JP2008101132A - Polishing fluid composition for memory hard disk substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing fluid composition for a memory hard disk substrate which can be suitably used for reducing nano scratchs on the surface of the memory hard disk substrate. <P>SOLUTION: The polishing fluid composition for a memory hard disk substrate comprises water, a colloidal silica, a gelation inhibitor and at least either one of an inorganic acid and an organic phosphonic acid, wherein the gelation inhibitor is an organic acid free of a nitrogen atom and the gelation inhibiting potentials of the gelation inhibitor exhibits a relation of (V2-V1)≤1,000, wherein V1 is a viscosity (mPa s) of a fluid at 25°C, containing 20 wt.% of the colloidal silica and 0.1 wt.% of the gelation inhibitor and 1.5 of pH adjusted by sulfuric acid, and V2 is the viscosity (mPa s) of the fluid at 25°C after allowing the fluid to stand for 24 hrs at 80°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  In recent years, memory hard disk drives are required to be smaller and have higher capacities. For this reason, a method of increasing the recording capacity per sheet is performed by reducing the unit recording area of the memory hard disk. When the unit recording area is reduced, the flying height of the magnetic head needs to be further reduced. With this, the quality of the memory hard disk substrate surface after polishing is further improved, for example, the surface roughness and scratches on the substrate surface are further improved. Reduction is required.

  In order to improve the quality of the substrate surface, a gelling inhibitor such as phosphonic acid, a polishing liquid composition containing colloidal silica and ammonium nitrate (Patent Documents 1 to 3), alkali metal ions, abrasive grains, carboxylic acid, oxidizing agent, and A polishing liquid composition containing a gelation inhibitor (Patent Document 4) and a polishing liquid composition containing silicon dioxide, an oxidizing agent and an organic acid (Patent Document 5) have been proposed.

However, since further increase in recording capacity is required, it cannot be said that the conventional polishing composition can sufficiently reduce scratches and the like, and a polishing composition that can sufficiently reduce scratches is required.
Japanese Patent No. 3653133 JP 2000-13858 A JP-A-8-34179 International Publication No. 01/079377 Pamphlet JP 2002-294225 A

  Therefore, an object of the present invention is to provide a polishing composition for a memory hard disk substrate that can reduce nano-scratches on the surface of the memory hard disk substrate, and a method for producing a memory hard disk substrate using the same.

The present invention
A polishing composition for a memory hard disk substrate comprising water, colloidal silica, a gelation inhibitor, and at least one of an inorganic acid and an organic phosphonic acid,
The gelation inhibitor is an organic acid containing no nitrogen atom,
A polishing composition for a memory hard disk substrate, wherein the gelation inhibitory ability of the gelation inhibitor exhibits a relationship of (V2-V1) ≦ 1000;
[V1 represents the viscosity (mPa · s) at 25 ° C. of a solution containing 20 wt% colloidal silica and 0.1 wt% gelation inhibitor and adjusted to pH 1.5 with sulfuric acid, and V2 is The viscosity (mPa · s) at 25 ° C. after leaving the solution at 80 ° C. for 24 hours is shown. ],as well as,
A method for producing a memory hard disk substrate, comprising a step of polishing a substrate using a polishing liquid composition, wherein the polishing liquid composition is the polishing liquid composition for a memory hard disk substrate of the present invention. ,
About.

  According to the present invention, since the aggregation of colloidal silica can be suppressed, nano-scratches on the substrate surface in the substrate polishing step can be reduced. In addition, since the polishing liquid composition of the present invention is excellent in storage stability, a substrate with high surface quality can be produced without gelation of the polishing liquid composition even when stored for a long period of time.

(Polishing composition for memory hard disk substrate)
The polishing composition for a memory hard disk substrate of the present invention is a polishing composition for a memory hard disk substrate containing water, colloidal silica, a gelation inhibitor, and at least one of an inorganic acid and an organic phosphonic acid. The gelation inhibitor is an organic acid containing no nitrogen atom, and the gelation inhibitory ability of the gelation inhibitor is a polishing liquid composition for a memory hard disk substrate showing a relationship of (V2−V1) ≦ 1000 (hereinafter referred to as “a gelation inhibitor”). “V2−V1” is described as “ΔV”). According to the polishing liquid composition of the present invention, since aggregation of colloidal silica in the polishing liquid composition can be suppressed, nano scratches on the substrate surface can be reduced. In addition, the polishing composition of the present invention has excellent storage stability because the gelation inhibitory ability of the gelation inhibitor exhibits ΔV ≦ 1000.

  In the present invention, the colloidal silica may be a commercially available one or may be obtained by a known production method or the like produced from an aqueous silicic acid solution. The colloidal silica may be in the form of a sol or a gel.

  The average particle size of the primary particles of the colloidal silica is preferably 1 to 50 nm, more preferably 1 to 35 nm, and still more preferably 3 to 30 nm, from the viewpoint of reducing the surface roughness and improving the polishing rate. In addition, the average particle size (average particle size of the secondary particles) when primary particles are aggregated to form secondary particles is 5 to 100 nm from the viewpoint of reducing the surface roughness and improving the polishing rate. More preferably, it is 5-80 nm, More preferably, it is 5-50 nm. The average particle diameter of the primary particles of the colloidal silica can be determined by measurement using a transmission electron microscope. The average particle diameter of the secondary particles of the colloidal silica can be calculated as a volume average particle diameter using laser scattered light.

  The content of the colloidal silica in the polishing composition is preferably 0.1 to 40% by weight, more preferably 0.5 to 30% by weight, from the viewpoint of further reducing nanoscratches and improving the polishing rate. Preferably it is 0.5 to 20% by weight.

  In the present invention, the gelation inhibitor is an organic acid containing no nitrogen atom, and specific examples thereof include oxalic acid, maleic acid, fumaric acid, methanesulfonic acid, formic acid, malonic acid, citric acid, glycolic acid. And acetic acid. Among these, at least one organic acid selected from the group consisting of oxalic acid, maleic acid, fumaric acid and methanesulfonic acid is preferable because nanoscratches can be further reduced and storage stability can be further improved. .

  In the present invention, the gelation inhibitory ability of the gelation inhibitor shows a relationship of ΔV ≦ 1000. Generation | occurrence | production of the nano scratch of the board | substrate at the time of grinding | polishing can be effectively reduced as the gelation inhibitory ability of the said gelation inhibitor is (DELTA) V <= 1000. Although the mechanism for reducing nanoscratches by the polishing liquid composition of the present invention is not clear, the gelation inhibitor in the polishing liquid composition interacts with the silanol groups of the silica particles to suppress contact between the silica particles. It is presumed that the aggregation of silica particles is suppressed. Moreover, since the polishing liquid composition of the present invention is suppressed from gelation of the polishing liquid composition, it exhibits excellent storage stability even in a long-term storage state such as during transportation. In addition, said V1 and V2 are measured by the method as described in the Example mentioned later.

  In order to further reduce nanoscratches on the substrate surface and further improve the storage stability, the V2 is preferably 1 to 2000 mPa · s, more preferably 1 to 1800 mPa · s, and still more preferably 1 to 1500 mPa. -S. For the same reason, the ΔV is preferably 500 or less, more preferably 100 or less, and still more preferably 50 or less.

  The content of the gelation inhibitor in the polishing composition is preferably 0.01 to 10% by weight, more preferably 0.01 to 8% by weight, from the viewpoint of further reducing nanoscratches and improving the polishing rate. More preferably, it is 0.05 to 5% by weight.

  As said inorganic acid and organic phosphonic acid, the compound whose pK1 is 2 or less is preferable from a viewpoint of making the reduction of a nanoscratch and the improvement of a grinding | polishing speed compatible. In addition, since the nanoscratch can be further reduced, a compound having a pK1 of 1.5 or less is more preferable, more preferably 1 or less, and particularly preferably a compound exhibiting strong acidity that cannot be quantified by pK1. Specific examples of the inorganic acid include nitric acid, sulfuric acid, sulfurous acid, persulfuric acid, hydrochloric acid, perchloric acid, phosphoric acid, phosphonic acid, phosphinic acid, pyrophosphoric acid, tripolyphosphoric acid, amidosulfuric acid and the like. Specific examples of the organic phosphonic acid include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), 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-dicarboxy-1,2-diphosphonic acid, methanehydroxyphosphonic acid, 2-phosphonobutane-1,2-dicarboxylic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid, α- And methylphosphonosuccinic acid. Among the inorganic acids, sulfuric acid, hydrochloric acid, and perchloric acid are more preferable, and sulfuric acid is more preferable. A particularly excellent gelation suppressing effect can be exhibited by a combination of sulfuric acid and the organic acid (gelation inhibitor). Among the organic phosphonic acids, HEDP, aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), and diethylenetriaminepenta (methylenephosphonic acid) are preferable. These may be used alone or in combination of two or more. Here, pK1 indicates a logarithmic value of the reciprocal of the first acid dissociation constant (25 ° C.) of an organic compound or an inorganic compound, and pK1 of each compound is, for example, revised 4th edition Chemical Handbook (Basic) II, p316 -325 (edited by the Chemical Society of Japan).

  The inorganic acid and organic phosphonic acid may use salts thereof. Examples of the inorganic acid and organic phosphonic acid salts include salts with metals, ammonium, alkylammonium, organic amines, and the like. Specific examples of the metal include metals belonging to 1A, 1B, 2A, 2B, 3A, 3B, 4A, 6A, 7A, or Group 8 of the periodic table (long period type). Among these, from the viewpoint of further reducing nanoscratches, a metal belonging to Group 1A or a salt with ammonium is preferable.

  The content of the inorganic acid and the organic phosphonic acid in the polishing composition of the present invention is preferably 0.01% by weight or more from the viewpoint of further reducing nanoscratches and improving the polishing rate. Further, from the viewpoint of the influence on the human body and prevention of corrosion of the polishing apparatus, it is preferably 20% by weight or less, more preferably 15% by weight or less, and further preferably 10% by weight or less. Therefore, from the viewpoint of further reduction of nanoscratches and working environment, the content of the inorganic acid and the organic phosphonic acid is preferably 0.01 to 10% by weight, more preferably 0.01 to 8% by weight, still more preferably. Is 0.01 to 5% by weight.

  Examples of the water used in the polishing composition of the present invention include distilled water, ion exchange water, and ultrapure water. From the viewpoint of surface cleanliness of the substrate to be polished, ion-exchanged water and ultrapure water are preferable, and ultrapure water is particularly preferable. The water content in the polishing composition is preferably 0.1 to 99% by weight, more preferably 0.1 to 95% by weight. In addition, the polishing liquid composition of this invention may contain organic solvents, such as alcohol, in the range which does not inhibit the effect of this invention.

  The pH of the polishing composition of the present invention can be appropriately determined according to the material of the substrate to be polished, etc., but is preferably 0.1 to 6.5 from the viewpoint of further reducing nanoscratches and improving the polishing rate. Preferably it is 0.5-4, More preferably, it is 0.5-2. The pH can be adjusted with a pH adjusting agent.

  The polishing composition of the present invention may further contain an oxidizing agent. Examples of the oxidizing agent include peroxides, metal peroxo acids or salts thereof, oxygen acids or salts thereof, and the like. Further, the oxidizing agent is roughly classified into an inorganic oxidizing agent and an organic oxidizing agent according to its structure, but it can further improve the polishing rate, is easily available, and is further handled such as solubility in water. Since it becomes easy, an inorganic type oxidizing agent is preferable. Examples of the inorganic oxidant include hydrogen peroxide, alkali metal or alkaline earth metal peroxide, peroxocarbonate, peroxosulfuric acid or salt thereof, peroxophosphoric acid or salt thereof, peroxoborate, peroxochromate Permanganate, halogen-containing oxyacid salt, inorganic acid metal salt, and the like. Examples of the alkali metal or alkaline earth metal peroxide include sodium peroxide, potassium peroxide, calcium peroxide, barium peroxide, magnesium peroxide and the like. Examples of the peroxo carbonate include sodium peroxo carbonate and Examples of the peroxosulfuric acid or salt thereof include ammonium peroxodisulfate, sodium peroxodisulfate, potassium peroxodisulfate, and peroxomonosulfuric acid. Examples thereof include sodium phosphate, potassium peroxophosphate and ammonium peroxophosphate. Examples of the peroxoborate include sodium peroxoborate and potassium peroxoborate, and the peroxochromate. To the sodium potassium peroxo chromic acid and peroxo chromic acid and the like. Examples of the permanganate include sodium permanganate and potassium permanganate. Examples of the oxyacid salt containing halogen include sodium perchlorate, potassium perchlorate, sodium hypochlorite, and periodate. Examples thereof include sodium acid, potassium periodate, sodium iodate, and potassium iodate, and examples of the inorganic acid metal salt include iron (III) chloride and iron (III) sulfate. On the other hand, examples of the organic oxidizing agent include percarboxylic acids, peroxides, and organic acid iron (III) salts. Examples of the percarboxylic acids include peracetic acid, formic acid, and perbenzoic acid. Examples of the peroxide include t-butyl peroxide and cumene peroxide. The organic acid iron (III ) Salts include iron (III) citrate and the like. Among these, hydrogen peroxide, sodium peroxoborate, sodium iodate, and potassium iodate are preferable from the viewpoint of improving the polishing rate. These oxidizing agents may be used alone or in combination of two or more.

  The content of the oxidizing agent in the polishing liquid composition is preferably 0.01 to 20% by weight, more preferably 0.01 to 15% by weight, from the viewpoint of further reducing nanoscratches and improving the polishing rate. Preferably it is 0.01 to 10 weight%.

  The polishing liquid composition of the present invention may further contain a bactericidal agent, an antibacterial agent, a thickener, a dispersant, a rust inhibitor, a basic substance, a surfactant, a pH adjuster and the like. The content of these components in the polishing composition is preferably 10% by weight or less, more preferably 8% by weight or less, and still more preferably 6% by weight or less from the viewpoint of polishing characteristics.

(Method for preparing polishing liquid composition)
The method for preparing the polishing composition of the present invention is not limited at all, and can be prepared by mixing at least one of the gelation inhibitor, the colloidal silica and water, and an inorganic acid and an organic phosphonic acid. The dispersion of the colloidal silica is not particularly limited, and can be performed using a homomixer, a homogenizer, an ultrasonic disperser, a stirrer such as a wet ball mill, or the like.

  The pH of the polishing composition may be adjusted to a predetermined pH after mixing the components, or may be adjusted before mixing. The pH can be adjusted with the pH adjusting agent or the like.

(Method for manufacturing memory hard disk substrate)
The method for producing a memory hard disk substrate of the present invention is a method for producing a memory hard disk substrate including a step of polishing a substrate (substrate to be polished) using the polishing composition of the present invention. According to the substrate manufacturing method of the present invention, a memory hard disk substrate with reduced nano-scratches on the substrate surface can be manufactured because it includes a polishing step using the polishing composition of the present invention.

  In the polishing step, the polishing composition of the present invention is supplied to the polishing surface of the substrate, the polishing pad is brought into contact with the polishing surface, and the polishing pad or the substrate is moved while applying a predetermined polishing pressure (polishing load). Etc. In addition, the said grinding | polishing can be performed with a conventionally well-known grinding | polishing apparatus.

  The polishing composition may be used as it is, or diluted if it is a concentrated solution. In the case of diluting the concentrated liquid, the dilution ratio is not particularly limited, and can be appropriately determined according to the concentration of each component in the concentrated liquid (abrasive content, etc.), polishing conditions, and the like.

  The polishing pad is not particularly limited, and a conventionally known polishing pad can be used. Examples of the polishing pad include a suede type, a non-woven fabric type, a polyurethane closed-cell foam type, or a two-layer type polishing pad in which these are laminated.

The polishing load means the pressure of the surface plate applied to the polishing surface of the substrate to be polished during polishing. The polishing load in the production method of the present invention is preferably 10 to 500 g / cm ² , more preferably 10 to 400 g / cm ² , and still more preferably 30 to 300 g / cm, from the viewpoint of further reducing nanoscratches and improving productivity. cm ² . The polishing load can be adjusted by applying air pressure or weight to the surface plate or the substrate.

The supply rate of the polishing composition is preferably from 0.01 to 0.25 mL / min, more preferably from 0.025 to 0.2 mL / min per 1 cm ^{2 of the} substrate to be polished, from the viewpoint of improving cost and polishing rate. More preferably, it is 0.05-0.15 mL / min.

  Examples of the material of the substrate to be polished include metals, metalloids such as silicon, aluminum, nickel, tungsten, copper, tantalum, and titanium, or alloys thereof, glassy materials such as glass, glassy carbon, and amorphous carbon, alumina, Examples thereof include ceramic materials such as silicon dioxide, silicon nitride, tantalum nitride, and titanium carbide, and resins such as polyimide resin. Among these, a substrate to be polished containing a metal such as aluminum, nickel, tungsten, copper, or an alloy containing these metals as a main component is preferable. For example, a Ni—P plated aluminum alloy substrate or a glass substrate such as crystallized glass or tempered glass is suitable, and a Ni—P plated aluminum alloy substrate is particularly suitable.

  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. 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.

(Preservation test)
Colloidal silica (SiO ₂ , average particle size of primary particles 28 nm, manufactured by Dupont) and organic acid shown in Table 1 below are mixed, and a silica solution adjusted to pH 1.5 with sulfuric acid (colloidal silica 20% by weight, gelation suppression) 40 g of 0.1 wt% of the agent was placed in a 50 cc screw tube, and the viscosity (V1) of the solution was measured (25 ° C.). Next, the solution was allowed to stand at 80 ° C. for 24 hours in a thermostatic bath, and then the appearance was visually observed, and the viscosity (V2) of the solution was measured (25 ° C.). The obtained viscosity and visual observation results are shown in Table 1 below. In Table 1 below, “◯” indicates the case where the liquid level is tilted when the screw tube is tilted, and “X” indicates the case where the liquid level is not tilted even when the screw tube is tilted. The viscosity was measured with a B-type viscometer (manufactured by Tokyo Keiki Co., Ltd.).

  As shown in Table 1, it can be seen that the gelation of the silica solution can be suppressed by using the gelation inhibitor used in the present invention.

(Examples 1-5)
As Examples 1 to 5, at least one of the additives (gelation inhibitor) shown in Table 2 below, the following colloidal silica, hydrogen peroxide water and ion-exchanged water, and sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid and HEDP Was used to prepare a polishing composition having the composition shown in Table 2 below.

(Comparative Examples 1-6)
As Comparative Examples 1 to 6, polishing liquid compositions having the compositions shown in Table 2 below were prepared in the same manner as in the above Examples.

(Reference example)
As a reference example, a polishing liquid composition having the composition shown in Table 2 below was prepared in the same manner as in the above Example.

Colloidal silica A: primary particle average particle size 28 nm (manufactured by Dupont)
Colloidal silica B: average particle size of primary particles 18 nm (manufactured by Catalyst Chemical Industries)
Colloidal silica C: primary particle average particle size 9 nm (Nissan Chemical)

(Polishing conditions)
・ Polishing tester: Double-side polishing machine (9B type double-side polishing machine, manufactured by Speed Farm Co., Ltd.)
Polishing pad: Polyurethane pad (thickness 0.9 mm, average pore diameter 30 μm (manufactured by Fujibow))
-Polishing disk rotation speed: 32.5 r / min-Polishing pressure: 100 g / cm ² (setting value)
-Polishing liquid supply amount: 100 mL / min-Polishing time: 4 minutes-Number of loaded substrates: 10

(Substrate to be polished)
As a substrate to be polished, a substrate obtained by rough polishing an aluminum substrate (thickness: 1.25 mm, outer diameter: 95 mm) subjected to Ni-P electroless plating (Ni: 88 to 89%, P: 11 to 12%) is used. It was.

(Nano scratch measurement conditions)
・ Measuring equipment: “MicroMAX VMX-2100CSP” manufactured by VISION PSYTEC
Light source: 2Sλ (250 W) and 3Pλ (250 W) (both 100%)
-Tilt angle: -6 °
・ Magnification: Maximum (Field range: 1/120 of the total area)
・ Observation area: total area (substrate with outer circumference 95mmφ and inner circumference 25mmφ)
・ Iris: notch
・ Evaluation: 4 substrates were selected at random from 10 substrates that were put into the polishing tester, and the number of nanoscratches (both) on both sides of each substrate was measured. ) Was divided by 8 to calculate the number of nanoscratches per substrate surface (lines / surface). Moreover, the evaluation of the nanoscratch described in Table 2 below was performed by relative evaluation with respect to the number of nanoscratches (240 / surface) in the reference example. The nano scratch is a fine scratch on the substrate surface having a depth of 10 nm or more and less than 100 nm, a width of 5 nm or more and less than 500 nm, and a length of 100 μm or more.

(Polishing speed)
The weight of the substrate to be polished before and after polishing was measured, and the difference in weight (substrate weight before polishing−substrate weight after polishing) was determined based on the density of Ni—P (8.4 g / cm ³ ) and the surface area of the substrate (131 .9 cm ² ) and the polishing time (4 minutes) to calculate the double-side polishing amount (polishing rate) of the substrate per unit time. The results are shown in Table 2 below as relative polishing rates when the polishing rate of the polishing composition of the reference example is 1.

  As shown in Table 2, the polishing liquid compositions of Examples 1 to 5 including an additive (gelation inhibitor) that is an organic acid that does not contain a nitrogen atom and has a relationship of ΔV ≦ 1000 for gelation inhibition ability. The number of nano scratches was smaller in the substrate polished with the substrate than in the substrates polished with the polishing composition of Comparative Examples 1-6. Moreover, when grind | polishing using the polishing liquid composition of Examples 1-5, the grinding | polishing rate was quicker than the polishing liquid composition of Comparative Examples 1-6. That is, it can be said that the use of the polishing liquid compositions of Examples 1 to 5 can reduce nano scratches without reducing the polishing rate.

  From the above results, according to the polishing composition of the present invention containing a gelation inhibitor that is an organic acid that does not contain a nitrogen atom, the gelation inhibiting ability shows a relationship of ΔV ≦ 1000, and the polishing rate is reduced. It was found that scratches can be reduced.

  The polishing composition and the substrate manufacturing method of the present invention are useful for manufacturing a memory hard disk.

Claims (6)

A polishing composition for a memory hard disk substrate comprising water, colloidal silica, a gelation inhibitor, and at least one of an inorganic acid and an organic phosphonic acid,
The gelation inhibitor is an organic acid containing no nitrogen atom,
A polishing composition for a memory hard disk substrate, wherein the gelation inhibitory ability of the gelation inhibitor exhibits a relationship of (V2-V1) ≦ 1000.
[V1 represents the viscosity (mPa · s) at 25 ° C. of a solution containing 20 wt% colloidal silica and 0.1 wt% gelation inhibitor and adjusted to pH 1.5 with sulfuric acid, and V2 is The viscosity (mPa · s) at 25 ° C. after leaving the solution at 80 ° C. for 24 hours is shown. ]   The polishing composition for a memory hard disk substrate according to claim 1, wherein the gelation inhibitor is at least one organic acid selected from the group consisting of oxalic acid, maleic acid, fumaric acid and methanesulfonic acid.   The polishing liquid composition for a memory hard disk substrate according to claim 1 or 2, wherein an average particle diameter of primary particles of the colloidal silica is 1 to 50 nm.   The polishing liquid composition for a memory hard disk substrate according to any one of claims 1 to 3, wherein the polishing liquid composition has a pH of 0.1 to 6.5.   The polishing composition for a memory hard disk substrate according to any one of claims 1 to 4, wherein the inorganic acid is sulfuric acid. A method for producing a memory hard disk substrate comprising a step of polishing a substrate using a polishing liquid composition,
The method for producing a memory hard disk substrate, wherein the polishing liquid composition is the polishing liquid composition for a memory hard disk substrate according to any one of claims 1 to 5.