A processing method of a sapphire substrate

Abstract

The application relates to the technical field of sapphire substrate processing, in particular to a sapphire substrate processing technology, S1, sapphire is cut to obtain sheet-shaped sapphire; S2, a layer of silicon oil is coated on the surface of the sheet-shaped sapphire to obtain pretreated sheet-shaped sapphire; S3, a silk polishing pad is used to coarsely grind both sides of the pretreated sheet-shaped sapphire to obtain coarsely ground sheet-shaped sapphire; S4, a non-woven polishing pad is used to finely grind the coarsely ground sheet-shaped sapphire to obtain finely ground sheet-shaped sapphire; S5, a polyurethane polishing pad is used to chemically and mechanically polish the finely ground sheet-shaped sapphire to obtain polished sheet-shaped sapphire; and S6, the polished sheet-shaped sapphire is soaked in a cleaning liquid, taken out, cleaned with purified water, dried, and sapphire substrate is obtained through a series of fine processing steps, the processing challenge caused by the high hardness and high stability of sapphire material is effectively solved, the sapphire substrate processing efficiency is improved, the processing quality is guaranteed, and the generation of microcracks and scratches is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sapphire substrate processing, and more particularly to a processing technology of sapphire substrate. BACKGROUND

[0002] Sapphire substrate wafers have a wide range of applications in LED manufacturing. Due to its excellent optical transparency and thermal conductivity, sapphire substrate can effectively improve the light output efficiency and heat dissipation performance of LED. However, with the rapid development of technology, the requirements for sapphire finished products in the LED industry are also becoming increasingly stringent. For example, in order to improve the light-emitting efficiency of LED and reduce the cost, manufacturers have begun to require thinner sapphire substrates in order to reduce the absorption and reflection loss of light, while reducing the cost of materials. In addition, higher requirements have been put forward for the surface quality of sapphire substrate, hoping that the size of surface defects is smaller and the number is less, so as to further reduce the scattering and absorption of light, and improve the light output efficiency and overall performance of LED.

[0003] However, the high hardness and high stability of sapphire material have brought great challenges to processing. Due to its extremely high hardness, traditional processing methods are difficult to maintain high efficiency while ensuring processing quality. For example, mechanical grinding is usually used, that is, diamond grinding wheels and other materials with extremely high hardness are used for grinding. However, due to the extremely high hardness of sapphire, a large amount of heat and stress is easily generated during grinding, resulting in low processing efficiency, and micro-cracks and scratches are easily generated on the surface of the material, affecting the processing quality. SUMMARY

[0004] In order to reduce the micro-cracks and scratches of sapphire in the production process and improve the production efficiency, the present application provides a processing technology of sapphire substrate.

[0005] The present application provides a processing technology of sapphire substrate, which adopts the following technical scheme:

[0006] A processing technology of sapphire substrate, comprising the following preparation steps:

[0007] S1, cutting sapphire to obtain a sapphire wafer;

[0008] S2, coating a layer of silicon oil on the surface of the sapphire wafer to obtain a pretreated sapphire wafer;

[0009] S3, using a silk polishing pad to coarsely grind the pretreated sapphire wafer on both sides to obtain a coarsely ground sapphire wafer, and a coarsely grinding liquid is required during the coarsely grinding process, the coarsely grinding liquid is composed of silicon nitride, silicon dioxide, dispersing agent, surfactant, penetrating agent and water according to the weight ratio of (5-9):(3-5):(2-3):(1-2):(0.5-1):13;

[0010] S4, using non-woven polishing pad to polish the rough grinding sheet-shaped sapphire, to obtain the fine grinding sheet-shaped sapphire, the fine grinding process needs to use fine grinding fluid, the fine grinding fluid is composed of alumina, tungsten carbide, sodium hydroxyethyl cellulose, phosphoric acid carboxylic acid, defoaming agent, stearic acid, suspending agent and water according to the weight ratio of (4-6):(3-5):(2-3):(1-2):(0.5-0.8):(2-3):(2-4):15;

[0011] S5, using polyurethane polishing pad to polish the fine grinding sheet-shaped sapphire, to obtain the polishing sheet-shaped sapphire, the polishing process needs to use polishing fluid, the polishing fluid is composed of silicon nitride, alumina, tris-hydroxymethyl aminomethane, diethylenetriamine pentaacetic acid, polyol fatty acid ester, ricinoleic acid, hydroxyethyl cellulose and water according to the weight ratio of (3-6):(4-6):(1-2):(0.5-1):(2-3):(4-6):(1-2):15;

[0012] S6, the polishing sheet-shaped sapphire is soaked in cleaning fluid, taken out, washed with purified water, dried, to obtain sapphire substrate, the cleaning fluid is composed of oxidizing agent, neopentyl glycol, isopropyl alcohol amine, sodium dodecyl sulfonate and purified water according to the weight ratio of (0.5-1):(3-5):(2-4):(1-3):20.

[0013] By adopting the above technical scheme, through a series of fine processing steps and optimized grinding fluid formula, the processing challenge brought by high hardness and high stability of sapphire material is effectively solved, the processing efficiency of sapphire substrate is improved, the processing quality is guaranteed, the generation of micro-cracks and scratches is reduced, and the cleanliness and dryness of the sapphire substrate are maintained.

[0014] S2 step coats a layer of silicon oil on the surface of sapphire, which may help to reduce heat and stress accumulation in the subsequent grinding process, and may improve the adhesion and uniformity of the abrasive.

[0015] S3 step uses silk polishing pad and specific first grinding fluid for double-sided rough grinding. Silicon nitride and silicon dioxide in the grinding fluid as abrasive can effectively remove a large amount of material on the surface of sapphire, and the addition of dispersant, surfactant and penetrant helps to improve the dispersibility and permeability of the abrasive, reduce heat and stress in the grinding process, and thus reduce the generation of micro-cracks and scratches.

[0016] S4 step uses non-woven polishing pad and second grinding fluid for fine grinding. Alumina and tungsten carbide as finer abrasive can further remove traces left by rough grinding and improve surface quality. At the same time, additives such as sodium hydroxyethyl cellulose in the grinding fluid help to maintain the stability and uniformity of the abrasive, further improving the processing quality.

[0017] The step S5 is a chemical mechanical polishing using a polyurethane polishing pad and a polishing solution. The silicon nitride and the aluminum oxide in the polishing solution act as abrasives, and together with trimethylol aminomethane, diethylenetriamine pentaacetic acid, etc., can form a protective film on the sapphire surface while removing a trace amount of material, achieving an extremely high surface smoothness.

[0018] The specific coarse grinding liquid, fine grinding liquid and polishing liquid used in the present application leave stains on the surface of the sapphire substrate that are difficult to clean, and the specific cleaning liquid in the present application can effectively remove the stains.

[0019] Preferably, the silicon oil is an amino silicon oil.

[0020] By using the above technical solution, the amino silicon oil not only has excellent lubricity and adhesion, but also effectively reduces the direct impact of mechanical grinding on the sapphire surface in the coarse grinding stage, reducing processing damage. At the same time, its good chemical stability can also ensure that it does not react adversely with the grinding liquid or polishing liquid during processing, affecting the processing effect.

[0021] Preferably, the average particle size of the silicon nitride is 50-100 nm, and the average particle size of the silicon dioxide is 20-50 nm.

[0022] By using the above technical solution, the average particle size of the silicon nitride and the average particle size of the silicon dioxide are optimized, ensuring uniform dispersion and efficient use of the abrasive, improving grinding efficiency, while reducing heat and stress accumulation during processing, effectively avoiding micro-cracks and scratches on the sapphire surface. Secondly, the abrasive with this particle size range can form fine and uniform scratches, which helps to quickly remove surface defects and improve the surface smoothness and flatness of the sapphire substrate. In addition, the optimized particle size also enhances the stability and flowability of the grinding liquid, making the grinding process more continuous and uniform, further improving the processing quality.

[0023] Preferably, the average particle size of the aluminum oxide is 20-50 nm, and the average particle size of the tungsten carbide is 50-90 nm.

[0024] By using the above technical solution, the average particle size of the aluminum oxide and the average particle size of the tungsten carbide are optimized, ensuring uniformity and efficiency during grinding, improving processing efficiency and surface quality. Secondly, the small particle size of the aluminum oxide helps to refine the scratches and improve the smoothness of the sapphire surface, while the moderate particle size of the tungsten carbide enhances its ability to remove surface defects. The combination of the two makes the surface of the sapphire substrate more flat and smooth. In addition, this range of optimized particle size also helps to reduce the consumption of the grinding liquid and the wear of the equipment, reducing the processing cost.

[0025] Preferably, the average particle size of the silicon nitride is 5-10 nm, and the average particle size of the aluminum oxide is 10-20 nm.

[0026] By optimizing the average particle size of the silicon nitride and the average particle size of the aluminum oxide, the polishing liquid can penetrate more deeply into the tiny defects on the sapphire surface, improving the machining precision and surface finish. Secondly, the ultra-fine silicon nitride and aluminum oxide particles can form more uniform and delicate scratches during grinding, reducing the depth and number of surface scratches, making the machined sapphire surface smoother and brighter. In addition, the optimization of this particle size range also helps to reduce heat and stress accumulation during grinding, further reducing the generation of micro-cracks and scratches.

[0027] Preferably, the penetrant is obtained by mixing sodium polyacrylate and sodium phosphate according to a weight ratio of 1(3-5).

[0028] By adopting the above technical scheme, the interfacial tension between the grinding liquid and the sapphire material can be effectively reduced, the wettability and permeability of the grinding liquid can be enhanced, and the grinding particles can be more uniformly distributed on the material surface, thereby improving the grinding efficiency.

[0029] Preferably, the suspending agent is composed of polyvinyl alcohol and polyvinylpyrrolidone according to a weight ratio of 1:(2-3).

[0030] By adopting the above technical scheme, the suspending stability of the abrasive particles in the grinding liquid can be improved, the particles can be prevented from settling and agglomerating, and it can be ensured that the abrasive particles can uniformly and continuously act on the surface of the sapphire material during grinding. At the same time, the suspending agent can also effectively improve the rheological properties of the grinding liquid, making it easier to spread and penetrate on the material surface, further improving the grinding efficiency and processing quality.

[0031] Preferably, a cutting liquid is used during the cutting process in step S1, and the cutting liquid is composed of lauryl acid polyethylene glycol ester, sodium isobenzene propyl sulfonate, polyoxyethylene, methyl glycine diacetate trisodium, and water according to a weight ratio of (2-3):(1-2):(2-4):(0.5-1):8.

[0032] The components in the cutting liquid synergistically act to effectively reduce friction and heat during cutting, reduce damage and cracks of the sapphire crystal, and improve cutting efficiency. At the same time, the cutting liquid also has good lubricity and cooling effect, ensuring the flatness and smoothness of the cutting surface, laying a good foundation for subsequent processing steps.

[0033] Preferably, the coarse grinding load in step S2 is 15-25 g / cm 2 , the grinding speed is 45-75 rpm, the coarse grinding liquid flow rate is 50-100 ml / min, and the grinding time is 25-30 min.

[0034] By adopting the above technical solution, the rough grinding load, grinding speed, polishing liquid flow and grinding time are accurately controlled to improve the rough grinding quality and efficiency of the sapphire. The rough grinding load is set in the range of 15-25 g / cm 2 , which ensures the effective contact between the abrasive and the sapphire surface and improves the grinding efficiency; the grinding speed is controlled in the range of 45-75 rpm, which not only ensures the uniformity of grinding, but also avoids the heat accumulation and surface damage caused by high speed; the polishing liquid flow is set to 50-100 ml / min, which ensures sufficient lubrication and cooling during grinding, further reducing the generation of surface scratches and micro-cracks; the grinding time is controlled in the range of 25-30 minutes, which not only ensures sufficient grinding time to remove surface defects, but also avoids excessive wear caused by long grinding time.

[0035] Preferably, the fine grinding load in step S3 is 25-60 g / cm 2 , the grinding speed is 80-120 rpm, the fine grinding liquid flow is 150-250 ml / min, and the grinding time is 10-30 min.

[0036] By adopting the above technical solution, the fine grinding load, grinding speed, polishing liquid flow and grinding time are accurately controlled to improve the fine grinding quality and efficiency of the sapphire, and provide a high-quality processing basis for the subsequent polishing step.

[0037] Preferably, the polishing load in step S4 is 100-150 g / cm 2 , the polishing speed is 100-200 rpm, the polishing liquid flow is 100-200 ml / min, and the polishing time is 120-240 min.

[0038] By adopting the above technical solution, the polishing load, grinding speed, polishing liquid flow and grinding time are accurately controlled to improve the surface quality and processing efficiency of the sapphire, and meet the manufacturing requirements of high-precision optical elements. The polishing load is set in the range of 100-150 g / cm 2 , which ensures sufficient pressure and contact area between the polishing pad and the sapphire, promotes the uniform distribution and efficient action of the polishing agent. The polishing speed is controlled in the range of 100-200 rpm, which not only ensures the efficiency of polishing, but also avoids surface damage caused by high speed. The polishing liquid flow is set to 100-200 ml / min, which ensures the continuous supply of polishing liquid during polishing, effectively reducing the generation of surface scratches and fog-like defects.

[0039] In summary, the present application has the following beneficial effects:

[0040] 1. The application effectively solves the challenges of high hardness and high stability in the processing of sapphire material by optimizing cutting and pretreatment, phased grinding and polishing, chemical mechanical polishing, and cleaning and drying. This scheme improves processing efficiency while ensuring processing quality, reduces the generation of micro-cracks and scratches, and provides an efficient and reliable processing method for the preparation of sapphire substrates. DETAILED DESCRIPTION

[0041] EMBODIMENT

[0042] The amino silicone oil is purchased from Shandong Huachen New Material Co., Ltd., and the model is HC.

[0043] EMBODIMENT 1

[0044] A processing technology of sapphire substrate, comprising the following preparation steps:

[0045] S1, cutting sapphire to obtain a sheet-shaped sapphire;

[0046] S2, coating a layer of silicone oil on the surface of the sheet-shaped sapphire to obtain a pretreated sheet-shaped sapphire;

[0047] S3, using silk polishing pads to coarsely grind the pretreated sheet-shaped sapphire on both sides to obtain a coarsely ground sheet-shaped sapphire, and a coarse grinding liquid is used in the coarse grinding process, and the coarse grinding liquid is composed of silicon nitride, silicon dioxide, dispersing agent (microcrystalline wax), surfactant (Tween), penetrant (sodium polyacrylate) and water in a weight ratio of 5:3:2:1:0.5:13;

[0048] The average particle size of silicon nitride is 50-60 nm, and the average particle size of silicon dioxide is 20-30 nm;

[0049] The coarse grinding load in step S2 is 15 g / cm 2 , the grinding speed is 45 revolutions per minute, the coarse grinding liquid flow is 50 ml / min, and the grinding time is 25 min;

[0050] S4, using non-woven polishing pads to finely grind the coarsely ground sheet-shaped sapphire to obtain a finely ground sheet-shaped sapphire, and a fine grinding liquid is used in the fine grinding process, and the fine grinding liquid is composed of aluminum oxide, tungsten carbide, hydroxyethyl cellulose sodium, phosphoric acid carboxylic acid, defoaming agent (propanol), stearic acid, suspending agent (polyvinyl alcohol) and water in a weight ratio of 4:3:2:1:0.5:2:2:15;

[0051] The average particle size of aluminum oxide is 20-50 nm, and the average particle size of tungsten carbide is 50-90 nm;

[0052] The fine grinding load in step S3 is 25 g / cm 2, the grinding rotation speed is 80 r / min, the fine grinding liquid flow is 150 ml / min, and the grinding time is 10 min;

[0053] S5, the polished flaky sapphire is obtained by chemical mechanical polishing of the fine grinding flaky sapphire by using a polyurethane polishing pad, and a polishing liquid is required in the polishing process, the polishing liquid is composed of silicon nitride, aluminum oxide, tris-hydroxymethyl aminomethyl alcohol, diethylenetriamine pentaacetic acid, polyol fatty acid ester (glycerol fatty acid ester), ricinoleic acid, hydroxyethyl cellulose and water in a weight ratio of 3:4:1:0.5:2:4:1:15;

[0054] The average particle size of the silicon nitride is 5-10 nm, and the average particle size of the aluminum oxide is 10-20 nm;

[0055] The polishing load in step S4 is 100 g / cm 2 , the polishing rotation speed is 100 r / min, the polishing liquid flow is 100 ml / min, and the polishing time is 120 min;

[0056] S6, the polished flaky sapphire is immersed in a cleaning liquid, taken out, washed with purified water, and dried to obtain a sapphire substrate, and the cleaning liquid is composed of an oxidizing agent, neopentyl glycol, isopropanolamine, sodium dodecyl sulfonate and purified water in a weight ratio of 0.5:3:2:1:20.

[0057] Example 2-3 is different from example 1 in that the raw materials, the amount and the experimental parameters of the processing technology of the sapphire substrate are different, and the specific differences are shown in table 1:

[0058]

[0059]

[0060] Example 4

[0061] A processing technology of a sapphire substrate, the difference between this embodiment and example 1 is that the average particle size of the silicon dioxide is 50-60 nm.

[0062] Example 5

[0063] A processing technology of a sapphire substrate, the difference between this embodiment and example 1 is that the average particle size of the aluminum oxide is 50-60 nm.

[0064] Example 6

[0065] A processing technology of a sapphire substrate, the difference between this embodiment and example 1 is that the average particle size of the silicon nitride is 5-10 nm.

[0066] Example 7

[0067] A processing method of a sapphire substrate, different from the embodiment 1 is that the penetrant is obtained by mixing sodium polyacrylate and sodium phosphate according to a weight ratio of 1:3.

[0068] Embodiment 8

[0069] A processing method of a sapphire substrate, different from the embodiment 1 is that the penetrant is obtained by mixing sodium polyacrylate and sodium phosphate according to a weight ratio of 1:5.

[0070] Embodiment 9

[0071] A processing method of a sapphire substrate, different from the embodiment 1 is that the suspending agent is composed of polyvinyl alcohol and polyvinylpyrrolidone according to a weight ratio of 1:2.

[0072] Embodiment 10

[0073] A processing method of a sapphire substrate, different from the embodiment 7 is that the suspending agent is composed of polyvinyl alcohol and polyvinylpyrrolidone according to a weight ratio of 1:3.

[0074] Comparative example

[0075] Comparative example 1

[0076] A processing method of a sapphire substrate, different from the embodiment 1 is that the step S2 is omitted.

[0077] Comparative example 2

[0078] A processing method of a sapphire substrate, different from the embodiment 1 is that the diamond powder is used instead of silicon nitride in the rough grinding liquid.

[0079] Comparative example 3

[0080] A processing method of a sapphire substrate, different from the embodiment 1 is that the diamond powder is used instead of tungsten carbide in the fine grinding liquid.

[0081] Comparative example 4

[0082] A processing method of a sapphire substrate, different from the embodiment 1 is that the diamond powder is used instead of silicon nitride in the polishing liquid.

[0083] Comparative example 5

[0084] A processing method of a sapphire substrate, different from the embodiment 1 is that the cleaning liquid is purchased from the market, purchased from Dongguan City Hill Metal Material Co., Ltd., and the model is HR-332.

[0085] Detection method / test method

[0086] The number of cracks and scratches: 50 sapphire substrates were prepared according to the preparation processes of Examples 1-10 and Comparative Examples 1-7, respectively, and the sapphire substrate pieces were observed using an atomic force microscope at 500 times, and the total number of cracks and scratches was counted.

[0087] Surface roughness: the sapphire substrates were measured using a roughness tester.

[0088] Contaminant residue: the sapphire substrate wafer was scanned using an electron microscope to observe the surface contaminant residue. The experimental data are shown in Table 2:

[0089] Table 2 Experimental data of Examples 1-10 and Comparative Examples 1-5

[0090]

[0091]

[0092] Comparing Example 1 with Comparative Example 1, the total number of cracks and scratches in Comparative Example 1 was 5, and the surface roughness was greater than that of Example 1, indicating that coating the sapphire substrate with silicone oil is beneficial to reducing the number of cracks and scratches during sapphire substrate processing, and improving the flatness of the sapphire substrate surface.

[0093] Comparing Example 1 with Comparative Examples 2-4, the total number of cracks and scratches in Comparative Examples 2-4 was 8, 9 and 11, respectively; and the surface roughness was greater than that of Example 1, indicating that by reasonably matching the solid particles during rough grinding, fine grinding and polishing, the number of cracks and scratches during sapphire substrate processing can be reduced, and the flatness of the sapphire substrate surface can be improved.

[0094] Comparing Example 1 with Comparative Example 5, the surface roughness of Comparative Example 5 was greater than that of Example 1, and the number of particles greater than 0.5 μm in Comparative Example 5 was 11, indicating that using the cleaning solution in the present application is beneficial to removing residual contaminants in the process.

[0095] Comparing Example 1 with Examples 4-6, the total number of cracks and scratches in Examples 4-6 was 3, 4 and 3, respectively, and the surface roughness was greater than that of Example 1, indicating that optimizing the average particle size of the solid particles is beneficial to reducing the number of cracks and scratches during sapphire substrate processing, and improving the flatness of the sapphire substrate surface.

[0096] Comparing Example 1 with Examples 7-8, the surface roughness of Examples 7-8 was less than that of Example 1, indicating that by using sodium polyacrylate and sodium phosphate according to a specific ratio, the flatness of the sapphire substrate surface can be improved.

[0097] Compared with Example 1 and Example 9, the surface roughness of Example 9 is less than that of Example 1;

[0098] Compared with Example 7 and Example 10, the surface roughness of Example 7 is less than that of Example 10;

[0099] From the experimental data of Example 1, 9 and Example 7, 10, it can be seen that by using polyvinyl alcohol and polyvinyl pyrrolidone in a specific ratio, the flatness of the surface of the sapphire substrate can be improved.

[0100] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A process for processing a sapphire substrate, characterized by, The preparation steps include: S1, cutting sapphire to obtain a sapphire sheet; S2, coating the surface of the sapphire sheet with a layer of silicone oil to obtain a pretreated sapphire sheet; S3, using a silk polishing pad to coarsely polish the pretreated sapphire sheet to obtain a coarsely polished sapphire sheet, wherein a coarsely polishing liquid is used in the process, and the coarsely polishing liquid is composed of silicon nitride, silicon dioxide, a dispersing agent, a surfactant, a penetrating agent, and water in a weight ratio of (5-9):(3-5):(2-3):(1-2):(0.5-1):13; S4, using a non-woven polishing pad to finely polish the coarsely polished sapphire sheet to obtain a finely polished sapphire sheet, wherein a fine polishing liquid is used in the process, and the fine polishing liquid is composed of aluminum oxide, tungsten carbide, sodium hydroxyethyl cellulose, phosphoric acid carboxylic acid, a defoaming agent, stearic acid, a suspending agent, and water in a weight ratio of (4-6):(3-5):(2-3):(1-2):(0.5-0.8):(2-3):(2-4):15; S5, using a polyurethane polishing pad to chemically mechanically polish the finely polished sapphire sheet to obtain a polished sapphire sheet, wherein a polishing liquid is used in the process, and the polishing liquid is composed of silicon nitride, aluminum oxide, tris-hydroxymethyl aminomethane, diethylenetriamine pentaacetic acid, polyol fatty acid ester, ricinoleic acid, hydroxyethyl cellulose, and water in a weight ratio of (3-6):(4-6):(1-2):(0.5-1):(2-3):(4-6):(1-2):15; S6, immersing the polished sapphire sheet in a cleaning liquid, taking it out, washing it with purified water, and drying it to obtain a sapphire substrate, wherein the cleaning liquid is composed of an oxidizing agent, neopentyl glycol, isopropyl alcohol amine, sodium dodecyl sulfonate, and purified water in a weight ratio of (0.5-1):(3-5):(2-4):(1-3):

20.

2. The process for processing a sapphire substrate according to claim 1, wherein: The average particle size of the silicon nitride is 50-100 nm, and the average particle size of the silicon dioxide is 20-50 nm.

3. The process for processing a sapphire substrate according to claim 2, wherein: The average particle size of the aluminum oxide is 20-50 nm, and the average particle size of the tungsten carbide is 50-90 nm.

4. The process for processing a sapphire substrate according to claim 1, wherein: The average particle size of the silicon nitride is 5-10 nm, and the average particle size of the aluminum oxide is 10-20 nm.

5. The process for processing a sapphire substrate according to claim 4, wherein: The penetrating agent is obtained by mixing sodium polyacrylate and sodium phosphate in a weight ratio of 1:(3-5).

6. The process for processing a sapphire substrate according to claim 4, wherein: The suspending agent is composed of polyvinyl alcohol and polyvinylpyrrolidone in a weight ratio of 1:(2-3).

7. The process for processing a sapphire substrate according to claim 1, wherein: A cutting liquid is used in the cutting process of step S1, and the cutting liquid is composed of lauryl polyethylene glycol ester, sodium isobenzene propyl sulfonate, polyoxyethylene, methyl glycine diacetate trisodium, and water in a weight ratio of (2-3):(1-2):(2-4):(0.5-1):

8.

8. The process for processing a sapphire substrate according to claim 1, wherein: The rough grinding load in step S2 is 15-25 g / cm 2 The polishing liquid flow rate is 50-100 ml / min, and the polishing time is 25-30 min.

9. The process for processing a sapphire substrate according to claim 1, wherein: In step S3, the fine polishing load is 25-60 g / cm2, the polishing speed is 80-120 rpm, the polishing liquid flow rate is 150-250 ml / min, and the polishing time is 10-30 min.

10. The process for processing a sapphire substrate according to claim 1, wherein: The polishing load in step S4 is 100-150 g / cm 2 The polishing rotation speed is 100-200 rpm, the polishing liquid flow rate is 100-200 ml / min, and the polishing time is 120-240 min.

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