A square cerium oxide composite material, its preparation method and application

Abstract

The present invention discloses a square cerium oxide composite material, a preparation method thereof and an application thereof. A preparation method of a square cerium oxide composite material includes the following steps: S1 Mix a cerium salt, a praseodymium salt and / or a neodymium salt in water, sequentially add an inorganic acid and an organic acid, then add ammonia water and an ammonium salt, and heat and react to obtain a mixed solution; S2 Adjust the pH of the mixed solution to be acidic, and carry out a sol-gel reaction to obtain the square cerium oxide composite material; in step S1, the temperature of the heating reaction is 30°C - 100.0°C; in step S1, the heating reaction is carried out under a high pressure of 20 - 25 MPa. The square cerium oxide composite material of the present invention has a square morphology with regular, uniform and concentrated shape, a crystallinity of greater than or equal to 95%, and a purity of greater than or equal to 99.999%.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and particularly relates to a square cerium oxide composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Cerium oxide is an important chemical compound, belonging to rare earth metal oxides and being one of the oxide forms of cerium. It is a white or light yellow powder and is widely used in multiple industrial fields, especially occupying an important position in industries such as semiconductors, optics, chemistry, and cosmetics. Cerium oxide has very unique physical and chemical properties, especially its excellent performance in catalytic and polishing applications, making it widely used in cutting-edge science and technology fields.

[0003] Square cerium oxide (also known as cubic cerium oxide) has relatively unique structures and properties. The crystal structure of cerium oxide at room temperature is cubic (lattice parameter is 5.411 Å), and it has relatively strong thermal stability, high chemical activity, and unique nano characteristics. Traditional cerium oxide presents irregularly shaped particles, or certain elongated shapes, prismatic shapes, etc. Although these shapes are effective in some applications, in some nano-scale processing and ultra-high-performance applications, regular-shaped cerium oxide, especially square cerium oxide, has superior properties. Due to its regular geometric shape, square cerium oxide particles can be better evenly distributed in coatings or polishing materials, reducing material waste and the processing difficulty brought by irregular particles while maintaining a high polishing effect, so it is particularly important in the fields of precision polishing and chemical mechanical planarization (CMP).

[0004] The application scope of cerium oxide is very wide, especially in the fields of semiconductor CMP (chemical mechanical planarization), high-end optical polishing, and cosmetics. Cerium oxide is commonly used in the CMP process in semiconductor manufacturing because of its excellent chemical activity and relatively soft characteristics, which can polish (planarize) key semiconductor processes such as silicon wafers, ILD dielectric layers, and STI at high speed with relatively few defects. This characteristic makes cerium oxide an ideal CMP polishing material, especially when manufacturing semiconductors below 14 nanometers, which can improve processing efficiency while precisely controlling surface quality, thereby improving the reliability and performance of products.

[0005] In high-end optical polishing, cerium oxide is also widely used. High-end optical polishing requires very high precision and surface quality to ensure the optical performance of the final optical products. The polishing effect of cerium oxide can make the surfaces of optical glass, optical lenses, laser devices, etc. reach a high degree of flatness, reducing surface defects, thereby improving optical performance. Due to its high optical transparency and low light absorption, cerium oxide has become an indispensable polishing material in the high-end optical field.

[0006] In the field of cosmetics, the application of cerium oxide is mainly reflected in its use as a cosmetic raw material, especially in products such as foundation, moisturizing cream, and sunscreen. Cerium oxide can effectively protect the skin from ultraviolet damage due to its good ultraviolet resistance characteristics. In addition, the low allergenicity and good skin adaptability of cerium oxide also enable it to be widely used in personal care products.

[0007] Traditionally, the preparation methods of cerium oxide include roasting method, sol-gel method, precipitation method, etc. These methods are widely used in industrial production. The roasting method usually involves heating the cerium precursor at high temperature to make it undergo an oxidation reaction to obtain cerium oxide. The traditional sol-gel method dissolves the cerium compound in a solvent, then adds appropriate chemical reagents to react to obtain a precursor, and finally obtains cerium oxide powder through drying and roasting. The precipitation method is to add an excessive precipitant in the liquid phase to precipitate the cerium precursor, and then obtain cerium oxide through filtration with filter paper, drying, and roasting.

[0008] However, traditional preparation methods often encounter some challenges when preparing cerium oxide with high crystallinity. First of all, the cerium oxide obtained by conventional methods has a low crystallinity, mainly because during the roasting process at high temperature, the cerium oxide particles often grow too rapidly, resulting in low crystallinity. In addition, due to the possible use of a large amount of solvents and chemical reagents in the precipitation method and sol-gel method, it is easy to cause the incorporation of impurities, which will hinder the crystallization process of cerium oxide, and finally make the obtained cerium oxide have low purity and poor crystallinity.

[0009] The particle shape of cerium oxide prepared by conventional methods is usually irregular, with poor uniformity and rough surface. Especially in the roasting method, due to the oxidation reaction of cerium under high temperature conditions being often a non-uniform process, the particle shape is irregular. In addition, in the precipitation method and sol-gel method, although the particle size can be adjusted by controlling the reaction conditions, due to the fast reaction speed and improper temperature control, irregularly shaped particles are usually obtained. The shape, particle size distribution, and surface properties of these particles have a certain impact on the application performance of cerium oxide. Especially in high-end applications, this irregularity and low purity will greatly reduce its polishing effect and other properties.

[0010] Based on this, it is urgent to develop a new cerium oxide composite material so that the morphology of cerium oxide is square, with regular, uniform, and concentrated shape, good crystallinity, and high purity, which can be widely used in fields such as semiconductor CMP polishing, high-end optical polishing, and cosmetics. Summary of the Invention

[0011] The purpose of the present invention is to provide a cerium oxide composite material with a square morphology, regular, uniform, and concentrated shape, good crystallinity, and high purity.

[0012] The first aspect of the present invention lies in:

[0013] Providing a method for preparing a square cerium oxide composite material.

[0014] The second aspect of the present invention lies in:

[0015] Providing a square cerium oxide composite material.

[0016] The third aspect of the present invention lies in:

[0017] The application of the square cerium oxide composite material.

[0018] The present invention also proposes a semiconductor polishing material, which comprises the square cerium oxide composite material.

[0019] The present invention also proposes an optical polishing material, which comprises the square cerium oxide composite material.

[0020] The present invention also proposes a cosmetic, which comprises the square cerium oxide composite material.

[0021] Specifically, the technical solution adopted according to the first aspect of the present invention is as follows:

[0022] S1 Mix cerium salts, praseodymium salts and / or neodymium salts in water, sequentially add inorganic acids and organic acids, and then add ammonia water and ammonium salts;

[0023] S2 Adjust the pH of the mixed solution to be acidic, and obtain the square cerium oxide composite material through a sol-gel reaction;

[0024] In step S1, the temperature of the heating reaction is 30°C - 100.0°C;

[0025] In step S1, the heating reaction is carried out under a high pressure of 20 - 25 MPa.

[0026] According to the embodiments of the present invention, at least one of the following advantages or beneficial effects exists in one of the technical solutions in the technical solution:

[0027] By mixing cerium salts, praseodymium salts and / or neodymium salts, sequentially adding inorganic acids and organic acids, and adding ammonia water and ammonium salts, cerium ions and other metal ions can be effectively coordinated and arranged, promoting the directional growth of crystals to form particles with a regular square morphology; the present invention controls the pH to be acidic to promote the formation of particles with a regular square morphology, making the reaction more controllable, and the nucleation and growth of crystal grains more uniform; controlling the temperature and pressure of the heating reaction ensures that the particle size and impurity content of the product meet the requirements; in addition, the addition of ammonia water also controls the formation rate of cerium oxide, making the formed nanocrystals highly regular, and the adjustment of acids and ammonia water also helps to control the agglomeration of particles to form a more uniform composite material.

[0028] In addition, when using the sol-gel method, cerium ions form a nano-scale gel network through hydrolysis reactions, and through repeated dehydration and hydrolysis reactions during the heating process, they are finally transformed into uniform cerium oxide composite nanoparticles. The sol-gel method can achieve relatively uniform particle growth and smaller grain sizes, which helps to control the shape and crystallinity of the material;

[0029] Praseodymium and / or neodymium rare earth metal ions within the cerium oxide unit cell help to stabilize the lattice structure, promote crystal growth, and thus improve crystallinity. Higher crystallinity helps to reduce defects, and further improves the morphology of the material.

[0030] According to an embodiment of the present invention, a method for preparing the square cerium oxide composite includes the following steps: mixing a cerium salt, a praseodymium salt and / or a neodymium salt, and water in a reaction device, adding an inorganic acid, an organic acid, ammonia water, and an ammonium salt, and heating and reacting to obtain a mixed solution.

[0031] According to an embodiment of the present invention, a method for preparing the square cerium oxide composite includes the following process: the cerium salt, the praseodymium salt and / or the neodymium salt (denoted as CeX, PrX, and / or NdX) first react with the organic acid (denoted as HR1) and the inorganic acid (denoted as HR2) to generate R1CeR2, R1PrR2, and / or R1NdR2. Subsequently, R1CeR2, R1PrR2, and / or R1NdR2 react with ammonia water through a sol-gel reaction to generate CeO2, PrO2, and / or NdO2, CO2, N2, and H2O, where CeO2, PrO2, and / or NdO2 are the square cerium oxide composites.

[0032] According to an embodiment of the present invention, a schematic diagram of the method for preparing the square cerium oxide composite is as Figure 1 shown.

[0033] According to an embodiment of the present invention, the volume ratio of the inorganic acid, the organic acid, and water is 2:1:100 - 2800.

[0034] According to an embodiment of the present invention, the mass ratio of water, ammonia water, and ammonium salt is 50 - 100:4:2.

[0035] According to an embodiment of the present invention, the mass ratio of the cerium salt to water is 1:100 - 20000. When the mass ratio of the cerium salt to water is not within this range, it will result in too high or too low reaction rates, and ultimately lead to the product not taking shape.

[0036] According to an embodiment of the present invention, in step S2, the sol-gel reaction includes the following steps: subjecting the mixed solution to distillation and concentration at 30°C - 160°C. During the sol-gel process, factors such as the pH value, temperature, and reaction time of the solution will affect the shape of the particles. In the present invention, controlling the pH to be acidic is beneficial to promoting uniform precipitation and particle formation.

[0037] According to an embodiment of the present invention, the distillation and concentration is high-pressure distillation and concentration, and the pressure range is 1 - 200 MPa, preferably 1 - 20 MPa, and more preferably 20 MPa.

[0038] According to an embodiment of the present invention, in step S2, after the mixed solution undergoes the sol-gel reaction, the following steps are further included: subjecting the product obtained after the sol-gel reaction to concentration at 120°C - 180°C until the solid content ≥ 60.0%, centrifuging to obtain a precipitate, and drying the precipitate to obtain the square cerium oxide composite material.

[0039] According to an embodiment of the present invention, the drying of the precipitate includes the following steps: drying the precipitate at a high temperature of 300°C - 1100°C for 2 - 12 hours to obtain the square cerium dioxide composite material.

[0040] According to an embodiment of the present invention, the method for preparing the square cerium oxide composite material further includes the following step: after drying the precipitate, performing a deagglomeration operation to obtain a nano-square cerium oxide composite material powder.

[0041] According to an embodiment of the present invention, in step S2, the pH of the mixed solution is adjusted to be acidic, and the pH is 1.0 - 6.5. Preferably, the pH is 3.5 - 6.5.

[0042] Specifically, the technical solution adopted in the second aspect of the present invention is as follows:

[0043] A square cerium oxide composite material prepared by the method described above, and the raw materials for preparing the cerium oxide composite material include the following components:

[0044] Cerium salt;

[0045] Praseodymium salt and / or neodymium salt;

[0046] Ammonia water;

[0047] Ammonium salt;

[0048] Organic acid;

[0049] Inorganic acid;

[0050] Water.

[0051] According to an embodiment of the present invention, at least one of the technical solutions in the above technical solutions has the following advantages or beneficial effects:

[0052] The square cerium oxide composite material of the present invention is a composite material of cerium oxide, praseodymium oxide and / or neodymium oxide. Its morphology is square, regular, uniform and concentrated. The crystallinity of the square cerium oxide composite material is greater than or equal to 95%, and the purity is greater than or equal to 99.999% of the cerium oxide composite material.

[0053] According to an embodiment of the present invention, the molar ratio of cerium ions to praseodymium ions in the cerium salt and praseodymium salt is 100-1000000:1; the molar ratio of cerium ions to neodymium ions in the cerium salt and neodymium salt is 100-1000000:1. When the molar ratio of cerium ions to praseodymium ions or the molar ratio of cerium ions to neodymium ions is not within the above range, the product particles will not form and become irregular products.

[0054] According to an embodiment of the present invention, the molar ratio of cerium ions to praseodymium ions in the cerium salt and praseodymium salt is 4000-80000:1. Preferably, it is 80000:1.

[0055] According to an embodiment of the present invention, the molar ratio of cerium ions to neodymium ions in the cerium salt and neodymium salt is 4000-80000:1. Preferably, it is 80000:1.

[0056] According to an embodiment of the present invention, the addition of praseodymium salt and / or neodymium salt directly contributes to the hardness and impurity content of the product. However, if praseodymium salt and / or neodymium salt are not added, the product hardness will decrease and the impurity content will increase, and it can no longer be used in semiconductor polishing materials.

[0057] According to an embodiment of the present invention, the cerium salt includes at least one of Ce2(CO3)3, Ce(NO3)3, CeCl3 and Ce2(SO4)3.

[0058] According to an embodiment of the present invention, the praseodymium salt includes at least one of Pr2(CO3)3, Pr(NO3)3, PrCl3 and Pr2(SO4)3.

[0059] According to an embodiment of the present invention, the neodymium salt includes at least one of Nd2(CO3)3, Nd(NO3)3, NdCl3 and Nd2(SO4)3.

[0060] According to an embodiment of the present invention, the purity of the cerium salt, praseodymium salt and neodymium salt is ≥99.999%.

[0061] According to an embodiment of the present invention, the organic acid includes at least one of formic acid, acetic acid, n-butyric acid, n-hexanoic acid and oxalic acid.

[0062] According to an embodiment of the present invention, the organic acid is acetic acid.

[0063] According to an embodiment of the present invention, the ammonium salt is selected from at least one of ammonium nitrate, ammonium phosphate, ammonium sulfate, ammonium acetate, and ammonium chloride.

[0064] According to an embodiment of the present invention, the ammonium salt is ammonium nitrate.

[0065] According to an embodiment of the present invention, the inorganic acid is nitric acid.

[0066] According to an embodiment of the present invention, the concentration of the ammonia water is 1% - 70% w / w.

[0067] According to an embodiment of the present invention, the molar ratio of the ammonia water to the ammonium salt is 1:0.5 - 0.01.

[0068] Another aspect of the present invention further provides a semiconductor polishing material, including the square cerium oxide composite material as described in the embodiment of the first aspect above. Since this application adopts all the technical solutions of the above square cerium oxide composite material, it has at least all the beneficial effects brought by the technical solutions of the above embodiments.

[0069] According to an embodiment of the present invention, a method for semiconductor polishing includes the following steps:

[0070] Fix the wafer to be polished on the polishing platen, start the polishing equipment, and prepare the semiconductor polishing material into a polishing liquid and spray it onto the surface of the polishing pad for polishing.

[0071] According to an embodiment of the present invention, the polishing liquid has the following components in parts by weight:

[0072] Abrasive, 1.5 - 3.0 parts;

[0073] Ultra-pure water, 85.0 - 90.0 parts;

[0074] Oxidizing agent, 0.5 - 1 part;

[0075] Complexing agent, 1.0 - 2.0 parts;

[0076] Corrosion inhibitor, 0.1 - 0.5 part;

[0077] Surfactant, 0.2 - 0.4 part;

[0078] pH regulator, 0.2 - 0.3 part.

[0079] According to an embodiment of the present invention, the abrasive includes the square cerium oxide composite material as described in the embodiment of the first aspect above.

[0080] According to an embodiment of the present invention, the oxidant includes potassium permanganate and / or hydrogen peroxide. The oxidant can promote chemical reactions and accelerate material removal.

[0081] According to an embodiment of the present invention, the complexing agent includes glutamic acid and / or acetyl amino acid. The complexing agent can form complexes to stabilize metal ions in the solution and prevent their precipitation.

[0082] According to an embodiment of the present invention, the corrosion inhibitor includes ammonia water. The corrosion inhibitor can reduce the corrosion of the areas that do not need to be polished and protect the material surface.

[0083] According to an embodiment of the present invention, the surfactant includes polyethylene ether. The surfactant can reduce the surface tension and improve the wettability and dispersibility of the polishing liquid.

[0084] According to an embodiment of the present invention, the pH regulator includes citrate. The pH regulator can adjust the pH value of the solution and optimize the chemical reaction conditions during the polishing process.

[0085] Another aspect of the present invention also provides an optical polishing material. It includes the square cerium oxide composite material as described in the embodiment of the first aspect above. Since this application adopts all the technical solutions of the above-mentioned square cerium oxide composite material, it has at least all the beneficial effects brought by the technical solutions of the above embodiments.

[0086] Another aspect of the present invention also provides a cosmetic. It includes the square cerium oxide composite material as described in the embodiment of the first aspect above. Since this application adopts all the technical solutions of the above-mentioned square cerium oxide composite material, it has at least all the beneficial effects brought by the technical solutions of the above embodiments.

[0087] Other features and advantages of the present invention will be described in the subsequent specification, and some of them will become obvious from the specification or be understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0089] Figure 1 It is a schematic flow chart of the preparation method of the square cerium oxide composite material in Example 1.

[0090] Figure 2 It is an SEM image of the cerium oxide composite powder obtained in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0091] The terms "preferred", "more preferred", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain cases. However, in the same or other cases, other embodiments may also be preferred. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

[0092] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as each value therebetween. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0093] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

[0094] The reagents, methods, and equipment used in the present invention, unless otherwise specified, are all conventional reagents, methods, and equipment in the technical field.

[0095] Example 1

[0096] A square cerium oxide composite material, and the raw materials of the cerium oxide composite material include the following components:

[0097] Cerium nitrate;

[0098] Praseodymium nitrate;

[0099] Neodymium nitrate;

[0100] Ammonia water;

[0101] Ammonium nitrate;

[0102] Acetic acid;

[0103] Nitric acid;

[0104] Water.

[0105] To prepare the above square cerium oxide composite material, the following steps are included:

[0106] S1 Dissolve cerium nitrate in water, then add praseodymium nitrate and neodymium nitrate and stir until a transparent and clear solution is obtained. The molar ratio of cerium ions to praseodymium ions and neodymium ions is 80000:1:1, and the mass ratio of cerium salt to water is 1:200;

[0107] S2 Then add nitric acid and acetic acid in sequence and stir until a transparent and clear solution is obtained. The volume ratio of nitric acid, acetic acid to water is 2:1:200; Add ammonia water and ammonium salt. The mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water to ammonium salt is 1:0.21 to obtain a mixed solution;

[0108] S3 Place the mixed solution in a reaction at 55.0 °C and 20 MPa under high pressure for 20 hours, adjust the pH to 3.5 to obtain a square cerium oxide composite material.

[0109] The preparation of square cerium oxide composite powder includes the following steps:

[0110] A1 Place the square cerium oxide composite material prepared in step S3 under high temperature and reduced pressure concentration at 120 °C to make the cerium dioxide concentration reach 5% w / w. The particle size of the square cerium dioxide composite material particles is 30 - 40 nm;

[0111] A2 Concentrate the product of step A1 at 145 °C until the solid content of the composite material is 95.0% w / w, then centrifuge to obtain a precipitate, and dry the precipitate at 300 °C for 8 hours and deagglomerate to obtain square cerium oxide composite powder.

[0112] The process flow diagram for preparing the square cerium oxide composite material and cerium oxide composite powder in Example 1 is as Figure 1 shown. The SEM image of the cerium oxide composite powder prepared in Example 1 is as Figure 2 shown.

[0113] Example 2

[0114] The difference between Example 2 and Example 1 is that in Example 2, the cerium salt is cerium chloride, the praseodymium salt is praseodymium chloride, and the neodymium salt is neodymium chloride.

[0115] Specifically:

[0116] A square cerium oxide composite material, the raw materials of the above cerium oxide composite material include the following components:

[0117] Cerium chloride;

[0118] Praseodymium chloride;

[0119] Neodymium chloride;

[0120] Ammonia water;

[0121] Ammonium nitrate;

[0122] Acetic acid;

[0123] Nitric acid;

[0124] Water.

[0125] The preparation of the above-mentioned square cerium oxide composite material comprises the following steps:

[0126] S1 Dissolve cerium chloride in water, then add praseodymium chloride and neodymium chloride and stir to form a transparent and clear solution. The molar ratio of cerium ions to praseodymium ions and neodymium ions is 80000:1:1, and the mass ratio of cerium salt to water is 1:200;

[0127] S2 Then add nitric acid and acetic acid in sequence and stir to form a transparent and clear solution. The volume ratio of nitric acid, acetic acid to water is 2:1:200; Add ammonia water and ammonium salt. The mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water to ammonium salt is 1:0.21 to obtain a mixed solution;

[0128] S3 Place the mixed solution under a high pressure of 55.0 °C and 20 MPa and react for 20 hours, adjust the pH to 3.5 to obtain a square cerium oxide composite material.

[0129] The preparation of the cerium oxide composite material powder comprises the following steps:

[0130] A1 Place the square cerium oxide composite material prepared in step S3 under high temperature and reduced pressure concentration at 120 °C to make the cerium dioxide concentration reach 5% w / w. The particle size of the square cerium dioxide composite material particles is 30 - 40 nm;

[0131] A2 Concentrate the product of step A1 at 145 °C until the solid content of the composite material is 95.0% w / w, then centrifuge to obtain a precipitate, and place the precipitate in a high temperature drying oven at 300 °C for 8 hours. After deagglomeration, a square cerium oxide composite material powder is obtained.

[0132] Example 3

[0133] The difference between Example 3 and Example 1 is that in Example 3, the cerium salt is cerium carbonate, the praseodymium salt is praseodymium carbonate, and the neodymium salt is neodymium carbonate.

[0134] Specifically:

[0135] A square cerium oxide composite material, the raw materials of the above-mentioned cerium oxide composite material include the following components:

[0136] Cerium carbonate;

[0137] Praseodymium carbonate;

[0138] Neodymium carbonate;

[0139] Ammonia water;

[0140] Ammonium nitrate;

[0141] Acetic acid;

[0142] Nitric acid;

[0143] Water.

[0144] To prepare the above-mentioned square cerium oxide composite material, the following steps are included:

[0145] S1 Dissolve cerium carbonate in water, then add praseodymium carbonate and neodymium carbonate and stir until a transparent and clear solution is obtained. The molar ratio of cerium ions to praseodymium ions and neodymium ions is 80000:1:1, and the mass ratio of cerium salt to water is 1:200;

[0146] S2 Then add nitric acid and acetic acid in sequence and stir until a transparent and clear solution is obtained. The volume ratio of nitric acid, acetic acid to water is 2:1:200; Add ammonia water and ammonium salt. The mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water to ammonium salt is 1:0.21 to obtain a mixed solution;

[0147] S3 Place the mixed solution in a reaction at 55.0 °C and 20 MPa for 20 hours, adjust the pH to 3.5 to obtain a square cerium oxide composite material.

[0148] To prepare a cerium oxide composite material powder, the following steps are included:

[0149] A1 Place the square cerium oxide composite material prepared in step S3 under high temperature and reduced pressure concentration at 120 °C to make the cerium dioxide concentration reach 5% w / w, and the particle size of the square cerium dioxide composite material particles is 30 - 40 nm;

[0150] A2 Concentrate the product of step A1 at 145 °C until the solid content of the composite material is 95.0% w / w, then centrifuge to obtain a precipitate, and place the precipitate in a high temperature drying at 300 °C for 8 hours, and obtain a square cerium oxide composite material powder after deagglomeration.

[0151] Example 4

[0152] The difference between Example 4 and Example 1 is that in Example 4, the cerium salt is cerium sulfate, the praseodymium salt is praseodymium sulfate, and the neodymium salt is neodymium sulfate.

[0153] Specifically:

[0154] A square cerium oxide composite material, the raw materials of the above-mentioned cerium oxide composite material include the following components:

[0155] Cerium nitrate;

[0156] Praseodymium nitrate;

[0157] Neodymium nitrate;

[0158] Ammonia water;

[0159] Ammonium nitrate;

[0160] Acetic acid;

[0161] Nitric acid;

[0162] Water.

[0163] To prepare the above-mentioned square cerium oxide composite material, the following steps are included:

[0164] S1 Dissolve cerium sulfate in water, then add praseodymium sulfate and neodymium sulfate and stir until a transparent and clear solution is obtained. The molar ratio of cerium ions to praseodymium ions and neodymium ions is 80000:1:1, and the mass ratio of cerium salt to water is 1:200;

[0165] S2 Then add nitric acid and acetic acid in sequence and stir until a transparent and clear solution is obtained. The volume ratio of nitric acid, acetic acid to water is 2:1:200; Add ammonia water and ammonium salt. The mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water to ammonium salt is 1:0.21 to obtain a mixed solution;

[0166] S3 Place the mixed solution under a high pressure of 55.0 °C and 20 MPa for reaction for 20 hours, adjust the pH to 3.5 to obtain a square cerium oxide composite material.

[0167] To prepare a cerium oxide composite material powder, the following steps are included:

[0168] A1 Place the square cerium oxide composite material prepared in step S3 under high temperature and reduced pressure concentration at 120 °C to make the cerium dioxide concentration reach 5% w / w, and the particle size of the square cerium dioxide composite material particles is 30 - 40 nm;

[0169] A2 Concentrate the product of step A1 at 145 °C until the solid content of the composite material is 95.0% w / w, then centrifuge to obtain a precipitate, place the precipitate in a high temperature drying at 300 °C for 8 hours, and obtain a square cerium oxide composite material powder after deagglomeration.

[0170] Example 5

[0171] The difference between Example 5 and Example 1 is that in Example 5, the praseodymium salt added is praseodymium nitrate, and no neodymium salt is added.

[0172] Specifically:

[0173] A square cerium oxide composite material, the raw materials of the above-mentioned cerium oxide composite material include the following components:

[0174] Cerium nitrate;

[0175] Praseodymium nitrate;

[0176] Ammonia water;

[0177] Ammonium nitrate;

[0178] Acetic acid;

[0179] Nitric acid.

[0180] The preparation of the above-mentioned square cerium oxide composite material comprises the following steps:

[0181] S1 Dissolve cerium nitrate in water, then add praseodymium nitrate and stir until a transparent and clear solution is obtained. The molar ratio of cerium ions to praseodymium ions is 4000:1, and the mass ratio of cerium salt to water is 1:200;

[0182] S2 Then add nitric acid and acetic acid in sequence and stir until a transparent and clear solution is obtained. The volume ratio of nitric acid, acetic acid to water is 2:1:200; Add ammonia water and ammonium salt. The mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water to ammonium salt is 1:0.21 to obtain a mixed solution;

[0183] S3 Place the mixed solution in a reaction at 55.0 °C and 20 MPa for 20 hours, and adjust the pH to 3.5 with nitric acid to obtain the square cerium oxide composite material.

[0184] The preparation of the cerium oxide composite material powder comprises the following steps:

[0185] A1 Place the square cerium oxide composite material prepared in step S3 under high temperature and reduced pressure concentration at 120 °C to make the cerium dioxide concentration reach 5% w / w. The particle size of the square cerium dioxide composite material is 30 - 40 nm;

[0186] A2 Concentrate the product of step A1 at 145 °C until the solid content of the composite material is 95.0% w / w, then centrifuge to obtain a precipitate. Place the precipitate in a high temperature drying at 300 °C for 8 hours, and obtain the square cerium oxide composite material powder after deagglomeration.

[0187] Example 6

[0188] The difference between Example 6 and Example 1 is that in Example 5, no praseodymium salt is added, and neodymium salt, neodymium nitrate, is added.

[0189] Specifically:

[0190] A square cerium oxide composite material, the raw materials of the above-mentioned cerium oxide composite material include the following components:

[0191] Cerium nitrate;

[0192] Neodymium nitrate;

[0193] Ammonia water;

[0194] Ammonium nitrate;

[0195] Acetic acid;

[0196] Nitric acid.

[0197] The preparation of the above-mentioned square cerium oxide composite material includes the following steps:

[0198] S1 Dissolve cerium nitrate in water, then add neodymium nitrate and stir until a transparent and clear solution is obtained. The molar ratio of cerium ions to neodymium ions is 4000:1, and the mass ratio of cerium salt to water is 1:200;

[0199] S2 Then add nitric acid and acetic acid in sequence and stir until a transparent and clear solution is obtained. The volume ratio of nitric acid, acetic acid to water is 2:1:200; Add ammonia water and ammonium salt. The mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water to ammonium salt is 1:0.21 to obtain a mixed solution;

[0200] S3 Place the mixed solution in a high-pressure reaction at 55.0 °C for 20 hours, and adjust the pH to 3.5 with nitric acid to obtain a square cerium oxide composite material.

[0201] The preparation of the cerium oxide composite material powder includes the following steps:

[0202] A1 Place the square cerium oxide composite material prepared in step S3 under high-temperature and reduced pressure concentration at 120 °C to make the cerium dioxide concentration reach 5% w / w. The particle size of the square cerium dioxide composite material particles is 30 - 40 nm;

[0203] A2 Concentrate the product of step A1 to a solid content of 95.0% w / w at 145 °C, then centrifuge to obtain a precipitate, and place the precipitate in a high-temperature drying at 300 °C for 8 hours. After deagglomeration, a square cerium oxide composite material powder is obtained.

[0204] Example 7

[0205] A polishing liquid has the following components in parts by weight:

[0206] Abrasive, 1.5 parts;

[0207] Ultra-pure water, 85.0 parts;

[0208] Oxidizing agent, 0.5 part;

[0209] Complexing agent, 1.0 part;

[0210] Corrosion inhibitor, 0.1 part;

[0211] Surfactant, 0.2 part;

[0212] pH regulator, 0.2 part.

[0213] Among them, the abrasive is the cerium oxide composite powder prepared in Example 1;

[0214] The oxidizing agent is potassium permanganate;

[0215] The complexing agent is glutamic acid;

[0216] The corrosion inhibitor is ammonia water;

[0217] The surfactant is polyethylene ether;

[0218] The pH regulator is citrate.

[0219] Example 8

[0220] A method for semiconductor polishing using the polishing liquid of Example 7, comprising the following steps:

[0221] Check the components such as the polishing pad and polishing disc of the CMP equipment to ensure they are clean and functioning properly;

[0222] Fix the silicon wafer to be polished on the polishing disc to ensure it is firm;

[0223] Start the equipment, evenly spray the polishing liquid onto the surface of the polishing pad, and start the polishing process;

[0224] After polishing, thoroughly clean the surface of the silicon wafer with deionized water to remove the residual polishing liquid;

[0225] Dry the silicon wafer with nitrogen to prevent water stains from remaining.

[0226] Comparative Example 1

[0227] The difference between Comparative Example 1 and Example 1 is that in step S1 of Comparative Example 1, the molar ratio of cerium ions to praseodymium ions and neodymium ions is 10:1:1.

[0228] Comparative Example 2

[0229] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the mass ratio of cerium salt to water is 1:30000.

[0230] Comparative Example 3

[0231] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, the mass ratio of cerium salt to water is 1:50.

[0232] Comparative Example 4

[0233] The difference between Comparative Example 4 and Example 1 is that in the raw materials of the cerium oxide composite in Comparative Example 4, praseodymium salt and neodymium salt are not contained.

[0234] Comparative Example 5

[0235] The difference between Comparative Example 5 and Example 1 lies in that: in step S2 of Comparative Example 5, nitric acid is not added. At the same time, the amount of acetic acid used in Comparative Example 5 is adjusted to be equal to the total amount of nitric acid and acetic acid used in Example 1.

[0236] Comparative Example 6

[0237] The difference between Comparative Example 6 and Example 1 lies in that: in step S2 of Comparative Example 6, acetic acid is not added. At the same time, the amount of nitric acid used in Comparative Example 6 is adjusted to be equal to the total amount of nitric acid and acetic acid used in Example 1.

[0238] Comparative Example 7

[0239] The difference between Comparative Example 7 and Example 1 lies in that: in step S2 of Comparative Example 7, acetic acid is added first, and then nitric acid is added.

[0240] Comparative Example 8

[0241] The difference between Comparative Example 8 and Example 1 lies in that: in Comparative Example 8, the volume ratio of nitric acid, acetic acid to water is 2:1:75.

[0242] Comparative Example 9

[0243] The difference between Comparative Example 9 and Example 1 lies in that: in Comparative Example 9, the volume ratio of nitric acid, acetic acid to water is 2:1:300.

[0244] Comparative Example 10

[0245] The difference between Comparative Example 10 and Example 1 lies in that: in step S2 of Comparative Example 10, ammonia water is not added.

[0246] Comparative Example 11

[0247] The difference between Comparative Example 11 and Example 1 lies in that: in step S2 of Comparative Example 11, ammonium salt is not added.

[0248] Comparative Example 12

[0249] The difference between Comparative Example 12 and Example 1 lies in that: in Comparative Example 12, in step S2, the mass ratio of water to ammonia water and ammonium salt is 40:4:2.

[0250] Comparative Example 13

[0251] The difference between Comparative Example 13 and Example 1 lies in that: in Comparative Example 12, in step S2, the mass ratio of water to ammonia water and ammonium salt is 120:4:2.

[0252] Comparative Example 14

[0253] The difference between Comparative Example 14 and Example 1 lies in that: in Comparative Example 14, in step S2, the molar ratio of ammonia water and ammonium salt is 1:0.4.

[0254] Comparative Example 15

[0255] The difference between Comparative Example 15 and Example 1 is that in Comparative Example 15, in step S2, the molar ratio of ammonia water to ammonium salt is 1:0.005.

[0256] Comparative Example 16

[0257] The difference between Comparative Example 16 and Example 1 is that in step S3 of Comparative Example 16, the mixed solution is reacted under high pressure at 15.0 °C for 20 hours.

[0258] Comparative Example 17

[0259] The difference between Comparative Example 17 and Example 1 is that in step S3 of Comparative Example 17, the mixed solution is reacted under high pressure at 170.0 °C for 20 hours.

[0260] Comparative Example 18

[0261] The difference between Comparative Example 18 and Example 1 is that in step S3 of Comparative Example 18, the mixed solution is reacted under high pressure at 55.0 °C for 50 hours.

[0262] Comparative Example 19

[0263] The difference between Comparative Example 19 and Example 1 is that in step S3 of Comparative Example 19, the mixed solution is reacted under high pressure at 55.0 °C for 120 hours.

[0264] Comparative Example 20

[0265] The difference between Comparative Example 20 and Example 1 is that in step S3 of Comparative Example 20, the pH is adjusted to 7.1.

[0266] Comparative Example 21

[0267] The difference between Comparative Example 21 and Example 1 is that in step A1 of Comparative Example 21, the square cerium oxide composite material is placed under high temperature and reduced pressure concentration at 60 °C.

[0268] Comparative Example 22

[0269] The difference between Comparative Example 22 and Example 1 is that in step A1 of Comparative Example 22, the square cerium oxide composite material is placed under high temperature and reduced pressure concentration at 200 °C.

[0270] Comparative Example 23

[0271] The difference between Comparative Example 23 and Example 1 is that in step A2 of Comparative Example 23, the product of step A1 is placed under high pressure concentration at 80 °C.

[0272] Comparative Example 24

[0273] The difference between Comparative Example 24 and Example 1 is that in step A2 of Comparative Example 23, the product of step A1 was placed under high-pressure concentration at 200 °C.

[0274] Comparative Example 25

[0275] The difference between Comparative Example 25 and Example 1 is that in step A2 of Comparative Example 25, the precipitate was placed for high-temperature drying at 280 °C.

[0276] Comparative Example 26

[0277] The difference between Comparative Example 26 and Example 1 is that in step A2 of Comparative Example 26, the precipitate was placed for high-temperature drying at 1200 °C.

[0278] Comparative Example 27

[0279] The difference between Comparative Example 27 and Example 1 is that in step A2 of Comparative Example 27, the precipitate was placed for high-temperature drying at 300 °C for 1.5 hours.

[0280] Comparative Example 28

[0281] The difference between Comparative Example 28 and Example 1 is that in step A2 of Comparative Example 28, the precipitate was placed for high-temperature drying at 300 °C for 12.5 hours.

[0282] Performance test:

[0283] The cerium oxide composite powder prepared in Example 1, Examples 5 - 6 and Comparative Examples 1 - 20 was analyzed, and the analysis results are shown in Table 1.

[0284] Table 1

[0285]

[0286] It can be seen from Table 1 that in Comparative Example 1, since the molar ratio of praseodymium ions and neodymium ions increased beyond the range, the cerium oxide composite particles of the product were not formed.

[0287] In Comparative Example 2, the ratio of cerium salt to water was too low, and the reaction rate was extremely low, resulting in the non-formation of cerium oxide composite particles of the product.

[0288] In Comparative Example 3, the ratio of cerium salt to water was too high, the reaction rate was too fast, and nanoparticles could not be formed.

[0289] In Comparative Example 4, without doping praseodymium and neodymium salts, it affected the hardness of the cerium oxide composite powder when applied in polishing materials, and finally the polishing rate of the CMP polishing solution decreased.

[0290] In Comparative Example 5, nitric acid was not added, and in Comparative Example 6, acetic acid was not added, resulting in the failure of the reaction to proceed smoothly. In Comparative Example 7, changing the addition order of nitric acid and acetic acid led to a decrease in reaction activity, thus causing the reaction to fail to proceed smoothly.

[0291] In Comparative Examples 8-9, the volume ratios of nitric acid, acetic acid to water were inappropriate, resulting in the inability to maintain the shape of the product particles, a decrease in the reaction rate, incomplete reaction, and an increase in impurities in the composite material.

[0292] In Comparative Example 10, ammonia water was not added, resulting in a decrease in reaction efficiency and incomplete reaction.

[0293] In Comparative Example 11, ammonium salt was not added, resulting in incomplete reaction and a change in the morphology of the product particles.

[0294] In Comparative Example 12, the mass ratio of water to ammonia water and ammonium salt was adjusted to 40:4:2, resulting in an overly violent reaction and the product being out of shape.

[0295] In Comparative Example 13, the mass ratio of water to ammonia water and ammonium salt was adjusted to 120:4:2, resulting in an overly slow reaction and the yield dropping below 50%.

[0296] In Comparative Example 14, the molar ratio of ammonia water and ammonium salt was adjusted to 1:0.4, resulting in an increase in impurity content and the product composite material not meeting the requirements for semiconductor applications.

[0297] In Comparative Example 15, the amount of ammonium salt used was too small, resulting in an overly slow reaction, incomplete reaction, and the particles being out of shape.

[0298] In Comparative Example 16, the mixed solution was reacted under high pressure at 15.0 °C. The temperature was too low and the reaction could not start.

[0299] In Comparative Example 17, the mixed solution was reacted under high pressure at 170.0 °C. The temperature was too high, and nano-ceria composite material could not be obtained and could not be formed.

[0300] In Comparative Examples 18-19, adjusting the reaction time would result in the particles being out of shape or waste of materials.

[0301] In Comparative Example 20, adjusting the pH to 7.1 led to a change in the shape of the composite material particles, which were no longer square.

[0302] In addition, in Comparative Example 21, vacuum concentration at a lower temperature was adopted, which could not be achieved.

[0303] In Comparative Example 22, vacuum concentration at too high a temperature was adopted, which had the risk of explosion.

[0304] In Comparative Example 23, the product of Step A1 was concentrated under high pressure at 80 °C, resulting in the concentration not reaching the specified concentration.

[0305] In Comparative Example 24, placing the product of Step A1 under high-pressure concentration at 200°C poses an explosion risk.

[0306] In Comparative Example 25, drying the precipitate at a high temperature of 280°C fails to completely remove the moisture.

[0307] In Comparative Example 26, drying the precipitate at a high temperature of 1200°C causes a change in the shape of the composite material particles.

[0308] In Comparative Example 27, the drying time is too short to achieve complete drying.

[0309] In Comparative Example 28, the drying time is too long, wasting energy resources.

[0310] The above are only embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent transformation made using the content of the specification of the present invention, directly or indirectly applied in related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A method for preparing a square cerium oxide composite material, characterized in that: The following steps are involved: S1: dissolving a mixed cerium salt, a praseodymium salt and / or a neodymium salt in water, sequentially adding an inorganic acid and an organic acid, and then adding ammonia water and an ammonium salt, heating for reaction, and obtaining a mixed solution; S2 adjusting the pH of the mixed solution to be acidic, and performing a sol-gel reaction to obtain the square cerium oxide composite material; In step S1, the temperature of the heating reaction is 30°C-100.0°C; In step S1, the heating reaction is carried out under a high pressure of 20-25 MPa; In step S2, the pH is 3.5-6.5; In step S2, the sol-gel reaction comprises the following steps: distilling and concentrating the mixed solution after adjusting the pH of the mixed solution to be acidic at 30° C. to 160° C.; The inorganic acid is nitric acid, and the organic acid is acetic acid; The volume ratio of the inorganic acid, organic acid and water is 2:1:100-2800; The molar ratio of the ammonia water to the ammonium salt is 1:0.5-0.01; The mass ratio of the cerium salt to water is 1:100-20000; The molar ratio of the cerium ions of the cerium salt to the praseodymium ions of the praseodymium salt is 100-1000000:1; the molar ratio of the cerium ions of the cerium salt to the neodymium ions of the neodymium salt is 100-1000000:

1.

2. The method according to claim 1, characterized in that: In step S2, after the mixed solution undergoes a sol-gel reaction, the method further comprises the following steps: placing the product obtained after the sol-gel reaction at 120° C. - 180° C. and concentrating it to a solid content of ≥ 60.0%, obtaining a precipitate by centrifugation, and drying the precipitate.

3. A square cerium oxide composite material prepared by the method according to any one of claims 1 or 2, characterized in that: The raw materials for preparing the cerium oxide composite material include the following components: Cerium salts; Praseodymium salts and / or neodymium salts; ammonia; Ammonium salts; Organic acids; Inorganic acids; water; The inorganic acid is nitric acid, and the organic acid is acetic acid.

4. The square cerium oxide composite material according to claim 3, characterized in that: The ammonium salt is selected from at least one of ammonium nitrate, ammonium phosphate, ammonium sulfate, ammonium acetate and ammonium chloride.

5. A semiconductor polishing material, characterized in that: The invention comprises a square cerium oxide composite material as claimed in claim 3.

6. A method for polishing a semiconductor, characterized in that: The following steps are involved: The wafer to be polished is fixed on the polishing plate, the polishing equipment is started, the semiconductor polishing material according to claim 5 is prepared into a polishing liquid and then sprayed onto the surface of the polishing pad for polishing.

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