JP2014120189A - Polishing liquid composition for magnetic disk substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing liquid composition for a magnetic disk substrate that can reduce defects in a substrate surface after polishing without impairing productivity, and to provide a method of producing and polishing a magnetic disk substrate using the same.SOLUTION: A polishing liquid composition for a magnetic disk substrate includes a polishing material, an acid, an oxidant, and a compound (A) having a molecular wight of 1,000 or less and having one or more amino group and one or more sulfonic acid group in one molecule, excluding sulfamic acid. The compound (A) includes preferably an aminobenzenesulfonic acid skeleton. A magnetic disk substrate to be polished is, for example, a magnetic disk substrate having an Ni-P containing layer.

Description

  The present invention relates to a polishing composition for a magnetic disk substrate and a method for producing a magnetic disk substrate using the same.

  In recent years, magnetic disk drives have been reduced in size and capacity, and high recording density has been demanded. For the purpose of increasing the recording density, in order to improve the detection sensitivity of a magnetic signal weakened by reducing the unit recording area, technological development for lowering the flying height of the magnetic head has been advanced. For magnetic disk substrates, in order to cope with low flying height of magnetic head and securing recording area, improvement of smoothness and flatness represented by reduction of surface roughness, waviness, end face sagging and scratches, protrusions, pits, etc. Demands for defect reduction represented by reduction of the level are becoming strict. In response to such a requirement, Patent Document 1 discloses a polishing composition containing a compound such as sulfamic acid.

  Moreover, the application is not an abrasive composition but a cleaning agent for a magnetic disk substrate. However, Patent Document 2 realizes a high cleanliness corresponding to a high recording density by improving the cleaning property against abrasive grains and polishing scraps. Therefore, a detergent containing a compound or a salt thereof having one or more amino acid groups and one or more sulfonic acid groups in one molecule is disclosed. Patent Document 3 describes a method of polishing a substrate having a noble metal using a sulfonic acid compound such as an alkyl sulfonic acid as a polishing aid, and Patent Document 4 describes a CMP abrasive containing a zwitterionic water-soluble organic low molecule. Patent Document 5 discloses a CMP abrasive containing a low molecular additive such as aniline, and Patent Document 6 discloses a complexing agent having one or more nitrogen atoms as donor atoms in the molecular structure, such as aminobenzenesulfonic acid. A surface treatment composition for silicon wafers is disclosed.

JP 2002-167575 A JP 2012-109004 A JP 2006-519490 A JP 2001-7059 A JP 2001-7061 A Japanese Patent Laid-Open No. 9-111224

  However, as the capacity of the magnetic disk drive is increased, the required characteristics for the surface quality of the substrate are becoming stricter, and the development of a polishing composition that can further reduce defects without impairing productivity is demanded.

  Therefore, the present invention provides a polishing composition for a magnetic disk substrate that can reduce defects on the surface of the substrate after polishing without impairing productivity, and a method for manufacturing and polishing a magnetic disk substrate using the same.

  In one aspect, the present invention is a compound having one or more amino groups and one or more sulfonic acid groups in one molecule, excluding abrasives, acids, oxidizing agents, and sulfamic acids, and having a molecular weight of 1000 or less. The polishing liquid composition for magnetic disk board | substrates containing (A).

  In another aspect of the present invention, the polishing composition for a magnetic disk substrate of the present invention is supplied to the surface to be polished of the substrate to be polished, the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or the above-mentioned The present invention relates to a method of manufacturing a magnetic disk substrate, including a step of moving a substrate to be polished to polish the surface to be polished.

  In another aspect of the present invention, the polishing composition for a magnetic disk substrate of the present invention is supplied to the surface to be polished of the substrate to be polished, the polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or the above-mentioned The present invention relates to a method for polishing a magnetic disk substrate, including a step of moving a substrate to be polished and polishing the surface to be polished.

  By using the polishing composition for a magnetic disk substrate of the present invention, a magnetic disk substrate with reduced defects on the surface of the substrate after polishing can be produced without impairing productivity.

  The present invention contains a compound (A) having a molecular weight of 1000 or less and having one or more amino groups and one or more sulfonic acid groups in one molecule (hereinafter also referred to as “compound (A)”). If the polishing composition is used for the production of a magnetic disk substrate, it is based on the knowledge that defects on the substrate surface after polishing can be reduced without impairing productivity.

  That is, the present invention relates to a compound having a molecular weight of 1000 or less (excluding an abrasive, an acid, an oxidizing agent, and sulfamic acid) and having one or more amino groups and one or more sulfonic acid groups in the molecule (A ) Containing a polishing composition for a magnetic disk substrate (hereinafter also referred to as “the polishing composition of the present invention”).

  In the polishing liquid composition of the present invention, details of the mechanism for reducing defects on the substrate surface after polishing without impairing productivity are not clear, but the inventor presumes the following. However, the present invention is not limited to the following mechanism.

  In general, abrasive particles (polishing material) used for polishing a substrate to be polished, silica particles, alumina particles, and the like are positively charged depending on the liquid property at the time of polishing, and are easily adsorbed on the surface of the substrate to be negatively charged. Causes protrusion defects. However, the strongly negatively charged sulfonic acid group of the compound (A) having a sulfonic acid group and an amino group (hereinafter sometimes abbreviated as “compound (A)”) is adsorbed to the positively charged abrasive grains. Thus, the adsorption of abrasive grains to the negatively charged substrate is suppressed by electrostatic repulsion. On the other hand, the amino group of the compound (A) is attracted to the vicinity of the negatively charged substrate to be polished. That is, positively charged abrasive grains act on the negatively charged substrate to be polished via the compound (A), so that productivity is not impaired and defects on the substrate surface after polishing are reduced. it is conceivable that.

  The substrate to be polished, which is a polishing target of the polishing composition for a magnetic disk substrate of the present invention, is not particularly limited, but the polishing composition for a magnetic disk substrate of the present invention is particularly for the following reasons: It is suitable for polishing an aluminum substrate on which Ni-P plating has been applied.

  When the polishing composition for a magnetic disk substrate of the present invention is used for polishing an aluminum substrate plated with Ni-P, Ni which is polishing scrap generated during polishing is oxidized and is one of Ni-based foreign matters. NiO particles are produced. Since the NiO particles are positively charged under acidic conditions, which are general polishing conditions, when the compound (A) is contained in the polishing composition of the present invention, the strongly negatively charged sulfonic acid groups Is adsorbed to the NiO particles, whereby the adsorption of the NiO particles to the negatively charged Ni-P-containing layer is suppressed by charge repulsion. And after rinsing under acidic conditions, when rinsing and cleaning the polished aluminum substrate, the liquidity supplied to the aluminum substrate changes from acidic to neutral or alkaline, so that the NiO particles As the surface exceeds the isoelectric point, the positively charged surface becomes negatively charged. As a result, the compound (A) is detached from the NiO particles, and due to charge repulsion between the negatively charged NiO particles and the negatively charged Ni-P-containing layer, the NiO particles as polishing scraps are transferred to the Ni-P-containing layer. Since the adhesion is also suppressed, the cleaning property of the aluminum substrate is improved. As a result, when the polishing composition for a magnetic disk substrate according to the present invention is used for polishing an Ni-P plated aluminum substrate, defects on the surface of the substrate after polishing are observed without particularly impairing productivity. It is estimated that can be reduced.

[Compound (A)]
The compound (A) contained in the polishing liquid composition of the present invention has a molecular weight of 1000 or less, and has one or more amino groups and one or more sulfonic acid groups in one molecule. The compound (A) functions as an agent for preventing an abrasive such as alumina particles from adhering to the substrate to be polished. Further, when the substrate to be polished is a substrate subjected to Ni-P plating, the compound (A) functions as an agent for preventing adhesion of Ni-based foreign matters such as NiO particles to the substrate. In addition, in this invention, a compound (A) is the concept containing the salt.

  In the present application, the type of the salt of the compound (A) is not particularly limited, and examples thereof include alkali metal salts such as sodium salt and potassium salt, ammonium salts, and organic amine salts. From the viewpoint of general aggregation suppression, at least one of an alkali metal salt and an ammonium salt is preferable.

(Molecular weight of compound (A))
The molecular weight of the compound (A) is 1000 or less, preferably 900 or less, more preferably 500 or less, from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. . In addition, the molecular weight of the compound (A) is preferably 30 or more, more preferably 50 or more, and still more preferably 80 or more, from the viewpoint of reducing defects in the substrate after polishing.

  The compound (A) is a compound having an amino group and a sulfonic acid group in one molecule and having a molecular weight of 1000 or less. Specifically, sulfanilic acid (p-aminobenzenesulfonic acid), o-aminobenzene Sulfonic acid (2-aminobenzenesulfonic acid), methanylic acid (m-aminobenzenesulfonic acid or 3-aminobenzenesulfonic acid), 3-amino-4-hydroxybenzenesulfonic acid, 6-aminotoluene-3-sulfonic acid; Amino such as diphenylamine-4-sulfonic acid, 2-aminotoluene-4-sulfonic acid, 4-aminotoluene-2-sulfonic acid, 2-aminophenol-4-sulfonic acid, and 4-aminophenol-2-sulfonic acid Compounds having aryl sulfonic acid groups such as benzene sulfonic acid and pyridine ethane sulfonic acid, cyclohexylamino Tan sulfonic acid, N- tris (hydroxymethyl) methyl-2-aminoethanesulfonic acid, and taurine, and the like. Among these, the compound (A) is more preferable to have an arylsulfonic acid group from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. More preferably, it has an aminobenzenesulfonic acid skeleton, and is at least selected from the group consisting of sulfanilic acid (p-aminobenzenesulfonic acid), o-aminobenzenesulfonic acid, and methanyl acid (m-aminobenzenesulfonic acid). One type is more preferable.

  The content of the compound (A) in the polishing liquid composition of the present invention is 0.3 mass from the viewpoint of ensuring the polishing rate so as not to impair the productivity and from the viewpoint of reducing defects on the substrate surface after polishing. % Or less, more preferably 0.15% by mass or less, still more preferably 0.08% by mass or less, still more preferably 0.05% by mass or less, and even more preferably 0.04% by mass or less. Further, the content of the compound (A) is preferably 0.005% by mass or more, more preferably 0.008% by mass or more, and 0.01% by mass or more from the viewpoint of reducing defects on the substrate surface after polishing. More preferred is 0.02% by mass or more.

[Abrasive]
As the abrasive used in the polishing composition of the present invention, silicon oxide (silica), aluminum oxide (alumina), cerium oxide (ceria), titanium oxide (titania), zirconium oxide (zirconia), germania, nitriding Abrasive particles containing one or more materials selected from the group consisting of silicon and silicon carbide are suitable for polishing precision component substrates such as magnetic disk substrates, but ensure the polishing rate so as not to impair productivity. However, from the viewpoint of reducing defects on the substrate surface after polishing, at least one of silica, alumina, and ceria is preferable, colloidal silica, colloidal ceria, and colloidal alumina are more preferable, and colloidal silica is more preferable.

[Average particle size of abrasive]
The “average particle diameter of the abrasive” in the present specification means an average particle diameter based on a scattering intensity distribution measured at a detection angle of 90 ° in the dynamic light scattering method (hereinafter referred to as “scattering intensity” unless otherwise specified). Also referred to as “average particle size based on distribution”). The average particle size of the abrasive is preferably 1 nm or more, more preferably 5 nm or more, still more preferably 10 nm or more, and even more preferably 15 nm or more from the viewpoint of reducing defects on the substrate surface after polishing. The average particle size of the abrasive is preferably 40 nm or less, more preferably 37 nm or less, still more preferably 35 nm or less, and even more preferably 30 nm or less from the viewpoint of ensuring the polishing rate so as not to impair the productivity. The average particle size of the abrasive can be specifically obtained by the method described in the examples.

  The ΔCV value of the abrasive is preferably 0.05% or more, more preferably 0.1% or more, still more preferably 0.5% or more, from the viewpoint of ensuring the polishing rate so as not to impair the productivity. 0.0% or more is more preferable, and 2.0% or more is more preferable. The ΔCV value is preferably 12% or less, more preferably 10% or less, still more preferably 7% or less, and even more preferably 5% or less, from the viewpoint of reducing defects on the substrate surface after polishing.

[ΔCV value]
In this specification, the ΔCV value of the abrasive is the standard deviation of the particle diameter measured based on the scattering intensity distribution at a detection angle of 30 ° (forward scattering) by the dynamic light scattering method, and the detection angle of 30 by the dynamic light scattering method. Scattering with a coefficient of variation (CV30) multiplied by 100 divided by the average particle diameter measured based on the scattering intensity distribution of ° C (CV30) and a detection angle of 90 ° (side scattering) by the dynamic light scattering method A coefficient of variation (CV90) obtained by dividing the standard deviation of the particle diameter measured based on the intensity distribution by the average particle diameter measured based on the scattering intensity distribution at a detection angle of 90 ° by the dynamic light scattering method and multiplying by 100. ) (ΔCV = CV30−CV90) and a value indicating the angular dependence of the scattering intensity distribution measured by the dynamic light scattering method. Specifically, the ΔCV value can be measured by the method described in Examples.

  The method of adjusting the particle size distribution of the abrasive is not particularly limited, but a method of giving a desired particle size distribution by adding new core particles in the particle growth process in the production stage, or a different particle size Examples thereof include a method of mixing two or more kinds of abrasives having a distribution to give a desired particle size distribution.

  The content of the abrasive in the polishing composition of the present invention is preferably 0.5% by mass or more, more preferably 1% by mass or more, from the viewpoint of ensuring the polishing rate so as not to impair the productivity. % Or more is more preferable, 3 mass% or more is further more preferable, and 4 mass% or more is still more preferable. The content of the abrasive is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 13% by mass or less, and more preferably 10% by mass or less from the viewpoint of reducing defects on the substrate surface after polishing. More preferably, 7 mass% or less is still more preferable.

[acid]
The polishing composition of the present invention contains an acid from the viewpoint of improving the polishing rate. In the present invention, the use of an acid includes the use of an acid and / or a salt thereof. Examples of the acid used in the polishing liquid composition of the present invention include nitric acid, sulfuric acid, sulfurous acid, persulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, orthophosphoric acid, polyphosphoric acid, and tripolyphosphoric acid. Inorganic acids such as dipotassium hydrogen phosphate and amidosulfuric acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotri (methylenephosphonic acid) (ATMP), ethylenediaminetetra (methylenephosphone) Acid), diethylenetriaminepenta (methylenephosphonic acid), ethane-1,1, -diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxy -1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid Organic phosphonic acids such as methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, α-methylphosphonosuccinic acid, glutamic acid, picolinic acid, aspartic acid, etc. Examples thereof include carboxylic acids such as aminocarboxylic acid, citric acid, tartaric acid, oxalic acid, nitroacetic acid, maleic acid, and oxaloacetic acid, and organic sulfonic acids such as sulfosalicylic acid. Of these, inorganic acids, organic phosphonic acids, and organic sulfonic acids are preferable from the viewpoint of reducing defects on the substrate surface after polishing. Among inorganic acids, nitric acid, sulfuric acid, hydrochloric acid, perchloric acid, and phosphoric acid are preferable, phosphoric acid such as orthophosphoric acid, polyphosphoric acid, and dipotassium hydrogen phosphate, and sulfuric acid are more preferable, and sulfuric acid is more preferable. Among the organic phosphonic acids, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and salts thereof are preferable. Hydroxyethylidene-1,1-diphosphonic acid and aminotri (methylenephosphonic acid) are more preferred. Of the organic sulfonic acids, sulfosalicylic acid is preferred.

  The acids may be used alone or in admixture of two or more, but from the viewpoint of improving the polishing rate and improving the cleaning property of the substrate, it is preferable to use a mixture of two or more, reducing defects, oxidizing agent Selected from the group consisting of phosphoric acid, sulfuric acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), and sulfosalicylic acid It is more preferable to use a mixture of the above acids, and one or more acids selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), and sulfosalicylic acid, and sulfuric acid; It is still more preferable to mix and use.

  The salt of the acid salt is not particularly limited, and specific examples include salts with metals, ammonium, alkylammonium and the like. Specific examples of the metal include metals belonging to the periodic table (long-period type) 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8. Among these, from the viewpoint of reducing defects on the substrate surface after polishing, a metal belonging to Group 1A or a salt with ammonium is preferable.

  The content of the acid and the salt thereof in the polishing composition is 0.001% by mass or more from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. Preferably, 0.01 mass% or more is more preferable, 0.05 mass% or more is further preferable, 0.1 mass% or more is further more preferable, and 0.4 mass% or more is still more preferable. The content of the acid and the salt thereof is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, still more preferably 3.0% by mass or less, and further more preferably 2.0% by mass or less. Preferably, 1.0 mass% or less is still more preferable.

[Oxidant]
The polishing composition of the present invention contains an oxidizing agent from the viewpoint of improving the polishing rate and reducing defects on the substrate surface after polishing. Examples of the oxidizing agent that can be used in the polishing liquid composition of the present invention include peroxide, permanganic acid or a salt thereof, chromic acid or a salt thereof, peroxo acid or a salt thereof, oxygen acid or a salt thereof, and metal salts. .

  Examples of the peroxide include hydrogen peroxide, sodium peroxide, barium peroxide, etc., examples of the permanganic acid or salt thereof include potassium permanganate, and examples of the chromic acid or salt thereof include chromium. Acid metal salts, metal dichromates, and the like. Peroxo acids or salts thereof include peroxodisulfuric acid, ammonium peroxodisulfate, peroxodisulfate metal salts, peroxophosphoric acid, peroxosulfuric acid, sodium peroxoborate, and performic acid. Peroxyacetic acid, perbenzoic acid, perphthalic acid, etc., and oxygen acids or salts thereof include hypochlorous acid, hypobromite, hypoiodous acid, chloric acid, bromic acid, iodic acid, hypochlorous acid. Examples include sodium chlorate, calcium hypochlorite, and metal salts include iron (III) chloride, iron (III) nitrate, iron (III) sulfate, and iron citrate. III), ammonium iron (III), and the like.

  Preferred oxidizing agents from the viewpoint of reducing defects on the substrate surface after polishing include hydrogen peroxide, iron (III) nitrate, peracetic acid, ammonium peroxodisulfate, iron (III) sulfate, and iron (III) ammonium sulfate. . As a more preferable oxidizing agent, hydrogen peroxide is mentioned from the viewpoint that metal ions do not adhere to the surface and are generally used and inexpensive. These oxidizing agents may be used alone or in admixture of two or more.

  The content of the oxidizing agent in the polishing liquid composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, further preferably 0.1% by mass or more, from the viewpoint of improving the polishing rate. From the viewpoint of reducing defects on the substrate surface after polishing, it is preferably 4% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by mass or less.

[water]
Water in the polishing composition of the present invention is used as a medium, and examples thereof include distilled water, ion exchange water, and ultrapure water. From the viewpoint of improving the cleaning of the surface of the substrate to be polished, the water is preferably ion-exchanged water or ultrapure water, more preferably ultrapure water. 76-99.4 mass% is preferable and, as for content of water in polishing liquid composition, 80-98.9 mass% is more preferable. Moreover, within the range which does not inhibit the effect of this invention, the polishing liquid composition of this invention may further contain organic solvents, such as alcohol.

[Other ingredients]
The polishing liquid composition of the present invention may contain other components as necessary. Examples of other components include a metal anticorrosive, a water-soluble polymer having an anionic group having no amino group, a thickener, a dispersant, a rust inhibitor, a basic substance, and a surfactant. 0-10 mass% is preferable and, as for the total content of these other arbitrary components in polishing liquid composition, 0-5 mass% is more preferable. Furthermore, the polishing composition of the present invention can contain alumina abrasive grains, and can also be used in the rough polishing step prior to the final polishing step.

  Next, specific examples of the metal anticorrosive and the water-soluble polymer having no amino group will be described.

[Metal anticorrosive]
The polishing composition of the present invention preferably contains a heterocyclic aromatic compound as a metal anticorrosive from the viewpoint of reducing defects on the substrate surface after polishing. By coating a portion susceptible to corrosion with a metal anticorrosive film, defects on the substrate surface after polishing are reduced. From the viewpoint of reducing defects on the substrate surface after polishing, the heterocyclic aromatic compound preferably has 2 or more nitrogen atoms contained in the heterocyclic ring, more preferably 3 or more, It is more preferable that it is 9, 3 to 5 is even more preferable, and 3 or 4 is still more preferable.

  From the viewpoint of reducing defects on the substrate surface after polishing, the heterocyclic aromatic compound is a 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole. 1,2,5-thiadiazole, 1,3,4-thiadiazole, 3-aminopyrazole, 4-aminopyrazole, 3,5-dimethylpyrazole, pyrazole, 2-aminoimidazole, 4-aminoimidazole, 5-aminoimidazole 2-methylimidazole, 2-ethylimidazole, imidazole, benzimidazole, 1,2,3-triazole, 4-amino-1,2,3-triazole, 5-amino-1,2,3-triazole, 1,2, 4-triazole, 3-amino-1,2,4-triazole, 5-amino-1,2,4-triazole, 3-mercap To-1,2,4-triazole, 1H-tetrazole, 5-aminotetrazole, 1H-benzotriazole, 1H-tolyltriazole, 2-aminobenzotriazole, 3-aminobenzotriazole, or alkyl substituents or amines thereof Azoles such as substituted; pyrimidine, pyrazine, pyridazine, 1,2,3-triazine, 1,2,4-triazine, 1,2,5-triazine, 1,3,5-triazine, or alkyl thereof A substituted or amine-substituted product is preferred, azoles are more preferred, and 1,2,3-triazole, 1,2,4-triazole, and benzotriazole are more preferred. Moreover, as an alkyl group of the said alkyl substituted body, a C1-C4 lower alkyl group is mentioned, More specifically, a methyl group and an ethyl group are mentioned. Examples of the amine-substituted product include 1- [N, N-bis (hydroxyethylene) aminomethyl] benzotriazole and 1- [N, N-bis (hydroxyethylene) aminomethyl] tolyltriazole.

  The content of the metal anticorrosive in the polishing composition of the present invention is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, from the viewpoint of reducing defects on the substrate surface after polishing. 0.05% by mass or more is more preferable, 0.07% by mass or more is more preferable, and 0.08% by mass or more is further more preferable. In addition, the content of the metal anticorrosive is preferably 10% by mass or less and more preferably 5% by mass or less from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. It is preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, and still more preferably 0.3% by mass or less. In addition, the heterocyclic aromatic compound in the polishing composition may be one kind or two or more kinds.

[Water-soluble polymer having an anionic group having no amino group]
From the viewpoint of reducing defects on the surface of the substrate after polishing, the polishing composition of the present invention has a high water-solubility having an anionic group that does not have an amino group, while ensuring a polishing rate so as not to impair productivity. Molecules (hereinafter also referred to as “anionic water-soluble polymer”) may be further included. Here, “water-soluble” means that the solubility in 100 g of water at 20 ° C. is 2 g or more. It is presumed that the anionic water-soluble polymer reduces defects on the substrate surface by reducing frictional vibration during polishing and preventing the abrasive from falling off from the opening of the polishing pad.

  Examples of the anionic group of the water-soluble polymer having an anionic group having no amino group include a carboxylic acid group, a sulfonic acid group, a sulfate ester group, a phosphate ester group, and a phosphonic acid group. These anionic groups may be in the form of a salt. A water-soluble polymer having an anionic group not having an amino group is a sulfonic acid group and a carboxylic acid group from the viewpoint of reducing defects on the surface of the substrate after polishing while ensuring the polishing rate so as not to impair the productivity. An anionic polymer having at least one of these is preferable, and an anionic polymer having a sulfonic acid group is more preferable.

  The salt in the case where the anionic group is a salt is not particularly limited, and specific examples include salts with metals, ammonium, alkylammonium and the like. Specific examples of the metal include metals belonging to the periodic table (long-period type) 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8. Specific examples of alkylammonium include tetramethylammonium, tetraethylammonium, tetrabutylammonium and the like. Among these, the salt when the anionic group is a salt is a group of 1A, 3B, or 8 from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. A salt with a metal or ammonium belonging to the group 1 is preferred, a salt with a metal or ammonium belonging to Group 1A is more preferred, and a salt with ammonium, sodium or potassium is more preferred.

  The water-soluble polymer having an anionic group not having an amino group according to the present invention is obtained by polymerizing a monomer having an anionic group such as a monomer having a sulfonic acid group or a monomer having a carboxylic acid group. Can be obtained. The arrangement of these monomers may be random, block, or graft, but random is preferable from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. .

  As a suitable example of the water-soluble polymer having an anionic group having no amino group of the present invention, while ensuring the polishing rate so as not to impair the productivity, from the viewpoint of reducing defects on the substrate surface after polishing, A polymer containing a structural unit derived from a monomer having a sulfonic acid group shown below or a salt thereof is preferable.

  Specific examples of the monomer having a sulfonic acid group include isoprene sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, styrene sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid, iso Examples include amylene sulfonic acid and naphthalene sulfonic acid. Examples of the monomer having a carboxylic acid group include itaconic acid, (meth) acrylic acid, maleic acid and the like. Examples of the monomer having a phosphate ester group or a phosphonic acid group include vinylphosphonic acid, methacryloyloxymethyl phosphoric acid, methacryloyloxyethyl phosphoric acid, methacryloyloxybutyl phosphoric acid, methacryloyloxyhexyl phosphoric acid, Examples include methacrylyloxyoctyl phosphoric acid, methacrylyloxydecyl phosphoric acid, methacryloyloxylauryl phosphoric acid, metalloyloxystearyl phosphoric acid, methacryloyloxy 1,4-dimethylcyclohexylphosphoric acid. Among these, 2- (meth) acrylamido-2-methylpropanesulfonic acid is preferable from the viewpoint of reducing defects on the substrate surface after polishing while ensuring a polishing rate so as not to impair productivity.

  Further, the water-soluble polymer having an anionic group having no amino group in the present invention may contain a structural unit derived from a monomer other than the above. Examples of other monomers include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and p-methylstyrene, unsaturated carboxylic acids such as (meth) acrylic acid, methyl (meth) acrylate, Fats such as (meth) acrylic acid alkyl esters such as ethyl (meth) acrylate and octyl (meth) acrylate, butadiene, isoprene, 2-chloro-1,3-butadiene, 1-chloro-1,3-butadiene and the like And vinyl cyanide compounds such as group conjugated dienes and (meth) acrylonitrile. Among these, (meth) acrylic acid is preferable from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. Therefore, a copolymer of (meth) acrylic acid and 2- (meth) acrylamide-2-methylpropanesulfonic acid is preferable as the water-soluble polymer having an anionic group having no amino group in the present invention.

  As another preferred example of the water-soluble polymer having an anionic group having no amino group in the present invention, it has a sulfonic acid group and has an aromatic ring in each of its main chain and side chain. Preferred are water-soluble polymers. A compound having a sulfonic acid group and a compound capable of introducing an aromatic ring into both the main chain and side chain of a water-soluble polymer having an anionic group not having an amino group, in the presence of formaldehyde, etc. It can manufacture by superposing | polymerizing by the well-known means of these. Specifically, the compound currently disclosed by Unexamined-Japanese-Patent No. 2012-135863 is mentioned. Among other suitable examples of the water-soluble polymer having an anionic group not having the amino group, from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. A formaldehyde addition condensate of bis (4-hydroxyphenyl) sulfone and 4-hydroxybenzenesulfonic acid is preferred.

  In the present invention, the weight average molecular weight of the water-soluble polymer having an anionic group that does not have an amino group is from the viewpoint of reducing defects on the substrate surface after polishing while ensuring the polishing rate so as not to impair the productivity. 500-100,000 are preferable, More preferably, it is 1000-50,000, More preferably, it is 1500-30,000, More preferably, it is 1500-20,000. For example, the weight average molecular weight can be determined using gel permeation chromatography (GPC).

  The content of the water-soluble polymer having an anionic group having no amino group in the polishing liquid composition of the present invention is preferably 0.001% by mass or more from the viewpoint of reducing defects on the substrate surface after polishing. 0.002 mass% or more is more preferable, 0.005 mass% or more is still more preferable, and 0.008 mass% or more is still more preferable. From the viewpoint of reducing defects on the substrate surface after polishing, while ensuring the polishing rate so as not to impair productivity, it is preferably 0.1% by mass or less, more preferably 0.08% by mass or less, and 0.05% by mass. % Or less is still more preferable, and 0.03 mass% or less is still more preferable.

[PH of polishing composition]
The pH of the polishing composition of the present invention is preferably 4.0 or less, more preferably 3.5 or less, still more preferably 3.0 or less, even more preferably 2.5 or less, from the viewpoint of improving the polishing rate. Even more preferred is 2.0 or less. Further, from the viewpoint of reducing defects on the substrate surface after polishing, 0.5 or more is preferable, 0.8 or more is more preferable, 1.0 or more is further preferable, and 1.2 or more is even more preferable.

[Method for preparing polishing liquid composition]
The polishing liquid composition of the present invention has, for example, water, an abrasive, an acid, an oxidizing agent, a compound (A), a metal anticorrosive, and an anionic group having no amino group, if desired. It can be prepared by mixing with other components such as a water-soluble polymer by a known method. At this time, the abrasive may be mixed with other components in a concentrated slurry state, or may be mixed with other components after the slurry is diluted with water or the like. Although preferable content and density | concentration of each component in the polishing liquid composition of this invention are the ranges mentioned above, you may prepare the polishing liquid composition of this invention as a concentrate as another aspect. In this case, it is preferable from the viewpoint of economy such that the manufacturing and transportation costs can be further reduced. The concentrate may be used after appropriately diluted with the above-mentioned aqueous medium as necessary. The concentration ratio is not particularly limited as long as the concentration at the time of polishing after dilution can be ensured, but is preferably 1.5 times or more from the viewpoint of economy such as further reduction in production and transportation costs. More than double, more preferably 4 times or more, more preferably 25 times or less, more preferably 20 times or less, and still more preferably 10 times or less.

  The polishing composition of the present invention is suitable for polishing a magnetic disk substrate.

  Examples of the material of the substrate to be polished preferably used in the present invention include metals, metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, or alloys thereof, glass, glassy carbon, and amorphous carbon. Examples thereof include glassy materials such as polyimide resins and the like. Among these, the polishing liquid composition of the present invention is suitable for polishing a substrate to be polished containing a metal such as aluminum, nickel, tungsten, or copper and an alloy containing these metals as a main component. Among these, the polishing composition of the present invention is suitable for polishing a substrate having a Ni—P-containing layer such as a Ni—P plated aluminum alloy substrate or an aluminosilicate glass substrate, and is a Ni—P plated aluminum. It is further suitable for polishing a substrate having a Ni—P containing layer such as an alloy substrate. Aluminosilicate glass substrates include those having a crystal structure and those subjected to chemical strengthening treatment. You may perform a chemical strengthening process after grinding | polishing.

[Substrate manufacturing method]
As another aspect, the present invention relates to a substrate manufacturing method (hereinafter, also referred to as “the manufacturing method of the present invention”). In the production method of the present invention, the polishing liquid composition for a magnetic disk substrate is supplied to the surface to be polished of the substrate to be polished, the polishing pad is brought into contact with the surface to be polished, the polishing pad and / or the substrate to be polished is moved, This is a method for producing a substrate including a step of polishing a surface to be polished (hereinafter also referred to as “polishing step using the polishing composition of the present invention”). Thereby, the board | substrate with which the defect of the board | substrate surface after grinding | polishing was reduced can be provided. The manufacturing method of the present invention is suitable for a method of manufacturing a magnetic disk substrate, and particularly suitable for a method of manufacturing a magnetic disk substrate for a perpendicular magnetic recording system having a Ni—P containing layer. Therefore, as another aspect, the production method of the present invention is a method for producing a magnetic disk substrate including a polishing step using the polishing composition of the present invention, and more preferably production of a magnetic disk substrate for perpendicular magnetic recording system. A method of manufacturing a magnetic disk substrate having a Ni-P-containing layer.

  As a specific example of a method for polishing a substrate to be polished using the polishing liquid composition of the present invention, the substrate to be polished is sandwiched between a surface plate to which a polishing pad such as a non-woven organic polymer polishing cloth is attached. A method of polishing the substrate to be polished by moving the surface plate or the substrate to be polished while supplying the polishing composition of the invention to the polishing machine can be mentioned.

  In the case where the polishing process of the substrate to be polished is performed in multiple stages, the polishing process using the polishing composition of the present invention is preferably performed in the second stage and more preferably in the final polishing process. At that time, in order to avoid mixing of the polishing material and polishing liquid composition in the previous process, different polishing machines may be used, and in the case of using different polishing machines, polishing is performed for each polishing process. It is preferable to clean the substrate. Further, the polishing composition of the present invention can also be used in cyclic polishing that reuses the used polishing composition. The polishing machine is not particularly limited, and a known polishing machine for substrate polishing can be used.

[Polishing pad]
The polishing pad used in the present invention is not particularly limited, and a polishing pad of a suede type, a nonwoven fabric type, a polyurethane closed-cell foam type, or a two-layer type in which these are laminated can be used. From the viewpoint of improvement, a suede type polishing pad is preferable.

  The average opening diameter of the surface member of the polishing pad is preferably 50 μm or less, more preferably 45 μm or less, still more preferably 40 μm or less, and still more preferably, from the viewpoint of reducing defects on the substrate surface after polishing and extending the life of the pad. 35 μm or less. From the viewpoint of holding the polishing liquid of the pad, the average opening diameter is preferably 0.01 μm or more, more preferably 0.1 μm or more, and still more preferably in order to keep the polishing liquid in the openings and prevent the liquid from running out. Is 1 μm or more, and more preferably 10 μm or more. Further, the maximum value of the opening diameter of the polishing pad is preferably 100 μm or less, more preferably 70 μm or less, still more preferably 60 μm or less, and particularly preferably 50 μm or less from the viewpoint of maintaining the polishing rate.

[Polishing load]
The polishing load in the polishing step using the polishing liquid composition of the present invention is preferably 5.0 kPa or more, more preferably 6.5 kPa or more, still more preferably 7.0 kPa or more, from the viewpoint of suppressing a decrease in polishing rate. 7.5 kPa or more is still more preferable. In the production method of the present invention, the polishing load refers to the pressure of the surface plate applied to the polishing surface of the substrate to be polished during polishing. In the polishing step using the polishing liquid composition of the present invention, the polishing load is preferably 20 kPa or less, more preferably 18 kPa or less, still more preferably 16 kPa or less, from the viewpoint of reducing defects on the substrate surface after polishing. The following is even more preferable. The polishing load can be adjusted by applying air pressure or weight to at least one of the surface plate and the substrate to be polished.

[Supply of polishing liquid composition]
The supply rate of the polishing composition of the present invention in the polishing step using the polishing composition of the present invention is preferably 0.05 mL per 1 cm ^{2 of the} substrate to be polished from the viewpoint of reducing defects on the substrate surface after polishing. / Min., More preferably 0.06 mL / min or more, further preferably 0.07 mL / min or more, preferably 15 mL / min or less, more preferably 10 mL / min or less, still more preferably 1 mL / min. Min or less, even more preferably 0.5 mL / min or less.

  As a method for supplying the polishing composition of the present invention to a polishing machine, for example, a method of continuously supplying using a pump or the like can be mentioned. When supplying the polishing composition to the polishing machine, in addition to the method of supplying one component containing all the components, considering the stability of the polishing composition, etc., it is divided into a plurality of compounding component liquids, Two or more liquids can be supplied. In the latter case, for example, the plurality of compounding component liquids are mixed in the supply pipe or on the substrate to be polished to obtain the polishing liquid composition of the present invention.

  Examples of the substrate to be polished in the production method of the present invention include the substrate to be polished in which the polishing composition of the present invention is used. According to the present invention, it is possible to provide a substrate with reduced defects on the surface of the substrate after polishing. Therefore, the present invention is suitable for manufacturing a magnetic disk substrate that requires a high degree of surface smoothness, especially a perpendicular magnetic recording type magnetic disk substrate. Can be used.

  There is no restriction | limiting in particular in the shape of the said to-be-polished substrate, For example, what is necessary is just the shape which has planar parts, such as a disk shape, plate shape, slab shape, prism shape, and the shape which has curved surface parts, such as a lens. Of these, a disk-shaped substrate to be polished is suitable. In the case of a disk-shaped substrate to be polished, the outer diameter is about 2 to 95 mm, the inner diameter is about 1 to 90 mm, and the thickness is about 0.5 to 2 mm, for example.

[Polishing method]
In another aspect of the present invention, the polishing composition described above is supplied to the surface to be polished of the substrate to be polished, the polishing pad is brought into contact with the surface to be polished, the polishing pad and / or the substrate to be polished is moved, and polishing is performed. The present invention relates to a polishing method for a substrate to be polished, including a step of polishing a target surface. By using the polishing method of the present invention, a substrate with reduced defects on the surface of the substrate after polishing is provided. Examples of the substrate to be polished in the polishing method of the present invention include the above-described magnetic disk substrate, and among them, a magnetic disk substrate for perpendicular magnetic recording system is preferable. The specific polishing method and conditions can be as described above.

  The present invention further discloses the following polishing composition for a magnetic disk substrate, a method for producing a magnetic disk substrate, and a method for polishing a magnetic disk substrate.

<1>
A magnetic material containing an abrasive, an acid, an oxidizing agent, and a compound (A) having a molecular weight of 1000 or less and having one or more amino groups and one or more sulfonic acid groups in one molecule, excluding abrasives, acids, oxidizing agents, and sulfamic acids. Polishing liquid composition for disk substrates.
<2>
The polishing composition for a magnetic disk substrate according to <1>, wherein the substrate to be polished is preferably a magnetic disk substrate having a Ni—P-containing layer.
<3>
The pH of the magnetic disk substrate polishing liquid composition is preferably 0.5 or more and 4.0 or less, more preferably 3.5 or less, still more preferably 3.0 or less, and even more preferably 2.5 or less. 2.0 or less is more preferable, 0.8 or more is more preferable, 1.0 or more is more preferable, and 1.2 or more is even more preferable, for the magnetic disk substrate according to the above <1> or <2> Polishing liquid composition.
<4>
The content of the compound (A) in the polishing composition for a magnetic disk substrate is preferably 0.3% by mass or less, more preferably 0.15% by mass or less, and 0.08% by mass or less. Is more preferably 0.05% by mass or less, still more preferably 0.04% by mass or less, preferably 0.005% by mass or more, more preferably 0.008% by mass or more, and 0.01% by mass. The above-described polishing composition for a magnetic disk substrate according to any one of <1> to <3>, wherein the above is more preferable, and 0.02% by mass or more is even more preferable.
<5>
<1> to <4>, wherein the abrasive is abrasive particles containing one or more materials selected from the group consisting of silica, alumina, ceria, titania, zirconia, germania, silicon nitride, and silicon carbide. The polishing composition for a magnetic disk substrate according to any one of the above.
<6>
The polishing composition for a magnetic disk substrate according to any one of <1> to <5>, wherein the abrasive is colloidal silica.
<7>
The average particle size of the abrasive is preferably 1 nm or more, more preferably 5 nm or more, further preferably 10 nm or more, still more preferably 15 nm or more, preferably 40 nm or less, more preferably 37 nm or less, still more preferably 35 nm or less, The polishing composition for a magnetic disk substrate according to any one of <1> to <6>, wherein 30 nm or less is even more preferable.
<8>
The ΔCV value of the abrasive is preferably 0.05% or more, more preferably 0.1% or more, further preferably 0.5% or more, still more preferably 1.0% or more, and 2.0% or more. More preferably, 12% or less, more preferably 10% or less, still more preferably 7% or less, and even more preferably 5% or less, for the magnetic disk substrate according to any one of <1> to <7> Polishing liquid composition.
<9>
The content of the abrasive in the polishing composition for a magnetic disk substrate is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 2% by mass or more, and more preferably 3% by mass or more. Still more preferably, 4% by mass or more is more preferable, 20% by mass or less is preferable, 15% by mass or less is more preferable, 13% by mass or less is further preferable, 10% by mass or less is further more preferable, and 7% by mass or less is preferable. The magnetic disk substrate polishing liquid composition according to any one of <1> to <8>, which is still more preferable.
<10>
The acid is selected from the group consisting of sulfuric acid, orthophosphoric acid, polyphosphoric acid, dipotassium hydrogen phosphate, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotri (methylenephosphonic acid) (ATMP), and sulfosalicylic acid. The polishing composition for a magnetic disk substrate according to any one of <1> to <9>, wherein the polishing liquid composition is at least one acid.
<11>
The magnetic disk substrate polishing liquid composition according to any one of <1> to <10>, wherein the magnetic disk substrate polishing liquid composition further contains a metal anticorrosive.
<12>
The polishing composition for a magnetic disk substrate according to <11>, wherein the metal anticorrosive is an azole.
<13>
The magnetic disk according to <11> or <12>, wherein the metal anticorrosive is at least one selected from the group consisting of benzotriazole, 1,2,3-triazole, and 1,2,4-triazole. Polishing liquid composition for substrates.
<14>
The magnetic disk substrate according to any one of <1> to <13>, wherein the polishing liquid composition for a magnetic disk substrate further comprises a water-soluble polymer having no amino group and having an anionic group. Polishing liquid composition.
<15>
The water-soluble polymer having no amino group and having an anionic group is preferably an anion of at least one of a carboxylic acid group, a sulfonic acid group, a sulfate ester group, a phosphate ester group, and a phosphonic acid group. An anionic polymer having an ionic group, more preferably an anionic polymer having at least one of a sulfonic acid group and a carboxylic acid group, and still more preferably an anionic polymer having a sulfonic acid group. 14> The polishing liquid composition for magnetic disk substrates according to 14>.
<16>
A water-soluble polymer having no amino group and having an anionic group is a water-soluble polymer having a sulfonic acid group and an aromatic ring in each of the main chain and side chain thereof. The polishing composition for a magnetic disk substrate according to the above <14>, preferably a formaldehyde addition condensate of bis (4-hydroxyphenyl) sulfone and 4-hydroxybenzenesulfonic acid.
<17>
The molecular weight of the compound (A) is preferably 900 or less, more preferably 500 or less, preferably 30 or more, more preferably 50 or more, and further preferably 80 or more, according to any one of <1> to <16>. A polishing composition for a magnetic disk substrate.
<18>
The polishing composition for a magnetic disk substrate according to any one of <1> to <17>, wherein the compound (A) has an arylsulfonic acid group.
<19>
The polishing composition for a magnetic disk substrate according to any one of <1> to <18>, wherein the compound (A) includes an aminobenzenesulfonic acid skeleton.
<20>
The polishing composition for a magnetic disk substrate according to <19>, wherein the compound (A) is preferably at least one selected from the group consisting of sulfanilic acid, o-aminobenzenesulfonic acid, and metanilic acid.
<21>
The polishing composition for a magnetic disk substrate according to any one of <1> to <20> is supplied to a surface to be polished of a substrate to be polished, a polishing pad is brought into contact with the surface to be polished, and the polishing pad and A method of manufacturing a magnetic disk substrate, comprising: a step of moving the substrate to be polished and polishing the surface to be polished.
<22>
The method for producing a magnetic disk substrate according to <21>, wherein the substrate to be polished is a magnetic disk substrate having a Ni—P-containing layer.
<23>
In the step of polishing the surface to be polished, the supply amount of the polishing composition for the magnetic disk substrate is 0.05 to 15 mL / min per 1 cm ^{2 of the} substrate to be polished, according to <21> or <22> The manufacturing method of the magnetic disc board | substrate of description.
<24>
The method for manufacturing a magnetic disk substrate according to any one of <21> to <23>, wherein a polishing load is 5.0 to 20 kPa in the step of polishing the surface to be polished.
<25>
The polishing composition for a magnetic disk substrate according to any one of <1> to <20> is supplied to a surface to be polished of the substrate to be polished, a polishing pad is brought into contact with the surface to be polished, and the polishing pad And / or polishing the magnetic disk substrate, comprising moving the substrate to be polished to polish the surface to be polished.
<26>
The method for polishing a magnetic disk substrate according to <25>, wherein the substrate to be polished is a magnetic disk substrate having a Ni—P-containing layer.

[Examples 1 to 35 and Comparative Examples 1 to 8]
The polishing liquid compositions of Examples 1 to 35 and Comparative Examples 1 to 8 were prepared to polish the substrate to be polished, and washed with pure water to obtain an evaluation substrate. The polishing rate and the defect on the evaluation substrate surface were evaluated. Details of preparation method of polishing liquid composition, used compound (A), comparative compound of compound (A), and water-soluble polymer having an anionic group having no amino group, measuring method of each parameter, polishing condition ( The polishing method) and the evaluation method are as follows.

1. Preparation of polishing liquid composition Polishing material (colloidal silica), compound (A) or comparative compound shown in Table 1 and Table 2, acid, oxidizing agent (hydrogen peroxide, concentration: 35% by mass), necessary If necessary, a metal anticorrosive and a water-soluble polymer having an anionic group having no amino group are added to ion-exchanged water and stirred. If necessary, sulfuric acid and sodium hydroxide are further added to adjust the pH to 1. 5 of Examples 1 to 35 and Comparative Examples 1 to 8 were prepared. The contents of the abrasive and the oxidizing agent in the polishing composition were 5% by mass and 0.5% by mass, respectively. Further, the contents of the metal anticorrosive and the water-soluble polymer having an anionic group having no amino group, which were used as necessary, were 0.1% by mass and 0.01% by mass, respectively. The balance is water. The average particle size, ΔCV value, acid, content of acid in the polishing composition, content of compound (A) and comparative compound are shown in Tables 1 and 2 below. The breakdown of the content when two or more acids are used is as shown in Table 1.

[Compound (A)]
・ Sulfanilic acid (molecular weight: 128.17, manufactured by Wako Pure Chemical Industries, Ltd.)
O-Aminobenzenesulfonic acid (molecular weight: 173.19, manufactured by Wako Pure Chemical Industries, Ltd.)
・ Methanilic acid (molecular weight: 173.19, manufactured by Wako Pure Chemical Industries, Ltd.)
・ 3-Amino-4-hydroxybenzenesulfonic acid (molecular weight: 189.19, manufactured by Wako Pure Chemical Industries, Ltd.)
2-aminotoluene-5-sulfonic acid (molecular weight: 187.22, manufactured by Wako Pure Chemical Industries, Ltd.)
・ Sodium diphenylamine-4-sulfonate (molecular weight: 271.27, manufactured by Wako Pure Chemical Industries, Ltd.)
4-pyridineethanesulfonic acid (molecular weight: 188.23, manufactured by Wako Pure Chemical Industries, Ltd.)
・ Sodium cyclohexylaminoethanesulfonate (molecular weight: 207.29, manufactured by Nacalai Tesque)
・ N-tris (hydroxymethyl) methyl-2-aminoethanesulfonic acid (molecular weight: 229.25, manufactured by Merck & Co., Inc.)
・ Taurine (molecular weight: 125.15, manufactured by Wako Pure Chemical Industries, Ltd.)
[Comparative compound]
・ Aniline (Wako Pure Chemical Industries, Ltd.)
・ Benzenesulfonic acid (manufactured by Wako Pure Chemical Industries, Ltd.)
・ Sulphamic acid (Wako Pure Chemical Industries, Ltd.)
・ Sodium lauryl sulfate (trade name Emar 0, manufactured by Kao Corporation)
・ Ethanolamine (Wako Pure Chemical Industries, Ltd.)
・ Sodium propanesulfonate (manufactured by Wako Pure Chemical Industries, Ltd.)
・ Aminoarylsulfonic acid-phenol-formaldehyde condensate (weight average molecular weight = 12,500, product name: Floric SF200S, manufactured by Floric)

[Water-soluble polymer having an anionic group having no amino group]
The details of the water-soluble polymer having an anionic group having no amino group shown in Tables 1 and 2 are as follows.
・ Acrylic acid / acrylamido-2-methylpropanesulfonic acid copolymer sodium salt (hereinafter referred to as AA-AMPS, weight average molecular weight = 2,000 (catalog value), trade name: Aron A-6016A, manufactured by Toagosei Co., Ltd.)
Formaldehyde addition condensate of bis (4-hydroxyphenyl) sulfone and 4-hydroxybenzenesulfonic acid (hereinafter referred to as BisS / PhS, weight average molecular weight = 5,000 (catalog value), trade name WSR-SP28e, manufactured by Konishi Chemical Industries)

[Method for measuring weight average molecular weight of aminoarylsulfonic acid-phenol-formaldehyde condensate]
Column: TSKgel GMPWXL + TSKgel GMPWXL (Tosoh Corporation)
Eluent: 0.2M phosphate buffer / CH3CN = 7/3 (volume ratio)
Temperature: 40 ° C
Flow rate: 1.0 ml / min Sample size: 2 mg / ml
Detector: RI
Standard substance: Sodium polystyrene sulfonate (weight average molecular weight: 1,100, 3,610, 14,900, 152,000, manufactured by POLMER STANDARDS SERVICE)

[Measuring method of average particle diameter of abrasive and ΔCV value]
[Average particle size]
Colloidal silica, sulfuric acid, HEDP, and hydrogen peroxide used for the preparation of the polishing composition were added to ion-exchanged water and stirred to prepare a standard sample (pH 1.5). The contents of colloidal silica, sulfuric acid, HEDP, and hydrogen peroxide in the standard sample were 5% by mass, 0.5% by mass, 0.1% by mass, and 0.5% by mass, respectively. Scattering intensity distribution obtained by the Cumulant method at a detection angle of 90 ° when this standard sample is integrated 200 times with a dynamic light scattering device “DLS-6500” (manufactured by Otsuka Electronics Co., Ltd.) according to the instructions attached by the manufacturer. The particle size at which the area of the particles becomes 50% of the total was determined and used as the average particle size of colloidal silica.

[ΔCV value]
Using the same sample and measuring apparatus as described above, the CV value (CV30) of the colloidal silica particles at a detection angle of 30 ° was measured, and the value obtained by subtracting the CV value (CV90) of the colloidal silica particles at the detection angle of 90 ° was obtained. The ΔCV value was obtained.
(Measurement conditions for DLS-6500)
Detection angle: 90 °
Sampling time: 4 (μm)
Correlation Channel: 256 (ch)
Correlation Method: TI
Sampling temperature: 26.0 (℃)
Detection angle: 30 °
Sampling time: 10 (μm)
Correlation Channel: 1024 (ch)
Correlation Method: TI
Sampling temperature: 26.0 (℃)

2. Polishing Method Using the polishing liquid compositions of Examples 1 to 35 and Comparative Examples 1 to 8 prepared as described above, the following substrate to be polished was polished under the following polishing conditions, and the substrate after polishing was subjected to the following conditions: Washed with. Next, the defects on the polished substrate surface and the polishing rate were measured and evaluated under the following conditions.

[Polished substrate]
As the substrate to be polished, a substrate obtained by rough polishing an aluminum alloy substrate plated with Ni-P in advance with a polishing composition containing an alumina abrasive was used. The substrate to be polished has a thickness of 1.27 mm, an outer diameter of 95 mm, an inner diameter of 25 mm, a center line average roughness Ra measured by AFM (Digital Instrument NanoScope IIIa Multi Mode AFM), 1 nm, and long wavelength waviness (wavelength The amplitude of 0.4 to 2 mm was 2 nm, and the amplitude of short wavelength waviness (wavelength 50 to 400 μm) was 2 nm.

[Polishing conditions]
Polishing tester: "Fast double-sided 9B polishing machine" manufactured by Speedfam
Polishing pad: Fujibo's suede type (thickness 0.9mm, average hole diameter 30μm)
Polishing liquid composition supply amount: 100 mL / min (supply rate per 1 cm ^{2 of} substrate to be polished: 0.07
2mL / min)
Lower platen rotation speed: 32.5 rpm
Polishing load: 7.9 kPa
Polishing time: 5 minutes

[Cleaning conditions]
The substrate after polishing using the polishing composition of Examples 1 to 35 and Comparative Examples 1 to 8 was washed under the following conditions.
1) The substrate is immersed in ultrapure water and subjected to ultrasonic irradiation (950 kHz) for 1 minute.
2) The substrate after ultrasonic irradiation is transferred to a scrub cleaning unit on which a cleaning brush is set and cleaned.

[Defect measurement method]
Measuring instrument: OSA6100 (Candela Instruments)
Evaluation: Four substrates were randomly selected from the substrates put into the polishing tester, and after cleaning under the above cleaning conditions, each substrate was irradiated with a laser at 10,000 rpm to measure defects. The total number of defects (lines) on each of the four substrates was divided by 8 to calculate the number of defects per substrate surface. The results are shown in Table 1 and Table 2 below as relative values with Comparative Example 1 taken as 100.

[Measurement method of polishing rate]
The weight of each substrate before and after polishing is measured using a weigh scale “BP-210S” (manufactured by Sartorius), the change in the weight of each substrate is obtained, and the average value of 10 substrates is used as the weight reduction amount. The value divided by the polishing time was taken as the weight reduction rate. This weight reduction rate was introduced into the following formula and converted into a polishing rate (μm / min). The results are shown in Tables 1 and 2 below.
Polishing rate (μm / min) = weight reduction rate (g / min) / substrate single-sided area (mm ² ) / Ni-P plating density (g / cm ³ ) × 10 ⁶
(Substrate single-sided area: 6597 mm ² , Ni—P plating density: calculated as 7.9 g / cm ³ )

  As shown in Table 1 and Table 2 above, the polishing liquid compositions of Examples 1 to 35 ensure the polishing rate so as not to significantly impair the productivity as compared with the polishing liquid compositions of Comparative Examples 1 to 8. However, it has been shown that defects on the substrate surface after polishing are effectively reduced.

  According to the present invention, for example, a magnetic disk substrate suitable for increasing the recording density can be provided.

Claims (18)

  A magnetic material containing an abrasive, an acid, an oxidizing agent, and a compound (A) having a molecular weight of 1000 or less and having one or more amino groups and one or more sulfonic acid groups in one molecule, excluding abrasives, acids, oxidizing agents, and sulfamic acids. Polishing liquid composition for disk substrates.   The polishing composition for a magnetic disk substrate according to claim 1, wherein the substrate to be polished is a magnetic disk substrate having a Ni-P-containing layer.   The polishing composition for a magnetic disk substrate according to claim 1, wherein the pH is 0.5 or more and 4.0 or less.   4. The magnetic disk substrate polishing liquid according to claim 1, wherein the content of the compound (A) in the magnetic disk substrate polishing liquid composition is 0.3 mass% or less. 5. Composition.   5. The abrasive according to claim 1, wherein the abrasive is abrasive particles containing at least one material selected from the group consisting of silica, alumina, ceria, titania, zirconia, germania, silicon nitride, and silicon carbide. A polishing liquid composition for a magnetic disk substrate according to the item.   The polishing composition for a magnetic disk substrate according to any one of claims 1 to 5, wherein the abrasive is colloidal silica.   The polishing composition for a magnetic disk substrate according to any one of claims 1 to 6, further comprising a metal anticorrosive.   The polishing composition for a magnetic disk substrate according to claim 7, wherein the metal anticorrosive is an azole.   The magnetic disk substrate polishing according to claim 7 or 8, wherein the metal anticorrosive is at least one selected from the group consisting of benzotriazole, 1,2,3-triazole, and 1,2,4-triazole. Liquid composition.   The polishing composition for a magnetic disk substrate according to any one of claims 1 to 9, further comprising a water-soluble polymer having no amino group and having a sulfonic acid group.   The polishing composition for a magnetic disk substrate according to any one of claims 1 to 10, wherein the compound (A) has an aryl sulfonic acid group.   The polishing composition for a magnetic disk substrate according to any one of claims 1 to 11, wherein the compound (A) comprises an aminobenzenesulfonic acid skeleton.   A polishing composition for a magnetic disk substrate according to any one of claims 1 to 12 is supplied to a surface to be polished of a substrate to be polished, a polishing pad is brought into contact with the surface to be polished, and the polishing pad and / or Alternatively, a method for manufacturing a magnetic disk substrate, comprising the step of moving the substrate to be polished to polish the surface to be polished.   The method of manufacturing a magnetic disk substrate according to claim 13, wherein the substrate to be polished is a magnetic disk substrate having a Ni—P-containing layer. 15. The magnetic field according to claim 13, wherein in the step of polishing the surface to be polished, the supply amount of the polishing composition for the magnetic disk substrate is 0.05 to 15 mL / min per 1 cm < ² > of the substrate to be polished. A manufacturing method of a disk substrate.   The method for manufacturing a magnetic disk substrate according to claim 13, wherein a polishing load is 5.0 to 20 kPa in the step of polishing the surface to be polished.   A polishing liquid composition for a magnetic disk substrate according to any one of claims 1 to 12 is supplied to a surface to be polished of the substrate to be polished, a polishing pad is brought into contact with the surface to be polished, and the polishing pad and A method for polishing a magnetic disk substrate, comprising the step of moving the substrate to be polished and polishing the surface to be polished.   The method for polishing a magnetic disk substrate according to claim 17, wherein the substrate to be polished is a magnetic disk substrate having a Ni—P-containing layer.