Square cerium oxide composite material as well as preparation method and application thereof

Abstract

The invention discloses a square cerium oxide composite material as well as a preparation method and application thereof. A preparation method of a square cerium oxide composite material comprises the following steps: S1, mixing cerium salt, praseodymium salt and / or neodymium salt in water, sequentially adding inorganic acid and organic acid, then adding ammonia water and ammonium salt, and carrying out a heating reaction to obtain a mixed solution; s2, adjusting the pH value of the mixed solution to be acidic, and performing sol-gel reaction to obtain the square cerium oxide composite material, in the step S1, the temperature of the heating reaction is 30-100.0 DEG C; in the step S1, the heating reaction is performed under the high pressure of 20-25 MPa. The square cerium oxide composite material disclosed by the invention is square and regular, uniform and concentrated in shape, the crystallinity is greater than or equal to 95%, and the purity is greater than or equal to 99.999%.

Description

Technical Field

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

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

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

[0004] Cerium oxide has a wide range of applications, especially in the fields of semiconductor CMP (chemical mechanical planarization), high-end optical polishing, and cosmetics. Cerium oxide is often used in the CMP process in semiconductor manufacturing because of its excellent chemical activity and relatively soft properties. It can polish (planarize) silicon wafers, ILD dielectric layers, STI and other key semiconductor processes at high speeds while having relatively few defects. This property makes cerium oxide an ideal CMP polishing material, especially when making semiconductors below 14 nanometers, it can improve processing efficiency while finely controlling surface quality, thereby improving product reliability and performance.

[0005] Cerium oxide is also widely used in high-end optical polishing. High-end optical polishing requires very high precision and surface quality to ensure the optical performance of the final optical product. The polishing effect of cerium oxide can make the surface of optical glass, optical lenses, laser devices, etc. highly flat, reduce surface defects, and thus improve optical performance. Due to its high optical transparency and low light absorption, cerium oxide has become an indispensable polishing material in the field of high-end optics.

[0006] In the cosmetics field, the application of cerium oxide is mainly reflected in its use as a cosmetic raw material, especially in products such as foundation, moisturizer and sunscreen. Cerium oxide can effectively protect the skin from UV damage due to its good anti-ultraviolet properties. In addition, cerium oxide's low allergy and good skin adaptability also make it 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 cause an oxidation reaction to obtain cerium oxide. The traditional sol-gel method is to dissolve the cerium compound in a solvent, then add appropriate chemical reagents to react to obtain a precursor, and finally obtain cerium oxide powder by drying and roasting. The precipitation method is to add an excess of precipitant to the liquid phase to precipitate the cerium precursor, and then filter it through filter paper, dry it and roast it to obtain cerium oxide.

[0008] However, traditional preparation methods often encounter some challenges when preparing cerium oxide with high crystallinity. First, the cerium oxide obtained by conventional methods has low crystallinity, mainly because during the calcination process at high temperature, the cerium oxide particles tend to grow too rapidly, resulting in low crystallinity. In addition, since a large amount of solvents and chemical reagents may be used 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 ultimately make the obtained cerium oxide low in purity and poor in crystallinity.

[0009] The cerium oxide particles prepared by conventional methods are usually irregular in shape, poorly uniform, and have a rough surface. Especially in the roasting method, the oxidation reaction of cerium under high temperature conditions is often a non-uniform process, resulting in irregular particle shapes. In addition, in the precipitation method and sol-gel method, although the size of the particles can be adjusted by controlling the reaction conditions, due to the fast reaction rate and improper temperature control, irregularly shaped particles are usually obtained. The shape, particle size distribution and surface properties of these particles have a certain influence 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, there is an urgent need to develop a new cerium oxide composite material so that the cerium oxide morphology is square and the shape is regular, uniform and concentrated, with good crystallinity and high purity, which can be widely used in semiconductor CMP polishing, high-end optical polishing, cosmetics and other fields. Summary of the invention

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

[0012] A first aspect of the present invention is: Provided is a method for preparing a square cerium oxide composite material.

[0013] A second aspect of the present invention is: Provided is a square cerium oxide composite material.

[0014] The third aspect of the present invention is: Application of the square cerium oxide composite material.

[0015] The present invention also provides a semiconductor polishing material, which comprises the square cerium oxide composite material.

[0016] The present invention also provides an optical polishing material, which comprises the square cerium oxide composite material.

[0017] The present invention also provides a cosmetic comprising the square cerium oxide composite material.

[0018] Specifically, the technical solution adopted according to the first aspect of the present invention is: S1: mixing cerium salt, praseodymium salt and / or neodymium salt in water, adding inorganic acid and organic acid in sequence, and then adding ammonia water and ammonium salt; 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.

[0019] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects: The method comprises mixing cerium salt, praseodymium salt and / or neodymium salt, sequentially adding inorganic acid and organic acid, adding ammonia water and ammonium salt, so that cerium ions and other metal ions can be effectively coordinated and arranged, promoting the directional growth of crystals, and forming particles with regular square morphology. The method controls the pH to be acidic so as to promote the formation of particles with regular square morphology, make the reaction more controllable, and make the nucleation and growth of crystal grains more uniform. The temperature and pressure of the heating reaction are controlled to ensure that the particle size and impurity content of the product meet the requirements. In addition, the addition of ammonia water also controls the generation rate of cerium oxide, so that the formed nanocrystals have very high regularity. The adjustment of acid and ammonia water also helps to control the agglomeration of particles to form a more uniform composite material.

[0020] In addition, when using the sol-gel method, cerium oxide ions form a nanoscale gel network through a hydrolysis reaction, and the repeated dehydration and hydrolysis during the heating process eventually transform into uniform cerium oxide composite nanoparticles. The sol-gel method can achieve relatively uniform particle growth and smaller grain size, which helps to control the shape and crystallinity of the material; The presence of praseodymium and / or neodymium rare earth metal ions and cerium ions in the cerium oxide unit cell helps stabilize the lattice structure and promote crystal growth, thereby increasing crystallinity. Higher crystallinity helps reduce defects and thus improve the morphology of the material.

[0021] According to one embodiment of the present invention, the method for preparing the square cerium oxide composite material comprises the following steps: mixing cerium salt, praseodymium salt and / or neodymium salt and water in a reaction device, adding inorganic acid, organic acid, ammonia water and ammonium salt, heating the reaction, and obtaining a mixed solution.

[0022] According to one embodiment of the present invention, the method for preparing the square cerium oxide composite material comprises the following steps: cerium salt, praseodymium salt and / or neodymium salt (referred to as CeX, PrX and / or NdX) is first reacted with an organic acid (referred to as HR1) and an inorganic acid (referred to as HR2) to generate R 1 C 2 , R 1 Pr 2 and / or R 1 Nq 2 , then R 1 C 2 , R 1 Pr 2 and / or R 1 Nq 2 With ammonia water, through sol-gel reaction, CeO is generated 2 , PrO 2 and / or NdO 2 , CO 2 , N 2 With H 2 O, of which CeO 2 , PrO 2 and / or NdO 2 That is a square cerium oxide composite material.

[0023] According to one embodiment of the present invention, a method for preparing the square cerium oxide composite material is shown in the schematic diagram as follows: Figure 1 shown.

[0024] According to one embodiment of the present invention, the volume ratio of the inorganic acid, organic acid and water is 2:1:100-2800.

[0025] According to one embodiment of the present invention, the mass ratio of water, ammonia water and ammonium salt is 50-100:4:2.

[0026] According to one 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, the reaction rate will be too high or too low, and ultimately the product will not be formed.

[0027] According to one embodiment of the present invention, in step S2, the sol-gel reaction comprises the following steps: distilling and concentrating the mixed solution at 30° C. to 160° C. In 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 value to be acidic is conducive to promoting uniform precipitation and particle formation.

[0028] According to one embodiment of the present invention, the distillation concentration is high-pressure distillation concentration, and the pressure range is 1-200 MPa, preferably 1-20 MPa, and more preferably 20 MPa.

[0029] According to one embodiment of the present invention, in step S2, after the mixed solution undergoes a sol-gel reaction, the process 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 to obtain the square cerium oxide composite material.

[0030] According to one embodiment of the present invention, the drying of the precipitate comprises the following steps: drying the precipitate at a high temperature of 300° C. to 1100° C. for 2 to 12 hours to obtain a square cerium dioxide composite material.

[0031] According to one embodiment of the present invention, the method for preparing the square cerium oxide composite material further comprises the following steps: after drying the precipitate, performing a deagglomeration operation to obtain nano-square cerium oxide composite material powder.

[0032] According to one 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.

[0033] Specifically, the technical solution adopted according to the second aspect of the present invention is: A square cerium oxide composite material prepared by the method, wherein 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.

[0034] According to the embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects: The square cerium oxide composite material of the present invention is a composite material of cerium oxide, praseodymium oxide and / or neodymium oxide, and has a square morphology with regular, uniform and concentrated shapes. The square cerium oxide composite material has a crystallinity greater than or equal to 95% and a purity greater than or equal to 99.999%.

[0035] According to one embodiment of the present invention, the molar ratio of cerium ion to praseodymium ion of the cerium salt to the praseodymium salt is 100-1000000: 1; the molar ratio of cerium ion to neodymium ion of the cerium salt to the neodymium salt is 100-1000000: 1. When the molar ratio of cerium ion to praseodymium ion or the molar ratio of cerium ion to neodymium ion is not within the above range, the product particles will not be formed and will become irregular products.

[0036] According to one embodiment of the present invention, the molar ratio of cerium ion to praseodymium ion of the cerium salt to the praseodymium salt is 4000-80000:1, preferably 80000:1.

[0037] According to one 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 80000:1.

[0038] According to one 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, but without adding praseodymium salt and / or neodymium salt, the hardness of the product decreases, the impurity content increases, and it can no longer be used in semiconductor polishing materials.

[0039] According to one embodiment of the present invention, the cerium salt comprises Ce 2 (CO 3 ) 3 、Ce(NO 3 ) 3 、 CeCl 3 and Ce 2 (SO 4 ) 3 At least one of .

[0040] According to one embodiment of the present invention, the praseodymium salt comprises Pr 2 (CO 3 ) 3 、Pr(NO 3 ) 3 、PrCl 3 and Pr 2 (SO 4 )3 At least one of .

[0041] According to one embodiment of the present invention, the neodymium salt comprises Nd 2 (CO 3 ) 3 、Nd(NO 3 ) 3 、NdCl 3 and Nd 2 (SO 4 ) 3 At least one of .

[0042] According to one embodiment of the present invention, the purity of the cerium salt, praseodymium salt and neodymium salt is ≥99.999%.

[0043] According to one 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.

[0044] According to one embodiment of the present invention, the organic acid is acetic acid.

[0045] According to one 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.

[0046] According to one embodiment of the present invention, the ammonium salt is ammonium nitrate.

[0047] According to one embodiment of the present invention, the inorganic acid is nitric acid.

[0048] According to one embodiment of the present invention, the concentration of the ammonia water is 1% - 70% w / w.

[0049] According to one embodiment of the present invention, the molar ratio of the ammonia water to the ammonium salt is 1:0.5-0.01.

[0050] Another aspect of the present invention provides a semiconductor polishing material, including the square cerium oxide composite material as described in the first embodiment. Since the application adopts all the technical solutions of the square cerium oxide composite material, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0051] According to one embodiment of the present invention, a method for semiconductor polishing includes the following steps: The wafer to be polished is fixed on the polishing plate, the polishing equipment is started, the semiconductor polishing material is prepared into a polishing liquid and then sprayed onto the surface of the polishing pad for polishing.

[0052] According to one embodiment of the present invention, the polishing liquid has the following components in parts by weight: Abrasive, 1.5-3.0 parts; Ultrapure water, 85.0-90.0 parts; Oxidant, 0.5-1 part; Complexing agent, 1.0-2.0 parts; Corrosion inhibitor, 0.1-0.5 parts; Surfactant, 0.2-0.4 parts; pH adjuster, 0.2-0.3 parts.

[0053] According to one embodiment of the present invention, the abrasive comprises the square cerium oxide composite material as described in the first aspect of the embodiment.

[0054] According to one embodiment of the present invention, the oxidant includes potassium permanganate and / or hydrogen peroxide. The oxidant can promote chemical reactions and accelerate material removal.

[0055] According to one embodiment of the present invention, the complexing agent includes glutamic acid and / or acetylamino acid. The complexing agent can form a complex to stabilize the metal ions in the solution and prevent them from precipitation.

[0056] According to one embodiment of the present invention, the corrosion inhibitor includes ammonia water. The corrosion inhibitor can reduce corrosion of areas that do not require polishing and protect the surface of the material.

[0057] According to one embodiment of the present invention, the surfactant includes polyvinyl ether. The surfactant can reduce surface tension and improve the wettability and dispersibility of the polishing liquid.

[0058] According to one 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.

[0059] Another aspect of the present invention provides an optical polishing material, including the square cerium oxide composite material as described in the first embodiment. Since the application adopts all the technical solutions of the square cerium oxide composite material, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0060] Another aspect of the present invention provides a cosmetic, including the square cerium oxide composite material as described in the first embodiment. Since the application adopts all the technical solutions of the square cerium oxide composite material, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0061] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the process for preparing the square cerium oxide composite material of Example 1.

[0063] Figure 2 This is the SEM image of the cerium oxide composite material powder prepared in Example 1. DETAILED DESCRIPTION

[0064] The words "preferred", "more preferred" and the like in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0065] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0066] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0067] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0068] Example 1 A square cerium oxide composite material, the raw materials of the cerium oxide composite material include the following components: Cerium nitrate; Praseodymium nitrate; Neodymium nitrate; ammonia; Ammonium nitrate; Acetic acid; nitric acid; water.

[0069] The preparation of the square cerium oxide composite material comprises the following steps: 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 ion to praseodymium ion and neodymium ion is 80000:1:1, and the mass ratio of cerium salt to water is 1:200; S2: adding nitric acid and acetic acid in sequence and stirring until a transparent and clear solution is obtained, wherein the volume ratio of nitric acid, acetic acid and water is 2:1:200; adding ammonia water and ammonium salt, wherein the mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water and ammonium salt is 1:0.21, to obtain a mixed solution; S3 The mixed solution was placed at 55.0° C. and 20 MPa high pressure for 20 hours, and the pH was adjusted to 3.5 to obtain a square cerium oxide composite material.

[0070] The preparation of square cerium oxide composite material powder comprises the following steps: A1 The square cerium oxide composite material prepared in step S3 is placed at 120° C. under reduced pressure and concentrated to make the concentration of cerium dioxide reach 5% w / w, and the particle size of the square cerium oxide composite material particles is 30-40 nm; A2: The product of step A1 is concentrated at 145°C to a solid content of 95.0% w / w of the composite material, and then centrifuged to obtain a precipitate. The precipitate is dried at 300°C for 8 hours, and a square cerium oxide composite material powder is obtained after deagglomeration.

[0071] Example 1 Schematic diagram of the process of preparing square cerium oxide composite materials and cerium oxide composite material powders, such as Figure 1 The SEM image of the cerium oxide composite material powder prepared in Example 1 is shown in Figure 2 shown.

[0072] Example 2 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.

[0073] Specific: A square cerium oxide composite material, the raw materials of the cerium oxide composite material include the following components: Cerium chloride; Praseodymium chloride; Neodymium chloride; ammonia; Ammonium nitrate; Acetic acid; nitric acid; water.

[0074] The preparation of the square cerium oxide composite material comprises the following steps: S1 Dissolve cerium chloride in water, then add praseodymium chloride and neodymium chloride and stir until a transparent and clear solution is obtained. The molar ratio of cerium ion to praseodymium ion and neodymium ion is 80000:1:1, and the mass ratio of cerium salt to water is 1:200. S2: adding nitric acid and acetic acid in sequence and stirring until a transparent and clear solution is obtained, wherein the volume ratio of nitric acid, acetic acid and water is 2:1:200; adding ammonia water and ammonium salt, wherein the mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water and ammonium salt is 1:0.21, to obtain a mixed solution; S3 The mixed solution was placed at 55.0° C. and 20 MPa high pressure for 20 hours, and the pH was adjusted to 3.5 to obtain a square cerium oxide composite material.

[0075] The preparation of cerium oxide composite material powder comprises the following steps: A1 The square cerium oxide composite material prepared in step S3 is placed at 120° C. under reduced pressure and concentrated to make the concentration of cerium dioxide reach 5% w / w, and the particle size of the square cerium oxide composite material particles is 30-40 nm; A2: The product of step A1 is concentrated at 145°C to a solid content of 95.0% w / w of the composite material, and then centrifuged to obtain a precipitate. The precipitate is dried at 300°C for 8 hours, and a square cerium oxide composite material powder is obtained after deagglomeration.

[0076] Example 3 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.

[0077] Specific: A square cerium oxide composite material, the raw materials of the cerium oxide composite material include the following components: Cerium carbonate; Praseodymium carbonate; Neodymium carbonate; ammonia; Ammonium nitrate; Acetic acid; nitric acid; water.

[0078] The preparation of the square cerium oxide composite material comprises the following steps: 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 ion to praseodymium ion and neodymium ion is 80000:1:1, and the mass ratio of cerium salt to water is 1:200. S2: adding nitric acid and acetic acid in sequence and stirring until a transparent and clear solution is obtained, wherein the volume ratio of nitric acid, acetic acid and water is 2:1:200; adding ammonia water and ammonium salt, wherein the mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water and ammonium salt is 1:0.21, to obtain a mixed solution; S3 The mixed solution was placed at 55.0° C. and 20 MPa high pressure for 20 hours, and the pH was adjusted to 3.5 to obtain a square cerium oxide composite material.

[0079] The preparation of cerium oxide composite material powder comprises the following steps: A1 The square cerium oxide composite material prepared in step S3 is placed at 120° C. under reduced pressure and concentrated to make the concentration of cerium dioxide reach 5% w / w, and the particle size of the square cerium oxide composite material particles is 30-40 nm; A2: The product of step A1 is concentrated at 145°C to a solid content of 95.0% w / w of the composite material, and then centrifuged to obtain a precipitate. The precipitate is dried at 300°C for 8 hours, and a square cerium oxide composite material powder is obtained after deagglomeration.

[0080] Example 4 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.

[0081] Specific: A square cerium oxide composite material, the raw materials of the cerium oxide composite material include the following components: Cerium nitrate; Praseodymium nitrate; Neodymium nitrate; ammonia; Ammonium nitrate; Acetic acid; nitric acid; water.

[0082] The preparation of the square cerium oxide composite material comprises the following steps: 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 ion to praseodymium ion and neodymium ion is 80000:1:1, and the mass ratio of cerium salt to water is 1:200. S2: adding nitric acid and acetic acid in sequence and stirring until a transparent and clear solution is obtained, wherein the volume ratio of nitric acid, acetic acid and water is 2:1:200; adding ammonia water and ammonium salt, wherein the mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water and ammonium salt is 1:0.21, to obtain a mixed solution; S3 The mixed solution was placed at 55.0° C. and 20 MPa high pressure for 20 hours, and the pH was adjusted to 3.5 to obtain a square cerium oxide composite material.

[0083] The preparation of cerium oxide composite material powder comprises the following steps: A1 The square cerium oxide composite material prepared in step S3 is placed at 120° C. under reduced pressure and concentrated to make the concentration of cerium dioxide reach 5% w / w, and the particle size of the square cerium oxide composite material particles is 30-40 nm; A2: The product of step A1 is concentrated at 145°C to a solid content of 95.0% w / w of the composite material, and then centrifuged to obtain a precipitate. The precipitate is dried at 300°C for 8 hours, and a square cerium oxide composite material powder is obtained after deagglomeration.

[0084] Example 5 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.

[0085] Specific: A square cerium oxide composite material, the raw materials of the cerium oxide composite material include the following components: Cerium nitrate; Praseodymium nitrate; ammonia; Ammonium nitrate; Acetic acid; Nitric acid.

[0086] The preparation of the square cerium oxide composite material comprises the following steps: 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 ion to praseodymium ion is 4000:1, and the mass ratio of cerium salt to water is 1:200; S2: adding nitric acid and acetic acid in sequence and stirring until a transparent and clear solution is obtained, wherein the volume ratio of nitric acid, acetic acid and water is 2:1:200; adding ammonia water and ammonium salt, wherein the mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water and ammonium salt is 1:0.21, to obtain a mixed solution; S3 The mixed solution was placed at 55.0° C. and 20 MPa high pressure for 20 hours, and the pH was adjusted to 3.5 with nitric acid to obtain a square cerium oxide composite material.

[0087] The preparation of cerium oxide composite material powder comprises the following steps: A1 The square cerium oxide composite material prepared in step S3 is placed at 120° C. under reduced pressure and concentrated to make the concentration of cerium dioxide reach 5% w / w, and the particle size of the square cerium oxide composite material particles is 30-40 nm; A2: The product of step A1 is concentrated at 145°C to a solid content of 95.0% w / w of the composite material, and then centrifuged to obtain a precipitate. The precipitate is dried at 300°C for 8 hours, and a square cerium oxide composite material powder is obtained after deagglomeration.

[0088] Example 6 The difference between Example 6 and Example 1 is that: in Example 5, no praseodymium salt is added, and the added neodymium salt is neodymium nitrate.

[0089] Specific: A square cerium oxide composite material, the raw materials of the cerium oxide composite material include the following components: Cerium nitrate; Neodymium nitrate; ammonia; Ammonium nitrate; Acetic acid; Nitric acid.

[0090] The preparation of the square cerium oxide composite material comprises the following steps: 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 ion to neodymium ion is 4000:1, and the mass ratio of cerium salt to water is 1:200. S2: adding nitric acid and acetic acid in sequence and stirring until a transparent and clear solution is obtained, wherein the volume ratio of nitric acid, acetic acid and water is 2:1:200; adding ammonia water and ammonium salt, wherein the mass ratio of water to ammonia water and ammonium salt is 85:4:2, and the molar ratio of ammonia water and ammonium salt is 1:0.21, to obtain a mixed solution; S3 The mixed solution was placed under high pressure at 55.0° C. for 20 hours, and the pH was adjusted to 3.5 with nitric acid to obtain a square cerium oxide composite material.

[0091] The preparation of cerium oxide composite material powder comprises the following steps: A1 The square cerium oxide composite material prepared in step S3 is placed at 120° C. under reduced pressure and concentrated to make the concentration of cerium dioxide reach 5% w / w, and the particle size of the square cerium oxide composite material particles is 30-40 nm; A2: The product of step A1 is concentrated at 145°C to a solid content of 95.0% w / w of the composite material, and then centrifuged to obtain a precipitate. The precipitate is dried at 300°C for 8 hours, and a square cerium oxide composite material powder is obtained after deagglomeration.

[0092] Example 7 A polishing liquid having the following components in parts by weight: Abrasive, 1.5 parts; Ultrapure water, 85.0 parts; Oxidant, 0.5 part; Complexing agent, 1.0 part; Corrosion inhibitor, 0.1 part; Surfactant, 0.2 parts; pH adjuster, 0.2 parts.

[0093] Wherein, the abrasive is the cerium oxide composite material powder prepared in Example 1; The oxidant is potassium permanganate; The complexing agent is glutamic acid; The corrosion inhibitor is ammonia water; The surfactant is polyvinyl ether; The pH adjuster was citrate.

[0094] Example 8 A method for semiconductor polishing using the polishing liquid of Example 7 comprises the following steps: Check the polishing pads, polishing discs and other components of the CMP equipment to ensure they are clean and functioning properly; Fix the silicon wafer to be polished on the polishing plate to ensure it is firm; Start the equipment, spray the polishing liquid evenly onto the surface of the polishing pad, and start the polishing process; After polishing, use deionized water to thoroughly clean the surface of the silicon wafer to remove residual polishing liquid; Use nitrogen to dry the silicon wafer to prevent water stains.

[0095] Comparative Example 1 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.

[0096] Comparative Example 2 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.

[0097] Comparative Example 3 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.

[0098] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the raw materials of the cerium oxide composite material in Comparative Example 4 do not contain praseodymium salt and neodymium salt.

[0099] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that no nitric acid is added in step S2 of Comparative Example 5, and at the same time, the amount of acetic acid in Comparative Example 5 is adjusted to be equal to the total amount of nitric acid and acetic acid in Example 1.

[0100] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that acetic acid is not added in step S2 of Comparative Example 6, and the amount of nitric acid in Comparative Example 6 is adjusted to be equal to the total amount of nitric acid and acetic acid in Example 1.

[0101] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that in step S2 of Comparative Example 7, acetic acid is added first and then nitric acid.

[0102] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that in Comparative Example 8, the volume ratio of nitric acid, acetic acid and water is 2:1:75.

[0103] Comparative Example 9 The difference between Comparative Example 9 and Example 1 is that in Comparative Example 9, the volume ratio of nitric acid, acetic acid and water is 2:1:300.

[0104] Comparative Example 10 The difference between Comparative Example 10 and Example 1 is that in step S2 of Comparative Example 10, no ammonia water is added.

[0105] Comparative Example 11 The difference between Comparative Example 11 and Example 1 is that no ammonium salt is added in step S2 of Comparative Example 11.

[0106] Comparative Example 12 The difference between Comparative Example 12 and Example 1 is that in Comparative Example 12, in step S2, the mass ratio of water to ammonia water and ammonium salt is 40:4:2.

[0107] Comparative Example 13 The difference between Comparative Example 13 and Example 1 is that in Comparative Example 12, in step S2, the mass ratio of water to ammonia water and ammonium salt is 120:4:2.

[0108] Comparative Example 14 The difference between Comparative Example 14 and Example 1 is that in Comparative Example 14, in step S2, the molar ratio of ammonia water to ammonium salt is 1:0.4.

[0109] Comparative Example 15 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.

[0110] Comparative Example 16 The difference between Comparative Example 16 and Example 1 is that in step S3 of Comparative Example 16, the mixed solution is placed under high pressure at 15.0° C. to react for 20 hours.

[0111] Comparative Example 17 The difference between Comparative Example 17 and Example 1 is that in step S3 of Comparative Example 17, the mixed solution is placed under high pressure at 170.0° C. to react for 20 hours.

[0112] Comparative Example 18 The difference between Comparative Example 18 and Example 1 is that in step S3 of Comparative Example 18, the mixed solution is placed under high pressure at 55.0° C. to react for 50 hours.

[0113] Comparative Example 19 The difference between Comparative Example 19 and Example 1 is that in step S3 of Comparative Example 19, the mixed solution is placed under high pressure at 55.0° C. to react for 120 hours.

[0114] Comparative Example 20 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.

[0115] Comparative Example 21 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 concentrated at a high temperature of 60° C. under reduced pressure.

[0116] Comparative Example 22 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 concentrated under reduced pressure at a high temperature of 200°C.

[0117] Comparative Example 23 The difference between Comparative Example 23 and Example 1 is that in step A2 of Comparative Example 23, the product of step A1 is concentrated under high pressure at 80°C.

[0118] Comparative Example 24 The difference between Comparative Example 24 and Example 1 is that in step A2 of Comparative Example 23, the product of step A1 is concentrated under high pressure at 200°C.

[0119] Comparative Example 25 The difference between Comparative Example 25 and Example 1 is that in step A2 of Comparative Example 25, the precipitate is dried at a high temperature of 280°C.

[0120] Comparative Example 26 The difference between Comparative Example 26 and Example 1 is that in step A2 of Comparative Example 26, the precipitate is dried at a high temperature of 1200°C.

[0121] Comparative Example 27 The difference between Comparative Example 27 and Example 1 is that in step A2 of Comparative Example 27, the precipitate is placed at 300° C. for high temperature drying for 1.5 hours.

[0122] Comparative Example 28 The difference between Comparative Example 28 and Example 1 is that in step A2 of Comparative Example 28, the precipitate is placed at 300° C. for high temperature drying for 12.5 hours.

[0123] Performance Test: The cerium oxide composite material powders prepared in Examples 1, 5-6 and Comparative Examples 1-20 were analyzed. The analysis results are shown in Table 1.

[0124] Table 1

[0125] It can be seen from Table 1 that in Comparative Example 1, the molar ratio of praseodymium ions to neodymium ions increased beyond the range, resulting in the formation of the product cerium oxide composite material particles.

[0126] In Comparative Example 2, the ratio of cerium salt to water is too low, and the reaction rate is extremely low, resulting in the formation of the product cerium oxide composite material particles.

[0127] In Comparative Example 3, the ratio of cerium salt to water is too high, the reaction speed is too fast, and nanoparticles cannot be formed.

[0128] In Comparative Example 4, no praseodymium and neodymium salts are added, which affects the hardness of the cerium oxide composite material powder when used as a polishing material, and ultimately the polishing speed of the CMP polishing liquid decreases.

[0129] No nitric acid was added in Comparative Example 5, and no acetic acid was added in Comparative Example 6, resulting in the reaction not being able to proceed smoothly. Changing the order of adding nitric acid and acetic acid in Comparative Example 7 would result in a decrease in the reaction activity, thereby resulting in the reaction not being able to proceed smoothly.

[0130] In Comparative Examples 8-9, the volume ratio of nitric acid, acetic acid and water is not appropriate, which results in that the shape of the product particles cannot be maintained, the reaction rate is reduced and the reaction is incomplete, and the impurities in the composite material increase.

[0131] In Comparative Example 10, no ammonia water was added, which resulted in a decrease in reaction efficiency and an incomplete reaction.

[0132] In Comparative Example 11, no ammonium salt was added, resulting in incomplete reaction and changes in the morphology of the product particles.

[0133] 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 intense reaction and a poorly formed product.

[0134] In Comparative Example 13, the mass ratio of water to ammonia water and ammonium salt was adjusted to 120:4:2, resulting in a slow reaction and a yield drop below 50%.

[0135] 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, making the product composite material not meet the requirements of semiconductor applications.

[0136] In Comparative Example 15, the amount of ammonium salt used was too little, resulting in a slow reaction, an insufficient reaction, and unformed particles.

[0137] In Comparative Example 16, the mixed solution was placed under high pressure at 15.0°C for reaction, but the temperature was too low and the reaction could not start.

[0138] In Comparative Example 17, the mixed solution was placed under high pressure at 170.0° C. for reaction. However, the temperature was too high, and the nano-cerium oxide composite material could not be obtained and could not be formed.

[0139] In Comparative Examples 18-19, adjusting the reaction time will result in unformed particles or waste of material.

[0140] Adjusting the pH to 7.1 in Comparative Example 20 resulted in a change in the shape of the composite material particles, which were no longer square.

[0141] In addition, Comparative Example 21 used reduced pressure concentration at a lower temperature, which could not be achieved.

[0142] Comparative Example 22 uses reduced pressure concentration at an excessively high temperature, which poses a risk of explosion.

[0143] In Comparative Example 23, the product of Step A1 was concentrated under high pressure at 80°C, resulting in less than a specified concentration.

[0144] In Comparative Example 24, the product of Step A1 is concentrated under high pressure at 200° C., which poses a risk of explosion.

[0145] In Comparative Example 25, the precipitate was dried at a high temperature of 280° C., but the moisture could not be completely removed.

[0146] In Comparative Example 26, the precipitate was dried at a high temperature of 1200° C., resulting in a change in the shape of the composite material particles.

[0147] The drying time of Comparative Example 27 was too short and the product could not be completely dried.

[0148] The drying time of Comparative Example 28 is too long, wasting energy resources.

[0149] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also 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: Mix cerium salt, praseodymium salt and / or neodymium salt in water, add inorganic acid and organic acid in sequence, then add ammonia water and ammonium salt, and heat to react to obtain 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.

2. The method according to claim 1, characterized in that: The volume ratio of the inorganic acid, organic acid and water is 2:1:100-2800.

3. The method according to claim 1, characterized in that: In step S2, the sol-gel reaction comprises the following steps: the mixed solution after adjusting the pH of the mixed solution to be acidic is placed at 30°C - 160°C for distillation and concentration.

4. 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.

5. A square cerium oxide composite material prepared by the method according to any one of claims 1 to 4, 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.

6. The square cerium oxide composite material according to claim 5, characterized in that: The molar ratio of cerium ion to praseodymium ion in the cerium salt to praseodymium salt is 100-1000000:1; the molar ratio of cerium ion to neodymium ion in the cerium salt to neodymium salt is 100-1000000:

1.

7. The square cerium oxide composite material according to claim 5, characterized in that: The ammonium salt is selected from at least one of ammonium nitrate, ammonium phosphate, ammonium sulfate, ammonium acetate and ammonium chloride.

8. The square cerium oxide composite material according to claim 5, characterized in that: The molar ratio of the ammonia water to the ammonium salt is 1:0.5-0.

01.

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

10. 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 9 is prepared into a polishing liquid and then sprayed onto the surface of the polishing pad for polishing.

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