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

A technology of glass substrates and manufacturing methods, which is applied in the direction of grinding machine tools, manufacturing tools, grinding tools, etc., can solve the problems of narrow intervals and increased proportion of glass substrates, and achieve the effect of reducing micro-scar defects

Active Publication Date: 2019-03-12
HOYA CORP
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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, manufacturing method of magnetic disk, and polishing pad
  • Manufacturing method of glass substrate for magnetic disk, manufacturing method of magnetic disk, and polishing pad
  • Manufacturing method of glass substrate for magnetic disk, manufacturing method of magnetic disk, and polishing pad

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0057] A glass substrate for a magnetic disk usually undergoes a rough grinding process (rough grinding process), a shape processing process, a finish grinding process (finish grinding process), an end surface grinding process, and a main surface grinding process (first grinding process, second grinding process, etc.) ), chemical strengthening process, etc. to manufacture.

[0058] In the manufacture of this glass substrate for magnetic disks, first, molten glass is molded into a disk-shaped glass substrate (glass disk) by direct press. In addition, in addition to using such a direct press method, it is also possible to cut the sheet glass produced by the down-draw method or the float method into predetermined sizes, and obtain a glass substrate. Next, the main surface of the molded glass substrate is ground (polished) to improve dimensional accuracy and shape accuracy. In this grinding step, the main surface of the glass substrate is generally ground with hard abrasive grain...

no. 2 approach

[0092] As shown in the above configuration 3, the second embodiment of the present invention is a method of manufacturing a glass substrate for a magnetic disk, the method of manufacturing a glass substrate for a magnetic disk including the following grinding treatment: Supply the polishing liquid that comprises abrasive grain, press-bond the polishing pad that is provided with foamed resin layer simultaneously, the glass substrate surface is ground, as above-mentioned polishing pad, use following polishing pad: from the surface as polishing surface of above-mentioned polishing pad to When a load of 2.5 mN is pressed into the circular portion of a cylindrical indenter with a diameter of 50 μm, the amount of sinking of the above-mentioned polishing pad is measured, and the sinking amount of 12 points is continuously obtained at intervals of 50 μm on the surface of the above-mentioned polishing pad. Among the acquired sinking amounts, when an arithmetic mean is obtained from the ...

Embodiment 1～4、 comparative example 1～3

[0129] 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 A glass substrate for a magnetic disk is produced in a polishing step (first polishing step), (6) a chemical strengthening step, and (7) a main surface polishing step (second polishing step).

[0130] (1) Rough polishing process

[0131] First, a diameter of A disk-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.

[0132]Next, the glass substrate is subjected to a polishing process to improve dimensional accuracy and shape accuracy. This polishing step is performed using a double-side polishing device.

[0133]...

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Abstract

The present invention provides a method of manufacturing a glass substrate for a magnetic disk capable of reducing minute waviness in a shape wavelength range of 50 μm to 150 μm. In the present invention, the following polishing pad is used for the polishing process. For this polishing pad, when the surface of the polishing pad is pressed into the circular part of a cylindrical indenter with a diameter of 50 μm with a load of 2.5 mN, the surface of the polishing pad Continuously measure the sinking amount of the polishing pad at 12 points at intervals of 50 μm, and obtain the standard deviation from the data of the sinking amount at 10 points except the maximum value and the minimum value among the obtained sinking amounts, and the standard deviation is 0.15 μm the following.

Description

technical field [0001] This invention relates to the manufacturing method of 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). 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 hi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B5/84B24B37/005B24B37/11C03C19/00
CPCG11B5/8404C03C21/002B24B37/042
Inventor 俵义浩
Owner HOYA CORP
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