Chemical mechanical polishing solution as well as preparation and application thereof
By optimizing the chemical mechanical polishing slurry and combining α-Al2O3 and γ-Al2O3 mixed abrasives with specific dispersants and additives, efficient polishing of SiC substrates was achieved, solving the problem that traditional methods are difficult to achieve nanoscale surface smoothness and improving polishing quality and removal rate.
Patent Information
- Application Number
- CN202511951882.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-03-20
AI Technical Summary
Traditional mechanical grinding or chemical etching methods are difficult to meet the global and local planarization requirements of very large-scale integrated circuits, cannot achieve the surface finish requirements at the nanometer level, and are prone to mechanical damage and uneven material removal.
A chemical mechanical polishing slurry is used, comprising a mixed abrasive dispersion, an etchant, and an additive. The mixed abrasive is a mixture of α-Al2O3 and γ-Al2O3, the dispersant is a specific polymer, and the additive is a specific compound. Through the synergistic effect of chemical and mechanical processes, easily removable reaction products are generated, thereby improving the polishing effect of SiC substrates.
Highly efficient chemical mechanical polishing of SiC substrates was achieved, with a removal rate exceeding 3.5 μm/h. The surface roughness after polishing was ≤0.1 nm, and the surface was free of pits and scratches.
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Figure CN121699501A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor processing, and particularly relates to a chemical mechanical polishing slurry and its preparation and application. Background Technology
[0002] With the rapid development of integrated circuit (IC) manufacturing technology, chip feature sizes are constantly shrinking and wiring density is continuously increasing, placing unprecedentedly stringent requirements on the flatness of wafer surfaces. In the multilayer wiring process of semiconductor devices, the deposition of each metal wiring layer and dielectric layer inevitably introduces surface undulations and defects, such as steps, trenches, and particle contamination. These uneven surfaces not only cause difficulties in light focusing and pattern transfer distortion in subsequent photolithography processes, affecting the control accuracy of critical dimensions (CD), but may also cause uneven film coverage, poor step coverage, or even short circuits or open circuits in subsequent etching, deposition, and other processes, severely reducing chip yield and reliability.
[0003] Traditional mechanical polishing or chemical etching methods are no longer sufficient to meet the dual requirements of global planarization and local planarization for ultra-large-scale integrated circuits (ULSI). While mechanical polishing can quickly remove surface material, it easily causes mechanical damage and stress on the wafer surface and has limited planarization effect on high aspect ratio structures. Simple chemical etching is usually isotropic, making it difficult to precisely control the material removal rate and surface smoothness, and thus unable to achieve the surface finish requirements at the nanometer level.
[0004] To overcome the aforementioned technical bottlenecks, Chemical Mechanical Polishing (CMP) technology emerged. CMP cleverly combines the synergistic effects of chemical etching and mechanical abrasion: during polishing, a rotating wafer is pressed onto a rotating polishing pad, while a polishing slurry is continuously supplied between them. The chemical reagents in the polishing slurry react with the wafer surface material, generating a relatively fragile and easily removable layer of reaction products; meanwhile, the mechanical abrasion action of the polishing pad continuously peels these reaction products off the wafer surface, exposing new surfaces for continued chemical reactions. This dynamic balance between chemical and mechanical actions allows CMP to achieve nanoscale or even atomic-level material removal precision, resulting in globally uniform, low-damage, and ultra-smooth wafer surfaces. It has become an indispensable key process technology in modern IC manufacturing and is widely used in the planarization of SiC substrates.
[0005] The properties of chemical mechanical polishing slurries directly affect the chemical mechanical polishing effect on SiC substrates. Optimizing and improving chemical mechanical polishing slurries to enhance the chemical mechanical polishing effect on SiC substrates is a key research focus in this field. Summary of the Invention
[0006] In view of this, the purpose of the present invention is to provide a chemical mechanical polishing slurry and its preparation and application. The polishing slurry provided by the present invention has a stable corrosion rate and can improve the chemical mechanical polishing rate and polishing quality of SiC substrates.
[0007] The present invention provides a chemical mechanical polishing slurry, the components of which include a mixed abrasive dispersion, an etchant, an additive, and water;
[0008] The mixed abrasive dispersion comprises mixed abrasive particles, a dispersant, and water; the mixed abrasive particles are a mixture of α-Al₂O₃ and γ-Al₂O₃, and the dispersant is one or more of the following: polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, phosphate copolymer, modified polyethyleneimine, acrylic acid-acrylamide copolymer ammonium salt, sodium pyrophosphate, polyvinylpyrrolidone, and perfluoroethyl ethanol polyoxyethylene ether; the content of the mixed abrasive particles in the mixed abrasive dispersion is 50-70 wt%, and the content of the dispersant is 0.3-2 wt%.
[0009] The additive is one or more of the following: perfluoroalkyl ethyl methacrylate, γ-aminopropyltriethoxysilane, trimethylphosphonic acid, polyether-modified silicone oil, diethylenetriaminepentamethylphosphonic acid, zirconium methacrylate, and sodium hexametaphosphate.
[0010] The chemical mechanical polishing slurry contains 0.1-7 wt% mixed abrasive dispersion, 1-5 wt% corrosive agent, and 0.01-0.6 wt% additives.
[0011] Preferably, the mass ratio of α-Al2O3 to γ-Al2O3 is (1.5~3):1.
[0012] Preferably, the dispersant is sodium pyrophosphate and polyvinylpyrrolidone, and the mass ratio of sodium pyrophosphate to polyvinylpyrrolidone is 1:(1.5~3).
[0013] Alternatively, the dispersant is sodium pyrophosphate and a triblock polymer of polyethylene oxide-epoxy polypropylene-polyethylene oxide, wherein the mass ratio of sodium pyrophosphate to the triblock polymer of polyethylene oxide-epoxy polypropylene-polyethylene oxide is 1:(0.5~1.5).
[0014] Alternatively, the dispersant may be a phosphate copolymer and a polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, wherein the mass ratio of the phosphate copolymer to the polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer is 1:(0.5~1.5).
[0015] Preferably, the particle size of the solid particles in the mixed abrasive dispersion is 100~500nm.
[0016] Preferably, the corrosive agent is one or more of potassium permanganate, sodium permanganate, sodium bicarbonate, sodium carbonate, cerium ammonium nitrate, and sodium stannate.
[0017] Preferably, the adjuvant is diethylenetriaminepentamethylenephosphonic acid and sodium hexametaphosphate, and the mass ratio of diethylenetriaminepentamethylenephosphonic acid to sodium hexametaphosphate is 1:(1.5~3).
[0018] Alternatively, the additive is perfluoroalkyl ethyl methacrylate and sodium hexametaphosphate, wherein the mass ratio of perfluoroalkyl ethyl methacrylate to sodium hexametaphosphate is 1:(0.5~1.5).
[0019] Alternatively, the additive is perfluoroalkyl ethyl methacrylate and zirconium methacrylate, wherein the mass ratio of perfluoroalkyl ethyl methacrylate to zirconium methacrylate is (1.5~3):1.
[0020] Preferably, the pH value of the chemical mechanical polishing solution is 8-10.
[0021] This invention provides a method for preparing the chemical mechanical polishing slurry described above, comprising the following steps:
[0022] The abrasive particles, dispersant, and water are ground and mixed to obtain a mixed abrasive particle dispersion.
[0023] The mixed abrasive dispersion, corrosive agent, additives and water are stirred and mixed to obtain a chemical mechanical polishing slurry.
[0024] This invention provides a polishing method for SiC substrates, comprising the following steps:
[0025] The SiC substrate is subjected to chemical mechanical polishing, and the polishing slurry used is the chemical mechanical polishing slurry described in the above technical solution.
[0026] Preferably, the polishing pad used in the chemical mechanical polishing is a polyurethane polishing pad.
[0027] Compared with the prior art, the present invention provides a chemical mechanical polishing slurry, its preparation, and its application. The chemical mechanical polishing slurry provided by the present invention comprises a mixed abrasive dispersion, an etchant, an additive, and water; the mixed abrasive dispersion comprises mixed abrasive particles, a dispersant, and water; the mixed abrasive particles are a mixture of α-Al₂O₃ and γ-Al₂O₃; and the dispersant is one or more selected from polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, phosphate copolymer, modified polyethyleneimine, acrylic acid-acrylamide copolymer ammonium salt, sodium pyrophosphate, polyvinylpyrrolidone, and perfluoroethyl ethanol polyoxyethylene ether. The mixed abrasive dispersion contains 50-70 wt% mixed abrasive particles and 0.3-2 wt% dispersant. The additives are one or more of perfluoroalkyl ethyl methacrylate, γ-aminopropyltriethoxysilane, trimethylphosphonic acid, polyether-modified silicone oil, diethylenetriaminepentamethylphosphonic acid, zirconium methacrylate, and sodium hexametaphosphate. The chemical mechanical polishing slurry contains 0.1-7 wt% mixed abrasive dispersion, 1-5 wt% etchant, and 0.01-0.6 wt% additives. The chemical mechanical polishing slurry provided by this invention can improve the adsorption orientation of mixed abrasive particles on the SiC surface, oxidize the SiC surface to form a soft SiO2 layer, maintain a stable corrosion rate during polishing, exhibit excellent removal rate, and achieve high polishing quality. Experimental results show that when using the polishing slurry provided by this invention for chemical mechanical polishing of SiC substrates, the removal rate is >3.5 μm / h, the surface roughness of the polished SiC substrate is ≤0.1 nm, and there are no depressions or scratches on the surface. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0029] Figure 1 This is an image of the local surface atomic force microscopy measurement results of the SiC substrate after chemical mechanical polishing provided in Embodiment 1 of the present invention;
[0030] Figure 2 This is an image showing the local surface atomic force microscopy measurement results of the SiC substrate after chemical mechanical polishing, provided in Embodiment 2 of the present invention;
[0031] Figure 3 This is an image of the local surface atomic force microscopy measurement results of the SiC substrate after chemical mechanical polishing, provided in Embodiment 3 of the present invention;
[0032] Figure 4This is an image showing the results of atomic force microscopy measurements of a local surface of a SiC substrate after chemical mechanical polishing, as provided in Embodiment 4 of the present invention. Detailed Implementation
[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0034] The present invention provides a chemical mechanical polishing slurry, the components of which include a mixed abrasive dispersion, a corrosive agent, an additive, and water; wherein the mixed abrasive dispersion comprises mixed abrasive particles, a dispersant, and water.
[0035] In the chemical mechanical polishing slurry provided by the present invention, the mixed abrasive particles are a mixture of α-Al2O3 and γ-Al2O3; the mass ratio of α-Al2O3 and γ-Al2O3 is preferably (1.5~3):1, specifically 1.5:1, 1.7:1, 2:1, 2.3:1, 2.5:1, 2.7:1 or 3:1.
[0036] In the chemical mechanical polishing slurry provided by the present invention, the content of the mixed abrasive particles in the mixed abrasive particle dispersion is 50~70wt%, specifically 50wt%, 51wt%, 52wt%, 53wt%, 54wt%, 55wt%, 56wt%, 57wt%, 58wt%, 59wt%, 60wt%, 61wt%, 62wt%, 63wt%, 64wt%, 65wt%, 66wt%, 67wt%, 68wt%, 69wt%, or 70wt%.
[0037] In the chemical mechanical polishing slurry provided by this invention, the dispersant is one or more selected from polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, phosphate copolymer, modified polyethyleneimine, ammonium salt of acrylic acid-acrylamide copolymer, sodium pyrophosphate, polyvinylpyrrolidone, and perfluoroethyl ethanol polyoxyethylene ether; wherein, the mass ratio of polyethylene oxide to epoxy polypropylene in the polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer is preferably (5~10):3, specifically 5:3, 6:3, 7:3, 8:3, 9:3, or 10:3; the dispersant is one or more selected from polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer. The degree of polymerization of the block polymer is preferably 200-300, specifically 200, 210, 220, 230, 240, 250, 260, 265, 270, 280, 290 or 300; the grade of the phosphate ester copolymer is preferably Solsperse-46000; the number average molecular weight of the polyvinylpyrrolidone is preferably 2000-8000 g / mol, specifically 2000 g / mol, 4000 g / mol, 6000 g / mol or 8000 g / mol; the modified polyethyleneimine is preferably a polyethyleneimine doubly modified with phosphonic acid groups and polypropylene oxide chains. In some embodiments provided by the present invention, the dispersant is sodium pyrophosphate and polyvinylpyrrolidone; the mass ratio of sodium pyrophosphate to polyvinylpyrrolidone is preferably 1:(1.5-3), specifically 1:1.5, 1:2, 1:2.5 or 1:3. In some embodiments of the present invention, the dispersant is sodium pyrophosphate and a poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer; the mass ratio of the sodium pyrophosphate to the poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer is preferably 1:(0.5~1.5), specifically 1:0.5, 1:0.7, 1:1, 1:1.2 or 1:1.5. In some embodiments of the present invention, the dispersant is a phosphate copolymer and a poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer; the mass ratio of the phosphate copolymer to the poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer is preferably 1:(0.5~1.5), specifically 1:0.5, 1:0.7, 1:1, 1:1.2 or 1:1.5.
[0038] In the chemical mechanical polishing slurry provided by the present invention, the content of the dispersant in the mixed abrasive dispersion is 0.3~2wt%, specifically 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, or 2wt%.
[0039] In the chemical mechanical polishing slurry provided by the present invention, the particle size of the solid material in the mixed abrasive dispersion is preferably 100~500nm, specifically 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or 500nm.
[0040] In the chemical mechanical polishing slurry provided by the present invention, the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 0.1~7wt%, specifically 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, or 7wt%.
[0041] In the chemical mechanical polishing slurry provided by the present invention, the etchant is preferably one or more of potassium permanganate, sodium permanganate, sodium bicarbonate, sodium carbonate, cerium ammonium nitrate, and sodium stannate.
[0042] In the chemical mechanical polishing slurry provided by the present invention, the content of the etchant in the chemical mechanical polishing slurry is 1~5wt%, specifically 1wt%, 1.2wt%, 1.5wt%, 1.7wt%, 2wt%, 2.3wt%, 2.5wt%, 2.7wt%, 3wt%, 3.2wt%, 3.5wt%, 3.7wt%, 4wt%, 4.2wt%, 4.5wt%, 4.7wt%, or 5wt%.
[0043] In the chemical mechanical polishing slurry provided by the present invention, the auxiliary agent is one or more selected from perfluoroalkyl ethyl methacrylate, γ-aminopropyltriethoxysilane, trimethylphosphonic acid, polyether-modified silicone oil, diethylenetriaminepentamethylphosphonic acid, zirconium methacrylate, and sodium hexametaphosphate. In some embodiments provided by the present invention, the auxiliary agent is diethylenetriaminepentamethylphosphonic acid and sodium hexametaphosphate; the mass ratio of diethylenetriaminepentamethylphosphonic acid to sodium hexametaphosphate is preferably 1:(1.5~3), specifically 1:1.5, 1:2, 1:2.5, or 1:3. In some embodiments provided by the present invention, the auxiliary agent is perfluoroalkyl ethyl methacrylate and sodium hexametaphosphate; the mass ratio of perfluoroalkyl ethyl methacrylate to sodium hexametaphosphate is preferably 1:(0.5~1.5), specifically 1:0.5, 1:0.7, 1:1, 1:1.2, or 1:1.5. In some embodiments provided by the present invention, the auxiliary agent is perfluoroalkyl ethyl methacrylate and zirconium methacrylate; the mass ratio of the perfluoroalkyl ethyl methacrylate and zirconium methacrylate is preferably (1.5~3):1, specifically 1.5:1, 2:1, 2.5:1 or 3:1.
[0044] In the chemical mechanical polishing slurry provided by the present invention, the content of the auxiliary agent in the chemical mechanical polishing slurry is 0.01~0.6wt%, specifically 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.07wt%, 0.1wt%, 0.12wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.4wt%, 0.5wt%, or 0.6wt%.
[0045] In the chemical mechanical polishing slurry provided by the present invention, the pH value of the chemical mechanical polishing slurry is preferably 8 to 10, specifically 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, 9.02, 9.1, 9.2, 9.3, 9.35, 9.4, 9.5, 9.6, 9.65, 9.68, 9.7, 9.8, 9.9 or 10.
[0046] The present invention also provides a method for preparing the chemical mechanical polishing slurry described in the above technical solution, comprising the following steps:
[0047] The abrasive particles, dispersant, and water are ground and mixed to obtain a mixed abrasive particle dispersion.
[0048] The mixed abrasive dispersion, corrosive agent, additives and water are stirred and mixed to obtain a chemical mechanical polishing slurry.
[0049] The present invention also provides a polishing method for a SiC substrate, comprising the following steps:
[0050] The SiC substrate is subjected to chemical mechanical polishing, and the polishing slurry used is the chemical mechanical polishing slurry described in the above technical solution.
[0051] In the polishing method provided by the present invention, the polishing pad used for chemical mechanical polishing is preferably a polyurethane polishing pad; the Shore hardness of the polishing pad is preferably 75 to 95, specifically 75, 80, 85, 90 or 95.
[0052] In the polishing method provided by this invention, the upper plate rotation speed of the polishing equipment used for chemical mechanical polishing is preferably 10~60 rpm, specifically 10 rpm, 15 rpm, 20 rpm, 25 rpm, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm, 55 rpm, or 60 rpm; the lower plate rotation speed of the polishing equipment is preferably 6~40 rpm, specifically 6 rpm, 8 rpm, 10 rpm, 12 rpm, 15 rpm, 20 rpm, 25 rpm, 30 rpm, 35 rpm, or 40 rpm; the polishing disc pressure of the polishing equipment is preferably 80~500 kg, specifically 80 kg, 100 kg, 120 kg, 150 kg, 200 kg, 250 kg, 300 kg, 400 kg, or 500 kg.
[0053] In the polishing method provided by the present invention, the flow rate of the polishing liquid for chemical mechanical polishing is preferably 7~10L / min, specifically 7L / min, 7.2L / min, 7.5L / min, 7.7L / min, 8L / min, 8.2L / min, 8.5L / min, 8.7L / min, 9L / min, 9.2L / min, 9.5L / min, 9.7L / min or 10L / min.
[0054] In the polishing method provided by the present invention, the chemical mechanical polishing time is preferably 60~240 min, specifically 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min, 200 min, 220 min or 240 min.
[0055] For clarity, the following examples and comparative models will be used to provide a detailed description.
[0056] Example 1
[0057] Step 1: Select a mixed abrasive with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix it with sodium pyrophosphate, polyvinylpyrrolidone (number average molecular weight 4000 g / mol) and deionized water to obtain a mixed abrasive dispersion; the mixed abrasive dispersion contains 60 wt% mixed abrasive, 0.5 wt% sodium pyrophosphate, and 1.0 wt% polyvinylpyrrolidone, and the solid particle size in the dispersion is 100~500 nm.
[0058] Step 2: The prepared mixed abrasive dispersion is stirred and mixed with diethylenetriaminepentamethylenephosphonic acid, sodium hexametaphosphate, potassium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of diethylenetriaminepentamethylenephosphonic acid is 0.01wt%, the content of sodium hexametaphosphate is 0.02wt%, the content of potassium permanganate is 2wt%, and the pH value of the polishing slurry is 9.35.
[0059] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0060] The results showed that the removal rate of the SiC substrate was 3.6 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.071 nm.
[0061] The results of local surface atomic force microscopy measurements of the SiC substrate after chemical mechanical polishing are as follows: Figure 1 As shown.
[0062] Example 2
[0063] Step 1: Select a mixed abrasive with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix it with sodium pyrophosphate, a poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer (poly(ethylene oxide) to epoxy polypropylene mass ratio of 70wt%:30wt%, total degree of polymerization of 265) and deionized water to obtain a mixed abrasive dispersion; the mixed abrasive dispersion contains 60wt% mixed abrasive, 0.5wt% sodium pyrophosphate, and 0.5wt% poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer, and the solid particle size in the dispersion is 100~500nm.
[0064] Step 2: The prepared mixed abrasive dispersion is mixed with perfluoroalkyl ethyl methacrylate, sodium hexametaphosphate, potassium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of perfluoroalkyl ethyl methacrylate is 0.02wt%, the content of sodium hexametaphosphate is 0.02wt%, the content of potassium permanganate is 2wt%, and the pH value of the polishing slurry is 9.65.
[0065] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0066] The results showed that the removal rate of the SiC substrate was 3.72 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.073 nm.
[0067] The results of local surface atomic force microscopy measurements of the SiC substrate after chemical mechanical polishing are as follows: Figure 2 As shown.
[0068] Example 3
[0069] Step 1: Select a mixed abrasive with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix it with a phosphate copolymer (Solsperse-46000), a polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer (polyethylene oxide to epoxy polypropylene mass ratio of 70wt%:30wt%, total degree of polymerization of 265), and deionized water to obtain a mixed abrasive dispersion; the mixed abrasive dispersion contains 60wt% mixed abrasive, 0.5wt% phosphate copolymer, and 0.5wt% polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, and the solid particle size in the dispersion is 100~500nm.
[0070] Step 2: The prepared mixed abrasive dispersion is stirred and mixed with perfluoroalkyl ethyl methacrylate, zirconium methacrylate, potassium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of perfluoroalkyl ethyl methacrylate is 0.02wt%, the content of zirconium methacrylate is 0.01wt%, the content of potassium permanganate is 2wt%, and the pH value of the polishing slurry is 9.02.
[0071] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0072] The results showed that the removal rate of the SiC substrate was 3.52 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.070 nm.
[0073] The results of local surface atomic force microscopy measurements of the SiC substrate after chemical mechanical polishing are as follows: Figure 3 As shown.
[0074] Example 4
[0075] Step 1: Select a mixed abrasive with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix it with sodium pyrophosphate, a poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer (poly(ethylene oxide) to epoxy polypropylene mass ratio of 70wt%:30wt%, total degree of polymerization of 265) and deionized water to obtain a mixed abrasive dispersion; the mixed abrasive dispersion contains 60wt% mixed abrasive, 0.5wt% sodium pyrophosphate, and 0.5wt% poly(ethylene oxide)-epoxy polypropylene-poly(ethylene oxide) triblock polymer, and the solid particle size in the dispersion is 100~500nm.
[0076] Step 2: The prepared mixed abrasive dispersion is stirred and mixed with perfluoroalkyl ethyl methacrylate, sodium hexametaphosphate, sodium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of perfluoroalkyl ethyl methacrylate is 0.02wt%, the content of sodium hexametaphosphate is 0.02wt%, the content of sodium permanganate is 2wt%, and the pH value of the polishing slurry is 9.68.
[0077] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0078] The results showed that the removal rate of the SiC substrate was 3.75 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.071 nm.
[0079] The results of local surface atomic force microscopy measurements of the SiC substrate after chemical mechanical polishing are as follows: Figure 4 As shown.
[0080] Comparative Example 1
[0081] Step 1: Select a mixed abrasive particles with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix them with deionized water to obtain a mixed abrasive particle dispersion; the mixed abrasive particle content in the mixed abrasive particle dispersion is 60wt%, and the particle size of the solid particles in the dispersion is 100~500nm.
[0082] Step 2: The prepared mixed abrasive dispersion is stirred and mixed with diethylenetriaminepentamethylenephosphonic acid, sodium hexametaphosphate, potassium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of diethylenetriaminepentamethylenephosphonic acid is 0.01wt%, the content of sodium hexametaphosphate is 0.02wt%, the content of potassium permanganate is 2wt%, and the pH value of the polishing slurry is 9.12.
[0083] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0084] The results showed that the removal rate of the SiC substrate was 2.83 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.128 nm.
[0085] Comparative Example 2
[0086] Step 1: Select a mixed abrasive with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix it with sodium pyrophosphate, polyvinylpyrrolidone (number average molecular weight 4000 g / mol) and deionized water to obtain a mixed abrasive dispersion; the mixed abrasive dispersion contains 60 wt% mixed abrasive, 0.5 wt% sodium pyrophosphate, and 1.0 wt% polyvinylpyrrolidone, and the solid particle size in the dispersion is 100~500 nm.
[0087] Step 2: Mix the prepared mixed abrasive dispersion with potassium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of potassium permanganate is 2wt%, and the pH value of the polishing slurry is 9.23.
[0088] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0089] The results showed that the removal rate of the SiC substrate was 2.95 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.234 nm.
[0090] Comparative Example 3
[0091] Step 1: Select a mixed abrasive particles with a mass ratio of α-Al2O3 to γ-Al2O3 of 3:1, and grind and mix them with deionized water to obtain a mixed abrasive particle dispersion; the mixed abrasive particle content in the mixed abrasive particle dispersion is 60wt%, and the particle size of the solid particles in the dispersion is 100~500nm.
[0092] Step 2: Mix the prepared mixed abrasive dispersion with potassium permanganate and deionized water to obtain a chemical mechanical polishing slurry; the content of the mixed abrasive dispersion in the chemical mechanical polishing slurry is 3wt%, the content of potassium permanganate is 2wt%, and the pH value of the polishing slurry is 8.05.
[0093] Step 3: Perform chemical mechanical polishing (CMP) on the SiC substrate after coarse and fine grinding using the prepared CMP slurry. The initial surface roughness of the SiC substrate is 20 nm. The polishing pad is a grid-shaped polyurethane polishing pad with a Shore hardness of 85. The upper plate rotation speed of the polishing equipment is 30 rpm, the lower plate rotation speed is 15 rpm, the polishing plate pressure is 200 kg, the polishing slurry flow rate is 8 L / min, and the polishing time is 120 min.
[0094] The results showed that the removal rate of the SiC substrate was 2.05 nm / h, and the surface roughness of the substrate after chemical mechanical polishing was 0.361 nm.
[0095] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A chemical mechanical polishing slurry, characterized in that, The chemical mechanical polishing slurry comprises a mixed abrasive dispersion, an etchant, an additive, and water; The mixed abrasive dispersion comprises mixed abrasive particles, a dispersant, and water; the mixed abrasive particles are a mixture of α-Al₂O₃ and γ-Al₂O₃, and the dispersant is one or more selected from polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, phosphate copolymer, modified polyethyleneimine, acrylic acid-acrylamide copolymer ammonium salt, sodium pyrophosphate, polyvinylpyrrolidone, and perfluoroethyl ethanol polyoxyethylene ether; the content of the mixed abrasive particles in the mixed abrasive dispersion is 50-70 wt%, and the content of the dispersant is 0.3-2 wt%. The additive is one or more of the following: perfluoroalkyl ethyl methacrylate, γ-aminopropyltriethoxysilane, trimethylphosphonic acid, polyether-modified silicone oil, diethylenetriaminepentamethylphosphonic acid, zirconium methacrylate, and sodium hexametaphosphate. The chemical mechanical polishing slurry contains 0.1-7 wt% mixed abrasive dispersion, 1-5 wt% corrosive agent, and 0.01-0.6 wt% additives.
2. The chemical mechanical polishing slurry according to claim 1, characterized in that, The mass ratio of α-Al2O3 to γ-Al2O3 is (1.5~3):
1.
3. The chemical mechanical polishing slurry according to claim 1, characterized in that, The dispersant is sodium pyrophosphate and polyvinylpyrrolidone, and the mass ratio of sodium pyrophosphate to polyvinylpyrrolidone is 1:(1.5~3). Alternatively, the dispersant is sodium pyrophosphate and a triblock polymer of polyethylene oxide-epoxy polypropylene-polyethylene oxide, wherein the mass ratio of sodium pyrophosphate to the triblock polymer of polyethylene oxide-epoxy polypropylene-polyethylene oxide is 1:(0.5~1.5). Alternatively, the dispersant may be a phosphate copolymer and a polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer, wherein the mass ratio of the phosphate copolymer to the polyethylene oxide-epoxy polypropylene-polyethylene oxide triblock polymer is 1:(0.5~1.5).
4. The chemical mechanical polishing slurry according to claim 1, characterized in that, The solid particle size in the mixed abrasive dispersion is 100~500nm.
5. The chemical mechanical polishing slurry according to claim 1, characterized in that, The corrosive agent is one or more of potassium permanganate, sodium permanganate, sodium bicarbonate, sodium carbonate, cerium ammonium nitrate, and sodium stannate.
6. The chemical mechanical polishing slurry according to claim 1, characterized in that, The adjuvant is diethylenetriaminepentamethylenephosphonic acid and sodium hexametaphosphate, and the mass ratio of diethylenetriaminepentamethylenephosphonic acid and sodium hexametaphosphate is 1:(1.5~3). Alternatively, the additive is perfluoroalkyl ethyl methacrylate and sodium hexametaphosphate, wherein the mass ratio of perfluoroalkyl ethyl methacrylate to sodium hexametaphosphate is 1:(0.5~1.5). Alternatively, the additive is perfluoroalkyl ethyl methacrylate and zirconium methacrylate, wherein the mass ratio of perfluoroalkyl ethyl methacrylate to zirconium methacrylate is (1.5~3):
1.
7. The chemical mechanical polishing slurry according to claim 1, characterized in that, The pH value of the chemical mechanical polishing fluid is 8-10.
8. A method for preparing the chemical mechanical polishing slurry according to any one of claims 1 to 7, characterized in that, Includes the following steps: The abrasive particles, dispersant, and water are ground and mixed to obtain a mixed abrasive particle dispersion. The mixed abrasive dispersion, corrosive agent, additives and water are stirred and mixed to obtain a chemical mechanical polishing slurry.
9. A polishing method for a SiC substrate, characterized in that, Includes the following steps: The SiC substrate is subjected to chemical mechanical polishing, and the polishing slurry used is the chemical mechanical polishing slurry according to any one of claims 1 to 7.
10. The polishing method according to claim 9, characterized in that, The polishing pad used in the chemical mechanical polishing is a polyurethane polishing pad.