JP2014024156A - Abradant, abrasive composition, polishing method of crustaceous material, and manufacturing method of crustaceous material substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abradant which easily polishes a crustaceous material at high polishing speed while suppressing generation of surface flaws, an abrasive composition, a polishing method of the crustaceous material using the abrasive composition, and a manufacturing method of a crustaceous material substrate.SOLUTION: An abradant contains zirconium oxide particles, and at least one kind of oxide particles selected from aluminium oxide particles and silicon oxide particles. An abrasive composition contains the abradant and water, and a content of the abradant is 0.1 mass% or more. A polishing method of a crustaceous material uses the abrasive composition to polish the crustaceous material. A manufacturing method of a crustaceous material substrate includes a polishing process of polishing a substrate raw material consisting of the crustaceous material by using the abrasive composition.

Description

  The present invention relates to an abrasive and a polishing composition containing zirconium oxide particles. The present invention also relates to a method for polishing a hard and brittle material using the polishing composition and a method for producing a hard and brittle material substrate.

  For example, for polishing compositions used for polishing substrates made of hard and brittle materials such as glass substrates for hard disks, glass substrates for liquid crystal display panels, synthetic quartz substrates for photomasks, the quality of the substrates after polishing is improved. From this point of view, there is a demand for few surface defects such as scratches. In addition, from the viewpoint of shortening the time required for the polishing operation, a high polishing rate (removal rate) of the substrate is also required.

  A polishing composition containing a cerium oxide-based abrasive is known as a polishing composition used for polishing a substrate made of a hard and brittle material (see Patent Document 1). However, in Japan today, rare earths such as cerium oxide depend on imports from abroad. For this reason, there is a concern that rare earth supplies may be insufficient due to the international situation, and price increases associated therewith. Therefore, development of an abrasive using an alternative material to replace rare earth is desired.

  On the other hand, Patent Document 2 discloses a polishing composition containing zirconium oxide fine particles and a polishing accelerator as a polishing composition used for polishing an aluminum substrate for a magnetic disk.

JP 2010-16064 A JP-A-10-121034

  An object of the present invention is to provide an abrasive and a polishing composition that can be easily polished at a high polishing rate while suppressing generation of surface defects. Another object of the present invention is to provide a method for polishing a hard and brittle material and a method for producing a hard and brittle material substrate using the polishing composition.

  In order to achieve the above object, in one embodiment of the present invention, an abrasive containing zirconium oxide particles, the abrasive containing at least one oxide particle selected from aluminum oxide particles and silicon oxide particles Is provided.

The oxide particles are preferably contained in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the zirconium oxide particles.
The average primary particle diameter of the zirconium oxide particles is preferably 0.3 μm or less.

The average secondary particle diameter of the zirconium oxide particles is preferably 0.1 μm or more and 5 μm or less.
In another aspect of the present invention, there is provided a polishing composition containing the abrasive and water, wherein the polishing composition has a content of 0.1% by mass or more.

In another aspect of the present invention, a polishing method for polishing a hard and brittle material using the polishing composition is provided.
In another aspect of the present invention, there is provided a method for producing a hard and brittle material substrate including a polishing step of polishing a substrate material made of a hard and brittle material using the polishing composition.

  ADVANTAGE OF THE INVENTION According to this invention, the abrasive | polishing material and polishing composition which are easy to grind | polish at a high grinding | polishing speed, suppressing generation | occurrence | production of a surface defect are provided. Further, a method for polishing a hard and brittle material using the polishing composition and a method for producing a hard and brittle material substrate are provided.

Hereinafter, an embodiment of the present invention will be described.
The polishing composition of this embodiment contains an abrasive and water. The abrasive contains zirconium oxide particles and specific oxide particles. The polishing composition can be suitably used for polishing hard and brittle materials such as sapphire, silicon nitride, silicon carbide, silicon oxide, glass, gallium nitride, gallium arsenide, indium arsenide, and indium phosphide.

  The zirconium oxide particles contained in the abrasive may be made of crystalline zirconia such as cubic, tetragonal or monoclinic, or may be made of amorphous zirconia. . As the abrasive, it is preferable to use zirconium oxide particles made of tetragonal or monoclinic zirconia. The crystal structure of the zirconium oxide particles can be measured with a powder X-ray diffractometer such as MiniFlex manufactured by Rigaku Corporation. For example, the crystallite size calculated based on the diffraction intensity around 28.0 ° and the diffraction intensity around 31.0 ° measured using a powder X-ray diffractometer is 330 mm or more Indicates that the crystal system of the zirconium oxide particles is monoclinic and that the crystallite size is large.

  The zirconium oxide particles may contain impurities. However, the purity of the zirconium oxide particles is preferably as high as possible. Specifically, the purity of the zirconium oxide particles is preferably 99% by mass or more, more preferably 99.5% by mass or more, and further preferably 99.8% by mass or more. When the purity of the zirconium oxide particles is 99% by mass or more, the polishing rate of the hard and brittle material by the polishing composition is improved by the increase in purity. In this respect, if the purity of the zirconium oxide particles is 99% by mass or more, preferably 99.5% by mass or more, more preferably 99.8% by mass or more, the polishing rate of the hard and brittle material by the polishing composition is practically used. It becomes easy to improve to a particularly suitable level. The purity of the zirconium oxide particles can be calculated from the measured value of the total amount of zirconium oxide and hafnium oxide by a fluorescent X-ray analyzer such as XRF-1800 manufactured by Shimadzu Corporation.

  Examples of the impurities contained in the zirconium oxide particles include calcium, magnesium, hafnium, yttrium, silicon, aluminum, iron, copper, chromium, titanium, and oxides thereof. However, the amount of impurities contained in the zirconium oxide particles is preferably small. For example, the content of silicon oxide in the zirconium oxide particles is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.2% by mass or less. The contents of aluminum oxide and iron oxide in the zirconium oxide particles are each preferably 0.1% by mass or less. In addition, content of impurities, such as a silicon oxide, aluminum oxide, and an iron oxide, can be computed from the measured value by an ICP emission-spectral-analysis apparatus, for example.

  Impurities contained in the zirconium oxide particles can also be measured by a powder X-ray diffraction method such as MiniFlex manufactured by Rigaku Corporation. For example, the content of quartz silica in the zirconium oxide particles can be measured based on the intensity of the diffraction peak at 2θ of around 26.5 ° measured using a powder X-ray diffractometer. The smaller the intensity of the diffraction peak, the smaller the content of quartz silica as an impurity. In addition, it is preferable that the intensity | strength of the said diffraction peak is 200 cps or less, and it is more preferable that the said diffraction peak does not appear, ie, it does not contain the quartz silica as an impurity substantially.

It is preferable that the specific surface area of a zirconium oxide particle is 15.0 m < ² > / g or less, More preferably, it is 13.0 m < ² > / g or less, More preferably, it is 9.0 m < ² > / g or less. The specific surface area of the zirconium oxide particles is preferably 1.0 m ² / g or more, more preferably 2.0 m ² / g or more. By making the specific surface area of the zirconium oxide particles in the range of 1.0 m ² / g or more and 15.0 m ² / g or less, the polishing rate of the hard and brittle material by the polishing composition is improved to a practically suitable level. It becomes easy. In addition, the specific surface area of a zirconium oxide particle can be measured with the specific surface area measuring apparatus by nitrogen adsorption methods, such as Shimazu Corporation FlowSorbII2300, for example.

  The average primary particle diameter of the zirconium oxide particles is preferably 0.3 μm or less, more preferably 0.2 μm or less, and still more preferably 0.15 μm or less. By reducing the average primary particle size, the surface roughness of the hard and brittle material after polishing is reduced. In this respect, if the average primary particle diameter of the zirconium oxide particles is 0.3 μm or less, preferably 0.2 μm or less, more preferably 0.15 μm or less, the surface roughness of the hard and brittle material after polishing is practically used. It becomes easy to reduce to a suitable level.

  The primary particle diameter of the zirconium oxide particles can be calculated based on a photograph taken with a scanning electron microscope such as S-4700 manufactured by Hitachi High-Technologies Corporation. For example, a predetermined number (for example, 100 or more) of particles are randomly selected from an electron micrograph of zirconium oxide particles photographed at a magnification of 10,000 to 50,000 times. About the selected particle | grains, an area is measured from the image of an electron micrograph, and the diameter of the circle | round | yen which becomes the same area as the area is calculated | required as a primary particle diameter of a zirconium oxide particle. And the average value of the primary particle diameter (50% particle diameter in the volume-based integrated fraction) is calculated as the average primary particle diameter. In addition, calculation of a primary particle diameter and an average primary particle diameter can be performed using a commercially available image analyzer.

  The average secondary particle diameter of the zirconium oxide particles is preferably 0.1 μm or more, more preferably 0.3 μm or more, and further preferably 0.5 μm or more. By increasing the average secondary particle size, the polishing rate of the hard and brittle material by the polishing composition is improved. In this respect, if the average secondary particle diameter of the zirconium oxide particles is 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, the polishing rate of the hard and brittle material by the polishing composition is practically used. It becomes easy to improve to a particularly suitable level.

  The average secondary particle diameter of the zirconium oxide particles is preferably 5 μm or less, more preferably 3 μm or less, and still more preferably 1.5 μm or less. By reducing the average secondary particle size, the dispersion stability of the polishing composition is improved, and surface defects such as scratches generated in the hard and brittle material after polishing are suppressed. In this respect, if the average secondary particle diameter of the zirconium oxide particles is 5 μm or less, preferably 3 μm or less, more preferably 1.5 μm or less, the dispersion stability of the polishing composition and the surface of the hard and brittle material after polishing It becomes easy to improve the accuracy to a particularly suitable level for practical use.

  The average secondary particle diameter of the zirconium oxide particles is a 50% particle diameter in a volume-based integrated fraction, and is measured by, for example, a laser diffraction / scattering particle size distribution measuring apparatus such as LA-950 manufactured by Horiba, Ltd. Can be sought.

  The method for producing zirconium oxide particles is not particularly limited. For example, zirconium oxide particles produced by either a wet method or a dry method can be used. In the wet method, zirconium-containing ores such as zircon and zircon sand are used as raw materials, and the zirconium compound obtained by melting, dissolving and refining it is hydrolyzed to obtain zirconium hydroxide, and then calcined and pulverized. Zirconium oxide particles are obtained. In the dry method, zirconium oxide particles are obtained by removing silicon oxide from zirconium-containing ores such as zircon and zircon sand by high-temperature treatment, or by pulverizing zirconium oxide ores such as badelite and then removing impurities.

  The dry method can reduce the manufacturing cost than the wet method. However, in addition to being able to obtain zirconium oxide particles with higher purity in the wet method than in the dry method, the particle size and specific surface area of the resulting zirconium oxide particles can be adjusted by operations such as firing, pulverization, and classification. Is relatively easy. Therefore, it is preferable that the zirconium oxide particles in the present embodiment are produced by a wet method. In order to obtain high-purity zirconium oxide particles by a dry method, it is preferable to include a step of sublimating impurities such as silicon oxide by high-temperature treatment. In this case, the high-temperature treatment is performed by heating the raw ore to, for example, an arc furnace, usually at 2000 ° C. or higher, preferably about 2700 ° C. or higher.

  In the method for producing zirconium oxide particles, the pulverization step of pulverizing the zirconium oxide particles is a step necessary for making the particle diameters of the obtained zirconium oxide particles small and removing impurities. By this pulverization, at least a part of the secondary particles formed by agglomeration of the primary particles collapses into particles having the primary particles as a minimum unit. Examples of the method of pulverizing the zirconium oxide particles include a method using a ball mill, a bead mill, a hammer mill or the like using media, and a method using a jet mill or the like that does not use media. Further, a wet method using a solvent and a dry method using no solvent can be given.

  It is preferable to employ a grinding method that does not use media as compared with a grinding method that uses media. In the case of a pulverization method using media such as balls and beads, there is a possibility that debris generated by media wear or destruction may be mixed in the zirconium oxide particles. Further, the shape of the primary particles is changed by the pressure received from the media, which may affect the specific surface area and polishing performance of the zirconium oxide particles. On the other hand, in the case of a pulverizing method that does not use media, the above-mentioned concern is greatly reduced.

  It is preferable to employ a dry pulverization method as compared with a wet pulverization method. In the case of a pulverization method by a wet method, it is necessary to add a dispersant. If this dispersing agent is mixed in the zirconium oxide particles, the stability of the abrasive may be affected. In order to obtain zirconium oxide particles in a dry powder state, it is necessary to perform a drying step after the pulverization step. On the other hand, in the case of a pulverization method by a dry method, a dispersant is not required and a drying step is not required. In the case of a pulverization method using a dry method, the pulverization efficiency is relatively high, and zirconium oxide particles having a desired particle diameter can be obtained efficiently. Therefore, it is particularly preferable that the pulverization step employs a method using a jet mill or the like that does not use media, and a pulverization method using a dry method.

  The content of zirconium oxide particles in the abrasive is preferably 50% by mass or more, and more preferably 90% by mass or more. By increasing the content of the zirconium oxide particles, the polishing rate of the hard and brittle material by the polishing composition is improved.

  The abrasive contains at least one oxide particle selected from aluminum oxide particles and silicon oxide particles (hereinafter referred to as the above oxide particles) as specific oxide particles. By using the oxide particles together with the zirconium oxide particles, surface defects such as scratches generated on the surface after polishing are suppressed without reducing the polishing rate of the hard and brittle material by the polishing composition. Examples of the oxide particles include fumed alumina, fumed silica, and colloidal silica. Among the oxide particles, fumed alumina or fumed silica is preferably used, and fumed silica is more preferably used. When preferable fine oxide particles are used, the effect of suppressing surface defects such as scratches generated on the surface after polishing can be more remarkably obtained, and the surface accuracy can be easily improved to a particularly suitable level. .

  The average primary particle diameter of the oxide particles is preferably 1 nm or more, more preferably 5 nm or more, still more preferably 10 nm or more, and particularly preferably 13 nm or more. By increasing the average primary particle size, the polishing rate of the hard and brittle material by the polishing composition is improved. In this respect, when the average primary particle diameter of the oxide particles is 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and further preferably 13 nm or more, the polishing rate of the hard and brittle material by the polishing composition is practically used. It becomes easy to improve to a particularly suitable level.

  The average primary particle diameter of the oxide particles is preferably 80 nm or less, more preferably 40 nm or less, still more preferably 30 nm or less, and particularly preferably 27 nm or less. By reducing the average primary particle size, the surface roughness of the hard and brittle material after polishing is reduced. In this respect, if the average primary particle size of the oxide particles is 80 nm or less, preferably 40 nm or less, more preferably 30 nm or less, and even more preferably 27 nm or less, the surface roughness of the hard and brittle material after polishing is practically used. It becomes easy to improve to a particularly suitable level.

  In addition, the average primary particle diameter of the oxide particles can be calculated from the specific surface area and mass of the particles, for example. The specific surface area of the particles can be measured by a specific surface area measuring device using a nitrogen adsorption method such as FlowSorbII2300 manufactured by Shimadzu Corporation.

  The average secondary particle diameter of the oxide particles is preferably 5 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more. By increasing the average secondary particle size, the polishing rate of the hard and brittle material by the polishing composition is improved. In this respect, if the average secondary particle diameter of the zirconium oxide particles is 5 nm or more, preferably 10 nm or more, more preferably 15 nm or more, the polishing rate of the hard and brittle material by the polishing composition is practically particularly suitable. It becomes easy to improve to.

  The average secondary particle diameter of the oxide particles is preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less, and particularly preferably 60 nm or less. By reducing the average secondary particle size, the surface roughness of the hard and brittle material after polishing is reduced. In this respect, if the average secondary particle diameter of the oxide particles is 200 nm or less, preferably 150 nm or less, more preferably 100 nm or less, and even more preferably 60 nm or less, the surface roughness of the hard and brittle material after polishing is practically used. It becomes easy to improve to a particularly suitable level. The average secondary particle diameter of the oxide particles can be measured by a dynamic light scattering method using, for example, Nanotrac UPA-UT151 manufactured by Nikkiso Co., Ltd.

  The content of the oxide particles in the abrasive is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the zirconium oxide particles. By increasing the content of the oxide particles, surface defects such as scratches are suppressed. The content of the oxide particles in the abrasive is preferably 20 parts by mass or less, more preferably 15 parts by mass or less with respect to 100 parts by mass of the zirconium oxide particles. By reducing the content of the oxide particles, the polishing rate is improved.

  The abrasive may further contain other particles in addition to the zirconium oxide particles and the oxide particles. Examples of the other particles include other oxide particles such as cerium oxide particles and titanium oxide particles, and zircon particles. For example, the abrasive of the present embodiment may contain zirconium oxide particles and aluminum oxide particles, and cerium oxide particles. When cerium oxide is contained as the other particles, the content of cerium oxide in the abrasive is preferably less than 40% by mass, more preferably less than 9% by mass.

  The average secondary particle diameter of the entire particles in the abrasive is preferably 0.1 μm or more, more preferably 0.3 μm or more, and further preferably 0.5 μm or more. By increasing the average secondary particle size, the polishing rate of the hard and brittle material by the polishing composition is improved. In this respect, if the average secondary particle diameter of the abrasive is 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, the polishing rate of the hard and brittle material by the polishing composition is practically used. It becomes easy to improve to a particularly suitable level.

  The average secondary particle diameter of the entire particles in the abrasive is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1.5 μm or less. By reducing the average secondary particle size, the dispersion stability of the polishing composition is improved, and surface defects such as scratches generated in the hard and brittle material after polishing are suppressed. In this respect, if the average secondary particle diameter of the abrasive is 5 μm or less, preferably 3 μm or less, more preferably 1.5 μm or less, the dispersion stability of the polishing composition and the surface of the hard and brittle material after polishing It becomes easy to improve the accuracy to a particularly suitable level for practical use. The average secondary particle diameter of the abrasive is a 50% particle diameter in a volume-based cumulative fraction, and is determined by, for example, a laser diffraction / scattering particle size distribution measuring apparatus such as LA-950 manufactured by Horiba, Ltd. be able to.

  The number of coarse particles having a secondary particle diameter of 5 μm or more in the abrasive is preferably as small as possible. Specifically, the number of the coarse particles per mL of the aqueous dispersion containing 1% by mass of the abrasive is preferably 10,000,000 or less, more preferably 5,000,000 or less. More preferably, it is 2,000,000 or less. By reducing the number of coarse particles, surface defects such as scratches generated in the hard and brittle material after polishing are suppressed. In this respect, if the number of coarse particles is 10,000,000 or less, preferably 5,000,000 or less, more preferably 2,000,000 or less, the surface of the hard and brittle material after polishing It becomes easy to improve the accuracy to a particularly suitable level for practical use. The number of coarse particles can be determined by a number counting type particle size distribution analyzer such as AccuSizer 780FX manufactured by Paeticle Sizing Systems.

  Polishing composition contains the said abrasive | polishing material and water. The content of the abrasive in the polishing composition is preferably 0.1% by mass or more, more preferably 1% by mass or more, and further preferably 3% by mass or more. By increasing the content of the abrasive, the polishing rate of the hard and brittle material by the polishing composition is improved. In this respect, when the content of the abrasive in the polishing composition is 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, polishing of the brittle material by the polishing composition It becomes easy to increase the speed to a particularly suitable level for practical use.

  It is preferable that pH of polishing composition is 3 or more. Moreover, it is preferable that pH of polishing composition is 12 or less. If the pH of the polishing composition is within the above range, it becomes easy to improve the polishing rate of the hard and brittle material by the polishing composition to a practically particularly suitable level.

  The pH of the polishing composition can be adjusted using various acids, bases, or salts thereof. Specifically, organic acids such as carboxylic acid, organic phosphonic acid and organic sulfonic acid, inorganic acids such as phosphoric acid, phosphorous acid, sulfuric acid, nitric acid, hydrochloric acid, boric acid and carbonic acid, tetramethylammonium hydroxide, trimethanolamine Organic bases such as monoethanolamine, inorganic bases such as potassium hydroxide, sodium hydroxide and ammonia, or salts thereof are preferably used.

  A cerium salt or a zirconium salt may be added to the polishing composition to promote polishing. Examples of the cerium salt include cerium ammonium nitrate, cerium nitrate, cerium chloride, cerium sulfate, and the like. Examples of the zirconium salt include zirconium oxychloride, zirconium nitrate, zirconium carbonate, zirconium hydroxide and the like.

  The content of the cerium salt in the polishing composition is preferably 2 mM or more, more preferably 20 mM or more. Moreover, it is preferable that content of the zirconium salt in polishing composition is 1 mM or more, More preferably, it is 10 mM or more. By increasing the content of cerium salt or zirconium salt, the polishing rate of the hard and brittle material is improved.

  The content of the cerium salt in the polishing composition is preferably 360 mM or less. Moreover, it is preferable that content of the zirconium salt in polishing composition is 180 mM or less. In addition, when cerium salt is added to the polishing composition, precipitation of cerium salt may occur depending on the type of alkali used for pH adjustment. If the cerium salt is precipitated, the effect of promoting polishing by adding the cerium salt may not be sufficiently obtained.

  A dispersing agent may be added to the polishing composition to improve dispersion stability. Examples of the dispersant include polyphosphates such as sodium hexametaphosphate and sodium pyrophosphate. Also, certain water-soluble polymers or salts thereof can be used as a dispersant. By adding the dispersant, the dispersion stability of the polishing composition is improved, and the supply of the polishing composition can be stabilized by making the slurry concentration uniform.

  Examples of the water-soluble polymer used as the dispersant include polycarboxylic acids, polycarboxylic acid salts, polysulfonic acid, polysulfonic acid salts, polyamines, polyamides, polyols, polysaccharides, and derivatives and copolymers thereof. Is mentioned. Specifically, polystyrene sulfonate, polyisoprene sulfonate, polyacrylate, polymaleic acid, polyitaconic acid, polyvinyl acetate, polyvinyl alcohol, polyglycerin, polyvinylpyrrolidone, a copolymer of isoprene sulfonic acid and acrylic acid , Polyvinylpyrrolidone polyacrylic acid copolymer, polyvinylpyrrolidone vinyl acetate copolymer, naphthalenesulfonic acid formalin condensate salt, diallylamine hydrochloride sulfur dioxide copolymer, carboxymethylcellulose, carboxymethylcellulose salt, hydroxyethylcellulose, hydroxypropylcellulose , Pullulan, chitosan, chitosan salts and the like.

  The content of the dispersant in the polishing composition is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and further preferably 0.02% by mass or more. If the content of the dispersant is 0.001% by mass or more, it is easy to obtain a polishing composition having good dispersion stability.

  On the other hand, when an excessive amount of the dispersant is added, there is a tendency that the precipitate generated by the precipitation of the abrasive in the polishing composition during storage or transportation becomes strong. Therefore, when using the polishing composition, it is difficult to disperse the precipitate, that is, the redispersibility of the abrasive in the polishing composition may be reduced. Therefore, the content of the dispersant in the polishing composition is preferably 1% by mass or less, more preferably 0.2% by mass or less. When the content of the dispersant is 1% by mass or less, the storage stability of the polishing composition can be improved without reducing the redispersibility of the abrasive in the polishing composition.

Next, a method for preparing the polishing composition of the embodiment will be described.
The polishing composition is prepared by dispersing an abrasive containing zirconium oxide particles and the above oxide particles in water, and adding a known additive as necessary. The mixing order of each component at the time of preparing polishing composition is arbitrary. For example, the polishing composition may be prepared by producing a concentrated composition containing an abrasive, water and additives, and diluting the concentrated composition with water. Further, the polishing composition may be prepared by dispersing an abrasive in an aqueous solution in which the additive is dissolved. Moreover, you may prepare polishing composition by mixing a powdery additive with a powdery abrasive and adding water to the mixture.

Next, the manufacturing method of the hard-brittle material board | substrate using the polishing composition of embodiment is demonstrated.
The manufacturing method of a hard and brittle material substrate includes a polishing step of polishing a substrate material made of a hard and brittle material using the polishing composition of the embodiment.

  Polishing of the substrate material using the polishing composition in the polishing step can be performed using the same apparatus and conditions as those normally used for polishing the substrate material. As the polishing apparatus, for example, a single-side polishing apparatus or a double-side polishing apparatus can be used. When using a single-side polishing machine, hold the substrate raw material using a carrier called a carrier, and press the surface plate with the polishing pad on one side of the substrate raw material, and then polish the substrate raw material against the substrate raw material. One side of the substrate raw material is polished by rotating the surface plate while supplying the material. When a double-side polishing apparatus is used, the substrate raw material is held using a holder called a carrier, and the upper and lower surface plates to which the polishing pads are respectively attached are pressed against both surfaces of the substrate raw material. Then, while supplying the polishing composition to the substrate material from above, the two surface plates are rotated in opposite directions to polish both surfaces of the substrate material. In the polishing step, the substrate raw material is polished by a physical action due to friction between the polishing pad and the polishing composition and the substrate raw material, and a chemical action that the polishing composition brings to the substrate raw material.

As the load during the polishing process, that is, the polishing load is increased, the polishing rate increases. The polishing load when polishing the substrate raw material using the polishing composition is not particularly limited, but is preferably 50 g or more and 1,000 g or less, more preferably 70 g or more and 800 g or less per 1 cm ^{2 of the} substrate surface area. . When the polishing load is within the above range, a practically sufficient polishing rate is obtained, and surface defects such as scratches generated on the substrate surface after polishing are suppressed.

  The linear velocity during the polishing process, that is, the polishing linear velocity, is generally affected by parameters such as the number of revolutions of the polishing pad, the number of carrier revolutions, the size of the substrate material, and the number of substrate materials. As the linear velocity increases, the frictional force applied to the substrate material increases, so that the substrate material is more strongly subjected to a mechanical polishing action. Further, since the frictional heat increases, the chemical polishing action by the polishing composition may be strengthened. However, if the linear velocity is too high, the polishing pad may not sufficiently rub against the substrate material, and the polishing rate may decrease. The linear velocity when the substrate material is polished using the polishing composition is not particularly limited, but is preferably 10 m / min or more and 150 m / min or less, more preferably 30 m / min or more and 100 m / min or less. When the linear velocity is within the above range, it is easy to obtain a practically sufficient polishing rate.

  The supply rate of the polishing composition to the polishing apparatus during the polishing step is appropriately set depending on the type of substrate raw material to be polished, the type of polishing apparatus, polishing conditions, and the like. However, it is preferable that the supply speed be sufficient to supply the polishing composition uniformly to the entire substrate material and polishing pad.

  The polishing pad used for polishing the substrate material using the polishing composition is not particularly limited in terms of its material, physical properties such as hardness and thickness. For example, any type such as a polyurethane type, a nonwoven fabric type, and a suede type may be used. The polishing pad may contain abrasive grains or may not contain abrasive grains. Further, the hardness and thickness of the polishing pad are not particularly limited.

  If the substrate material is a substrate that requires particularly high surface accuracy, such as a semiconductor substrate, a hard disk substrate, a liquid crystal display panel, or a synthetic quartz substrate for a photomask, a further fine polishing step may be performed after the polishing step. preferable. In the fine polishing step, the surface of the substrate material after the polishing step is further polished using a polishing composition containing a fine polishing abrasive, that is, a fine polishing composition. The pH of the fine polishing composition is preferably 1 or more and 4 or less, or 9 or more and 11 or less. The pH of the fine polishing composition can be adjusted using various acids, bases or salts thereof as in the polishing composition.

  The polishing material for fine polishing preferably has an average particle size of 0.15 μm or less, more preferably 0.10 μm or less, and still more preferably 0, from the viewpoint of reducing waviness, roughness, and defects on the substrate surface. 0.07 μm or less. From the viewpoint of improving the polishing rate, the average particle size of the fine polishing abrasive is preferably 0.01 μm or more, more preferably 0.02 μm or more. The average particle diameter of the abrasive for fine polishing can be measured by a dynamic light scattering method using, for example, Nanotrac UPA-UT151 manufactured by Nikkiso Co., Ltd.

By passing through the polishing step and, if necessary, the fine polishing step, the substrate raw material made of a hard and brittle material becomes a hard and brittle material substrate with improved surface accuracy.
According to the embodiment described in detail above, the following effects are exhibited.

  (1) The polishing composition contains an abrasive containing zirconium oxide particles and oxide particles and water. The oxide particles are at least one oxide particle selected from aluminum oxide particles and silicon oxide particles.

  The zirconium oxide particles contained in the polishing composition are particularly excellent in the ability to polish hard and brittle materials. Therefore, it can be suitably used for polishing hard and brittle materials such as glass, ceramics, stone, and semiconductor materials. In particular, among hard and brittle materials, sapphire, silicon nitride, silicon carbide, silicon oxide, glass, gallium nitride, gallium arsenide, indium arsenide, and indium phosphide can be used particularly suitably. Furthermore, a hard and brittle material made of glass or oxide such as quartz glass, soda lime glass, aluminosilicate glass, borosilicate glass, aluminoborosilicate glass, alkali-free glass, crystallized glass, soda aluminosilicate glass, silicon oxide film, etc. Can be suitably used as an alternative to conventional abrasives and polishing compositions mainly composed of cerium oxide. Furthermore, by using the zirconium oxide particles and the specific oxide particles in common, it is possible to polish the hard and brittle material at a high polishing rate while suppressing the generation of surface defects.

  (2) Preferably, the oxide particles are contained in a range of 1 to 20 parts by mass with respect to 100 parts by mass of the zirconium oxide particles. Thereby, surface defects, such as a scratch, are suppressed.

(3) Preferably, the average primary particle diameter of the zirconium oxide particles is 0.3 μm or less, whereby the surface roughness of the hard and brittle material after polishing can be reduced.
(4) Preferably, the average secondary particle diameter of the zirconium oxide particles is 0.1 μm or more and 5 μm or less. Thereby, the effect of polishing the hard and brittle material at a high polishing rate can be obtained more significantly while suppressing the generation of surface defects.

  (5) The method for polishing a hard and brittle material includes a step of polishing the hard and brittle material using the polishing composition described in the above section (1). This makes it possible to efficiently obtain a hard and brittle material with improved surface accuracy.

  (6) The manufacturing method of a hard and brittle material substrate includes a polishing step of polishing a substrate raw material made of a hard and brittle material using the polishing composition described in the above section (1). Thereby, the hard-brittle material board | substrate with which the surface precision of the surface was raised can be obtained efficiently.

The embodiment may be modified as follows.
-You may add an additive in the said polishing composition as needed. Moreover, you may add an additive in the said fine polishing composition as needed. Examples of additives include chelating agents, surfactants, antiseptics, antifungal agents, and rust inhibitors.

  The polishing composition and the fine polishing composition may be manufactured and sold in the form of a dilution stock solution, and may be used after being diluted. That is, it may be prepared by diluting the dilution stock solution with water.

  The polishing composition and the fine polishing composition may be manufactured and sold in the form of a dispersion / dissolution powder, and may be used by being dispersed / dissolved in water. That is, it may be prepared by mixing the powder for dispersion / dissolution with water.

-You may use the polishing composition of embodiment as said fine polishing composition.
In the polishing step, the used polishing composition may be collected and reused (circulated). For example, the above-described used polishing composition discharged from the polishing apparatus may be temporarily collected in a tank and supplied from the tank to the polishing apparatus again. In this case, since it is less necessary to treat the used polishing composition as a waste liquid, it is possible to reduce the environmental burden and the cost.

  Further, when the polishing composition is used in a circulating manner, a reduced amount of at least one of the components such as the abrasive in the polishing composition consumed or lost by being used for polishing the substrate material. You may make it perform replenishment. The components to be replenished may be added individually to the used polishing composition, or may be added to the used polishing composition in a mixture containing two or more components at any concentration.

-The said polishing composition can also be used for the use which grind | polishes materials other than a hard-brittle material.
Next, a technical idea that can be grasped from the embodiment will be described.
(A) The abrasive and the polishing composition used for polishing hard and brittle materials.

The embodiment will be described more specifically with reference to examples and comparative examples.
The polishing composition of Examples 1 to 4 and Comparative Example 1 was prepared by mixing a polishing material comprising zirconium oxide particles and oxide particles with water and adjusting the pH to 7 with phosphorous acid or potassium hydroxide. Prepared. Moreover, as Comparative Example 2, a polishing composition not containing oxide particles in an abrasive was prepared.

Details of the polishing composition of each example are shown in Table 1. The specific surface area in Table 1 indicates the specific surface area determined by the nitrogen adsorption method using FlowSorbII2300 manufactured by Shimadzu Corporation. The purity in Table 1 indicates the purity of zirconium oxide particles measured using Shimadzu Corporation XRF-1800. SiO ₂ and TiO ₂ in Table 1 indicate the contents of silicon dioxide and titanium dioxide contained in the zirconium oxide particles, respectively. The content of silicon dioxide and titanium dioxide was measured using ICPE-9000 manufactured by Shimadzu Corporation.

  The average primary particle diameter in Table 1 indicates a value of 50% particle diameter in a volume-based integrated fraction calculated based on a photograph taken with a scanning electron microscope. S-4700 manufactured by Hitachi High-Technologies Corporation was used as the scanning electron microscope, and Mac-View manufactured by Mountec Co., Ltd. was used as the image analysis apparatus. The average secondary particle diameter in Table 1 indicates a value of 50% particle diameter in a volume-based integrated fraction measured by LA-950 manufactured by Horiba, Ltd.

Table 2 shows details of the oxide particles contained in the polishing composition of each example. The column “average primary particle diameter” in Table 2 shows the average primary particle diameter calculated from the specific surface area measured by the nitrogen adsorption method using FlowSorbII2300 manufactured by Shimadzu Corporation and the mass. The “average secondary particle diameter” column in Table 2 indicates the 50% particle diameter in the volume-based integrated fraction determined by a laser diffraction / scattering particle diameter distribution measuring apparatus such as LA-950 manufactured by Horiba, Ltd. . The “mass ratio” column in Table 2 indicates the mass ratio of zirconium oxide particles to oxide particles contained in the abrasive.

Using the polishing composition of each example, the surface of an aluminosilicate glass substrate for a magnetic disk having a diameter of 65 mm (about 2.5 inches) was polished under the conditions shown in Table 3. Moreover, the surface of the alkali-free glass substrate for liquid crystal display glass of diameter 50mm (about 2 inches) was grind | polished on the conditions shown in Table 4 using the polishing composition of each example. And about the polishing composition of each example, the polishing rate and the surface defect were evaluated. The results are shown in Table 5.

  The “polishing rate” column in Table 5 shows the evaluation results for the polishing rate. “6” when the polishing rate obtained based on the difference in mass of the substrate before and after polishing is 0.6 μm / min or more, and “5” when it is 0.5 μm / min or more and less than 0.6 μm / min. "4" when 0.4 µm / min or more and less than 0.5 µm / min, "3" when 0.3 µm / min or more and less than 0.4 µm / min, 0.2 µm / min or more and 0.3 µm The case of less than / min was evaluated as “2”, and the case of less than 0.2 μm / min was evaluated as “1”.

  The “scratch” column in Table 5 shows the evaluation results for surface defects based on the number of scratches measured on the polished substrate. “5” when the number of scratches on the substrate surface measured using “Micro Max VMX-2100” manufactured by VISION PSYTEC is less than 20, “4” when the number of scratches is 20 or more and less than 100, and 100 or more and 200 The case of less than 300 was evaluated as “3”, the case of 200 or more and less than 300 as “2”, the case of 300 or more and less than 400 as “1”, and the case of 400 or more as “0”.

As shown in Table 5, in the polishing compositions of Examples 1 to 4, satisfactory results were obtained practically with respect to the polishing rate and surface defects (scratches). On the other hand, in the polishing compositions of Comparative Examples 1 and 2, satisfactory results were not obtained with respect to surface defects (scratches).

Claims (7)

An abrasive containing zirconium oxide particles,
An abrasive comprising at least one oxide particle selected from aluminum oxide particles and silicon oxide particles.   2. The abrasive according to claim 1, wherein the oxide particles are contained in a range of 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the zirconium oxide particles.   3. The abrasive according to claim 1, wherein an average primary particle diameter of the zirconium oxide particles is 0.3 μm or less.   4. The abrasive according to claim 1, wherein an average secondary particle diameter of the zirconium oxide particles is 0.1 μm or more and 5 μm or less. A polishing composition comprising the abrasive according to any one of claims 1 to 4 and water,
Polishing composition characterized by content of the said abrasive | polishing material being 0.1 mass% or more.   A method for polishing a hard and brittle material, comprising polishing a hard and brittle material using the polishing composition according to claim 5.   A method for producing a hard and brittle material substrate, comprising a polishing step of polishing a substrate material made of a hard and brittle material using the polishing composition according to claim 5.