Polishing solution for aluminum nitride ceramic substrate and preparation method thereof

Abstract

The invention relates to the technical field of grinding and polishing, in particular to a polishing solution for an aluminum nitride ceramic substrate and a preparation method of the polishing solution. The polishing solution for the aluminum nitride ceramic substrate is mainly prepared from the following components in parts by mass: 0.5 to 10 parts of mixed grinding material, 0.5 to 10 parts of dispersing agent, 0.1 to 6 parts of anti-crystallizing agent, 0.05 to 5 parts of pH (Potential of Hydrogen) regulator and 80 to 100 parts of deionized water, and the pH value of the polishing solution is 7.1-8.5. The polishing solution disclosed by the invention can be used for effectively polishing the aluminum nitride ceramic substrate, so that the polishing rate is increased, the surface roughness is obviously reduced, and secondary scratches in the polishing process of the aluminum nitride ceramic substrate are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of grinding and polishing, and in particular to a polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof. Background Art

[0002] In the field of ceramic material processing technology, aluminum nitride ceramic substrates are widely used in electronics, aerospace, military and other fields due to their high hardness, high thermal conductivity, low thermal expansion coefficient and good electrical insulation performance. Aluminum nitride ceramic substrates need to undergo a wafer polishing process before application, and the surface damage of the wafer after grinding needs to be removed to achieve the surface roughness and polishing efficiency required by the aluminum nitride ceramic substrate. In general, the surface roughness Ra value of aluminum nitride ceramic substrates should be less than 30nm, and the material removal rate should be in the range of 0.5μm to 2μm per hour.

[0003] Chemical mechanical polishing is currently the most important flattening ultra-precision processing method for aluminum nitride ceramics. However, in this process, due to the high hardness and high brittleness of aluminum nitride ceramics, there are problems such as low removal rate and relatively slow material removal speed during the processing. In addition, the polishing liquid is prone to crystallization due to heat during the polishing process, which will cause secondary scratches or unevenness on the polished surface, making it difficult to achieve the surface roughness and polishing efficiency required for polishing aluminum nitride ceramic substrates. Therefore, how to prepare an efficient and stable polishing liquid to meet the surface roughness and polishing efficiency requirements of aluminum nitride ceramic substrates is an important problem facing current technology.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The present invention provides a polishing liquid for an aluminum nitride ceramic substrate, wherein the polishing liquid is mainly composed of the following components in parts by mass: 0.5 to 10 parts of mixed abrasive, 0.5 to 10 parts of dispersant, 0.1 to 6 parts of anti-crystallization agent, 0.05 to 5 parts of pH regulator, and 80 to 100 parts of deionized water; The pH of the polishing liquid adjusted by the pH adjusting agent is 7.1~8.5.

[0006] Preferably, the mixed abrasive comprises aluminum oxide abrasive, nano-diamond abrasive and nano-cerium oxide abrasive.

[0007] More preferably, the mass ratio of the aluminum oxide abrasive, the nano-diamond abrasive and the nano-cerium oxide abrasive in the mixed abrasive is 9:1:2 to 20:1:2.

[0008] Further preferably, in the mixed abrasive, the particle size of the aluminum oxide abrasive is 200nm-500nm, the particle size of the nano-diamond abrasive is 80nm-100nm, and the particle size of the nano-cerium oxide abrasive is 30nm-60nm.

[0009] Preferably, the dispersant is a mixture of polyethylene glycol and ammonium polyacrylate.

[0010] More preferably, the mass ratio of polyethylene glycol to ammonium polyacrylate in the dispersant is 1:4 to 4:1.

[0011] Preferably, the anti-crystallization agent is a mixture of ethylenediaminetetraacetic acid (EDTA) and polyvinylpyrrolidone (PVP).

[0012] More preferably, the mass ratio of ethylenediaminetetraacetic acid (EDTA) to polyvinylpyrrolidone (PVP) in the anticrystallization agent is 1:3 to 3:1.

[0013] Preferably, the pH adjuster includes one or more of sodium hydroxide, potassium hydroxide, ammonia water, and sodium carbonate.

[0014] The present invention also provides a method for preparing a polishing liquid for an aluminum nitride ceramic substrate, the preparation method comprising the following steps: (1) Weigh a certain amount of abrasive according to the proportion and mix them evenly; (2) Weigh a certain amount of dispersant according to proportion, add a certain amount of deionized water into a container, add the dispersant under stirring, and obtain a dispersant mixed solution; (3) Weigh a certain amount of anti-crystallization agent according to the proportion; (4) adding the mixed abrasive in (1) and the anti-crystallization agent in (3) to the dispersant mixture prepared in (2) in sequence under stirring, and subjecting to ultrasonic treatment for 20 to 30 minutes; (5) Weigh a certain amount of pH adjuster and dissolve it in a certain amount of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed solution prepared in (4) under stirring to adjust the pH of the mixed solution to 7.1-8.5, thereby obtaining a polishing liquid for an aluminum nitride ceramic substrate.

[0015] The polishing liquid for the aluminum nitride ceramic substrate provided by the present invention can effectively perform polishing treatment on the aluminum nitride ceramic substrate, improve the polishing rate, significantly reduce the surface roughness, and reduce secondary scratches during the polishing process.

[0016] In the selection of polishing liquid abrasives, the present invention optimizes the ratio and performance of the abrasives, adopts a mixture of aluminum oxide abrasives, nano diamond abrasives and nano cerium oxide abrasives as the main abrasives, and adjusts the mass ratio of the three abrasives and controls the particle size of the three abrasives, thereby improving the polishing efficiency of the aluminum nitride ceramic substrate and reducing the surface roughness. The mixture of the three abrasives can give full play to the advantages of the three abrasives, produce a synergistic effect, and has the beneficial effects of improving the polishing efficiency, improving the surface quality of the polished workpiece and extending the service life of the polishing liquid. The hardness and cutting ability of the aluminum oxide abrasive, the nano diamond abrasive and the nano cerium oxide abrasive are different, and the mixed use can give play to their respective advantages at different polishing stages. In the early stage of polishing, the high hardness of the aluminum oxide abrasive can quickly remove the rough parts and high points on the surface of the aluminum nitride ceramic substrate, thereby improving the polishing efficiency. As the polishing proceeds, the extremely high hardness and nano size effect of the nano diamond abrasive can finely polish the substrate surface. Finally, the chemical activity and good dispersibility of the cerium oxide abrasive can further remove the fine flaws on the surface, improve the surface finish, and obtain extremely high surface accuracy and quality. Different abrasives have different wear mechanisms and speeds. Mixing them can complement each other and reduce the excessive wear of a single abrasive. The high hardness of aluminum oxide abrasives may cause them to wear faster during polishing, while nano diamond abrasives and nano cerium oxide abrasives wear relatively slowly. Mixing them can keep the abrasive particles in the polishing liquid at a relatively stable ratio and extend the service life of the polishing liquid.

[0017] In the selection of the dispersant used in the polishing liquid, the present invention adopts a mixture of polyethylene glycol and ammonium polyacrylate as a dispersant, and preferably, the mass ratio of the two dispersants is 1:4~4:1. Mixing polyethylene glycol and ammonium polyacrylate as a dispersant can play a synergistic role. First, the mixture of polyethylene glycol and ammonium polyacrylate as a dispersant can play an electrostatic stabilizing role. Ammonium polyacrylate is a negatively charged polymer that can produce a large number of carboxylate ions in the solution through ionization. These ions can be adsorbed on the surface of aluminum nitride ceramic particles, making the particles negatively charged. Since like charges repel each other, electrostatic repulsion is generated between the particles to prevent the particles from agglomerating. Polyethylene glycol can also form hydrogen bonds with water molecules through its ether oxygen atoms in the solution, thereby forming a hydration film on the surface of the particles. This hydration film can increase the charge density on the surface of the particles, further enhance the electrostatic repulsion, and improve the dispersion stability of the particles. Secondly, the mixture of polyethylene glycol and ammonium polyacrylate as a dispersant can play a steric hindrance role. Polyethylene glycol is a high molecular polymer, and its molecular chain can stretch in the solution and adsorb on the surface of aluminum nitride ceramic particles to form a steric hindrance layer. This steric hindrance layer can prevent the particles from approaching and agglomerating each other, thereby improving the dispersion stability of the particles. The molecular chain of ammonium polyacrylate can also form a certain steric hindrance effect on the surface of the particles. At the same time, since ammonium polyacrylate carries a negative charge, it can form an electrostatic attraction with the ether oxygen atoms on the polyethylene glycol molecular chain, thereby enhancing the adsorption stability of the two dispersants on the particle surface and further improving the steric hindrance effect. Thirdly, the mixture of polyethylene glycol and ammonium polyacrylate as a dispersant can play a wetting role. Both polyethylene glycol and ammonium polyacrylate have good water solubility, which can reduce the surface tension of the solution and improve the wetting ability of aluminum nitride ceramic particles. Good wetting can make the dispersant more easily adsorbed on the particle surface, thereby improving the dispersion stability of the particles. In addition, polyethylene glycol and ammonium polyacrylate can also form hydrogen bonds or other chemical bonding with functional groups such as hydroxyl groups on the surface of aluminum nitride ceramic particles, further enhancing the adsorption stability of the dispersant on the particle surface. In summary, the mixture of polyethylene glycol and ammonium polyacrylate as a dispersant can synergistically improve the dispersion stability of aluminum nitride ceramic particles through multiple mechanisms such as electrostatic stabilization, steric hindrance and wetting, thereby achieving a better dispersion effect during the polishing process of the aluminum nitride ceramic substrate, improving the polishing efficiency and surface quality.

[0018] In the selection of the anti-crystallization agent used in the polishing liquid, the present invention selects a mixture of ethylenediaminetetraacetic acid (EDTA) and polyvinyl pyrrolidone (PVP), preferably, the mass ratio of ethylenediaminetetraacetic acid (EDTA) and polyvinyl pyrrolidone (PVP) is 1:3~3:1. The mixture of ethylenediaminetetraacetic acid (EDTA) and polyvinyl pyrrolidone (PVP) has a synergistic effect as an anti-crystallization agent, and its synergistic effect is specifically manifested as follows: first, it has a synergistic complexing effect. Ethylenediaminetetraacetic acid is a strong complexing agent, which can form a stable complex with metal ions. In the polishing process of aluminum nitride ceramic substrates, the metal ions that may exist will promote the formation of crystals, and these metal ions can be complexed to reduce their concentration, thereby inhibiting the occurrence of crystallization in the polishing liquid. Polyvinyl pyrrolidone molecules contain coordination atoms such as nitrogen and oxygen, which can have a certain degree of complexation with metal ions. Although the complexing ability of polyvinyl pyrrolidone is relatively weak, when used in combination with ethylenediaminetetraacetic acid, it can enhance the complexing effect on metal ions and improve the anti-crystallization performance. Secondly, it has a synergistic steric hindrance effect. Polyvinylpyrrolidone (PVP) is a high molecular polymer whose molecular chain can stretch in solution and form a steric hindrance layer. This steric hindrance layer can prevent the growth and aggregation of crystals, thereby playing an anti-crystallization role. The complex formed by ethylenediaminetetraacetic acid (EDTA) and metal ions also has a certain steric hindrance effect, which can further enhance the inhibitory effect on crystal growth. At the same time, when ethylenediaminetetraacetic acid (EDTA) and polyvinylpyrrolidone (PVP) work together, a more complex steric hindrance structure can be formed on the surface of the crystal, effectively preventing the formation and growth of crystals. Thirdly, it has a synergistic adsorption effect. PVP can be adsorbed on the surface of the crystal through hydrogen bonds, van der Waals forces and other forces, changing the surface properties of the crystal, reducing the surface energy of the crystal, and thus inhibiting the growth of the crystal. The complex formed by EDTA and metal ions can also be adsorbed on the surface of the crystal, and work together with PVP to enhance the inhibitory effect on crystal growth. In summary, the mixture of EDTA and PVP has a synergistic effect as an anti-crystallization agent, which can jointly inhibit the formation of crystals through multiple mechanisms such as complexation, steric hindrance and adsorption, and improve the stability and polishing effect of the polishing solution for aluminum nitride ceramic substrates.

[0019] The present invention accurately controls the pH value of the polishing liquid to 7.1-8.5, so that the polishing liquid is weakly alkaline. For the aluminum nitride ceramic substrate polishing liquid, the weakly alkaline environment in this pH range can promote chemical reactions in the polishing process, improve material removal efficiency and improve the surface quality of the substrate to a certain extent. First, the weakly alkaline environment is conducive to specific chemical reactions on the surface of the aluminum nitride ceramic substrate. Under weakly alkaline conditions, the oxides or impurities on the surface of aluminum nitride are more likely to react with the components in the polishing liquid and be removed. Secondly, the weakly alkaline environment helps to adjust the material removal method during the polishing process. Under weakly alkaline conditions, the interaction between the abrasive particles and the substrate surface will change, making the material removal more uniform and smooth. The generation of scratches and surface defects can be reduced, and the surface quality of the substrate can be improved. Thirdly, the weakly alkaline pH value can enhance the stability of each component in the polishing liquid.

[0020] In addition, the weak alkaline environment also has a beneficial effect on the performance of aluminum nitride substrates. The surface of aluminum nitride ceramic substrates polished under weak alkaline conditions is smoother and flatter, and the roughness is reduced. Compared with the acidic environment, the weak alkaline environment is less corrosive to aluminum nitride ceramic substrates. It can reduce the risk of corrosion of the substrate during the polishing process and protect the structure and performance of the substrate. At the same time, it also reduces the corrosion of polishing equipment and extends the service life of the equipment.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. High polishing efficiency: The present invention adopts a mixture of aluminum oxide abrasive, nano-diamond abrasive and nano-cerium oxide abrasive in a specific ratio, which can effectively remove the defects on the surface of aluminum nitride ceramic substrate and improve the polishing efficiency. At the same time, by optimizing the ratio and performance of dispersant, anti-crystallization agent and pH regulator, the polishing effect can be further improved, the surface roughness can be reduced, and the secondary damage to the substrate can be reduced.

[0022] 2. Stable polishing effect: In the polishing liquid of the present invention, the amount of abrasive materials and various additives added can be precisely controlled to ensure the stability and repeatability of the polishing effect. This can not only improve production efficiency, but also ensure the quality consistency of the product.

[0023] 3. Wide application scope: Since the polishing liquid of the present invention has the characteristics of high efficiency, stability and environmental protection, it can be widely used in the fields of electronics, aerospace, military and the like, meeting the requirements of different industries for the surface quality of aluminum nitride ceramic substrates.

[0024] In general, compared with the prior art, the present invention has higher polishing efficiency, more stable polishing effect, wider application range, low cost and high benefit, and is an ideal polishing liquid for aluminum nitride ceramic substrates. DETAILED DESCRIPTION

[0025] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased on the market.

[0026] Embodiment 1: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) 0.5 parts of mixed abrasives were selected, and 0.375 parts of aluminum oxide abrasive with a particle size of 300 nm, 0.042 parts of nano-diamond abrasive with a particle size of 80 nm, and 0.083 parts of nano-cerium oxide abrasive with a particle size of 30 nm were weighed in a mass ratio of 9:1:2, and then mixed evenly; (2) Select 0.5 parts of dispersant, and weigh 0.1 parts of dispersant polyethylene glycol and 0.4 parts of ammonium polyacrylate in a mass ratio of 1:4. Add 75 parts of deionized water into a container, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 0.1 part of anticrystallization agent. According to the mass ratio of 1:3, weigh 0.025 parts of ethylenediaminetetraacetic acid (EDTA) and 0.075 parts of polyvinylpyrrolidone (PVP), respectively, and mix them to form an anticrystallization agent mixture for use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting the mixture to ultrasonic treatment for 20 minutes; (5) Weigh 0.05 parts of sodium hydroxide and dissolve it in 5 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.1 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0027] Embodiment 2: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) Select 1 part of the mixed abrasive, weigh 0.769 parts of aluminum oxide abrasive with a particle size of 400 nm, 0.077 parts of nano-diamond abrasive with a particle size of 80 nm, and 0.154 parts of nano-cerium oxide abrasive with a particle size of 40 nm, in a mass ratio of 10:1:2, and mix them evenly; (2) Select 2 parts of dispersant, weigh 0.5 parts of dispersant polyethylene glycol and 1.5 parts of ammonium polyacrylate in a mass ratio of 1:3. Add 80 parts of deionized water into a container, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 0.6 parts of anticrystallization agent, weigh 0.2 parts of ethylenediaminetetraacetic acid (EDTA) and 0.4 parts of polyvinylpyrrolidone (PVP) in a mass ratio of 1:2, and mix them to form an anticrystallization agent mixture for later use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting the mixture to ultrasonic treatment for 25 minutes; (5) Weigh 0.1 parts of sodium hydroxide and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.2 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0028] Embodiment 3: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) Select 3 parts of mixed abrasives, weigh 2.2 parts of aluminum oxide abrasive with a particle size of 400 nm, 0.2 parts of nano diamond abrasive with a particle size of 80 nm, and 0.6 parts of nano cerium oxide abrasive with a particle size of 40 nm, in a mass ratio of 11:1:2, and mix them evenly; (2) Select 2 parts of dispersant, weigh 0.67 parts of polyethylene glycol and 1.33 parts of ammonium polyacrylate in a mass ratio of 1:2. Add 75 parts of deionized water into a container, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 1 part of anticrystallization agent. According to the mass ratio of 1:1, weigh 0.5 parts of ethylenediaminetetraacetic acid (EDTA) and 0.5 parts of polyvinylpyrrolidone (PVP), respectively, and mix them to form an anticrystallization agent mixture for use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 30 minutes; (5) Weigh 0.1 parts of sodium hydroxide and 0.1 parts of sodium hydroxide, and dissolve them in 20 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.3 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0029] Embodiment 4: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) Select 4 parts of mixed abrasives, weigh 3 parts of aluminum oxide abrasive with a particle size of 400 nm, 0.25 parts of nano-diamond abrasive with a particle size of 80 nm, and 0.75 parts of nano-cerium oxide abrasive with a particle size of 40 nm, in a mass ratio of 12:1:2, and mix them evenly; (2) Select 4 parts of dispersant, weigh 2 parts of dispersant polyethylene glycol and 2 parts of ammonium polyacrylate in a mass ratio of 1:1. Add 80 parts of deionized water into a container, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 3 parts of anticrystallization agent. According to the mass ratio of 1:1, weigh 1.5 parts of ethylenediaminetetraacetic acid (EDTA) and 1.5 parts of polyvinylpyrrolidone (PVP), respectively, and mix them to form an anticrystallization agent mixture for use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 30 minutes; (5) Weigh 5 parts of aqueous ammonia and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.4 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0030] Embodiment 5: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) Select 6 parts of mixed abrasives, and weigh 4.875 parts of aluminum oxide abrasive with a particle size of 400 nm, 0.375 parts of nano-diamond abrasive with a particle size of 80 nm, and 0.75 parts of nano-cerium oxide abrasive with a particle size of 40 nm, in a mass ratio of 13:1:2, and then mix them evenly; (2) Select 4 parts of dispersant, weigh 2.64 parts of dispersant polyethylene glycol and 1.33 parts of ammonium polyacrylate in a mass ratio of 2:1. Add 85 parts of deionized water into a container, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 3 parts of anticrystallization agent. Weigh 2 parts of ethylenediaminetetraacetic acid (EDTA) and 1 part of polyvinylpyrrolidone (PVP) in a mass ratio of 2:1, respectively, and mix them to form an anticrystallization agent mixture for later use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 30 minutes; (5) Weigh 4 parts of ammonia water and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.5 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0031] Embodiment 6: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) Select 7 parts of mixed abrasives, and weigh 5.44 parts of aluminum oxide abrasive with a particle size of 450 nm, 0.39 parts of nano-diamond abrasive with a particle size of 90 nm, and 1.17 parts of nano-cerium oxide abrasive with a particle size of 50 nm, in a mass ratio of 14:1:2, and mix them evenly; (2) Select 5 parts of dispersant, weigh 2.5 parts of dispersant polyethylene glycol and 2.5 parts of ammonium polyacrylate in a mass ratio of 1:1. Add 89 parts of deionized water into a container, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 4 parts of anticrystallization agent, weigh 3 parts of ethylenediaminetetraacetic acid (EDTA) and 1 part of polyvinylpyrrolidone (PVP) in a mass ratio of 3:1, mix them to form an anticrystallization agent mixture for later use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and performing ultrasonic treatment for 19 minutes; (5) Weigh 3 parts of sodium carbonate and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.5 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0032] Embodiment 7: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) 8 parts of mixed abrasives were selected, and according to the mass ratio of 15:1:2, 6 parts of aluminum oxide abrasive with a particle size of 500 nm, 0.4 parts of nano diamond abrasive with a particle size of 90 nm, and 1.6 parts of nano cerium oxide abrasive with a particle size of 60 nm were weighed respectively, and then mixed evenly; (2) Select 6 parts of dispersant, weigh 4 parts of dispersant polyethylene glycol and 2 parts of ammonium polyacrylate in a mass ratio of 2:1. Add 90 parts of deionized water into a container, add the above dispersants in sequence under stirring, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 5 parts of anticrystallization agent. According to the mass ratio of 3:1, weigh 3.75 parts of ethylenediaminetetraacetic acid (EDTA) and 1.25 parts of polyvinylpyrrolidone (PVP), respectively, and mix them to form an anticrystallization agent mixture for use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 30 minutes; (5) Weigh 2 parts of sodium carbonate and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 7.6 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0033] Embodiment 8: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) 9 parts of mixed abrasives were selected, and 6.65 parts of aluminum oxide abrasive with a particle size of 500 nm, 0.39 parts of nano-diamond abrasive with a particle size of 100 nm, and 1.96 parts of nano-cerium oxide abrasive with a particle size of 60 nm were weighed respectively according to a mass ratio of 17:1:2, and then mixed evenly; (2) Select 6 parts of dispersant, weigh 4.5 parts of dispersant polyethylene glycol and 1.5 parts of ammonium polyacrylate in a mass ratio of 3:1. Add 90 parts of deionized water into a container, add the above dispersants in sequence under stirring, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 5 parts of anticrystallization agent. According to the mass ratio of 3:1, weigh 3.75 parts of ethylenediaminetetraacetic acid (EDTA) and 1.25 parts of polyvinylpyrrolidone (PVP), respectively, and mix them to form an anticrystallization agent mixture for use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 30 minutes; (5) Weigh 1 part of sodium carbonate and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 8, thereby obtaining a polishing liquid for an aluminum nitride ceramic substrate.

[0034] Embodiment 9: This embodiment provides a high-efficiency polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) 10 parts of mixed abrasives were selected, and 7.69 parts of aluminum oxide abrasive with a particle size of 500 nm, 0.38 parts of nano-diamond abrasive with a particle size of 100 nm, and 1.92 parts of nano-cerium oxide abrasive with a particle size of 60 nm were weighed respectively according to a mass ratio of 20:1:2, and then mixed evenly; (2) Select 10 parts of dispersant, weigh 8.0 parts of dispersant polyethylene glycol and 2.0 parts of ammonium polyacrylate in a mass ratio of 4:1. Add 90 parts of deionized water into a container, add the above dispersants in sequence under stirring, and add the above dispersants in sequence under stirring to obtain a dispersant mixed solution; (3) Select 5 parts of anticrystallization agent, weigh ethylenediaminetetraacetic acid (EDTA) and polyvinylpyrrolidone (PVP) in a mass ratio of 3:1, and mix them to form an anticrystallization agent mixture for later use; (4) adding the abrasive mixture in (1) and the anti-crystallization agent mixture in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 30 minutes; (5) Weigh 2 parts of sodium carbonate and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 8.5 to obtain a polishing liquid for an aluminum nitride ceramic substrate.

[0035] Comparative Example 1: This comparative example provides a polishing liquid for an aluminum nitride ceramic substrate and a preparation method thereof, and the specific steps are as follows: (1) Weigh 15 parts of aluminum oxide abrasive with a particle size of 150 nm; (2) Weigh 10 parts of polyethylene glycol as a dispersant; add 90 parts of deionized water into a container, and add the above dispersant under stirring to obtain a dispersion; (3) Weigh 7 parts of anti-crystallization agent ethylenediaminetetraacetic acid (EDTA); (4) adding the abrasive in (1) and the anti-crystallization agent mixture in (3) to the dispersion prepared in (2) under stirring, and subjecting to ultrasonic treatment for 10 minutes; (5) Weigh 5 parts of sodium hydroxide and dissolve it in 10 parts of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring until the pH value reaches 10, thereby obtaining a polishing liquid for an aluminum nitride ceramic substrate. Experimental example

[0036] Polishing comparison experiments were carried out using the polishing solutions of Examples 1 to 9 and Comparative Example 1, and the specific experimental results are shown in Table 1.

[0037] Table 1 Polishing effect Examples and Comparative Examples Polishing rate Surface Ra (nm) Example 1 0.6μm / h 15 Example 2 0.8μm / h 16 Example 3 0.9μm / h 14 Example 4 1.0μm / h 13 Example 5 1.2μm / h 14 Example 6 1.3μm / h 15 Example 7 1.4μm / h 18 Example 8 1.5μm / h 19 Example 9 1.7μm / h 20 Comparative Example 1 0.4μm / h 40 From the polishing effect, it can be seen that in Examples 1 to 9, the aluminum nitride ceramic substrate is polished according to the technical solution provided by the present invention, and the surface roughness Ra value is between 15nm and 20nm; the material removal rate is in the range of 0.6μm to 1.7μm per hour. The surface roughness and polishing efficiency required for the aluminum nitride ceramic substrate can be achieved. However, the technical solution used in the comparative example exceeds the technical scope provided by the present invention, and in the results of polishing the aluminum nitride ceramic substrate, the polishing efficiency and surface roughness do not meet the requirements.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polishing liquid for an aluminum nitride ceramic substrate, characterized in that: It is mainly composed of the following components by mass: 0.5 to 10 parts of mixed abrasive, 0.5 to 10 parts of dispersant, 0.1 to 6 parts of anti-crystallization agent, 0.05 to 5 parts of pH regulator, and 80 to 100 parts of deionized water; The pH of the polishing liquid is adjusted to 7.1-8.5 by using a pH adjuster.

2. The polishing liquid for aluminum nitride ceramic substrate according to claim 1, characterized in that: The mixed abrasive comprises aluminum oxide abrasive, nano diamond abrasive and nano cerium oxide abrasive.

3. The polishing liquid for aluminum nitride ceramic substrate according to claim 2, characterized in that: The mass ratio of the aluminum oxide abrasive, the nano-diamond abrasive and the nano-cerium oxide abrasive in the mixed abrasive is 9:1:2-20:1:

2.

4. The polishing liquid for aluminum nitride ceramic substrate according to claim 2, characterized in that: In the mixed abrasive, the particle size of the aluminum oxide abrasive is 200nm-500nm, the particle size of the nano diamond abrasive is 80nm-100nm, and the particle size of the nano cerium oxide abrasive is 30nm-60nm.

5. The polishing liquid for aluminum nitride ceramic substrate according to claim 1, characterized in that: The dispersant is a mixture of polyethylene glycol and ammonium polyacrylate.

6. The polishing liquid for aluminum nitride ceramic substrate according to claim 5, characterized in that: The mass ratio of the dispersant polyethylene glycol to ammonium polyacrylate is 1:4 to 4:

1.

7. The polishing liquid for aluminum nitride ceramic substrate according to claim 1, characterized in that: The anti-crystallization agent is a mixture of ethylenediaminetetraacetic acid (EDTA) and polyvinylpyrrolidone (PVP).

8. The polishing liquid for aluminum nitride ceramic substrate according to claim 7, characterized in that: The mass ratio of ethylenediaminetetraacetic acid (EDTA) to polyvinylpyrrolidone (PVP) in the anti-crystallization agent is 1:3-3:

1.

9. The polishing liquid for aluminum nitride ceramic substrate according to claim 1, characterized in that: The pH regulator includes one or more of sodium hydroxide, potassium hydroxide, ammonia water, and sodium carbonate.

10. The method for preparing a polishing liquid for an aluminum nitride ceramic substrate according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Weigh a certain amount of abrasive according to the proportion and mix them evenly; (2) Weigh a certain amount of dispersant according to a certain ratio, add a certain amount of deionized water into a container, and add the dispersant under stirring to obtain a dispersant mixed solution; (3) Weigh a certain amount of anti-crystallization agent according to proportion; (4) adding the mixed abrasive in (1) and the anti-crystallization agent in (3) to the dispersant mixture prepared in (2) under stirring, and subjecting to ultrasonic treatment for 20 min to 30 min; (5) Weighing a certain amount of pH adjuster, dissolving it in a certain amount of deionized water to obtain a pH adjusting solution; (6) The pH adjusting liquid is added to the mixed liquid prepared in (4) under stirring to adjust the pH of the mixed liquid to 7.1-8.5, thereby obtaining a polishing liquid for an aluminum nitride ceramic substrate.