JP2005008875A - Abrasive composition and abrasion method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an abrasive composition for a magnetic disk base, capable of decreasing roughness of a surface of the magnetic disk base, without forming protrusions, nor abrasion marks, and capable of realizing recording with high density, without causing adhered residual matter on the surface, and further capable of abrading the base at an economical speed. <P>SOLUTION: The abrasive composition contains water, abrasive grains, an abrasion accelerator, and a surface cleaning agent, wherein the surface cleaning agent comprises at least one kind of compound having two or more hydroxy groups on its 2-6C main chain which may contain oxygen (such as glycerol, ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polishing composition used for precision polishing finishing of metal, plastic, glass and the like, and more particularly, a polishing composition suitable for polishing a magnetic disk substrate used in a storage device such as a computer. More particularly, the present invention relates to a polishing composition such as a magnetic disk substrate that can provide a magnetic disk surface with high polishing accuracy suitable for a magnetic head to fly with a low flying height.

  Magnetic disks (memory hard disks) are widely used as a means for high-speed access in external storage devices of computers and word processors. A typical example of this magnetic disk is a substrate obtained by electrolessly plating NiP on the surface of an Al alloy substrate. After polishing the surface of the substrate, a Cr alloy underlayer, a Co alloy magnetic layer, and a carbon protective layer are sequentially formed. It is formed with a sputter.

  However, if a protrusion having a height higher than the flying height of the magnetic head remains on the surface of the magnetic disk, the magnetic head flying at a high speed while flying at a predetermined height may collide with the protrusion and be damaged. Also, if there are protrusions or polishing scratches on the magnetic disk substrate, when a Cr alloy underlayer film or Co alloy magnetic film is formed, protrusions appear on the surface of those films, and defects based on the polishing scratches occur, resulting in magnetic disk Since the surface does not become a highly accurate smooth surface, it is necessary to polish the substrate precisely in order to increase the accuracy of the disk surface.

  Also, as one of the causes of the above-mentioned protrusion generation, there are cases where abrasive grains and chemicals remain attached on the NiP surface whose surface activity has been strengthened by polishing with a chemical used as a polishing accelerator. If particles of submicron or nanometer size are attached, it will be difficult to remove them only with normal external force. For this reason, a surface cleaner as an anti-adhesion measure is necessary and effective.

  For this reason, many polishing compositions have been proposed in which the protrusions are eliminated or the height thereof is made as low as possible and polishing scratches hardly occur in polishing of the magnetic disk substrate.

  Among them, Patent Document 1 discloses the use of a composition obtained by adding aluminum nitrate and an antigelling agent to colloidal silica, and Patent Document 2 discloses a composition obtained by adding aluminum nitrate to fumed silica. Use is disclosed. Since the compositions disclosed in these publications use silicon oxide fine particles having low hardness for the abrasive grains, it is easy to obtain surface accuracy, but it is difficult to achieve a higher polishing rate in actual production.

  Furthermore, Patent Document 3 proposes the use of many oxidizing agents and the use of Fe salts as means for increasing the polishing rate. However, this was also insufficient to obtain a higher polishing rate in actual production.

  Patent Document 4 discloses polyoxyethylene alkyl ether phosphoric acid and polyoxyethylene allyl ether phosphoric acid as means for eliminating surface residues. However, these compounds are high in polymer and expensive, but have little cleaning effect.

JP-A-9-204657 JP-A-9-204658 Japanese Patent Laid-Open No. 10-204416 JP 2001-89749 A JP 2001-131535 A

  The quality required for an aluminum magnetic disk substrate polishing composition that enables high-density magnetic recording is to achieve a high-precision disk surface that enables low head flying.

  Therefore, an object of the present invention is to achieve high-density recording with a small surface roughness of the magnetic disk substrate, no protrusions or polishing flaws, no surface residue, and economical speed. It is an object of the present invention to provide a polishing composition for a magnetic disk substrate that can be polished by the above method.

  The polishing composition of the present invention that has solved the above problems is a compound having a polyvalent hydroxyl group in a main chain having 2 to 6 carbon atoms that may contain water, polishing abrasive grains, a polishing accelerator, and oxygen. It has a gist where it contains a surface cleaner.

(1) characterized in that it contains water, polishing abrasives, a polishing accelerator, and a surface cleaner that is a compound having a polyvalent hydroxyl group in a main chain having 2 to 6 carbon atoms which may contain oxygen. Polishing composition.
(2) The polishing composition according to (1), wherein the surface cleaner is at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol.
(3) Polishing composition as described in said (1) or (2) whose content rate which occupies for whole polishing composition of surface detergent is 0.1-15 mass%.
(4) The polishing composition according to any one of (1) to (3), wherein the abrasive grains are at least one selected from the group consisting of alumina, titania, silica, and zirconia.
(5) The polishing composition according to any one of (1) to (4), wherein the average particle diameter of the polishing abrasive grains is in the range of 0.001 to 0.5 μm.
(6) The polishing composition according to any one of (1) to (5), wherein the abrasive grains are colloidal particles.
(7) The polishing accelerator is at least one selected from the group consisting of an inorganic acid containing phosphorus or a salt thereof, an inorganic acid not containing phosphorus or a salt thereof, an organic phosphonic acid chelating compound, and an oxidizing agent. The polishing composition according to any one of (1) to (6) above.
(8) As a polishing accelerator, (i) an inorganic acid or a salt thereof containing phosphorus, and (ii) an inorganic acid or a salt thereof not containing phosphorus, and / or an organic phosphonic acid chelating compound, and ( iii) The polishing composition according to any one of the above (1) to (7), comprising an oxidizing agent.
(9) The polishing composition according to (7) or (8), wherein the inorganic acid containing phosphorus is phosphoric acid or phosphonic acid.
(10) The polishing composition according to any one of (7) to (9), wherein the inorganic acid containing no phosphorus is at least one selected from the group consisting of nitric acid, sulfuric acid, amidosulfuric acid, and boric acid. object.
(11) The polishing composition according to any one of (7) to (10), wherein the oxidizing agent is a peroxide or a nitrate.
(12) The polishing composition according to (11), wherein the peroxide is at least one selected from the group consisting of hydrogen peroxide, perborate and persulfate.
(13) The polishing composition according to any one of (1) to (12), wherein the pH is 1 to 5.
(14) The polishing composition according to any one of (7) to (13), wherein the content of the abrasive is in the range of 3 to 30% by mass.
(15) The polishing composition according to any one of (7) to (14), wherein the content of the inorganic acid or a salt thereof is in the range of 0.1 to 8% by mass.
(16) The polishing composition according to any one of the above (7) to (15), wherein the content of the organic phosphonic acid chelating compound is in the range of 0.01 to 10% by mass.
(17) The polishing composition according to any one of (7) to (16), wherein the content of the oxidizing agent is in the range of 0.2 to 5% by mass.
(18) The content of the abrasive is in the range of 3 to 30% by mass, the content of the inorganic acid or its salt is in the range of 0.1 to 8% by mass, and the organic phosphonic acid chelating compound The content is within a range of 0.01 to 10% by mass, and the content of the oxidizing agent is within a range of 0.2 to 5% by mass according to any one of the above (7) to (13). Polishing composition.
(19) The polishing composition according to any one of (1) to (18), further comprising a surfactant.
(20) The polishing composition according to any one of (1) to (19), further comprising a rust inhibitor.
(21) The polishing composition according to any one of (1) to (20), further comprising a preservative.
(22) The polishing composition according to any one of (1) to (21), further comprising an anti-gelling agent.
(23) A polishing kit according to any one of the above (1) to (22), which is a kit of two kinds of compositions, wherein the compositions are mixed, or mixed and diluted. A kit as a composition.
(24) The kit according to (23), wherein one composition is a slurry containing abrasive grains and water, and one composition is a solution containing an inorganic acid, an oxidizing agent, and a surface cleaning agent.
(25) The kit according to (23) or (24), which is for transportation or storage.
(26) A composition that is diluted to become the polishing composition according to any one of (1) to (22) above.
(27) A method of using the composition according to any one of (23) to (26) as a composition for transportation or storage.
(28) A polishing method for polishing a magnetic disk substrate using the polishing composition according to any one of (1) to (26) above.
(29) A method for producing a polishing composition, comprising mixing the two compositions of the kit according to any one of (23) to (25) to obtain a polishing composition.
(30) A polishing method comprising mixing the two compositions of the kit according to any one of (23) to (25) above and polishing using the resulting polishing composition.
(31) A composition is prepared at a component concentration higher than the concentration at the time of polishing, and the concentration is diluted to obtain the polishing composition according to any one of (1) to (22) above, which is used for polishing. A polishing method characterized by the above.
(32) A method of manufacturing a magnetic disk substrate using the polishing method according to any one of (28), (30) and (31).
(33) The method for manufacturing a magnetic disk substrate according to (32), wherein the magnetic disk substrate has a recording density of ³ Git / inch ² or more.
(34) The method for manufacturing a magnetic disk substrate according to (32) or (33), wherein the magnetic disk substrate is an aluminum substrate.
(35) The method for manufacturing a magnetic disk substrate according to (34), wherein the magnetic disk substrate is an aluminum substrate plated with NiP.

When a disk is polished using the polishing composition of the present invention, the surface roughness is very small, the surface can be polished with high surface quality without protrusions and surface adhesion, and at a high speed. A magnetic disk using a polished disk is useful as a low flying type hard disk, and high density recording is possible. In particular, it is highly useful as a high recording density medium (having a recording density of 3 Gbit / inch ² or more) typified by an MR head medium using a magnetoresistive effect of a magnetic disk using a polished disk. The media is also useful from the viewpoint that there is a highly reliable medium.

  The surface cleaner used in the polishing composition of the present invention is a hydrocarbon which may contain oxygen in a main chain having 2 to 6 carbon atoms having a polyvalent hydroxyl group, that is, 2 to 6 carbon atoms which may contain oxygen. A compound having a polyvalent hydroxyl group in the main chain. The effect of this surface cleaning agent includes prevention of adhesion of abrasive abrasive grains and chemical residues that cannot be removed by post-cleaning after adhering to the magnetic disk substrate and cleaning removal. The mechanism is not always clear, but like alcohol, etc., polyvalent hydroxyl groups improve wettability to abrasive grains, chemicals and substrate surface, and have a great effect on adhesion prevention and peeling, resulting in high-quality polishing. It is thought that it plays a big role in forming the surface. However, alcoholic drugs with a simple structure have poor water wettability and are easy to evaporate and scatter, while polymer systems with a large number of carbon atoms are difficult to dissolve in water. Suitable drugs are considered suitable as detergents.

  Specific examples of such surface cleaners include glycerin, ethylene glycol (EG: abbreviation in Table 2), diethylene glycol (DEG: abbreviation in Table 2), triethylene glycol, and propylene glycol.

  The content of the surface cleaning agent in the entire polishing composition is preferably 0.1 to 15% by mass (hereinafter, unless otherwise specified,% is mass%), more preferably 0.5 to 10%. What is preferably 1 to 5% is a preferred embodiment of the present invention.

  The abrasive grains contained in the polishing composition of the present invention as an abrasive are not particularly limited, and for example, alumina, titania, silica, zirconia and the like can be used. Moreover, it is not limited to those crystal forms. For example, alumina (aluminum oxide) includes α-type, γ-type, δ-type, η-type, θ-type, κ-type, χ-type, etc., and titania (titanium oxide) includes rutile-type and anatase-type crystal types. Type, blue kite type, etc., silica (silicon oxide) includes colloidal silica, fumed silica, white carbon, etc., zirconia (zirconium oxide) includes monoclinic, tetragonal, amorphous, etc. Yes, both can be used preferably. It is more preferable that these abrasive grains are colloidal particles because the effect of suppressing generation of micro scratches is large.

  The average particle diameter of the abrasive grains is usually in the range of 0.001 to 0.5 μm, preferably in the range of 0.01 to 0.2 μm, more preferably in the range of 0.02 to 0.2 μm, most preferably 0. In the range of 0.03 to 0.2 μm, colloidal particles are more preferable as described above. Here, the average particle diameter is a value measured by a laser Doppler frequency analysis type particle size distribution analyzer, Microtrac UPA150 (manufactured by Honeywell).

  When the particle size of the abrasive grains is increased, gelation and agglomeration due to fine particles are easily suppressed, but the existence probability of coarse particles is also increased, which is likely to cause polishing flaws. Further, when the particle diameter is reduced, the above-mentioned gelation and aggregation are likely to occur, and in this case as well, it may cause polishing scratches.

  When the abrasive grain concentration in the polishing composition is less than 3%, it is difficult to increase the polishing rate. Further, the polishing rate increases as the concentration increases. However, when the concentration exceeds 30%, the increase in the polishing rate decreases, and in particular, colloidal particles are easily gelled. Considering economical efficiency, 30% or less is preferable for practical use. Therefore, the concentration of the abrasive grains in the composition is preferably in the range of 3 to 30%, more preferably 5 to 15%.

  As a polishing accelerator, an inorganic acid containing phosphorus or a salt thereof, an inorganic acid not containing phosphorus or a salt thereof (also referred to as “other inorganic acid or a salt thereof”), an organic phosphonic acid chelating compound, and / or It is preferable to mix an oxidizing agent.

  In the polishing composition of the present invention, an inorganic acid containing phosphorus or a salt thereof and another inorganic acid or a salt thereof can be used in combination. The inorganic acid containing phosphorus is one containing phosphorus as a constituent element of the compound and is preferably phosphoric acid or phosphonic acid. The inorganic acid containing phosphorus includes its derivatives. Two or more inorganic acids containing phosphorus may be used in combination.

  Nitric acid, hydrochloric acid, sulfuric acid, chromic acid, carbonic acid, amidosulfuric acid, boric acid and the like can be used as the other inorganic acid used together with the inorganic acid containing phosphorus, but nitric acid, sulfuric acid, amidosulfuric acid and boric acid are preferable. . These acids include cases where they are derivatives thereof.

  Examples of salts of inorganic acids containing phosphorus and other inorganic acids include Li, Be, Na, Mg, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Zr, A salt containing a metal such as Nb, Mo, Pd, Ag, Hf, Ta, or W can be used. These salts can be obtained, for example, by dissolving the metal oxide or carbonate in an inorganic acid containing phosphorus and other inorganic acids.

  The total amount of the inorganic acid containing phosphorus or a salt thereof and other inorganic acid or a salt thereof in the polishing composition is 0.1 to 8%, preferably 0.2, based on the polishing composition. The range of -6%, more preferably 0.4-4% is preferable. When the blending amount of the inorganic acid or its salt is less than 0.1%, the effect of suppressing the micro scratch and increasing the polishing rate is small. Further, if it exceeds 8%, the pH may be greatly lowered, so that the polishing equipment needs to have acid resistance. The mixing ratio of the inorganic acid or its salt containing phosphorus and the other inorganic acid or its salt is preferably in the range of 0.1 to 5 mol with respect to 1 mol of the former. If the latter is less than 0.1 mol, the dispersibility of the slurry may be deteriorated, and the microscratch tends to increase. On the other hand, when the amount exceeds 5 moles, the pH is lowered and the damage to the polishing equipment is increased.

  The polishing composition of the present invention contains one or more specific inorganic acids or salts thereof. By using an inorganic acid or salt thereof containing phosphorus as a component, the polishing rate is increased and the effect of suppressing the generation of micro scratches is enhanced. .

  In the present invention, the mechanism of the effect of using one or more specific inorganic acids or salts thereof is not clear, but one is presumed to be because the dispersion state as a polishing composition is improved.

  As one of the polishing accelerators, an organic phosphonic acid chelating compound (for example, Patent Document 5) can be used.

  Specific examples of organic phosphonic acid-based chelating compounds include, for example, diethylenetriaminepentamethylenephosphonic acid, phosphonobutanetricarboxylic acid (PBTC: abbreviation in Table 2), phosphonohydroxyacetic acid, hydroxyethyldimethylphosphonic acid, aminotrismethylene. Examples include phosphonic acid (NTMP: abbreviation in Table 2), hydroxyethane diphosphonic acid (HEDP: abbreviation in Table 2), ethylenediaminetetramethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, and salts thereof.

  The content of the organic phosphonic acid-based chelating compound in the entire polishing composition is preferably in the range of 0.01 to 10%. If it is too small, the polishing rate improvement effect is small, and if it is too large, surface defects such as pits and protrusions are present. And colloidal particles are easily gelled. More preferably, it is 0.05 to 5%.

  The organic phosphonic acid-based chelating compound can be used alone, but can be used in combination with other polishing accelerators for the purpose of further improving the polishing rate.

  The oxidizing agent that can be contained in the polishing composition of the present invention is preferably a peroxide or nitrate. As typical examples, hydrogen peroxide, perborate (for example, sodium perborate), persulfate (for example, ammonium persulfate), and nitrate (for example, ammonium nitrate) are preferable as the peroxide. Examples of the effect of the oxidizing agent include an increase in polishing rate and a decrease in surface roughness. Although the mechanism is not clear, an effect as an etchant on the Ni-P surface is considered.

  In addition, when the said other inorganic acid or its salt has an oxidizing action, it can also be used as an oxidizing agent. For example, nitrates are used as salts of other acids and as oxidizing agents. Of course, even when another inorganic acid or a salt thereof has an oxidizing action, another oxidizing agent may be added.

  The blending amount of the oxidizing agent (for example, hydrogen peroxide) is 0.2 to 5%, preferably 0.5 to 2%. If the blending amount of the oxidizing agent is less than 0.2%, the effect of increasing the polishing rate and decreasing the surface roughness is small, and if it exceeds 5%, the effect becomes saturated.

  When other inorganic acids or salts thereof can also be used as the oxidizing agent, the preferred blending amount is the sum of both blending amounts, that is, the preferred blending amount of other inorganic acid or salt (0.1 to 0.1). 8%) and a preferable blending amount (0.2 to 5%) of the oxidizing agent. Accordingly, in this case, the total amount of phosphorus-containing inorganic acid or salt thereof and other inorganic acid or salt thereof is preferably 0.3 to 13%, more preferably 0.7 to 8%.

  Furthermore, when the above composition contains an inorganic acid or salt thereof that does not become an oxidizing agent and an oxidizing agent (not an inorganic acid or salt thereof), the amount of the inorganic acid or salt that can be used as an oxidizing agent is determined. Thus, the upper limit of the amount of the remaining oxidizing agent (not the inorganic acid or its salt) can be determined. For example, in the case of a combination of phosphoric acid, nitrate (which is a salt of other inorganic acids and an oxidizing agent) and hydrogen peroxide, the compounding amount is determined with all nitrates as salts of other inorganic acids, and hydrogen peroxide is an oxidizing agent. The upper limit can be made 5%. For example, when an inorganic acid that is not an oxidizing agent or a salt thereof is included in the nitrate, the amount of the remaining inorganic acid that is not an oxidizing agent or a salt thereof can be determined by including the nitrate as an oxidizing agent with a limit of 5%. In any case, the total amount of the inorganic acid or salt thereof containing phosphorus, the other inorganic acid or salt thereof, and the oxidizing agent is preferably 0.3 to 13%, more preferably 0.7 to 8%.

  In the polishing composition of the present invention, the pH range is preferably 1 to 5, more preferably 1 to 4, and still more preferably 1 to 3. By making the liquid property acidic, the oxidation of Ni can be promoted and the polishing rate can be improved. However, if the pH is too low, there is a problem such as corrosion of the apparatus, so the pH is 1 to 3, and further 1-2. It is more preferable that

  The polishing composition of the present invention may contain a surfactant, a rust inhibitor, a preservative and the like in addition to the above components. However, it is necessary to pay close attention to the type and amount of addition so as not to cause gelation.

In order to suppress gelation, an antigelling agent may be added to the polishing composition of the present invention. The antigelling agent used is preferably at least one selected from phosphonic acid compounds, phenanthroline and acetylacetone aluminum salt. Specifically, as the phosphonic acid compound, 1-hydroxyethane-1,1-diphosphonic acid (C ₂ H ₆ O ₇ P ₂ ) or aminotrimethylene phosphonic acid (C ₂ H ₁₂ O ₉ P ₃ N) is used. Can be illustrated. Examples of phenanthroline include 1,10-phenanthroline monohydrate (C1 ₂ H ₈ N ₂ .H ₂ O), and examples of acetylacetone aluminum salt include aluminum complex salt of acetylacetone (AlCH (COCH ₃ ) ₃ ]). be able to. These are preferably added within 2%.

  The above-mentioned component concentrations are concentrations when the magnetic disk substrate is polished. When a polishing composition is produced, transported, stored, etc., it is efficient to make the composition thicker than the above concentration and dilute it to the above concentration before use.

  The polishing composition of the present invention, like the conventional polishing composition, suspends the abrasive in water, and adds, for example, an inorganic acid such as phosphoric acid and nitric acid, an oxidizing agent, and a surface cleaner. Can be prepared. In use, a mixture of all components may be diluted and used. For example, the components may be divided into two types according to the components so that stability during transportation or storage is advantageous. If necessary, after transportation and storage, a method of mixing these two types of compositions immediately before use may be employed. For example, it is preferable to divide into a slurry and a solution, specifically, water and abrasive grains, and water, an inorganic acid, an oxidizing agent, and a surface cleaning agent.

The polishing composition of the present invention is advantageous for high recording density substrates (typically having a recording density of 3 Gbit / inch ² or more) typified by a magnetic disk for a magnetic head using the magnetoresistive (MR) effect, for example. However, it can be effectively applied to a magnetic disk having a recording density lower than that from the viewpoint of improving reliability.

  The magnetic hard disk substrate to which the polishing composition of the present invention is applied is not particularly limited, but the composition of the present invention is applied to an aluminum substrate (including an alloy), particularly an aluminum substrate plated with NiP, for example, electrolessly. Then, a high-quality polished surface can be advantageously obtained industrially.

  The polishing method is a method in which a polishing pad generally used for a slurry-like abrasive is slid onto a magnetic disk substrate, and the pad or the substrate is rotated while supplying the slurry between the pad and the substrate.

  The magnetic disk produced from the substrate polished with the polishing composition of the present invention has a very low frequency of occurrence of minute defects such as micropits and microscratches, and the surface roughness (Ra) is 3 mm or less. Excellent smoothness.

Hereinafter, examples of the present invention will be specifically described. However, the present invention is not limited to these examples, and all modifications may be made without departing from the spirit of the preceding and following descriptions. Included in the technical scope.
Table 1 shows the abrasives used in Examples and Comparative Examples and their characteristics.

(Examples 1-5)
Colloidal silica (Cyton HT-50) manufactured by DuPont Co., Ltd., water, inorganic acid 1 (inorganic acid containing phosphorus or salt thereof), inorganic acid 2 (other inorganic acid or salt thereof: hereinafter the same) And / or organic phosphonic acid-based chelating compounds, oxidizing agents, and surface cleaners in the proportions shown in Table 2 to prepare various aqueous polishing compositions, and with the polishing apparatus and polishing conditions shown below. Polishing was performed. The results are shown in Table 2.

(Examples 6 and 7)
White silica (E-150J) manufactured by Nippon Silica Kogyo Co., Ltd. or fumed silica (AEROSIL-50) manufactured by Nippon Aerosil Co., Ltd. is pulverized with a medium stirring mill, coarse particles are removed by sizing, and the average particle size First, 0.1 μm of silicon oxide was obtained. Next, water, an inorganic acid 1, an inorganic acid 2, an oxidizing agent, and a surface cleaner are added in the proportions shown in Table 2 to prepare various aqueous polishing compositions, which are polished with the polishing apparatus and polishing conditions shown below. Went. The results are shown in Table 2.

(Examples 8 to 10)
Titanium oxide (Super Titania F-4), alumina, and zirconia manufactured by Showa Titanium Co., Ltd. are pulverized by a medium stirring mill, coarse particles are removed by sizing, and titanium oxide, alumina, and zirconia having an average particle diameter of 0.2 μm. I got first. Next, water, an inorganic acid 1, an inorganic acid 2 or an organic phosphonic acid chelating compound, an oxidizing agent, and a surface cleaner are added in the proportions shown in Table 2, and various aqueous polishing compositions are prepared. Polishing was performed with the polishing apparatus and polishing conditions shown. The results are shown in Table 2.

  The average particle diameter was measured with a laser Doppler frequency analysis type particle size distribution analyzer, Microtrac UPA150 (manufactured by Honeywell). The measured particle size is shown in Table 1. The pH of the composition was measured with a D-13 glass electrode type hydrogen ion concentration meter manufactured by Horiba, Ltd.

(Polishing conditions)
As the substrate, a 3.5-inch size aluminum disk on which NiP was electrolessly plated was used.

(Polishing equipment and polishing conditions)
Polishing tester 4-way double-side polishing machine Polishing pad Suede type (Polytex DG, made by Rodel)
Lower surface plate rotation speed 60rpm
Slurry supply rate 50 ml / min Polishing time 5 minutes Processing pressure 4.9 kPa (50 g / cm ² )
(Evaluation of polishing characteristics)
Polishing rate: converted from weight loss before and after polishing of aluminum disk Surface roughness: Taristep, Taridata 2000 (manufactured by Rank Taylor Hobson) is used

  Depth of polishing scratch: The shape was analyzed by the three-dimensional mode of a stylus type surface analyzer P-12 (manufactured by TENCOR) to determine the depth.

  Table 2 shows the evaluation results of the polishing characteristics. The polishing flaw A in Table 2 has a polishing flaw depth of 2 nm or less. The polishing flaw B has a polishing flaw depth of 2 to 10 nm. No polishing flaw depth greater than 10 nm occurred in both the examples and the comparative examples.

  Surface cleanliness (bright spot): Nikon Differential Interference Microscope Dark field mode x50 magnification, observe the upper and lower surfaces of a single abrasive disc in a cross, and shine points (bright spots, abrasives, polishing debris, chemicals, etc.) Counted). The total number of bright spots of 20 or less was designated as rank A, and the above as rank B.

(Comparative Examples 1-3, 5-6)
Water, inorganic acid 1, inorganic acid 2 and / or organic phosphonic acid-based chelating compound, and oxidizing agent are added to DuPont's colloidal silica (Cytton HT-50) in the proportions shown in Table 2 for aqueous polishing. A composition was prepared and polished as in the examples. The results are shown in Table 3.

(Comparative Example 4)
Water, aluminum nitrate, and hydrogen peroxide were added to DuPont's colloidal silica (Cyton HT-50) in the proportions shown in Table 2 to prepare an aqueous polishing composition, which was polished in the same manner as in the examples. The results are shown in Table 3.

(Comparative Example 7)
White carbon (E-150J) manufactured by Nippon Silica Kogyo Co., Ltd. was pulverized with a medium stirring mill and coarse particles were removed by sizing to obtain silicon oxide having an average particle size of 0.1 μm. Next, water, inorganic acid 1, inorganic acid 2, and oxidizing agent were added in the proportions shown in Table 2 to prepare various aqueous polishing compositions, which were polished in the same manner as in the examples. The results are shown in Table 3.

(Comparative Example 8)
Titanium oxide (Super Titania F-4) manufactured by Showa Titanium Co., Ltd. was pulverized with a medium stirring mill and coarse particles were removed by sizing to obtain titanium oxide having an average particle diameter of 0.2 μm. Next, water and aluminum nitrate were added in the proportions shown in Table 2 to prepare an aqueous polishing composition, which was polished in the same manner as in the examples. The results are shown in Table 3.

(Comparative Examples 9 and 10)
Alumina and zirconia were pulverized by a medium stirring mill and coarse particles were removed by sizing to obtain alumina and zirconia having an average particle diameter of 0.2 μm. Next, water, an inorganic acid 1, an inorganic acid 2 or an organic phosphonic acid-based chelating compound, and an oxidizing agent are added in the proportions shown in Table 2, and various aqueous polishing compositions are prepared. did. The results are shown in Table 3.

Claims (35)

  For polishing comprising water, polishing abrasives, polishing accelerator, and a surface cleaner that is a compound having a polyvalent hydroxyl group in a main chain of 2 to 6 carbon atoms which may contain oxygen Composition.   The polishing composition according to claim 1), wherein the surface cleaner is at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol.   The polishing composition according to claim 1 or 2), wherein the content of the surface cleaner in the entire polishing composition is 0.1 to 15% by mass.   The polishing composition according to any one of claims 1 to 3, wherein the abrasive grains are at least one selected from the group consisting of alumina, titania, silica and zirconia.   The polishing composition according to any one of claims 1 to 4, wherein the average particle size of the abrasive grains is in the range of 0.001 to 0.5 µm.   The polishing composition according to any one of claims 1 to 5, wherein the abrasive grains are colloidal particles.   2. The polishing accelerator is at least one selected from the group consisting of an inorganic acid containing phosphorus or a salt thereof, an inorganic acid not containing phosphorus or a salt thereof, an organic phosphonic acid chelating compound, and an oxidizing agent. The polishing composition as described in any one of -6.   As a polishing accelerator, (i) an inorganic acid or a salt thereof containing phosphorus, and (ii) an inorganic acid or a salt thereof not containing phosphorus, and / or an organic phosphonic acid chelating compound, and (iii) an oxidation Polishing composition of any one of Claims 1-7 containing an agent.   The polishing composition according to claim 7 or 8, wherein the inorganic acid containing phosphorus is phosphoric acid or phosphonic acid.   The polishing composition according to any one of claims 7 to 9, wherein the inorganic acid not containing phosphorus is at least one selected from the group consisting of nitric acid, sulfuric acid, amidosulfuric acid, and boric acid.   The polishing composition according to any one of claims 7 to 10, wherein the oxidizing agent is a peroxide or a nitrate.   The polishing composition according to claim 11), wherein the peroxide is at least one selected from the group consisting of hydrogen peroxide, perborate and persulfate.   pH is 1-5, Polishing composition of any one of Claims 1-12.   The polishing composition according to any one of claims 7 to 13, wherein the content of the abrasive is in the range of 3 to 30% by mass.   The polishing composition according to any one of claims 7 to 14, wherein the content of the inorganic acid or a salt thereof is in the range of 0.1 to 8% by mass.   The polishing composition according to any one of claims 7 to 15, wherein the content of the organic phosphonic acid chelating compound is in the range of 0.01 to 10% by mass.   The polishing composition according to any one of claims 7 to 16, wherein the content of the oxidizing agent is in the range of 0.2 to 5 mass%.   The content of the abrasive is in the range of 3 to 30% by mass, the content of the inorganic acid or its salt is in the range of 0.1 to 8% by mass, and the content of the organic phosphonic acid chelating compound is The polishing composition according to any one of claims 7 to 13, wherein the polishing composition is in the range of 0.01 to 10 mass%, and the content of the oxidizing agent is in the range of 0.2 to 5 mass%.   The polishing composition according to any one of claims 1 to 18, further comprising a surfactant.   Furthermore, the polishing composition of any one of Claims 1-19 containing a rust preventive agent.   Furthermore, the polishing composition of any one of Claims 1-20 containing a preservative.   Furthermore, the polishing composition of any one of Claims 1-21 containing an antigelling agent.   It is a kit of 2 types of compositions, Comprising: Those kits which become the polishing composition of any one of Claims 1-22 by mixing or diluting and mixing those compositions.   24. The kit according to claim 23, wherein one composition is a slurry containing abrasive grains and water, and one composition is a solution containing an inorganic acid, an oxidizing agent, and a surface cleaning agent.   The kit according to claim 23 or 24, wherein the kit is for transportation or storage.   A composition that is diluted to become the polishing composition according to any one of claims 1 to 22.   The method of using the composition of any one of Claims 23-26 as a composition for transport or storage.   A polishing method for polishing a magnetic disk substrate using the polishing composition according to claim 1.   A method for producing a polishing composition, comprising mixing the two compositions of the kit according to any one of claims 23 to 25 to obtain a polishing composition.   A polishing method comprising mixing two compositions of the kit according to any one of claims 23 to 25 and polishing using the resulting polishing composition.   23. A polishing method comprising preparing a composition at a component concentration higher than the concentration at the time of polishing, diluting the concentration to obtain the polishing composition according to claim 1, and using the composition for polishing .   32. A method of manufacturing a magnetic disk substrate using the polishing method according to any one of claims 28, 30, and 31. The method of manufacturing a magnetic disk substrate according to claim 32, wherein the magnetic disk substrate has a recording density of ³ Git / inch ² or more.   34. The method of manufacturing a magnetic disk substrate according to claim 32 or 33, wherein the magnetic disk substrate is an aluminum substrate.   The method of manufacturing a magnetic disk substrate according to claim 34, wherein the magnetic disk substrate is an aluminum substrate plated with NiP.