JP2002020732A - Polishing composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing composition capable of making a high-quality polished surface having no surface defect while keeping high polishing rate, more specifically, to provide a polishing composition capable of making a smooth and excellent polished surface having no surface defect with good polishing efficiency in polishing a substrate surface plated with Ni-P for an aluminum magnetic disk. SOLUTION: This polishing composition is obtained by including at least water, alumina and a solution product of an aluminum salt and, more preferably, is characterized by including in addition, a polishing accelerator in the above components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing composition, and more particularly to a polishing composition for a magnetic disk substrate incorporated in a hard disk drive of a computer.

[0002]

2. Description of the Related Art Hitherto, in polishing a substrate for a magnetic disk, many polishing compositions have been proposed as a polishing composition which has a high polishing rate and hardly causes defects such as scratches, pits, projections and polishing scratches on the surface. . For example, JP-A-61-
Japanese Patent No. 291674 includes a polishing composition containing sulfamic acid or phosphoric acid, Japanese Patent Application Laid-Open No. 62-25187 includes aluminum nitrate, and Japanese Patent Application Laid-Open No. 2-158682 includes a metal compound containing nitrite. It has been disclosed.

Japanese Patent Application Laid-Open No. Hei 4-27587 discloses a polishing composition comprising aluminum sulfate or aluminum chloride, peroxide, nitric acid, nitrate, nitrite and aromatic nitro compound, each of which is added as a polishing accelerator. Proposed. Further, as a polishing composition effective for obtaining a high-quality polished surface without surface defects with high efficiency, boehmite, a composition obtained by adding a boehmite alumina sol or a colloidal alumina polishing accelerator has been proposed. I have.

For example, JP-A-1-188264 (composition obtained by adding boehmite to alumina), JP-A-1-2055973 (composition obtained by adding metal salt and boehmite to alumina), JP-A-2-84485
JP-A No. 2-15 (Polishing composition comprising gluconic acid, lactic acid and their soda salts and colloidal alumina)
No. 8683 (composition obtained by adding an ammonium salt of boehmite, an inorganic acid or an organic acid to alumina) and JP-A-3-115383 (composition obtained by adding boehmite and a water-soluble peroxide to alumina) JP-A-4-36
No. 3385 (composition obtained by adding a chelate compound, boehmite, and aluminum salt to alumina);
No. 1-92749 (composition comprising a polyamine-based chelate compound or a polyaminocarboxylic acid-based chelate compound on alumina and boehmite) and the like are reported.

[0005] All of these are intended to obtain a high-quality polished surface free of surface defects such as pits, projections, and scratches while maintaining a high polishing rate. However,
In the rapidly evolving field of computer hardware, narrower gaps (flying height) between the magnetic head and the magnetic disk in a hard disk drive can increase the recording density, resulting in higher quality finishing. Surfaced disks are constantly being demanded. However, for such constant practical required performance,
Satisfactory results have not been obtained.

[0006]

As described above, in order to increase the recording density, the flatness and flatness of the disk substrate are good, the surface roughness is small, and pits, projections, scratches and the outer periphery of the disk are required. It is necessary that there is no edge sag occurring at the end. Regarding these characteristics, on a high-quality polished surface which is required to have a surface roughness Ra of about 15 ° or less, even fine pits and projections which have been conventionally accepted may cause a problem. There is a need for an excellent polishing composition that can be used.

[0007] In order to meet these demands, the present invention is to provide a polishing composition which maintains a high polishing rate and produces a high-quality polished surface free from surface defects. More specifically, the present invention provides a polishing composition capable of producing an excellent polished surface having good polishing efficiency and having no surface defects when polishing a substrate surface of an aluminum magnetic disk plated with Ni-P. Is what you do.

[0008]

The present inventor has made the following efforts as a result of diligent efforts. That is, (1) a polishing composition characterized by containing at least water, a sol product of alumina and an aluminum salt, and (2) a polishing composition according to the preceding item 1, further comprising a polishing accelerator. Composition,

(3) The polishing composition according to the above (1), wherein the polishing accelerator is at least one selected from the group consisting of organic acids, inorganic acids and salts thereof, and (4) sol formation of an aluminum salt. Product is aluminum salt and sodium hydroxide, potassium hydroxide, ammonia, organic amine compound,
1 to 3 above, which are sol-formed products obtained by mixing at least one selected from the group consisting of an amine chelate compound, an aminocarboxylic acid, an aminocarboxylic acid chelate compound and an aminophosphonic acid chelate compound. The polishing composition according to any one of the above,

(5) The aluminum salt is an inorganic aluminum salt such as aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum phosphate and aluminum borate; or an aluminum acid salt such as an organic acid aluminum salt such as aluminum acetate, aluminum lactate and aluminum stearate. The polishing composition according to the above item 4, which is at least one of a hydrate or an anhydride of a salt,

(6) The aluminum salt sol product is
Aluminum sulfate, aluminum chloride, at least one aluminum salt selected from the group consisting of aluminum nitrate, and at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia, triethanolamine, aminotrismethylenephosphonic acid The polishing composition according to any one of the above items 1 to 3, which is obtained by mixing one kind of compound,

(7) The content of the polishing accelerator is 0.01 to 1
7. The polishing composition according to any one of the above items 2 to 6, which is 0% by mass, and (8) the polishing composition according to the above items 2 to 7, wherein the content of the aluminum salt sol product is 0.01 to 5% by mass. Any one
Polishing composition according to the paragraph,

(9) Aluminum salt, sodium hydroxide, potassium hydroxide, ammonia, organic amine compound,
A solification product of an aluminum salt, wherein at least one selected from the group consisting of an amine chelate compound, an aminocarboxylic acid, an aminocarboxylic acid chelate compound, and an aminophosphonic acid chelate compound is mixed with a stirrer. How to manufacture the

(10) The method for producing an aluminum salt sol product according to the above item 9, wherein the aluminum salt is at least one selected from the group consisting of aluminum sulfate, aluminum chloride and aluminum nitrate, (11) stirring The method for producing a sol product of an aluminum salt according to the above item 9 or 10, wherein the machine is a high shear stirrer,

(12) While supplying the polishing composition according to any one of the above items 1 to 8 between the original magnetic disk substrate and the polishing pad, the magnetic disk substrate or the polishing pad 13. A method for manufacturing a magnetic disk substrate, the method including: rotating at least one of them. (13) The method for manufacturing a magnetic disk substrate according to item 12, wherein the magnetic disk substrate is an aluminum disk on which Ni-P is electrolessly plated. Provide a way.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polishing composition containing at least a sol product of water, alumina and an aluminum salt, and more preferably to a polishing composition containing a polishing accelerator in the above components. In particular, an aluminum salt sol formed by the reaction of an aluminum salt with an inorganic alkali compound that dissociates into a hydroxyl ion in an aqueous solution or ammonia or an amine compound that hydrates to generate a free hydroxyl group is contained. A polishing composition characterized by the following:

The sol product of the aluminum salt has the effect of increasing the polishing rate in synergy with the polishing accelerator, but also adjusts the viscosity of the whole composition and increases the dispersibility and redispersibility of the alumina particles. effective. Further, there is an effect that the retention of alumina on the polishing pad is improved and the amount of edge sag is reduced.

The alumina used in the present invention is an α type, θ
It is not limited to a crystal form such as a type and a γ type, but α type alumina having a high polishing rate is preferable. The particle size of alumina is not limited, but is preferably in the range of 0.02 to 5 μm in average particle size, and more preferably in the range of 0.3 to 2 μm. In the present invention, the average particle diameter can be appropriately selected depending on the required surface roughness.

In the polishing composition of the present invention, the alumina content is preferably in the range of 1 to 30% by mass, more preferably 3 to 20% by mass. The sol product of the aluminum salt used in the polishing composition of the present invention is an inorganic acid aluminum salt such as aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum phosphate, aluminum borate or aluminum acetate,
Sodium hydroxide, potassium hydroxide, ammonia, an alkyl having 1 to 10 carbon atoms is dissolved in an aqueous solution in which at least one of a hydrate or an anhydride of an aluminum salt such as an organic acid aluminum salt such as aluminum lactate or aluminum stearate is dissolved. Organic amine compounds such as amines (eg, monomethylamine, dimethylamine, trimethylamine, methylethylamine, etc.) and hydroxyalkylamines represented by triethanolamine, (poly)
Amine-based chelate compounds (ethylenediamine, diethylenetriamine, bipyridine), aminocarboxylic acids ( also known as amino acids such as glycine and glutamic acid), and (poly) aminocarboxylic acid-based chelate compounds (eg, ethylenediaminetetraacetic acid EDTA, diethylenepentaacetic acid DTPA, nitrilo) NTA acetate, iminodiacetic acid, etc.),
A sol product obtained by high-shear stirring and mixing at least one selected from the group consisting of aminophosphonic acid-based chelating compounds such as diethylenetriaminepentamethylenephosphonic acid and aminotrismethylenephosphonic acid, , Aluminum salt,
When a substance such as ammonia or an amine which easily reacts with water to generate a hydroxyl group to be liberated or a compound having a hydroxyl group as a terminal group or a compound having a hydroxyl group such as sodium hydroxide or potassium hydroxide is mixed, a chain is formed (when the component compound is To form a chain).

The present inventors have proposed that the sol-formed substance can be analyzed by X-ray diffraction or N-ray diffraction.
When a structural analysis was performed by MR, a specific peak of pseudo-boehmite crystals was observed in a boehmite sol obtained by solubilizing boehmite alumina with gluconic acid or aluminum nitrate, whereas aluminum sulfate, an example of the composition proposed in the present invention, was used. And ammonia, aluminum chloride and ammonia, aluminum sulfate and sodium hydroxide, and any combination of aluminum sulfate and triethanolamine, no specific diffraction peaks such as pseudo-boehmite were observed, and the diffraction pattern was broad. Yes, these were presumed to be amorphous structures.

From this result, although the network structure of the sol-formed product is not always clear, Al atoms are bonded to free hydroxyl groups to form aluminum hydroxide (Al (OH) ₃ ) having a bayerite structure, and further hydrated. It is expected to form amorphous hydrated alumina Al (OH) ₃ .nH ₂ O sol.

The content of the aluminum salt used in the present invention is 0.01% based on the whole composition containing the sol product.
When the amount is less than 0.01% by mass, the effect is not obtained. When the amount is more than 5% by mass, gelation occurs, and surface defects such as pits and projections occur. Occurs.

As the first embodiment of the polishing accelerator used, an organic acid or an inorganic acid salt can be used. As the organic acid, at least one selected from the group consisting of malonic acid, succinic acid, adipic acid, lactic acid, malic acid, citric acid, glycine, aspartic acid, tartaric acid, gluconic acid, pepttogluconic acid, iminodiacetic acid, and fumaric acid The inorganic acid salt can be selected from the group consisting of sodium sulfate, magnesium sulfate, nickel sulfate, aluminum sulfate, ammonium sulfate, nickel nitrate, aluminum nitrate, ammonium nitrate, ferric nitrate, aluminum chloride, and nickel sulfamate. You can choose at least one of them.

The content of the organic acid or the inorganic acid salt is 0.0
It is in the range of 1 to 10% by mass, preferably 0.1 to 2% by mass. If the amount is less than 0.01% by mass, there is no effect as a polishing accelerator, and if the amount is more than 10% by mass, pits and projections are generated, and the quality of the polished surface deteriorates. In addition, undesired effects also occur on the liquid properties, such as the occurrence of aggregation of alumina particles.

Next, as a second embodiment of the polishing accelerator used, an organic acid and an organic acid salt, or an organic acid and an inorganic acid salt can be used in combination. As the organic acid, as described above, malonic acid, succinic acid, adipic acid, lactic acid,
Malic acid, citric acid, glycine, aspartic acid, tartaric acid, gluconic acid, peptogluconic acid, iminodiacetic acid, at least one selected from the group consisting of fumaric acid can be selected, and the organic acid salt is the potassium salt of the organic acid , Sodium salts and ammonium salts.

As the inorganic acid salt, a group consisting of sodium sulfate, magnesium sulfate, nickel sulfate, aluminum sulfate, ammonium sulfate, nickel nitrate, aluminum nitrate, ammonium nitrate, ferric nitrate, aluminum chloride and nickel sulfamate, as described above. You can choose at least one more selected. In any combination of the organic acid and the organic acid salt and / or the inorganic acid salt, the total content is 0.01 to 0.01 with respect to the entire polishing composition.
It is in the range of 10% by mass, preferably 0.1 to 2% by mass, and the content of the organic acid must be at least 0.003% by mass.

In the case of the mixed polishing accelerator, 0.01
When the amount is less than 10% by mass, the effect as a polishing accelerator is poor. When the amount is more than 10% by mass, the viscosity of the abrasive solution becomes too high, and an undesirable influence on the liquid property such as the aggregation of alumina particles occurs. Further, pits and protrusions are generated on the polished surface, which leads to deterioration of quality, which is not preferable. In addition, in the case of a combination of an organic acid and an organic acid, a combination of the same type gives better results in polishing characteristics.

In addition to the above components, the polishing composition of the present invention may further contain, as additives, alumina sol, a surfactant, a detergent, a rust inhibitor, a preservative, a pH adjuster, a thickener, and celluloses or sulfamines. A surface modifier such as an acid or phosphoric acid can be added as needed. The polishing composition of the present invention preferably has a pH of 2 to 6.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below, but the present invention is not limited to these embodiments.

[0030]

EXAMPLES The composition conditions shown in Table 1 were applied to Examples 1 to 16, and the composition conditions shown in Table 2 were applied to Comparative Examples 1 to 10. Below, the preparation method of the abrasive composition, the compounding example of the sol product of aluminum salt,
The polishing conditions for the disk substrate and a method for evaluating the polishing characteristics of the substrate will be described.

(Preparation of Abrasive Composition) After heating aluminum hydroxide in an air atmosphere at about 1200 ° C. in a firing furnace to obtain α-alumina, this was pulverized and wet-classified to obtain an average particle size of 0. 6 μm, 0.7 μm and 1.0 μm alumina samples were produced. Next, separately, for the ratio of aluminum salt to ammonia water or other basic compound, specific compounds shown in Tables 1 and 2 are combined and blended, and these are mixed to form a sol product of the aluminum salt. Manufactured.
However, the composition examples of the sol-formed product are summarized below. Tables 1 and 2 were used as polishing composition samples, respectively.
Was weighed, blended and mixed with water, alumina, an aluminum salt solification product or a polishing accelerator so as to have a component composition of, and provided for a polishing sample.

(Examples of Formulation of Sol-Formed Product of Aluminum Salt) Formulation examples (blending weight ratio) of the sol-formed product of aluminum salt are shown below. Aluminum sulfate / ammonia sol; water: aluminum sulfate (18 hydrate, the same applies hereinafter): 28
% Ammonia water = 20: 5: 3.6 aluminum sulfate / aminotrismethylenephosphonic acid (abbreviated as NTMP) sol; water: aluminum sulfate: NTMP = 20: 5: 15 aluminum sulfate / diethylenetriaminepentamethylenephosphonic acid (DTPMP) Abbreviation) sol; water: aluminum sulfate: DTPMP = 20: 5: 15

Aluminum sulfate triethanolamine (hereinafter abbreviated as TEA) sol; water: aluminum sulfate: TEA = 20: 5: 15 aluminum chloride ammonia sol; water: aluminum chloride (hexahydrate): 28% aqueous ammonia = 20: 5: 3.6 aluminum nitrate / ammonia sol; water: aluminum nitrate (9-hydrate, the same applies hereinafter): 28%
Ammonia water = 20: 5: 3.6

Aluminum nitrate triethanolamine sol; water: aluminum nitrate: TEA = 20: 5: 15 aluminum sulfate / sodium hydroxide sol; water: aluminum sulfate: 50% sodium hydroxide = 2
0: 5: 3 The addition amount (content) of the sol-formed product was calculated and defined as the total weight of the aluminum salt and the compound mixed with the same, excluding the water content.

(Polishing Conditions) The work to be polished is Ni
Using a 3.5-inch aluminum disk electrolessly plated with -P, a polishing test and disk evaluation were performed under the following conditions. Polishing test conditions Polishing test machine: 9B double-side polishing machine (manufactured by System Seiko Co., Ltd.) Polishing pad ゛: Polytex DG Surface plate rotation speed: Upper platen 28 rpm, lower platen 45 rpm, Sun gear 8 rpm Slurry supply amount: 100 ml / min Polishing Time: 5 minutes Processing pressure: 80 g / cm ²

(Evaluation Method of Disk) Polishing rate: Calculated from reduced weight of disk before and after polishing Polishing surface quality: Counting pits, protrusions, and scratches by microscopic observation Pits and protrusions were observed on the front and back of five disks in a cross shape. The number of scratches in the visual field (× 50) Scratch was observed on the front and back of one disk in a cross shape. The number is within the field of view (× 100). Edge sag amount: Measured by surf coder SE-30D (manufactured by Kosaka Laboratories) The edge sag amount is shown in FIG.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

As described above, the polishing composition containing at least a sol product of water, alumina and an aluminum salt, preferably the polishing composition of the present invention further containing a polishing accelerator in the above-mentioned components, It is possible to obtain a high-quality mirror-finished surface with a high speed, a small amount of edge sag, and no surface defects. From the comparison of Table 1 and Table 2, as the effect of adding the sol-formed product of the aluminum salt, the edge sag amount is reduced, a polished surface having good surface properties with few pits, projections and scratches is obtained, and the polishing rate is increased. Effect. Further, in the polishing composition of the present invention, it was found that when a polishing accelerator was also added, the polishing rate was further increased, and accordingly, the edge sag was also improved.

[0040]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for defining an edge sagging amount; In FIG. 1, a perpendicular line h is provided along the outer peripheral edge of a drawing line S obtained by tracing the outer peripheral portion of the polished hard disk surface with a surf coder, and the point of 3000 μm on the drawing line toward the center of the disk with respect to h is A, 2000 μm. When the point is B, a point extending 500 μm from the perpendicular h as an extension of a straight line passing through AB is defined as C, a perpendicular k is provided at the point C, and the perpendicular k
The intersection of the drawing line S and D was D, and the length t between C and D was measured as the edge sag amount.

[0041]

[Explanation of symbols]

S: Draw line near the outer peripheral end of the disk by the surf coder h: Perpendicular line in contact with the outer peripheral end of the disk A: Point located 3000 μm above the perpendicular line h B: Point located 2000 μm above the perpendicular line h C: Point A , 500 μm from the perpendicular h on a straight line passing through point B
K: perpendicular line passing through point C D: intersection of perpendicular line k and drawing line S t: length between point C and point D (edge sag amount)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuro Ukita 153 Maburo, Narumi-cho, Midori-ku, Nagoya-shi, Aichi Prefecture Inside Yamaguchi Seiken Kogyo Co., Ltd. (72) Inventor Kimihiro Hong, Narumi-cho, Midori-ku, Nagoya, Aichi Prefecture 153 Ryogo Yamaguchi Seiken Kogyo Co., Ltd. (72) Inventor Yoshinori Suzuki 153 Murogo, Narumi-cho, Midori-ku, Nagoya-shi, Aichi F-Term in Yamaguchi Seiken Kogyo Co., Ltd. 3C058 AA07 CB01 CB02 CB03 CB10 DA02 5D112 AA02 AA11 AA24 BA01 BA06 EE01 GA02 GA09 GA14

Claims (13)

[Claims] 1. A polishing composition comprising at least a sol product of water, alumina and an aluminum salt. 2. The polishing composition according to claim 1, further comprising a polishing accelerator. 3. The polishing composition according to claim 2, wherein the polishing accelerator is at least one selected from the group consisting of organic acids, inorganic acids, and salts thereof. 4. A sol product of an aluminum salt, wherein the aluminum salt is sodium hydroxide, potassium hydroxide, ammonia, an organic amine compound, an amine chelate compound, an aminocarboxylic acid, an aminocarboxylic acid chelate compound,
The polishing composition according to any one of claims 1 to 3, wherein the polishing composition is a sol product obtained by mixing at least one selected from the group consisting of aminophosphonic acid-based chelate compounds. 5. An aluminum salt such as an inorganic acid aluminum salt such as aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum phosphate and aluminum borate; or an organic acid aluminum salt such as aluminum acetate, aluminum lactate and aluminum stearate. The polishing composition according to claim 4, wherein the polishing composition is at least one of a hydrate and an anhydride. 6. A sol-forming product of an aluminum salt, wherein at least one aluminum salt selected from the group consisting of aluminum sulfate, aluminum chloride, and aluminum nitrate, sodium hydroxide, potassium hydroxide, ammonia,
4. A compound obtained by mixing at least one compound selected from the group consisting of triethanolamine and aminotrismethylenephosphonic acid.
The polishing composition according to any one of the above. 7. The polishing composition according to claim 2, wherein the content of the polishing accelerator is 0.01 to 10% by mass. 8. The polishing composition according to claim 1, wherein the content of the sol product of the aluminum salt is 0.01 to 5% by mass. 9. An aluminum salt and a group consisting of sodium hydroxide, potassium hydroxide, ammonia, an organic amine compound, an amine chelate compound, an aminocarboxylic acid, an aminocarboxylic acid chelate compound and an aminophosphonic acid chelate compound. A method for producing a sol product of an aluminum salt, which comprises mixing at least one selected material with a stirrer. 10. The method according to claim 10, wherein the aluminum salt is aluminum sulfate,
The method for producing a sol product of an aluminum salt according to claim 9, which is at least one selected from the group consisting of aluminum chloride and aluminum nitrate. 11. The stirrer according to claim 9, wherein said stirrer is a high shear stirrer.
Or a method for producing an aluminum salt sol product according to item 10. 12. A method according to claim 1, wherein the polishing composition according to any one of claims 1 to 8 is supplied between an original magnetic disk substrate and a polishing pad. A method for manufacturing a magnetic disk substrate, comprising a step of rotating at least one. 13. The method for manufacturing a magnetic disk substrate according to claim 12, wherein the magnetic disk substrate original plate is an aluminum disk on which Ni--P is electrolessly plated.