WO2010008124A1 - High purity cerium oxide powder, preparation method thereof, and cmp slurry containing the same - Google Patents
High purity cerium oxide powder, preparation method thereof, and cmp slurry containing the same Download PDFInfo
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- WO2010008124A1 WO2010008124A1 PCT/KR2009/001369 KR2009001369W WO2010008124A1 WO 2010008124 A1 WO2010008124 A1 WO 2010008124A1 KR 2009001369 W KR2009001369 W KR 2009001369W WO 2010008124 A1 WO2010008124 A1 WO 2010008124A1
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- Prior art keywords
- cerium
- cerium oxide
- precipitate
- oxide powder
- high purity
- Prior art date
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- 229910000420 cerium oxide Inorganic materials 0.000 title claims abstract description 78
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 title claims abstract description 78
- 239000000843 powder Substances 0.000 title claims abstract description 56
- 239000002002 slurry Substances 0.000 title claims abstract description 22
- 238000002360 preparation method Methods 0.000 title abstract description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 87
- 239000002244 precipitate Substances 0.000 claims abstract description 67
- 239000012695 Ce precursor Substances 0.000 claims abstract description 26
- 239000006228 supernatant Substances 0.000 claims abstract description 26
- 238000000034 method Methods 0.000 claims abstract description 23
- 239000000203 mixture Substances 0.000 claims abstract description 23
- VYLVYHXQOHJDJL-UHFFFAOYSA-K cerium trichloride Chemical compound Cl[Ce](Cl)Cl VYLVYHXQOHJDJL-UHFFFAOYSA-K 0.000 claims abstract description 21
- KQJQGYQIHVYKTF-UHFFFAOYSA-N cerium(3+);trinitrate;hydrate Chemical compound O.[Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O KQJQGYQIHVYKTF-UHFFFAOYSA-N 0.000 claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000008213 purified water Substances 0.000 claims abstract description 17
- 238000001914 filtration Methods 0.000 claims abstract description 15
- 238000000746 purification Methods 0.000 claims abstract description 15
- 238000005406 washing Methods 0.000 claims abstract description 13
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical class O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000005507 spraying Methods 0.000 claims abstract description 7
- 239000007787 solid Substances 0.000 claims abstract description 5
- 238000006243 chemical reaction Methods 0.000 claims description 36
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 239000002243 precursor Substances 0.000 claims description 9
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 229910017604 nitric acid Inorganic materials 0.000 claims description 6
- 239000007864 aqueous solution Substances 0.000 claims description 5
- 238000010298 pulverizing process Methods 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 3
- 229910004631 Ce(NO3)3.6H2O Inorganic materials 0.000 claims description 2
- 230000001376 precipitating effect Effects 0.000 claims description 2
- 230000002411 adverse Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 6
- 239000012535 impurity Substances 0.000 abstract description 4
- 229910052761 rare earth metal Inorganic materials 0.000 abstract description 4
- 229910052777 Praseodymium Inorganic materials 0.000 abstract description 3
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 abstract 2
- 229910002492 Ce(NO3)3·6H2O Inorganic materials 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 10
- 229910052684 Cerium Inorganic materials 0.000 description 9
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 7
- 238000005498 polishing Methods 0.000 description 7
- 235000012431 wafers Nutrition 0.000 description 7
- 229910052779 Neodymium Inorganic materials 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- 238000004448 titration Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 229910052772 Samarium Inorganic materials 0.000 description 4
- GHLITDDQOMIBFS-UHFFFAOYSA-H cerium(3+);tricarbonate Chemical compound [Ce+3].[Ce+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O GHLITDDQOMIBFS-UHFFFAOYSA-H 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 239000003002 pH adjusting agent Substances 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 239000013049 sediment Substances 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- -1 Raffinate such as La Chemical compound 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000010532 solid phase synthesis reaction Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000008016 vaporization Effects 0.000 description 2
- 150000000703 Cerium Chemical class 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910000175 cerite Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009837 dry grinding Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 238000001238 wet grinding Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1454—Abrasive powders, suspensions and pastes for polishing
- C09K3/1463—Aqueous liquid suspensions
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F17/00—Compounds of rare earth metals
- C01F17/20—Compounds containing only rare earth metals as the metal element
- C01F17/206—Compounds containing only rare earth metals as the metal element oxide or hydroxide being the only anion
- C01F17/224—Oxides or hydroxides of lanthanides
- C01F17/235—Cerium oxides or hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1409—Abrasive particles per se
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K3/00—Materials not provided for elsewhere
- C09K3/14—Anti-slip materials; Abrasives
- C09K3/1454—Abrasive powders, suspensions and pastes for polishing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/30625—With simultaneous mechanical treatment, e.g. mechanico-chemical polishing
Definitions
- the present invention relates to a method of preparing cerium oxide by forming cerium nitrate hydrate, which is an intermediate, in high purity, and more particularly, purified by sodium hydroxide titration and high purity by washing with fine spray of excess purified water. Since cerium nitrate hydrate is used as an intermediate, high purity cerium oxide powder containing little or no Prasedium, which seriously affects the physical properties of various rare earth impurities, especially CMP slurry, a method of preparing the same, and a CMP containing the same It relates to a slurry.
- Cerium oxide powder is a high-performance ceramic powder used as a raw material for abrasives, catalysts, phosphors, and the like, and has recently been widely used as a chemical mechanical abrasive for selective planarization of semiconductor substrates.
- such cerium oxide powder is produced by a gas phase method, a solid phase method and a liquid phase method.
- the gas phase method for preparing cerium oxide powder is a method of directly producing cerium oxide by vaporizing a cerium metal salt precursor and combining it with oxygen, and the like is classified into flame combustion decomposition, gas condensation decomposition, plasma decomposition, and laser vaporization.
- flame combustion decomposition gas condensation decomposition
- plasma decomposition plasma decomposition
- laser vaporization a gas phase method having a problem in that the mass production of cerium oxide is difficult because of the high unit cost and device cost of the cerium metal salt precursor.
- the solid phase method for preparing cerium oxide powder is a method of producing cerium oxide through a calcination process using carbonate, sulfate, oxalate, or the like as a raw material.
- cerium carbonate powder having a large particle size is calcined in an oxygen atmosphere to produce cerium oxide powder having a particle size of 30 to 100 ⁇ m
- the cerium oxide powder Disclosed is a cerium oxide abrasive prepared by dry or wet grinding to control particle size.
- the liquid phase method for preparing cerium oxide powder is a method for directly preparing cerium oxide powder by adding a pH adjusting agent such as ammonia from a trivalent or tetravalent cerium salt starting material, which is classified into precipitation method and hydrothermal synthesis method in detail.
- the unit price and device cost are low, and research and development on this is being actively conducted.
- Korean Laid-Open Patent Publication No. 2007-51680 (name of the invention: cerium carbonate powder, cerium oxide powder, a preparation method thereof, and a CMP slurry containing the same) controls the molar concentration of cerium precursors and carbonate precursors,
- a cerium carbonate powder formed by mixing an additive, a cerium oxide powder formed by heat treatment of the cerium carbonate powder, and a CMP slurry using the cerium oxide powder as an abrasive are disclosed.
- the cerium oxide prepared by using the liquid phase method has a residual raffy since impurities contained in ceraneite, a raw mineral of cerium, such as Raffinate such as La, Ce, Pr, and Nd, which are rare earth elements, remain. Nate adversely affects the physical properties of the cerium oxide powder and the CMP slurry using the cerium oxide powder as an abrasive.
- cerium mineral, especially, Pr has very strong binding power and low solubility, so it is not removed in the process of titrating the cerium oxide raw material by pH adjuster and remains in cerium precursor.
- the remaining Pr is oxidized during the heat treatment of the cerium precursor to be contained in the cerium oxide in a state of being converted into Pr 6 O 11 having a large particle size. Therefore, the particle size distribution of the cerium oxide powder formed by pulverizing cerium oxide containing Pr 6 O 11 is not uniform, which adversely affects physical properties, and when the CMP slurry is prepared using the cerium oxide powder as an abrasive, Scratches occur in the polishing object polished by the CMP slurry (for example, 4 to 15 scratches are generated on the 8-inch wafer, which is the polishing object), thereby deteriorating the quality of electronic products manufactured using the wafer. It has a problem of being connected to.
- an object of the present invention is prepared by using a cerium nitrate hydrate, which is highly purified by purification by titration of sodium hydroxide and washing with water by fine injection of excess purified water, as impurities.
- the present invention provides a high purity cerium oxide powder having a content of prasedium having a serious adverse effect on physical properties of less than 100 ppm, a preparation method thereof, and a CMP slurry containing the same.
- the present invention provides a high purity cerium oxide powder prepared by the method for producing the cerium oxide powder.
- the present invention provides a CMP slurry containing a high purity cerium oxide powder prepared by the method for producing the cerium oxide powder.
- the high purity cerium oxide powder prepared according to the present invention is manufactured by using cerium nitrate hydrate, which is highly purified by washing by titration of sodium hydroxide and washing with fine spraying of excess purified water, as an intermediate, and thus various rare earth elements.
- cerium nitrate hydrate which is highly purified by washing by titration of sodium hydroxide and washing with fine spraying of excess purified water, as an intermediate, and thus various rare earth elements.
- Prasedium which has a serious adverse effect on the physical properties of the CMP slurry, contains little, and has an effect of having a uniform particle size distribution.
- the CMP slurry containing the high purity cerium oxide powder of the present invention hardly scratches the surface of the wafer, which is the main polishing target, the CMP slurry has an effect of ensuring the quality of electronic products using such wafers.
- the method for producing a high-purity cerium oxide powder of the present invention is titrated with sodium hydroxide so that the cerium chloride composition has a pH of 9 to 10, separated into a primary supernatant and a primary precipitate, and filtered to recover the primary precipitate. Steps are included.
- Ceriumite a raw mineral of cerium, is treated with chlorine gas to form a cerium chloride composition, and the cerium chloride composition is adjusted and purified using a pH adjuster to form a cerium precursor, an intermediate of cerium oxide.
- the cerium chloride composition is titrated with sodium hydroxide, which is a pH regulator, to form a reaction system.
- sodium hydroxide which is a pH regulator
- the cerium chloride composition of the reaction system is precipitated to form a primary supernatant and 1. It is divided into secondary sediment.
- sodium hydroxide is temporarily supplied to the cerium chloride composition, exothermic reactions are severely generated in the reaction system.
- the reaction system is controlled with the primary supernatant and the primary by adjusting the exothermic reaction by supplying a small amount of sodium hydroxide to the cerium chloride composition. Separated by sediment.
- the primary supernatant and the primary precipitate are Nd and Sm which are raffinates contained in the cerium chloride composition. While dispersed in the primary supernatant, Nd and Sm hardly remain in the primary precipitate.
- the reaction system in which sodium hydroxide is titrated to the cerium chloride composition is less than pH 9
- the reaction system is not sufficiently classified into the primary supernatant and the primary precipitate, and the acidity of the reaction system in which sodium hydroxide is titrated to the cerium chloride composition is pH. If it exceeds 10, Nd and Sm contained in the cerium chloride composition may not be properly dispersed in the primary supernatant.
- the primary purification step is performed by recovering the primary precipitate in a refined state by greatly reducing Nd and Sm.
- the method for producing a high purity cerium oxide powder of the present invention is to titrate sodium hydroxide so that the acidity of the primary precipitate is pH 10-11, divided into a secondary supernatant and a secondary precipitate and filtered to recover the secondary precipitate.
- a second purification step is included.
- the first precipitate filtered off in the first purification step is titrated with sodium hydroxide to form a reaction system.
- the reaction system is secondary. It is divided into supernatant and secondary precipitate.
- the reaction system is controlled by supplying a small amount of sodium hydroxide to the primary precipitate by adjusting the exothermic reaction and the reaction system with the secondary supernatant and the secondary. Separated by sediment.
- the acidity of the reaction system may be adjusted to pH 10-11.
- Sodium hydroxide should be titrated to distinguish the secondary supernatant from the secondary precipitate.
- the reaction system If the acidity of the reaction system in which sodium hydroxide is titrated to the primary precipitate filtered out in the first purification step is less than pH 10, the reaction system is not sufficiently classified into a secondary supernatant and a secondary precipitate, and sodium hydroxide is added to the primary precipitate.
- the acidity of the reaction system that is titrated exceeds pH 11, La contained in the cerium chloride composition does not disperse properly in the secondary supernatant.
- the secondary purification step is carried out by recovering the secondary precipitate in a state in which La is greatly reduced and purified.
- the method for producing a high purity cerium oxide powder of the present invention includes a washing step of obtaining a solid cerium precursor by fine spraying and filtering purified water to reduce Pr contained in the secondary precipitate.
- Pr contained in the cerium chloride composition is very strong and low solubility in cerium chloride composition so that it remains intact without being removed even in the purification process using a pH adjuster, that is, the first and second purification steps, and a separate Pr If not removed, it remains in the cerium precursor as it is, and the remaining Pr is oxidized during the heat treatment of the cerium precursor and converted into Pr 6 O 11 to be contained in cerium oxide.
- an excess of purified water is added to the recovered secondary precipitate to disperse Pr contained in the secondary precipitate,
- the purified water is finely rinsed with a fine spray shower that can be pulverized and sprayed purified water into fine droplets, and the mixture of the secondary precipitate and purified water is filtered Recover the cerium precursor.
- the method for producing a high purity cerium oxide powder of the present invention includes the step of titrating nitric acid to the cerium precursor to form cerium nitrate hydrate.
- the titration is performed by supplying nitric acid to the cerium precursor in small amounts to form the cerium nitrate hydrate, which is a cerium-inducing substance, by controlling the exothermic reaction.
- the cerium oxide may be formed by applying the liquid phase method to the cerium nitrate hydrate constituted as described above.
- the method for producing a high purity cerium oxide powder of the present invention comprises the step of mixing the cerium nitrate hydrate and the aqueous solution of the carbonic acid precursor and precipitation reaction to separate the tertiary supernatant and the tertiary precipitate and to recover the tertiary precipitate by filtration. do.
- a predetermined amount of a carbonic acid precursor solution such as urea solution is mixed with cerium nitrate hydrate, which is a cerium-derived substance, and left to stand for a predetermined time to induce precipitation reaction.
- the third precipitate is filtered to recover the third precipitate.
- a substitution reaction occurs between the cerium nitrate hydrate and the carbonic acid precursor aqueous solution to form a tertiary precipitate which is cerium oxide.
- the formed tertiary precipitate is characterized in that the raffinate La, Ce, Nd and the like contained in the ceraneite is greatly reduced, and in particular, the content of Pr, which greatly affects the quality as an abrasive, is reduced to less than 100 ppm.
- the method for producing a high purity cerium oxide powder of the present invention includes the step of firing and pulverizing the tertiary precipitate at a constant temperature to form a cerium oxide powder.
- Cerium oxide a tertiary precipitate formed from cerium nitrate hydrate, is heat-treated at 900 to 1000 ° C. to solidify, and the solidified cerium oxide is pulverized to form cerium oxide powder.
- the heat treatment temperature of cerium oxide, the third precipitate is lower than 900 ° C., the cerium oxide is not crystallized properly. If the heat treatment temperature of the cerium oxide, the third precipitate, exceeds 1000 ° C., the cerium oxide particles are strongly bound to form cerium oxide. Dispersibility falls.
- the content of Pr in the cerium oxide which is a tertiary precipitate, is less than 100 ppm
- the content of Pr 6 O 11 which is an oxide produced by the oxidation of Pr in the cerium oxide during the calcination process, is also extremely small. It does not affect the polishing function of the cerium oxide powder formed by grinding.
- the high-purity cerium oxide powder prepared by the above-described method for producing cerium oxide powder is formed from cerium nitrate hydrate having a Pr content of less than 100 ppm, so that the content of Pr 6 O 11 , an oxide of Pr, is extremely small.
- the particle size distribution of the cerium oxide powder is uniform, which can greatly improve the polishing characteristics.
- the high purity cerium oxide powder is mixed with an abrasive to form a CMP slurry.
- This CMP slurry can also greatly improve the polishing rate because the content of Pr 6 O 11 is extremely small, and scratches hardly occur in the polishing object.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The present invention relates to a method for preparing cerium oxide (CeO2) by forming high purity cerium nitrate hydrate (Ce(NO3)3·6H2O) which is an intermediate. More specifically, the method for preparing cerium oxide comprises: recovering precipitates by titrating sodium hydroxide in a cerium chloride composition and separating supernatants and precipitates; obtaining solid cerium precursors by finely spraying and filtering an excess of purified water, wherein the spraying and filtering process is performed to reduce praseodymium (Pr) contained in the precipitates; and obtaining cerium oxide using cerium nitrate hydrate formed by titrating nitric acids in the cerium precursors. In addition, the present invention provides high purity cerium oxide powder, a preparation method thereof, and CMP slurry containing the same. The cerium oxide is prepared using cerium nitrate hydrate as an intermediate, wherein the purity of the cerium nitrate hydrate is increased through purification by titrating sodium hydroxide and washing by finely spraying an excess of purified water, so the high purity cerium oxide powder contains virtually no impurities of various rare-earth elements, especially praseodymium which has an adverse effect on properties of CMP slurry.
Description
본 발명은 중간물질인 세륨나이트레이트 수화물을 고순도로 형성하여 산화세륨을 제조하는 방법에 관한것으로, 보다 상세하게는 수산화나트륨 적정에 의한 정제 및 과량의 정제수의 미세 분사에 의한 수세에 의해 고순도화된 세륨나이트레이트 수화물을 중간물질로 사용하여 제조되므로, 각종 희토류 원소인 불순물 특히 CMP 슬러리의 물성에 심각한 악영향을 미치는 프라세오디움이 거의 함유되지 않는 고순도의 산화세륨 분말, 그 제조방법 및 이를 포함하는 CMP 슬러리에 관한 것이다.The present invention relates to a method of preparing cerium oxide by forming cerium nitrate hydrate, which is an intermediate, in high purity, and more particularly, purified by sodium hydroxide titration and high purity by washing with fine spray of excess purified water. Since cerium nitrate hydrate is used as an intermediate, high purity cerium oxide powder containing little or no Prasedium, which seriously affects the physical properties of various rare earth impurities, especially CMP slurry, a method of preparing the same, and a CMP containing the same It relates to a slurry.
산화세륨 분말은 연마재, 촉매, 형광체 등의 원료로 사용되는 고기능 세라믹 분말로서, 최근에는 반도체 기판의 선택적 평탄화를 위한 화학기계적 연마재로서 널리 사용되고 있다. 일반적으로 이러한 산화세륨 분말은 기상법, 고상법 및 액상법으로 제조되고 있다.Cerium oxide powder is a high-performance ceramic powder used as a raw material for abrasives, catalysts, phosphors, and the like, and has recently been widely used as a chemical mechanical abrasive for selective planarization of semiconductor substrates. In general, such cerium oxide powder is produced by a gas phase method, a solid phase method and a liquid phase method.
산화세륨 분말을 제조하기 위한 기상법은 세륨 금속염 전구체를 기화하고, 산소 등과 결합시켜서 직접 산화세륨을 제조하는 방법으로서, 세부적으로 화염연소 분해법, 기체응축 분해법, 플라즈마 분해법, 레이저 기화법 등으로 구분된다. 그러나, 이러한 기상법은 세륨 금속염 전구체의 단가 및 장치비용이 고가이므로 산화세륨의 대량생산이 곤란하다는 문제점이 있다.The gas phase method for preparing cerium oxide powder is a method of directly producing cerium oxide by vaporizing a cerium metal salt precursor and combining it with oxygen, and the like is classified into flame combustion decomposition, gas condensation decomposition, plasma decomposition, and laser vaporization. However, such a gas phase method has a problem in that the mass production of cerium oxide is difficult because of the high unit cost and device cost of the cerium metal salt precursor.
산화세륨 분말을 제조하기 위한 고상법은 탄산염, 황산염, 옥살산염 등을 원료물질로 하여 소성 공정을 거쳐서 산화세륨을 제조하는 방법이다. 예를 들면, 국제공개특허 WO 1998-14987호 및 WO 1999-31195호에서는 입자 크기가 큰 탄산세륨 분말을 산소 분위기에서 소성하여 입경 30∼100 ㎛의 산화세륨 분말을 제조하고, 상기 산화세륨 분말을 건식 분쇄 또는 습식 분쇄하여 입도를 조절하여 이루어지는 산화세륨 연마재가 개시되어 있다. The solid phase method for preparing cerium oxide powder is a method of producing cerium oxide through a calcination process using carbonate, sulfate, oxalate, or the like as a raw material. For example, in WO 1998-14987 and WO 1999-31195, cerium carbonate powder having a large particle size is calcined in an oxygen atmosphere to produce cerium oxide powder having a particle size of 30 to 100 µm, and the cerium oxide powder Disclosed is a cerium oxide abrasive prepared by dry or wet grinding to control particle size.
그러나, 산화세륨 분말의 분쇄 공정 후에도 입경이 큰 산화세륨 분말이 잔존하여 입도 조절이 곤란하며, 이로 인하여 최종 CMP 슬러리를 제조한 후에도 필터를 이용한 장시간의 여과 공정을 실시해야 하는 문제점이 있다. 산화세륨 분말을 제조하기 위한 액상법은 3가 또는 4가의 세륨염 출발물질로부터 암모니아 등의 pH 조절제를 첨가하여 산화세륨 분말을 직접 제조하는 방법으로서, 세부적으로 침전법, 수열합성법 등으로 구분되며, 원료 단가와 장치비용이 저렴하여, 이에 대한 연구개발이 활발하게 진행되고 있다.However, even after the cerium oxide powder is pulverized, the cerium oxide powder having a large particle size remains, so that it is difficult to control the particle size. Therefore, there is a problem that a long filtration process using a filter must be performed even after the final CMP slurry is prepared. The liquid phase method for preparing cerium oxide powder is a method for directly preparing cerium oxide powder by adding a pH adjusting agent such as ammonia from a trivalent or tetravalent cerium salt starting material, which is classified into precipitation method and hydrothermal synthesis method in detail. The unit price and device cost are low, and research and development on this is being actively conducted.
예를 들면 한국 공개특허공보 제2007-51680호(발명의 명칭 : 탄산세륨 분말, 산화세륨 분말, 그 제조 방법 및 이를 포함하는 CMP 슬러리)에서는 세륨 전구체와 탄산 전구체의 몰 농도를 조절하고 1종 이상의 첨가제를 혼합하여 구성되는 탄산세륨 분말, 상기 탄산세륨 분말을 열처리하여 구성되는 산화세륨 분말, 및 상기 산화세륨 분말을 연마재로 사용하는 CMP 슬러리가 개시되어 있다. For example, Korean Laid-Open Patent Publication No. 2007-51680 (name of the invention: cerium carbonate powder, cerium oxide powder, a preparation method thereof, and a CMP slurry containing the same) controls the molar concentration of cerium precursors and carbonate precursors, A cerium carbonate powder formed by mixing an additive, a cerium oxide powder formed by heat treatment of the cerium carbonate powder, and a CMP slurry using the cerium oxide powder as an abrasive are disclosed.
그러나, 이러한 액상법을 사용하여 제조되는 산화세륨은 세륨의 원료광물인 세라나이트에 함유된 불순물, 즉 희토류 원소인 La, Ce, Pr, Nd 등의 라피네이트(Raffinate)가 잔존하게 되므로, 잔존한 라피네이트가 산화세륨 분말, 및 상기 산화세륨 분말을 연마재로 사용하는 CMP 슬러리의 물성에 악영향을 미치게 된다. 세륨의 원료광물인 세라나이트에 함유된 각종 라피네이트 중에서도, 특히 Pr은 세륨과의 결합력이 매우 강력하고 용해성도 낮아서 산화세륨의 원료물질을 pH 조절제에 의해 적정하는 과정에서도 제거되지 않고 세륨 전구체에 그대로 잔존하게 되며, 상기 잔존된 Pr이 세륨 전구체의 열처리 과정에서 산화되어 입경이 큰 Pr6O11로 변환된 상태로 산화세륨에 함유하게 된다. 따라서 Pr6O11가 함유된 산화세륨을 분쇄하여 형성된 산화세륨 분말의 입도 분포가 균일하지 못하여 물성에 악영향을 미칠 뿐만 아니라, 이러한 산화세륨 분말을 연마재로 사용하여 CMP 슬러리를 제조하는 경우에는, 상기 CMP 슬러리에 의해 연마되는 연마 대상물에서 스크래치가 다발(예를 들면, 연마 대상물인 8인치 웨이퍼에서 4∼15 개의 스크래치가 발생함)하게 되며, 이로 인하여 상기 웨이퍼를 사용하여 제조되는 전자제품의 품질 저하로까지 연결된다는 문제점을 지니고 있다.However, the cerium oxide prepared by using the liquid phase method has a residual raffy since impurities contained in ceraneite, a raw mineral of cerium, such as Raffinate such as La, Ce, Pr, and Nd, which are rare earth elements, remain. Nate adversely affects the physical properties of the cerium oxide powder and the CMP slurry using the cerium oxide powder as an abrasive. Among various raffinates contained in cerite, cerium mineral, especially, Pr has very strong binding power and low solubility, so it is not removed in the process of titrating the cerium oxide raw material by pH adjuster and remains in cerium precursor. The remaining Pr is oxidized during the heat treatment of the cerium precursor to be contained in the cerium oxide in a state of being converted into Pr 6 O 11 having a large particle size. Therefore, the particle size distribution of the cerium oxide powder formed by pulverizing cerium oxide containing Pr 6 O 11 is not uniform, which adversely affects physical properties, and when the CMP slurry is prepared using the cerium oxide powder as an abrasive, Scratches occur in the polishing object polished by the CMP slurry (for example, 4 to 15 scratches are generated on the 8-inch wafer, which is the polishing object), thereby deteriorating the quality of electronic products manufactured using the wafer. It has a problem of being connected to.
따라서, 본 발명의 목적은 수산화나트륨 적정에 의한 정제 및 과량의 정제수의 미세 분사에 의한 수세에 의해 고순도화된 세륨 나이트레이트 수화물을 중간물질로 사용하여 제조되므로, 각종 희토류 원소인 불순물 특히 CMP 슬러리의 물성에 심각한 악영향을 미치는 프라세오디움의 함량이 100 ppm 미만인 고순도의 산화세륨 분말, 그 제조 방법 및 이를 포함하는 CMP 슬러리를 제공하는데 있다.Therefore, an object of the present invention is prepared by using a cerium nitrate hydrate, which is highly purified by purification by titration of sodium hydroxide and washing with water by fine injection of excess purified water, as impurities. The present invention provides a high purity cerium oxide powder having a content of prasedium having a serious adverse effect on physical properties of less than 100 ppm, a preparation method thereof, and a CMP slurry containing the same.
상기와 같은 과제를 해결하기 위하여, 본 발명에서는 세륨 클로라이드 조성물이 pH 9∼10이 되도록 수산화나트륨을 적정하여 1차 상등액과 1차 침전물로 구분하고 여과하여 상기 1차 침전물을 회수하는 1차 정제 단계; 상기 1차 침전물의 산도가 pH 10∼11이 되도록 수산화나트륨을 적정하여 2차 상등액과 2차 침전물로 구분하고 여과하여 상기 2차 침전물을 회수하는 2차 정제 단계; 상기 2차 침전물에 함유된 프라세오디움(Pr)을 저감하도록 정제수를 미세 분사하고 여과하여 Pr 함량이 100 ppm 미만인 고상의 세륨 전구체를 수득하는 수세 단계; 상기 세륨 전구체에 질산을 적정하여 세륨나이트레이트 수화물(Ce(NO3)3·6H2O)을 형성하는 단계; 상기 세륨나이트레이트 수화물과 탄산 전구체 수용액을 혼합하고 침전 반응하여 3차 상등액과 3차 침전물로 구분하고 여과하여 상기 3차 침전물을 회수하는 단계; 및 상기 3차 침전물을 900∼1000 ℃로 소성하고 분쇄하여 산화세륨 분말을 형성하는 단계를 포함하는 고순도 산화세륨 분말의 제조 방법이 제공된다.In order to solve the above problems, in the present invention, the first purification step of recovering the primary precipitate by titrating sodium hydroxide so that the cerium chloride composition has a pH of 9 to 10 by separating the primary supernatant and the primary precipitate and filtering. ; A second purification step of titrating sodium hydroxide so that the acidity of the primary precipitate is pH 10-11, divided into a secondary supernatant and a secondary precipitate, and filtering to recover the secondary precipitate; A water washing step of finely spraying purified water and filtering to reduce prasedium (Pr) contained in the secondary precipitate to obtain a solid cerium precursor having a Pr content of less than 100 ppm; Titrating nitric acid on the cerium precursor to form cerium nitrate hydrate (Ce (NO 3 ) 3 .6H 2 O); Mixing the cerium nitrate hydrate and an aqueous solution of a carbonic acid precursor and precipitating the reaction to separate the tertiary supernatant and the tertiary precipitate and recover the tertiary precipitate by filtration; And firing and pulverizing the tertiary precipitate at 900 to 1000 ° C. to form a cerium oxide powder.
또한, 본 발명에서는 상기 산화세륨 분말의 제조 방법에 의하여 제조되는 고순도 산화세륨 분말이 제공된다.In addition, the present invention provides a high purity cerium oxide powder prepared by the method for producing the cerium oxide powder.
또한, 본 발명에서는 상기 산화세륨 분말의 제조 방법에 의하여 제조되는 고순도 산화세륨 분말을 포함하는 CMP 슬러리가 제공된다.In addition, the present invention provides a CMP slurry containing a high purity cerium oxide powder prepared by the method for producing the cerium oxide powder.
본 발명에 의하여 제조되는 고순도 산화세륨 분말은 수산화나트륨 적정에 의한 정제 및 과량의 정제수의 미세분사에 의한 수세에 의해 고순도화된 세륨 나이트레이트 수화물을 중간물질로 사용하여 제조되므로, 각종 희토류 원소인 불순물 특히 CMP 슬러리의 물성에 심각한 악영향을 미치는 프라세오디움이 거의 함유되지 않고, 균일한 입도 분포를 지니게 되는 효과를 지니고 있다. The high purity cerium oxide powder prepared according to the present invention is manufactured by using cerium nitrate hydrate, which is highly purified by washing by titration of sodium hydroxide and washing with fine spraying of excess purified water, as an intermediate, and thus various rare earth elements. In particular, Prasedium, which has a serious adverse effect on the physical properties of the CMP slurry, contains little, and has an effect of having a uniform particle size distribution.
또한, 본 발명의 고순도 산화세륨 분말을 포함하는 CMP 슬러리는 주 연마 대상물인 웨이퍼의 표면에 스크래치를 거의 발생시키지 않기 때문에, 이러한 웨이퍼를 사용하는 전자제품의 품질을 보장하는 효과를 지니고 있다.In addition, since the CMP slurry containing the high purity cerium oxide powder of the present invention hardly scratches the surface of the wafer, which is the main polishing target, the CMP slurry has an effect of ensuring the quality of electronic products using such wafers.
본 발명에 의한 고순도 산화세륨 분말의 제조 방법에 대하여 실시예를 참조하여 상세하게 설명한다.The manufacturing method of the high purity cerium oxide powder which concerns on this invention is demonstrated in detail with reference to an Example.
우선, 본 발명의 고순도 산화세륨 분말의 제조방법은 세륨클로라이드 조성물이 pH 9∼10이 되도록 수산화나트륨을 적정하여 1차 상등액과 1차 침전물로 구분하고 여과하여 상기 1차 침전물을 회수하는 1차 정제 단계가 포함된다.First, the method for producing a high-purity cerium oxide powder of the present invention is titrated with sodium hydroxide so that the cerium chloride composition has a pH of 9 to 10, separated into a primary supernatant and a primary precipitate, and filtered to recover the primary precipitate. Steps are included.
세륨의 원료광물인 세라나이트를 염소가스로 처리하여 세륨 클로라이드 조성물을 형성하고, 상기 세륨 클로라이드 조성물을 pH 조절제를 사용하여 산도를 조절하고 정제하므로써, 산화세륨의 중간물질인 세륨 전구체를 형성한다.Ceriumite, a raw mineral of cerium, is treated with chlorine gas to form a cerium chloride composition, and the cerium chloride composition is adjusted and purified using a pH adjuster to form a cerium precursor, an intermediate of cerium oxide.
구체적으로, 세륨 클로라이드 조성물을 pH 조절제인 수산화나트륨으로 적정하여 반응계를 형성하되, 상기 반응계의 산도가 pH 9∼10이 되도록 수산화나트륨을 적정하면 상기 반응계의 세륨 클로라이드 조성물이 침전되어 1차 상등액과 1차 침전물로 구분된다. 그런데 세륨 클로라이드 조성물에 수산화나트륨을 일시에 공급하게 되면 반응계에서 발열 반응이 심하게 발생하므로, 세륨클로라이드 조성물에 수산화나트륨을 소량씩 공급하는 적정을 실시하여 발열 반응을 조절하면서 반응계를 1차 상등액과 1차 침전물로 구분시킨다. 상기와 같은 수산화나트륨의 적정에 의해 산도가 pH 9∼10으로 조절된 반응계에서 세륨 클로라이드 조성물이 침전되어 1차 상등액과 1차 침전물로 구분되면, 상기 세륨 클로라이드 조성물에 함유된 라피네이트인 Nd, Sm이 상기 1차 상등액으로 분산하게 되는 반면, 1차 침전물에는 Nd, Sm이 거의 잔류하지 않게 된다.Specifically, the cerium chloride composition is titrated with sodium hydroxide, which is a pH regulator, to form a reaction system. When sodium hydroxide is titrated so that the acidity of the reaction system is pH 9 to 10, the cerium chloride composition of the reaction system is precipitated to form a primary supernatant and 1. It is divided into secondary sediment. However, when sodium hydroxide is temporarily supplied to the cerium chloride composition, exothermic reactions are severely generated in the reaction system. Thus, the reaction system is controlled with the primary supernatant and the primary by adjusting the exothermic reaction by supplying a small amount of sodium hydroxide to the cerium chloride composition. Separated by sediment. When the cerium chloride composition precipitates in the reaction system in which the acidity is adjusted to pH 9-10 by titration of sodium hydroxide as described above, the primary supernatant and the primary precipitate are Nd and Sm which are raffinates contained in the cerium chloride composition. While dispersed in the primary supernatant, Nd and Sm hardly remain in the primary precipitate.
반응계를 형성하기 위하여 세륨 클로라이드 조성물에 적정되는 수산화나트륨의 농도 제한은 없으나, 고순도 산화세륨 분말을 제공하는 본 발명의 목적을 달성하기 위해서는, 상기 반응계의 산도가 pH 9∼10이 되도록 세륨 클로라이드 조성물에 수산화나트륨을 적정하여 1차 상등액과 1차 침전물로 구분해야 한다.There is no concentration limit of sodium hydroxide titrated to the cerium chloride composition to form a reaction system, but in order to achieve the object of the present invention to provide a high purity cerium oxide powder, the acidity of the reaction system may be adjusted to pH 9-10. Sodium hydroxide should be titrated to distinguish the primary supernatant from the primary precipitate.
세륨 클로라이드 조성물에 수산화나트륨이 적정되어 이루어지는 반응계의 산도가 pH 9 미만이면 상기 반응계가 1차 상등액과 1차 침전물로 충분하게 구분되지 않으며, 세륨클로라이드 조성물에 수산화나트륨이 적정되어 이루어지는 반응계의 산도가 pH 10을 초과하면 상기 세륨클로라이드 조성물에 함유된 Nd, Sm이 1차 상등액에 제대로 분산되지 않는다.If the acidity of the reaction system in which sodium hydroxide is titrated to the cerium chloride composition is less than pH 9, the reaction system is not sufficiently classified into the primary supernatant and the primary precipitate, and the acidity of the reaction system in which sodium hydroxide is titrated to the cerium chloride composition is pH. If it exceeds 10, Nd and Sm contained in the cerium chloride composition may not be properly dispersed in the primary supernatant.
상기와 같이 1차 상등액과 1차 침전물로 구분된 반응계를 여과하여, Nd, Sm이 대폭 저감되어 정제된 상태인 1차 침전물을 회수하므로써 1차 정제 단계가 실시된다.As described above, by filtering the reaction system divided into the primary supernatant and the primary precipitate, the primary purification step is performed by recovering the primary precipitate in a refined state by greatly reducing Nd and Sm.
또한, 본 발명의 고순도 산화세륨 분말의 제조 방법은 상기 1차 침전물의 산도가 pH 10∼11이 되도록 수산화나트륨을 적정하여 2차 상등액과 2차 침전물로 구분하고 여과하여 상기 2차 침전물을 회수하는 2차 정제 단계가 포함된다.In addition, the method for producing a high purity cerium oxide powder of the present invention is to titrate sodium hydroxide so that the acidity of the primary precipitate is pH 10-11, divided into a secondary supernatant and a secondary precipitate and filtered to recover the secondary precipitate. A second purification step is included.
1차 정제 단계에서 여과 회수된 1차 침전물을 수산화나트륨으로 적정하여 반응계를 형성하되, 상기 1차 정제 단계와 마찬가지로 상기 반응계의 산도가 pH 10∼11이 되도록 수산화나트륨을 적정하면 상기 반응계가 2차 상등액과 2차 침전물로 구분된다. 그런데 1차 침전물에 수산화나트륨을 일시에 공급하게 되면 반응계에서 발열 반응이 심하게 발생하므로, 1차 침전물에 수산화나트륨을 소량씩 공급하는 적정을 실시하여 발열 반응을 조절하면서 반응계를 2차 상등액과 2차 침전물로 구분시킨다. 상기와 같은 수산화나트륨의 적정에 의해 산도가 pH 10∼11로 조절된 반응계의 침전 현상으로 2차 상등액과 2차 침전물로 구분되면, 세륨클로라이드 조성물에 함유된 라피네이트인 La이 상기 2차 상등액으로 분산하게 되는 반면, 2차 침전물에는 La이 거의 잔류하지 않게 된다.The first precipitate filtered off in the first purification step is titrated with sodium hydroxide to form a reaction system. Likewise in the first purification step, when sodium hydroxide is titrated so that the acidity of the reaction system is pH 10-11, the reaction system is secondary. It is divided into supernatant and secondary precipitate. However, when sodium hydroxide is temporarily supplied to the primary precipitate, exothermic reactions are severely generated in the reaction system. Thus, the reaction system is controlled by supplying a small amount of sodium hydroxide to the primary precipitate by adjusting the exothermic reaction and the reaction system with the secondary supernatant and the secondary. Separated by sediment. When the acidity is adjusted to pH 10-11 by titration of sodium hydroxide as described above, and the secondary supernatant and the secondary precipitate are separated, the raffinate La contained in the cerium chloride composition is converted into the secondary supernatant. On the other hand, little La remains in the secondary precipitate.
반응계를 형성하기 위하여 세륨클로라이드 조성물에 적정되는 수산화나트륨의 농도 제한은 없으나, 고순도 산화세륨 분말을 제공하는 본 발명의 목적을 달성하기 위해서는, 상기 반응계의 산도가 pH 10∼11이 되도록 1차 침전물에 수산화나트륨을 적정하여 2차 상등액과 2차 침전물로 구분해야 한다.There is no concentration limit of sodium hydroxide titrated to the cerium chloride composition to form a reaction system, but in order to achieve the object of the present invention to provide a high-purity cerium oxide powder, the acidity of the reaction system may be adjusted to pH 10-11. Sodium hydroxide should be titrated to distinguish the secondary supernatant from the secondary precipitate.
1차 정제 단계에서 여과 회수된 1차 침전물에 수산화나트륨이 적정되어 이루어지는 반응계의 산도가 pH 10 미만이면 상기 반응계가 2차 상등액과 2차 침전물로 충분하게 구분되지 않으며, 1차 침전물에 수산화나트륨이 적정되어 이루어지는 반응계의 산도가 pH 11을 초과하면 세륨클로라이드 조성물에 함유된 La이 2차 상등액에 제대로 분산되지 않는다.If the acidity of the reaction system in which sodium hydroxide is titrated to the primary precipitate filtered out in the first purification step is less than pH 10, the reaction system is not sufficiently classified into a secondary supernatant and a secondary precipitate, and sodium hydroxide is added to the primary precipitate. When the acidity of the reaction system that is titrated exceeds pH 11, La contained in the cerium chloride composition does not disperse properly in the secondary supernatant.
상기와 같이 2차 상등액과 2차 침전물로 구분된 반응계를 여과하여, La이 대폭 저감되어 정제된 상태인 2차 침전물을 회수하므로써 2차 정제 단계가 실시된다.As described above, by filtering the reaction system divided into the secondary supernatant and the secondary precipitate, the secondary purification step is carried out by recovering the secondary precipitate in a state in which La is greatly reduced and purified.
또한, 본 발명의 고순도 산화세륨 분말의 제조 방법은 상기 2차 침전물에 함유된 Pr을 저감하도록 정제수를 미세 분사하고 여과하여 고상의 세륨 전구체를 수득하는 수세 단계가 포함된다.In addition, the method for producing a high purity cerium oxide powder of the present invention includes a washing step of obtaining a solid cerium precursor by fine spraying and filtering purified water to reduce Pr contained in the secondary precipitate.
세륨클로라이드 조성물에 함유된 Pr은 세륨과의 결합력이 매우 강력하고 용해성도 낮아서 pH 조절제를 사용하는 정제 과정, 즉 상기 1차 정제 단계 및 2차 정제 단계에서도 제거되지 않고 그대로 잔존하게 되며, 별도의 Pr 제거 과정을 거치지 않을 경우 세륨 전구체에 그대로 잔존하게 되며, 상기 잔존된 Pr이 세륨 전구체의 열처리 과정에서 산화되어 Pr6O11로 변환되어 산화세륨에 함유된다.Pr contained in the cerium chloride composition is very strong and low solubility in cerium chloride composition so that it remains intact without being removed even in the purification process using a pH adjuster, that is, the first and second purification steps, and a separate Pr If not removed, it remains in the cerium precursor as it is, and the remaining Pr is oxidized during the heat treatment of the cerium precursor and converted into Pr 6 O 11 to be contained in cerium oxide.
따라서, 본 발명에서는 2차 정제 단계에서 여과 회수된 2차 침전물에 함유된 Pr을 저감하기 위하여, 상기 회수된 2차 침전물에 과량의 정제수를 가하여 2차 침전물에 함유된 Pr을 분산시키되, 상기 2차 침전물 전체를 효과적으로 수세하여 함유된 Pr을 제거하도록, 정제수를 미세한 물방울로 분쇄하여 분사할 수 있는 미세 분사 샤워기로 정제수를 미세 분사하여 수세하고, 상기 2차 침전물과 정제수의 혼합물을 여과하여 고상의 세륨 전구체를 회수한다.Therefore, in the present invention, in order to reduce the Pr contained in the secondary precipitate filtered and recovered in the secondary purification step, an excess of purified water is added to the recovered secondary precipitate to disperse Pr contained in the secondary precipitate, In order to effectively wash the whole sediment to remove the contained Pr, the purified water is finely rinsed with a fine spray shower that can be pulverized and sprayed purified water into fine droplets, and the mixture of the secondary precipitate and purified water is filtered Recover the cerium precursor.
구체적으로, 2차 침전물에 그 100배 중량의 정제수를 미세 분사 샤워기로 미세 분사하여 상기 2차 침전물에 함유된 Pr을 정제수로 분산시키고, 상기 정제수와 2차 침전물의 혼합물을 여과하여 고상의 세륨 전구체를 수득한다. 상기와 같은 수세 단계에서 과량의 정제수의 미세 분산에 의해 2차 침전물에 함유된 라피네이트인 Pr이 상기 정제수로 분산하게 되는 반면, 수세된 세륨 전구체에서는 Pr의 함량이 그만큼 저감되는 것이다. Specifically, 100 times the weight of purified water to the secondary precipitate finely sprayed with a fine spray shower to disperse the Pr contained in the secondary precipitate with purified water, and the mixture of the purified water and the secondary precipitate is filtered to give a solid cerium precursor To obtain. In the washing step as described above, Pr, which is a raffinate contained in the secondary precipitate, is dispersed in the purified water by fine dispersion of excess purified water, whereas the content of Pr is reduced by the washed cerium precursor.
이러한 수세 단계를 5회 반복 실시하여 세륨 전구체를 구성하는 것이, 세륨 전구체에 함유된 Pr이 상기 세륨 전구체로부터 제조되는 산화세륨 분말과 상기 산화세륨 분말을 함유하는 CMP 슬러리의 물성에 악영향을 미치지 않을 정도로, 상기 세륨 전구체의 Pr 함량을 충분히 저감할 수 있다는 측면에서 바람직하다.Repeating this washing step five times to construct the cerium precursor is such that Pr contained in the cerium precursor does not adversely affect the physical properties of the cerium oxide powder prepared from the cerium precursor and the CMP slurry containing the cerium oxide powder. It is preferable at the point which can fully reduce the Pr content of the cerium precursor.
상기에서 기술된 2차 침전물에 대한 수세 단계를 5회 반복 실시하게 되면 Pr 함량이 100 ppm 미만인 세륨 전구체를 수득할 수 있다.Repeating the washing step with the secondary precipitate described above five times can yield a cerium precursor having a Pr content of less than 100 ppm.
또한, 본 발명의 고순도 산화세륨 분말의 제조 방법은 상기 세륨 전구체에 질산을 적정하여 세륨나이트레이트 수화물을 형성하는 단계가 포함된다.In addition, the method for producing a high purity cerium oxide powder of the present invention includes the step of titrating nitric acid to the cerium precursor to form cerium nitrate hydrate.
구체적으로, 수세 단계에 의해 Pr 함량이 대폭 저감된 상태로 수득된 세륨 전구체에 과량의 질산을 혼합하여 치환 반응을 유도하므로써 세륨 유도물질인 세륨나이트레이트 수화물을 형성하되, 세륨 전구체에 질산을 일시에 공급하게 되면 반응계에서 발열 반응이 심하게 발생하므로, 세륨 전구체에 질산을 소량씩 공급하는 적정을 실시하여 발열 반응을 조절하면서 세륨 유도물질인 세륨나이트레이트 수화물을 형성하는 것이다.Specifically, by mixing an excess of nitric acid in the cerium precursor obtained in the state in which the Pr content is significantly reduced by the washing step to induce a substitution reaction to form a cerium nitrate cerium nitrate hydrate, the nitric acid to the cerium precursor at a time Since the exothermic reaction is severely generated in the reaction system, the titration is performed by supplying nitric acid to the cerium precursor in small amounts to form the cerium nitrate hydrate, which is a cerium-inducing substance, by controlling the exothermic reaction.
상기와 같이 구성되는 세륨나이트레이트 수화물에 액상법을 적용하여 산화세륨을 구성할 수 있다.The cerium oxide may be formed by applying the liquid phase method to the cerium nitrate hydrate constituted as described above.
또한, 본 발명의 고순도 산화세륨 분말의 제조 방법은 상기 세륨나이트레이트 수화물과 탄산 전구체 수용액을 혼합하고 침전 반응하여 3차 상등액과 3차 침전물로 구분하고 여과하여 상기 3차 침전물을 회수하는 단계가 포함된다.In addition, the method for producing a high purity cerium oxide powder of the present invention comprises the step of mixing the cerium nitrate hydrate and the aqueous solution of the carbonic acid precursor and precipitation reaction to separate the tertiary supernatant and the tertiary precipitate and to recover the tertiary precipitate by filtration. do.
세륨 유도물질인 세륨나이트레이트 수화물에 우레아 수용액 등과 같은 탄산 전구체 수용액을 일정 함량 혼합하고, 일정한 시간동안 방치하여 침전 반응을 유도하여 3차 상등액과 3차 침전물로 구분하고, 상기 구분된 3차 상등액과 3차 침전물을 여과하여 3차 침전물을 회수한다.A predetermined amount of a carbonic acid precursor solution such as urea solution is mixed with cerium nitrate hydrate, which is a cerium-derived substance, and left to stand for a predetermined time to induce precipitation reaction. The third precipitate is filtered to recover the third precipitate.
상기와 같이 세륨나이트레이트 수화물과 탄산 전구체 수용액을 혼합하고 침전 반응을 유도하는 단계에서 상기 세륨나이트레이트 수화물과 탄산 전구체 수용액 사이에서 치환 반응이 발생하여 산화세륨인 3차 침전물이 형성된다. 상기 형성된 3차 침전물은 세라나이트에 함유되었던 라피네이트인 La, Ce, Nd 등이 대폭 저감되고 특히 연마재로서의 품질에 큰 영향을 미치는 Pr의 함량이 100 ppm 미만으로 저감되는 특성을 지니고 있다.In the step of mixing the cerium nitrate hydrate and the carbonic acid precursor aqueous solution as described above and inducing a precipitation reaction, a substitution reaction occurs between the cerium nitrate hydrate and the carbonic acid precursor aqueous solution to form a tertiary precipitate which is cerium oxide. The formed tertiary precipitate is characterized in that the raffinate La, Ce, Nd and the like contained in the ceraneite is greatly reduced, and in particular, the content of Pr, which greatly affects the quality as an abrasive, is reduced to less than 100 ppm.
또한, 본 발명의 고순도 산화세륨 분말의 제조 방법은 상기 3차 침전물을 일정한 온도로 소성하고 분쇄하여 산화세륨 분말을 형성하는 단계가 포함된다.In addition, the method for producing a high purity cerium oxide powder of the present invention includes the step of firing and pulverizing the tertiary precipitate at a constant temperature to form a cerium oxide powder.
세륨 나이트레이트 수화물로부터 형성되는 3차 침전물인 산화세륨을 900∼1000 ℃로 열처리하여 고화시키고, 상기 고화된 산화세륨을 분쇄하여 산화세륨 분말을 형성한다.Cerium oxide, a tertiary precipitate formed from cerium nitrate hydrate, is heat-treated at 900 to 1000 ° C. to solidify, and the solidified cerium oxide is pulverized to form cerium oxide powder.
3차 침전물인 산화세륨의 열처리 온도가 900 ℃ 미만이면 상기 산화세륨이 제대로 결정화되지 않으며, 3차 침전물인 산화세륨의 열처리 온도가 1000 ℃를 초과하면 상기 산화세륨 입자가 강력하게 결착하여 산화세륨의 분산성이 저하된다.If the heat treatment temperature of cerium oxide, the third precipitate, is lower than 900 ° C., the cerium oxide is not crystallized properly. If the heat treatment temperature of the cerium oxide, the third precipitate, exceeds 1000 ° C., the cerium oxide particles are strongly bound to form cerium oxide. Dispersibility falls.
3차 침전물인 산화세륨에 함유된 Pr의 함량이 100 ppm 미만이므로, 상기 산화세륨에 함유된 Pr이 소성 과정에서 산화되어 발생하는 산화물인 Pr6O11의 함량 역시 극히 작아서, 고화된 산화세륨을 분쇄하여 형성되는 산화세륨 분말의 연마 기능에 영향을 미치지 않는다.Since the content of Pr in the cerium oxide, which is a tertiary precipitate, is less than 100 ppm, the content of Pr 6 O 11 , which is an oxide produced by the oxidation of Pr in the cerium oxide during the calcination process, is also extremely small. It does not affect the polishing function of the cerium oxide powder formed by grinding.
즉, 상기에서 기술된 산화세륨 분말의 제조 방법에 의하여 제조된 고순도 산화세륨 분말은 Pr 함량이 100 ppm 미만인 세륨나이트레이트 수화물로부터 형성되어, Pr의 산화물인 Pr6O11의 함량이 극히 작기 때문에, 산화세륨 분말의 입도 분포가 균일하여 연마 특성을 크게 향상시킬 수 있다.That is, the high-purity cerium oxide powder prepared by the above-described method for producing cerium oxide powder is formed from cerium nitrate hydrate having a Pr content of less than 100 ppm, so that the content of Pr 6 O 11 , an oxide of Pr, is extremely small. The particle size distribution of the cerium oxide powder is uniform, which can greatly improve the polishing characteristics.
또한, 상기 고순도 산화세륨 분말을 연마재로 혼합하여 CMP 슬러리를 구성한다. 이러한 CMP 슬러리 역시 Pr6O11의 함량이 극히 작기 때문에 연마 속도를 크게 향상시킬 수 있으며, 연마 대상물에서 스크래치가 거의 발생하지 않는다.In addition, the high purity cerium oxide powder is mixed with an abrasive to form a CMP slurry. This CMP slurry can also greatly improve the polishing rate because the content of Pr 6 O 11 is extremely small, and scratches hardly occur in the polishing object.
종래의 CMP 슬러리에 의하여 연마된 8인치 웨이퍼에서 4∼15 개의 스크래치가 발생하는 반면, 본 발명에 의한 CMP 슬러리로 연마된 8인치 웨이퍼에서는 스크래치가 발생하지 않거나 1개 정도의 스크래치가 발생할 뿐이므로, 상기 웨이퍼를 사용하여 제조되는 전자제품의 품질을 보장하는 효과를 지니고 있다.On the 8-inch wafer polished with the conventional CMP slurry, 4 to 15 scratches occur, whereas the 8-inch wafer polished with the CMP slurry according to the present invention does not generate scratches or only about one scratch. It has the effect of ensuring the quality of electronic products manufactured using the wafer.
Claims (4)
- 세륨클로라이드 조성물이 pH 9∼10이 되도록 수산화나트륨을 적정하여 1차 상등액과 1차 침전물로 구분하고 여과하여 상기 1차 침전물을 회수하는 1차 정제 단계; 상기 1차 침전물의 산도가 pH 10∼11이 되도록 수산화나트륨을 적정하여 2차 상등액과 2차 침전물로 구분하고 여과하여 상기 2차 침전물을 회수하는 2차 정제 단계; 상기 2차 침전물에 함유된 프라세오디움(Pr)을 저감하도록 정제수를 미세 분사하고 여과하여 Pr 함량이 100 ppm 미만인 고상의 세륨 전구체를 수득하는 수세 단계; 상기 세륨 전구체에 질산을 적정하여 세륨나이트레이트 수화물(Ce(NO3)3·6H2O)을 형성하는 단계; 상기 세륨나이트레이트 수화물과 탄산 전구체 수용액을 혼합하고 침전 반응하여 3차 상등액과 3차 침전물로 구분하고 여과하여 상기 3차 침전물을 회수하는 단계; 및 상기 3차 침전물을 900∼1000 ℃로 소성하고 분쇄하여 프라세오디움 함량이 100 ppm 미만으로 함유된 산화세륨 분말을 형성하는 단계를 포함하는 것을 특징으로 하는 고순도 산화세륨 분말의 제조 방법.A first purification step of titrating sodium hydroxide so that a cerium chloride composition has a pH of 9 to 10, separating the primary supernatant and the primary precipitate, and filtering the primary precipitate to recover the primary precipitate; A second purification step of titrating sodium hydroxide so that the acidity of the primary precipitate is pH 10-11, divided into a secondary supernatant and a secondary precipitate, and filtering to recover the secondary precipitate; A water washing step of finely spraying purified water and filtering to reduce prasedium (Pr) contained in the secondary precipitate to obtain a solid cerium precursor having a Pr content of less than 100 ppm; Titrating nitric acid on the cerium precursor to form cerium nitrate hydrate (Ce (NO 3 ) 3 .6H 2 O); Mixing the cerium nitrate hydrate and an aqueous solution of a carbonic acid precursor and precipitating the reaction to separate the tertiary supernatant and the tertiary precipitate and recover the tertiary precipitate by filtration; And calcining the tertiary precipitate at 900 to 1000 ° C. and pulverizing to form a cerium oxide powder containing a prasedium content of less than 100 ppm.
- 제 1 항에 있어서, The method of claim 1,상기 수세 단계를 5회 반복 실시하여 세륨 전구체를 구성하는 것을 특징으로 하는 고순도 산화세륨 분말의 제조 방법.Method for producing a high purity cerium oxide powder, characterized in that the washing step is repeated five times to form a cerium precursor.
- 제 1 항의 방법에 의하여 제조되어 프라세오디움 함량이 100 ppm 미만으로 함유된 고순도 산화세륨 분말.A high purity cerium oxide powder prepared by the method of claim 1, which contains a prasedium content of less than 100 ppm.
- 제 1 항의 방법에 의하여 제조되어 프라세오디움 함량이 100 ppm 미만으로 함유된 고순도 산화세륨 분말을 포함하는 CMP 슬러리.A CMP slurry comprising a high purity cerium oxide powder prepared by the method of claim 1 and containing a prasedium content of less than 100 ppm.
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| JPH062582B2 (en) * | 1987-12-02 | 1994-01-12 | 多木化学株式会社 | Crystalline ceric oxide sol and method for producing the same |
| KR20030081942A (en) * | 2002-04-15 | 2003-10-22 | 주식회사 엘지화학 | Mehtod for preparing single craystalline cerium oxide powders |
| US20070107318A1 (en) * | 2005-11-14 | 2007-05-17 | Oh Myoung H | Cerium carbonate powder, cerium oxide powder, method for preparing the same, and CMP slurry comprising the same |
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| JPH062582B2 (en) * | 1987-12-02 | 1994-01-12 | 多木化学株式会社 | Crystalline ceric oxide sol and method for producing the same |
| KR20030081942A (en) * | 2002-04-15 | 2003-10-22 | 주식회사 엘지화학 | Mehtod for preparing single craystalline cerium oxide powders |
| US20070107318A1 (en) * | 2005-11-14 | 2007-05-17 | Oh Myoung H | Cerium carbonate powder, cerium oxide powder, method for preparing the same, and CMP slurry comprising the same |
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