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Manufacturing method of glass substrate for magnetic disk, glass substrate for magnetic disk, and manufacturing method of magnetic disk

A technology for glass substrates and manufacturing methods, which is applied in the manufacture of base layers, disc carrier manufacturing, magnetic recording layers, etc., which can solve the problems of increased proportion of glass substrates, narrow intervals, etc., and achieve the effect of reducing foreign matter defects

Active Publication Date: 2018-10-23
HOYA CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, recently, with the demand for high-density recording, glass substrates can narrow the distance between the magnetic head and magnetic disk compared with aluminum substrates, so the proportion of glass substrates has gradually increased.

Method used

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  • Manufacturing method of glass substrate for magnetic disk, glass substrate for magnetic disk, and manufacturing method of magnetic disk
  • Manufacturing method of glass substrate for magnetic disk, glass substrate for magnetic disk, and manufacturing method of magnetic disk
  • Manufacturing method of glass substrate for magnetic disk, glass substrate for magnetic disk, and manufacturing method of magnetic disk

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0134] After the following (1) rough grinding process (rough grinding process), (2) shape processing process, (3) finish grinding process (finish grinding process), (4) end surface grinding process, (5) main surface Polishing process (1st grinding|polishing process), (6) chemical strengthening process, (7) main surface grinding|polishing process (2nd grinding|polishing process), the glass substrate for magnetic discs of this Example was manufactured.

[0135] (1) Rough polishing process

[0136] First, a diameter of , A disc-shaped glass substrate made of aluminosilicate glass with a thickness of 1.0 mm. Moreover, in addition to obtaining a glass substrate by such direct press, it is also possible to obtain a glass substrate by cutting sheet glass produced by a down-draw method or a float method into a predetermined size.

[0137] Next, the glass substrate is subjected to a polishing process to improve dimensional accuracy and shape accuracy. This polishing step is perform...

Embodiment 2

[0155] As said colloidal silica, except having used what content of Al was 3 microgram / g, it carried out similarly to Example 1, and obtained the glass substrate for magnetic discs. In addition, the Al content is the content of Al contained in the solid substance obtained by evaporating and drying the colloidal silica slurry.

Embodiment 3

[0157] As said colloidal silica, except having used what content of Al was 5 microgram / g, it carried out similarly to Example 1, and obtained the glass substrate for magnetic discs.

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Abstract

Provided is a magnetic disk glass substrate manufacturing method capable of reducing foreign body defects that can cause head crashes even when using a HDI sensor. The present invention includes a polishing treatment wherein the surface of a glass substrate is brought into contact with a polishing pad and a polishing liquid containing a colloidal silica and the surface of the glass substrate surface is polished to a mirror polish. A polishing liquid that does not contain foreign bodies containing the elements of Al, Si, and O, which can interfere with recording and playback when recording or playing back using a magnetic head and a magnetic disk made of the glass substrate, is selected as the polishing liquid, and the polishing treatment is performed using this polishing liquid.

Description

technical field [0001] This invention relates to the glass substrate for magnetic discs used for the magnetic disc mounted in the magnetic recording apparatuses, such as a hard disk drive (it abbreviates to "HDD" hereafter), and its manufacturing method. Background technique [0002] Magnetic disks exist as one type of information recording media mounted on magnetic recording devices such as HDDs. A magnetic disk is formed by forming a thin film such as a magnetic layer on a substrate, and an aluminum substrate has conventionally been used as the substrate. However, recently, with the demand for higher recording density, glass substrates can narrow the distance between the magnetic head and the magnetic disk compared with aluminum substrates, so the proportion of glass substrates has gradually increased. In addition, the surface of the glass substrate is polished with high precision to reduce the levitation height of the magnetic head as much as possible, thereby realizing ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B5/84G11B5/73
CPCG11B5/8404
Inventor 越阪部基延德光秀造山城祐治竹内亮太郎
Owner HOYA CORP