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Polishing composition for hard disk substrate

A technology of composition and polishing liquid, which is applied in the direction of polishing composition containing abrasive, grinding device, grinding machine, etc., and can solve the problems of reducing the surface roughness and micro ripples of the hard disk substrate surface

Inactive Publication Date: 2014-03-19
KAO CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in order to cope with the low float of the magnetic head, it is necessary to reduce the surface roughness and micro waviness of the hard disk substrate surface.

Method used

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  • Polishing composition for hard disk substrate
  • Polishing composition for hard disk substrate
  • Polishing composition for hard disk substrate

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Experimental program
Comparison scheme
Effect test

preparation example Construction

[0078] [Preparation Method of Polishing Liquid Composition]

[0079] The preparation method of the polishing liquid composition of the present invention is not limited in any way, for example, it can be prepared by mixing alumina particles, silica particles, an acid or its salt, and an oxidizing agent in an appropriate aqueous medium. The above-mentioned dispersion of alumina particles and silica particles can be performed using a mixer such as a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill. The content or concentration of each component in the polishing liquid composition of the present invention is within the above-mentioned range, but as another form, the polishing liquid composition of the present invention can also be prepared in the form of a concentrate.

[0080] [Manufacturing method of hard disk substrate]

[0081] Another aspect of the present invention relates to a method of manufacturing a hard disk substrate. As the first embodiment of ...

Embodiment

[0099] Embodiments of the present invention are further illustrated below by way of examples. The following examples are for the purpose of illustrating the present invention only and should not be construed as limiting the present invention.

[0100] 1. Preparation of grinding liquid composition

[0101] α-alumina (volume median diameter of secondary particles: 0.3 μm or 0.6 μm), θ-alumina (volume median diameter of secondary particles: 0.16 μm), colloidal silica, maleic acid , citric acid, sulfuric acid (98% product), hydrogen peroxide (35% by weight product, manufactured by Asahi Denka Corporation) and water, according to the composition shown in Table 1, prepare the grinding liquid of Examples 1~33 and Comparative Examples 1~14 combination. In addition, copolymers synthesized from monomers shown in Table 4 below were added to the polishing liquid compositions of Examples 21 to 26. The solubility in Table 4 below is the solubility (g) in 100 g of water at 20°C.

[0102]...

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Abstract

A polishing composition for a hard disk substrate includes alumina particles, silica particles, and water. The volume median diameter of secondary particles of the alumina particles measured by a laser beam diffraction method is 0.1 to 0.8 m. The volume median diameter of primary particles of the silica particles measured by transmission electron microscope observation is 40 to 150 nm. The standard deviation in number-basis particle size of the primary particles of the silica particles measured by the transmission electron microscope observation is 11 to 35 nm. The polishing composition for a hard disk substrate can preferably reduce the embedding of alumina abrasive grains into the substrate without impairing the productivity.

Description

technical field [0001] The present invention relates to a polishing liquid composition for a hard disk substrate, a polishing method using the polishing liquid composition, and a method for producing a hard disk substrate. Background technique [0002] With the rapid spread of computers, the start of digital broadcasting, etc., high capacity and miniaturization of hard disk drives are required. For example, as a method of increasing the recording density of a storage hard disk used in a hard disk drive, a technical solution of reducing the floating amount of the magnetic head and reducing the unit recording area has been proposed. However, in order to cope with the low float of the magnetic head, it is necessary to reduce the surface roughness and fine waviness of the hard disk substrate surface. In order to meet this requirement, there are known abrasive slurries that can improve the surface properties of polished substrates (JP-A-2005-186269, JP-A-2006-518549, and JP-A-20...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K3/14C09G1/02B24B37/02G11B5/84
Inventor 铃木真彦末永宪一铃木诚
Owner KAO CORP