Preparation method of nano cerium oxide polishing solution

Abstract

The invention relates to the technical field of preparation of polishing solutions, in particular to a preparation method of a nano cerium oxide polishing solution, which comprises the following steps: material preparation and screening, material grinding and screening, quantitative feeding and material mixing. Through ingenious connection of a plurality of components, cerium oxide particle materials can be fully ground, it is ensured that material particles are nanoscale, the cerium oxide particles can become high-quality grinding materials, the quality of a final grinding agent is improved, accurate burdening and uniform mixing of multiple materials are ensured, and through addition of the multiple materials, the grinding efficiency is improved. And the quality of the final polishing solution can be improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of polishing liquid preparation, in particular to a preparation method of a nano cerium oxide polishing liquid. BACKGROUND

[0002] With the continuous development of the integration level of integrated circuits, a shallow trench isolation (STI) technology is widely applied in the field of integrated circuit manufacturing. The STI structure plays a role in device isolation in high-density transistors, and the STI technology has become a mainstream isolation technology in recent decades. As the only means for global or local planarization in integrated circuit manufacturing, chemical mechanical polishing (CMP) is an important step in the manufacturing process of the STI structure. In the manufacturing process of the STI structure, a trench is created on the Si substrate around the active device, and SiO2 medium is filled. When the SiO2 is filled, the SiO2 will also be deposited in the area of the wafer that is not needed, and the excess SiO2 needs to be removed by the CMP technology. At the same time, in order to prevent damage to the important epitaxial layer on the Si substrate in the CMP process, a Si3N4 stop layer needs to be grown under the SiO2 deposition layer. Therefore, it is crucial to reduce the removal rate of Si3N4 as much as possible under the premise of a relatively high SiO2 removal rate. The SiO2 sol polishing SiO2 medium only relies on mechanical action to remove the SiO2 medium, and the removal rate of the SiO2 medium is relatively low, resulting in a too low removal rate selection ratio of SiO2 and Si3N4.

[0003] At present, the research on the removal rate selection ratio of STI CMP mainly focuses on inhibiting the removal rate of Si3N4, and the selected additives basically have no effect on the removal rate of SiO2. However, with the gradual increase of the transistor density of integrated circuits and the continuous progress of the technology node, the STI CMP requires to minimize the problems such as serious trench oxide loss and dishing defects caused by too fast SiO2 removal rate. Therefore, the appropriate SiO2 removal rate under the condition of high removal rate selection ratio is a problem to be solved.

[0004] The cerium oxide polishing liquid disclosed in CN120230481A contains the following components in mass fraction: 0.1%-10% cerium oxide abrasive particles, 0.1-5% polishing inhibitor, 0.01-5% dispersant, 0.01-2% pH regulator, 50-500 ppm anionic surfactant and water. The cerium oxide polishing liquid can control and regulate the removal rate of the polishing liquid, reduce the trench oxide loss, slow down the SiO removal rate, selectively remove the silicon oxide film, and has a good application prospect.

[0005] The above technical solution can clearly indicate the proportion of each material, but how to fully mix and prepare, and how to ensure the accuracy of the proportion between materials, so improvement is needed. SUMMARY

[0006] The purpose of the present application is to solve the problems existing in the prior art and provide a preparation method of nano cerium oxide polishing liquid.

[0007] To achieve the above purpose, the present application adopts the following technical solution:

[0008] A preparation method of nano cerium oxide polishing liquid, comprising the following steps:

[0009] S1, material preparation and selection: the staff prepares cerium oxide particle material, polishing inhibitor, dispersing agent, anti-settling agent, stabilizer, PH regulator, anionic surfactant and deionized water according to the needs

[0010] S2, grinding and screening of materials: the staff puts the cerium oxide particle material into the nanoscale spherulitic device, and fully grinds the cerium oxide particle material through the components in the nanoscale spherulitic device to ensure that the cerium oxide particle material is ground into nanoscale cerium oxide particles;

[0011] S3, quantitative feeding: the ground nanoscale cerium oxide particles and the prepared polishing inhibitor, dispersing agent, anti-settling agent, PH regulator, anionic surfactant and deionized water materials are respectively stored in a plurality of storage tanks, a feeding assembly is installed on the storage tank, and an electronic metering valve assembly is installed on the discharge pipe of the storage tank, a feeding pipe is connected to the discharge pipe of the storage tank, and a mixing tank is provided through the plurality of feeding pipes.

[0012] S4, material mixing: a stirring and mixing assembly is installed on the mixing tank, the lower end of the stirring and mixing assembly is located in the mixing tank, an electric control valve is installed on the discharge pipe of the mixing tank, and the stirring and mixing assembly can fully stir and mix the materials in the mixing tank.

[0013] Compared with the prior art, the present application can fully grind the cerium oxide particle material through the ingenious connection between multiple components, ensure that the material particles are nanoscale, make it become high-quality abrasive, improve the quality of the final grinding agent, and ensure the accurate proportioning and uniform mixing of multiple materials, and the addition of multiple materials helps to improve the quality of the final polishing liquid.

[0014] Preferably, a plurality of screens are provided at equal intervals between the feeding port and the discharge port of the nanoscale spherulitic device, and the screen located on one side of the discharge port has a mesh size of 120-200 meshes.

[0015] Further, it is ensured that the cerium oxide particle material in the final polishing liquid is in nanoscale.

[0016] Preferably, the stirring and mixing assembly is a double-roller stirring assembly, and the double rollers in the stirring and mixing assembly are each provided with a spiral conveying rod, and the thread structures on the two spiral conveying rods are oppositely arranged.

[0017] Further, the oppositely arranged thread structures can fully enable the deionized water to flow in disorder to drive other materials to be fully mixed.

[0018] Preferably, the bottoms of the storage tank and the mixing tank are conically arranged.

[0019] Further, the conical bottom structure can facilitate the rapid flow of materials.

[0020] Preferably, the spherulitic medium in the nanoscale spherulitic device is a zirconium oxide bead, the diameter of the zirconium oxide bead is between 0.3 mm and 0.5 mm, and the diameter of the zirconium oxide bead in the nanoscale spherulitic device gradually decreases from the feeding port to the discharging port.

[0021] Further, it is ensured that the cerium oxide particle material in the final polishing liquid is in nanoscale.

[0022] Preferably, the stabilizer is any one of polyvinyl alcohol, polyethylene glycol, polydimethylsiloxane, polyethylene oxide, polypropylene oxide, carboxymethyl cellulose, sodium polyacrylate, or hydroxyethyl methyl cellulose.

[0023] Further, the stabilizer can modify the cerium oxide without introducing metal ions, reduce the influence of metal ions on the polishing performance of the formed polishing liquid, and improve other physical properties of the polishing liquid while ensuring that the polishing performance is not affected.

[0024] Preferably, the dispersant is any one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, or histidine.

[0025] Further, the nanoscale cerium oxide particles can be uniformly dispersed.

[0026] Preferably, the polishing inhibitor is polymethacrylic acid, the PH regulator is an inorganic base or an organic base, and the anionic surfactant is a carboxylate or a sulfonate.

[0027] Further, the quality of the final product can be improved.

[0028] Preferably, the anti-settling agent comprises flaky particles; the average size of the flaky particles in the length direction is 0.5-3 microns, and the average size of the flaky particles in the width direction is 0.5-3 microns.

[0029] Further, the nano cerium oxide particles can be prevented from being deposited, so that the nano cerium oxide polishing liquid can be conveniently and quickly used.

[0030] The present application has the following advantages:

[0031] 1. The nano cerium oxide particles can be fully crushed by the nano ball mill, so that the particles are in the nano state, and the filter screen is arranged in the nano ball mill to ensure the quality of the discharged material and improve the quality of the final polishing liquid.

[0032] 2. The quality of each material added can be accurately controlled by the electronic metering valve assembly, so that the proportion of each material during mixing is accurate, and the material can be mixed faster by the stirring and mixing assembly. The stirring and mixing assembly cooperates with the degranulation water to fully make the material move irregularly, so as to ensure the quality of the mixing and avoid the area where the stirring is not in place.

[0033] 3. The quality of the final polishing agent can be improved by adding the matching medicament. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 A step diagram of the preparation method of the nano cerium oxide polishing liquid is provided.

[0035] Figure 2 A flow structure schematic diagram of the preparation method of the nano cerium oxide polishing liquid is provided.

[0036] Figure 3 A structure diagram of the nano ball mill in the preparation method of the nano cerium oxide polishing liquid is provided.

[0037] Figure 4 A sectional view of the nano ball mill in the preparation method of the nano cerium oxide polishing liquid is provided.

[0038] Figure 5 A connection structure diagram of the storage tank and the mixing tank in the preparation method of the nano cerium oxide polishing liquid is provided.

[0039] In the figure: 1 nano ball mill, 2 material conveying assembly, 3 storage tank, 4 electronic metering valve assembly, 5 mixing tank, 6 stirring and mixing assembly, 7 electric control valve. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application.

[0041] Referring to Figures 1-5 A preparation method of a nano cerium oxide polishing solution, comprising the following steps:

[0042] S1, material preparation and screening: the staff prepares cerium oxide particle material, polishing inhibitor, dispersing agent, anti-settling agent, stabilizer, PH regulator, anionic surfactant and deionized water according to the needs, and fully ensures the quality of the materials;

[0043] S2, grinding and screening of the material: the staff puts the cerium oxide particle material into the nanometer spheroidizing device 1, and fully grinds the cerium oxide particle material through the components in the nanometer spheroidizing device 1 to ensure that the cerium oxide particle material is ground into nanometer cerium oxide particles; a plurality of screens are arranged at equal intervals from the feeding port to the discharging port in the nanometer spheroidizing device 1, and the screen located on the side of the discharging port has a mesh size of 120-200 meshes; the spheroidizing medium in the nanometer spheroidizing device 1 is zirconium oxide beads, the diameter of the zirconium oxide beads is 0.3-0.5 mm, and the diameter of the zirconium oxide beads in the nanometer spheroidizing device 1 decreases from the feeding port to the discharging port to ensure the quality of the crushing of the cerium oxide particle material;

[0044] S3, quantitative feeding: the ground nanometer cerium oxide particles and the prepared polishing inhibitor, dispersing agent, anti-settling agent, PH regulator, anionic surfactant and deionized water material are respectively stored in a plurality of storage tanks 3, a feeding assembly 2 is installed on the storage tank 3, and an electronic metering valve assembly 4 is installed on the discharge pipe of the storage tank 3, a feeding pipe is connected to the discharge pipe of the storage tank 3, and a mixing tank 5 is arranged to penetrate through the plurality of feeding pipes; the bottom of the storage tank 3 and the mixing tank 5 are conical.

[0045] S4, material mixing: a stirring and mixing assembly 6 is installed on the mixing tank 5, the stirring and mixing assembly 6 is a double-roller stirring assembly, the double rollers in the stirring and mixing assembly 6 are both spiral feeding rods, and the thread structures on the two spiral feeding rods are oppositely arranged; the lower end of the stirring and mixing assembly 6 is located in the mixing tank 5, an electric control valve 7 is installed on the discharge pipe of the mixing tank 5, and the stirring and mixing assembly 6 can fully stir and mix the material in the mixing tank 5.

[0046] In the present application, the stabilizer is any one of polyvinyl alcohol, polyethylene glycol, polydimethylsiloxane, polyethylene oxide, polypropylene oxide, carboxymethyl cellulose, sodium polyacrylate or hydroxyethyl methyl cellulose; the stabilizer can realize the modification of cerium oxide without introducing metal ions, reduce the influence of metal ions on the polishing performance of the formed polishing liquid; at the same time, the stabilizer can improve other physical properties of the polishing liquid while ensuring that its polishing performance is not affected.

[0047] In the present application, the dispersant is any one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine or histidine; it can fully make the nano cerium oxide particles uniformly dispersed.

[0048] In the present application, the polishing inhibitor is polymethacrylic acid; the PH regulator is an inorganic base or an organic base; the anionic surfactant is a carboxylate or a sulfonate; it helps to fully improve the quality of the final product.

[0049] In the present application, the anti-settling agent includes flaky particles; the average size of the flaky particles in the length direction is 0.5-3 μm, and the average size in the width direction is 0.5-3 μm; it can avoid the deposition of nano cerium oxide particles to ensure that the nano cerium oxide polishing liquid is convenient for rapid use.

[0050] In the present application, the staff prepares cerium oxide particle materials, polishing inhibitors, dispersants, anti-settling agents, stabilizers, PH regulators, anionic surfactants and deionized water according to needs, and fully ensures the quality of the materials;

[0051] The staff puts the cerium oxide particle materials into the nanoscale spheroidizing equipment 1, and fully grinds the cerium oxide particle materials through the components in the nanoscale spheroidizing equipment 1 to ensure that the cerium oxide particle materials are ground into nano cerium oxide particles; a plurality of screens are arranged at equal intervals from the feeding port to the discharging port in the nanoscale spheroidizing equipment 1, and the mesh number of the screen located on the side of the discharging port is between 120-200 meshes; the spheroidizing medium in the nanoscale spheroidizing equipment 1 is zirconium oxide beads, the diameter of the zirconium oxide beads is between 0.3-0.5 mm, and the diameter of the zirconium oxide beads in the nanoscale spheroidizing equipment 1 decreases from the feeding port to the discharging port to ensure the quality of the crushing of the cerium oxide particle materials;

[0052] The ground nano-sized cerium oxide particles and the prepared polishing inhibitor, dispersant, anti-settling agent, pH regulator, anionic surfactant and deionized water are respectively stored in a plurality of storage tanks 3, a feeding assembly 2 is installed on the storage tank 3, and an electronic metering valve assembly 4 is installed on the discharge pipe of the storage tank 3, the discharge pipe of the storage tank 3 is connected with a feeding pipe, and a mixing tank 5 is arranged through the feeding pipes; the bottom of the storage tank 3 and the mixing tank 5 are conical.

[0053] In actual production, the mass fraction of each material is: 0.1%-10% of the ground cerium oxide particles, 0.1-5% of the polishing inhibitor, 0.01-5% of the dispersant, 0.01-2% of the anti-settling agent, 0.01-2% of the stabilizer, 0.01-2% of the pH regulator, 50-500ppm of the anionic surfactant and water; the cooperation between the materials is fully ensured, the mass of each material is measured according to the quality of the final product, and the addition is facilitated; the addition of the materials can be controlled by the electronic metering valve assembly 4;

[0054] A stirring and mixing assembly 6 is installed on the mixing tank 5, the stirring and mixing assembly 6 is a double-roller stirring assembly, the double rollers in the stirring and mixing assembly 6 are spiral feeding rods, and the thread structures on the two spiral feeding rods are oppositely arranged; the lower end of the stirring and mixing assembly 6 is located in the mixing tank 5, an electric control valve 7 is installed on the discharge pipe of the mixing tank 5, and the stirring and mixing assembly 6 can fully stir and mix the materials in the mixing tank 5.

[0055] The above only describes the preferred embodiments of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical range disclosed by the present application, and all of them should be covered within the protection scope of the present application.

Claims

1. A method for preparing a nano cerium oxide polishing liquid, characterized in that, It comprises the following steps: S1, material preparation and screening: the staff prepares cerium oxide particle material, polishing inhibitor, dispersing agent, anti-settling agent, stabilizer, PH regulator, anionic surfactant and deionized water according to the needs S2, grinding and screening of the material: the staff puts the cerium oxide particle material into the nanoscale nodular equipment (1), and the components in the nanoscale nodular equipment (1) grind the cerium oxide particle material sufficiently to ensure that the cerium oxide particle material is ground into nanoscale cerium oxide particles; S3, quantitative feeding: the ground nanoscale cerium oxide particles and the prepared polishing inhibitor, dispersing agent, anti-settling agent, PH regulator, anionic surfactant and deionized water material are respectively stored in a plurality of storage tanks (3), a feeding assembly (2) is installed on the storage tank (3), and an electronic metering valve assembly (4) is installed on the discharge pipe of the storage tank (3), a feeding pipe is connected to the discharge pipe of the storage tank (3), and a mixing tank (5) is transversely arranged on the plurality of feeding pipes; S4, material mixing: a stirring and mixing assembly (6) is installed on the mixing tank (5), the lower end of the stirring and mixing assembly (6) is located in the mixing tank (5), an electric control valve (7) is installed on the discharge pipe of the mixing tank (5), and the stirring and mixing assembly (6) can fully stir and mix the material in the mixing tank (5).

2. The method according to claim 1, wherein the method comprises the steps of: (a) mixing the cerium oxide nanoparticles with the dispersant to form a mixture; (b) adding the mixture to the polishing liquid; and (c) stirring the polishing liquid. A plurality of screens are arranged at equal intervals from the feeding port to the discharge port in the nanoscale nodular equipment (1), and the screen located on the side of the discharge port has a mesh size of 120-200 meshes.

3. The method according to claim 1, wherein the method is characterized by: The stirring and mixing assembly (6) is a double-roller stirring assembly, the double rollers in the stirring and mixing assembly (6) are both spiral feeding rods, and the thread structures of the two spiral feeding rods are oppositely arranged.

4. The method for preparing a nano-cerium oxide polishing slurry according to claim 1, characterized in that: The bottoms of the storage tank (3) and the mixing tank (5) are conical.

5. The method according to claim 1, wherein the method is characterized by: The nodular medium in the nanoscale nodular equipment (1) is zirconium oxide beads, the diameter of the zirconium oxide beads is 0.3-0.5 mm, and the diameters of the zirconium oxide beads in the nanoscale nodular equipment (1) gradually decrease from the feeding port to the discharge port.

6. The method according to claim 1, wherein the method is characterized by: The stabilizer is any one of polyvinyl alcohol, polyethylene glycol, polydimethylsiloxane, polyethylene oxide, polypropylene oxide, carboxymethyl cellulose, sodium polyacrylate or hydroxyethyl methyl cellulose.

7. The method according to claim 1, wherein the method is characterized by: The dispersing agent is any one of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine or histidine.

8. The method according to claim 1, wherein the method is characterized by: The polishing inhibitor is polymethacrylic acid; the PH regulator is inorganic alkali or organic alkali; and the anionic surfactant is carboxylate or sulfonate.

9. The method according to claim 1, wherein the method is characterized by: The anti-settling agent comprises flaky particles, the average size of the flaky particles in the length direction is 0.5-3 μm, and the average size of the flaky particles in the width direction is 0.5-3 μm.

Images