WO2014208379A1

WO2014208379A1 - Abrasive, method for producing abrasive, and polishing method

Info

Publication number: WO2014208379A1
Application number: PCT/JP2014/065873
Authority: WO
Inventors: 啓介溝口; 前澤　明弘; 高橋　篤; 奈津紀伊藤; 奈津実平山; 若松　秀明; 佑樹永井; 智恵乾
Original assignee: コニカミノルタ株式会社
Priority date: 2013-06-27
Filing date: 2014-06-16
Publication date: 2014-12-31
Also published as: TWI523943B; JP6424818B2; JPWO2014208379A1; TW201510198A

Abstract

The present invention addresses the problem of providing an abrasive containing abrasive particles which is highly producible, is appropriate for precision polishing, and is capable of maintaining the polishing speed of the initial polishing interval for a long time. This abrasive contains abrasive particles comprising: at least 81 mol% in total of one or more types of elements selected from cerium (Ce), lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), and europium (Eu); and no more than 19 mol% in total of yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Furthermore, the abrasive is characterized in that the monodispersity of the particle diameter of the abrasive particles is 30% or less.

Description

Abrasive material, method for producing abrasive material, and polishing method

The present invention relates to an abrasive, a method for manufacturing an abrasive, and a polishing method. More specifically, the present invention relates to an abrasive having improved polishing performance, a method for producing the abrasive, and a polishing method using the abrasive.

As a polishing material for precision polishing of glass optical elements, glass substrates, and semiconductor devices in the manufacturing process, a rare earth element oxide with cerium oxide as the main component and lanthanum oxide, neodymium oxide, praseodymium oxide, etc. added to it has been used. Has been. Other abrasives include diamond, iron oxide, aluminum oxide, zirconium oxide, colloidal silica, etc., but when compared in terms of polishing rate and surface roughness of the polished object, cerium oxide Is known to be effective and is used extensively.

Until now, cerium oxide particles were mainly prepared by wet pulverization method, but the shape of cerium oxide particles obtained by wet pulverization method is non-uniform, and polishing properties (smoothness of polishing surface and polishing rate) ) Is also inferior.
Therefore, in a manufacturing process that requires high smoothness of angstrom (Å) level, it is common to polish using cerium oxide or the like having a high polishing rate and then polishing using colloidal silica of several tens of nanometers. is there.
However, there is a problem that productivity is lowered due to the multi-stage polishing process. In addition, there is an increasing demand for smoothness, and there is a demand for an abrasive that generates few scratches while maintaining a high polishing rate.

In response to such problems, cerium oxide abrasives containing cerium oxide particles having fine and high monodispersity prepared by a wet synthesis method have recently been studied. The method of obtaining cerium oxide particles by this wet synthesis method is mainly performed by adding a salt of carbonic acid, oxalic acid, acetic acid or the like to a purified aqueous solution of cerium nitrate, cerous chloride, cerous sulfate or the like. This is a method of precipitating cerium carbonate, cerium oxalate, cerium acetate, and other products, filtering this precipitate, drying it, and firing it to obtain cerium oxide particles. It has been attracting attention as a technique that can achieve both smoothness and a high polishing rate.

For example, Non-Patent Document 1 proposes a method of obtaining particles having a narrow particle size distribution by heating and stirring an aqueous solution in which a cerium nitrate aqueous solution, an yttrium nitrate solution, and urea are mixed.
However, as a result of firing the particles produced by the method of Non-Patent Document 1 and confirming the effect as an abrasive, the polishing rate was low. The cause of reducing the polishing rate is that elements other than cerium (yttrium) are mixed to adjust the particle shape and particle size distribution, thereby reducing the cerium concentration on the particle surface and reducing the polishing rate. ing.

In Patent Document 1, in addition to cerium, at least one element selected from lanthanum, praseodymium, neodymium, samarium, europium and at least 1 selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. A method of obtaining spherical rare earth oxide particles by adding a urea compound to an aqueous solution containing salts of various elements to form a spherical rare earth basic carbonate and firing it is described. ing.
However, in this method, spherical particles cannot be obtained unless at least one element selected from yttrium and gadolinium is contained in a proportion of 20 mol% or more.

In Patent Document 2 and Patent Document 3, gadolinium, terbium, europium, samarium, neodymium, dysprosium, holmium, erbium, thulium, and ytterbium are used as methods for obtaining spherical monodisperse rare earth oxide particles. An example is given.
However, there is no description of a method for obtaining cerium spherical monodisperse oxide particles.

Non-Patent Document 2 describes a method for preparing rare earth element oxides by adding urea to a mineral salt aqueous solution of rare earth elements, heating to precipitate an insoluble salt of rare earth elements, and firing the salt. Yes.
However, when the synthetic scale is increased, particles that grow anisotropically are generated instead of spherical particles.

Moreover, in patent document 4, manufacture of the metal oxide particle obtained by baking the metal oxide which a metal oxide particle produces | generates by heating the mixture containing a metal salt, a high molecular compound, and a high boiling point organic solvent. The method is described.
However, in the method of Patent Document 4, since the crystallites are aggregated to form particles, the shape is not a true sphere, and the surface has many irregularities and is easily scratched. Moreover, since it is a particle | grains which consist of an agglomerated particle, when using for grinding | polishing process, it is easy to disintegrate.

Furthermore, since an organic solvent is used as a solvent and a reaction at a high temperature is required, productivity is poor. In addition, since a polymer is used, if the polymer remains on the particle surface, aggregation occurs during firing, which makes it difficult to control the particle diameter.
In polishing with cerium oxide particles, a large amount of trivalent cerium atoms are present on the surface of cerium oxide, and tetravalent cerium atoms are stably present inside the particles, so that the trivalent cerium on the surface can be polished. It is believed that polishing proceeds by cutting the molecular bonds. However, in the particles described in Patent Document 4 which is an aggregate of small particles, a difference in valence of cerium atoms hardly appears on the particle surface and inside, and trivalent particles hardly exist on the surface. Increase is not expected.

Patent Document 5 uses a mixed rare earth fluorine compound having an average crystallite diameter within a range of 20 to 40 nm (200 to 400 mm) obtained by firing at a temperature range of 700 to 1300 ° C. for 1 to 10 hours. A method for producing a cerium-based abrasive has been disclosed. In this method, a cerium-based abrasive is obtained by mixing and grinding a mixed rare earth oxide and a mixed rare earth fluoride.

However, since the cerium-based abrasive obtained by the method of Patent Document 5 has a low cerium concentration on the outermost surface of the particles, a sufficient polishing rate cannot be obtained. Further, in Patent Document 5, cerium oxide particles having an average crystallite diameter exceeding 400 mm have a difficulty in progressing the fluorination reaction, and a high polishing rate cannot be obtained.

Usually, the polishing process includes primary polishing where the polishing speed is more important than polishing accuracy, and secondary polishing where emphasis is placed on smoothness and surface uniformity which are the final finished quality. In polishing a hard glass substrate, polishing speed is more important than smoothness and surface accuracy, and development of an abrasive suitable for a primary polishing process that affects the overall polishing efficiency is desired.

International Publication No. 2012/101871 US Pat. No. 5,015,452 Japanese Patent Laid-Open No. 11-35320 JP 2013-110272 A JP 2006-097014 A

The present invention has been made in view of the above-mentioned problems, and the solution is to include abrasive particles that are high in productivity and suitable for precision polishing, and can maintain the initial polishing rate for a long period of time. It is to provide an abrasive material. Moreover, it is providing the manufacturing method of the abrasive | polishing material containing the said abrasive particle, and the grinding | polishing processing method using the said abrasive | polishing material.

The present inventor has been made in view of the above problems and situations, and the solution is to include cerium in the process of examining the relationship between the composition and shape of the abrasive particles, and is suitable for precision polishing. The present inventors have found an abrasive containing abrasive particles and have reached the present invention.
In addition, as a result of examining the relationship between the shape of the abrasive particles and particle growth, etc., the process of forming abrasive precursor particles is divided into a nucleation process at the initial stage of reaction and a growth process of particles that grow the generated nuclei. In the process, an aqueous solution of heat-decomposed ureas, which is a raw material for abrasive precursor particles, is added to an aqueous solution of a rare earth element-containing compound containing cerium (hereinafter also referred to as an aqueous rare earth salt solution) to quickly form abrasive precursor particles. The inventors have found that it is important to form nuclei at a stage and grow them in order to produce abrasive particles having excellent monodispersibility and a preferable shape.
Also, a cerium oxide abrasive containing cerium oxide particles not containing fluorine element, wherein the average crystallite diameter of the cerium oxide particles is in a range of 420 to 500 mm, and the particle diameter of the cerium oxide particles A cerium oxide abrasive that is suitable for the primary polishing process, has a high polishing rate, and can maintain the initial polishing rate over a long period of time due to the cerium oxide abrasive having a monodispersity of 30% or less The inventors have also found out that the present invention can be provided, and have reached the present invention.
That is, the said subject of this invention is solved by the following means.

1. Cerium (Ce),
With at least one element selected from lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm) and europium (Eu),
The total content is 81 mol% or more,
At least one selected from yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) Containing abrasive particles having an elemental content of 19 mol% or less,
An abrasive having a monodispersity of particle size of the abrasive particles of 30% or less.

2. 2. The abrasive according to item 1, wherein an average crystallite diameter of the abrasive particles is in the range of 420 to 500 mm.

3. 3. The abrasive according to item 1 or 2, wherein an average particle diameter D ₅₀ of the abrasive particles is in the range of 0.5 to 0.9 μm.

4. 4. The abrasive according to any one of items 1 to 3, wherein an average content of the abrasive particles is 80% by mass or more of all abrasive particles.

5. The content of cerium (Ce) is 81 mol% or more,
At least one selected from yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) The abrasive | polishing material as described in any one of the 1st term | claim to the 4th term | claim characterized by containing the abrasive | polishing material particle whose content of said element is 19 mol% or less.

6). The content of cerium (Ce) is 90 mol% or more,
At least one selected from yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) The abrasive | polishing material as described in any one of the 1st term | claim to the 5th term | claim characterized by containing the abrasive | polishing material particle whose content of said element is 10 mol% or less.

7). Containing abrasive particles in which the content of cerium (Ce) is in the range of 95 to 100 mol%,
An abrasive having a monodispersity of particle size of the abrasive particles of 30% or less.

8. The abrasive according to item 7, wherein the abrasive particles have a monodispersity of particle size of 20% or less.

9. A manufacturing method for manufacturing the abrasive according to any one of items 1 to 8,
Contains abrasive particles characterized by including carbon dioxide gas continuously or intermittently into the following aqueous solution or reaction solution, including at least the following steps 1 to 5 and at least the following steps 2 to 3. A manufacturing method of an abrasive.
Step 1: Step of preparing and heating an aqueous solution containing cerium (Ce) Step 2: Step of preparing a reaction solution by adding a precipitant to the aqueous solution heated in Step 1 Step 3: Heating the reaction solution Step of stirring to generate abrasive particle precursor Step 4: Separating the abrasive particle precursor generated in Step 3 from the reaction solution Step 5: The abrasive particle obtained by separating in Step 4 A step of firing the precursor in an oxidizing atmosphere to form abrasive particles

10. Item 10. The method for producing an abrasive containing abrasive particles according to Item 9, wherein the aqueous solution satisfies the following requirements 1a to 3a.
Requirement 1a: In addition to cerium, the aqueous solution contains lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), yttrium (Y), gadolinium (Gd), terbium ( At least one element selected from 14 rare earth elements consisting of Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) contains.
Requirement 2a: The total content of cerium contained in the aqueous solution and at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium contained in the aqueous solution is contained in the aqueous solution. It is 81 mol% or more with respect to the whole quantity of rare earth elements.
Requirement 3a: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the whole of the rare earth elements contained in the aqueous solution It is 19 mol% or less with respect to quantity.

11. Item 11. The method for producing an abrasive containing abrasive particles according to Item 10, wherein the aqueous solution satisfies the following requirements 1b to 3b.
Requirement 1b: In addition to the cerium, the aqueous solution contains at least one element selected from nine kinds of rare earth elements consisting of yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. .
Requirement 2b: The content of cerium in the aqueous solution is 81 mol% or more with respect to the total amount of rare earth elements contained in the aqueous solution.
Requirement 3b: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the entire rare earth element contained in the aqueous solution It is 19 mol% or less with respect to quantity.

12. 10. The abrasive particles according to item 9, wherein the content of cerium in the aqueous solution is in the range of 95 to 100 mol% with respect to the total amount of rare earth elements contained in the aqueous solution. A manufacturing method of an abrasive.

13. Any one of Items 9 to 12, wherein the concentration of carbonate ions in the aqueous solution or the reaction solution immediately before adding the precipitant in Step 2 is in the range of 50 to 1600 mg / L. A method for producing an abrasive containing the abrasive particles according to claim 1.

14. Any one of Items 9 to 13, wherein the carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in Step 2 is in the range of 58 to 1569 mg / L. A method for producing an abrasive containing the abrasive particles according to claim 1.

15. Item 15. The method for producing an abrasive containing abrasive particles according to any one of Items 9 to 14, wherein the precipitant is urea or a urea-based compound.

16. A manufacturing method for manufacturing the abrasive according to any one of items 1 to 8,
Adding an aqueous urea solution to an aqueous solution of a rare earth element-containing compound containing cerium to form abrasive precursor particles;
Adding at least a step of firing the abrasive precursor particles, and adding an aqueous urea solution that is thermally decomposed in the nucleation process of the particles in the initial stage of the reaction in the step of forming the abrasive precursor particles,
A method for producing an abrasive containing abrasive particles, wherein an aqueous urea solution or an aqueous urea solution decomposed by heat decomposition is added in a particle growth process after the nucleation process.

17. The addition rate of the thermally decomposed urea aqueous solution added in the nucleation process of the particles at the initial stage of the reaction is in the range of 0.01 to 50 mol per minute per 1 liter of the reaction solution in terms of the urea concentration before the thermal decomposition. Item 18. A method for producing an abrasive containing the abrasive particles according to Item 16,

18. Item 18 or Item 17 is characterized in that the carbonate ion concentration of the thermally decomposed aqueous urea solution added in the nucleation process of the particles at the initial stage of reaction is in the range of 2.5 to 50 mmol / L. A method for producing an abrasive containing abrasive particles.

19. 19. The abrasive according to any one of items 16 to 18, wherein the concentration of the urea aqueous solution added in the particle growth process is in the range of 0.05 to 10 mol / L. A method for producing an abrasive containing particles.

20. Any one of Items 16 to 19, wherein a carbonate ion concentration of the thermally decomposed urea aqueous solution added in the process of growing the particles is in a range of 0.1 to 30 mmol / L. A method for producing an abrasive containing the abrasive particles according to Item.

21. A manufacturing method for manufacturing the abrasive according to any one of items 1 to 4,
The abrasive particles contained in the abrasive are produced by firing an abrasive particle precursor containing at least cerium oxide as a main component, and the firing treatment is performed at a firing temperature of 1050 to 1500 ° C. A method for producing an abrasive material, characterized in that the method comprises:

22. Item 22. The method for producing an abrasive according to Item 21, wherein the baking apparatus for baking the abrasive particle precursor in the baking step is a roller hearth kiln or a rotary kiln.

23. A polishing method, wherein the abrasive according to any one of items 1 to 8 is used for polishing an object to be polished.

By the above means of the present invention, it is possible to provide an abrasive containing abrasive particles having high productivity and suitable for precision polishing and capable of maintaining the initial polishing rate for a long period of time. Moreover, the manufacturing method of the abrasive | polishing material containing the said abrasive | polishing material particle and the grinding | polishing processing method using the said abrasive | polishing material can be provided.

The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The abrasive containing the abrasive particles can show a high polishing rate by containing cerium, but if an edge is present on the surface of the abrasive particles, it leads to generation of scratches during polishing. Therefore, by adding cerium to the abrasive particles and making it a specific composition, the polishing rate can be maintained, and it is effective for reducing the surface roughness of the object to be polished, which enables precision polishing. I found.
Conventionally, when polishing with abrasive particles having a large crystallite size, the polishing rate is high, but the surface roughness is generally rough. As the cause of the roughness of the surface, the polishing rate of each abrasive particle depends on the particle diameter, and if there is variation (distribution) in the particle diameter of the abrasive particles, the crystallite size increases. The difference in the polishing rate due to the effect of the particle diameter appears significantly, and the difference in the polishing rate on the surface of the object to be polished may appear as the roughness of the surface. That is, in order to ensure a high polishing rate and uniform surface roughness, an abrasive with excellent monodispersibility, uniform abrasive particle diameter, and large crystallite size is required.

Also, since the polishing rate of each abrasive particle is constant, the overall polishing rate is faster than when the polishing rate varies. Therefore, it is not necessary to form a fluorine compound as abrasive particles, and a fluorination step is not necessary.

As a result of investigations made by the present inventors, rather, by adding a fluorination step, the cerium content on the surface of each abrasive particle varies, so that the polishing rate for each abrasive particle is different. It has become clear that this causes a variation in polishing speed and a decrease in polishing rate.

It is considered that carbon dioxide and ammonia obtained by hydrolysis from urea or the like are necessary for the formation of the precursor of abrasive particles contained in the abrasive. Therefore, by introducing carbon dioxide into the dissolved reaction liquid such as carbon dioxide, ammonia and urea, the precursor of the abrasive particles can be efficiently obtained as basic carbonate, and precise polishing is possible. It has been found that the present invention is effective in a method for producing an abrasive containing abrasive particles containing certain spherical cerium.

Also, when forming spherical abrasive precursor particles, the heat-decomposed urea aqueous solution for nucleation is added to the rare earth salt aqueous solution at the beginning of the reaction to produce core particles with a uniform particle size distribution. I think that. It is considered that spherical abrasive precursor particles excellent in monodispersion can be obtained while maintaining the particle size distribution by subsequently adding a urea aqueous solution or a thermally decomposed urea aqueous solution as a raw material.

An example of a scanning photomicrograph of abrasive particles according to the present invention An example of a scanning photomicrograph of abrasive particles according to the present invention Schematic showing the crystallites of cerium oxide particles Electron micrograph showing an example of cerium oxide particles with crystallites The schematic diagram which shows an example of the flow of the manufacturing method of the abrasives which concerns on this invention The schematic diagram which shows an example of the flow of the manufacturing method of the abrasives which concerns on this invention The schematic diagram which shows an example of the flow of the manufacturing method of the abrasives which concerns on this invention The schematic diagram which shows an example of the flow of the manufacturing method of the abrasives which concerns on this invention

The abrasive of the present invention contains cerium (Ce) and at least one element selected from lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), and europium (Eu). Of yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and The content of at least one element selected from lutetium (Lu) contains abrasive particles of 19 mol% or less, and the monodispersity of the particle diameter of the abrasive particles is 30% or less. And
This feature is a technical feature common to the inventions according to claims 1 to 23.

As an embodiment of the present invention, the average crystallite size of the abrasive particles is preferably in the range of 420 to 500 mm from the viewpoint of obtaining a higher polishing rate.

As an embodiment of the present invention, the average particle diameter D ₅₀ of the abrasive particles is preferably in the range of 0.5 to 0.9 μm from the viewpoint of obtaining a higher polishing rate.

In addition, it is preferable that the average content of the abrasive particles is 80% by mass or more of the total abrasive particles from the viewpoint of obtaining a higher polishing rate.

As an embodiment of the present invention, the content of cerium (Ce) is 81 mol% or more, and yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium ( It is preferable to contain abrasive particles in which the content of at least one element selected from Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) is 19 mol% or less. This is because the polishing material particles have a high cerium content, thereby exhibiting an excellent polishing rate.

As an embodiment of the present invention, the content of cerium (Ce) is 90 mol% or more, and yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium ( The content of at least one element selected from Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu) is preferably 10 mol% or less. This suppresses the content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained together with cerium, thereby maintaining the production cost while maintaining the spherical shape. It is because it can suppress.

As an embodiment of the present invention, the abrasive particles having a cerium (Ce) content in the range of 95 to 100 mol% are contained, and the monodispersity of the particle diameter of the abrasive particles is 30% or less. It is preferable that the ratio of cerium is high because a high polishing rate can be obtained.

As an embodiment of the present invention, it is preferable that the monodispersity of the particle diameter of the abrasive particles is 20% or less because scratches are hardly generated and suitable for precision polishing.

An embodiment of the method for producing an abrasive containing abrasive particles of the present invention includes at least the following steps 1 to 5, and at least the following steps 2 to 3, carbon dioxide gas in the following aqueous solution or reaction solution: Is preferably introduced continuously or intermittently from the viewpoint of the effects of the present invention.
Step 1: Step of preparing and heating an aqueous solution containing cerium (Ce) Step 2: Step of preparing a reaction solution by adding a precipitant to the aqueous solution heated in Step 1 Step 3: Heating the reaction solution Step of stirring to generate abrasive particle precursor Step 4: Separating the abrasive particle precursor generated in Step 3 from the reaction solution Step 5: The abrasive particle obtained by separating in Step 4 A step of firing the precursor in an oxidizing atmosphere to form abrasive particles

As an embodiment of the present invention, it is preferable from the viewpoint of manifesting the effect of the present invention that the aqueous solution satisfies the requirements 1a to 3a.

In the present invention, it is preferable that the aqueous solution satisfies the requirements 1b to 3b in that spherical abrasive particles having a high cerium content and excellent polishing performance can be produced.

In the present invention, the cerium content of the aqueous solution is within the range of 95 to 100 mol% with respect to the total amount of rare earth elements contained in the aqueous solution, and the cerium content is high, Since it does not contain other elements, it is preferable in that the abrasive can be produced with a small number of production steps.

In the present invention, it is sufficient that the carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in Step 2 is in the range of 50 to 1600 mg / L. An amount of carbon dioxide gas can be introduced, which is preferable in that the supply amount of carbon dioxide gas can be controlled.

In the present invention, the carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in the step 2 is within the range of 58 to 1569 mg / L. It is preferable to make it more prominent.

In the present invention, it is preferable that the precipitating agent is urea or a urea-based compound in that carbon dioxide and ammonia can be supplied by a hydrolysis reaction.

As an embodiment of the method for producing an abrasive containing abrasive particles of the present invention, an aqueous urea solution is added to an aqueous solution of a rare earth element-containing compound containing cerium to form abrasive precursor particles, and A process of firing abrasive precursor particles, and adding an aqueous urea solution that is thermally decomposed in the nucleation process of particles at the initial stage of the reaction in the process of forming the abrasive precursor particles. It is preferable from the viewpoint of the effects of the present invention to add an aqueous urea solution or an aqueous urea solution decomposed by heat decomposition in the subsequent particle growth process.

As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, the addition rate of the thermally decomposed urea aqueous solution added in the nucleation process of the particles at the initial stage of the reaction is converted to the urea concentration before the thermal decomposition. Thus, it is preferably in the range of 0.01 to 50 mol per minute per 1 L of the reaction solution.

In the present invention, it is preferable that the carbonate ion concentration of the thermally decomposed aqueous urea solution added in the particle nucleation process at the initial stage of the reaction is in the range of 2.5 to 50 mmol / L.

In the present invention, it is preferable that the concentration of the urea aqueous solution added during the particle growth process is in the range of 0.05 to 10 mol / L.

In the present invention, it is preferable that the carbonate ion concentration of the thermally decomposed aqueous urea solution added during the particle growth process is in the range of 0.1 to 30 mmol / L.

Moreover, as an embodiment of the method for producing an abrasive material containing abrasive particles of the present invention, the abrasive particles contained in the abrasive material calcinate an abrasive particle precursor containing at least cerium oxide as a main component. In view of the effects of the present invention, the firing treatment is preferably a step of treating the firing temperature within a range of 1050 to 1500 ° C.

Further, in the present invention, it is possible to stably obtain abrasive particles having desired crystallites, that the baking apparatus for baking the abrasive particle precursor in the baking step is a roller hearth kiln or a rotary kiln. From the viewpoint of being able to.

In addition, it is preferable to use the abrasive of the present invention for polishing an object to be polished from the viewpoint of manifesting the effects of the present invention.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the following description, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

<Abrasive>
Common abrasives include those made by dispersing abrasive particles such as bengara (αFe ₂ O ₃ ), cerium oxide, aluminum oxide, manganese oxide, zirconium oxide, colloidal silica in water or oil to form a slurry. is there. The present invention is a chemical mechanical polishing method for polishing semiconductor devices and glass, in which polishing is performed by both physical action and chemical action in order to obtain a sufficient polishing rate while maintaining flatness with high accuracy. A polishing material containing cerium oxide capable of being subjected to (CMP; Chemical Mechanical Polishing) and a polishing method using the polishing material, the details of which will be described below.

<Abrasive particles>
The abrasive particles according to the present invention include cerium (Ce) and at least one element selected from lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), and europium (Eu). The total content is 81 mol% or more, and yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb ) And at least one element selected from lutetium (Lu) contains abrasive particles of 19 mol% or less, and the monodispersity of the particle diameter of the abrasive particles is 30% or less. Features.
Specifically, the abrasive particles according to the present invention necessarily contain cerium, and the total content of at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium is 81 mol% or more, It contains abrasive particles in which the content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium is 19 mol% or less, and the particle size of the abrasive particles is simply The degree of dispersion is 30% or less.

The abrasive particles always contain cerium, and need only contain at least one kind selected from lanthanum, praseodymium, neodymium, samarium and europium, and several kinds of elements are appropriately selected according to the performance of the intended abrasive. May be included.
The total content of cerium and at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium contained in the abrasive particles is 81 mol% or more, and yttrium, gadolinium, terbium, dysprosium, holmium, erbium In addition, the content of at least one element selected from thulium, ytterbium and lutetium is 19 mol% or less, and the monodispersity of the particle diameter of the abrasive particles is 30% or less, so that yttrium, gadolinium, terbium An abrasive exhibiting high polishing performance can be obtained while suppressing the content of at least one element selected from dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

(Measurement of average content (mol%) of rare earth elements in abrasive particles)
The content of each rare earth element in the abrasive particles contained in the abrasive can be determined by elemental analysis. For example, 1 g is dissolved in a mixed solution of 10 ml of nitric acid aqueous solution and 1.0 ml of hydrogen peroxide solution, and elemental analysis is performed using an ICP emission spectral plasma apparatus (ICP-AES) manufactured by SII Nano Technology. The composition ratio (mol%) can be determined from the content of each rare earth element in the abrasive particles.
The composition distribution of the abrasive particles may be determined by performing an elemental analysis of the cross section of the abrasive particles. For example, the abrasive particles are subjected to cross-section processing using a focused ion beam (FB-2000A) manufactured by Hitachi High-Technologies, and a surface passing through the vicinity of the particle center is cut out. From the cut surface, elemental analysis can be performed using STEM-EDX (HD-2000) manufactured by Hitachi High-Technologies to determine the composition distribution of each rare earth element in the abrasive particles.

(Monodispersity)
In the present invention, it is one of the characteristics that the monodispersity of the particle diameter of the abrasive particles according to the present invention is 30% or less, and the monodispersity is preferably 20% or less, particularly preferably 10%. % Or less.

Here, the monodispersity can be defined by a variation coefficient of a particle diameter distribution that can be obtained from a scanning micrograph (SEM image) of a predetermined number of abrasive particles.
For example, the coefficient of variation (also referred to as “monodispersity”) of the particle size distribution can be obtained from an SEM image of 100 abrasive particles, and the monodispersity can be evaluated. The particle diameter is determined based on the area of the photographic image of each particle, and the equivalent particle diameter is determined as the particle diameter of each particle.
The particle size distribution variation coefficient is obtained by the following formula.
Coefficient of variation (%) = (standard deviation of particle size distribution / average particle size) × 100
In addition, the measurement of the said particle diameter, distribution, etc. can be performed using an image processing measuring device (for example, Luzex AP; Nireco Corporation make).

The abrasive particles of the present invention are preferably spherical.
Here, the spherical shape is defined based on a scanning micrograph (SEM image) of the abrasive particles.
Specifically, a scanning micrograph is taken of the abrasive particles, and 100 abrasive particles are randomly selected. When the major axis of the selected abrasive particles is a and the minor axis is b, an average value of a / b is obtained as an aspect ratio. In addition, when drawing a circumscribing rectangle for each particle (referred to as “the circumscribing rectangle”), the shortest short side of the circumscribed rectangle is the shortest length, and the longest long side is the length. Is the major axis.
When the aspect ratio is in the range of 1.00 to 1.15, more preferably in the range of 1.00 to 1.05, it is classified as a spherical shape. If it is out of the range of 1.00 to 1.15, it is classified as indefinite.

¡The closer the aspect ratio is to 1, the higher the sphericity. The abrasive containing the abrasive particles according to the present invention having high sphericity is suitable for precision polishing and has a high polishing rate, and is excellent in terms of high productivity. A scanning photomicrograph (magnification 1000 times) of the abrasive particles according to the present invention is shown in FIG. Further, FIG. 2 shows the SEM image of FIG. It can be seen that it is spherical and has a high degree of monodispersity.

(Average particle diameter D ₅₀ of abrasive particles)
In the present invention, it is one of the preferred embodiments that the average particle diameter D ₅₀ of the abrasive particles according to the present invention is in the range of 0.5 to 0.9 μm.

Definition the average particle diameter D _50, determined as a whole by 100% cumulative curve of the measured value of the particle size of the abrasive particles (integral curve), the particle diameter when the cumulative curve becomes 50% and the average particle diameter D ₅₀ To do.

As a method of obtaining the particle diameter, a method of measuring 200 particle diameters using the above SEM (scanning electron microscope) and obtaining a frequency distribution can be used. In addition, it can be obtained by using a dynamic light scattering method, a laser diffraction method, a centrifugal sedimentation method, an FFF method (field flow fraction method), an electrical detector method, or the like.

Furthermore, the abrasive particles according to the present invention have a cerium content of 90 mol% or more, and contain at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Spherical abrasive particles having an amount of 10 mol% or less are preferred.
This suppresses the content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained together with cerium, thereby maintaining the production cost while maintaining the spherical shape. Can be suppressed.

The abrasive particles according to the present invention are characterized by having a spherical shape with a cerium content in the range of 95 to 100 mol%.
An abrasive containing spherical abrasive particles having a cerium content in the range of 95 to 100 mol% has a high cerium content, so that a high polishing rate can be obtained.
Here, the polishing speed is determined by supplying the abrasive slurry in which the abrasive powder containing the abrasive particles is dispersed in a solvent such as water to the surface to be polished of the polishing machine while the surface to be polished is polished with a polishing cloth. It can be measured by polishing.
The polishing rate can be measured by, for example, circulating the abrasive slurry to a polishing machine and performing polishing. The thickness before and after polishing is measured by Nikon Digimicro (MF501), and the polishing amount (μm) per minute can be calculated from the thickness displacement to obtain the polishing rate.

Moreover, it is preferable that the monodispersity of the particle diameter of the abrasive particles according to the present invention is 20.0% or less.
An abrasive containing abrasive particles exhibiting a high degree of monodispersity is less susceptible to scratches and is suitable for precision polishing.
Here, the occurrence of scratches can be determined by evaluating the surface state of the glass substrate.
For example, with respect to the surface state (surface roughness Ra) of the glass substrate surface, the surface roughness of a glass substrate that has been polished for 30 minutes is evaluated with a light wave interference type surface roughness meter (Dual-channel ZeMapper manufactured by Zygo). be able to. Ra represents the arithmetic average roughness in JIS B0601-2001.

(Content of fluorine element in abrasive particles)
The abrasive particles according to the present invention are characterized in that no fluorine element is mixed therein. In the present invention, the term “no fluorine element” means that the average content (mol%) of the fluorine element is 1.0 mol% or less, preferably 0.1 mol% or less, among the elements constituting the abrasive particles. It is.

In the present invention, as a method for measuring the fluorine element content in the abrasive particles, for example, 1 g of abrasive particles is dissolved in a mixed solution of 10 ml of nitric acid aqueous solution and 1.0 ml of hydrogen peroxide solution, and SII Nanotechnology Inc. Elemental analysis was performed using an ICP emission spectral plasma apparatus (ICP-AES). The average value of the content of fluorine element in the abrasive particles was determined as the composition ratio (mol%).

(Crystallite diameter)
In the abrasive particles according to the present invention, the average crystallite diameter is preferably in the range of 420 to 500 mm.

The “crystallite” according to the present invention refers to the largest region of microcrystals present as a complete single crystal in a polycrystalline particle. Specifically, as shown in FIG. 3, the abrasive particle 1 according to the present invention is formed of a plurality of crystallites 2. Since the growth rate of the crystallite 2 varies depending on the firing temperature and time, in the present invention, for example, by firing within a range of 1050 to 1500 ° C., an average crystallite diameter A suitable as an abrasive is 420. It is considered that an abrasive containing abrasive particles 1 in the range of ˜500 mm can be obtained. 3 shown in FIG. 3 is the particle diameter of the abrasive particles 1.

Generally, the obtained average crystallite diameter A represents the size of a crystal growing in the same direction in a crystal grain. The fact that the average crystallite diameter A is small means that the crystallite 2 growing in the same specific direction in the crystal grain is small. On the other hand, since the crystallite 2 grows by baking at an appropriate baking temperature for an appropriate time, crystal grains having a large average crystallite diameter A can be formed.

Therefore, when the crystallite diameter A is large, the growth in the same direction is large and the abrasive particles 1 become hard. In addition, when the crystallite diameter A is small, the growth in the same direction is small and the abrasive particles 1 are soft.

The average crystallite diameter A according to the present invention can be calculated by the XRD (X-ray diffraction) measurement using the Scherrer equation shown below.
A = Kλ / βcosθ
In the above equation, K is the Scherrer constant and λ is the X-ray wavelength. β is the half width of the diffraction line. θ is the Bragg angle with respect to the diffraction line.

FIG. 4 shows a scanning electron micrograph of cerium oxide particles having crystallites according to the present invention.

There is no limitation on the means for setting the average crystallite diameter A according to the present invention within the range of 420 to 500 mm, but in particular, it is preferable to control the firing temperature in the range of 1050 to 1500 ° C. in particular. It is.

In the abrasive particles according to the present invention, by setting the average crystallite diameter within the range of 420 to 500 mm, the initial high polishing rate can be maintained even when continuous polishing is performed.

<Method for Producing Abrasive Material Containing Abrasive Particles>
The preferred abrasive production methods 1 to 4 are shown below.

<< Abrasive Material Production Method 1 >>
In the abrasive production method of the present invention, the abrasive particles contained in the abrasive are produced by firing an abrasive particle precursor containing at least cerium oxide as a main component, and the firing treatment is performed at a firing temperature. Is preferably a step of treating within a range of 1050 to 1500 ° C.

In the present invention, the abrasive particles are preferably prepared by a wet synthesis method.
The wet synthesis method referred to in the present invention is a mixture of a rare earth aqueous solution containing cerium nitrate, cerium hydrochloride or cerium sulfate in a solution medium and an aqueous solution of a urea compound to prepare an abrasive particle precursor, followed by firing. This is a method of forming abrasive particles by treatment.

In the abrasive particle precursor referred to in the present invention, cerium oxide as a main component means that the content of cerium oxide is 55 mol% or more, preferably 81 mol% or more, more preferably 90 mol% or more. Especially preferably, it is 95 mol% or more.

The method for producing an abrasive according to the present invention is preferably prepared by a wet synthesis method. More specifically, as shown in FIG. 5, mainly, the abrasive particle precursor forming step (IA), A production method comprising a solid-liquid separation step (IB) and a firing step (IC) is preferred.

(1) Abrasive Particle Precursor Forming Step Abrasive particle precursor forming step that does not contain a fluorine compound is prepared by a wet synthesis method and contains Ce, or Ce and Y, La, without containing a fluorine compound. , Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and a part of the solution was previously thermally decomposed into an aqueous solution containing a salt with at least one element selected from Lu A urea compound is added, and said Ce or Ce and at least one element selected from Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; A dispersion solution is prepared in which a basic carbonate of the salt is dispersed. In addition, as the salt of Ce or Ce and at least one element selected from Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, nitrate is used. Hydrochloride, sulfate and the like can be used, and among them, nitrate is preferable.

Urea compounds such as urea, urea salts (eg, nitrates, hydrochlorides, etc.), N, N′-dimethylacetylurea, N, N′-dibenzoylurea, benzenesulfonylurea, p-toluenesulfonylurea, trimethyl Urea, tetraethylurea, tetramethylurea, triphenylurea, tetraphenylurea, N-benzoylurea, methylisourea, ethylisourea and the like can be mentioned, and urea is preferred. In addition, in the following examples, although it shows about the case where basic carbonate is formed using urea, it is an example and it is not limited to this.

In the formation of the precursor of abrasive particles, Ce or Ce and at least one selected from Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu The ion concentration in the aqueous solution of the salt with the element is preferably in the range of 0.001 to 0.1 mol / L, and urea is preferably in the range of 5 to 50 times the ion concentration. This is in an aqueous solution of the above-mentioned Ce or Ce and at least one element selected from Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. This is because it is possible to synthesize spherical abrasive particles exhibiting monodispersity by setting the ion concentration in and the ion concentration of urea within the ranges specified above.
The mixed aqueous solution is heated and stirred at 80 ° C. or higher to grow a basic carbonate dispersed in the aqueous solution. In the case of heating and stirring, the shape of the stirrer is not particularly specified if sufficient stirring efficiency can be obtained, but in order to obtain higher stirring efficiency, a rotor / stator type stirrer should be used. Is preferred.

In the abrasive particle according to the present invention, a high polishing rate can be obtained when the ratio (content ratio) of cerium oxide in the metal oxide composed of the above-described metal is 81 mol% or more. From the viewpoint of being able to.

(2) Solid-liquid separation step In the solid-liquid separation step, the formed abrasive particle precursor is subjected to solid-liquid separation from the dispersion solution containing the abrasive particle precursor obtained in (1) precursor particle forming step. It is a step of collecting abrasive particles to obtain an abrasive particle precursor.

As the solid-liquid separation method, a method of performing solid-liquid separation by natural sedimentation can be applied without applying forced separation means. For example, the dispersion solution containing the abrasive particle precursor is allowed to stand and separated into a supernatant liquid and an abrasive particle precursor precipitated at the bottom, and then the decantation method, for example, tilting the kettle to drain the supernatant liquid. Or a method of inserting the drainage pipe to the vicinity of the interface between the supernatant and concentrate in the separated pot and discharging only the supernatant to the outside of the pot to obtain an abrasive particle precursor. Can do. Alternatively, the abrasive particle precursor may be separated by solid-liquid separation using a filter or the like.

In the solid-liquid separation step, the obtained abrasive particle precursor may be washed with water and alcohol and dried and then transferred to the following (3) firing step.

(3) Firing step In the calcining step, the precursor of the basic carbonate abrasive particles obtained by solid-liquid separation is 400 ° C. or higher in the air or in an oxidizing atmosphere, and preferably 1050 to 1500 in the present invention. The calcination is carried out at a calcination temperature of 0 ° C. within a range of 1 to 5 hours. Since the precursor of the abrasive particles is desorbed with carbon dioxide when fired, the basic carbonate is converted to an oxide, and the desired average particle size in the range of 420 to 500 mm is obtained. It is done.

By subjecting the precursor of the abrasive particles to a firing treatment in the above temperature range and firing time range, an average crystallite diameter in the range of 420 to 500 mm capable of realizing a high polishing rate as an abrasive. It is considered that the abrasive particles possessed grow and the abrasive particles having sufficient hardness are obtained during polishing.

In the present invention, a specific firing apparatus for firing the precursor of the abrasive particles is preferably a known roller hearth kiln or rotary kiln. Thereby, heat is uniformly applied to the precursor of the abrasive particles, which is preferable from the viewpoint of obtaining abrasive particles having a uniform structure.

As a general roller hearth kiln, for example, a plurality of rollers are installed in the furnace, and the raw material is carried on the roller, so that the area in the furnace can be adjusted according to the temperature such as pre-baking, baking, cooling. it can. Moreover, as a general rotary kiln, for example, it is substantially cylindrical, and the raw material is gradually fed while slowly rotating in the kiln.

Moreover, after the solid-liquid separation process and before the baking process, temporary baking can also be performed. Specifically, the preliminary calcination is preferably performed within a range of a calcination temperature of 300 to 490 ° C. and a range of 1 to 5 hours. By pre-baking under the conditions, it is considered that an abrasive containing abrasive particles having sufficient crystallite growth and high durability against pressure during polishing can be obtained. In particular, it is preferable to perform preliminary firing within a range of 300 to 400 ° C. within a range of 2 to 3 hours from the viewpoint of sufficient crystallite growth.
In addition, also in temporary baking, a well-known roller hearth kiln or rotary kiln can be used similarly to a baking process.

Furthermore, it is preferable to raise the temperature in the firing step at a rate of temperature rise in the range of 20 to 50 ° C./min. Thereby, it is considered that crystallites containing a large amount of cerium grow stably.

Further, after the firing step, it is preferable to lower the temperature from 500 ° C. to room temperature (25 ° C.) at a temperature lowering rate within the range of 1 to 20 ° C./min. Thereby, it is considered that the generation of minute cracks in the abrasive particles can be suppressed, and it is possible to form abrasive particles that are strong against pressure during polishing and have few unevenness on the outermost surface.

<< Production Method 2 of Abrasive Material >>
The abrasive manufacturing method 2 generally comprises the following five steps (see FIG. 6).

1. Urea aqueous solution preparation process II-A
In the urea aqueous solution preparation step II-A, a urea aqueous solution having a predetermined concentration is prepared and heated in a sealed container to prepare a urea aqueous solution to be added.
For example, 0.5 L of a 5.0 mol / L urea aqueous solution is prepared (room temperature) (II-A1) and heated in a sealed container at 100 ° C. for 6 hours (II-A2, II-A3). Thereafter, a urea aqueous solution (II-A5) to which a urea aqueous solution (II-A4) cooled to 20 ° C. is added can be obtained.
By heating the aqueous urea solution in a sealed container, the hydrolysis can proceed while retaining the solvent. Thereby, in addition to the carbon dioxide and ammonia produced by the hydrolysis of urea, the three components of urea are dissolved in the urea aqueous solution.
Instead of urea aqueous solution, urea salt (eg, nitrate, hydrochloride, etc.), N, N′-dimethylacetylurea, N, N′-dibenzoylurea, benzenesulfonylurea, p-toluenesulfonylurea, trimethylurea Tetraethylurea, tetramethylurea, triphenylurea, tetraphenylurea, N-benzoylurea, methylisourea, ethylisourea and the like can also be used. In addition, in the following Examples, although it shows about the case where basic carbonate is formed using urea aqueous solution, it is an example and it is not limited to this.

2. Rare earth aqueous solution preparation process II-B
The rare earth aqueous solution preparation step II-B necessarily contains an aqueous solution or cerium having a cerium content of 95 to 100 mol%, and includes lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium, dysprosium, holmium, erbium, and thulium. An aqueous solution containing at least one element selected from ytterbium and lutetium is prepared.
An aqueous solution or cerium having a cerium content of 95 to 100 mol% is necessarily contained, and at least one selected from lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium The ion concentration in the aqueous solution containing the seed element is 0.001 mol / L to 0.1 mol / L, and urea is preferably 5 to 50 times the ion concentration.
This is cerium alone or in an aqueous solution of at least one element selected from lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. This is because it is considered that the spherical abrasive particles exhibiting monodispersity can be synthesized by setting the ion concentration in and the ion concentration of urea within the above ranges.
As salts of these elements that can be used for preparing the aqueous solution, nitrates, hydrochlorides, sulfates and the like can be used, but it is preferable to use nitrates. Thereby, an abrasive with few impurities can be manufactured.

3. Addition of urea aqueous solution and heating and stirring process II-C
The urea aqueous solution (II-A5) prepared in the urea aqueous solution preparation step II-A is heated in the rare earth aqueous solution (room temperature) (II-B1) in the rare earth aqueous solution preparation step II-B (II-B2) (II-B3) (II-C1). Then, the mixed solution is stirred while being heated (II-C2).
By mixing the urea aqueous solution and the rare earth aqueous solution, nuclei of abrasive particles are generated and dispersed in the mixed solution. By heating and stirring the mixed solution in which the nuclei of the abrasive particles are dispersed, the nuclei of the abrasive grow and the precursor of the abrasive particles is obtained.
Here, the addition of the urea aqueous solution is preferably performed at a higher addition rate. Specifically, the addition rate of the urea aqueous solution is preferably 0.5 mL / min or more, and particularly preferably 1.0 mL / min or more. By increasing the addition rate of the aqueous urea solution, it is considered that the nuclei of the abrasive particles generated by the aqueous urea solution can grow in a spherical shape without anisotropic growth.

The precursor of the abrasive particles is produced as a basic carbonate by reacting the rare earth aqueous solution and the urea aqueous solution (II-C3).
The heating temperature for heating is preferably 80 ° C. or higher, particularly preferably 90 ° C. or higher. The stirring time is preferably 1 hour or more and 10 hours or less, and particularly preferably 1 hour or more and 3 hours or less. In addition, heating temperature and stirring time can be suitably adjusted according to the target particle diameter.
Also, when sufficient stirring efficiency is obtained during heating and stirring, the shape of the stirrer is not specified, but in order to obtain higher stirring efficiency, a rotor / stator type stirrer should be used. Is preferred.

4). Solid-liquid separation process II-D
After heating and stirring, solid-liquid separation is performed to separate the generated precipitate (precursor of abrasive fine particles) from the solution. The solid-liquid separation method may be a general method. For example, a precursor of abrasive particles can be obtained by filtration using a filter or the like.

5. Firing step II-E
In the firing step II-E, the precursor of the abrasive particles obtained in the solid-liquid separation step II-D is fired at 400 ° C. or higher in air or in an oxidizing atmosphere. The precursor of the baked abrasive particle becomes an oxide and becomes an abrasive particle containing cerium oxide.
In addition, you may bake, after washing | cleaning and drying with water or alcohol before baking as needed.
By cooling after firing, the abrasive particles can be stabilized and then recovered as an abrasive containing the abrasive particles.
By producing an abrasive using the abrasive production method, an abrasive containing spherical abrasive particles that hardly contains anisotropically grown abrasive particles can be obtained.
The abrasive of the present invention contains 50% by mass or more of the abrasive particles, preferably 70% by mass or more, and particularly preferably 90% by mass or more. Thereby, the abrasive | polishing material with the small surface roughness by grinding | polishing can be obtained.

<< Abrasive Material Production Method 3 >>
The abrasive production method 3 is shown below.
The method for producing the abrasive preferably includes at least the following steps 1 to 5 and introduces carbon dioxide gas continuously or intermittently into the following aqueous solution or reaction solution at least during the following steps 2 to 3. .
Step 1: Step of preparing and heating an aqueous solution containing cerium (Ce) Step 2: Step of preparing a reaction solution by adding a precipitant to the aqueous solution heated in Step 1 Step 3: Heating the reaction solution Step of stirring to generate abrasive particle precursor Step 4: Separating the abrasive particle precursor generated in Step 3 from the reaction solution Step 5: The abrasive particle obtained by separating in Step 4 A step of firing the precursor in an oxidizing atmosphere to form abrasive particles

The method for producing an abrasive of the present invention generally comprises the following five steps 1 (III-A) to 5 (III-E) (see FIG. 7). Carbon dioxide gas (III-C1) may be introduced continuously or intermittently from step 1 (III-A) to step 4 (III-D), and at least step 2 (III-B) It is characterized in that it is introduced for up to Step 3 (III-C).
By introducing carbon dioxide gas continuously or intermittently into the aqueous solution or reaction solution, the carbonate ion concentration can be controlled within a desired range.
Here, “continuous” means introducing carbon dioxide into the reaction solution at a constant flow rate and pressure from the start to the end.
On the other hand, intermittent means that the introduction of carbon dioxide gas is introduced into the reaction solution at a predetermined flow rate and pressure from the start to the end. In addition, the said space | interval can be suitably set according to a flow volume and a pressure.
Specifically, it is sufficient that the carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in Step 2 (III-B) is in the range of 50 to 1600 mg / L. An amount of carbon dioxide gas can be introduced, which is preferable in that the supply amount of carbon dioxide gas can be controlled.

Further, it is more prominent that the carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in Step 2 (III-B) is in the range of 58 to 1569 mg / L. This is preferable.

1. Step 1 (rare earth aqueous solution preparation step III-A)
In step 1 (rare earth aqueous solution preparation step III-A), an aqueous solution (III-A1) containing cerium (Ce) is prepared and heated (III-A2) to obtain a rare earth aqueous solution (III-A3) at 90 ° C. .
Specifically, first, an aqueous solution containing cerium is prepared.
For example, an aqueous solution or cerium in which the cerium content is 95 to 100 mol% with respect to the total amount of rare earth elements contained in the aqueous solution, and lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium An aqueous solution containing at least one element selected from 14 kinds of rare earth elements consisting of dysprosium, holmium, erbium, thulium, ytterbium and lutetium is prepared.

The aqueous solution prepared by the step 1 (rare earth aqueous solution preparation step III-A) satisfies the following requirements 1a to 3a in that it can produce spherical abrasive particles with a high polishing rate and less scratches. preferable.
Requirement 1a: In addition to cerium, the aqueous solution is selected from the 14 rare earth elements consisting of lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Contains at least one element selected.
Requirement 2a: The total content of cerium contained in the aqueous solution and at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium contained in the aqueous solution is contained in the aqueous solution. It is 81 mol% or more with respect to the whole quantity of rare earth elements.
Requirement 3a: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the whole of the rare earth elements contained in the aqueous solution It is 19 mol% or less with respect to quantity.

In addition, the aqueous solution prepared by Step 1 (rare earth aqueous solution preparation step III-A) satisfies the following requirements 1b to 3b, so that spherical abrasive particles having a high cerium content and excellent polishing performance are obtained. It is preferable in that it can be manufactured.
Requirement 1b: In addition to the cerium, the aqueous solution contains at least one element selected from nine kinds of rare earth elements consisting of yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. .
Requirement 2b: The content of cerium in the aqueous solution is 81 mol% or more with respect to the total amount of rare earth elements contained in the aqueous solution.
Requirement 3b: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the entire rare earth element contained in the aqueous solution It is 19 mol% or less with respect to quantity.

In addition, the aqueous solution prepared in Step 1 (rare earth aqueous solution preparation step III-A) satisfies the following requirements 1c to 3c, and has a spherical content with a higher cerium content and better polishing performance. It is preferable at the point which can produce particle | grains.
Requirement 1c: In addition to the cerium, the aqueous solution contains at least one element selected from nine kinds of rare earth elements consisting of yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. .
Requirement 2c: The content of cerium in the aqueous solution is 90 mol% or more with respect to the total amount of rare earth elements contained in the aqueous solution.
Requirement 3c: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the whole of the rare earth elements contained in the aqueous solution It is 10 mol% or less with respect to the quantity.

Furthermore, the cerium content of the aqueous solution should be within the range of 95 to 100 mol% with respect to the total amount of rare earth elements contained in the aqueous solution, and the cerium content should be high and other elements should not be included. Therefore, it is preferable in that the abrasive can be produced with a small number of production steps.

In addition, the cerium content always includes an aqueous solution or cerium that is 95 to 100 mol% with respect to the total amount of rare earth elements contained in the aqueous solution, and includes lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium. The ion concentration in the aqueous solution containing at least one element selected from dysprosium, holmium, erbium, thulium, ytterbium and lutetium is 0.001 mol / L to 0.1 mol / L, and urea has the above ion concentration. A concentration of 5 to 50 times is preferable.
This is cerium alone or in an aqueous solution of at least one element selected from lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. This is because it is considered that the spherical abrasive particles exhibiting monodispersity can be synthesized by setting the ion concentration in and the ion concentration of urea within the above ranges.
As salts of these elements that can be used for preparing the aqueous solution, nitrates, hydrochlorides, sulfates and the like can be used, but it is preferable to use nitrates. Thereby, an abrasive with few impurities can be manufactured.

2. Step 2 (Precipitating agent addition step III-B)
In step 2 (precipitating agent adding step III-B), a precipitating agent (III-B3) is added to the aqueous solution (III-A3) heated in step 1 (III-A) to prepare a reaction solution.
The precipitating agent is preferably urea or a urea-based compound in that carbon dioxide and ammonia can be supplied by a hydrolysis reaction.
Specifically, in step 2 (precipitating agent adding step III-B), for example, a urea aqueous solution having a predetermined concentration is prepared in advance at room temperature (III-B1), and the urea aqueous solution is heated (III-B2). Added.
For example, 0.5 L of a 5.0 mol / L urea aqueous solution is prepared and heated to 60 ° C. (III-B3).
By heating at 60 ° C. or lower, urea can be maintained without hydrolysis, and the reaction proceeds without drastically reducing the temperature of the reaction liquid when added to the heated aqueous solution in Step 1. be able to.

Instead of urea aqueous solution, urea salt (eg, nitrate, hydrochloride, etc.), N, N′-dimethylacetylurea, N, N′-dibenzoylurea, benzenesulfonylurea, p-toluenesulfonylurea, trimethylurea An aqueous solution prepared from a urea-based compound such as tetraethylurea, tetramethylurea, triphenylurea, tetraphenylurea, N-benzoylurea, methylisourea, ethylisourea, ammonium hydrogencarbonate, or the like can also be used. In addition, in the following Examples, although it shows about the case where basic carbonate is formed using urea aqueous solution, it is an example and it is not limited to this.
Here, the addition of the urea aqueous solution is preferably performed at a higher addition rate. Specifically, the addition rate of the urea aqueous solution is preferably 0.5 L / min or more, and particularly preferably 1.0 L / min or more. By increasing the addition rate of the aqueous urea solution, it is considered that the nuclei of the abrasive particles generated by the aqueous urea solution can grow in a spherical shape without anisotropic growth.

3. Step 3 (Abrasive Particle Precursor Generation Step III-C)
In Step 3 (Abrasive Particle Precursor Generation Step III-C), the reaction liquid is heated and stirred (III-C2) to generate an abrasive particle precursor.
Specifically, the mixed solution is stirred while being heated.
By mixing the urea aqueous solution and the rare earth aqueous solution, nuclei of abrasive particles are generated and dispersed in the mixed solution. By heating and stirring the mixed solution in which the nuclei of the abrasive particles are dispersed, the nuclei of the abrasive grow and the precursor of the abrasive particles is obtained.

The precursor of the abrasive particles is produced as a basic carbonate by reacting a rare earth aqueous solution and a urea aqueous solution (III-C3).
The heating temperature for heating is preferably 80 ° C. or higher, particularly preferably 90 ° C. or higher. The stirring time is preferably 1 hour or more and 10 hours or less, and particularly preferably 1 hour or more and 3 hours or less. In addition, heating temperature and stirring time can be suitably adjusted according to the target particle diameter.
In addition, during heating and stirring (III-C2), if sufficient stirring efficiency can be obtained, the shape of the stirrer is not particularly specified, but in order to obtain higher stirring efficiency, a rotor / stator type stirring is performed. It is preferable to use a machine.

4). Step 4 (Solid-liquid separation step III-D)
In step 4 (solid-liquid separation step III-D), after stirring with heating, a solid-liquid separation operation is performed to separate the produced precipitate (precursor of abrasive fine particles) from the reaction solution. The method of solid-liquid separation operation may be a general method. For example, a precursor of abrasive particles can be obtained by filtration using a filter or the like.

5. Step 5 (Firing Step III-E)
In step 5 (firing step III-E), the precursor of the abrasive particles obtained in step 4 (solid-liquid separation step III-D) is fired at 400 ° C. or higher in an oxidizing atmosphere. The precursor of the baked abrasive particle becomes an oxide and becomes an abrasive particle containing cerium oxide.
In addition, you may bake, after washing | cleaning and drying with water or alcohol before baking as needed.
By cooling after firing, the abrasive particles can be stabilized and then recovered as an abrasive containing the abrasive particles.
By producing an abrasive using the abrasive production method, an abrasive containing spherical abrasive particles that hardly contains anisotropically grown abrasive particles can be obtained.
The abrasive of the present invention contains 50% by mass or more of the abrasive particles, preferably 70% by mass or more, and particularly preferably 90% by mass or more. Thereby, the abrasive | polishing material with the small surface roughness by grinding | polishing can be obtained.

<< Abrasive Material Production Method 4 >>
The method for producing spherical abrasive particles of the present invention is a method for producing spherical abrasive particles containing cerium oxide,
Adding an aqueous urea solution to an aqueous solution of a rare earth element-containing compound containing cerium to form abrasive precursor particles;
Adding at least a step of firing the abrasive precursor particles, and adding an aqueous urea solution that is thermally decomposed in the nucleation process of the particles in the initial stage of the reaction in the step of forming the abrasive precursor particles,
In the grain growth process after the nucleation process, a urea aqueous solution or a thermally decomposed urea aqueous solution is added.

The present invention is a chemical mechanical polishing method for polishing semiconductor devices and glass, in which polishing is performed by both physical action and chemical action in order to obtain a sufficient polishing rate while maintaining flatness with high accuracy. This is a method for producing spherical abrasive particles containing cerium oxide capable of being subjected to CMP (Chemical Mechanical Polishing).

In the present invention, the spherical abrasive particles are obtained by firing the abrasive precursor particles generated in the reaction liquid by mixing and heating the rare earth salt aqueous solution and the urea aqueous solution. In the present invention, the reaction liquid refers to a liquid obtained by mixing a rare earth salt aqueous solution and a urea aqueous solution.

The method for producing spherical abrasive particles of the present invention includes a step of adding an aqueous urea solution in at least a rare earth salt aqueous solution to form abrasive precursor particles and a step of firing the abrasive precursor particles. The following five steps (1. Urea aqueous solution preparation step IV-A, 2. Rare earth salt aqueous solution preparation step IV-B, 3. Forming abrasive precursor particles IV-C, 4. Solid-liquid separation step IV -D, 5. The step IV-E of firing (see FIG. 8)) is preferable.

1. Urea aqueous solution preparation process IV-A
In the urea aqueous solution preparation step IV-A, a urea aqueous solution (IV-A1a) having a predetermined concentration is prepared or heated by being heated in a sealed container to add a thermally decomposed urea aqueous solution (decomposed urea aqueous solution). This is a step for preparing IV-A1b).
For example, by heating an aqueous urea solution in a hermetically sealed container, hydrolysis can proceed while retaining the solvent. Thereby, in addition to the carbon dioxide and ammonia produced by the hydrolysis of urea, the three components of urea are dissolved in the urea aqueous solution.
Carbon dioxide exists as carbonate ions in the solution and becomes a raw material for abrasive precursor particles, which are basic carbonates described later.
In the present invention, “thermally decomposed urea aqueous solution” refers to an aqueous urea solution containing carbonate ions as a result of hydrolysis of urea by heating.

Carbonate ions are preferably contained in the aqueous solution at a carbonate ion concentration of 2.5 to 50 mmol / L. More preferably, it is in the range of 10 to 30 mmol / L.
For example, 0.5 L of a 5.0 mol / L urea aqueous solution is prepared and heated in a sealed container at 100 ° C. for 6 hours. Then, it can be set as the urea aqueous solution which adds the urea aqueous solution cooled to 20 degreeC.
The degree of hydrolysis can be controlled by the temperature and time of heating in the sealed container.
In the present invention, such an aqueous solution in which ureas are hydrolyzed and contains carbonate ions is also referred to as “decomposed urea liquid”.

As ureas, in addition to urea, salts of urea (eg, nitrates, hydrochlorides, etc.), N, N′-dimethylacetylurea, N, N′-dibenzoylurea, benzenesulfonylurea, p-toluenesulfonylurea, Examples thereof include trimethylurea, tetraethylurea, tetramethylurea, triphenylurea, tetraphenylurea, N-benzoylurea, methylisourea, ethylisourea, ammonium carbonate, and ammonium bicarbonate. Of these, urea is preferred. In addition, in the following Examples, although it shows about the case where basic carbonate is formed using urea aqueous solution, it is an example and it is not limited to this.

The carbonate ion concentration in the decomposed urea solution is a value measured at room temperature (25 ° C.). The carbonate ion concentration can be measured by an ion chromatography method. For example, it can be measured using an ion chromatograph manufactured by DIONEX, DX500 or the like.

2. Rare earth salt aqueous solution preparation process IV-B
The rare earth salt aqueous solution preparation step IV-B is a step of preparing an aqueous solution of a rare earth element-containing compound containing cerium (rare earth salt aqueous solution). The aqueous rare earth salt solution (IV-B1) at room temperature is heated (IV-B2) to prepare a rare earth salt aqueous solution at 90 ° C. (IV-B3).

Specifically, the rare earth salt aqueous solution always contains cerium, and the total content of at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium is 81 mol% or more, and yttrium, gadolinium. It is preferable to prepare an aqueous solution having such a composition that the content of at least one element selected from terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium is 19 mol% or less.

Specifically, the rare earth salt aqueous solution always contains cerium, and the total content of at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium is 81 mol% or more based on the total rare earth elements. And an aqueous solution having a composition in which the content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium is 19 mol% or less with respect to the total rare earth elements Is preferred.

The ion concentration of these solutions in an aqueous solution is 0.001 to 50 mol / L, and ureas are preferably 5 to 50 times the ion concentration.

This is cerium alone or in an aqueous solution of at least one element selected from lanthanum, praseodymium, neodymium, samarium, europium, yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. This is because it is considered that spherical abrasive particles exhibiting monodispersity can be synthesized by setting the ion concentration in the above and the ion concentration of urea within the above range.

As salts of these elements that can be used for preparing the aqueous solution, nitrates, hydrochlorides, sulfates and the like can be used, but it is preferable to use nitrates. Thereby, an abrasive with few impurities can be manufactured.

3. Step IV-C for forming abrasive precursor particles
Step IV-C of forming abrasive precursor particles is a step of forming abrasive precursor particles by adding an aqueous urea solution or the like to an aqueous solution of a rare earth element-containing compound containing cerium (rare earth salt aqueous solution IV-B3). It is.

In the present invention, in the step IV-C of forming abrasive precursor particles, the aqueous urea solution decomposed in the nucleation step (IV-C1a) of the initial reaction particles is added to the rare earth salt solution, and the nucleation step ( In the grain growth process (IV-C1b) after IV-C1a), an aqueous urea solution or an aqueous urea solution decomposed by heat decomposition is added.

As a result of studying the relationship between the shape of spherical abrasive particles and particle growth, etc., the present inventor has developed a process for forming abrasive precursor particles as a nucleation step (IV-C1a) at the initial stage of reaction and a grown nucleus. In the nucleation process (IV-C1a), the thermally decomposed aqueous solution of ureas, which is the raw material of the abrasive precursor particles, is added to the rare earth salt aqueous solution. The inventors have found that it is important to form nuclei and grow them at an early stage of body particle formation in order to produce spherical abrasive particles having high sphericity and excellent monodispersibility.

Although the mechanism of action of the present invention is not clarified, when forming spherical abrasive precursor particles, a rare earth salt containing cerium is added at the beginning of the reaction with an aqueous urea solution in an amount necessary for nucleation. By adding to the aqueous solution, it is considered that core particles having a uniform particle size distribution are generated. It is considered that spherical abrasive precursor particles excellent in monodispersion can be obtained while maintaining the particle size distribution by subsequently adding the urea aqueous solution as a raw material.

(I) Nucleation process (IV-C1a)
In the nucleation process (IV-C1a), the decomposed urea solution (IV-A1a) is added to a heated rare earth salt aqueous solution capable of hydrolyzing ureas. Nucleation takes place in a short time by adding a decomposed urea solution containing a large amount of carbonate ions as a raw material in the particle nucleation process (IV-C1a) at the initial stage of the reaction for forming abrasive precursor particles. It can be performed. For this reason, it is considered that the particle size distribution of the produced nuclei can be made narrower than before, compared with the case where the abrasive precursor particles are formed by mixing a conventional rare earth salt aqueous solution and a decomposed urea solution and then heating the mixture. .

The size of the nucleus is preferably about 10 to 300 nm. It can be carried out by appropriately controlling the concentration of the rare earth salt aqueous solution and the decomposed urea solution, the reaction temperature, the degree of decomposition of the decomposed urea solution, the addition rate and the added amount of the decomposed urea solution. The formation of nuclei can be confirmed by the reaction solution becoming colored or cloudy from blue to white. When the particle size is small, it is observed in blue, and as it increases, it is observed in white.
The addition rate of the thermally decomposed urea aqueous solution added in the nucleation process (IV-C1a) is within a range of 0.01 to 50 mol per minute per 1 liter of the reaction solution in terms of the urea concentration before the thermal decomposition. It is preferable that More preferably, the addition rate is in the range of 0.10 to 30 mol.
The faster the rate of addition, the narrower the particle size distribution of the produced nuclei, but if it is too early, the produced nuclei will aggregate or the local concentration distribution will become larger, causing the nuclei to grow anisotropically, resulting in a nuclear particle size distribution. This is because may increase.
The addition time is preferably within 10 minutes. More preferably, it is within 5 minutes. More preferably, it is within 1 minute.

Further, the carbonate ion concentration of the thermally decomposed aqueous urea solution to be added is preferably in the range of 2.5 to 50 mmol / L.
The degree of decomposition of ureas in the decomposed urea liquid is preferably 0.5% or more. Furthermore, 3% or more is preferable.
The temperature of the reaction solution in which the rare earth salt aqueous solution and the decomposed urea solution are mixed is preferably a temperature at which ureas can be hydrolyzed. Specifically, the temperature of the reaction solution is in the range of 75 to 100 ° C., preferably 80 to 100 ° C., more preferably 90 to 100 ° C.

(Ii) Particle growth process (IV-C1b)
The particle growth process (IV-C1b) is a process for growing the core particles formed in the nucleation process (IV-C1a) into larger abrasive precursor particles. The grain growth process (IV-C1a) is performed after the nucleation process (IV-C1a). After completion of the addition of the decomposed urea aqueous solution (IV-A1a) added in the nucleation process (IV-C1a), the reaction solution turns blue to white or becomes cloudy, and then the urea aqueous solution or the thermally decomposed urea aqueous solution (IV The grain growth process is started by adding -A1b).

Specifically, after the addition of the decomposed urea aqueous solution (IV-A1a) is completed, after confirming that the reaction solution is colored or cloudy from blue to white, within about 10 minutes, the urea aqueous solution preparation step IV-A is performed. The urea aqueous solution prepared in step 1 or the thermally decomposed urea aqueous solution is added to the rare earth salt aqueous solution prepared in the rare earth salt aqueous solution preparation step IV-B. The mixed solution is stirred while heating. By mixing the urea aqueous solution and the rare earth salt aqueous solution, the core of the abrasive grows, and the precursor of the abrasive particles (rare earth basic carbonate) is obtained (IV-C2).

In the particle growth process (IV-C1b), it is not preferable to generate new nuclei because the particle size distribution of the abrasive precursor particles is increased.
The concentration of the aqueous urea solution added during the growth process is preferably in the range of 0.05 to 10 mol / L.
Further, the carbonate ion concentration of the thermally decomposed urea aqueous solution added during the particle growth process is in the range of 0.01 to 30 mol / L, so that the particle size distribution of the growing abrasive precursor particles is not increased. It is preferable from the viewpoint.

The temperature of the reaction solution in which the rare earth salt aqueous solution and the decomposed urea aqueous solution are mixed is preferably a temperature at which ureas can be hydrolyzed. Specifically, the temperature of the reaction solution is in the range of 75 to 100 ° C., preferably 80 to 100 ° C., more preferably 90 to 100 ° C.
The stirring time is preferably 1 hour or more and 10 hours or less, and particularly preferably 1 hour or more and 3 hours or less. In addition, heating temperature and stirring time can be suitably adjusted according to the target particle diameter.
In the case of heating and stirring in the step of forming abrasive precursor particles, the shape of the stirrer is not particularly specified as long as sufficient stirring efficiency is obtained, but in order to obtain higher stirring efficiency, the rotor It is preferable to use a stator type stirrer.

4). Solid-liquid separation process IV-D
After heating and stirring, solid-liquid separation is performed to separate the generated precipitate (precursor of abrasive fine particles) from the solution. The solid-liquid separation method may be a general method. For example, a precursor of abrasive particles can be obtained by filtration using a filter or the like.

5. Firing step IV-E
In the firing step IV-E (also referred to as firing step), the precursor of the abrasive particles obtained in the solid-liquid separation step IV-D is fired at 400 ° C. or higher in air or in an oxidizing atmosphere. The precursor of the baked abrasive particle becomes an oxide and becomes an abrasive particle containing cerium oxide.

In addition, before baking as needed, you may wash | clean and dry with water or alcohol etc., and you may bake.

By cooling after firing, the abrasive particles can be stabilized and then recovered as an abrasive containing the abrasive particles.

By producing an abrasive using the method for producing an abrasive, an abrasive containing spherical abrasive particles that hardly contains anisotropically grown abrasive particles can be obtained.

The abrasive containing spherical abrasive particles produced by the production method of the present invention contains 50% by mass or more of the spherical abrasive particles, preferably 70% by mass or more, and particularly 90% by mass or more. preferable. Thereby, the abrasive | polishing material with the small surface roughness by grinding | polishing can be obtained.

《How to use abrasives》
An example of a method for using the abrasive of the present invention will be described by taking a polishing process of a glass substrate as an example.

1. Preparation of Abrasive Slurry Powder of the abrasive of the present invention containing abrasive particles according to the present invention is added to a solvent such as water to prepare an abrasive slurry. By adding a dispersant or the like to the abrasive slurry, aggregation is prevented, and the slurry is constantly stirred using a stirrer or the like to maintain a dispersed state. The abrasive slurry is circulated and supplied to the polishing machine using a supply pump.

2. Polishing process The glass substrate is brought into contact with the upper and lower surface plates of the polishing machine to which the polishing pad (polishing cloth) is applied, and the pad and the glass are moved relative to each other under pressure while supplying the abrasive slurry to the contact surface. Thus, the glass substrate is polished.

3. Abrasive Degradation The abrasive is used under pressure as in the polishing step. For this reason, the abrasive particles contained in the abrasive gradually collapse and become finer as the polishing time elapses. Since miniaturization of the abrasive particles causes a decrease in the polishing rate, an abrasive particle having a small change in particle size distribution before and after polishing is desired.

The abrasive containing abrasive particles having an average crystallite diameter in the range of 420 to 500 mm and a monodispersity of 30% or less according to the present invention has smoothness and polishing uniformity due to its high polishing rate. In the rough polishing step (primary polishing step) in which the polishing rate is more important than the secondary polishing step in which the above is required, the characteristics can be sufficiently exhibited.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

[Example I-1]
<Preparation of abrasive>
<Preparation of abrasive 101>
(Step 1)
After preparing 0.5 L of 5.0 mol / L urea aqueous solution, this urea aqueous solution was transferred to a container, the container was sealed, and then heat treatment was performed at 100 ° C. for 6 hours to decompose urea at high temperature. Thereafter, the urea aqueous solution was cooled to 20 ° C. to suppress scattering of carbon dioxide gas generated by the decomposition, and the amount dissolved in the urea aqueous solution was increased.

(Step 2)
After mixing 140 mL of a 1.0 mol / L cerium nitrate aqueous solution and 60 mol / L of a 1.0 mol / L lanthanum nitrate aqueous solution, it is finished to 9.5 L with pure water, and a rare earth aqueous solution (cerium: lanthanum = 70 30 (atomic ratio)), and this rare earth aqueous solution was heated to 90 ° C.

(Step 3)
Transfer 9.5 L of this 90 ° C. rare earth aqueous solution to a mixing kettle equipped with an axial flow stirrer, add the 20 ° C. urea aqueous solution prepared in Step 1 and stir at 90 ° C. for 120 minutes while stirring. An abrasive particle precursor dispersion of basic carbonate was prepared.

(Step 4: Solid-liquid separation process)
The basic carbonate abrasive particle precursor was separated from the prepared basic carbonate abrasive particle precursor dispersion with a membrane filter.

(Step 5: Firing process)
Next, the separated basic carbonate abrasive precursor was subjected to a baking treatment at a temperature of 1050 ° C. for 1 hour using a commercially available roller hearth kiln, an average particle diameter of 1.3 μm, and a fluorine compound. An abrasive 101 containing abrasive particles 101 having an average content of cerium oxide of 70 mol% and an average content of lanthanum oxide of 30 mol% was prepared. The monodispersity of the abrasive particles contained in the abrasive 101 was 24% as a result of measurement by the method described below. Moreover, the content rate of the cerium oxide of the said composition which the abrasive | polishing material 101 contains was 100 mass%.

<Preparation of abrasives 102-108>
In the preparation of the abrasive 101, except that the firing temperature in the firing step of Step 5 was changed to the conditions shown in Table 1, abrasive particles 102 comprising 70 mol% cerium oxide and 30 mol% lanthanum oxide were used. Abrasive materials 102 to 108 containing ˜108 were prepared.

<Preparation of abrasives 109-111>
In the preparation of the abrasive 101, monodispersion was carried out by appropriately adjusting the addition rate, stirring efficiency, liquid temperature and formation time of the urea aqueous solution to the rare earth aqueous solution during the formation of the basic carbonate abrasive particle precursor in Step 3. Abrasive materials 109 to 111 having degrees of 18%, 35%, and 42%, respectively, were prepared.

<Preparation of abrasive 112>
According to the method described in Example 1 of paragraphs (0070) to (0078) of Japanese Patent No. 3949147, the fluorine content is 27% by mass with respect to the basic carbonate abrasive particle precursor dispersion. After adding hydrofluoric acid and allowing it to stand, it was washed with ion-exchanged water three times by a decantation method to prepare an abrasive (cerium oxide) fluoride precursor.

Next, the basic carbonate abrasive particle precursor used in the preparation of the abrasive 101 and the prepared abrasive (cerium oxide) fluoride precursor were mixed at a mass ratio of 76:24, and then Step 5 In this baking treatment step, the abrasive is subjected to a baking treatment at a temperature of 1050 ° C. for 1 hour, an average particle diameter is 1.3 μm, contains a fluorine compound, cerium oxide is 70 mol%, and lanthanum oxide is 30 mol%. An abrasive 112 containing particles 112 was prepared.

《Abrasive evaluation》
The following characteristic values were measured and evaluated for each of the prepared abrasives and the constituent abrasive particles.

[Confirmation of the presence or absence of elemental fluorine]
As a method for measuring the fluorine element content in the abrasive particles, 1 g of abrasive particles are dissolved in a mixed solution of 10 ml of aqueous nitric acid and 1.0 ml of hydrogen peroxide solution, and ICP emission spectral plasma manufactured by SII Nanotechnology Inc. Elemental analysis was performed using an instrument (ICP-AES). The average value of the content of fluorine element in the abrasive particles was determined as the composition ratio (mol%). If the fluorine element content was 1.1 mol% or more, it was judged as “present”, and if it was 1.0 mol% or less, it was judged as “absent”. In the abrasives of the present invention, the fluorine element content was 0.1 mol% or less.

[Measurement of cerium content in abrasive particles]
The cerium content in the abrasive particles is measured by dissolving 1 g of the obtained abrasive particles in a mixed solution of 10 ml of nitric acid aqueous solution and 1.0 ml of hydrogen peroxide solution, and an ICP emission spectral plasma apparatus manufactured by SII Nano Technology. Elemental analysis is performed using (ICP-AES) to determine the total number of rare earth elements such as cerium, lanthanum, and yttrium in the abrasive particles, and the ratio of cerium to the total number of rare earth elements (mol%) This was taken as the average cerium content (mol%) in the abrasive particles.

[Measurement of average crystallite size]
About the abrasive | polishing material particle which each abrasive | polishing material contains, the average crystallite diameter was measured using the powder X-ray-diffraction apparatus (the Rigaku company make, MiniFlexII). As the X-ray source, CuKα ray was used, and the average crystallite diameter was calculated by the following Scherrer equation using the main peak ((111) plane) of X-ray diffraction.
D = Kλ / βcos θ
In the above equation, K is the Scherrer constant and λ is the X-ray wavelength. β is the half width of the diffraction line. θ is the Bragg angle with respect to the diffraction line.

Measurement of the average particle diameter D ₅₀ of the abrasive particles]
About the abrasive particle which comprises each abrasive | polishing material, 100 particle diameters are measured using TEM (transmission electron microscope), and the whole measured value of the particle diameter of an abrasive particle is a 100% accumulation curve (integral curve). The particle diameter when the cumulative curve is 50% was determined, and this was defined as the average particle diameter D ₅₀ (μm). In addition, the particle diameter calculated | required the diameter of the circle | round | yen which has an area equal to the abrasive particle image image | photographed with TEM (transmission electron microscope) as the particle diameter of the abrasive particle.

(Measurement of monodispersity of abrasive)
The abrasive particles constituting each abrasive are photographed using a TEM (transmission electron microscope), and the diameter of a circle having the same area as the photographed abrasive particle image is defined as the particle diameter of the abrasive particles. In this method, the particle size of 200 randomly selected abrasive particles was measured, and the average value was obtained as the average particle size of the abrasive particles. The standard deviation was determined from the difference between the measured average particle size and the particle size of the individual abrasive particles.

Next, the monodispersity was determined from the measured average particle size and standard deviation according to the following formula.
Monodispersity (%) = (standard deviation of particle diameter of abrasive particles) / (average particle diameter of abrasive particles) × 100

[Evaluation of polishing rate and polishing rate sustainability]
The polishing machine used for the evaluation of the polishing rate is a method of polishing the polishing target surface with a polishing cloth while supplying the polishing slurry prepared by dispersing the polishing material containing abrasive particles in a solvent to the polishing target surface. A polishing machine was used.

The abrasive slurry was prepared by dispersing abrasive particles as a dispersion medium using only water, and the particle concentration was 100 g / L.

The polishing rate was measured by circulating and supplying abrasive slurry at a flow rate of 10 L / min. A 65 mmφ glass substrate was used as the object to be polished, and a polishing cloth made of polyurethane was used as the polishing cloth. The polishing pressure on the polishing surface was 9.8 kPa (100 g / cm ² ), the rotation speed of the polishing tester was set to 50 min ⁻¹ (rpm), and polishing was performed for 30 minutes.

Next, the thickness of the glass substrate before polishing and after polishing for 30 minutes was measured using Nikon Digimicro (MF501), and the polishing amount (μm) per minute was calculated from the thickness displacement. The polishing rate was 1 (μm / min).

Next, the polishing operation for 30 minutes was repeated 10 times, and the polishing rate 2 (μm / min) in the 10th batch was measured.
Regarding the measured polishing rate 1 and polishing rate 2, the polishing rate was determined according to the following criteria. The polishing rate of the abrasive was determined by the rank of the polishing rate 1, and the polishing rate durability was evaluated by the change in the determination rank of the polishing rate 2 with respect to the polishing rate 1. The smaller the change in rank, the better the polishing rate durability. A rank of B or higher is a practically preferable range.

S: The polishing rate is 0.90 μm / min or more. A: The polishing rate is 0.70 μm / min or more and less than 0.90 μm / min. B: The polishing rate is 0.50 μm / min or more. Less than 70 μm / min C: Polishing rate is less than 0.50 μm / min Table 1 shows the results obtained as described above.

As apparent from the results shown in Table 1, the abrasives 101 to 107 of the present invention containing abrasive particles having an average crystallite diameter in the range of 420 to 500 mm and a monodispersity of 30% or less. Compared with the comparative example, it can be seen that the decrease rate of the polishing rate is small even after continuous polishing, and the dependency on the polishing rate is excellent.

On the other hand, the abrasive particles contained in the abrasive 108 as a comparative example have an average crystallite diameter that is equal to or less than the conditions specified in the present invention. As the process progressed, the abrasive particles cracked, and the number of particles contributing to the polishing rate decreased, resulting in poor polishing rate sustainability.

Further, the abrasive particles contained in the abrasive 109 as a comparative example have a size that exceeds the conditions specified by the present invention in the average crystallite diameter, become hard particles, and have high stability as particles, It is presumed that the chemical reactivity of this was weakened and the polishing rate was lowered.

In addition, the abrasives 110 and 111 containing abrasive particles having a monodispersity of more than 30% had a low polishing rate and a poor polishing rate sustainability.

Further, the polishing material 112 containing a fluorine compound in the polishing material also had a low polishing rate and inferior polishing rate sustainability.

[Example I-2]
<Preparation of abrasive>
<Preparation of abrasives 113 to 117>
In the preparation of the abrasive 102 described in Example I-1, the reaction time of the rare earth aqueous solution and the urea aqueous solution in Step 3 at 90 ° C. was appropriately shortened from 90 minutes, so that the average particle diameter D ₅₀ of the abrasive particles contained was reduced. Abrasive materials 113 to 117 were prepared in the same manner except that the conditions described in Table 2 (average particle diameter D ₅₀ = 0.3 to 1.1 μm) were changed.

《Abrasive evaluation》
For each of the above-prepared abrasives and the abrasive 102 prepared in Example I-1, the average crystallite diameter and average particle diameter D ₅₀ of the abrasive particles are the same as in the method described in Example I-1. Measurement, measurement of the monodispersity of the abrasive, evaluation of the polishing rate and polishing rate sustainability, and the results obtained are shown in Table 2.

As is clear from the results shown in Table 2, the number of abrasive particles contributing to polishing in the polishing step is increased by setting the range of the average particle diameter D ₅₀ within the range of 0.5 to 0.9 μm. It can be seen that the polishing rate is higher than the initial level, and the polishing rate sustainability is also excellent.

In the mean particle diameter D abrasive 117 range is less than 0.5μm of _50, although the polishing rate is high in the initial stage of the polishing, with the progress of the polishing operation, it is the abrasive particle surface easily covered with polishing debris, A slight decrease was observed from the viewpoint of sustaining the polishing rate.

[Example I-3]
<Preparation of abrasive>
<Preparation of abrasives 118-120>
Abrasive materials 118 to 120 were prepared in the same manner as in the preparation of the abrasive material 114 described in Example I-2, except that the cerium oxide content in the abrasive particles was changed to the conditions described in Table 3. The lanthanum oxide content was adjusted as the cerium oxide content increased.

《Abrasive evaluation》
For each of the above-prepared abrasives and the abrasive 114 prepared in Example I-2, the polishing rate and polishing rate durability were evaluated in the same manner as described in Example I-1, and obtained. The results are shown in Table 3.

As is clear from the results shown in Table 3, with the increase in the cerium oxide content, the polishing by chemical action becomes dominant, and the formed abrasive particles are easily maintained in shape, and the polishing rate continuity is further improved. You can see that

Example II
Hereinafter, although an Example and a comparative example are given and the manufacturing method of an abrasive | polishing material is demonstrated concretely, this invention is not limited to these. The additive element 1 in Table 4 represents a rare earth element contained in the aqueous solution when another rare earth aqueous solution is added to the cerium nitrate aqueous solution, and the addition amount of the aqueous solution containing the element is the addition element 1 addition amount. Represent as Similarly, additive element 2 represents a rare earth element contained in an aqueous solution in the case of adding another kind of rare earth aqueous solution in addition to additive element 1, and the addition amount of the aqueous solution containing the element is the addition element 2 addition amount. Represent as
Also, among the abrasive manufacturing methods shown in FIG. 3, the synthesis method of the abrasive particles is the synthesis method of the embodiment in which the preheated urea aqueous solution is added to the preheated rare earth aqueous solution. The method. On the other hand, the synthesis method of the comparative example in which the urea aqueous solution and the rare earth aqueous solution are mixed and then heated is referred to as a synthesis method using “heated urea”.

<Abrasive 201: Example>
(1) 0.5 L of a 5.0 mol / L urea aqueous solution was prepared and heated at 100 ° C. for 6 hours in a sealed container. Thereafter, the urea aqueous solution was cooled to room temperature.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) The urea aqueous solution prepared in (1) was added to the cerium nitrate aqueous solution heated to 90 ° C. in (2) at an addition rate of 1 L / min.
(4) The mixture obtained by adding the urea aqueous solution to the cerium nitrate aqueous solution in (3) was heated and stirred at 90 ° C. for 2 hours.
(5) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in (4) was separated by a membrane filter.
(6) The precursor of abrasive particles separated in (5) was baked at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 202: Example>
(1) 0.5 L of a 5.0 mol / L urea aqueous solution was prepared and heated at 100 ° C. for 6 hours in a sealed container. Thereafter, the urea aqueous solution was cooled to room temperature.
(2) After mixing 180 mL of 1.0 mol / L cerium nitrate aqueous solution and 20 mL of 1.0 mol / L yttrium nitrate aqueous solution, pure water was added to make 9.5 L, and this mixed aqueous solution was heated to 90 ° C. .
(3) The urea aqueous solution prepared in (1) was added to the mixed aqueous solution heated to 90 ° C. in (2) at an addition rate of 1 L / min.
(4) A mixed solution obtained by adding an aqueous urea solution to the mixed aqueous solution prepared in (3) was stirred at 90 ° C. for 2 hours.
(5) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in (4) was separated by a membrane filter.
(6) The precursor of abrasive particles separated in (5) was baked at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasives 203-211: Examples>
Abrasive materials 203 to 211 are produced by mixing the yttrium nitrate aqueous solution mixed in (2) of the abrasive material 2 production method with gadolinium nitrate aqueous solution, terbium nitrate aqueous solution, dysprosium nitrate aqueous solution, holmium nitrate aqueous solution, erbium nitrate aqueous solution, respectively. An abrasive was obtained by the same procedure except that the aqueous solution was changed to a thulium nitrate aqueous solution, an ytterbium nitrate aqueous solution, a lutetium nitrate aqueous solution, or an yttrium chloride aqueous solution.

<Abrasive 212: Example>
The manufacturing method of the abrasive 212 is the same as the procedure (2) of the manufacturing method of the abrasive 202 except that 180 mL of a 1.0 mol / L cerium nitrate aqueous solution, 10 mL of a 1.0 mol / L yttrium nitrate aqueous solution, and 1.0 mol / L. A polishing material was obtained by the same procedure except that the mixture was mixed with 10 mL of L gadolinium nitrate aqueous solution.

<Abrasives 213 and 214: Examples>
The manufacturing method of the abrasives 213 and 214 is the same as the procedure (2) of the manufacturing method of the abrasive 202 by mixing 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution. A polishing material was obtained in the same manner except that it was changed or mixed with 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 38 mL of a 1.0 mol / L gadolinium nitrate aqueous solution.

<Abrasive 215: Example>
The manufacturing method of the abrasive 215 is the same as the procedure (2) of the manufacturing method of the abrasive 212 except that 162 mL of a 1.0 mol / L cerium nitrate aqueous solution, 20 mL of a 1.0 mol / L yttrium nitrate aqueous solution, and 1.0 mol / L. A polishing material was obtained by the same procedure except that the mixture was mixed with 18 mL of L gadolinium nitrate aqueous solution.

<Abrasive 216: Example>
(1) 0.5 L of a 5.0 mol / L urea aqueous solution was prepared and heated at 100 ° C. for 6 hours in a sealed container. Thereafter, the urea aqueous solution was cooled to room temperature.
(2) After mixing 140 mL of 1.0 mol / L cerium nitrate aqueous solution and 60 mL of 1.0 mol / L lanthanum nitrate aqueous solution, pure water was added to make 9.5 L, and this mixed aqueous solution was heated to 90 ° C.
(3) The urea aqueous solution prepared in (1) was added to the mixed aqueous solution heated to 90 ° C. in (2) at an addition rate of 1 L / min.
(4) A mixed solution obtained by adding an aqueous urea solution to the mixed aqueous solution prepared in (3) was stirred at 90 ° C. for 2 hours.
(5) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in (4) was separated by a membrane filter.
(6) The precursor of abrasive particles separated in (5) was baked at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasives 217 to 220: Examples>
The manufacturing method of the abrasives 217 to 220 is that the lanthanum nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 216 is changed to a praseodymium nitrate aqueous solution, a neodymium nitrate aqueous solution, a samarium nitrate aqueous solution, and a europium nitrate aqueous solution, respectively. The same procedure was followed to obtain an abrasive.

<Abrasive 221: Examples>
The manufacturing method of the abrasive 221 is that 60 mL of a 1.0 mol / L lanthanum nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 216 is replaced with 40 mL of 1.0 mol / L lanthanum nitrate aqueous solution and 1.0 mol / L of lanthanum nitrate aqueous solution. Except having changed to 20 mL of praseodymium nitrate aqueous solution, it prepared in the same procedure and obtained the abrasive | polishing material.

<Abrasive material 222: Example>
The manufacturing method of the abrasives 222 is 40 mL of a 1.0 mol / L lanthanum nitrate aqueous solution and 20 mL of a 1.0 mol / L praseodymium nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 221. A polishing material was obtained by the same procedure except that the aqueous solution was changed to 40 mL of lanthanum nitrate aqueous solution and 20 mL of 1.0 mol / L yttrium nitrate aqueous solution.

<Abrasive 223: Example>
The manufacturing method of the abrasive 223 is that 1.0 mL / L of the 1.0 mol / L lanthanum nitrate aqueous solution and 20 mL of the 1.0 mol / L yttrium nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 222 are changed to 1.0 mol / L. A polishing material was obtained by the same procedure except that the solution was changed to 22 mL of a lanthanum nitrate aqueous solution and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution.

<Abrasive 224: Example>
The manufacturing method of the abrasive 224 was prepared in the same procedure except that the addition rate of the aqueous urea solution added in (3) of the manufacturing method of the abrasive 201 was changed to 0.5 L / min. It was.

<Abrasive 225: Example>
The manufacturing method of the abrasive 225 was prepared in the same procedure except that the addition rate of the urea aqueous solution added in (3) of the manufacturing method of the abrasive 202 was changed to 0.5 L / min. It was.

<Abrasive 226: Example>
The manufacturing method of the abrasive 226 is prepared in the same procedure except that the addition rate of the urea aqueous solution added in (3) of the manufacturing method of the abrasive 213 is changed to 0.5 L / min. It was.

<Abrasive 227: Example>
The manufacturing method of the abrasive 227 was prepared in the same procedure except that the addition rate of the urea aqueous solution added in (3) of the manufacturing method of the abrasive 216 was changed to 0.5 L / min. It was.

<Abrasive 228: Example>
The manufacturing method of the abrasive 228 was prepared in the same procedure except that the addition rate of the urea aqueous solution added in (3) of the manufacturing method of the abrasive 222 was changed to 0.5 L / min. It was.

<Abrasive 229: Comparative Example>
(1) 1.0 L of 2.5 mol / L urea aqueous solution was prepared.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.0 L.
(3) The urea aqueous solution prepared in (1) was added to the cerium nitrate aqueous solution prepared in (2) and stirred for 10 minutes.
(4) The mixed solution stirred in (3) was heated to 90 ° C. and heated and stirred for 2 hours.
(5) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in (4) was separated by a membrane filter.
(6) The precursor of abrasive particles separated in (5) was baked at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive material 230: Comparative example>
The manufacturing method of the abrasive 230 is (2) of the manufacturing method of the abrasive 229. Instead of 200 mL of the 1.0 mol / L cerium nitrate aqueous solution, 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 1.0 mol / L After mixing with 38 mL of an aqueous solution of L yttrium nitrate, preparation was performed in the same procedure except that pure water was added to make 9.0 L to obtain an abrasive.

<Abrasive 231: Comparative Example>
The manufacturing method of the abrasive 231 is (2) of the manufacturing method of the abrasive 230, and 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution are mixed with 1.0 mol / L. A polishing material was obtained by the same procedure except that the solution was changed to 140 mL of a cerium nitrate aqueous solution and 60 mL of a 1.0 mol / L lanthanum nitrate aqueous solution.

<Abrasive 232: Comparative Example>
The manufacturing method of the abrasive 232 is (2) of the manufacturing method of the abrasive 230, and 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution are mixed with 1.0 mol / L. A polishing material was obtained in the same manner except that 140 mL of an aqueous cerium nitrate solution, 22 mL of a 1.0 mol / L lanthanum nitrate aqueous solution, and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution were used.

Table 4 shows the synthesis conditions of the abrasives 201 to 232 thus obtained.

<Evaluation of abrasive>
About the abrasives 201 to 232, the composition, shape, and polishing performance were evaluated according to the following methods.

1. Elemental Analysis 1 g of abrasive particles contained in the obtained abrasives 201 to 232 are dissolved in a mixed solution of 10 ml of nitric acid aqueous solution and 1.0 ml of hydrogen peroxide solution, and an ICP emission spectroscopic plasma device manufactured by SII Nano Technology Co., Ltd. Elemental analysis was performed using (ICP-AES). The average content of each rare earth element in the abrasive particles contained in the abrasive was determined as a composition ratio (mol%). The results are shown in Table 5.

2. Particle shape / aspect ratio For abrasive particles, a scanning micrograph (SEM image) was taken, 100 particles were randomly selected, and the major axis was a and the minor axis was b. The average value was obtained as the aspect ratio. In addition, when drawing a circumscribing rectangle for each particle (referred to as “the circumscribing rectangle”), the shortest short side of the circumscribed rectangle is the shortest length, and the longest long side is the length. Is the major axis.
When the aspect ratio is in the range of 1.00 to 1.15, more preferably in the range of 1.00 to 1.05, it is classified as a spherical shape. When it was outside the range of 1.00 to 1.15, it was classified as an indeterminate form.

3. Particle size variation coefficient (CV value)
The coefficient of variation (also referred to as “monodispersity”) of the particle size distribution was determined from a scanning micrograph (SEM image) of 100 abrasive particles, and the monodispersity was evaluated. The particle diameter is determined based on the area of the photographic image of each particle, and the equivalent particle diameter is determined as the particle diameter of each particle.
The particle size distribution variation coefficient was determined by the following formula.
Coefficient of variation (%) = (standard deviation of particle size distribution / average particle size) × 100

4). Polishing speed The polishing speed is determined by polishing the surface to be polished with a polishing cloth while supplying abrasive slurry in which abrasive powder using abrasive particles is dispersed in a solvent such as water to the surface to be polished of the polishing machine. Was measured. The abrasive slurry was passed through a filter having a pore size of 5 μm with a dispersion medium of only water and a concentration of 100 g / L. In the polishing test, polishing was performed by circulatingly supplying an abrasive slurry at a flow rate of 5 L / min. A 65 mmφ glass substrate was used as the object to be polished, and a polyurethane cloth was used as the polishing cloth. The polishing pressure on the polished surface was 9.8 kPa (100 g / cm ² ), the rotation speed of the polishing tester was set to 100 min ⁻¹ (rpm), and polishing was performed for 30 minutes. The thickness before and after polishing was measured with Nikon Digimicro (MF501), and the polishing amount per minute (μm) was calculated from the thickness displacement, and was used as the polishing rate.

5. Surface Roughness Regarding the surface condition (surface roughness Ra) of the glass substrate surface, a glass substrate that had been polished for 30 minutes in the measurement of “4. Polishing speed” was used as a light wave interference type surface roughness meter (manufactured by Zygo). Surface roughness was evaluated using a Dual-channel ZeMapper. Ra represents the arithmetic average roughness in JIS B0601-2001.

<Evaluation of abrasive shape and polishing performance>
The results obtained from the above evaluation are summarized in Table 6.

From Table 5, the composition ratio (mol%) of each rare earth element of the abrasive particles contained in each abrasive is a value corresponding to the concentration and amount of the aqueous solution mixed in the manufacturing process of each abrasive. I understood. Also, from Table 6, the abrasives of the examples in which the rare earth aqueous solution and the urea aqueous solution were mixed in advance after being heated in advance were mixed with the sphericity (particle shape / aspect ratio) rather than the comparative abrasive in which the aqueous solution was mixed and heated and stirred. Ratio) and particle diameter variation coefficient (CV value) were small, and it was found that the polishing rate was high. Moreover, it turned out that the surface roughness of the abrasive | polishing material of an Example is smaller than the abrasive | polishing material of a comparative example, and a damage | wound is hard to generate | occur | produce.

Example III
Hereinafter, although an Example and a comparative example are given and the manufacturing method of an abrasive | polishing material is demonstrated concretely, this invention is not limited to these. In the examples, the display of “part” or “%” is used, but “part by mass” or “% by mass” is expressed unless otherwise specified.
In addition, additive element 1 in Table 7 represents a rare earth element contained in the aqueous solution when another rare earth aqueous solution is added to the cerium nitrate aqueous solution, and the addition amount of the aqueous solution containing the element is the addition element 1 addition amount. Represent as
Similarly, additive element 2 represents a rare earth element contained in an aqueous solution in the case of adding another kind of rare earth aqueous solution in addition to additive element 1, and the addition amount of the aqueous solution containing the element is the addition element 2 addition amount. Represent as

In addition, as an introduction method of carbon dioxide gas shown in Table 7, an open system is an aqueous solution or an aqueous solution without sealing a container or the like continuously or intermittently at a predetermined pressure and flow rate for a certain period from the start to the end of carbon dioxide introduction. It refers to a method in which carbon dioxide gas is blown out and dissolved in the reaction solution. The closed system, on the other hand, blows and dissolves carbon dioxide as bubbles in an aqueous solution or reaction solution in a sealed container or the like continuously or intermittently at a predetermined pressure and flow rate for a certain period from the start to the end of carbon dioxide introduction. The method of letting you say.
In the abrasives 301 to 331, after heating the aqueous solution containing cerium, carbon dioxide gas is introduced while the reaction solution is heated and stirred, but this is an example, before the aqueous urea solution is heated. Carbon dioxide gas may be introduced, or carbon dioxide gas may be introduced before the aqueous solution containing cerium is heated.
Further, the carbonate ion concentration shown in Table 7 represents the carbonate ion concentration at 90 ° C. measured immediately before adding the urea aqueous solution in the preparation process of each abrasive. Specifically, the carbonate ion concentration in the liquid was measured by collecting the reaction liquid immediately before the addition of the urea aqueous solution and using an ion chromatograph DX500 manufactured by DIONEX.
The urea addition start time shown in Table 7 represents the time from the start of introduction of carbon dioxide gas into the aqueous solution or reaction solution until the urea aqueous solution is added.

<Abrasive 301: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 15 minutes after the start of the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) A solution obtained by adding an aqueous urea solution to an aqueous cerium nitrate solution in the above (4) (hereinafter referred to as reaction solution) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 302: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) After mixing 180 mL of 1.0 mol / L cerium nitrate aqueous solution and 20 mL of 1.0 mol / L yttrium nitrate aqueous solution, pure water was added to make 9.5 L, and this mixed aqueous solution was heated to 90 ° C. .
(3) Carbon dioxide was supplied to the mixed aqueous solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 15 minutes after the start of the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasives 303-311: Examples>
The manufacturing method of the abrasives 303 to 311 includes the aqueous solution of yttrium nitrate mixed in (2) of the manufacturing method of the abrasive 302, respectively, an aqueous solution of gadolinium nitrate, an aqueous solution of terbium nitrate, an aqueous solution of dysprosium nitrate, an aqueous solution of holmium nitrate, an aqueous solution of erbium nitrate, An abrasive was obtained by the same procedure except that the aqueous solution was changed to a thulium nitrate aqueous solution, an ytterbium nitrate aqueous solution, a lutetium nitrate aqueous solution, or an yttrium chloride aqueous solution.

<Abrasive material 312: Example>
The manufacturing method of the abrasive 312 is the same as the procedure (2) of the manufacturing method of the abrasive 302 except that 180 mL of a 1.0 mol / L cerium nitrate aqueous solution, 10 mL of a 1.0 mol / L yttrium nitrate aqueous solution, and 1.0 mol / L. A polishing material was obtained by the same procedure except that the mixture was mixed with 10 mL of L gadolinium nitrate aqueous solution.

<Abrasives 313 and 314: Examples>
The manufacturing method of the abrasives 313 and 314 is the same as the procedure (2) of the manufacturing method of the abrasive 302 by mixing 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution. A polishing material was obtained in the same manner except that it was changed or mixed with 162 mL of a 1.0 mol / L cerium nitrate aqueous solution and 38 mL of a 1.0 mol / L gadolinium nitrate aqueous solution.

<Abrasive 315: Example>
The manufacturing method of the abrasive 315 is the same as the procedure (2) of the manufacturing method of the abrasive 312, 162 mL of a 1.0 mol / L cerium nitrate aqueous solution, 20 mL of a 1.0 mol / L yttrium nitrate aqueous solution, and 1.0 mol / L. A polishing material was obtained by the same procedure except that the mixture was mixed with 18 mL of L gadolinium nitrate aqueous solution.

<Abrasive 316: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) After mixing 140 mL of 1.0 mol / L cerium nitrate aqueous solution and 60 mL of 1.0 mol / L lanthanum nitrate aqueous solution, pure water was added to make 9.5 L, and this mixed aqueous solution was heated to 90 ° C. .
(3) Carbon dioxide was supplied to the mixed aqueous solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 15 minutes after the start of the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasives 317 to 320: Examples>
The manufacturing method of the abrasives 317 to 320 was changed except that the lanthanum nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 316 was changed to a praseodymium nitrate aqueous solution, a neodymium nitrate aqueous solution, a samarium nitrate aqueous solution, and a europium nitrate aqueous solution, respectively. The same procedure was followed to obtain an abrasive.

<Abrasive 321: Examples>
The manufacturing method of the abrasive 321 is that 60 mL of a 1.0 mol / L lanthanum nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 316 is replaced by 40 mL of 1.0 mol / L lanthanum nitrate aqueous solution and 1.0 mol / L of lanthanum nitrate aqueous solution. Except having changed to 20 mL of praseodymium nitrate aqueous solution, it prepared in the same procedure and obtained the abrasive | polishing material.

<Abrasive 322: Example>
The manufacturing method of the abrasive 322 is obtained by adding 40 mL of a 1.0 mol / L lanthanum nitrate aqueous solution and 20 mL of a 1.0 mol / L praseodymium nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 321 to 1.0 mol / L. A polishing material was obtained by the same procedure except that the aqueous solution was changed to 40 mL of lanthanum nitrate aqueous solution and 20 mL of 1.0 mol / L yttrium nitrate aqueous solution.

<Abrasive 323: Example>
A manufacturing method of the abrasive 323 is obtained by adding 40 mL of 1.0 mol / L lanthanum nitrate aqueous solution and 20 mL of 1.0 mol / L yttrium nitrate aqueous solution mixed in (2) of the manufacturing method of the abrasive 322 to 1.0 mol / L. A polishing material was obtained by the same procedure except that the solution was changed to 22 mL of a lanthanum nitrate aqueous solution and 38 mL of a 1.0 mol / L yttrium nitrate aqueous solution.

<Abrasive 324: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) One minute after starting the supply of carbon dioxide gas in (3) above, the urea prepared in (1) above is heated to 90 ° C. in (3) above, and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 325: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 3 minutes after the start of the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 326: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) Five minutes after starting the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and the aqueous cerium nitrate solution supplied with carbon dioxide gas is added. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 327: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 30 minutes after the start of the supply of carbon dioxide gas in (3) above, the urea prepared in (1) above is heated to 90 ° C. in (3) above and is added to the cerium nitrate aqueous solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 328: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Using an autoclave, pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) Ten minutes after starting the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 329: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Using an autoclave, pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 20 minutes after the start of the supply of carbon dioxide gas in (3), the urea prepared in (1) above is heated to 90 ° C. in (3) and added to the aqueous cerium nitrate solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive material 330: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Using an autoclave, pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) Carbon dioxide was supplied to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) 30 minutes after the start of the supply of carbon dioxide gas in (3) above, the urea prepared in (1) above is heated to 90 ° C. in (3) above and is added to the cerium nitrate aqueous solution supplied with carbon dioxide gas. The aqueous solution was added at an addition rate of 1 L / min.
(5) The reaction solution in which the urea aqueous solution was added to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The abrasive particle precursor separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 331: Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) The cerium nitrate aqueous solution heated to 90 ° C. in the above (2) was alternately supplied and stopped for 2 minutes at a flow rate of 0.5 L / min and a supply pressure of 0.1 MPa.
(4) Fifteen minutes after the start of the supply of carbon dioxide gas in (3) above, the mixture is heated to 90 ° C. in (3), and prepared in (1) above to a cerium nitrate aqueous solution supplied with carbon dioxide gas. The urea aqueous solution was added at an addition rate of 1 L / min.
(5) The solution obtained by adding the urea aqueous solution to the cerium nitrate aqueous solution in (4) was heated and stirred at 90 ° C. for 2 hours.
(6) The precursor of the abrasive particle precipitated in the reaction liquid heated and stirred in the above (5) was separated with a membrane filter.
(7) The precursor of the abrasive particles separated in (6) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

<Abrasive 332: Comparative Example>
(1) 0.5 L of 5.0 mol / L urea aqueous solution was prepared and heated to 60 ° C.
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.5 L, and this aqueous solution was heated to 90 ° C.
(3) The aqueous urea solution prepared in (1) above was added to the aqueous cerium nitrate solution heated to 90 ° C. in (2) above at an addition rate of 1 L / min.
(4) The reaction solution obtained by adding the aqueous urea solution to the aqueous cerium nitrate solution in (3) above was heated and stirred at 90 ° C. for 2 hours.
(5) The precursor of the abrasive particles precipitated in the reaction liquid heated and stirred in the above (4) was separated by a membrane filter.
(6) The abrasive particle precursor separated in (5) was fired at 600 ° C. to obtain an abrasive containing abrasive particles.

Table 7 shows the synthesis conditions of the abrasives 301 to 332 obtained as described above.

<Evaluation of abrasive>
For the abrasives 301 to 332, the shape and polishing performance of the abrasive were evaluated according to the following method.

1. Particle shape / aspect ratio When an abrasive particle is photographed by scanning electron micrograph (SEM image), 100 particles are randomly selected and the major axis is a and the minor axis is b. The average value was obtained as the aspect ratio. In addition, when drawing a circumscribing rectangle for each particle (referred to as “the circumscribing rectangle”), the shortest short side of the circumscribed rectangle is the shortest length, and the longest long side is the length. Is the major axis.
When the aspect ratio is in the range of 1.00 to 1.15, more preferably in the range of 1.00 to 1.05, it is classified as a spherical shape. When it was outside the range of 1.00 to 1.15, it was classified as an indeterminate form.

2. Particle size variation coefficient (CV value)
The coefficient of variation (also referred to as “monodispersity”) of the particle size distribution was determined from a scanning electron micrograph (SEM image) of 100 abrasive particles, and the monodispersity was evaluated. The particle diameter is determined based on the area of the photographic image of each particle, and the equivalent particle diameter is determined as the particle diameter of each particle.
The particle size distribution variation coefficient was determined by the following formula.
Coefficient of variation (%) = (standard deviation of particle size distribution / average particle size) × 100

3. Polishing speed The polishing speed is determined by polishing the surface to be polished with a polishing cloth while supplying abrasive slurry in which abrasive powder using abrasive particles is dispersed in a solvent such as water to the surface to be polished of the polishing machine. Was measured. The abrasive slurry was passed through a filter having a pore size of 5 μm with a dispersion medium of only water and a concentration of 100 g / L. In the polishing test, polishing was performed by circulatingly supplying an abrasive slurry at a flow rate of 5 L / min. A 65 mmφ glass substrate was used as the object to be polished, and a polyurethane cloth was used as the polishing cloth. The polishing pressure on the polished surface was 9.8 kPa (100 g / cm ² ), the rotation speed of the polishing tester was set to 100 min ⁻¹ (rpm), and polishing was performed for 30 minutes. The thickness before and after polishing was measured with Nikon Digimicro (MF501), and the polishing amount per minute (μm) was calculated from the thickness displacement, and was used as the polishing rate.

4). Surface Roughness Regarding the surface condition (surface roughness Ra) of the glass substrate surface, a glass substrate that had been polished for 30 minutes in the measurement of “3. Polishing speed” was converted into a light wave interference type surface roughness meter (Zygo). Surface roughness was evaluated using a Dual-channel ZeMapper. Ra represents the arithmetic average roughness in JIS B0601-2001.

5. Scratches Further, regarding the surface state (number of scratches) on the surface of the glass substrate, the glass substrate was polished for 30 minutes using a light wave interference type surface roughness meter (Dual-channel ZeMapper manufactured by Zygo). The number of scratches was evaluated by measuring the unevenness.
Specifically, the surface of the glass substrate polished for 30 minutes was visually inspected for the presence of scratches in the range of 50 to 100 μm on five glass substrates using a Dual-channel ZeMapper manufactured by Zygo, The average number of occurrences per sheet was expressed.

<Evaluation of abrasive shape and polishing performance>
The results obtained from the above evaluation are summarized in Table 8.

As shown in Table 8, the abrasives 301 to 331 of the examples prepared by introducing carbon dioxide have a spherical particle shape, whereas the abrasives 332 of the comparative example prepared without introducing carbon dioxide are not suitable. It became a fixed form. In addition, it was found that the abrasive of the example in which carbon dioxide was introduced had a smaller particle diameter variation coefficient (CV value) and surface roughness and fewer scratches than the abrasive of the comparative example in which no carbon dioxide was introduced. . It was found that the polishing rate was almost proportional to the amount of cerium solution used for the production of the abrasive.

[Example IV]
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

<Preparation of aqueous ureas>
Urea aqueous solutions A1 to A5 that were not thermally decomposed and B1 to B5 urea aqueous solutions that were thermally decomposed were used for the production of the following abrasive particles.
(Preparation of aqueous urea solution A1)
Urea aqueous solution A1: 2.5 mol / L urea aqueous solution (preparation of urea aqueous solutions A2 to A5)
5 L each of urea aqueous solutions having concentrations shown in Table 10, that is, 0.05, 0.03, 10 and 13 mol / L, were prepared as aqueous urea solutions A2 to A5, respectively.

(Preparation of aqueous urea solution B1)
0.5 L of 10 mol / L urea aqueous solution was prepared, and it heated at 100 degreeC for 6 hours within the airtight container. Thereafter, the urea aqueous solution was cooled to room temperature (25 ° C.) to obtain a urea aqueous solution of B1. The carbonate ion concentration measured at room temperature (25 ° C.) was 12 mmol / L.
(Preparation of aqueous urea solution B3-5)
In the preparation of the urea aqueous solution B1, urea aqueous solutions B3 to 5 were prepared in the same manner except that the concentration of the urea aqueous solution was changed so that the concentration of the decomposed urea solution became the carbonate ion concentration shown in Table 10. The liquid was used.
(Preparation of aqueous urea solutions B6-9)
In the preparation of the urea aqueous solution B1, the urea aqueous solution was decomposed by changing the temperature of the urea and the heating time, and cooled to room temperature (25 ° C.) to prepare decomposed urea aqueous solutions B6-9. Table 10 shows the results of measuring the carbonate ion concentration at room temperature (25 ° C.). In addition, in preparation of urea aqueous solution B8 and B9, it heated and prepared at 140 degreeC using the pressure | voltage resistant container.
(Preparation of aqueous urea solution B10-13)
In the preparation of the urea aqueous solution B1, the decomposition concentration, time, and temperature are changed as shown in Table 1, the urea aqueous solution is decomposed, cooled to room temperature (25 ° C.), and the decomposition urea aqueous solutions B10 to 13 used in the growth process are prepared. Prepared. Table 9 shows the results of measuring the carbonate ion concentration at room temperature (25 ° C.).

Carbonate ion concentration was measured by ion chromatography. The measurement was performed using an ion chromatograph DX500 manufactured by DIONEX.

<Manufacture of abrasive particles 401>
Comparative abrasive particles 401 were produced by the following procedure.
(1) 1.0 L of a 2.5 mol / L urea aqueous solution was prepared (urea aqueous solution A1).
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.0 L.
(3) The cerium nitrate aqueous solution prepared in (2) above was heated to 90 ° C.
(4) The urea aqueous solution prepared in (1) was added to the cerium nitrate aqueous solution heated in (3) above, and the mixture was heated and stirred for 1 hour.
(5) The precursor of the abrasive particle precipitated in the mixed solution heated and stirred in the above (4) was separated by a membrane filter.
(6) The abrasive particle precursors separated in (5) above were fired at 600 ° C. to obtain abrasive particles 401.

<Manufacture of abrasive particles 402>
The abrasive particles 402 according to the present invention were manufactured by the following procedure.
(1) 0.5 L of 5.0 mol / L decomposition urea aqueous solution was prepared (urea aqueous solution B1).
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.0 L.
(3) The cerium nitrate aqueous solution prepared in (2) above was heated to 90 ° C.
(4) The decomposed urea aqueous solution prepared in (1) was added to the cerium nitrate aqueous solution heated in (3) above, and the mixture was heated and stirred for 10 minutes (nucleation process).
(5) 0.5 L of an aqueous urea solution having a concentration of 0.05 mol / L was added to the mixed solution of (4) above, and the mixture was stirred for 50 minutes by heating (growth process).
(6) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in the above (5) was separated with a membrane filter.
(7) The abrasive particle precursors separated in (6) above were fired at 600 ° C. to obtain abrasive particles 402.

<Production of abrasive particles 403 to 405>
In the production of the abrasive particles 402, the decomposed urea aqueous solution used in (1) was changed to B3 to B5 to produce abrasive particles 403 to 405.

<Production of abrasive particles 406 to 409>
In the production of the abrasive particles 402, the decomposed urea aqueous solution used in (1) was replaced with B6 to B9 to prepare abrasive particles 406 to 409.

<Production of abrasive particles 410 to 412>
(1) 0.5 L of 5.0 mol / L decomposition urea aqueous solution was prepared (urea aqueous solution B1).
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.0 L.
(3) The cerium nitrate aqueous solution prepared in (2) above was heated to 90 ° C.
(4) The decomposed urea aqueous solution prepared in (1) was added to the cerium nitrate aqueous solution heated in (3) above, and the mixture was heated and stirred for 10 minutes.
(5) 0.5 L of an aqueous urea solution (urea aqueous solution A3 to A5) having the concentration shown in Table 10 was added to the mixed solution of (4), and the mixture was heated and stirred for 50 minutes.
(6) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in the above (5) was separated with a membrane filter.
(7) The abrasive particle precursors separated in (6) above were fired at 600 ° C. to obtain abrasive particles 410 to 412.

<Production of abrasive particles 413 to 416>
(1) 0.5 L of 5.0 mol / L decomposition urea aqueous solution was prepared (urea aqueous solution B1).
(2) Pure water was added to 200 mL of a 1.0 mol / L cerium nitrate aqueous solution to make 9.0 L.
(3) The cerium nitrate aqueous solution prepared in (2) above was heated to 90 ° C.
(4) The decomposed urea aqueous solution prepared in (1) was added to the cerium nitrate aqueous solution heated in (3) above, and the mixture was heated and stirred for 10 minutes.
(5) 0.5 L of an aqueous urea solution (urea aqueous solutions B10 to B13) decomposed at the concentration, decomposition temperature, and time shown in Table 9 was added to the mixed solution of (4) above, and the mixture was heated and stirred for 50 minutes. .
(6) The precursor of the abrasive particles precipitated in the mixed solution heated and stirred in the above (5) was separated with a membrane filter.
(7) The abrasive particle precursors separated in (6) above were fired at 600 ° C. to obtain abrasive particles 413 to 416.

<Production of abrasive particles 417 to 425>
In the production of the abrasive particles 402, as shown in Table 9, the rare earth elements in the rare earth salt aqueous solution were replaced with the respective mol% nitrates shown in the table without changing the total amount, and the types of urea aqueous solutions Abrasive particles 417 to 425 were prepared by changing the addition rate, concentration thereof, and carbonate ion concentration as shown in Table 10.
In Table 10, the addition rate (mol) represents the number of moles of urea added per minute with respect to 1 L of the reaction solution.

<Evaluation of abrasive particles>
The composition, shape and polishing performance of the abrasive particles 401 to 425 were evaluated according to the following method.

1. Elemental Analysis 1 g of each of the obtained abrasive particles 401 to 425 was dissolved in a mixed solution of 10 ml of nitric acid aqueous solution and 1.0 ml of hydrogen peroxide solution, and ICP emission spectral plasma apparatus (ICP-AES) manufactured by SII Nanotechnology Inc. Was used for elemental analysis. The average content of each rare earth element in the abrasive particles contained in the abrasive was determined as a composition ratio (mol%). As a result, it was found that the values agreed with the prescription values shown in Table 10.

2. Particle shape / aspect ratio For abrasive particles, a scanning micrograph (SEM image) was taken, 100 particles were randomly selected, and the major axis was a and the minor axis was b. The average value was obtained as the aspect ratio. In addition, when drawing a circumscribing rectangle for each particle (referred to as “the circumscribing rectangle”), the shortest short side of the circumscribed rectangle is the shortest length, and the longest long side is the length. Is the major axis.

When the aspect ratio is in the range of 1.00 to 1.15, more preferably in the range of 1.00 to 1.05, it is classified as a spherical shape. When it was outside the range of 1.00 to 1.15, it was classified as an indeterminate form.

3. Particle size variation coefficient (CV value)
The coefficient of variation (also referred to as “monodispersity”) of the particle size distribution was determined from a scanning micrograph (SEM image) of 100 abrasive particles, and the monodispersity was evaluated. The particle diameter is determined based on the area of the photographic image of each particle, and the equivalent particle diameter is determined as the particle diameter of each particle. Moreover, the arithmetic average of the particle diameter of each particle was made into the average particle diameter.
The particle size distribution variation coefficient was determined by the following formula.
Coefficient of variation (%) = (standard deviation of particle size distribution / average particle size) × 100

<Evaluation of abrasive shape and polishing performance>
The results obtained from the above evaluation are summarized in Table 11.

From Table 11, the composition ratio (mol%) of each rare earth element of the abrasive particles contained in each abrasive is a value corresponding to the concentration and amount of the aqueous solution mixed in the manufacturing process of each abrasive. I understood. Further, from Table 10, the abrasive particles 402 to 425 according to the present invention manufactured through the nucleation process and the growth process have a sphericity (particle shape / aspect ratio) and particles as compared with the abrasive particles 401 of the comparative example. It was found that the diameter variation coefficient (CV value) was small and the polishing rate was fast. Moreover, it turned out that the surface roughness of the abrasive | polishing material of an Example is smaller than the abrasive | polishing material of a comparative example, and a damage | wound is hard to generate | occur | produce.

The present invention may be used in the field of polishing with an abrasive containing cerium oxide in the manufacturing process of glass products, semiconductor devices, crystal oscillators and the like.

DESCRIPTION OF SYMBOLS 1 Abrasive particle 2 Crystallite 3 Particle diameter A Average crystallite diameter IA Abrasive particle precursor formation process IB Solid-liquid separation process IC Firing process II-A Urea aqueous solution adjustment process II-A1 Urea aqueous solution ( room temperature)
II-A2 Heating II-A3 Urea aqueous solution (100 ° C)
II-A4 Cooling II-A5 Aqueous urea solution (20 ° C)
II-B Rare earth aqueous solution adjustment process II-B1 Rare earth aqueous solution (room temperature)
II-B2 Heating II-B3 Rare earth solution (90 ° C)
II-C Urea aqueous solution addition and heating and stirring process II-C1 Urea aqueous solution addition II-C2 Heating and stirring II-C3 Rare earth basic carbonate formation II-D Solid-liquid separation process II-E Firing process III-A Rare earth aqueous solution adjustment process III-A1 Rare earth aqueous solution (room temperature)
III-A2 Heating III-A3 Rare earth solution (90 ° C)
III-B Precipitant addition process III-B1 Urea aqueous solution (room temperature)
III-B2 Heating III-B3 Aqueous urea solution (60 ° C)
III-C Abrasive particle precursor generation process III-C1 Carbon dioxide introduction III-C2 Heating and stirring III-C3 Rare earth basic carbonate generation III-D Solid-liquid separation process III-E Firing process IV-A Urea aqueous solution adjustment process IV-A1a Decomposed urea aqueous solution (25 ° C)
IV-A1b Decomposed urea aqueous solution or decomposed urea aqueous solution (25 ° C)
IV-B Rare earth salt aqueous solution adjustment process IV-B1 Rare earth salt aqueous solution (25 ° C)
IV-B2 Heating IV-B3 Rare earth salt aqueous solution (90 ° C)
IV-C Process for forming abrasive precursor particles IV-C1 Heating and stirring IV-C1a Nucleation process IV-C1b Growth process IV-C2 Rare earth basic carbonate generation IV-D Solid-liquid separation process IV-E Firing process

Claims

Cerium (Ce),
With at least one element selected from lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm) and europium (Eu),
The total content is 81 mol% or more,
At least one selected from yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) Containing abrasive particles having an elemental content of 19 mol% or less,
An abrasive having a monodispersity of particle size of the abrasive particles of 30% or less.
2. The abrasive according to claim 1, wherein an average crystallite diameter of the abrasive particles is in a range of 420 to 500 mm.
The average particle diameter D 50, abrasive material according to claim 1 or claim 2, characterized in that in the range of 0.5 ~ 0.9 .mu.m of the abrasive particles.
The abrasive according to any one of claims 1 to 3, wherein an average content of the abrasive particles is 80% by mass or more of all abrasive particles.
The content of cerium (Ce) is 81 mol% or more,
At least one selected from yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) The abrasive according to any one of claims 1 to 4, wherein the abrasive contains particles of 19 mol% or less.
The content of cerium (Ce) is 90 mol% or more,
At least one selected from yttrium (Y), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) The abrasive according to any one of claims 1 to 5, wherein the abrasive contains particles having an element content of 10 mol% or less.
Containing abrasive particles in which the content of cerium (Ce) is in the range of 95 to 100 mol%,
An abrasive having a monodispersity of particle size of the abrasive particles of 30% or less.
The abrasive according to claim 7, wherein a monodispersity of the particle diameter of the abrasive particles is 20% or less.
A manufacturing method for manufacturing the abrasive according to any one of claims 1 to 8,
Contains abrasive particles characterized by including carbon dioxide gas continuously or intermittently into the following aqueous solution or reaction solution, including at least the following steps 1 to 5 and at least the following steps 2 to 3. A manufacturing method of an abrasive.
Step 1: Step of preparing and heating an aqueous solution containing cerium (Ce) Step 2: Step of preparing a reaction solution by adding a precipitant to the aqueous solution heated in Step 1 Step 3: Heating the reaction solution Step of stirring to generate abrasive particle precursor Step 4: Separating the abrasive particle precursor generated in Step 3 from the reaction solution Step 5: The abrasive particle obtained by separating in Step 4 A step of firing the precursor in an oxidizing atmosphere to form abrasive particles
The method for producing an abrasive containing abrasive particles according to claim 9, wherein the aqueous solution satisfies the following requirements 1a to 3a.
Requirement 1a: In addition to cerium, the aqueous solution contains lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), yttrium (Y), gadolinium (Gd), terbium ( At least one element selected from 14 rare earth elements consisting of Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) contains.
Requirement 2a: The total content of cerium contained in the aqueous solution and at least one element selected from lanthanum, praseodymium, neodymium, samarium and europium contained in the aqueous solution is contained in the aqueous solution. It is 81 mol% or more with respect to the whole quantity of rare earth elements.
Requirement 3a: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the whole of the rare earth elements contained in the aqueous solution It is 19 mol% or less with respect to quantity.
The method for producing an abrasive containing abrasive particles according to claim 10, wherein the aqueous solution satisfies the following requirements 1b to 3b.
Requirement 1b: In addition to the cerium, the aqueous solution contains at least one element selected from nine kinds of rare earth elements consisting of yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. .
Requirement 2b: The content of cerium in the aqueous solution is 81 mol% or more with respect to the total amount of rare earth elements contained in the aqueous solution.
Requirement 3b: The content of at least one element selected from yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium contained in the aqueous solution is the entire rare earth element contained in the aqueous solution It is 19 mol% or less with respect to quantity.
The abrasive particles according to claim 9, wherein the content of cerium in the aqueous solution is within a range of 95 to 100 mol% with respect to the total amount of rare earth elements contained in the aqueous solution. A manufacturing method of an abrasive.
The carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in the step 2 is in the range of 50 to 1600 mg / L. A method for producing an abrasive containing the abrasive particles according to claim 1.
The carbonate ion concentration in the aqueous solution or the reaction solution immediately before adding the precipitant in the step 2 is in the range of 58 to 1569 mg / L. A method for producing an abrasive containing the abrasive particles according to claim 1.
The method for producing an abrasive containing abrasive particles according to any one of claims 9 to 14, wherein the precipitant is urea or a urea-based compound.
A manufacturing method for manufacturing the abrasive according to any one of claims 1 to 8,
Adding an aqueous urea solution to an aqueous solution of a rare earth element-containing compound containing cerium to form abrasive precursor particles;
Adding at least a step of firing the abrasive precursor particles, and adding an aqueous urea solution that is thermally decomposed in the nucleation process of the particles in the initial stage of the reaction in the step of forming the abrasive precursor particles,
A method for producing an abrasive containing abrasive particles, wherein an aqueous urea solution or an aqueous urea solution decomposed by heat decomposition is added in a particle growth process after the nucleation process.
The addition rate of the thermally decomposed urea aqueous solution added in the nucleation process of the particles at the initial stage of the reaction is in the range of 0.01 to 50 mol per minute per 1 liter of the reaction solution in terms of the urea concentration before the thermal decomposition The manufacturing method of the abrasive | polishing material containing the abrasive | polishing material particle of Claim 16 characterized by the above-mentioned.
18. The carbonate ion concentration of the thermally decomposed aqueous urea solution added in the nucleation process of the particles at the initial stage of the reaction is in the range of 2.5 to 50 mmol / L. A method for producing an abrasive containing abrasive particles.
The abrasive according to any one of claims 16 to 18, wherein the concentration of the aqueous urea solution added in the particle growth process is in the range of 0.05 to 10 mol / L. A method for producing an abrasive containing particles.
20. The carbonate ion concentration of the thermally decomposed aqueous urea solution added during the particle growth process is in the range of 0.1 to 30 mmol / L. A method for producing an abrasive containing the abrasive particles according to Item.
A manufacturing method for manufacturing the abrasive according to any one of claims 1 to 4,
The abrasive particles contained in the abrasive are produced by firing an abrasive particle precursor containing at least cerium oxide as a main component, and the firing treatment is performed at a firing temperature of 1050 to 1500 ° C. A method for producing an abrasive material, characterized in that the method comprises:
The method for producing an abrasive according to claim 21, wherein the baking apparatus for baking the abrasive particle precursor in the baking step is a roller hearth kiln or a rotary kiln.
A polishing method, wherein the abrasive according to any one of claims 1 to 8 is used for polishing an object to be polished.