WO2016194614A1 - Polishing composition, polishing method, and production method - Google Patents

Abstract

This invention enables a high polishing speed in the polishing of ceramics that are used in electronic devices and include an oxide crystal, or the like, by suppressing the occurrence of defects such as scratches. A polishing composition that includes water and abrasive grains, and is characterized in that the abrasive grains include 71–83 mass%, relative to the total amount of the abrasive grains, of an abrasive grain having an average particle size of 10–45 nm, and 17–29 mass%, relative to the total amount of the abrasive grains, of an abrasive grain having an average particle size of 80–170 nm. The combined amount of the abrasive grain having an average particle size of 10–45 nm and the abrasive grain having an average particle size of 80–170 nm accounts for more than 90 mass% of the total amount of the abrasive grains.

Description

Polishing composition, polishing method, and production method

The present invention relates to a polishing composition used for polishing a polishing object containing a metal or metalloid oxide or a composite material thereof.

Ceramic products containing metal or metalloid oxides or composite materials thereof are widely used as various electronic devices, functional ceramics, hard materials and the like.
Conventionally, in order to polish the surface of a ceramic product made of such a hard and brittle material and perform mirror finishing or smoothing, a polishing composition containing diamond abrasive grains as disclosed in Patent Documents 1 and 2 is used. It is used to use. However, the polishing composition containing diamond abrasive grains is expensive and has a problem that it easily causes scratches and makes it difficult to obtain a high-quality mirror surface.
In Patent Documents 3 and 4, it is proposed to use a polishing composition using colloidal silica as abrasive grains. However, with a polishing composition using colloidal silica as abrasive grains, a sufficient polishing rate could not be obtained.

Japanese Patent Laid-Open No. 7-179848 JP 2008-290183 A JP 2008-44078 A Special Table 2003-52962

The object of the present invention is high in suppressing the occurrence of defects such as scratches in the polishing of ceramics including oxide crystals used for electronic devices and the like that require high-quality smooth surfaces and high-quality texture by mirror finish. The object is to provide a polishing composition capable of realizing a polishing rate at low cost.

The polishing composition according to one embodiment of the present invention is a polishing composition containing water and abrasive grains, and the abrasive grains are 71-83 in the whole abrasive grains with an average grain size of 10 nm to 45 nm. Abrasive grains containing 17 to 29 mass% of abrasive grains having an average particle diameter of 80 to 170 nm and an average grain diameter of 10 to 45 nm and abrasive grains having an average grain diameter of 80 to 170 nm. The total amount of grains may occupy 90% by mass or more of the total amount of abrasive grains.

The polishing composition according to another embodiment of the present invention is an abrasive having an average particle diameter of 80 to 170 nm with respect to the particle diameter A of the abrasive grain having the largest number among the abrasive grains having an average particle diameter of 10 to 45 nm. Among them, the ratio B / A of the particle diameter B of the abrasive grains having the largest number may be 2.5 or more.
In the polishing composition according to another embodiment of the present invention, the abrasive may be silica.
The polishing composition according to another embodiment of the present invention may have a pH of 5.0 to 10.0.

The polishing composition according to another embodiment of the present invention may be used for polishing the surface of an object to be polished containing one or more metal or metalloid oxides or composite materials thereof.
The polishing composition according to another embodiment of the present invention is an object to be polished containing one or more oxides of one or more metals or metalloids selected from Groups 3, 4, and 13, or a composite material thereof. It may be used to polish the surface of an object.

One embodiment of the present invention is a polishing method for polishing the surface of an object to be polished using the polishing composition of the above embodiment.
One embodiment of the present invention is a polishing method for polishing a surface of an object to be polished containing a metal or metalloid oxide or a composite material thereof using the polishing composition of the above embodiment.
Another embodiment of the present invention is a method for manufacturing a component including one or more metal or metalloid oxides or composite materials thereof using the polishing method of the above embodiment.

According to the polishing composition of the present invention, a high polishing rate can be realized in polishing an object to be polished.

Hereinafter, an embodiment of the present invention will be described.
In one embodiment of the present invention, the object to be polished is not particularly limited, and may include a plurality of metals, alloys, ceramics (oxides, carbides, nitrides, etc.). The object to be polished may be, for example, a metal or metalloid oxide or a composite material thereof. In particular, it may be an oxide of one or more metals or metalloids selected from Groups 3, 4 and 13 of the periodic table, or a composite material thereof, and further may be Group 4. The metal oxide is a metal or metalloid oxide or a composite oxide thereof, for example, one or more metal or metalloid oxides selected from elements of Groups 3, 4, and 13 of the periodic table Or these complex oxides are mentioned. Specific examples include silicon oxide (silica), aluminum oxide (alumina), titanium oxide (titania), zirconium oxide (zirconia), gallium oxide, yttrium oxide (yttria), germanium oxide, and composite oxides thereof. It is done. Among these metal oxides, silicon oxide, aluminum oxide (corundum, etc.), zirconium oxide, and yttrium oxide are particularly preferable.

The metal oxide contained in the object to be polished may be a mixture of a plurality of metals or metalloid oxides, a mixture of a plurality of complex oxides, or a metal or metalloid. It may be a mixture of an oxide and a complex oxide. Further, the metal oxide contained in the object to be polished may be a composite material of a metal or metalloid oxide or composite oxide and other types of materials (for example, metal, carbon, ceramic).
Furthermore, the metal oxide contained in the object to be polished may be in the form of single crystal, polycrystal, sintered body (ceramic), or the like. When the metal oxide is in such a form, the entire polishing object can be made of a metal oxide. Alternatively, the metal oxide contained in the object to be polished may be in the form of an anodized film formed by anodizing a pure metal or alloy. That is, the metal oxide contained in the object to be polished may be an oxide formed on the surface of the metal and oxidized by the metal itself, such as an anodized film of pure metal or alloy.

When the metal oxide is in such a form, the polishing object can be made of a part of the metal oxide and the other part of another material. In the case where the metal oxide is an anodic oxide film, the object to be polished includes a part including the surface thereof made of a metal oxide, and the other part made of a pure metal or an alloy.
Examples of the anodized film include a film made of aluminum oxide, titanium oxide, magnesium oxide, or zirconium oxide.
In addition, a film is formed on the surface of a base material of a material different from the metal oxide (for example, metal, carbon, ceramic) by film processing such as thermal spraying (for example, plasma spraying, flame spraying), chemical vapor deposition (CVD), etc. By doing so, the polishing object may be configured.
Examples of the coating formed by thermal spraying include a metal oxide coating made of aluminum oxide, zirconium oxide, or yttrium oxide.
Examples of the film formed by chemical vapor deposition include a ceramic film made of silicon oxide, aluminum oxide, or silicon nitride.

(Abrasive grains)
The abrasive grains in the polishing composition of one embodiment of the present invention include abrasive grains having an average particle diameter in the range of 10 to 45 nm and abrasive grains having an average particle diameter in the range of 80 to 170 nm. In the present specification, for the sake of convenience, abrasive grains having an average particle diameter of 10 to 45 nm are referred to as small-diameter abrasive grains, and abrasive grains having an average particle diameter of 80 to 170 nm are referred to as large-diameter abrasive grains. The particle diameter, particle size distribution, major axis and minor axis of the abrasive grains are measured from the scanning electron microscope image of the abrasive grains using image analysis software or the like. The particle diameter of the abrasive grains can be obtained as a diameter of a circle having the same area as the area of the particles in the scanning electron microscope image. The average particle diameter of the abrasive grains is an average value of the particle diameters of a plurality of particles in the visual field range of the scanning electron microscope. The particle size distribution of the abrasive grains was converted from the particle diameters of a plurality of particles within the field of view of the scanning microscope to a volume, and the ratio was calculated. The values of the major axis and the minor axis of each particle can be obtained as the length of the long side and the short side of the minimum circumscribed rectangle in the scanning electron microscope image of the particle, respectively. The aspect ratio of the abrasive grains is a value obtained by dividing the value of the major axis of each particle by the value of the minor axis, and is an average value of the aspect ratios of a plurality of particles within the field of view of the scanning electron microscope.

It is preferable that the ratio of the total amount of the small particle size abrasive grains and the large particle size abrasive grains in the entire abrasive grains contained in the polishing composition is 90% by mass or more, and more preferably 95% by mass or more.
The proportion of the small-diameter abrasive grains in the whole abrasive grains contained in the polishing composition is preferably 75% by mass or more, and more preferably 78% by mass or more. Moreover, it is preferable that the ratio of the small particle size abrasive grain occupied to the whole abrasive grain contained in polishing composition is 83 mass% or less. When the proportion of the small-diameter abrasive grains is within the above range, it is possible to obtain a higher polishing rate without increasing the total amount of abrasive grains by increasing the point of action of the abrasive grains contacting the surface of the object to be polished. I can do it.

It is preferable that the ratio of the large-diameter abrasive grains in the entire abrasive grains contained in the polishing composition is 17% by mass or more. Moreover, it is preferable that the ratio of the large particle size abrasive grain to the whole abrasive grain contained in polishing composition is 29 mass% or less, More preferably, it is preferable that it is 23% mass or less. When the ratio of the large-diameter abrasive grains is within the above range, a higher polishing rate can be obtained without increasing the polishing load by increasing the local pressure applied to the surface of the object to be polished.

The ratio B / A of the particle diameter B of the largest number of abrasive grains to the grain diameter A of the largest number of abrasive grains in the small grain size abrasive grains is 2.5 or more. More preferably, it is preferably 3.0 or more, more preferably 3.5 or more. When the ratio of B to A is within the above range, a higher polishing rate can be obtained without increasing the polishing load by increasing the local pressure applied to the surface of the object to be polished.

In order to obtain the largest number of particles in the abrasive grains in each average particle size range, for example, the particle size having the largest number of distributions is determined by the particle size distribution of the particles measured by a particle size distribution measuring apparatus using a dynamic light scattering method. This can be done by specifying.
Although the upper limit of content of the abrasive grain in polishing composition is not specifically limited, It is preferable that it is 50 mass% or less, More preferably, it is 45 mass% or less. The smaller the abrasive content, the better the dispersion stability of the polishing composition, and the easier the handling of the polishing composition. According to the present invention, a high polishing rate can be realized with a small abrasive content. Therefore, the polishing process can be performed at a low cost.

The type of abrasive grain is not particularly limited as long as it is an abrasive grain generally used in a polishing composition, as long as the grain size and content of the abrasive grain satisfy the conditions specified in the present invention. . For example, silica, alumina, zirconia, zircon sand, ceria, titania, silicon carbide, titanium boride, diamond and the like may be used.
Among these, for example, colloidal silica, fumed silica, sol-gel silica, fumed alumina, colloidal alumina, alumina sol, fumed zirconia, alumina sol, fumed zirconia, colloidal zirconia, and zirconia sol are preferable. These abrasive grains may be used alone or in combination of two or more. Among these, fumed silica and colloidal silica may be used from the viewpoint that the surface of the object to be polished can be more efficiently smoothed.

(PH and pH adjuster)
It is preferable that pH of polishing composition is 5.0 or more, More preferably, it is 6.0 or more, More preferably, it is 6.5 or more. Moreover, it is preferable that pH of polishing composition is 10.0 or less, More preferably, it is preferable that it is 9.5 or less, More preferably, it is 9.0 or less. When the pH is within the above range, the polishing rate is improved. In addition, the polishing composition can be handled safely. When the pH is within the above range, the polishing rate tends to increase. The reason why the polishing rate becomes high at the above pH is presumed to be related to the zeta potential of the ceramic to be polished.

The pH of the polishing composition of the present invention may be adjusted with a pH adjuster. The pH adjuster adjusts the pH of the polishing composition, thereby controlling the polishing rate of the ceramic, the dispersibility of the abrasive grains, and the like. The pH adjuster can be used alone or in combination of two or more.
As the pH adjuster, known acids, bases, or salts thereof can be used. Specific examples of acids that can be used as pH adjusters include, for example, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid, formic acid, and acetic acid. , Propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n- Octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid Acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxy Eniru acetate, and phenoxy organic acids such as acetic acid. When an inorganic acid is used as a pH adjuster, sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and the like are particularly preferable from the viewpoint of improving the polishing rate. When an organic acid is used as a pH adjuster, glycolic acid, succinic acid, maleic acid Citric acid, tartaric acid, malic acid, gluconic acid, itaconic acid and the like are preferable.

Bases that can be used as pH adjusters include amines such as aliphatic amines and aromatic amines, organic bases such as quaternary ammonium hydroxide, alkali metal hydroxides such as potassium hydroxide, and hydroxides of alkaline earth metals. And ammonia and the like.
Among these, potassium hydroxide or ammonia is preferable from the viewpoint of availability.
Further, a salt such as an ammonium salt or an alkali metal salt of the acid may be used as a pH adjuster in place of the acid or in combination with the acid. In particular, in the case of a combination of a weak acid and a strong base, a strong acid and a weak base, or a combination of a weak acid and a weak base, a buffering action of pH can be expected. In a small amount, not only pH but also conductivity can be adjusted.

The addition amount of the pH adjusting agent is not particularly limited, and may be appropriately adjusted so that the polishing composition has a desired pH.
Another aspect of the present invention is a polishing method for polishing a metal or metalloid oxide using a polishing composition. In addition, another embodiment is a method for manufacturing a component that includes a metal or metalloid oxide or one or more of these composite materials using the polishing method of the above embodiment.

Using the polishing composition according to the embodiment of the present invention, an object to be polished made of a metal or semi-metal oxide crystal or the like can be polished at a high polishing rate. Although not intended to be bound by theory, the mechanism of this polishing function can be considered as follows. That is, when silica having a particle size of 80 to 170 nm or less and silica having a particle size of 10 to 45 nm have an appropriate particle size distribution and are contained in an appropriate content in the polishing composition, Is believed to synergistically enhance its mechanical polishing action, resulting in a significantly superior polishing rate. In this case, the main silica in the entire silica contained in the polishing composition is preferably a large particle size silica having a particle size of 80 to 170 nm, which has a large mechanical polishing action. On the other hand, it is considered that the solid-phase reaction between the abrasive grain surface and the object to be polished made of oxide crystals also contributes to the improvement of the polishing rate. Therefore, it is considered that by including silica having a sufficient surface area in the polishing composition, the sustainability of the polishing performance is improved and the polishing performance can be maintained. The present invention provides a remarkably excellent polishing rate by containing a proper amount of large particle size silica having a particle size of 80 to 170 nm and small particle size silica having a particle size of 10 to 45 nm in the polishing composition. Is.

(water)
The polishing composition of the present invention contains water as a dispersant or a solvent for dispersing or dissolving each component. From the viewpoint of suppressing the inhibition of the action of other components, water containing as little impurities as possible is preferable. Specifically, after removing impurity ions with an ion exchange resin, pure water from which foreign matters are removed through a filter is used. Water, ultrapure water, or distilled water is preferred.

(Other ingredients)
In order to improve the performance of the polishing composition of the present embodiment, if necessary, an additive having an action of further increasing the polishing rate, such as a complexing agent, an etching agent, and an oxidizing agent. You may contain. Moreover, you may contain the water-soluble polymer (The copolymer, its salt, and derivative | guide_body may be sufficient) which acts on the surface of a grinding | polishing target object or the surface of an abrasive grain. Furthermore, the polishing composition may further contain an additive such as a dispersant for improving the dispersibility of the abrasive grains and a dispersion aid for facilitating the redispersion of the aggregate, if necessary.

In addition, the polishing composition may further contain a known additive such as an antiseptic, an antifungal agent, and an antirust agent as necessary.
These additives are known in many patent literatures and the like as those that can be usually added in polishing compositions, and the types and addition amounts thereof are not particularly limited. However, the addition amount in the case of adding these additives is preferably less than 1% by mass, more preferably less than 0.5% by mass, and 0.1% by mass with respect to the polishing composition. More preferably, it is less than. These additives may be used individually by 1 type, and may use 2 or more types together.

Examples of complexing agents include inorganic acids, organic acids, amino acids, nitrile compounds, and chelating agents. Specific examples of the inorganic acid include sulfuric acid, nitric acid, boric acid, carbonic acid and the like. Specific examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n- Heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, malein Examples include acid, phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid. Organic sulfuric acids such as methanesulfonic acid, ethanesulfonic acid and isethionic acid can also be used. A salt such as an alkali metal salt of an inorganic acid or an organic acid may be used instead of the inorganic acid or the organic acid or in combination with the inorganic acid or the organic acid. Of these, glycine, alanine, malic acid, tartaric acid, citric acid, glycolic acid, isethionic acid or salts thereof are preferred.

Examples of chelating agents include carboxylic acid chelating agents such as gluconic acid, amine chelating agents such as ethylenediamine, diethylenetriamine, and trimethyltetraamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetramine hexaacetic acid. , Polyaminopolycarboxylic chelating agents such as diethylenetriaminepentaacetic acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetrakis (methylenephosphonic acid), diethylenetriaminepenta ( Methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4- Organic phosphonic acid chelating agents such as polycarboxylic acid, phenol derivatives, 1,3-diketones and the like.

Examples of the etching agent include inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid and hydrofluoric acid, organic acids such as acetic acid, citric acid, tartaric acid and methanesulfonic acid, inorganic alkalis such as potassium hydroxide and sodium hydroxide, Organic alkalis such as ammonia, amine, quaternary ammonium hydroxide and the like can be mentioned.
Examples of the oxidizing agent include hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchlorate, persulfate, nitric acid, potassium permanganate and the like.

Examples of water-soluble polymers, copolymers, salts and derivatives thereof include polycarboxylic acids such as polyacrylates, polysulfonic acids such as polyphosphonic acid and polystyrene sulfonic acid, polysaccharides such as chitansan gum and sodium alginate, hydroxyethyl cellulose And cellulose derivatives such as carboxymethyl cellulose, polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, sorbitan monooleate, and oxyalkylene polymers having a single kind or plural kinds of oxyalkylene units.

Examples of the dispersion aid include condensed phosphates such as pyrophosphate and hexametaphosphate. Examples of preservatives include sodium hypochlorite and the like. Examples of antifungal agents include oxazolines such as oxazolidine-2,5-dione.
Examples of the anticorrosive include surfactants, alcohols, polymers, resins, amines, pyridines, tetraphenylphosphonium salts, benzotriazoles, triazoles, tetrazoles, benzoic acid and the like.

Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Nonionic surfactants include ether types, ether ester types, ester types, and nitrogen-containing types, and anionic surfactants include carboxylates, sulfonates, sulfate esters, and phosphate esters. Can be mentioned. Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium chloride salts, benzethonium chloride, pyridinium salts, and imidazolinium salts, and amphoteric surfactants include carboxy surfactants. Examples include betaine type, aminocarboxylate, imidazolinium betaine, lecithin, and alkylamine oxide.

(Method for producing polishing composition)
The method for producing the polishing composition of the present embodiment is not particularly limited, and silica containing a large particle size silica having a predetermined content, average particle size, particle size distribution and aspect ratio and small particle size silica (abrasive) Granules) and various additives as desired can be produced by stirring and mixing in a liquid solvent such as water. For example, it can manufacture by stirring and mixing the silica containing a large particle size silica and the small particle size silica, and various additives, such as a pH adjuster. Although the temperature at the time of mixing is not specifically limited, 10 degreeC or more and 40 degrees C or less are preferable, you may heat in order to improve a melt | dissolution rate, and mixing time is not specifically limited, either.

The polishing composition may be a one-part type or a multi-part type having two or more parts. In addition, when using a polishing apparatus having a plurality of abrasive supply paths, two or more compositions are prepared in advance, and these compositions are mixed in the polishing apparatus to form a polishing composition. May be.
The polishing composition may be prepared by diluting a stock solution of the polishing composition with water. When the polishing composition is a two-pack type, the order of mixing and dilution of both compositions is arbitrary. For example, one composition may be diluted with water and then mixed with the other composition, both compositions may be mixed and diluted with water at the same time, or both compositions may be mixed. May be diluted with water after mixing.

(Polishing apparatus and polishing method)
The polishing composition can be used in an apparatus and conditions usually used for polishing an object to be polished comprising oxide crystals. As a polishing apparatus, a single-side polishing apparatus or a double-side polishing apparatus is generally used. The single-side polishing apparatus holds the object to be polished using a holder called a carrier, and while supplying the polishing composition, presses the surface plate to which the polishing pad is attached against one surface of the object to be polished and rotates the surface plate. Thus, one surface of the object to be polished is polished. The double-side polishing apparatus holds the object to be polished using a carrier and supplies the polishing composition from above while pressing the surface plate to which the polishing pad is applied against both surfaces of the object to be polished. Both surfaces of the object to be polished are polished by rotating. At this time, the object to be polished is polished by a physical action due to friction between the polishing pad and the polishing composition and the object to be polished and a chemical action that the polishing composition brings to the object to be polished.

The polishing conditions include the polishing load. In general, the greater the polishing load, the higher the frictional force between the abrasive grains and the object to be polished. As a result, mechanical processing characteristics are improved and the polishing rate is increased. The polishing load applied to the workpiece is not particularly limited, but is preferably 50 to 1,000 g / cm ² , more preferably 100 to 800 g / cm ² , and still more preferably 150 to 600 g / cm ² . . When the polishing load is within the above range, a sufficiently high polishing rate can be exhibited, and damage to the object to be polished and occurrence of surface defects can be reduced.

Also, the polishing conditions include linear velocity. In general, the number of revolutions of the polishing pad, the number of revolutions of the carrier, the size of the object to be polished, the number of objects to be polished, etc. affect the linear velocity. When the linear velocity is high, the frequency with which the abrasive grains come into contact with the object to be polished is high, so that the frictional force acting between the object to be polished and the abrasive grains increases, and the mechanical polishing action on the object to be polished increases. Also, the heat generated by friction may enhance the chemical polishing action by the polishing composition. The linear velocity is not particularly limited, but is preferably 10 to 300 m / min, and more preferably 30 to 200 m / min. When the linear velocity is within the above range, a sufficiently high polishing rate can be achieved, and an appropriate frictional force can be applied to the object to be polished. On the other hand, since friction generated directly between the polishing pad and the object to be polished does not contribute to polishing, it is preferable that the friction is as small as possible.

The polishing pad is not limited by physical properties such as material, thickness, or hardness. For example, an arbitrary polishing pad such as a polyurethane type having various hardness and thickness, a nonwoven fabric type, a suede type, a type including abrasive grains, or a type including no abrasive grains can be used.
The polishing composition described above can be used once for polishing and then recovered and used for polishing again. As an example of a method of reusing a polishing composition, a method of once collecting a used polishing composition discharged from a polishing apparatus in a tank and circulating it from the tank to the polishing apparatus again is used. It is done. By circulating the polishing composition, it is possible to reduce the amount of the polishing composition discharged as a waste liquid and reduce the amount of the polishing composition used. This is useful in that the environmental load can be reduced and the manufacturing cost of the object to be polished can be suppressed.

When the polishing composition is recycled, components such as silica in the polishing composition are consumed and lost by polishing. For this reason, you may replenish the polishing composition in circulation use for the decrease of components, such as a silica. The components to be replenished may be added individually to the polishing composition, or may be added to the polishing composition as a mixture containing two or more components at an arbitrary concentration. In this case, the polishing composition is adjusted to a state suitable for reuse, and the polishing performance is suitably maintained.
The polishing conditions include the supply rate of the polishing composition. The supply rate of the polishing composition depends on the type of object to be polished, the type of polishing apparatus, and other polishing conditions, but the polishing composition is uniformly supplied to the entire object to be polished and the polishing pad. It is preferable that the speed is sufficient.

Next, examples and comparative examples of the present invention will be described.
The composition shown in Table 1 was mixed with silica having a particle size and content, water as a liquid medium, and a pH adjuster as an additive, and the abrasive grains were dispersed in water. The thing was manufactured. Nitric acid and potassium hydroxide were used as pH adjusting agents, and the pH was adjusted to those shown in Table 1.
Using the polishing compositions of the inventive example and the comparative example, a rectangular plate-shaped member made of white zirconia ceramic (size: 60 mm length, 80 mm width) was polished under the following polishing conditions. And the mass of the rectangular plate-shaped member before grinding | polishing and the mass of the rectangular plate-shaped member after grinding | polishing were measured, and the grinding | polishing rate was computed from the mass difference before and behind grinding | polishing. The results are shown in Table 1.

(Polishing conditions)
Polishing device: Single-side polishing device (surface plate diameter: 380 mm)
Abrasive cloth: Abrasive cloth made of polyurethane Abrasive load: 225 gf / cm ²
Surface plate rotation speed: 90 min ^-1
Polishing speed (linear speed): 71.5 m / min Polishing time: 15 minutes Supply speed of polishing composition: 26 mL / min

The content of silica contained in each polishing composition, and the ratio of silica having an average particle size of 10 to 45 nm, 46 to 70 nm, and 80 to 170 nm therein are as shown in Table 1. In the comparative example, the content of silica having an average particle size of 46 to 79 nm is also shown. In Examples 1 to 8 and Comparative Examples 2, 5, and 7, the largest number of silica particles having an average particle diameter of 10 to 45 nm is 33 nm, and the largest among silica particles having an average particle diameter of 80 to 170 nm. The particle size of the large number is 130 nm. However, in Comparative Example 3, the particle diameter of the largest number of silica particles having an average particle diameter of 10 to 45 nm is 27 nm, and the particle diameter of the largest particle number of silica having an average particle diameter of 80 to 170 nm is 130 nm. The average particle size of silica was measured using image analysis software. The measurement was performed on a total of 1000 or more silicas selected from images of a scanning electron microscope. Table 1 shows the contents when the average particle diameter is within the range of the large particle diameter or the small particle diameter. The value of B / A was calculated by specifying the most numerous particle diameter in the abrasive grains in each average particle diameter range by the particle size distribution of the particles measured by a particle size distribution measuring apparatus by a dynamic light scattering method. . Moreover, in order to calculate the polishing rate of each polishing composition, the weight of the substrate was measured before and after polishing. The polishing rate calculated from the difference in substrate weight before and after polishing is shown in the column “Polishing rate” in Table 1.

As shown in Table 1, when zirconia was polished using the polishing composition of the example, a higher polishing rate was obtained compared to the comparative example.
In Comparative Example 1, the small particle size silica is not included. In Comparative Example 2, the content of the small particle size silica is less than 40% by mass, and the content of the large particle size silica exceeds 29% by mass. The content of the small particle size silica exceeds 83% and the content of the large particle size silica is less than 17% by mass. Comparative Example 4 does not include the large particle size silica, and Comparative Example 5 includes the large particle size silica. In Comparative Example 6, the small particle size silica is not included, and the content of the large particle size silica exceeds 29 mass%. In Comparative Example 7, the content of the small particle size silica is less than 40%, which is large. The particle size of silica exceeds 29% by mass.

Claims (8)

1. A polishing composition containing water and abrasive grains, wherein the abrasive grains have an average particle diameter of 10 to 45 nm and 71 to 83 mass% of the total abrasive grains and an average particle diameter of 80 to 170 nm. The total amount of abrasive grains having an average particle diameter of 10 to 45 nm and abrasive grains having an average particle diameter of 80 to 170 nm is the total amount of abrasive grains. Polishing composition characterized by occupying 90 mass% or more in the inside.
2. Ratio of the particle diameter B of the abrasive grains having the largest number in the abrasive grains having the average particle diameter of 80 to 170 nm to the grain diameter A of the abrasive grains having the largest number in the abrasive grains having the average particle diameter of 10 to 45 nm. The polishing composition according to claim 1, wherein B / A is 2.5 or more.
3. The polishing composition according to claim 1 or 2, wherein the pH is 5.0 to 10.0.
4. The polishing composition according to any one of claims 1 to 3, wherein the abrasive grains are silica.
5. 5. The polishing material according to claim 1, wherein the polishing material is used for polishing a surface of an object to be polished containing at least one metal or metalloid oxide or a composite material thereof. Composition.
6. The polishing object includes one or more oxides of one or two or more metals or metalloids selected from Groups 3, 4, and 13, or a composite material thereof. 6. The polishing composition according to any one of 5 above.
7. A polishing method for polishing an object to be polished using the polishing composition according to any one of claims 1 to 6.
8. A method for producing a component containing at least one metal or semi-metal oxide or a composite material thereof using the polishing method according to claim 7.