Cerium oxide-based polishing powder, preparation method, polishing solution, and use

Abstract

Cerium oxide-based polishing powder, a preparation method, a polishing solution, and a use. The cerium oxide-based polishing powder comprises porous secondary particles assembled from a plurality of primary grains, the primary grain has a pore diameter of 2-30 nm, a pore volume of 0.10-0.50 cm3 / g, and a specific surface area of 10-80 m2 / g, the content of surface trivalent cerium accounts for 10%-40% of a total content of surface cerium. Microstructures of the cerium oxide-based polishing powder of the present invention are porous cerium oxide-based particles assembled by nano-primary particles. The self-assembly structure enables the cerium oxide-based polishing powder to have a high specific surface area while having a high content of surface trivalent cerium, so that a high polishing rate is achieved. The sub-micron particle size improves the dispersion of the polishing powder in a polishing slurry. The porous structure reduces the Young's modulus of the polishing powder, so that the polishing powder is not prone to cracking in a polishing process, the surface accuracy of a polished workpiece is improved, and the service life of the polishing powder is prolonged. Therefore, the cerium oxide-based polishing powder provided by the present invention has both an excellent polishing rate and polishing accuracy, and has a long service life.

Description

Cerium oxide-based polishing powder, preparation method, polishing liquid and application thereof

[0001] Cross-references

[0002] This application is based on the Chinese patent application with application number 202311210359.7 and application date September 19, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present invention relates to the technical field of rare earth functional materials, and in particular to cerium oxide-based polishing powder, a preparation method thereof, a polishing liquid and applications thereof. Background Art

[0004] With the continuous advancement of science and technology, electronic devices are developing in the direction of becoming increasingly miniaturized and sophisticated, and the requirements for chip integration are also increasing. The surface quality of silicon wafers is a key factor in the manufacturing process of high-performance chips. Chemical mechanical polishing has become the main technical means to achieve global nanoscale flatness, and through the synergistic effect of mechanical and chemical, high polishing rate and polishing accuracy are achieved. Cerium oxide-based polishing powder has a high surface area of ​​1000 square meters. 3+ To Ce 4+ Due to its excellent conversion properties, cerium oxide-based polishing powders can form Ce-O-Si bonds with the surface of the workpiece being polished, thus exhibiting extremely high chemical polishing activity on silicon-based materials. Therefore, cerium oxide-based polishing powders are widely used in the chemical mechanical polishing of shallow trench isolation (STI) layers in integrated circuits.

[0005] Factors that affect the performance of polishing powder include particle size, morphology, hardness and surface Ce 3+ Content, etc. Generally, micron-level or submicron-level polishing powder has a fast polishing speed, but there are more scratches on the surface of the workpiece after polishing. Nano-level cerium oxide reduces the scratches on the workpiece surface after polishing, but the polishing rate is slightly reduced. At the same time, due to its increased specific surface area, it is easy to agglomerate and difficult to disperse during the preparation of polishing slurry, resulting in dish-shaped defects during the polishing process. At present, new structures of cerium oxide have attracted widespread attention, such as self-assembled cerium oxide due to its higher specific surface area and Ce 3+ Porous cerium oxide has attracted much attention due to its high content, but it is prone to breakage during polishing, resulting in a short service life and low reuse rate. Porous cerium oxide has a lower Young's modulus than ordinary cerium oxide due to its pore structure, resulting in less stress concentration and better energy absorption and buffering properties. This reduces the probability of self-breakage during polishing, extends the life of the polishing powder, and reduces damage to the workpiece surface, but its polishing rate will decrease.

[0006] Summary of the Invention

[0007] (1) Purpose of the invention

[0008] The purpose of the present invention is to provide a cerium oxide-based polishing powder which has increased surface trivalent cerium content, is not easy to break, is conducive to improving polishing rate and polishing precision, and prolongs service life, as well as a preparation method, a polishing liquid and its application.

[0009] (2) Technical solution

[0010] In order to solve the above problems, the present invention provides a cerium oxide-based polishing powder, which comprises porous secondary particles assembled from a plurality of primary crystal grains, wherein the pore size of the primary crystal grains is 2-30 nm and the pore volume is 0.10-0.50 cm 3 / g, with a specific surface area of ​​10-80m 2 / g, the surface trivalent cerium content accounts for 10%-40% of the total surface cerium content.

[0011] In another aspect of the present invention, preferably, the primary crystal particle pore size is 5-20 nm, and the pore volume is 0.15-0.45 cm 3 / g, with a specific surface area of ​​25-60m 2 / g, the surface trivalent cerium content accounts for 15%-40% of the total surface cerium content.

[0012] In another aspect of the present invention, preferably, the secondary particle morphology of the cerium oxide-based polishing powder includes at least one of rod-shaped, spherical and triangular morphologies.

[0013] In another aspect of the present invention, preferably, the porous secondary particles have a particle size of 50-800 nm.

[0014] In another aspect of the present invention, preferably, the cerium oxide-based polishing powder has the chemical formula Ce 1-x M x O y , wherein 0≤x≤0.4, 1<y≤2.0; the element M in the chemical formula includes at least one of a transition metal, an alkaline earth metal, aluminum, silicon, an alkali metal and a rare earth element except cerium.

[0015] In another aspect of the present invention, preferably, the M includes at least one of lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, thulium, ytterbium, yttrium, zirconium, iron, magnesium, sodium, calcium, and silicon.

[0016] In another aspect of the present invention, preferably, the main crystal structure of the cerium oxide-based polishing powder is a cubic fluorite structure.

[0017] In another aspect of the present invention, preferably, a method for preparing a cerium oxide-based polishing powder is provided, for preparing the cerium oxide-based polishing powder as described above, comprising the following steps:

[0018] S101, mixing a first solution and a second solution in a predetermined proportion and a predetermined mixing mode to obtain a precipitation slurry; the first solution includes a cerium salt and an M salt, and the second solution includes a precipitant, wherein the ratio of the first solution to the second solution is 1:2.5-6.5;

[0019] S201, aging or hydrothermally treating the precipitation slurry for a preset time, and then performing solid-liquid separation to obtain a first solid;

[0020] S301, drying the first solid to obtain a second solid;

[0021] S401, calcining the second solid material under a calcining atmosphere to obtain cerium oxide-based polishing powder.

[0022] In another aspect of the present invention, preferably, the cerium salt and M salt in step S101 include at least one of sulfate, chloride, nitrate, citrate and acetate; and the total concentration of the cerium salt and M salt in the first solution is 0.05 mol / L-1.20 mol / L.

[0023] In another aspect of the present invention, preferably, the precipitant in step S101 includes at least one of sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, ammonia water, hydrazine hydrate, tetramethylammonium hydroxide and urea; and the concentration of the precipitant in the second solution is 0.10 mol / L-6.00 mol / L.

[0024] In another aspect of the present invention, preferably, the preset mixing mode in step S101 includes: a mixing method, a mixing temperature, and a pH value during the mixing process;

[0025] The mixing method includes at least one of high-speed stirring, high-speed ball milling, high-gravity, ultrasonic, microwave oscillation and centrifugal methods;

[0026] The mixing temperature is 5-95°C;

[0027] The pH value of the mixing process is 4.5-10.0.

[0028] In another aspect of the present invention, preferably, the temperature of the aging or hydrothermal treatment in step S201 is 60-230° C., and the time of the aging or hydrothermal treatment is 1-48 hours.

[0029] In another aspect of the present invention, preferably, the drying temperature in step S301 is 50-100° C.; and the drying time is 4-24 hours.

[0030] In another aspect of the present invention, preferably, the calcination temperature in step S401 is 400-1000° C., and the calcination time is 2-10 h.

[0031] In another aspect of the present invention, preferably, the calcination atmosphere in step S401 is an oxidizing atmosphere or a reducing atmosphere; the oxidizing atmosphere includes at least one of oxygen and air; the reducing atmosphere includes at least one of H2, NH3 and CO.

[0032] In another aspect of the present invention, preferably, a polishing liquid comprises the cerium oxide-based polishing powder as described above or the cerium oxide-based polishing powder prepared by the preparation method as described above.

[0033] In another aspect of the present invention, preferably, it also includes a dispersant, a pH regulator and water; wherein the percentage by weight of the cerium oxide-based polishing powder is less than or equal to 20% of the total weight of the polishing liquid; the percentage by weight of the dispersant is less than or equal to 5% of the total weight of the polishing liquid; and the pH range of the polishing liquid is 4-10.

[0034] In another aspect of the present invention, preferably, the dispersant includes at least one of sodium hexametaphosphate, sodium pyrophosphate, ethyl silicate, sodium lauryl sulfate, carboxymethyl cellulose, polyacrylamide and polyethylene glycol.

[0035] In another aspect of the present invention, preferably, the cerium oxide-based polishing powder as described above, the cerium oxide-based polishing powder prepared by the preparation method as described above, or the polishing liquid as described above are used in the fields of flat glass, mobile phone cover glass, optical glass, liquid crystal display glass, glass substrates and integrated circuits.

[0036] (3) Beneficial effects

[0037] The above technical solution of the present invention has the following beneficial technical effects:

[0038] The microstructure of the cerium oxide-based polishing powder of the present invention comprises porous cerium oxide-based particles assembled from nanometer primary particles. This self-assembled structure allows for a high surface trivalent cerium content and a higher specific surface area, facilitating a higher polishing rate. The submicron particle size improves its dispersibility in the polishing slurry. The porous structure reduces its Young's modulus, making it less susceptible to breakage during the polishing process, thereby improving the surface accuracy of the polished workpiece and extending the life of the polishing powder. Therefore, the cerium oxide-based polishing powder provided by the present invention simultaneously exhibits excellent polishing rate and polishing accuracy, and has a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a scanning electron microscope (SEM) image of cerium oxide nanoparticles in Example 1 of the present invention;

[0040] FIG2 is a surface profile of the glass after polishing with cerium oxide nanoparticles in Example 5 of the present invention. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0042] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] In the description of the present invention, it should be noted that the terms "first", "second" and "third" are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0044] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0045] Example 1

[0046] A cerium oxide-based polishing powder, comprising porous secondary particles assembled from a plurality of primary crystal grains, wherein the primary crystal grains have a particle size of 8-80 nm, a pore size of 2-30 nm, and a pore volume of 0.10-0.50 cm 3 / g, with a specific surface area of ​​10-80m 2 / g, the surface trivalent cerium content accounts for 10%-40% of the total surface cerium content. Further, in this embodiment, the primary grain size is 15-50nm, the pore size is 5-20nm, and the pore volume is 0.15-0.45cm 3 / g, with a specific surface area of ​​25-60m 2 / g, the surface trivalent cerium content accounts for 15%-40% of the total surface cerium content; the secondary particle morphology of the cerium oxide-based polishing powder includes at least one of rod-shaped, spherical and triangular morphologies; the particle size of the porous secondary particles is 50-800nm, and further, in this embodiment, the particle size of the porous secondary particles is 100-500nm; the chemical formula of the cerium oxide-based polishing powder is Ce 1-x M x O y, wherein 0≤x≤0.4, 1<y≤2.0; the element M in the chemical formula includes at least one of a transition metal, an alkaline earth metal, aluminum, silicon, an alkali metal and a rare earth element other than cerium; further, in this embodiment, the M includes at least one of lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, thulium, ytterbium, yttrium, zirconium, iron, magnesium, sodium, calcium and silicon; the main crystal structure of the cerium oxide-based polishing powder is a cubic fluorite structure.

[0047] The microstructure of the cerium oxide based polishing powder of this embodiment is porous cerium oxide based particles assembled from nano primary particles. The self-assembled structure makes it have a high surface area Ce 3+ The cerium oxide-based polishing powder has a high content and a higher specific surface area, which is conducive to achieving a higher polishing rate; the submicron particle size improves its dispersibility in the polishing slurry; and the porous structure reduces its Young's modulus, making it less likely to break during the polishing process, improving the surface accuracy of the polished workpiece and extending the life of the polishing powder. Therefore, the cerium oxide-based polishing powder provided by the present invention has excellent polishing rate and polishing accuracy, and has a long service life.

[0048] Example 2

[0049] A method for preparing cerium oxide-based polishing powder, used to prepare the cerium oxide-based polishing powder as described in Example 1, comprising the following steps:

[0050] S101, uniformly mixing a first solution and a second solution in a predetermined mixing mode according to a proportion to obtain a precipitation slurry; the first solution includes a cerium salt and an M salt, and the second solution includes a precipitant; the ratio of the first solution to the second solution is 1:2.5-6.5;

[0051] The cerium salt and the M salt include at least one of sulfate, chloride, nitrate, citrate and acetate; the total concentration of the cerium salt and the M salt in the first solution is 0.05 mol / L-1.20 mol / L. Optionally, in this embodiment, the total concentration of the cerium salt and the M salt in the first solution is 0.10 mol / L-0.60 mol / L;

[0052] The precipitant includes at least one of sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, ammonia water, hydrazine hydrate, tetramethylammonium hydroxide and urea; the concentration of the precipitant in the second solution is 0.10 mol / L-6.00 mol / L. Optionally, in this embodiment, the concentration of the precipitant in the second solution is 0.30 mol / L-4.00 mol / L;

[0053] The preset mixing mode includes: mixing method, mixing temperature and pH value of the mixing process;

[0054] The mixing method includes at least one of high-speed stirring, high-speed ball milling, high-gravity, ultrasonic, microwave oscillation and centrifugal methods;

[0055] The mixing temperature is 5-95°C; further, in this embodiment, the mixing temperature is 40-80°C;

[0056] The pH value of the mixing process is 4.5-10.0. Furthermore, in this embodiment, the pH value of the mixing process is 5.0-8.0;

[0057] S201, aging or hydrothermally treating the precipitated slurry for a preset time, and then performing solid-liquid separation to obtain a first solid; the aging or hydrothermal treatment temperature is 60-230° C., and further, in this embodiment, the aging or hydrothermal treatment temperature is 80-180° C.; the aging or hydrothermal treatment time is 1-48 hours, and further, in this embodiment, the aging or hydrothermal treatment time is 1-24 hours;

[0058] S301, drying the first solid to obtain a second solid, wherein the drying temperature is 50-100° C. and the drying time is 4-24 hours. Furthermore, in this embodiment, the drying time is 8-20 hours;

[0059] S401. Calcinate the second solid material in a calcination atmosphere to obtain cerium oxide-based polishing powder; the calcination temperature is 400-1000°C. Furthermore, in this embodiment, the calcination temperature is 500-900°C. The calcination time is 2-10h. Furthermore, in this embodiment, the calcination time is 2-6h. The calcination atmosphere is an oxidizing atmosphere or a reducing atmosphere. The oxidizing atmosphere includes at least one of oxygen and air; the reducing atmosphere includes at least one of H2, NH3 and CO.

[0060] The present embodiment uses the above preparation method to obtain the porous self-assembled cerium oxide-based polishing powder in Example 1. The mixing process of the soluble cerium salt and the precipitant is accompanied by high-speed shearing. Under the action of shear force, the agglomerated secondary particles are continuously dispersed, which weakens the aggregation and growth process of the primary nanoparticles. By controlling the reaction temperature, pH and other related conditions, the primary nanoparticles are self-assembled into rod-shaped, spherical and triangular morphologies in different directions. By utilizing the morphological inheritance between carbonates and their oxides, porous self-assembled cerium oxide-based polishing powders with different pore sizes and pore volumes are obtained by calcination. Finally, without the use of additives, a porous cerium oxide-based polishing powder formed by self-assembly of primary nanoparticles is obtained by high-speed shearing, controlling pH, temperature and other precipitation and hydrothermal conditions.

[0061] Example 3

[0062] A polishing liquid comprises the cerium oxide-based polishing powder as described in Example 1 or the cerium oxide-based polishing powder prepared by the preparation method of Example 2; further comprising a dispersant, a pH regulator, and water; wherein the percentage by weight of the cerium oxide-based polishing powder is less than or equal to 20% of the total weight of the polishing liquid; the percentage by weight of the dispersant is less than or equal to 5% of the total weight of the polishing liquid; and the pH range of the polishing liquid is 4-10.

[0063] The dispersant includes at least one of sodium hexametaphosphate, sodium pyrophosphate, ethyl silicate, sodium lauryl sulfate, carboxymethyl cellulose, polyacrylamide and polyethylene glycol.

[0064] Example 4

[0065] The application of the cerium oxide-based polishing powder described in Example 1, the cerium oxide-based polishing powder prepared in Example 2, or the polishing liquid described in Example 3 in the fields of flat glass, mobile phone cover glass, optical glass, liquid crystal display glass, glass substrate, and integrated circuit.

[0066] Example 5

[0067] In this embodiment, chloride salts are used, specifically cerium chloride, lanthanum chloride, and praseodymium chloride in chloride salts. 0.6 mol / L cerium chloride, lanthanum chloride, and praseodymium chloride solutions and 1.2 mol / L ammonium bicarbonate solution are mixed in a 65°C water bath at a ratio of 1:2.5 to obtain a precipitation slurry. The pH is adjusted to 6, stirred and mixed evenly at a speed of 400 rpm, and hydroheated at 100°C for 24 hours. The product after hydrothermal treatment is filtered, washed, and dried at 100°C for 12 hours. The dried product is calcined at 600°C in a nitrogen atmosphere and kept warm for 6 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles. The scanning electron microscope image of the powder is shown in Figure 1, and the chemical formula is Ce: 0.6 La 0.2 Pr 0.2 O2.

[0068] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 5 was prepared into a polishing slurry with a mass concentration of 1 wt % using deionized water. 1 wt % of sodium hexametaphosphate was added as a dispersant, and the pH was adjusted to 6.

[0069] Example 6

[0070] In this embodiment, a chloride salt, specifically cerium chloride among chloride salts, is used. 0.6 mol / L cerium chloride solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a ratio of 1:6.5 in a 60°C water bath to obtain a precipitation slurry. The pH is adjusted to 6, the mixture is evenly mixed by ball milling, and hydrothermal treatment is performed at 120°C for 1 hour. The product after hydrothermal treatment is filtered, washed, and dried at 100°C for 12 hours. The dried product is calcined at 800°C in an air atmosphere and kept warm for 4 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula being CeO2.

[0071] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 6 was prepared into a polishing slurry with a mass concentration of 4 wt % using deionized water. 3 wt % of carboxymethyl cellulose was added as a dispersant, and the pH was adjusted to 8.

[0072] Example 7

[0073] In this embodiment, nitrate, specifically cerium nitrate among nitrates, is used. 0.1 mol / L cerium nitrate solution and 0.3 mol / L ammonium carbonate solution are mixed in a ratio of 1:3 in a 45°C water bath to obtain a precipitation slurry. The pH is adjusted to 8, ultrasonically mixed to obtain a uniform precipitate, and hydrothermally heated at 140°C for 12 hours. The product after hydrothermal treatment is filtered, washed, and dried at 80°C for 24 hours. The dried product is calcined at 700°C in an oxygen atmosphere and kept warm for 8 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula being CeO2.

[0074] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 7 was prepared into a polishing slurry with a mass concentration of 8 wt % using deionized water. 2 wt % of sodium pyrophosphate was added as a dispersant, and the pH was adjusted to 10.

[0075] Example 8

[0076] The difference from Example 7 is that after mixing according to a certain stoichiometric ratio to obtain a precipitation slurry, the pH value is adjusted to 10, and finally a rare earth polishing powder with a chemical formula of CeO2 is obtained.

[0077] Example 9

[0078] In this embodiment, sulfate is used, specifically cerium sulfate, lanthanum sulfate, and neodymium sulfate. 0.3 mol / L cerium sulfate, lanthanum sulfate, and neodymium sulfate solutions and 0.9 mol / L sodium bicarbonate solution are mixed in a 45°C water bath in a ratio of 1:4 to obtain a precipitation slurry, the pH is adjusted to 7, ultrasonically mixed evenly, and hydrothermally heated at 160°C for 48 hours. The product after hydrothermal treatment is filtered, washed, and dried at 60°C for 20 hours. The dried product is calcined at 700°C in an air atmosphere and kept warm for 10 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula Ce 0.8 La 0.1 Nd 0.1 O2.

[0079] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 9 was prepared into a polishing slurry with a mass concentration of 16 wt % using deionized water. 4 wt % of sodium lauryl sulfate was added as a dispersant, and the pH was adjusted to 4.

[0080] Example 10

[0081] In this embodiment, acetate is used, specifically cerium acetate and cerium acetate in acetate. 0.1 mol / L cerium acetate, cerium neodymium acetate solution and 0.1 mol / L urea solution are mixed in a 45°C water bath in a ratio of 1:5 to obtain a precipitation slurry, the pH is adjusted to 5, microwave oscillation is used to mix evenly, and hydrothermal treatment is performed at 200°C for 36 hours. The product after hydrothermal treatment is filtered, washed, and dried at 100°C for 4 hours. The dried product is calcined at 600°C in an air atmosphere and kept warm for 10 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula Ce 0.8 Nd 0.2 O2.

[0082] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 10 was prepared into a polishing slurry with a mass concentration of 20 wt % using deionized water, 5 wt % of ethyl silicate was added as a dispersant, and the pH was adjusted to 10.

[0083] Example 11

[0084] The difference from Example 10 is that the dried product is calcined at 500° C. in an air atmosphere and kept warm for 10 hours to finally obtain rare earth polishing powder with a chemical formula of CeO 2 .

[0085] Example 12

[0086] The difference from Example 10 is that the dried product is calcined at 500° C. in an air atmosphere and kept warm for 2 hours to finally obtain rare earth polishing powder with a chemical formula of CeO 2 .

[0087] Example 13

[0088] In this embodiment, citrate, specifically cerium citrate in citrate, is used. 0.6 mol / L cerium citrate solution and 3.6 mol / L potassium hydroxide solution are mixed in a ratio of 1:6 in a 95°C water bath to obtain a precipitated slurry. The pH is adjusted to 4.5, stirred and mixed evenly, and hydrothermally treated at 180°C for 12 hours. The product after hydrothermal treatment is filtered, washed, and dried at 100°C for 16 hours. The dried product is calcined at 1000°C in an air atmosphere and kept warm for 10 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula being CeO2.

[0089] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 13 was prepared into a polishing slurry with a mass concentration of 0.5 wt % using deionized water, 1 wt % of carboxymethyl cellulose was added as a dispersant, and the pH was adjusted to 10.

[0090] Example 14

[0091] The difference from Example 12 is that the dried product is calcined at 400° C. in an air atmosphere and kept warm for 10 hours to finally obtain rare earth polishing powder with a chemical formula of CeO 2 .

[0092] Example 15

[0093] In this embodiment, a chloride salt, specifically cerium chloride, is used. 1.2 mol / L cerium chloride solution and 2.4 mol / L ammonia water are mixed in a ratio of 1:5.5 in a 25°C water bath to obtain a precipitated slurry. The pH is adjusted to 6, the mixture is centrifuged and evenly mixed, and the precipitate is hydrothermally heated at 230°C for 6 hours. The product after hydrothermal treatment is filtered, washed, and dried at 90°C for 12 hours. The dried product is calcined at 900°C in an air atmosphere and kept warm for 8 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula being CeO2.

[0094] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 15 was prepared into a polishing slurry with a mass concentration of 0.1 wt % using deionized water. 0.1 wt % of polyacrylamide was added as a dispersant, and the pH was adjusted to 10.

[0095] Example 16

[0096] The difference from Example 15 is that 1.2 mol / L cerium chloride solution and 2.4 mol / L ammonia water are mixed in a certain stoichiometric ratio in a 95° C. water bath to obtain a precipitation slurry, and finally a rare earth polishing powder with a chemical formula of CeO 2 is obtained.

[0097] Example 17

[0098] In this embodiment, nitrates are used, specifically cerium nitrate, lanthanum nitrate, and praseodymium nitrate. 0.9 mol / L cerium nitrate, lanthanum nitrate, and praseodymium nitrate solutions and 5.0 mol / L ammonia water are mixed in a 65°C water bath at a ratio of 1:4.5 to obtain a precipitation slurry. The pH is adjusted to 10, ultrasonically mixed, and hydrothermally heated at 140°C for 12 hours. The product after hydrothermal treatment is filtered, washed, and dried at 70°C for 12 hours. The dried product is calcined at 700°C in a nitrogen atmosphere and kept warm for 8 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula Ce 0.8 La 0.1 Pr 0.1 O2.

[0099] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 17 was prepared into a polishing slurry with a mass concentration of 12 wt % using deionized water. 5 wt % of polyethylene glycol amine was added as a dispersant, and the pH was adjusted to 10.

[0100] Example 18

[0101] The difference from Example 17 is that 1.2 mol / L cerium nitrate, lanthanum nitrate, praseodymium nitrate solution and 6.0 mol / L ammonia water are mixed in a ratio of 1:4 in a 65°C water bath to obtain a precipitation slurry, and finally a rare earth polishing powder with a chemical formula of CeO2 is obtained.

[0102] Example 19

[0103] In this embodiment, a chloride salt, specifically cerium chloride among chloride salts, is used. A 0.05 mol / L cerium chloride solution and a 0.1 mol / L ammonium bicarbonate solution are mixed in a stoichiometric ratio in a 60°C water bath to obtain a precipitation slurry. The pH is adjusted to 7, mixed uniformly under high gravity, and hydrothermally treated at 120°C for 30 hours. The product after hydrothermal treatment is filtered, washed, and dried at 100°C for 8 hours. The dried product is calcined at 800°C in an ammonia atmosphere and kept warm for 4 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula being CeO2.

[0104] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 19 was prepared into a polishing slurry with a mass concentration of 1 wt % using deionized water. 1 wt % of sodium hexametaphosphate was added as a dispersant, and the pH was adjusted to 10.

[0105] Example 20

[0106] In this embodiment, nitrate, specifically cerium nitrate among nitrates, is used. 0.6 mol / L cerium nitrate solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a ratio of 1:3.4 in a 5°C water bath to obtain a precipitation slurry. The pH is adjusted to 7, ball milled and mixed evenly, and aged at 60°C for 42 hours. The product after hydrothermal treatment is filtered, washed, and dried at 700°C for 16 hours. The dried product is calcined at 800°C in an ammonia atmosphere and kept warm for 4 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula being CeO2.

[0107] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 20 was prepared into a polishing slurry with a mass concentration of 15 wt % using deionized water. 5 wt % of carboxymethyl cellulose was added as a dispersant, and the pH was adjusted to 10.

[0108] Example 21

[0109] The difference from Example 20 is that the mixture is evenly mixed by ball milling and then aged at 80° C. for 42 hours to finally obtain rare earth polishing powder with a chemical formula of CeO 2 .

[0110] Example 22

[0111] The difference from Example 20 is that the mixture is mixed evenly under high gravity and aged at 80° C. for 42 hours to finally obtain rare earth polishing powder with a chemical formula of CeO 2 .

[0112] Example 23

[0113] The difference from Example 20 is that the mixture is mixed evenly under high gravity and aged at 80° C. for 30 hours to finally obtain rare earth polishing powder with a chemical formula of CeO 2 .

[0114] Example 24

[0115] The difference from Example 20 is that the mixture is mixed evenly under high gravity and aged at 80° C. for 18 hours to finally obtain rare earth polishing powder with the chemical formula CeO 2 .

[0116] Example 25

[0117] In this embodiment, chloride salts are used, specifically cerium chloride and lanthanum chloride in chloride salts. 0.6 mol / L cerium chloride, lanthanum chloride solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a 65°C water bath at a ratio of 1:4.8 to obtain a precipitation slurry. The pH is adjusted to 6, stirred and mixed evenly at a speed of 400 rpm, and hydrothermaled at 100°C for 24 hours. The product after hydrothermal treatment is filtered, washed, and dried at 50°C for 8 hours. The dried product is calcined at 900°C in an air atmosphere and kept warm for 6 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula of Ce0.8 La 0.2 O2.

[0118] The cerium-based rare earth polishing powder prepared according to the process parameters of Example 25 was prepared into a polishing slurry with a mass concentration of 1 wt % using deionized water. 1 wt % of sodium hexametaphosphate was added as a dispersant, and the pH was adjusted to 10.

[0119] Example 26

[0120] The difference from Example 25 is that the dried product is calcined at 900°C in a hydrogen atmosphere for 6 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula Ce 0.8 La 0.2 O2.

[0121] Example 27

[0122] The difference from Example 25 is that the dried product is calcined at 900°C in a carbon monoxide atmosphere for 6 hours to obtain a porous cerium oxide-based rare earth polishing powder assembled from primary nanoparticles, with the chemical formula Ce 0.8 La 0.2 O2.

[0123] Example 28

[0124] The difference from Example 6 is that 0.6 mol / L cerium chloride, praseodymium chloride solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a 65°C water bath at a ratio of 1:6 to obtain a precipitate slurry, and finally a chemical formula Ce is obtained. 0.8 Pr 0.2 O2 rare earth polishing powder.

[0125] Example 29

[0126] The difference from Example 6 is that 0.6 mol / L cerium nitrate, zirconium nitrate solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a 65°C water bath at a ratio of 1:4.2 to obtain a precipitate slurry, and finally a chemical formula Ce is obtained. 0.8 Zr 0.2 O2 rare earth polishing powder.

[0127] Example 30

[0128] The difference from Example 6 is that 0.6 mol / L cerium nitrate, zirconium nitrate solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a 65°C water bath at a ratio of 1:5 to obtain a precipitate slurry, and finally a chemical formula Ce is obtained. 0.9 Zr 0.1 O2 rare earth polishing powder.

[0129] Example 31

[0130] The difference from Example 6 is that 0.6 mol / L cerium nitrate, yttrium nitrate, zirconium nitrate solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a ratio of 1:6.2 in a 65°C water bath to obtain a precipitate slurry, and finally a chemical formula Ce is obtained. 0.8 Y 0.1 Zr 0.1 O2 rare earth polishing powder.

[0131] Example 32

[0132] The difference from Example 6 is that 0.6 mol / L cerium nitrate, yttrium nitrate solution and 1.2 mol / L ammonium bicarbonate solution are mixed in a 65°C water bath at a ratio of 1:2.7 to obtain a precipitate slurry, and finally a chemical formula Ce is obtained. 0.9 Y 0.1 O2 rare earth polishing powder.

[0133] The D50 particle size of the rare earth polishing powders obtained in Examples 5 to 32 was measured using a dynamic laser particle size analyzer, the surface trivalent cerium content was measured using X-ray photoelectron spectroscopy, and the specific surface area and pore volume were measured using a nitrogen adsorption-desorption instrument. The morphology, primary particle size, and pore size were measured using a scanning electron microscope.

[0134] The test data and the chemical formula of the rare earth polishing powder are listed in Table 1.

[0135] Table 1 Polishing powder data obtained in Examples 5 to 32

[0136] The microstructure of the cerium oxide-based polishing powder in the above embodiment is porous cerium oxide-based particles assembled from nano primary particles. The self-assembled structure makes it have a high surface area Ce. 3+ The content is high and the specific surface area is higher, which is conducive to obtaining a higher polishing rate.

[0137] Application Examples 5 to 32

[0138] Take the polishing slurries configured in Examples 5 to 32 respectively. Use the prepared rare earth polishing slurry to polish K9 glass (80mm×100mm×0.5mm) or polish silicon oxide wafers (4 inches in diameter), with a polishing pressure of 4.95psi, a polishing disc and a stage rotation speed of 90 and 40rpm / min respectively, a polishing time of 10min, and a polishing slurry flow rate of 50mL / min. The polishing rate was measured, and the surface roughness Sa of the glass before and after polishing was measured by a non-contact surface profiler. The polishing slurry was recycled, and the number of cycles was when its polishing rate was reduced to 80% of the initial polishing rate, and the test results are listed in Table 2. The white light interference image of the K9 glass after polishing in Example 5 is shown in Figure 2, where Sa is the arithmetic mean height of the surface, indicating the surface roughness, Sq is the root mean square height, and Sz is the maximum height.

[0139] Table 2 Polishing data of polishing slurries configured in Examples 5 to 32

[0140] The polishing data of the above embodiments show that the submicron particle size of the polishing powder of the present invention improves its dispersibility in the polishing slurry; the porous structure reduces its Young's modulus, making it less likely to break during the polishing process, thereby improving the surface accuracy of the polished workpiece and extending the life of the polishing powder. Therefore, the cerium oxide-based polishing powder provided by the present invention has both excellent polishing rate and polishing accuracy, and has a longer service life.

[0141] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or illustrative of the principles of the present invention and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents thereof.

[0142] The present invention has been described above with reference to the embodiments thereof. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Those skilled in the art may make various substitutions and modifications without departing from the scope of the present invention, and such substitutions and modifications are intended to fall within the scope of the present invention.

[0143] Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.

[0144] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A cerium oxide-based polishing powder, characterized in that: The cerium oxide-based polishing powder comprises porous secondary particles assembled from a plurality of primary crystal grains, wherein the pore size of the primary crystal grains is 2-30 nm and the pore volume is 0.10-0.50 cm 3 / g, specific surface area of ​​10-80m 2 / g, the surface trivalent cerium content accounts for 10%-40% of the total surface cerium content.

2. The cerium oxide-based polishing powder according to claim 1, characterized in that: The primary crystal particle pore size is 5-20 nm, and the pore volume is 0.15-0.45 cm 3 / g, the surface trivalent cerium content accounts for 15%-40% of the total surface cerium content.

3. The cerium oxide-based polishing powder according to claim 1, characterized in that: The secondary particle morphology of the cerium oxide-based polishing powder includes at least one of rod-shaped, spherical and triangular morphologies.

4. The cerium oxide-based polishing powder according to claim 1, characterized in that: The particle size of the porous secondary particles is 50-800 nm.

5. The cerium oxide-based polishing powder according to claim 1, characterized in that: The chemical formula of the cerium oxide based polishing powder is Ce 1-x M x O y , wherein 0≤x≤0.4, 1<y≤2.0; the element M in the chemical formula includes at least one of transition metals, alkaline earth metals, aluminum, silicon, alkali metals and rare earth elements except cerium.

6. The cerium oxide-based polishing powder according to claim 5, characterized in that: The M includes at least one of lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, thulium, ytterbium, yttrium, zirconium, iron, magnesium, sodium, calcium, and silicon.

7. The cerium oxide-based polishing powder according to claim 1, characterized in that: The main crystal structure of the cerium oxide-based polishing powder is a cubic fluorite structure.

8. A method for preparing cerium oxide-based polishing powder, characterized in that: The method for preparing the cerium oxide-based polishing powder according to any one of claims 1 to 7 comprises the following steps: S101, mixing the first solution and the second solution in a proportion and a preset mixing mode to obtain a precipitation slurry; the first solution includes a cerium salt and an M salt, and the second solution includes a precipitant; wherein the ratio of the first solution to the second solution is 1:2.5-6.5; S201, after aging or hydrothermal treatment of the precipitation slurry for a preset time, solid-liquid separating to obtain a first solid; S301, drying the first solid to obtain a second solid; S401, calcining the second solid material under a calcining atmosphere to obtain cerium oxide-based polishing powder.

9. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The cerium salt and M salt in step S101 include at least one of sulfate, chloride, nitrate, citrate and acetate; the total concentration of the cerium salt and M salt in the first solution is 0.05 mol / L-1.20 mol / L.

10. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The precipitant in step S101 includes at least one of sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, ammonia water, hydrazine hydrate, tetramethylammonium hydroxide and urea; the concentration of the precipitant in the second solution is 0.10 mol / L-6.00 mol / L.

11. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The preset mixing mode in step S101 includes: mixing method, mixing temperature and pH value of the mixing process; The mixing method includes at least one of high-speed stirring method, high-speed ball milling method, ultra-gravity method, ultrasonic method, microwave oscillation method and centrifugal method; The mixing temperature is 5-95°C; The pH value of the mixing process is 4.5-10.

0.

12. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The temperature of the aging or hydrothermal treatment in step S201 is 60-230° C., and the time of the aging or hydrothermal treatment is 1-48 hours.

13. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The drying temperature in step S301 is 50-100° C.; the drying time is 4-24 hours.

14. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The calcination temperature in step S401 is 400-1000° C., and the calcination time is 2-10 hours.

15. The method for preparing the cerium oxide-based polishing powder according to claim 8, characterized in that: The calcination atmosphere in step S401 is an oxidizing atmosphere or a reducing atmosphere; the oxidizing atmosphere includes at least one of oxygen and air; the reducing atmosphere includes at least one of H2, NH3 and CO.

16. A polishing liquid, characterized in that: It comprises the cerium oxide-based polishing powder according to any one of claims 1 to 7 or the cerium oxide-based polishing powder prepared by the preparation method according to claims 8 to 15.

17. The polishing liquid according to claim 16, characterized in that: It also includes a dispersant, a pH regulator and water; wherein the percentage by weight of the cerium oxide-based polishing powder is less than or equal to 20% of the total weight of the polishing liquid; the percentage by weight of the dispersant is less than or equal to 5% of the total weight of the polishing liquid; and the pH range of the polishing liquid is 4-10.

18. The polishing liquid according to claim 16, characterized in that: The dispersant includes at least one of sodium hexametaphosphate, sodium pyrophosphate, ethyl silicate, sodium lauryl sulfate, carboxymethyl cellulose, polyacrylamide and polyethylene glycol.

19. Application of the cerium oxide-based polishing powder according to any one of claims 1 to 7, the cerium oxide-based polishing powder prepared by the preparation method according to claims 8 to 15, or the polishing liquid according to claims 16 to 18 in the fields of flat glass, mobile phone cover glass, optical glass, liquid crystal display glass, glass substrate and integrated circuits.

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