JP2015081330A - Polishing liquid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing liquid composition which is a polishing liquid for substrates of magnetic disk drives and can reduce scratches, nano-defects and waviness of the surface of a substrate after polishing, and to provide a substrate production method and a substrate polishing method using the polishing liquid composition.SOLUTION: A polishing liquid composition comprises silica particles, and acid, a water-soluble polymer and water, and the water-soluble polymer contains structural units of formula (I) and structural units of formula (II) in the principal chain.

Description

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

  In recent years, magnetic disk drives have been reduced in size and capacity, and high recording density has been demanded. In order to increase the recording density, the unit recording area is reduced, and in order to improve the detection sensitivity of the weakened magnetic signal, 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 demand, a polishing liquid composition containing a copolymer having a functional group such as a carboxy group or a sulfonic acid group has been proposed (for example, Patent Documents 1 to 3).

  Patent Documents 1 and 2 provide a scratch by using an anionic surfactant having a repeating unit and a sulfonic acid (salt) group in the molecule and an aromatic group in the main chain of the repeating unit. Disclosed is an abrasive composition that can reduce defects such as the like, has less foaming in the polishing step, and can be efficiently polished.

  Patent Document 3 discloses a polishing liquid composition for a magnetic disk substrate that can reduce scratches and surface roughness of a polished substrate without impairing productivity by containing a water-soluble polymer having an anionic group.

JP 2010-135052 A JP 2012-135863 A JP 2010-170650 A

  With the increase in capacity of magnetic disk drives, the required characteristics for the surface quality of the substrate are becoming more severe, and scratches, nano defects (including protrusion defects and dent defects, the same applies hereinafter), and waviness on the substrate surface can be further reduced. There is a need for development of polishing liquid compositions.

  Therefore, the present disclosure provides a polishing composition that can reduce scratches, nano defects, and waviness on the surface of a substrate after polishing, and a method of manufacturing a magnetic disk substrate using the same.

[式（Ｉ）及び（II）中、Ｍは、それぞれ独立して、水素原子、アルカリ金属、アンモニウム又は有機アミンを表す。] In one aspect, the present disclosure is a polishing composition comprising silica particles, an acid, a water-soluble polymer, and water, wherein the water-soluble polymer is represented by the following formula (I) in the main chain. The present invention relates to a polishing liquid composition containing a structural unit represented by the following formula (II):

[In formula (I) and (II), M represents a hydrogen atom, an alkali metal, ammonium, or an organic amine each independently. ]

  In another aspect of the present disclosure, the polishing composition of the present disclosure is supplied to a surface to be polished of a substrate to be polished, the polishing pad is brought into contact with the surface to be polished, and at least one of the polishing pad and the substrate to be polished is The present invention relates to a method for manufacturing a substrate, including a step of moving and polishing.

  In another aspect of the present disclosure, the polishing composition of the present disclosure is supplied to a surface to be polished of a substrate to be polished, the polishing pad is brought into contact with the surface to be polished, and at least one of the polishing pad and the substrate to be polished is The present invention relates to a method for polishing a substrate, including moving and polishing.

  According to the polishing liquid composition of the present disclosure, in addition to scratching of the substrate surface after polishing, the substrate with reduced waviness of the substrate surface after polishing, preferably a magnetic disk substrate, more preferably, without impairing productivity. This can produce an effect that a perpendicular magnetic recording type magnetic disk substrate can be manufactured.

  In the present disclosure, the surface of a substrate after polishing is polished by polishing using a polishing composition containing a water-soluble copolymer having a constitutional unit having a structural unit having a phosphino group and a structural unit having a carboxy group in the main chain. Based on the knowledge that scratches, nano-defects and waviness can be reduced.

  That is, the present disclosure is a polishing composition containing silica particles, an acid, a water-soluble polymer, and water, wherein the water-soluble polymer is represented by the above formula (I) in the main chain. And a polishing liquid composition (hereinafter, also referred to as “polishing liquid composition of the present disclosure”) which is a water-soluble polymer containing a structural unit containing a structural unit containing the group represented by the above formula (II). .

  Although details of a mechanism that can reduce scratches, nano defects, and waviness on the substrate surface after polishing by the polishing liquid composition of the present disclosure are not clear, it is estimated as follows. That is, in the polishing liquid composition of the present disclosure, a carboxy group exhibiting hydrophobicity in a low pH region is adsorbed on a polishing pad to impart wettability, and a phosphino group interacts with a substrate to be polished to impart wettability. Conceivable. As a result, it is presumed that frictional vibration between the polishing pad and the substrate to be polished is suppressed, and scratches, nano defects and substrate surface waviness are reduced. However, the present disclosure may not be limited to this mechanism.

[Water-soluble polymer]
In the present disclosure, “water-soluble” means that, in one or more embodiments, the solubility in 100 g of water at 20 ° C. is 2 g or more. In addition, the “main chain” refers to the longest portion of the linear structure formed by combining monomer units in the water-soluble polymer, and the “side chain” is branched from the linear chain. The part that is.

The water-soluble polymer contains a structural unit represented by the following formula (I) and a structural unit containing a group represented by the following formula (II) in the main chain.

  In formulas (I) and (II), M is each independently a hydrogen atom, an alkali metal, ammonium or an organic amine. Examples of the alkali metal include sodium and potassium in one or more embodiments. In one or more embodiments, the organic amine includes ethylamine, methylamine, diethylamine, dimethylamine, triethylamine, trimethylamine, and alkanolamine. Among these, M in formula (I) is a hydrogen atom under acidic conditions (for example, pH 1.5) from the viewpoint of reducing scratches, nano-defects and waviness on the substrate surface after polishing in one or a plurality of embodiments. Is preferred. Further, in one or a plurality of embodiments, M in the formula (II) is preferably a hydrogen atom from the viewpoint of reducing scratches, nano defects and waviness on the polished substrate surface.

[式（III）中、Ｍ₁は、水素原子、アルカリ金属、アンモニウム又は有機アミンを表し、
Ｒ₁及びＲ₂は、それぞれ独立に、水素原子、メチル基、又はエチル基を表し、
Ｘ₁〜Ｘ₄は、それぞれ独立に、水素原子、脂肪族炭化水素基、アリール基、又は−Ｃ（＝Ｏ）Ｙ基を表し、Ｙは、−ＯＺ₁又は−ＮＺ₂Ｚ₃を表し、Ｚ₁は水素原子、アルカリ金属、又は脂肪族炭化水素基を表し、Ｚ₂及びＺ₃は、それぞれ独立に、水素原子、脂肪族炭化水素基、脂肪族スルホン酸、又は脂肪族スルホン酸塩を表し、かつ、Ｘ₁〜Ｘ₄のうち少なくとも１つは−ＣＯＯＭ₂であって、Ｍ₂は、水素原子、アルカリ金属、アンモニウム又は有機アミンを表し、
ｍ及びｎは、それぞれ独立に、１以上の数を表す] In one or a plurality of embodiments, the water-soluble polymer includes a structure represented by the following formula (III) from the viewpoint of reducing scratches, nano defects, and waviness on the substrate surface after polishing.

[In the formula (III), M ₁ represents a hydrogen atom, an alkali metal, ammonium or an organic amine,
R ₁ and R ₂ each independently represents a hydrogen atom, a methyl group, or an ethyl group,
X _{1 to} X ₄ each independently represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, or a —C (═O) Y group, Y represents —OZ ₁ or —NZ ₂ Z ₃ , Z ₁ represents a hydrogen atom, an alkali metal, or an aliphatic hydrocarbon group, and Z ₂ and Z ₃ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an aliphatic sulfonic acid, or an aliphatic sulfonate. And at least one of X _{1 to} X ₄ is —COOM ₂ , and M ₂ represents a hydrogen atom, an alkali metal, ammonium or an organic amine,
m and n each independently represents a number of 1 or more.

In the above formula (III), the structural units on both sides of the phosphino group (—P (O) (OM ₁ ) —) may be the same (R ₁ = R ₂ and X ₁ = X ₃ and X ₂ = X ₄ ) may be different. The alkali metal and organic amine in M ₁ and M ₂ of the above formula (III) can take one or more embodiments of M of the formula (I). In one or a plurality of embodiments, M _{1 in} formula (III) is a hydrogen atom under acidic conditions (for example, pH 1.5) from the viewpoint of reducing scratches, nano defects, and waviness on the substrate surface after polishing. From the same viewpoint, M ₂ in the formula (III) is preferably a hydrogen atom in one or more embodiments. In addition, R ₁ and R ₂ in the above formula (III) are preferably hydrogen atoms from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing. X ₁ and X ₃ in the above formula (III) are preferably hydrogen atoms from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing. X ₂ in the above formula (III) is preferably —COOH from the viewpoint of reducing scratches, nano defects and waviness on the polished substrate surface. It is a hydrogen atom. X ₄ in the above formula (III) is X ₂ or —C (O) —NH—C (CH ₃ ) (CH ₃ ) from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing. -CH ₂ -SO ₃ M is preferable. In one or more embodiments, the number of n and m in the above formula (III) is preferably m + n of 2 or more and 50 or less from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing. Preferably they are 3 or more and 20 or less.

In one or a plurality of embodiments, the water-soluble polymer includes hypophosphorous acid [HOP (O) H ₂ ] or a salt thereof, a monoethylenically unsaturated carboxylic acid or a salt thereof, and a monoethylenically unsaturated carboxylic acid. It is a copolymer obtained or obtained by polymerizing at least one monomer selected from the group consisting of derivatives or salts thereof.

  Monoethylenically unsaturated carboxylic acids include, in one or more embodiments, monoethylenically unsaturated monocarboxylic acids, monoethylenically unsaturated dicarboxylic acids, and combinations thereof. In one or a plurality of embodiments, examples of the monoethylenically unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, vinyl acetic acid, allyl acetic acid, propylidene acetic acid, ethylidene propionic acid, and dimethyl acrylic acid. In one or more embodiments, the monoethylenically unsaturated dicarboxylic acid is maleic acid, itaconic acid, mesaconic acid, fumaric acid, methylenemalonic acid, citraconic acid, anhydrides of these unsaturated dicarboxylic acids, such as maleic anhydride, etc. Further, a saponified product of the anhydride may be mentioned. Among these, the monoethylenically unsaturated carboxylic acid is preferably acrylic acid or methacrylic acid from the viewpoint of reducing scratches, nano defects, and waviness on the substrate surface after polishing in one or a plurality of embodiments. The monoethylenically unsaturated carboxylic acid can be used in the form of a salt as it is or after being neutralized.

  Monoethylenically unsaturated carboxylic acid derivatives include, in one or more embodiments, ester derivatives, amide derivatives, and combinations thereof. In one or more embodiments, the ester derivative of monoethylenically unsaturated carboxylic acid is hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene Glycol mono (meth) acrylate, glycerol mono (meth) acrylate, glycerol di (meth) acrylate, polytetramethylene glycol mono (meth) acrylate, polytetramethylene glycol di (meth) acrylate, butanediol mono (meth) acrylate, hexane (Meth) acrylates such as diol mono (meth) acrylate, pentaerythritol mono (meth) acrylate, and hydroxyphenoxyethyl (meth) acrylate Le acid esters. In one or a plurality of embodiments, the amide derivative of monoethylenically unsaturated carboxylic acid is (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, or Nn-propyl (meth) acrylamide. N-isopropyl (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-di-n-dipropyl (meth) acrylamide, N-methyl-N-ethyl (meth) acrylamide, 2 And (meth) acrylic acid amides such as -acrylamide-2-methylpropanesulfonic acid (AMPS). Among these, the monoethylenically unsaturated carboxylic acid derivative is 2-acrylamido-2-methyl from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing in one or a plurality of embodiments. Propanesulfonic acid (AMPS) is preferred.

  The content of the structural unit represented by the formula (I) in all the structural units constituting the water-soluble polymer is, in one or a plurality of embodiments, scratches, nano defects, and waviness on the substrate surface after polishing. From the viewpoint of reduction, it is preferably 1 mol% or more and 30 mol% or less, more preferably 5 mol% or more and 25 mol% or less, and still more preferably 5 mol% or more and 15 mol% or less.

  The content of the structural unit derived from diphosphorous acid or a salt thereof occupying in all the structural units constituting the water-soluble polymer is, in one or a plurality of embodiments, scratches on the substrate surface after polishing, nano defects, and From the viewpoint of reducing waviness, the content is preferably 1 mol% or more and 30 mol% or less, more preferably 5 mol% or more and 25 mol% or less, and further preferably 5 mol% or more and 15 mol% or less.

  In one or a plurality of embodiments, the content of the structural unit represented by the formula (II) in all the structural units constituting the water-soluble polymer may be scratches, nano defects and waviness on the substrate surface after polishing. From the viewpoint of reduction, it is preferably 70 mol% or more and 99 mol% or less, more preferably 25 mol% or more and 95 mol% or less, and still more preferably 85 mol% or more and 95 mol% or less.

  The content of the structural unit derived from the monoethylenically unsaturated carboxylic acid or a salt thereof in all the structural units constituting the water-soluble polymer is, in one or more embodiments, a scratch on the substrate surface after polishing, From the viewpoint of reducing nano defects and waviness, it is preferably 70 mol% or more and 99 mol% or less, more preferably 25 mol% or more and 95 or less, and further preferably 85 mol% or more and 95 mol% or less.

  In the present disclosure, as the content (mol%) of a certain structural unit in all the structural units constituting the water-soluble polymer, depending on the synthesis conditions, the reaction vessel may be used in all steps of the synthesis of the water-soluble polymer. The amount of the compound (mol%) for introducing the structural unit charged in the reaction vessel occupied in the compound for introducing all the structural units charged in may be used. In the present specification, the composition ratio (molar ratio) of two structural units constituting the water-soluble polymer may be charged into the reaction vessel in all steps of the synthesis of the water-soluble polymer depending on the synthesis conditions. Further, a compound amount ratio (molar ratio) for introducing the two structural units may be used.

[Other structural units]
The water-soluble polymer may have other structural units not included in the formula (III). The content of other structural units in all the structural units constituting the water-soluble polymer is 0 mol% or more and 30 mol% or less from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing. More preferably 0 mol% or more and 20 mol% or less, still more preferably 0 mol% or more and 10 mol% or less, still more preferably 0 mol% or more and 5 mol% or less, even more preferably substantially 0 mol% or 0 mol%.

  A structural unit derived from diphosphorous acid or a salt thereof (structural unit A) and a structural unit derived from a monoethylenically unsaturated carboxylic acid or a salt thereof (structural unit B) in all the structural units constituting the water-soluble polymer. ) Molar ratio (constituent unit A / constituent unit B) is preferably from 1/99 to 30/70, more preferably from the viewpoint of reducing scratches, nano defects and waviness on the substrate surface after polishing. It is 5/95 or more and 25/75 or less, more preferably 5/95 or more and 15/85 or less.

[Weight average molecular weight of water-soluble polymer]
The weight average molecular weight of the water-soluble polymer is preferably from 500 to 120,000, more preferably from 1,000 to 100,000, more preferably from the viewpoint of reducing scratches and waviness on the substrate surface after polishing without impairing productivity. 1000 or more and 50000 or less, still more preferably 1500 or more and 40000 or less, still more preferably 3000 or more and 40000 or less, still more preferably 4500 or more and 40000 or less, and even more preferably 5000 or more and 40000 or less. The weight average molecular weight is a value measured under the conditions described in Examples using gel permeation chromatography (GPC).

[Content of water-soluble polymer]
The content of the water-soluble polymer in the polishing composition of the present disclosure is 0.001% by mass or more and 1% by mass or less from the viewpoint of reducing scratches and waviness on the substrate surface after polishing without impairing productivity. More preferably, it is 0.003% by mass to 0.5% by mass, further preferably 0.005% by mass to 0.2% by mass, and still more preferably 0.007% by mass to 0.15% by mass. Even more preferably, 0.01% by weight to 0.1% by weight, even more preferably 0.01% by weight to 0.07% by weight, even more preferably 0.01% by weight to 0.05% by weight. It is as follows. In addition, in this specification, "content of the content component in polishing liquid composition" means content of the said component at the time of using polishing liquid composition for grinding | polishing. Therefore, when the polishing liquid composition of the present disclosure is prepared as a concentrate, the content of the components can be increased by the concentration.

[Abrasive]
The abrasive used in the polishing composition of the present disclosure includes silica, and colloidal silica is preferable from the viewpoint of reducing surface roughness and reducing scratches.

[Average particle size of abrasive]
The “average particle diameter of the abrasive” in the present disclosure refers to 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 distribution” unless otherwise specified). Also referred to as “average particle size based on”). The average particle size of the abrasive is preferably from 1 nm to 40 nm, more preferably from 5 nm to 37 nm, and even more preferably from 10 nm to 35 nm, from the viewpoint of reducing scratches on the substrate surface after polishing. The average particle size of the abrasive can be specifically obtained by the method described in the examples.

  The content of the abrasive in the polishing liquid composition of the present disclosure is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, from the viewpoint of improving the polishing rate. More preferably, it is 4 mass% or more. Further, from the viewpoint of reducing scratches on the substrate surface after polishing, it is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 13% by mass or less, and even more preferably 10% by mass or less. That is, the content of the abrasive is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, still more preferably 3% by mass or more and 13% by mass or less, and still more preferably. It is 4 mass% or more and 10 mass% or less.

[water]
Water in the polishing composition of the present disclosure is used as a medium, and examples thereof include distilled water, ion exchange water, and ultrapure water. From the viewpoint of the surface cleanliness of the substrate to be polished, ion exchange water and ultrapure water are preferable, and ultrapure water is more preferable. 60 mass% or more and 99.4 mass% or less are preferable, and, as for content of the water in polishing liquid composition, 70 mass% or more and 98.9 mass% or less are more preferable. Moreover, you may mix | blend organic solvents, such as alcohol, suitably in the range which does not inhibit the effect of this indication.

[acid]
The polishing composition of the present disclosure preferably contains an acid from the viewpoint of improving the polishing rate. In the present disclosure, the use of an acid includes the use of an acid and / or a salt thereof. Examples of the acid used in the polishing composition of the present disclosure include nitric acid, sulfuric acid, sulfurous acid, persulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, tripolyphosphoric acid, and amidosulfuric acid. Acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic 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-di Carboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, -Organic phosphonic acids such as phosphonobutane-2,3,4-tricarboxylic acid, α-methylphosphonosuccinic acid, aminocarboxylic acids such as glutamic acid, picolinic acid, aspartic acid, citric acid, tartaric acid, oxalic acid, nitroacetic acid, maleic Examples thereof include carboxylic acids such as acid and oxaloacetic acid. Among these, inorganic acids and organic phosphonic acids are preferable from the viewpoint of reducing scratches and undulations on the substrate surface, improving the stability of the oxidizing agent, and improving the waste liquid treatment property. Among inorganic acids, nitric acid, sulfuric acid, hydrochloric acid, perchloric acid, and phosphoric acid are preferable, and phosphoric acid and sulfuric acid are more preferable. Among organic phosphonic acids, hydroxyphosphonoacetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) and their salts 1-hydroxyethylidene-1,1-diphosphonic acid and aminotri (methylenephosphonic acid) are more preferable.

  The acids may be used alone or in admixture of two or more. However, 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 scratches, oxidizing agents. From the viewpoint of improving the stability of the liquid and improving the waste liquid treatment, it is further possible to use a mixture of two or more acids selected from the group consisting of phosphoric acid, sulfuric acid, and 1-hydroxyethylidene-1,1-diphosphonic acid preferable.

  The salt in the case of using the acid salt is not particularly limited, and specific examples thereof include 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, a salt with a metal belonging to Group 1A or ammonium is preferable from the viewpoint of reducing scratches on the substrate surface after polishing.

  The content of the acid and its salt in the polishing composition is preferably 0.001% by mass or more and 5.0% by mass or less, more preferably from the viewpoint of improving the polishing rate and reducing scratches on the substrate surface after polishing. Is 0.01% by mass or more and 4.0% by mass or less, more preferably 0.05% by mass or more and 3.0% by mass or less, still more preferably 0.1% by mass or more and 2.0% by mass or less, More preferably, it is 0.4 mass% or more and 1.0 mass% or less.

[Oxidant]
The polishing composition of the present disclosure preferably contains an oxidant from the viewpoints of improving the polishing rate, scratching the substrate surface, and reducing waviness. Examples of the oxidizing agent that can be used in the polishing liquid composition of the present disclosure 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, metal salt, nitric acid, Examples include sulfuric acid.

  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. Peroxoacids or salts thereof include peroxodisulfuric acid, ammonium peroxodisulfate, metal peroxodisulfate, 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 scratches on the substrate surface after polishing and substrate surface waviness include hydrogen peroxide, iron (III) nitrate, peracetic acid, ammonium peroxodisulfate, iron (III) sulfate, and iron iron (III) ammonium sulfate. Etc. 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, and further preferably 0.1% by mass or more from the viewpoint of improving the polishing rate. Yes, from the viewpoint of reducing scratches on the substrate surface after polishing and substrate surface waviness, it is preferably 4% by mass or less, more preferably 2% by mass or less, and further preferably 1% by mass or less. Therefore, in order to improve the polishing rate while maintaining the surface quality, the content is preferably 0.01% by mass to 4% by mass, more preferably 0.05% by mass to 2% by mass, and still more preferably. Is 0.1 mass% or more and 1 mass% or less.

[Other ingredients]
The polishing liquid composition of the present disclosure may contain other components as necessary. Examples of other components include a thickener, a dispersant, a rust inhibitor, a basic substance, and a surfactant. The content of these other optional components in the polishing liquid composition is preferably 0% by mass or more and 10% by mass or less, and more preferably 0% by mass or more and 5% by mass or less. However, the polishing liquid composition of the present disclosure can exhibit the effect of reducing scratches and undulations on the substrate surface without containing other components, particularly a surfactant. Furthermore, the polishing composition of the present disclosure can contain alumina abrasive grains and can be used in a rough polishing step prior to the final polishing step.

[PH of polishing composition]
The pH of the polishing composition of the present disclosure is preferably 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, from the viewpoint of improving the polishing rate. is there. Moreover, 0.5 or more is preferable from a viewpoint of surface roughness reduction, More preferably, it is 0.8 or more, More preferably, it is 1.0 or more, More preferably, it is 1.2 or more. Therefore, the pH of the polishing composition is preferably 0.5 or more and 4.0 or less, more preferably 0.8 or more and 3.5 or less, still more preferably 1.0 or more and 3.0 or less, and even more preferably 1. .2 or more and 2.5 or less.

[Method for preparing polishing liquid composition]
The polishing composition of the present disclosure is prepared by, for example, mixing water, an abrasive, a water-soluble polymer, and, if desired, an acid and / or a salt thereof, an oxidizing agent, and other components by a known method. Can be prepared. At this time, the abrasive may be mixed in a concentrated slurry state or may be mixed after being diluted with water or the like. The content and concentration of each component in the polishing liquid composition of the present disclosure are in the above-described range, but as another embodiment, the polishing liquid composition of the present disclosure may be prepared as a concentrate.

  The polishing liquid composition of this indication can be used conveniently for manufacture of the board | substrate for precision components. For example, it is suitable for the polishing of magnetic disk substrates such as magnetic disks, magneto-optical disks, optical disks, etc., photomask substrates, optical lenses, optical mirrors, optical prisms, semiconductor substrates, and other precision component substrates. Suitable for In the manufacture of a semiconductor substrate, the polishing liquid of the present disclosure is used in a polishing process of a silicon wafer (bare wafer), a process of forming an embedded element isolation film, a process of planarizing an interlayer insulating film, a process of forming embedded metal wiring, a process of forming embedded capacitors Compositions can be used.

  The material of the object to be polished for which the polishing composition of the present disclosure is suitable includes, for example, metals or semimetals such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, or alloys thereof, glass, glassy carbon, Examples thereof include glassy substances such as amorphous carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium carbide, and resins such as polyimide resin. Among these, it is suitable for an object to be polished containing a metal such as aluminum, nickel, tungsten, or copper and an alloy mainly composed of these metals. For example, a Ni—P plated aluminum alloy substrate or a glass substrate such as crystallized glass or tempered glass is more suitable, and a Ni—P plated aluminum alloy substrate is more suitable.

[Substrate manufacturing method]
As another aspect, the present disclosure relates to a substrate manufacturing method (hereinafter, also referred to as “the manufacturing method of the present disclosure”). The production method of the present disclosure includes a step of polishing the substrate to be polished while bringing the polishing composition described above into contact with the polishing pad (hereinafter, also referred to as “polishing step using the polishing composition of the present disclosure”). A method for manufacturing a substrate. Thereby, in addition to scratches on the substrate surface after polishing, it is possible to provide a substrate in which waviness on the substrate surface after polishing is reduced. The manufacturing method of the present disclosure 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. Therefore, as another aspect, the manufacturing method of the present disclosure is a method of manufacturing a substrate including a polishing step using the polishing liquid composition of the present disclosure, preferably a method of manufacturing a magnetic disk substrate, and more preferably vertical. This is a method of manufacturing a magnetic disk substrate for a magnetic recording system.

  In one or a plurality of embodiments, the polishing process using the polishing liquid composition of the present disclosure supplies the polishing liquid composition of the present disclosure to the surface to be polished of the substrate to be polished, and contacts the polishing pad with the surface to be polished. And polishing at least one of the polishing pad and the substrate to be polished, or sandwiching the substrate to be polished with a surface plate to which a polishing pad such as a non-woven organic polymer polishing cloth is attached, This is a step 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 present disclosure to the polishing machine.

  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 disclosure is preferably performed in the second and subsequent stages, 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. In addition, the polishing composition of the present disclosure can also be used in cyclic polishing in which the used polishing liquid is reused. 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 disclosure is not particularly limited, and a suede type, a nonwoven fabric type, a polyurethane closed-cell foam type, or a two-layer type laminated with these can be used. From the viewpoint, a suede type polishing pad is preferable.

  The average hole 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 even more preferably 35 μm or less, from the viewpoint of scratch reduction and pad life. 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 opening 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, further 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 composition of the present disclosure is preferably 5.9 kPa or more, more preferably 6.9 kPa or more, and further preferably 7.5 kPa or more. Thereby, since the fall of a grinding | polishing speed | rate can be suppressed, productivity can be improved. In the manufacturing method of the present disclosure, 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 composition of the present disclosure, the polishing load is preferably 20 kPa or less, more preferably 18 kPa or less, and still more preferably 16 kPa or less. Thereby, generation | occurrence | production of a scratch can be suppressed. Accordingly, in the polishing step using the polishing composition of the present disclosure, the polishing pressure is preferably 5.9 kPa to 20 kPa, more preferably 6.9 kPa to 18 kPa, and even more preferably 7.5 kPa to 16 kPa. 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 disclosure in the polishing step using the polishing composition of the present disclosure is preferably 0.05 mL / min or more and 15 mL / min or less per 1 cm ^{2 of the} substrate to be polished from the viewpoint of reducing scratches. More preferably 0.06 mL / min to 10 mL / min, still more preferably 0.07 mL / min to 1 mL / min, and even more preferably 0.07 mL / min to 0.5 mL / min.

  As a method of supplying the polishing composition of the present disclosure 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 disclosure.

[Polished substrate]
Examples of the material of the substrate to be polished preferably used in the present disclosure include metals, metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, or alloys thereof, glass, glassy carbon, and amorphous. Examples thereof include glassy substances such as carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium carbide, and resins such as polyimide resin. Among them, a polished substrate or a glass substrate containing a metal such as aluminum, nickel, tungsten, or copper, or an alloy containing these metals as a main component is preferable. Among these, an aluminum alloy substrate plated with Ni—P or an aluminosilicate glass substrate is suitable, and an aluminum alloy substrate plated with Ni—P is more suitable. 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.

  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, for example, about 2 to 95 mm, and the thickness is, for example, about 0.5 to 2 mm.

  Further, according to the present disclosure, in addition to scratching of the substrate surface after polishing, a substrate with reduced waviness of the substrate surface after polishing can be provided, so that a magnetic disk substrate that requires high surface smoothness, especially It can be suitably used for polishing a perpendicular magnetic recording type magnetic disk substrate.

[Polishing method]
As another aspect, the present disclosure relates to a polishing method for a substrate to be polished, which includes polishing the substrate to be polished using the polishing composition of the present disclosure. By using the polishing method of the present disclosure, in addition to scratching of the substrate surface after polishing, a substrate with reduced waviness of the substrate surface after polishing is provided. Examples of the substrate to be polished in the polishing method of the present disclosure include those used for manufacturing a magnetic disk substrate as described above, and among them, a substrate used for manufacturing a magnetic disk substrate for a perpendicular magnetic recording system is preferable. The specific polishing method and conditions can be as described above.

  Polishing the substrate to be polished using the polishing liquid composition of the present disclosure includes supplying the polishing liquid composition of the present disclosure to the surface to be polished of the substrate to be polished in one or a plurality of embodiments. A polishing pad is brought into contact, and at least one of the polishing pad and the substrate to be polished is moved for polishing, or a surface plate to which a polishing pad such as a non-woven organic polymer polishing cloth is attached is coated. It is to polish the substrate to be polished by moving the surface plate or the substrate to be polished while sandwiching the polishing substrate and supplying the polishing composition of the present disclosure to the polishing machine.

  Regarding the above-described embodiment, the present disclosure further discloses a composition, a production method, or an application according to one or more of the following embodiments.

[式（Ｉ）及び（II）中、Ｍは、それぞれ独立して、水素原子、アルカリ金属、アンモニウム又は有機アミンを表す。] <1> A polishing composition comprising silica particles, an acid, a water-soluble polymer, and water, wherein the water-soluble polymer is represented by the following formula (I) in the main chain. A polishing liquid composition comprising a unit and a structural unit containing a group represented by the following formula (II).

[In formula (I) and (II), M represents a hydrogen atom, an alkali metal, ammonium, or an organic amine each independently. ]

[式（III）中、Ｍ₁は、水素原子、アルカリ金属、アンモニウム又は有機アミンを表し、
Ｒ₁及びＲ₂は、それぞれ独立に、水素原子、メチル基、又はエチル基を表し、
Ｘ₁〜Ｘ₄は、それぞれ独立に、水素原子、脂肪族炭化水素基、アリール基、又は−Ｃ（＝Ｏ）Ｙ基を表し、Ｙは、−ＯＺ₁又は−ＮＺ₂Ｚ₃を表し、Ｚ₁は水素原子、アルカリ金属、脂肪族炭化水素基を表し、Ｚ₂、及びＺ₃は、それぞれ独立に、水素原子、脂肪族炭化水素基、脂肪族スルホン酸、又は脂肪族スルホン酸塩を表し、かつ、Ｘ₁〜Ｘ₄のうち少なくとも１つは−ＣＯＯＭ₂であって、Ｍ₂は、水素原子、アルカリ金属、アンモニウム又は有機アミンを表し、
ｍ及びｎは、それぞれ独立に、１以上の数を表す]
＜３＞ 式（III）におけるＲ₁及びＲ₂が、好ましくは水素原子である、＜２＞記載の研磨液組成物。
＜４＞ 式（III）におけるＭ₁が。好ましくは、酸性条件下（例えばｐＨ１．５）において水素原子となるもの、より好ましくはナトリウム又は水素原子、さらに好ましくは水素原子である、＜２＞又は＜３＞に記載の研磨液組成物。
＜５＞ 式（III）におけるＭ₂が、好ましくは水素原子である、＜２＞から＜４＞のいずれかに記載の研磨液組成物。
＜６＞ 式（III）におけるＸ₁及びＸ₃が、好ましくは水素原子である、＜２＞から＜５＞のいずれかに記載の研磨液組成物。
＜７＞ 式（III）におけるＸ₂が、好ましくは−ＣＯＯＨである、＜２＞から＜６＞のいずれかに記載の研磨液組成物。
＜８＞ 式（III）におけるＸ₄が、好ましくはＸ₂、又は、-C(O)-NH-C(CH₃)(CH₃)-CH₂-SO₃Mであって、Ｍは、好ましくは、酸性条件下（例えばｐＨ１．５）において水素原子となるもの、より好ましくはナトリウム又は水素原子である、＜２＞から＜７＞のいずれかに記載の研磨液組成物。
＜９＞ 式（III）におけるｎ及びｍの数は、ｍ＋ｎが、好ましくは２以上、より好ましくは３以上となる数である、＜２＞から＜８＞のいずれかに記載の研磨液組成物。
＜１０＞ 式（III）におけるｎ及びｍの数は、ｍ＋ｎが、好ましくは５０以下、より好ましくは２０以下となる数である、＜２＞から＜９＞のいずれかに記載の研磨液組成物。
＜１１＞ 前記水溶性重合体を構成する全構成単位中に占める式（Ｉ）で表される構成単位の含有量が、好ましくは１モル％以上、より好ましくは５モル％以上である、＜１＞から＜１０＞のいずれかに記載の研磨液組成物。
＜１２＞ 前記水溶性重合体を構成する全構成単位中に占める式（Ｉ）で表される構成単位の含有量はが、好ましくは３０モル％以下、より好ましくは２５モル％以下、さらに好ましくは１５モル％以下である、＜１＞から＜１１＞のいずれかに記載の研磨液組成物。
＜１３＞ 前記水溶性重合体を構成する全構成単位中に占める式（Ｉ）で表される構成単位の含有量が、好ましくは１モル％以上３０モル％以下、より好ましくは５モル％以上２５モル％以下、さらに好ましくは５モル％以上１５モル％以下である、＜１＞から＜１２＞のいずれかに記載の研磨液組成物。
＜１４＞ 前記水溶性重合体を構成する全構成単位中に占める式（II）で表される構成単位の含有量が、好ましくは７０モル％以上、より好ましくは２５モル％以上、さらに好ましくは８５モル％以上である、＜１＞から＜１３＞のいずれかに記載の研磨液組成物。
＜１５＞ 前記水溶性重合体を構成する全構成単位中に占める式（II）で表される構成単位の含有量が、好ましくは９９モル％以下、より好ましくは９５以下である、＜１＞から＜１４＞のいずれかに記載の研磨液組成物。
＜１６＞ 前記水溶性重合体が、次亜リン酸又はその塩と、モノエチレン性不飽和カルボン酸又はその塩及びモノエチレン性不飽和カルボン酸誘導体又はその塩からなる群から選ばれるすくなくとも１種のモノマーとを重合させて得られる共重合体である、＜１＞から＜１５＞のいずれかに記載の研磨液組成物。
＜１７＞ 前記水溶性重合体を構成する全構成単位中におけるジ亜リン酸又はその塩に由来する構成単位（構成単位Ａ）とモノエチレン性不飽和カルボン酸又はその塩に由来する構成単位（構成単位Ｂ）のモル比率（構成単位Ａ／構成単位Ｂ）が、好ましくは１／９９以上、より好ましくは５／９５以上、さらに好ましくは５／９５以上である、＜１＞から＜１６＞のいずれかに記載の研磨液組成物。
＜１８＞ 前記水溶性重合体を構成する全構成単位中におけるジ亜リン酸又はその塩に由来する構成単位（構成単位Ａ）とモノエチレン性不飽和カルボン酸又はその塩に由来する構成単位（構成単位Ｂ）のモル比率（構成単位Ａ／構成単位Ｂ）が、好ましくは３０／７０以下、より好ましくは２５／７５以下、さらに好ましくは１５/８５以下である、＜１＞から＜１７＞のいずれかに記載の研磨液組成物。
＜１９＞ 前記水溶性重合体が、ビス（ポリ−２−カルボキシエチル）ホスフィン酸、ホスフィノカルボン酸共重合体、これらの塩、及びこれらの組み合わせからなる群から選ばれる、＜１＞から＜１８＞のいずれかに記載の研磨液組成物。
＜２０＞ 前記水溶性重合体の重量平均分子量が、好ましくは５００以上、より好ましくは１０００以上、さらに好ましくは１５００以上、さらにより好ましくは３０００以上、さらにより好ましくは４５００以上、さらにより好ましくは５０００以上である、＜１＞から＜１９＞のいずれかに記載の研磨液組成物。
＜２１＞ 前記水溶性重合体の重量平均分子量が、好ましくは１２００００以下、より好ましくは１０００００以下、さらに好ましくは５００００以下、さらにより好ましくは４００００以下である、＜１＞から＜２０＞のいずれかに記載の研磨液組成物。
＜２２＞ 前記シリカ粒子の平均粒径が、好ましくは１ｎｍ以上４０ｎｍ以下、より好ましくは５ｎｍ以上３７ｎｍ以下、さらに好ましくは１０ｎｍ以上３５ｎｍ以下である、＜１＞から＜２１＞のいずれかに記載の研磨液組成物。
＜２３＞ 被研磨基板がＮｉ―Ｐ含有層を有する磁気ディスク基板である、＜１＞から＜２２＞のいずれかに記載の研磨液組成物。
＜２４＞ 研磨液組成物のｐＨが、好ましくは０．５以上４．０以下、より好ましくは０．８以上３．５以下、さらに好ましくは１．０以上３．０以下、さらにより好ましくは１．２以上２．５以下である、＜１＞から＜２３＞のいずれかに記載の研磨液組成物。
＜２５＞ ＜１＞から＜２４＞のいずれかに記載の研磨液組成物を被研磨基板の研磨対象面に供給し、前記研磨対象面に研磨パッドを接触させ、前記研磨パッド及び前記被研磨基板の少なくとも一方を動かして研磨する工程を含む、基板の製造方法。
＜２６＞ ＜１＞から＜２４＞のいずれかに記載の研磨液組成物を被研磨基板の研磨対象面に供給し、前記研磨対象面に研磨パッドを接触させ、前記研磨パッド及び前記被研磨基板の少なくとも一方を動かして研磨することを含む、基板の研磨方法。 <2> The polishing composition according to <1>, wherein the water-soluble polymer includes a structure represented by the following formula (III).

[In the formula (III), M ₁ represents a hydrogen atom, an alkali metal, ammonium or an organic amine,
R ₁ and R ₂ each independently represents a hydrogen atom, a methyl group, or an ethyl group,
X _{1 to} X ₄ each independently represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, or a —C (═O) Y group, Y represents —OZ ₁ or —NZ ₂ Z ₃ , Z ₁ represents a hydrogen atom, an alkali metal, or an aliphatic hydrocarbon group, and Z ₂ and Z ₃ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an aliphatic sulfonic acid, or an aliphatic sulfonate. And at least one of X _{1 to} X ₄ is —COOM ₂ , and M ₂ represents a hydrogen atom, an alkali metal, ammonium or an organic amine,
m and n each independently represents a number of 1 or more.
<3> The polishing composition according to <2>, wherein R ₁ and R ₂ in formula (III) are preferably hydrogen atoms.
<4> M ₁ in the formula (III). Preferably, the polishing composition according to <2> or <3>, which is a hydrogen atom under acidic conditions (for example, pH 1.5), more preferably a sodium or hydrogen atom, and still more preferably a hydrogen atom.
<5> The polishing composition according to any one of <2> to <4>, wherein M ₂ in formula (III) is preferably a hydrogen atom.
<6> The polishing composition according to any one of <2> to <5>, wherein X ₁ and X ₃ in formula (III) are preferably hydrogen atoms.
<7> The polishing composition according to any one of <2> to <6>, wherein X ₂ in formula (III) is preferably —COOH.
<8> X ₄ in formula (III) is preferably X ₂ or —C (O) —NH—C (CH ₃ ) (CH ₃ ) —CH ₂ —SO ₃ M, wherein M is The polishing composition according to any one of <2> to <7>, which is preferably a hydrogen atom under acidic conditions (for example, pH 1.5), more preferably sodium or a hydrogen atom.
<9> The polishing composition according to any one of <2> to <8>, wherein the number of n and m in formula (III) is a number such that m + n is preferably 2 or more, more preferably 3 or more. object.
<10> The polishing composition according to any one of <2> to <9>, wherein the numbers n and m in formula (III) are such that m + n is preferably 50 or less, more preferably 20 or less. object.
<11> The content of the structural unit represented by the formula (I) in all the structural units constituting the water-soluble polymer is preferably 1 mol% or more, more preferably 5 mol% or more. Polishing liquid composition in any one of <1> to <10>.
<12> The content of the structural unit represented by the formula (I) in all the structural units constituting the water-soluble polymer is preferably 30 mol% or less, more preferably 25 mol% or less, and still more preferably. Is a polishing composition according to any one of <1> to <11>, which is 15 mol% or less.
<13> The content of the structural unit represented by the formula (I) in all the structural units constituting the water-soluble polymer is preferably 1 mol% or more and 30 mol% or less, more preferably 5 mol% or more. The polishing composition according to any one of <1> to <12>, which is 25 mol% or less, more preferably 5 mol% or more and 15 mol% or less.
<14> The content of the structural unit represented by the formula (II) in all the structural units constituting the water-soluble polymer is preferably 70 mol% or more, more preferably 25 mol% or more, and still more preferably. Polishing liquid composition in any one of <1> to <13> which is 85 mol% or more.
<15> The content of the structural unit represented by the formula (II) in all the structural units constituting the water-soluble polymer is preferably 99 mol% or less, more preferably 95 or less, <1> To <14>.
<16> The water-soluble polymer is at least one selected from the group consisting of hypophosphorous acid or a salt thereof, a monoethylenically unsaturated carboxylic acid or a salt thereof, and a monoethylenically unsaturated carboxylic acid derivative or a salt thereof. The polishing composition according to any one of <1> to <15>, which is a copolymer obtained by polymerizing the monomer.
<17> A structural unit derived from diphosphorous acid or a salt thereof in all the structural units constituting the water-soluble polymer (structural unit A) and a structural unit derived from a monoethylenically unsaturated carboxylic acid or a salt thereof ( <1> to <16> The molar ratio of the structural unit B) (structural unit A / structural unit B) is preferably 1/99 or more, more preferably 5/95 or more, and even more preferably 5/95 or more. A polishing composition according to any one of the above.
<18> A structural unit derived from diphosphorous acid or a salt thereof in all the structural units constituting the water-soluble polymer (structural unit A) and a structural unit derived from a monoethylenically unsaturated carboxylic acid or a salt thereof ( <1> to <17> The molar ratio of the structural unit B) (structural unit A / structural unit B) is preferably 30/70 or less, more preferably 25/75 or less, and even more preferably 15/85 or less. A polishing composition according to any one of the above.
<19> The water-soluble polymer is selected from the group consisting of bis (poly-2-carboxyethyl) phosphinic acid, phosphinocarboxylic acid copolymers, salts thereof, and combinations thereof, from <1> to <1>18> The polishing liquid composition according to any one of the above.
<20> The weight average molecular weight of the water-soluble polymer is preferably 500 or more, more preferably 1000 or more, still more preferably 1500 or more, still more preferably 3000 or more, still more preferably 4500 or more, and even more preferably 5000. The polishing liquid composition according to any one of <1> to <19>.
<21> The water-soluble polymer has a weight average molecular weight of preferably 120,000 or less, more preferably 100,000 or less, still more preferably 50000 or less, and even more preferably 40000 or less, any one of <1> to <20> The polishing liquid composition as described in 2. above.
<22> The average particle diameter of the silica particles is preferably 1 nm to 40 nm, more preferably 5 nm to 37 nm, and still more preferably 10 nm to 35 nm, according to any one of <1> to <21>. Polishing liquid composition.
<23> The polishing composition according to any one of <1> to <22>, wherein the substrate to be polished is a magnetic disk substrate having a Ni—P-containing layer.
<24> The pH of the polishing composition is preferably 0.5 or more and 4.0 or less, more preferably 0.8 or more and 3.5 or less, still more preferably 1.0 or more and 3.0 or less, and still more preferably. The polishing composition according to any one of <1> to <23>, which is 1.2 or more and 2.5 or less.
<25> The polishing composition according to any one of <1> to <24> 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 the object to be polished A method for manufacturing a substrate, comprising the step of polishing by moving at least one of the substrates.
<26> The polishing composition according to any one of <1> to <24> 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 the object to be polished A method for polishing a substrate, comprising polishing by moving at least one of the substrates.

[Examples 1-8 and Comparative Examples 1-4]
The polishing liquid compositions of Examples 1 to 8 and Comparative Examples 1 to 4 were prepared to polish the substrate to be polished, washed with pure water to obtain an evaluation substrate, and the surface of the evaluation substrate was swelled, nano defects The number and the number of scratches were evaluated. The water-soluble polymer used, the method for preparing the polishing composition, the method for measuring each parameter, the polishing conditions (polishing method), and the evaluation method are as follows.

1. Preparation of Polishing Liquid Composition Abrasive material (colloidal silica), a water-soluble polymer, an acid, and hydrogen peroxide solution (concentration: 35% by mass) were added to ion-exchanged water and stirred to obtain Example 1. -8 and Comparative Examples 1-4 were prepared (pH 1.5).
As the colloidal silica, spherical silica having an average particle diameter of 25 nm was used in an addition amount of 6.0% by mass.
The acid is sulfuric acid, HEDP (1-hydroxyethylidene-1,1-diphosphonic acid, manufactured by Sorcia Japan), or phosphoric acid, respectively, at 0.4 mass%, 1.0 mass%, or 1.0 mass%. Used in addition amount (Table 2).
Hydrogen peroxide was used in an addition amount of 0.4% by mass.
The water-soluble polymer has the composition of the water-soluble polymers A, B, and C shown in Table 1, and the amount of the weight average molecular weight shown in Table 2 is 0.02% by mass or 0.05% by mass. Used in. The weight average molecular weight was measured by the gel permeation chromatography (GPC) method under the following conditions.
In Comparative Examples 3 and 4, phosphinic acid (H ₂ P (O) OH) was used in an addition amount of 0.05% by mass.

[Method for measuring weight average molecular weight of water-soluble copolymer A]
Column: TSKgel α-M + TSKgel α-M (manufactured by Tosoh Corporation)
Eluent: 60 mmol / L phosphoric acid, 50 mmol / L LiBr / DMF
Temperature: 40 ° C
Flow rate: 1.0 ml / min Sample size: 5 mg / ml
Detector: RI
Standard substance: Polystyrene (Molecular weight 3600, 30000: manufactured by Nishio Kogyo Co., Ltd.

[Method for measuring weight average molecular weight of water-soluble copolymers B and C]
Column: G4000PWXL + G2500PWXL (manufactured by Tosoh)
Eluent: 0.2 M phosphate buffer / CH ₃ CN = 9/1 Volume ratio Temperature: 40 ° C.
Flow rate: 1.0 ml / min Sample size: 5 mg / ml
Detector: RI
Standard substance: Polyethylene glycol (24,000, 101,000, 185,000, 540,000: manufactured by Tosoh Corporation, 2580, 875,000, manufactured by Sowa Kagaku)

[Average particle size of colloidal silica]
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. The area of the 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. Was determined as the average particle size of colloidal silica.

2. Polishing method The following to-be-polished substrate was grind | polished on the grinding | polishing conditions shown below using the polishing liquid composition of Examples 1-8 and Comparative Examples 1-4 which were prepared as mentioned above. Next, the waviness, the number of nano defects, and the number of scratches on the polished substrate surface were measured. The results are shown in Table 2.

[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, and an inner diameter of 25 mm. The center line average roughness Ra measured by AFM (Digital Instrument NanoScope IIIa Multi Mode AFM) is 1 nm, and a long wavelength waviness ( The amplitude of the wavelength 0.4-2 mm was 2 nm, and the amplitude of the short wavelength waviness (wavelength 50-400 μm) was 2 nm.

[Polishing conditions]
Polishing tester: "Fast double-sided 9B polishing machine" manufactured by Speedfam
Polishing pad: Fujibow Suede type (thickness 0.9mm, average hole diameter 15μm)
Polishing liquid composition supply amount: 100 mL / min (supply rate per 1 cm ^{2 of} substrate to be polished: 0.15 mL / min)
Lower platen rotation speed: 32.5 rpm
Polishing load: 10 kPa
Polishing time: 6 minutes

[Evaluation method of swell (short wavelength swell)]
Three substrates were arbitrarily selected from the eight substrates after polishing and measured under the following conditions. The average value of the three measured values was calculated as the short wavelength waviness of the substrate. The results are shown in Table 2 below as relative values with Comparative Example 1 taken as 100.
Measuring machine: New View 5032 (manufactured by Zygo)
Lens: 2.5 times Zoom: 0.5 times Measurement wavelength: 80-500 μm (short wavelength swell)
Measurement position: Radius 27mm from the center of the board
Analysis software: Zygo Metro Pro (manufactured by Zygo)

[Measurement method of the number of nano defects]
Measuring instrument: OSA7100 (manufactured by KLA Tencor)
Evaluation: Four substrates were randomly selected from the substrates put into the polishing tester, and each substrate was irradiated with a laser at 8000 rpm to measure the number of nano defects. The total number of nano-defects (pieces) on both sides of each of the four substrates was divided by 8 to calculate the number of nano-defects (pieces) per substrate surface. The results are shown in Table 2 below as relative values with Comparative Example 1 taken as 100.

[Measurement method of the number of scratches]
Measuring instrument: OSA7100 (manufactured by KLA Tencor)
Evaluation: Four substrates were randomly selected from the substrates put into the polishing tester, and each substrate was irradiated with a laser at 10,000 rpm to measure scratches. The total number of scratches (both) on each of the four substrates was divided by 8 to calculate the number of scratches per substrate surface. The results are shown in Table 2 below as relative values with Comparative Example 1 taken as 100.

  As shown in Table 2 above, the polishing liquid compositions of Examples 1 to 8 have short wavelength waviness, nano defects on the substrate surface, and scratches on the substrate surface as compared with the polishing liquid compositions of Comparative Examples 1 to 4. It has been shown to reduce effectively.

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

Claims (9)

A polishing composition comprising silica particles, an acid, a water-soluble polymer, and water,
Polishing liquid composition in which the said water-soluble polymer contains the structural unit represented by the structural unit represented by following formula (I) in the principal chain, and the following formula (II).

[In formula (I) and (II), M represents a hydrogen atom, an alkali metal, ammonium, or an organic amine each independently. ] The polishing liquid composition according to claim 1, wherein the water-soluble polymer includes a structure represented by the following formula (III).

[In the formula (III), M ₁ represents a hydrogen atom, an alkali metal, ammonium or an organic amine,
R ₁ and R ₂ each independently represents a hydrogen atom, a methyl group, or an ethyl group,
X _{1 to} X ₄ each independently represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, or a —C (═O) Y group, Y represents —OZ ₁ or —NZ ₂ Z ₃ , Z ₁ represents a hydrogen atom, an alkali metal, or an aliphatic hydrocarbon group, and Z ₂ and Z ₃ each independently represent a hydrogen atom, an aliphatic hydrocarbon group, an aliphatic sulfonic acid, or an aliphatic sulfonate. And at least one of X _{1 to} X ₄ is —COOM ₂ , and M ₂ represents a hydrogen atom, an alkali metal, ammonium or an organic amine,
m and n each independently represents a number of 1 or more.   The water-soluble polymer is hypophosphorous acid or a salt thereof, and at least one monomer selected from the group consisting of a monoethylenically unsaturated carboxylic acid or a salt thereof and a monoethylenically unsaturated carboxylic acid derivative or a salt thereof. The polishing liquid composition according to claim 1, which is a copolymer obtained by polymerizing the composition.   The water-soluble polymer is selected from the group consisting of bis (poly-2-carboxyethyl) phosphinic acid, phosphinocarboxylic acid copolymers, salts thereof, and combinations thereof. The polishing liquid composition as described in 2. above.   The content of the structural unit represented by the formula (I) in all the structural units constituting the water-soluble polymer is 1 mol% or more and 30 mol% or less. Polishing liquid composition.   6. The polishing composition according to claim 1, wherein the substrate to be polished is a magnetic disk substrate having a Ni—P-containing layer.   The polishing composition according to any one of claims 1 to 6, wherein the pH is 0.5 or more and 4.0 or less.   The polishing liquid composition according to claim 1 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 at least one of the polishing pad and the substrate to be polished is A method for manufacturing a substrate, comprising a step of moving and polishing.   The polishing liquid composition according to claim 1 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 at least one of the polishing pad and the substrate to be polished is A method for polishing a substrate, comprising moving and polishing.