JP2022063246A - Polishing liquid composition - Google Patents

Abstract

To provide a polishing liquid composition which is capable of reducing scratches and waves in a substrate surface after polishing, while ensuring an adequate polishing rate.SOLUTION: A polishing liquid composition contains silica particles (component A), a compound (component B), an acid (component C) and an aqueous medium. The component B has a pH of 3 or less, and is a compound (component B1) including a repeat unit derived from a maleic acid or maleic anhydride as a main chain, and having a hydrophobic group in at least one end of it, or a compound (component B2) including a repeat unit derived from a maleic acid, maleic anhydride or maleic acid alkyl ester as a main chain, and having a hydrophobic group in at least one end of it.SELECTED DRAWING: None

Description

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

In recent years, magnetic disk drives have become smaller and larger in capacity, and higher recording densities are required. In order to increase the recording density, the unit recording area is reduced, and the detection sensitivity of the weakened magnetic signal is improved. Therefore, technological development for lowering the floating height of the magnetic head is underway. For magnetic disk substrates, in order to reduce the levitation of the magnetic head and secure the recording area, improvement of smoothness and flatness represented by reduction of surface roughness, waviness, and end face sagging (roll-off) and scratching, The demand for defect reduction represented by the reduction of protrusions and pits is becoming stricter.

In response to such a requirement, for example, Patent Document 1 discloses a polishing liquid composition for a synthetic quartz glass substrate containing a colloidal silica dispersion liquid and a polyacrylic acid polymer (Examples of the same document).
Patent Document 2 discloses an aqueous dispersion for chemical mechanical polishing containing an organic acid, a nitrogen-containing heterocyclic compound, an oxidizing agent, abrasive grains such as colloidal silica, and a water-soluble polymer such as polycarboxylic acid. Has been done.
Patent Document 3 describes at least one of a repeating unit of a polymer containing at least two carboxylic acid functional groups, an oxidant for promoting barrier removal, abrasive grains, and an inhibitor for reducing removal of wiring metal. A chemical mechanical planarization composition comprising a carboxylic acid polymer having one is disclosed.

Japanese Unexamined Patent Publication No. 2010-17841 Japanese Unexamined Patent Publication No. 2010-69550 JP-A-2015-123757

With the increase in capacity of magnetic disk drives, the required characteristics for the surface quality of the substrate are becoming more stringent, and the development of a polishing liquid composition capable of further reducing scratches and waviness on the surface of the substrate is required. Further, in general, there is a trade-off relationship between polishing speed and scratch, and there is a problem that if one is improved, the other is deteriorated. In this regard, even if the polymers described in Patent Documents 1 to 3 are used, they are not yet sufficiently satisfactory.

Therefore, the present disclosure provides a polishing liquid composition capable of reducing scratches and waviness on the surface of a substrate after polishing while ensuring a polishing rate, and a method for manufacturing a magnetic disk substrate and a method for polishing the substrate using the same.

式（Ｉ）中、Ｒ¹及びＲ²はそれぞれ独立に、水素原子又は疎水性基であり、ｍ及び
ｎは０～２０であり、ｍ＋ｎ＝１～２０の関係を満たす。但し、Ｒ¹及びＲ²は同時に水素原子とはならない。
式（ＩＩ）中、Ｒ³及びＲ⁴はそれぞれ独立に、水素原子又は疎水性基であり、ｋ及びｌは０～２０であり、ｋ＋ｌ＝１～２０の関係を満たす。但し、Ｒ³及びＲ⁴は同時に水素原子とはならない。Ｒ⁵及びＲ⁶はそれぞれ独立に、水素原子又は炭素数１～５のアルキル基である。但し、Ｒ⁵及びＲ⁶は同時に水素原子とはならない。 In one embodiment, the present disclosure contains silica particles (component A), a compound (component B), an acid (component C), and an aqueous medium, and the component B is the following formula (I) or the following formula. The present invention relates to a polishing liquid composition, which is a compound represented by (II) and has a pH of 3 or less.

In formula (I), R ¹ and R ² are independently hydrogen atoms or hydrophobic groups, m and n are 0 to 20, and the relationship of m + n = 1 to 20 is satisfied. However, R ¹ and R ² do not become hydrogen atoms at the same time.
In formula (II), R ³ and R ⁴ are independently hydrogen atoms or hydrophobic groups, k and l are 0 to 20, and the relationship of k + l = 1 to 20 is satisfied. However, R ³ and R ⁴ do not become hydrogen atoms at the same time. R ⁵ and R ⁶ are independently hydrogen atoms or alkyl groups having 1 to 5 carbon atoms. However, R ⁵ and R ⁶ do not become hydrogen atoms at the same time.

The present disclosure relates to a method for manufacturing a magnetic disk substrate, which comprises a step of polishing the substrate to be polished using the polishing liquid composition of the present disclosure in another aspect.

The present disclosure includes, in other embodiments, polishing a substrate to be polished using the polishing liquid composition of the present disclosure, wherein the substrate to be polished is a substrate used for manufacturing a magnetic disk substrate, polishing the substrate. Regarding the method.

According to the polishing composition of the present disclosure, in one or more embodiments, it is possible to achieve the effect of reducing scratches and waviness on the surface of the substrate after polishing while ensuring the polishing rate.

In the present disclosure, when a polishing liquid composition containing silica particles, a predetermined compound, an acid, and an aqueous medium and having a pH of 3 or less is used for polishing a magnetic disk substrate, the surface of the substrate after polishing is maintained while ensuring the polishing rate. Based on the finding that scratches and waviness can be reduced.

That is, in one embodiment, the present disclosure contains silica particles (component A), a compound (component B), an acid (component C), and an aqueous medium, and the component B is the above formula (I) or. It relates to a polishing liquid composition (hereinafter, also referred to as “the polishing liquid composition of the present disclosure”) which is a compound represented by the above formula (II) and has a pH of 3 or less.

The details of the mechanism of effect manifestation of the present disclosure are not clear, but it is inferred as follows.
The compound which is the component B is adsorbed on the surface of the substrate by the interaction between the hydrophobic group at the end thereof and the surface of the substrate. On the other hand, the main chain containing a repeating unit derived from maleic acid or maleic anhydride or a repeating unit derived from maleic acid, maleic anhydride or an alkyl maleic acid ester chelate the nickel atom on the surface of the substrate. As a result, it is considered that the solubility of the substrate surface is improved and the polishing speed is improved. Further, since the substrate surface can be uniformly etched by the component B, it is considered that scratches on the substrate surface after polishing can be reduced. In addition, it is considered that the etching of the substrate makes the outermost layer of the substrate fragile and soft, which makes it easier to cut the softened part smoothly when it comes into contact with the polishing pad, improving the flatness and reducing the waviness. ..
However, the present disclosure may not be construed as being limited to these mechanisms.

In the present disclosure, scratches on the surface of the substrate can be detected by, for example, an optical defect inspection device, and can be quantitatively evaluated as the number of scratches. Specifically, the number of scratches can be evaluated by the method described in Examples.
In the present disclosure, the "waviness" of the substrate means the unevenness of the surface of the substrate having a wavelength longer than the roughness. In the present disclosure, for example, the swell observed at a wavelength of 60 to 160 μm is referred to as “ultra-short wavelength swell”, and for example, the swell observed at a wavelength of 50 to 500 μm is referred to as “short wavelength swell”. By reducing the waviness (ultra-short wavelength waviness, short wavelength waviness) of the substrate surface after polishing, the floating height of the magnetic head can be lowered in the magnetic disk drive, and the recording density of the magnetic disk can be improved. Become. Due to the recent increase in recording density of magnetic disks, "VHF swell" has become a particularly important index, and it has been found that it affects not only the improvement of recording density but also the durability during long-term use. There is. The undulations on the surface of the substrate (ultra-short wavelength undulations, short wavelength undulations) can be measured, for example, by the method described in Examples. In the present disclosure, "reduction of waviness" means reduction of at least one of very high frequency waviness and short wavelength waviness.

[Silica particles (component A)]
The silica particles (hereinafter, also referred to as “component A”) contained in the polishing liquid composition of the present disclosure include colloidal silica, fumed silica, pulverized silica, and the like from the viewpoint of ensuring the polishing speed and reducing scratches and waviness. Surface-modified silica and the like can be mentioned, but colloidal silica is preferable. The component A may be one kind or a combination of two or more kinds.

The average particle size based on the scattering intensity distribution measured by the dynamic light scattering method of component A is preferably 1 nm or more, more preferably 5 nm or more, and more preferably 10 nm or more from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. Further preferable, and from the same viewpoint, 500 nm or less is preferable, 300 nm or less is more preferable, 100 nm or less is further preferable, 70 nm or less is further preferable, and 40 nm or less is further preferable. From the same viewpoint, the average particle size based on the scattering intensity distribution measured by the dynamic light scattering method of component A is preferably 1 nm or more and 500 nm or less, more preferably 1 nm or more and 300 nm or less, and further preferably 1 nm or more and 100 nm or less. It is more preferably 5 nm or more and 70 nm or less, and further preferably 10 nm or more and 40 nm or less. In the present disclosure, the "average particle size based on the scattering intensity distribution measured by the dynamic light scattering method of silica particles" is the average grain size based on the scattering intensity distribution measured at a detection angle of 90 ° in the dynamic light scattering method. The diameter (average secondary particle size). Specifically, the average particle size of the silica particles can be determined by the method described in Examples.

The content of the component A in the polishing liquid composition of the present disclosure is preferably 0.1% by mass or more, more preferably 1% by mass or more, and 3% by mass or more in terms of SiO ₂ from the viewpoint of improving the polishing speed. Is more preferable, and from the viewpoint of scratch and waviness reduction, 20% by mass or less is preferable, 15% by mass or less is more preferable, and 10% by mass or less is further preferable in terms of SiO ₂ . Further, the content of the component A in the polishing liquid composition of the present disclosure is preferably 0.1% by mass or more and 20% by mass or less in terms of SiO ₂ from the viewpoint of ensuring the polishing speed and reducing scratches and waviness. It is more preferably 1% by mass or more and 15% by mass or less, and further preferably 3% by mass or more and 10% by mass or less. When the component A is composed of two or more kinds of silica particles, the content of the component A means the total content thereof.

[Compound (Component B)]
The polishing liquid composition of the present disclosure contains a compound (hereinafter, also referred to as “component B”). From the viewpoint of ensuring the polishing rate and reducing scratches and waviness, the component B contains, in one or more embodiments, a repeating unit derived from maleic acid or maleic anhydride as the main chain, and at least one end thereof. Mainly composed of a compound having a hydrophobic group (hereinafter, also referred to as "terminal hydrophobic group") (hereinafter, also referred to as "component B1"), and a repeating unit derived from maleic acid, maleic anhydride or maleic acid alkyl ester. It is at least one selected from compounds contained as a chain and having a terminal hydrophobic group at at least one end thereof (hereinafter, also referred to as “component B2”). The component B may be one kind or a combination of two or more kinds.

(Terminal hydrophobic group)
The terminal hydrophobic group is not particularly limited, but is selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic ring-containing hydrocarbon group from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. At least one selected is listed. Examples of the aliphatic hydrocarbon group include a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, or a decyl group. The group is mentioned. Examples of the alicyclic hydrocarbon group include a cyclopentyl group and a cyclohexyl group. Examples of the aromatic ring-containing hydrocarbon group include a phenyl group, a benzyl group, an alkylbenzyl group having 1 to 3 carbon atoms, a naphthyl group, and an alkylnaphthyl group having 1 to 3 carbon atoms.
Among these, from the viewpoint of ensuring the polishing rate and reducing scratches and waviness, an aromatic ring-containing hydrocarbon group is preferable, a benzyl group or an alkylbenzyl group having 1 to 3 carbon atoms is more preferable, and an alkylbenzyl group having 1 to 3 carbon atoms is more preferable. It is an alkylbenzyl group of 1 to 3. Examples of the alkylbenzyl group having 1 to 3 carbon atoms include a methylbenzyl group and the like. In the present disclosure, the "terminal" refers to the end of the polymer backbone. The terminal hydrophobic group is not, in one or more embodiments, a structural unit (repeating unit) of the polymer.

(Repeating unit derived from maleic acid or maleic anhydride)
When the component B is the component B1, the content of the repeating unit derived from maleic acid or maleic anhydride in all the constituent units constituting the component B1 ensures the polishing rate in one or more embodiments. Further, from the viewpoint of reducing scratches and waviness, 90 mol% or more is preferable, 95 mol% or more is more preferable, and 100 mol% is further preferable.

Examples of the component B1 include a compound represented by the following formula (I) from the viewpoint of ensuring the polishing speed and reducing scratches and waviness.

In formula (I), R ¹ and R ² are independently hydrogen atoms or hydrophobic groups, m and n are 0 to 20, and the relationship of m + n = 1 to 20 is satisfied. However, R ¹ and R ² do not become hydrogen atoms at the same time. In addition, m and n indicate the average number of added moles, respectively. Examples of the hydrophobic group include the same as the above-mentioned terminal hydrophobic group.
In the formula (I), m is preferably 20 or less, more preferably 15 or less, still more preferably 10 or less, from the viewpoint of ensuring storage stability in the polishing liquid composition, ensuring polishing speed, and reducing scratches and waviness. .. From the same viewpoint, m is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. From the same viewpoint, m is preferably 1 or more and 20 or less, more preferably 2 or more and 15 or less, and further preferably 3 or more and 10 or less.
In the formula (I), n is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, from the viewpoint of ensuring storage stability and polishing characteristics in the polishing liquid composition.

The sequence of each structural unit constituting the component B1 may be random, block, or graft.

(Repeating unit derived from maleic acid, maleic anhydride or maleic acid alkyl ester)
When the component B is the component B2, the content of the repeating unit derived from maleic acid, maleic anhydride or maleic acid alkyl ester in all the constituent units constituting the component B2 is, in one or more embodiments, the content of the repeating unit. From the viewpoint of ensuring the polishing rate and reducing scratches and waviness, 90 mol% or more is preferable, 95 mol% or more is more preferable, and 100 mol% is further preferable.

Examples of the component B2 include a compound represented by the following formula (II) from the viewpoint of ensuring the polishing speed and reducing scratches and waviness.

In formula (II), R ³ and R ⁴ are independently hydrogen atoms or hydrophobic groups, k and l are 0 to 20, and the relationship of k + l = 1 to 20 is satisfied. However, R ³ and R ⁴ do not become hydrogen atoms at the same time. R ⁵ and R ⁶ are independently hydrogen atoms or alkyl groups having 1 to 5 carbon atoms. However, R ⁵ and R ⁶ do not become hydrogen atoms at the same time. In addition, k and l indicate the average number of added moles. Examples of the hydrophobic group include the same as the above-mentioned terminal hydrophobic group.
In the formula (II), R ⁵ and R ⁶ are independently hydrogen atoms or alkyl groups having 1 to 5 carbon atoms, for example, methyl group and ethyl, from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. Group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, cyclopentyl group, preferably methyl group, ethyl group, propyl group, It is an isopropyl group or a butyl group, more preferably a methyl group, an ethyl group, or a propyl group. However, R ⁵ and R ⁶ do not become hydrogen atoms at the same time.
In the formula (II), a part of the repeating unit having an average addition mole number of k may be formed by dehydration condensation of two adjacent carboxyl groups (−COOH) to form a ring structure.
In the formula (II), k is preferably 20 or less, more preferably 15 or less, still more preferably 10 or less, from the viewpoint of ensuring storage stability in the polishing liquid composition, ensuring polishing speed, and reducing scratches and waviness. .. From the same viewpoint, k is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. From the same viewpoint, k is preferably 1 or more and 20 or less, more preferably 2 or more and 15 or less, and further preferably 3 or more and 10 or less.
In the formula (II), l is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, from the viewpoint of ensuring storage stability and polishing characteristics in the polishing liquid composition.

The sequence of each structural unit constituting the component B2 may be random, block, or graft.

The component B is preferably a compound represented by the above formula (I) or the above formula (II) from the viewpoint of ensuring the polishing speed and reducing scratches and waviness.

The content of the repeating unit represented by the following formula in all the constituent units constituting the component B is preferably 80 mol% or more, preferably 85 mol% or more from the viewpoint of improving the solubility of the polymer in one or more embodiments. % Or more is more preferable, and 90 mol% or more is further preferable.

In the present disclosure, as the content (mol%) of a certain constituent unit in all the constituent units constituting the component B, depending on the synthesis conditions, all the constituent units charged in the reaction vessel in all the steps of the synthesis of the component B are used. The amount of the compound (mol%) for introducing the structural unit charged in the reaction vessel in the compound for introduction may be used. Further, in the present disclosure, when the component B contains two or more kinds of constituent units, as the constituent ratio (molar ratio) of the two constituent units, depending on the synthesis conditions, the component B is charged into the reaction tank in all the steps of the synthesis of the component B. The compound amount ratio (molar ratio) for introducing the two constituent units may be used.

Component B may further have other structural units other than those derived from maleic acid, maleic anhydride or maleic acid alkyl esters, as long as the effects of the present disclosure are not significantly impaired. The content of the other constituent units in all the constituent units constituting the component B is preferably 10 mol% or less, more preferably 5 mol% or less, and substantially, from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. 0 mol% is more preferable.

The component B contains, in one or more embodiments, a repeating unit derived from polymaleic acid, maleic acid or maleic anhydride having a xylene group (methylbenzyl group) at at least one end as a main chain, and at least one of them. A polymer having a xylene group (methylbenzyl group) at the end, and a polymer containing a repeating unit derived from maleic acid, maleic anhydride or diethyl maleate, and having a xylene group (methylbenzyl group) at at least one end thereof. At least one selected from.

As a method for producing the component B1, for example, maleic acid or maleic anhydride is dissolved in a solvent such as xylene, a polymerization initiator is added, and the reaction is started. It can be produced by reacting for a predetermined time to obtain a predetermined compound.
As a method for producing the component B2, for example, maleic acid or maleic anhydride and a maleic acid alkyl ester are dissolved in a solvent such as xylene, a polymerization initiator is added, and the reaction is started. It can be produced by reacting for a predetermined time to obtain a predetermined compound.

The weight average molecular weight of the component B is preferably 2,000 or less, more preferably 1,500 or less, and more preferably 1,500 or less from the viewpoints of ensuring storage stability in the polishing liquid composition, ensuring polishing speed, and reducing scratches and waviness. It is more preferably 000 or less, and from the same viewpoint, 200 or more is preferable, 300 or more is more preferable, and 500 or more is further preferable. From the same viewpoint, the weight average molecular weight of the component B is preferably 200 or more and 2,000 or less, more preferably 300 or more and 1,500 or less, and further preferably 500 or more and 1,000 or less. In the present disclosure, the weight average molecular weight is a value measured by gel permeation chromatography (GPC) under the conditions described in Examples. When the weight average molecular weight of the component B is 200 or more and 2,000 or less, the component B can exist stably under strong acid (for example, pH 3 or less) and can improve the storage stability of the polishing liquid composition having a pH of 3 or less. Conceivable.

The nickel dissolution acceleration constant K of the component B is preferably 105 or more, more preferably 107 or more, still more preferably 110 or more, from the viewpoint of improving the polishing rate.
In the present disclosure, the nickel dissolution promotion constant K is represented by the following formula (III), and can be specifically measured by the method described in Examples.
K = S / S ₀ × 100 (III)
In formula (III), S ₀ is the aqueous solution obtained by immersing the nickel-containing substrate to be polished in 100 g of an aqueous solution containing 0.5% by mass of hydrogen peroxide and 2.0% by mass of phosphoric acid at 25 ° C. for 120 minutes. The amount of nickel dissolved in (ng) is shown. S is in the aqueous solution when the substrate to be polished is immersed in 100 g of an aqueous solution containing 0.1% by mass of component B, 0.5% by mass of hydrogen hydrogen and 2.0% by mass of phosphoric acid at 25 ° C. for 120 minutes. The amount of dissolved nickel (ng) is shown.

The content of component B in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and 0, from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. It is more preferably 8.08% by mass or more, and from the same viewpoint, 0.1% by mass or less is preferable, 0.09% by mass or less is more preferable, and 0.08% by mass or less is further preferable. From the same viewpoint, the content of component B in the polishing liquid composition of the present disclosure is preferably 0.001% by mass or more and 0.1% by mass or less, more preferably 0.005% by mass or more and 0.09% by mass or less. It is preferable, and more preferably 0.008% by mass or more and 0.08% by mass or less. When the component B is a combination of two or more kinds, the content of the component B is the total content thereof.

The mass ratio of component B to component A in the polishing liquid composition of the present disclosure (content of component B / content of component A) is 0.001 or more from the viewpoint of ensuring polishing speed and reducing scratches and waviness. Is more preferable, 0.002 or more is further preferable, 0.003 or more is further preferable, 0.004 or more is further preferable, and from the same viewpoint, 0.02 or less is preferable, 0.015 or less is more preferable. 0.01 or less is more preferable. From the same viewpoint, the mass ratio (content of component B / content of component A) in the polishing liquid composition of the present disclosure is preferably 0.001 or more and 0.02 or less, and 0.002 or more and 0.015 or less. Is more preferable, 0.003 or more and 0.01 or less is further preferable, and 0.004 or more and 0.01 or less is further preferable.

[Acid (component C)]
The polishing liquid composition of the present disclosure contains an acid (component C). In the present disclosure, the use of an acid includes the use of an acid or a salt thereof. The component C may be one kind or a combination of two or more kinds.

The component C includes, for example, an inorganic acid such as nitrate, sulfuric acid, sulfite, persulfate, hydrochloric acid, perchloric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphate, tripolyphosphate, and amide sulfate; organic phosphoric acid and organic phosphon. Organic acids such as acids and carboxylic acids; and the like. Among them, at least one selected from inorganic acids and organic phosphonic acids is preferable from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. As the inorganic acid, at least one selected from nitric acid, sulfuric acid, hydrochloric acid, perchloric acid and phosphoric acid is preferable, and phosphoric acid is more preferable. As the organic phosphonic acid, at least one selected from 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), and diethylenetriaminepenta (methylenephosphonic acid) is used. Preferably, HEDP is more preferred. Examples of the salt of these acids include salts of the above acids and at least one selected from metals, ammonia and alkylamines. Examples of the metal include metals belonging to groups 1 to 11 of the periodic table.

The content of the component C in the polishing liquid composition of the present disclosure is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. By mass or more is more preferable, and from the same viewpoint, 5% by mass or less is preferable, 4% by mass or less is more preferable, and 3% by mass or less is further preferable. From the same viewpoint, the content of component C in the polishing liquid composition of the present disclosure is preferably 0.01% by mass or more and 5% by mass or less, more preferably 0.1% by mass or more and 4% by mass or less, and 1% by mass. % Or more and 3% by mass or less are more preferable. When the component C is a combination of two or more kinds, the content of the component C means the total content thereof.

The mass ratio C / A of component C to component A in the polishing liquid composition of the present disclosure (content of component C / content of component A) is 0 from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. .002 or more is preferable, 0.02 or more is more preferable, 0.08 or more is further preferable, 0.2 or more is further preferable, and from the same viewpoint, 1 or less is preferable, 0.8 or less is more preferable. 0.6 or less is more preferable. From the same viewpoint, the mass ratio C / A in the polishing liquid composition of the present disclosure is preferably 0.002 or more and 1 or less, more preferably 0.02 or more and 0.8 or less, and 0.08 or more and 0.6 or less. Is more preferable, and 0.2 or more and 0.6 or less is further preferable.

[Aqueous medium]
Examples of the aqueous medium contained in the polishing liquid composition of the present disclosure include distilled water, ion-exchanged water, water such as pure water and ultrapure water, or a mixed solvent of water and a solvent. Examples of the solvent include a solvent that can be mixed with water (for example, alcohol such as ethanol). When the aqueous medium is a mixed solvent of water and a solvent, the ratio of water to the entire mixed medium may not be particularly limited as long as the effects of the present disclosure are not hindered, and from the viewpoint of economic efficiency, for example. , 95% by mass or more is preferable, 98% by mass or more is more preferable, and substantially 100% by mass is further preferable. From the viewpoint of surface cleanliness of the substrate to be polished, ion-exchanged water and ultrapure water are preferable as the water-based medium. The content of the aqueous medium in the polishing liquid composition of the present disclosure can be the residue excluding the component A, the component B, the component C, and if necessary, an optional component described later.

[Oxidizing agent (component D)]
The polishing liquid composition of the present disclosure may further contain an oxidizing agent (hereinafter, also referred to as “component D”) from the viewpoint of ensuring the polishing speed and further reducing scratches and waviness. The component D may be one kind or a combination of two or more kinds.

The component D may be, for example, a peroxide, a permanganic acid or a salt thereof, a chromium acid or a salt thereof, a peroxo acid or a salt thereof, an oxygen acid or the like from the viewpoint of ensuring the polishing speed and further reducing scratches and waviness. Examples thereof include salts, metal salts, nitrates and sulfuric acids. Among these, at least one selected from hydrogen peroxide, iron nitrate (III), peracetic acid, ammonium peroxodisulfate, iron (III) sulfate and iron (III) sulfate is preferable, and the substrate to be polished is from the viewpoint of improving the polishing speed. Hydrogen peroxide is more preferable from the viewpoint of preventing metal ions from adhering to the surface of the above and from the viewpoint of easy availability.

When the polishing liquid composition of the present disclosure contains the component D, the content of the component D in the polishing liquid composition of the present disclosure is 0.01 from the viewpoint of ensuring the polishing speed and further reducing scratches and waviness. Mass% or more is preferable, 0.05% by mass or more is more preferable, 0.1% by mass or more is further preferable, 4% by mass or less is preferable, 2% by mass or less is more preferable, and 1.5% by mass or less is preferable. More preferred. From the same viewpoint, the content of the component D in the polishing liquid composition of the present disclosure is preferably 0.01% by mass or more and 4% by mass or less, more preferably 0.05% by mass or more and 2% by mass or less, and 0. It is more preferably 1% by mass or more and 1.5% by mass or less. When the component D is a combination of two or more kinds, the content of the component D means the total content thereof.

The polishing liquid composition of the present disclosure can further contain at least one selected from a heterocyclic aromatic compound, an aliphatic amine compound and an alicyclic amine compound from the viewpoint of further reducing scratches. Each of these components will be described below.

[Heterocyclic aromatic compound (component E)]
The polishing liquid composition of the present disclosure may further contain a heterocyclic aromatic compound (including a salt thereof) (component E) from the viewpoint of further reducing scratches. The component E may be one kind or a combination of two or more kinds.

From the viewpoint of further reducing scratches, the component E is preferably a heterocyclic aromatic compound containing two or more nitrogen atoms in the heterocycle, and more preferably has three or more nitrogen atoms in the heterocycle. Preferably, 3 or more and 9 or less are more preferable, 3 or more and 5 or less are further preferable, and 3 or 4 is further preferable.

As component E, in one or more embodiments, 1,2,4-triazole, 3-amino-1,2,4-triazole, 5-amino-1,2,4-triazole, 3-mercapto-1 , 2,4-Triazole, 1H-tetrazole, 5-aminotetrazole, 1H-benzotriazole (BTA), 1H-tolyltriazole, 2-aminobenzotriazole, 3-aminobenzotriazole, and alkyl or amine substitutions thereof. At least one selected from the body is preferred. Examples of the alkyl group of the alkyl substituent include a lower alkyl group having 1 to 4 carbon atoms, and in one or more embodiments, a methyl group and an ethyl group. Examples of the amine substituent include 1- [N, N-bis (hydroxyethylene) aminomethyl] benzotriazole and 1- [N, N-bis (hydroxyethylene) aminomethyl] triltriazole in one or more embodiments. Can be mentioned.
Among these, 1H-benzotriazole (BTA), 1H-tolyltriazole, 2-aminobenzotriazole, and 3-aminobenzotriazole are more preferable as the component E from the viewpoint of further reduction of scratches. (BTA) is more preferred.

When the polishing liquid composition of the present disclosure contains the component E, the content of the component E in the polishing liquid composition of the present disclosure is preferably 0.005% by mass or more, preferably 0, from the viewpoint of further reducing scratches. 0.01% by mass or more is more preferable, 0.02% by mass or more is further preferable, 10% by mass or less is preferable, 5% by mass or less is more preferable, 1% by mass or less is further preferable, and 0.2% by mass or less. Is more preferable. From the same viewpoint, the content of the component E in the polishing liquid composition of the present disclosure is preferably 0.005% by mass or more and 10% by mass or less, more preferably 0.01% by mass or more and 5% by mass or less, and 0. It is more preferably 02% by mass or more and 1% by mass or less, and further preferably 0.02% by mass or more and 0.2% by mass or less. When the component E is a combination of two or more kinds, the content of the component E means the total content thereof.

[Aliphatic amine compound or alicyclic amine compound (component F)]
The polishing liquid composition of the present disclosure may further contain an aliphatic amine compound or an alicyclic amine compound (component F) from the viewpoint of further reducing scratches. From the viewpoint of further reducing scratches, the number of nitrogen atoms in the molecule of the component F or the total number of amino groups or imino groups is preferably 2 or more and 4 or less. The component F may be one kind or a combination of two or more kinds.

As the aliphatic amine compound, in one or more embodiments, from the viewpoint of further reducing scratches, ethylenediamine, N, N, N', N'-tetramethylethylenediamine, 1,2-diaminopropane, 1, 3-Diaminopropane, 1,4-diaminobutane, hexamethylenediamine, 3- (diethylamino) propylamine, 3- (dibutylamino) propylamine, 3- (methylamino) propylamine, 3- (dimethylamino) propylamine , N-Aminoethylethanolamine, N-aminoethylisopropanolamine, and N-aminoethyl-N-methylethanolamine, preferably at least one selected from, preferably N-aminoethylethanolamine, N-aminoethylisopropanolamine, and At least one selected from N-aminoethyl-N-methylethanolamine is more preferable, and N-aminoethylethanolamine (AEA) is even more preferable.

The alicyclic amine compound includes, in one or more embodiments, piperazine, 2-methylpiperazine, 2,5-dimethylpiperazine, 1-amino-4-methylpiperazine, N, from the viewpoint of further reducing scratches. -At least one selected from methylpiperazine and hydroxyethylpiperazine (HEP) is preferable, and hydroxyethylpiperazine (HEP) is more preferable.

When the polishing liquid composition of the present disclosure contains the component F, the content of the component F in the polishing liquid composition of the present disclosure is preferably 0.005% by mass or more, preferably 0, from the viewpoint of further reducing scratches. 0.01% by mass or more is more preferable, 0.02% by mass or more is further preferable, 10% by mass or less is preferable, 5% by mass or less is more preferable, 1% by mass or less is further preferable, and 0.1% by mass or less. Is more preferable. From the same viewpoint, the content of the component F in the polishing liquid composition of the present disclosure is preferably 0.005% by mass or more and 10% by mass or less, more preferably 0.01% by mass or more and 5% by mass or less, and 0. It is more preferably 02% by mass or more and 1% by mass or less, and further preferably 0.02% by mass or more and 0.1% by mass or less. When the component F is a combination of two or more kinds, the content of the component F means the total content thereof.

[Other ingredients]
The polishing liquid composition of the present disclosure may further contain other components, if necessary, in one or more embodiments. Examples of other components include polymer compounds other than component B, thickeners, dispersants, rust inhibitors, basic substances, surfactants, solubilizers and the like.

[Contents of component A, component B and component C in the polishing liquid composition]
The content of component A, component B and component C in the polishing liquid composition of the present disclosure is the content of component A in one or more embodiments from the viewpoint of ensuring the polishing rate and reducing scratches and waviness. However, in terms of SiO ₂ , it is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, further. It is preferably 10% by mass or less, and the content of component B is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, still more preferably 0.008% by mass or more, and preferably. Is 0.1% by mass or less, more preferably 0.09% by mass or less, further preferably 0.08% by mass or less, and the content of the component C is preferably 0.01% by mass or more, more preferably. Is 0.1% by mass or more, more preferably 1% by mass or more, and preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less.

[PH of polishing liquid composition]
The pH of the polishing liquid composition of the present disclosure is 3 or less, preferably 2.5 or less, more preferably 2 or less, still more preferably less than 2, from the viewpoint of ensuring the polishing rate and further reducing scratches. 1.9 or less is more preferable, 1.8 or less is further preferable, 1.7 or less is further preferable, 1.6 or less is further preferable, and from the same viewpoint, 0.5 or more is preferable, and 0.8 or more is preferable. Is more preferable, and 1.2 or more is further preferable. From the same viewpoint, the pH of the polishing liquid composition of the present disclosure is preferably 0.5 or more and 3 or less, more preferably 0.5 or more and 2.5 or less, further preferably 0.5 or more and 2 or less, and 0.8. More than 1.9 or less is more preferable. The pH can be adjusted by using the above-mentioned acid (component C), a known pH adjuster, or the like. In the present disclosure, the pH is the pH of the polishing liquid composition at 25 ° C. and can be measured using a pH meter. For example, the pH is set to a value 2 minutes after the electrode of the pH meter is immersed in the polishing liquid composition. be able to.

[Manufacturing method of polishing liquid composition]
The polishing liquid composition of the present disclosure contains, for example, component A, component B, component C and an aqueous medium, and optionally optional components (component D, component E, component F and other components) by a known method. Can be manufactured by That is, the present disclosure relates to a method for producing an abrasive liquid composition, which comprises, in other embodiments, at least a step of blending component A, component B, component C and an aqueous medium. In the present disclosure, "blending" means mixing component A, component B, component C and an aqueous medium, and optionally optional components (component D, component E, component F and other components) simultaneously or in any order. Including doing. The component A may be mixed in the state of a concentrated slurry, or may be diluted with water or the like and then mixed. When the component A is composed of a plurality of types of silica particles, the plurality of types of silica particles can be blended simultaneously or separately. When the component B is composed of a plurality of types of compounds, the plurality of types of compounds can be blended simultaneously or separately. When the component C is composed of a plurality of types of acids, the plurality of types of acids can be blended simultaneously or separately. The formulation can be performed using, for example, a mixer such as a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. The preferable blending amount of each component in the method for producing the polishing liquid composition can be the same as the preferable content of each component in the polishing liquid composition of the present disclosure described above.

In the present disclosure, the "content of each component in the polishing liquid composition" means the content of each component at the time of use, that is, at the time when the polishing liquid composition is started to be used for polishing.
The content of each component in the polishing liquid composition in the present disclosure can be regarded as the blending amount of each component in one or more embodiments.

The polishing liquid composition of the present disclosure may be stored and supplied in a concentrated state as long as its storage stability is not impaired. In this case, it is preferable in that the manufacturing and transportation costs can be further reduced. The concentrate of the polishing liquid composition of the present disclosure may be appropriately diluted with the above-mentioned aqueous medium at the time of use, if necessary. The dilution ratio is not particularly limited as long as the content (at the time of use) of each of the above-mentioned components can be secured after dilution, and can be, for example, 10 to 100 times.

[Abrasive liquid kit]
The present disclosure relates to a kit for producing the polishing liquid composition of the present disclosure (hereinafter, also referred to as "polishing liquid kit of the present disclosure") in another aspect. The polishing liquid kit of the present disclosure contains, for example, a silica dispersion containing component A and an aqueous medium and an aqueous additive solution containing component B and component C in a state in which they are not mixed with each other, and these are mixed at the time of use. , A polishing liquid kit (two-component polishing liquid composition), which is diluted with an aqueous medium as needed. The aqueous medium contained in the silica dispersion may be the entire amount or a part of the aqueous medium used for preparing the polishing liquid composition. The additive aqueous solution may contain a part of an aqueous medium used for preparing the polishing liquid composition. The silica dispersion and the additive aqueous solution may each contain the above-mentioned optional components (components D to F and other components), if necessary. According to the polishing liquid kit of the present disclosure, it is possible to obtain a polishing liquid composition capable of reducing scratches and waviness on the surface of the substrate after polishing while ensuring the polishing speed.

[Substrate to be polished]
The substrate to be polished is a substrate used for manufacturing a magnetic disk substrate in one or more embodiments. In one or more embodiments, after the step of polishing the surface of the substrate to be polished with the polishing liquid composition of the present disclosure, a magnetic disk substrate is formed by forming a magnetic layer on the surface of the substrate by sputtering or the like. Can be manufactured.

Materials of the substrate to be polished preferably used in the present disclosure include metals or semi-metals such as silicon, aluminum, nickel, tungsten, copper, tantalum and titanium, alloys thereof, glass, glassy carbon and amorphous materials. 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. Above all, it is suitable for a substrate to be polished containing metals such as aluminum, nickel, tungsten and copper and alloys containing these metals as main components. As the substrate to be polished, for example, a Ni-P plated aluminum alloy substrate, a glass substrate such as crystallized glass, reinforced glass, aluminosilicate glass, and aluminoborosilicate glass are more suitable, and Ni-P plated. Aluminum alloy substrates are more suitable. In the present disclosure, the "Ni-P plated aluminum alloy substrate" means an electroless Ni-P plated surface after grinding the surface of an aluminum alloy base material.

Examples of the shape of the substrate to be polished include a shape having a flat portion such as a disk shape, a plate shape, a slab shape, and a prism shape, and a shape having a curved surface portion such as a lens. Above all, a disk-shaped substrate to be polished is suitable. In the case of a disk-shaped substrate to be polished, the outer diameter thereof is, for example, about 2 to 95 mm, and the thickness thereof is, for example, about 0.4 to 2 mm.

[Manufacturing method of magnetic disk board]
Generally, a magnetic disk is manufactured by polishing a substrate to be polished that has undergone a grinding process through a rough polishing process and a finish polishing process, and then converting it into a magnetic disk in a recording unit forming process. The polishing liquid composition in the present disclosure can be used in a polishing step of polishing a substrate to be polished, preferably a finish polishing step, in a method for manufacturing a magnetic disk substrate. That is, the present disclosure includes, in other embodiments, a step of polishing the substrate to be polished using the polishing liquid composition of the present disclosure (hereinafter, also referred to as "polishing step using the polishing liquid composition of the present disclosure"). , The present invention relates to a method for manufacturing a magnetic disk substrate (hereinafter, also referred to as “the substrate manufacturing method of the present disclosure”). The substrate manufacturing method of the present disclosure is particularly suitable for a method for manufacturing a magnetic disk substrate for a perpendicular magnetic recording method.

In the polishing step using the polishing liquid composition of the present disclosure, in one or a plurality of embodiments, the polishing liquid composition of the present disclosure is supplied to the polishing target surface of the substrate to be polished, and the polishing pad is brought into contact with the polishing target surface. This is a step of moving at least one of the polishing pad and the substrate to be polished to polish. Further, in the polishing step using the polishing liquid composition of the present disclosure, in one or more other embodiments, the substrate to be polished is formed on a platen to which a polishing pad such as a non-woven organic polymer-based polishing cloth is attached. This is a step of polishing the substrate to be polished by moving the platen and the substrate to be polished while sandwiching and supplying the polishing liquid composition of the present disclosure to the polishing machine.

When the polishing step of the substrate to be polished is performed in multiple steps, the polishing step using the polishing liquid composition of the present disclosure is preferably performed in the second and subsequent steps, and is performed in the final polishing step or the finish polishing step. Is more preferable. At that time, in order to avoid mixing of the abrasive material and the polishing liquid composition in the previous process, different polishing machines may be used, and when different polishing machines are used, each polishing process is to be polished. It is preferable to clean the substrate. Further, the polishing liquid composition of the present disclosure can also be used in the circulation polishing in which the used polishing liquid is reused. The polishing machine is not particularly limited, and a known polishing machine for polishing a substrate can be used.

The polishing pad used in the present disclosure is not particularly limited, and for example, a suede type, a non-woven fabric type, a polyurethane independent foam type, or a two-layer type in which these are laminated can be used, and the polishing speed can be used. From the viewpoint of, a suede type polishing pad is preferable.

The polishing load in the polishing step using the polishing liquid composition of the present disclosure is preferably 5.9 kPa or more, more preferably 6.9 kPa or more, still more preferably 7.5 kPa or more, from the viewpoint of ensuring the polishing speed. From the viewpoint of scratch and waviness reduction, it is preferably 20 kPa or less, more preferably 18 kPa or less, and further preferably 16 kPa or less. In the manufacturing method of the present disclosure, the polishing load means the pressure of the surface plate applied to the polished surface of the substrate to be polished during polishing. Further, the polishing load can be adjusted by applying air pressure or a weight to at least one of the surface plate and the substrate to be polished.

The supply rate of the polishing liquid composition of the present disclosure in the polishing process using the polishing liquid composition of the present disclosure is preferably 0.05 mL / min or more and 15 mL / min per 1 cm ² of the substrate to be polished from the viewpoint of reducing scratches and waviness. Minutes or less, more preferably 0.06 mL / min or more and 10 mL / min or less, still more preferably 0.07 mL / min or more and 1 mL / min or less, still more preferably 0.07 mL / min or more and 0.5 mL / min or less. ..

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

According to the substrate manufacturing method of the present disclosure, by using the polishing liquid composition of the present disclosure, a high-quality magnetic disk substrate with reduced scratches and waviness on the surface of the substrate after polishing can be produced in high yield and productivity. The effect that it can be manufactured well can be achieved.

[Polishing method]
The present disclosure relates to a method for polishing a substrate (hereinafter, also referred to as “the polishing method of the present disclosure”), which comprises polishing the substrate to be polished using the polishing liquid composition of the present disclosure as another aspect. By using the polishing method of the present disclosure, it is possible to obtain an effect that a high-quality magnetic disk substrate with reduced scratches and waviness on the surface of the substrate after polishing can be produced in high yield and with high productivity. As described above, examples of the substrate to be polished in the polishing method of the present disclosure include those used for manufacturing a magnetic disk substrate, and among them, a substrate used for manufacturing a magnetic disk substrate for a longitudinal magnetic recording method is preferable. The polishing method and conditions in the polishing method of the present disclosure can be the same as the method and conditions of the substrate manufacturing method of the present disclosure described above.

Polishing a substrate to be polished using the polishing liquid composition of the present disclosure is, in one or more embodiments, supplying the polishing liquid composition of the present disclosure to the surface to be polished of the substrate to be polished, and the surface to be polished. The polishing pad is brought into contact with the surface, and at least one of the polishing pad and the substrate to be polished is moved for polishing, or a platen to which a polishing pad such as a non-woven organic polymer-based polishing cloth is attached is used. While sandwiching the polishing substrate and supplying the polishing liquid composition of the present disclosure to the polishing machine, the platen or the substrate to be polished is moved to polish the substrate to be polished.

Hereinafter, the present disclosure will be described in more detail by way of examples, but these are exemplary and the present disclosure is not limited to these examples.

1. 1. Compounds B1 to B6
The following compounds were used as the compounds B1 to B6 shown in Table 1.
B1: Maleic acid-based polymer having a hydrophobic group at the terminal (I) [maleic acid / maleic anhydride copolymer having a xylene group (methylbenzyl group) at the terminal, weight average molecular weight, synthesized as described below. : 700] (In formula (I), R ¹ = hydrogen atom, R ² = xylene group (methylbenzyl group), m and n are "(4) Average number of moles added" in "3. Measurement of each parameter" described later. Measurement of m, n, k, l, and molar ratios ”).
B2: Maleic acid-based polymer (II) having a hydrophobic group at the terminal [maleic acid / diethyl maleic acid copolymer having a xylene group (methylbenzyl group) at the terminal, weight average molecular weight, synthesized as described below. : 700] (In formula (II), R ³ = hydrogen atom, R ⁴ = xylene group (methyl benzyl group), R ⁵ = ethyl group, R ⁶ = ethyl group, k and l are described later in "3. Each parameter". As shown in "(4) Measurement of average added molar number m, n, k, l, and molar ratio" of "Measurement").
B3: Polyacrylic acid [Made by Kao Corporation, weight average molecular weight: 30,000]
B4: Acrylic acid / maleic acid copolymer (molar ratio: 83/17) [Made by Kao Corporation, trade name: Kaosera 2110, weight average molecular weight: 24,000]
B5: Styrene sulfonic acid / maleic acid copolymer (molar ratio: 50/50) [manufactured by AkzoNobel, trade name: YE-920, weight average molecular weight: 20,000]
B6: Maleic acid / isobutylene copolymer (molar ratio 50/50) [manufactured by Kuraray, trade name: Isoban 104, weight average molecular weight: 60,000]

<Synthesis example of component B1>
Maleic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) in a three-necked glass flask with a capacity of 300 mL, which is connected with a stirring blade, a thermometer, a Dimroth condenser, a 50 mL volume dropping funnel, a nitrogen gas blowing tube, and a bubbler tube. , 30 g) and xylene (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., first-class reagent, 100 g) and heated to 100 ° C. using an oil bath to dissolve. Next, benzoyl peroxide (5 g manufactured by Tokyo Chemical Industry Co., Ltd.) is dissolved in xylene (20 g) and added to the above-mentioned dropping funnel. Nitrogen gas is flowed, tap water is flowed through a Dimroth condenser, and benzoyl peroxide / xylene is dropped from the above dropping funnel at a uniform rate over 60 minutes while rotating with a stirring blade. After the dropping, the mixture is stirred at 100 ° C. for 3 hours and then cooled to 25 ° C. Since the polymer is obtained as a precipitate, the precipitate is taken out and 100 g of water is added to dissolve it. Next, xylene was removed under reduced pressure using an evaporator to obtain component B1.
<Synthesis example of component B2>
Maleic anhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) in a three-necked glass flask with a capacity of 300 mL, which is connected with a stirring blade, a thermometer, a Dimroth condenser, a 50 mL volume drip funnel, a nitrogen gas blow tube, and a bubbler tube. , 30 g), diethyl maleate (manufactured by Tokyo Chemical Industry Co., Ltd., 2 g) and xylene (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., reagent first grade, 100 g), and heated to 100 ° C. to dissolve using an oil bath. .. Next, benzoyl peroxide (5 g manufactured by Tokyo Chemical Industry Co., Ltd.) is dissolved in xylene (20 g) and added to the above-mentioned dropping funnel. Nitrogen gas is flowed, tap water is flowed through a Dimroth condenser, and benzoyl peroxide / xylene is dropped from the above dropping funnel at a uniform rate over 60 minutes while rotating with a stirring blade. After the dropping, the mixture is stirred at 100 ° C. for 3 hours and then cooled to 25 ° C. Since the polymer is obtained as a precipitate, the precipitate is taken out and 100 g of water is added to dissolve it. Next, xylene was removed under reduced pressure using an evaporator to obtain component B2.

2. 2. Preparation of polishing liquid composition (Examples 1 to 6, Examples 10 to 15, Comparative Examples 1 to 5)
(Abrasive liquid compositions of Examples 1 to 6, Examples 10 to 15, and Comparative Examples 1 to 5)
Mixing and stirring component A (colloidal silica), component B or non-component B (compounds B1 to B6 shown in Table 1), component C (phosphoric acid), component D (hydrogen peroxide), and ion-exchanged water. The polishing liquid compositions of Examples 1 to 6, Examples 10 to 15 and Comparative Examples 1 to 5 shown in Table 2 were prepared. The content (effective amount) of each component in each polishing liquid composition is as shown in Table 2. The content of the ion-exchanged water is the residue excluding the component A, the component B or the non-component B, the component C, and the component D.
(Abrasive liquid compositions of Examples 7 to 9 and Examples 16 to 18)
Component A (colloidal silica), component B (compounds B1 and B2 shown in Table 1), component C (phosphoric acid), component D (hydrogen peroxide), additives (component E: BTA, component F: HEP, etc.) Ingredients: BisS / PhS) and ion-exchanged water were mixed and stirred to prepare the polishing liquid compositions of Examples 7 to 9 and Examples 16 to 18 shown in Table 2. The content (effective amount) of each component in each polishing liquid composition is as shown in Table 2. The content of the ion-exchanged water is the residue excluding component A, component B, component C, component D, and additives (component E, component F, and other components).

In the preparation of each polishing liquid composition, the following were used as the component C and the additives (components D to F and other components).
Phosphoric acid [manufactured by Wako Pure Chemical Industries, Ltd., special grade] (ingredient C)
Hydrogen peroxide solution [concentration 35% by mass, manufactured by ADEKA Corporation] (component D)
BTA [1,2,3-benzotriazole, manufactured by Tokyo Chemical Industry Co., Ltd.] (Ingredient E)
HEP [N-hydroxyethylpiperazine, manufactured by Wako Pure Chemical Industries, Ltd.] (Component F)
BisS / PhS [bisphenol S / phenol sulfonic acid formalin condensate, manufactured by Konishi Chemical Industry Co., Ltd., ratio: 20/80, weight average molecular weight: 5,000] (other components)

3. 3. Measurement of each parameter (1) Average particle size of colloidal silica (component A) Component A (coloidal silica) and component C (phosphoric acid) used in the preparation of the polishing liquid composition are added to ion-exchanged water and stirred. By doing so, a standard sample was prepared. The contents of component A and component C in the standard sample were 1% by mass and 2% 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 by a dynamic light scattering device (DLS-6500 manufactured by Otsuka Electronics Co., Ltd.) according to the instructions attached by the same manufacturer. The particle size was determined to be 50% of the total, and the average particle size of the colloidal silica was used. The results are shown in Table 2.

(2) Weight average molecular weight of the compound (component B and non-component B) The weight average molecular weight of the component B and the non-component B was measured by the gel permeation chromatography (GPC) method under the following conditions. The results are shown in Tables 1 and 2.
<Measurement conditions>
Column: TSKgel GMPWXL + TSKgel GMPWXL (manufactured by Tosoh)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 7/3 (volume ratio)
Temperature: 40 ° C
Flow velocity: 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)

(3) Measurement of pH The pH of the polishing liquid composition was measured at 25 ° C. using a pH meter (manufactured by DKK-TOA CORPORATION), and the value 2 minutes after the electrode was immersed in the polishing liquid composition was adopted. .. The results are shown in Table 2.

(4) Measurement of average number of added moles m, n, k, l and molar ratio [Measurement of average number of added moles m, n and molar ratio of component B1]
20 mg of the measurement sample (component B1) was dissolved in 10 mL of methanol, and measurement was performed by liquid chromatography-mass spectrometry (LC / MS) under the following conditions. As a result of the measurement, the component B1 is a compound having m = 3, n = 1 in the formula (I), a compound having m = 4, n = 0 in the formula (I), and m = 5, n in the formula (I). It was a mixture of the compound of = 0 and the compound of m = 6 and n = 0 in the formula (I). When the content ratios of m and n of the component B1 are calculated from the respective peak intensities, the content ratio of the repeating unit having the average number of added moles of m in the component B1 is 98.5 mol%, and the average number of added moles is n. The content ratio of the repeating unit was 1.5 mol%.
[Measurement of average added mole number k, l and molar ratio of component B2]
20 mg of the measurement sample (component B2) was dissolved in 10 mL of methanol, and measurement was performed by liquid chromatography-mass spectrometry (LC / MS) under the following conditions. As a result of the measurement, the component B2 is a compound of k = 3, l = 1 in the formula (II), a compound of k = 4, l = 1 in the formula (II), and k = 5, l in the formula (II). It was a mixture with the compound of = 1. When the content ratios of k and l of the component B2 are calculated from the respective peak intensities, the content ratio of the repeating unit in the component B2 in which the average number of added moles is k is 96 mol%, and the content ratio of the repeating unit in which the average number of added moles is l is l. The content ratio of was 4 mol%.
<Analysis conditions>
Equipment: Thermo Q-Exactive
Column: L-column2 ODS (2.1 x 150 mm)
A: 10 mM ammonium acetate aqueous solution B: 10 mM ammonium acetate methanol solution oven temperature: 40 ° C.
Injection volume: 5 μL
Flow rate: 0.2 mL / min
B% (min): 5 (0) -5 (3) -100 (15) -100 (20) -5 (20.1) -5 (30)
Detector: MS (ESI) positive, negative
Scan range: m / z 500-1000

4. Polishing Method Using the polishing liquid compositions of Examples 1 to 18 and Comparative Examples 1 to 5 prepared as described above, the following polishing substrate was polished under the polishing conditions shown below. Then, the polishing speed and the number of scratches were measured. The results are shown in Table 2.

[Substrate to be polished]
As the substrate to be polished, a substrate obtained by roughly polishing a Ni-P-plated aluminum alloy substrate with a polishing liquid composition containing an alumina abrasive in advance was used. The substrate to be polished had a thickness of 0.8 mm, an outer diameter of 95 mm, an inner diameter of 25 mm, and a center line average roughness Ra measured by an AFM (Digital Instrument NanoScope IIIa Multi Mode AFM) was 1 nm. The ratio of Ni to P in the Ni-P plating was 88:12 in terms of mass ratio.

[Polishing conditions]
Polishing tester: "Double-sided 9B polishing machine" manufactured by Speedfam
Polishing pad: Fujibo suede type (foam layer: polyurethane elastomer, thickness 0.9 mm, average opening diameter 10 μm)
Abrasive liquid composition supply amount: 100 mL / min (supply rate per 1 cm ² of substrate to be polished: 0.076 mL / min)
Lower platen rotation speed: 32.5 rpm
Polishing load: 13.0 kPa
Polishing time: 6 minutes Number of substrates: 10

5. Evaluation [Evaluation of polishing speed]
The weight of each substrate before and after polishing was measured using a measurement (“BP-210S” manufactured by Sartorius), and the amount of mass loss was determined from the change in mass of each substrate. The value obtained by dividing the average mass reduction amount of all 10 sheets by the polishing time was defined as the polishing rate, and was calculated by the following formula. The measurement results of the polishing rate are shown in Table 2 as relative values with Comparative Example 1 as 100.
Mass reduction (g) = {mass before polishing (g) -mass after polishing (g)}
Polishing speed (mg / min) = mass loss (mg) / polishing time (min)

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

[Evaluation of VHF and short wavelength swell]
Three substrates were arbitrarily selected from the ten substrates after polishing, and both sides of each selected substrate were measured at arbitrary four points (24 points in total) under the following conditions. The average value of the measured values at the 24 points was calculated as the ultra-short wavelength swell and the short-wavelength swell of the substrate. Then, the relative values with Comparative Example 1 as 100 are shown in Table 2.
<Measurement conditions>
Measuring machine: New View 7300 (manufactured by Zygo)
Lens: 2.5x Zoom: 0.5x VHF region: 60-160μm
Short wavelength region: 50-500 μm
Analysis software: Zygo Metro Pro (manufactured by Zygo)

[Evaluation of solubility]
By diluting a nickel standard solution (Ni1000) manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. with ion-exchanged water, nickel aqueous solutions having nickel concentrations of 10 ppm, 20 ppm, and 50 ppm are prepared, and measurements are performed under the following analytical conditions. This created a calibration curve.
Next, as described in Examples, 100 g of an aqueous solution I (pH 1.6, the balance is ion-exchanged water) containing 0.1% by mass of component B, 0.5% by mass of hydrogen peroxide, and 2.0% by mass of phosphoric acid. One substrate to be polished (surface area: 131.9 cm ² ) was immersed in an open system for 120 minutes at 25 ° C. and normal pressure so that the liquid was evenly contacted with the entire substrate without stirring. After 120 minutes had passed, the substrate was taken out, the amount of nickel contained in the remaining aqueous solution I was measured under the following analytical conditions, and the nickel concentration in the aqueous solution I was measured by making corrections using the prepared calibration curve. .. From the obtained nickel concentration and the mass of the aqueous solution I, the amount of nickel dissolved (ng) in the aqueous solution I was calculated and used as S (ng).
Further, an experiment was conducted under the same conditions as above for 100 g of an aqueous solution II (pH 1.6, the balance is ion-exchanged water) containing 0.5% by mass of hydrogen hydrogen and 2.0% by mass of phosphoric acid, and the solution was added to the aqueous solution II. The amount of dissolved nickel (ng) was calculated and used as S ₀ (ng).
Then, the nickel dissolution promotion constant K was calculated from the following formula, and the relative values with Comparative Example 1 as 100 are shown in Table 2.
K = S / S ₀ × 100
<Analysis conditions>
Equipment: ICP-OES 5110 (Agilent Technologies)
Lead time: 5s
Auxiliary gas: 1.0 L / min
RF power: 1.2 kW
Nebulizer flow rate: 0.7 L / min
Stabilization time: 15s
Plasma flow rate: 12.0 L / min
Observation mode: Axial observation element: Ni
Observation wavelength: 231.604 nm

As shown in Table 2 above, the polishing liquid compositions of Examples 1 to 18 effectively reduce scratches and waviness while ensuring the polishing speed as compared with the polishing liquid compositions of Comparative Examples 1 to 5. rice field.

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

Claims (10)

It contains silica particles (component A), a compound (component B), an acid (component C), and an aqueous medium.
Component B is a compound represented by the following formula (I) or the following formula (II).
A polishing liquid composition having a pH of 3 or less.

In formula (I), R ¹ and R ² are independently hydrogen atoms or hydrophobic groups, m and n are 0 to 20, and the relationship of m + n = 1 to 20 is satisfied. However, R ¹ and R ² do not become hydrogen atoms at the same time.
In formula (II), R ³ and R ⁴ are independently hydrogen atoms or hydrophobic groups, k and l are 0 to 20, and the relationship of k + l = 1 to 20 is satisfied. However, R ³ and R ⁴ do not become hydrogen atoms at the same time. R ⁵ and R ⁶ are independently hydrogen atoms or alkyl groups having 1 to 5 carbon atoms. However, R ⁵ and R ⁶ do not become hydrogen atoms at the same time. The polishing liquid composition according to claim 1, wherein the component B has a nickel dissolution promoting constant K represented by the following formula (III) of 105 or more.
K = S / S ₀ × 100 (III)
In formula (III), S ₀ is the aqueous solution obtained by immersing the nickel-containing substrate to be polished in 100 g of an aqueous solution containing 0.5% by mass of hydrogen hydrogen and 2.0% by mass of phosphoric acid at 25 ° C. for 120 minutes. The amount of nickel dissolved (ng) in the medium is shown. S is in the aqueous solution when the substrate to be polished is immersed in 100 g of an aqueous solution containing 0.1% by mass of component B, 0.5% by mass of hydrogen hydrogen and 2.0% by mass of phosphoric acid at 25 ° C. for 120 minutes. The amount of dissolved nickel (ng) is shown. The polishing liquid composition according to claim 1 or 2, wherein the weight average molecular weight of the component B is 200 or more and 2,000 or less. The polishing liquid composition according to any one of claims 1 to 3, wherein the content of the component B is 0.001% by mass or more and 0.1% by mass or less. The polishing liquid composition according to any one of claims 1 to 4, wherein the average particle size based on the scattering intensity distribution measured by the dynamic light scattering method of the component A is 100 nm or less. The polishing liquid composition according to any one of claims 1 to 5, further containing an oxidizing agent. The polishing liquid composition according to any one of claims 1 to 6, further comprising at least one selected from a heterocyclic aromatic compound, an aliphatic amine compound and an alicyclic amine compound. The polishing liquid composition according to any one of claims 1 to 7, wherein the polishing liquid composition is a polishing liquid composition for a magnetic disk substrate. A method for manufacturing a magnetic disk substrate, which comprises a polishing step of polishing the substrate to be polished using the polishing liquid composition according to any one of claims 1 to 8. A method for polishing a substrate, which comprises polishing the substrate to be polished using the polishing liquid composition according to any one of claims 1 to 8, wherein the substrate to be polished is a substrate used for manufacturing a magnetic disk substrate. ..