temperature. The mixture was then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed in a mass ratio of 1:2 as the ceramic binder.

[0089] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) is added, and the mixture is mixed in a mixer at 30-50 Hz for 2-4 hours.

[0090] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 70-80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80-120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 710℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0091] Comparative Example 5 (Sodium-free)

[0092] A mixture of 50% silicon dioxide, 25% boron oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 3% potassium oxide, 2% magnesium oxide, and 1% lithium oxide by mass percentage was heated to melt and held at that temperature. The melt was then rapidly cooled to room temperature. The cooled raw material was divided into two portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed in a 1:2 mass ratio as the ceramic binder.

[0093] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) is added, and the mixture is mixed in a mixer at 30-50 Hz for 2-4 hours.

[0094] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 70-80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80-120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 690℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0095] Comparative Example 6 (Oven Drying)

[0096] A mixture of 43.5% silicon dioxide, 25% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, 1% potassium oxide, and 1.5% lithium oxide by mass percentage was heated to melt and held at that temperature, then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powder A (8-10 μm) and powder B (0.1-1.5 μm) with different particle sizes. Powder A and powder B were mixed in a mass ratio of 1:2 as the ceramic binder.

[0097] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank. 5% of the total mass of the ceramic binder, diamond powder, and pore-forming agent (trioleic acid glyceride) is added, and the mixture is mixed in a mixer at 30-50 Hz for 2-4 hours.

[0098] The mechanically mixed slurry was dried in a forced-air drying oven at 80℃. After drying, the material showed obvious stratification, with ceramic binder powder on top and diamond powder on the bottom. The powder was then ground into a fine powder, mixed with a pore-forming agent and binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond powder, and pore-forming agent to the binder was 1:0.15; the binder was a dextrin aqueous solution.

[0099] The grinding block is bonded to the aluminum alloy substrate with potting compound, and the grinding wheel product is obtained after flatness adjustment and dynamic balancing.

[0100] The microstructure of the scratches and the surface roughness of the silicon wafer were tested by using a thinning machine to test the silicon wafer.

[0101] Comparative Example 7 (Purchased Ceramic Binder)

[0102] Purchased ceramic binder D1 was used as raw material. The particle size of the purchased ceramic binder was found to be similar to that of powder A, as measured by a laser particle size analyzer. The ceramic binder was ball-milled for 8 hours to obtain a fine powder with a particle size similar to that of powder B. Powder A and powder B were mixed in a 1:2 mass ratio as the ceramic binder.

[0103] The ceramic binder and diamond powder are mixed in a mass ratio of 1:1 with anhydrous ethanol in a mixing tank, and 5% trioleic acid glyceride is added. The mixture is then mixed in a mixer at 30-50 Hz for 2-4 hours.

[0104] A combination of magnetic stirring heating and an industrial hot air blower was used. The heating table temperature was 70-80℃, the stirring speed was 500 r / min, and the industrial hot air blower temperature was 80-120℃. After drying, the powder was ground into a fine powder that was uniform and free of lumps. Subsequently, it was mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 750℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond micron powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond micron powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond micron powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0105] The grinding block is bonded to the aluminum alloy substrate with potting compound, and the grinding wheel product is obtained after flatness adjustment and dynamic balancing.

[0106] The microstructure of the scratches and the surface roughness of the silicon wafer were tested by using a thinning machine to test the silicon wafer.

[0107] Comparative Example 8 (dry mix)

[0108] A mixture of 43.5% silicon dioxide, 25% boron oxide, 9% sodium oxide, 7% aluminum oxide, 5% zinc oxide, 4% zirconium oxide, 3% calcium oxide, 1% magnesium oxide, 1% potassium oxide, and 1.5% lithium oxide by mass percentage was heated to melt and held at that temperature, then rapidly cooled to room temperature. The cooled raw material was divided into two equal portions and ball-milled for 2 hours and 12 hours respectively to obtain ceramic binder powders A and B with different particle sizes. Powder A and powder B were mixed in a mass ratio of 1:2 as the ceramic binder.

[0109] The ceramic binder and diamond powder were mixed evenly at a mass ratio of 1:1, then mixed with a pore-forming agent and a binder, granulated, dry-pressed, and sintered at 650℃ for 2 hours to obtain ceramic grinding blocks. The ceramic binder, diamond powder, and pore-forming agent were distributed as follows by mass percentage: ceramic binder 35%, diamond powder 35%, and pore-forming agent 30%. The total mass ratio of the ceramic binder, diamond powder, and pore-forming agent to the binder was 1:0.15; the binder was an aqueous dextrin solution.

[0110] The grinding block is bonded to the aluminum alloy substrate with potting compound, and the grinding wheel product is obtained after flatness adjustment and dynamic balancing. The microstructure of the scratches on the silicon wafer and the surface roughness of the silicon wafer are tested by grinding the silicon wafer with a thinning machine.

[0111] The performance comparison of the ceramic grinding blocks prepared in the examples and comparative examples is shown in Table 1.

[0112] Table 1 Comparison of Material Properties

[0113]

[0114] (1) As can be seen from Example 1 and Comparative Example 1 in Table 1, by combining coarse and fine ceramic binders, the occurrence of cracks and deformation after sintering of the grinding block can be effectively improved, while ensuring that the grinding block has high strength and meets the requirements for subsequent processing and use.

[0115] (2) Comparing Example 1 with Comparative Examples 2-5, it can be seen that by adjusting the ceramic binder formula, the sintering temperature and thermal expansion coefficient can be effectively optimized, the damage to diamond caused by high temperature can be reduced, and the thermal expansion coefficients of the binder and diamond can be matched, thereby improving the surface quality of diamond and the interface bonding between the ceramic binder and diamond, increasing the strength of the material, and the diamond can be effectively "detached-exposed" during grinding to improve grinding efficiency.

[0116] (3) Comparing Example 1 and Comparative Example 6, it can be seen that compared with ordinary oven drying, the stirring-heating-blowing drying method can avoid the stratification phenomenon of diamond and ceramic binder due to different densities during the drying process, and the powder is more uniformly mixed after drying.

[0117] (4) Comparison of Example 1 and Comparative Example 7 Figure 1The comparison between (a) and (b) clearly shows that the ceramic binder in Example 1 is more tightly bonded to the diamond, and its hold on the diamond is better than that of the purchased ceramic binder. Therefore, the macroscopic manifestation is that it has higher strength and service life.

[0118] (5) Comparison of Example 1 and Comparative Example 8 Figure 3 The comparison between (a) and (b) clearly shows that the grinding wheel prepared by the dry mixing process has low material strength due to the easy agglomeration of powder and uneven mixing. It also shows abnormal scratches during use and has a large surface roughness of the wafer after grinding.

[0119] Finally, the silicon wafer prepared in Example 1 was thinned using a grinding wheel. No abnormal scratches appeared on the surface of the wafer after grinding, and the surface roughness measured by atomic force microscopy was 6.9 nm. Figure 4 As shown in (a) and (b).

[0120] In this invention, the ceramic grinding block directly participates in the grinding of the wafer, playing a crucial role. By adjusting the composition of the ceramic binder, the bonding force between the ceramic binder and diamond is significantly improved, the sintering temperature is lowered, and high-temperature damage to the diamond is reduced. Adjusting the gradation of the ceramic binder effectively improves the yield of the grinding block. A special mixing process ensures uniform material mixing, significantly reducing surface damage during grinding, making it suitable for large-scale production. Using the above-mentioned improved methods, the performance of the grinding wheel and the production yield can be effectively improved, facilitating large-scale production and application.

[0121] Based on the above content, without departing from the basic technical concept of the present invention, various modifications, substitutions or changes can be made to the content in various forms according to common technical knowledge and means in the field.

Claims

1. A ceramic-based diamond grinding wheel for wafer thinning, characterized in that, It includes a ceramic grinding block and an aluminum alloy substrate, with the ceramic grinding block disposed on the aluminum alloy substrate; the ceramic grinding block comprises, by weight percentage, 20%-40% ceramic binder, 20%-40% diamond micro powder and 30%-50% pore-forming agent; The ceramic binder comprises, by mass percentage, 25%-50% silicon dioxide, 20%-40% boron oxide, 6%-15% sodium oxide, 6%-10% aluminum oxide, 5%-7% zinc oxide, 4%-6% zirconium oxide, 3%-5% calcium oxide, 1%-3% magnesium oxide, 1%-3% potassium oxide, and 0.5%-4% lithium oxide; The ceramic binder is prepared by mixing ceramic binder powders with particle sizes of 0.1-1.5μm and 8-10μm at a mass ratio of 1-3:

1.

2. The ceramic-coated diamond grinding wheel for wafer thinning according to claim 1, characterized in that, The pore-forming agent is one or more of polystyrene microspheres, polymethyl methacrylate microspheres, carbon particles, and naphthalene.

3. The ceramic-coated diamond grinding wheel for wafer thinning according to claim 1, characterized in that, Diamond micro powder is a powder with a particle size of 0.25-3μm obtained by crushing synthetic diamond single crystals.

4. A method for preparing a ceramic-based diamond grinding wheel for wafer thinning, characterized in that, Includes the following steps: By mass percentage, 25%-50% silicon dioxide, 20%-40% boron oxide, 6%-15% sodium oxide, 6%-10% aluminum oxide, 5%-7% zinc oxide, 4%-6% zirconium oxide, 3%-5% calcium oxide, 1%-3% magnesium oxide, 1%-3% potassium oxide and 0.5%-4% lithium oxide are heated to melt and held at that temperature, then cooled and pulverized to obtain micron-sized ceramic binder powders of different particle sizes; A ceramic binder is obtained by mixing micron-sized ceramic binder powders of different particle sizes; the particle sizes of the ceramic binder powders are 0.1-1.5μm and 8-10μm, and the mass ratio of 0.1-1.5μm and 8-10μm ceramic binder powders is 1-3:1; Weigh out 20%-40% ceramic binder, 20%-40% diamond micro powder and 30%-50% pore-forming agent by weight percentage; The ceramic binder is wet-mixed with diamond micro powder and then dried. It is then mixed with pore-forming agent and binder, granulated, dry-pressed, and sintered to obtain ceramic grinding blocks. By placing ceramic grinding blocks on an aluminum alloy substrate, a ceramic-based diamond grinding wheel for wafer thinning is obtained.

5. The method for preparing a ceramic-coated diamond grinding wheel for wafer thinning according to claim 4, characterized in that, When wet mixing ceramic binder with diamond micro powder, a wet mixing method is used, mixing at 30-50 Hz for 2-4 hours. When drying the ceramic binder and diamond micro powder after wet mixing, a combination of magnetic stirring heating and industrial hot air blowing is used for drying; and triolein or triethyl phosphate is added to the mixture of ceramic binder and diamond micro powder, with the amount of triolein or triethyl phosphate added being 2%-6% of the total mass of ceramic binder, diamond powder and pore-forming agent.

6. The method for preparing a ceramic-coated diamond grinding wheel for wafer thinning according to claim 5, characterized in that, The temperature of the heating table is 70-80℃, and the temperature of the hot air blower is 80-120℃.

7. The method for preparing a ceramic-coated diamond grinding wheel for wafer thinning according to claim 4, characterized in that, The sintering temperature is 650-680℃ and the time is 2-3h; the total mass ratio of ceramic binder, diamond micro powder and pore-forming agent to the mass ratio of binder is 1:0.15-0.

2.

8. The application of a ceramic diamond grinding wheel for wafer thinning as described in any one of claims 1-3 or a ceramic diamond grinding wheel for wafer thinning prepared by the method described in any one of claims 4-7 in the thinning of wafer materials for semiconductor compound wafers or electronic components.

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