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Manufacturing method of glass substrate for information recording medium, and manufacturing method of magnetic disk

A glass substrate and information recording technology, which is applied in the direction of manufacturing tools, manufacturing base layers, and record carrier manufacturing, to achieve the effects of preventing surface roughness, reducing cerium oxide residues, and suppressing surface roughness

Inactive Publication Date: 2016-03-02
ASAHI GLASS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

One is the problem of mechanical properties such as vibration characteristics and strength during high-speed rotation, and the other is the problem of removing foreign matter remaining on the glass substrate

Method used

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

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0126] 30 of the above-mentioned pre-cleaned glass discs were spin-dried. Spin-drying was performed by putting 30 glass discs in a Ultem (registered trademark) resin box and rotating the box at room temperature (approximately 23° C.) at an ambient temperature of 1000 rpm for 1 minute.

[0127] The spin-dried 30 glass disks were immersed in an aqueous solution having a sulfuric acid concentration of 71.4% by mass, a hydrogen peroxide concentration of 7.7% by mass, and a temperature of 80° C. for 10 minutes to clean. Example 1 is an embodiment.

[0128] With respect to the 30 glass discs A thus obtained, the occurrence frequency (%) of surface roughness was measured in the following manner.

[0129] Using Opti-flat manufactured by ADE, the surface shape of both sides of the glass disc was observed by the white interferometry, and the glass disc having pits with a size of 1 mm×1 mm or more was used as a glass plate with surface roughness. The value obtained by dividing the numb...

example 2

[0133] For comparison, the remaining 20 glass discs after the above-mentioned pre-cleaning were kept in a state where water was attached to the glass surface without drying, and the concentration of sulfuric acid was 71.4% by mass, the concentration of hydrogen peroxide was 7.7% by mass, and the temperature was Washing was performed by immersing in an aqueous solution at 80° C. for 5 minutes. Example 2 is a comparative example.

[0134] The occurrence frequency (%) of surface roughness was measured for 20 glass discs B obtained in this way, and the result was 100%.

[0135] It should be noted, figure 2 This is an example of a glass disk having a rough surface. figure 2 Among the parts observed as linear blackening, that is, one in the upper right, one in the lower part whose length is almost the same as that in the upper right, and one in which the length is twice as long are surface rough parts.

[0136] In addition, in the same manner as the examination of glass disk A,...

Embodiment 2

[0139] Using the following nine kinds of aqueous solutions as the first cleaning liquid, the above-mentioned pre-cleaned glass disks were immersed in the first cleaning liquid for 5 minutes each to clean them. Then, the following aqueous solution A was used as a second cleaning solution, and the mixture was immersed in the second cleaning solution heated to 80° C. for 5 minutes to perform cleaning (Examples 3 to 11). Examples 3-7 are examples, and Examples 8-11 are comparative examples.

[0140] Furthermore, for comparison, the glass disk was cleaned using the aqueous solution A heated to 80° C. as the second cleaning solution without using the first cleaning solution (Example 12).

[0141] As the first cleaning solution, nine kinds of aqueous solutions in which the inorganic acid was sulfuric acid or nitric acid, and the concentration (unit: mass %) of the inorganic acid and the temperature (unit: °C) of the cleaning solution were shown in Table 1 were used.

[0142] In addi...

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Abstract

Disclosed is a process for producing a glass substrate for information recording media through a polishing step in which a glass disk is polished using a slurry containing abrasive grains of cerium oxide. In the process, the abrasive grains of cerium oxide are inhibited from remaining and the main surface is inhibited from becoming rough. The process for producing a glass substrate for information recording media includes a lapping step in which a glass disk is lapped and a cerium oxide polishing step in which the glass disk is subsequently polished with abrasive grains of cerium oxide. The process further includes: subsequently to the cerium oxide polishing step, either a drying step (a) in which the glass disk is dried or a cleaning step (b) in which the glass disk is cleansed with a first cleaning fluid that contains one or more inorganic acids selected from a group consisting of sulfuric acid and nitric acid in a concentration of 55 mass% or higher and that has a temperature of 30ºC or lower; and a cleaning step (c) in which the glass disk after the step (a) or (b) is cleansed with a second cleaning fluid having a sulfuric acid concentration of 55-80 mass%, a hydrogen peroxide concentration of 1-10 mass%, and a temperature of 70ºC or higher.

Description

technical field [0001] This invention relates to the manufacturing method of the glass substrate for information recording media, and the manufacturing method of a magnetic disk, and relates to the cleaning process at the time of manufacturing a glass substrate especially. Background technique [0002] In recent years, there have been two technical issues related to the glass substrate in the trend of high-capacity magnetic disks. One is a problem of mechanical properties such as vibration characteristics and strength during high-speed rotation, and the other is a problem of removing foreign matter remaining on the glass substrate. [0003] In order to improve the vibration characteristics and strength during high-speed rotation, it is necessary to use a glass substrate with an appropriate glass composition in consideration of various characteristics such as Young's modulus, specific modulus, specific gravity, thermal expansion coefficient, scratch resistance, and fracture t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11B5/84C03C23/00
CPCG11B5/8404B24B37/044C03C19/00C03C23/0075C09G1/02C09K3/1409C09K3/1463
Inventor 三代均田村昌彦帕里查·提帕阳宫谷克明
Owner ASAHI GLASS CO LTD
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