Cerium carbonate powder, method for preparing the same, cerium oxide powder made therefrom, method for preparing the same, and CMP slurry comprising the same

a technology of cerium oxide and cerium carbonate, which is applied in the field of cerium oxide powder made therefrom method for preparing same, etc., can solve the problems of difficult to prepare particles with a high crystallinity, above method is not amenable to mass production, and above method is dangerous, so as to achieve easy control of size and shape

Inactive Publication Date: 2007-04-12
LG CHEM LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0008] Therefore, the present invention has been made in view of the above-mentioned problems. The inventors of the present invention have found that when cerium carbonate powder is prepared by using an organic solvent as a solvent for forming at least one precursor solution of a cerium precursor solution and a carbonate precursor solution, it is possible to control the size and shape of the resultant cerium carbonate powder from the initial stage of powder preparation, and thus to easily control the size and shape of cerium oxide powder that may be prepared from the cerium carbonate powder.
[0017] According to the prior art, water is used as a solvent for a cerium precursor solution as well as a carbonate precursor solution during preparation of cerium carbonate powder. On the contrary, the present invention is characterized by using an organic solvent as a solvent for at least one of a cerium precursor solution and a carbonate precursor solution, so as to control the size and shape of the resultant cerium carbonate powder.
[0019] Therefore, according to the present invention, it is possible to control the size and shape of cerium carbonate powder by adjusting the dielectric constant of a solvent. Particularly, this can be accomplished effectively by using various organic solvents having different dielectric constant.
[0033] Preferably, precipitation can be performed for 30 minutes˜60 hours. As can be seen from the following examples, a longer precipitation time provides a smaller particle size of cerium carbonate powder. It is thought that this is because the organic solvent contained in the solvent may serve as a reducing agent. Additionally, as the precipitation time increases, reaction degree also increases, which may affect the crystallinity of the resultant powder.
[0038] Since the cerium oxide powder according to the present invention is obtained by using the cerium carbonate powder obtained from the aforementioned method as a precursor, the size and shape of the cerium carbonate powder affect those of the cerium oxide powder. In other words, the cerium oxide powder according to the present invention has a tendency to have a size and shape similar to those of the precursor, cerium carbonate powder. If is a matter of course that cerium carbonate powder may be cracked on surfaces or broken during the preparation of cerium oxide via heat treatment of cerium carbonate. Thus, the size and shape of cerium carbonate cannot be retained in the resultant cerium oxide. However, it is possible to control the size and shape of cerium oxide powder with ease by controlling the size and shape of cerium carbonate powder.

Problems solved by technology

Although the former process is useful for preparing fine particles because particles grow from a nucleation step, it has difficulty in preparing particles with a high crystallinity.
On the other hand, the latter process has a disadvantage in that it produces macroparticles, which, in turn, should be processed into powder with a desired size by using a pulverization step.
However, the above method is not amenable to mass production.
However, the above method is dangerous because it should be carried out at high temperature under high pressure.
Also, the above method is not cost-efficient due to the cost required for the reaction system.
However, the above method has difficulty in providing a mass production system and is not amenable to bulk production.

Method used

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  • Cerium carbonate powder, method for preparing the same, cerium oxide powder made therefrom, method for preparing the same, and CMP slurry comprising the same
  • Cerium carbonate powder, method for preparing the same, cerium oxide powder made therefrom, method for preparing the same, and CMP slurry comprising the same
  • Cerium carbonate powder, method for preparing the same, cerium oxide powder made therefrom, method for preparing the same, and CMP slurry comprising the same

Examples

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Effect test

example 1

[0057] First, 0.1 mole of cerium nitrate anhydrate was dissolved into 100 ml of distilled water, and the solution was stirred at room temperature for 30 minutes. In a separate container, 0.2 mole of ammonium carbonate was dissolved into 100 ml of ethanol at 50° C. Then, the above two solutions were mixed with each other to cause precipitation at 75° C. for 6 hours. By doing so, cerium carbonate powder was obtained.

[0058] The resultant cerium carbonate powder had a cubic structure and a uniform size of 100 nm. The particle shape is shown in FIG. 1 by using SEM at a magnification of ×20,000 (herein, each scale bar has a length of 2 μm). Additionally, crystallinity of the resultant powder is shown in FIG. 8 by using XRD.

example 2

[0059] Cerium carbonate powder was obtained in the same manner as described in Example 1, except that 1,4-butanediol was used instead of ethanol and the reaction was performed at a temperature of 85° C. instead of 75° C.

[0060] The resultant cerium carbonate powder (cerium oxide carbonate hydrate-Ce(CO3)2O.H2O) had an orthorhombic structure and a size of about 2˜3 μm. The particle shape is shown in FIG. 2 by using SEM at a magnification of ×10,000 (herein, each scale bar has a length of 5 μm). Additionally, crystallinity of the resultant powder is shown in FIG. 8 by using XRD.

example 3

[0061] Cerium carbonate powder was obtained in the same manner as described in Example 1, except that ethylene glycol was used instead of ethanol and the reaction was performed at a temperature of 85° C. instead of 75° C.

[0062] The resultant cerium carbonate powder (cerium oxide carbonate hydrate-Ce(CO3)2O.H2O) had an orthorhombic structure and a size of about 500˜600 nm. The particle shape is shown in FIG. 3 by using SEM at a magnification of ×20,000 (herein, each scale bar has a length of 2 μm). Additionally, crystallinity of the resultant powder is shown in FIG. 8 by using XRD.

[0063] In the above Example 1, the reaction was performed at 75° C., which was lower than the boiling point of ethanol. As can be seen from Examples 1˜3, it is possible to vary the size and shape of cerium carbonate particles by varying the organic solvent used in the cerium precursor and carbonate precursor.

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Abstract

Disclosed is a method for preparing cerium carbonate powder by mixing a cerium precursor solution with a carbonate precursor solution to cause precipitation, wherein at least one solvent used in the cerium precursor solution and the carbonate precursor solution is an organic solvent. Cerium carbonate powder obtained from the method, cerium oxide powder obtained from the cerium carbonate powder, a method for preparing the cerium oxide powder, and CMP slurry comprising the cerium oxide powder are also disclosed. The method for preparing cerium carbonate using an organic solvent, allows the resultant cerium carbonate powder to have a size and shape controllable from the initial nucleation step. Additionally, it is possible to easily control the size and shape of cerium oxide powder obtained from the cerium carbonate powder.

Description

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 2005-87377, filed on Sep. 20, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD [0002] The present invention relates to a method for preparing cerium carbonate powder, which uses an organic solvent having a dielectric constant different from that of water so as to control size and shape of cerium carbonate powder, cerium carbonate powder obtained by the same method, cerium oxide powder obtained from the cerium carbonate powder, a method for preparing the cerium oxide powder, and CMP slurry comprising the cerium oxide powder as an abrasive. BACKGROUND ART [0003] In general, cerium oxide is a high functional ceramic material that is widely used in catalysts, phosphors, cosmetics and abrasives. Recently, cerium oxide has been spotlighted as an abrasive in a STI (Shallow Trench Isolation) process and a...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B24D3/02C01F17/235
CPCC01F17/0043C01F17/005C01P2002/72C01P2004/03C01P2004/61C01P2004/62C01F17/247C01F17/235C01F17/10C01P2004/64
Inventor OH, MYOUNG HWANNHO, JUN SEOKKIM, JONG PILKIM, JANG YULCHO, SEUNG BEOM
Owner LG CHEM LTD
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