Method of Manufacturing Silicon Substrates for Magnetic Recording Medium, Silicon Substrate for Magnetic Recording Medium, Magnetic Recording Medium, and Magnetic Recording Apparatus

Abstract

A manufacturing method for silicon substrates for a magnetic recording medium has the steps of forming a stack body of a number of silicon substrates which are stacked via spacers therebetween, wherein each silicon substrate has a circular hole at a center of the substrate; immersing the stack body of the silicon substrates in a polishing liquid in which grains are suspended; and polishing inner peripheral end faces of the circular holes of the silicon substrates, wherein in polishing, a polishing brush contacts the end faces while performing a relative rotation between the end faces and the polishing brush, and the stack body of the silicon substrates is inverted during polishing. The step of polishing the inner peripheral end faces may be performed before inner and outer peripheries of the silicon substrate are subjected to chamfering. Preferably, the polishing brush is made of polyamide resin.

Description

[0001] Priority is claimed on Japanese Patent Application No. 2004-237340, filed Aug. 17, 2004, and U.S. Provisional Patent Application No. 60 / 603,566, filed Aug. 24, 2004, the contents of which are incorporated herein by reference.TECHNICAL FIELD [0002] The present invention relates to a silicon substrate for a small-sized magnetic recording medium, which is used as a recording medium for a data processing apparatus. BACKGROUND ART [0003] Accompanying recent progress in data processing apparatuses, data recording capacity of a magnetic recording medium has increased more and more. In particular, in magnetic disks, which are important media as external memory for computers, both storage capacity and data recording density increase every year, and development for recording data with higher density is required. For example, in accordance with development of notebook computers or palmtop computers, small-sized and impact-resistant magnetic recording media are required, and therefore sm...

AI Technical Summary

Benefits of technology

[0021] In view of the above circumstances, an object of the present invention is to improve the accuracy and reduce dimensional variation of the inner diameters of the center circular holes of the silicon substrates, to efficiently manufacture silicon substrates suitable for hard disk drives which have consistent quality and can be rotated at high speed, and to provide a magnetic recording apparatus in which a magnetic recording medium using such silicon substrates is mounted.

[0033] According to the present invention, the accuracy in dimensions in center circular holes of silicon substrates is strictly regulated. Therefore, it is possible to easily mass-produce hard disk drives which have consistent quality and can be rotated at high speed.

Problems solved by technology

However, a substrate which has been subjected to NiP plating tends to be warped, and may be magnetized when being processed at a high temperature.

In addition, when the glass substrate is processed so as to be strengthened, a distortion layer may be produced in a surface of the substrate and the substrate may receive compressive stress, and the glass substrate also tends to be warped when being processed at a high temperature.

Regarding an ultra-small-sized magnetic recording medium having a diameter of 1 inch (i.e., 25.4 mm) or 0.85 inches (i.e., 21.6 mm) which requires higher recording density, warp of the substrate is a fatal problem.

The material for the silicon substrate is fragile; thus, cracks or chips tend to be produced in the above manufacturing processes.

When cracks or chips are produced, the yield rate for manufacturing the magnetic recording medium is reduced, and generated particles may cause errors in a write / read process, or a crash of the magnetic head in the write / read process.

Therefore, the accuracy for processing the center circular hole is important, and if this accuracy is inadequate, a problem may occur in assembling of a hard disk drive which can be rotated at high speed.

The silicon substrate is fragile; thus, a hard disk drive having high accuracy cannot be obtained by only limiting the surface roughness of the finished inner peripheral end face as shown in Reference 3.

With inadequate accuracy in dimensions of the inner diameters, it is impossible to mass-produce hard disk drives having consistent quality and high performance.

However, no trial or attempt for regulating the accuracy relating to the dimensional variation of the inner diameters of the center circular holes has been implemented.

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