JPH0680532B2 - Method of manufacturing thin film magnetic disk - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film magnetic disk used in a magnetic recording device which is one of peripheral devices such as a computer.

2. Description of the Related Art In recent years, a magnetic recording device has been remarkably developed as a peripheral device of a computer, and further miniaturization and higher density recording have been advanced. Most of the magnetic disks used for this purpose are those of γ-iron oxide coating type, but at the present time, there is a tendency toward thinning in order to achieve higher density recording. In order to make the coating type thinner, especially in the case of a hard disk, a method such as spin coating or a method such as coating and polishing to thin the film is used. In addition to the coating type, vacuum technology, for example, sputtered film formation Using technology, cobalt-
Metallic films such as Teckel element, cobalt-chromium, and oxide films such as γ-iron oxide and barium ferrite are widely used. Cobalt-chromium and barium ferrite have recently been studied extensively as a medium having a higher density than that of an in-plane magnetic film as a perpendicular magnetic film.

An in-plane magnetized film containing cobalt as a main component has also been studied by a thin film forming technique, and if it can be made thinner, it is more promising as a higher density medium than a coating type medium.

When this medium is applied to a hard disk, it is vacuum-deposited on the surface of a disk with high smoothness, such as a disk for a hard disk made of an aluminum-magnesium alloy or a glass disk
It is applied by a thin film forming technology such as sputter deposition and is being studied for practical use. In the case of a flexible disk,
It is being studied to deposit it on an organic film such as polyethylene terephthalate, polyamide, or polyimide by the above-mentioned thin film forming method.

Problems to be Solved by the Invention Media such as hard disks and flexible disks are
It is used by rotating it in the in-plane direction around the center of the disk, and recording / reproducing is performed in the circumferential direction. In this case, if the magnetization directions of the medium are aligned in the circumferential direction,
The magnetization reversal during recording becomes smoother, the output during reproduction becomes large, and the noise level also decreases. Regarding the coating film, before the coating film solidifies, a medium is placed in a rotating magnetic field so that the magnetization direction is aligned in the circumferential direction (for example, JP-B-53-62505). However, even when the above-mentioned disk is produced by using a thin film forming technique such as vacuum evaporation or sputter evaporation, it is necessary to form the film by magnetizing so as to have an easy axis of magnetization in the circumferential direction.

Means for solving the problems When forming a magnetic film by vacuum vapor deposition, sputter vapor deposition, etc.,
It is known that when a magnetic field is applied in a certain direction during film formation, an easy axis of the film can be formed in that direction and a hard axis can be formed in a direction at right angles. This phenomenon becomes easier with soft magnetic films,
Easy axis and difficult axis can be created without external magnetic field.

However, a magnetic film with a large coercive force used as a magnetic recording medium is difficult to produce the above anisotropy unless a magnetic field is applied from the outside, and especially when it is desired to align it in the circumferential direction such as a disk. That's right. Therefore, in the present invention, in view of the above point, (i) if the substrate is a disk, it is rotated about its center as an axis and is deposited through a slit that is long in the radial direction. At this time, a DC magnetic field is applied in the vicinity of the slit in the direction perpendicular to the radial direction in the substrate surface with a permanent magnet.

(Ii) When the substrate is tape-shaped and a circular film is formed on the tape-shaped substrate, a slit is provided on the rotary disc, and the slit is rotated so that the longitudinal direction of the slit is the radial direction. At this time, a DC magnetic field is applied by a permanent magnet at right angles to the longitudinal direction of the slit.

In this way, the magnetization direction is aligned in the circumferential direction by always forming the film so that the easy axis direction of the film is perpendicular to the radial direction of the disk.

Working The operation of this technical means is as follows.

When a disk with in-plane magnetization composed of a metal magnetic film is formed by the means of the present invention, the easy axis of magnetization of the magnetic film is always perpendicular to the radial direction of the disk disc, that is, in the circumferential direction. It is the same as the case where the needle-shaped γ-iron oxide is aligned in the circumferential direction with the γ-iron oxide coating type. Therefore, the magnetization reversal at the time of recording and reproduction becomes easy, and the output and noise
The output ratio also improves.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples.

(Example 1) Co-Ni-P containing Co as a main component was vapor-deposited by a vacuum vapor deposition technique, and was deposited on a disc-shaped substrate through a slit having a width of 5 mm and a length of 90 mm. At this time, the center of the slit was made to be the center of the substrate on which the film was deposited, and the substrate was rotated in the plane. The rotation speed was 15 seconds per rotation. In the width direction of the slit, permanent magnets are provided at the positions shown in FIG.
It's a pole. The polarities of the permanent magnets provided in the slits are symmetrical with respect to the center of rotation, so that they are always the same in the direction of rotation. Although the magnetization direction is disturbed in the central portion, the substrate in this portion is mechanically punched and removed, so that it is unnecessary. Reference numeral 1 is a motor for rotating a substrate, 2 is a transmission shaft thereof, 3 is a substrate, 4 is a shutter provided with a slit 9, 8 and 8'are permanent magnets provided on both sides of the slit, and in this embodiment, 500. An Oersted Alnico magnet was used. 5 is a pillar of the shutter 4 with a slit 9, 6 is an evaporation source of Co-Ni-P, and 7 is a vacuum chamber.

By this method, the above magnetic film having a thickness of 1000 angstrom was formed. Discs with a diameter of 10 mm were punched out from several places on the disc, and the torque curves in the radial direction of the disc and the circumferential direction perpendicular thereto were measured. As a result, the circumferential direction was always the easy axis direction.

(Example 2) Parallel plate magnetron sputtering was used, and a shutter having a slit and a permanent magnet having basically the same configuration as in Example 1 was installed in front of the substrate. In this example, the substrate was rotated, but the shutter was used. There is no problem even if the substrate is fixed by rotating it so that it is coaxial with the substrate axis. FIG. 2 shows an embodiment of the present invention. Ten
Is a motor for rotating the substrate, 11 is a transmission shaft of the substrate, 12 is a substrate holder, 13 is a substrate, 14 is a shutter with a slit and a permanent magnet, 15 is a pillar of the shutter, 16 is a target of Co-Ni-P, 17 Is a magnet for sputtering.

The rotation of the substrate was set to 15 seconds / rotation, 350 Watt, a target size of φ90 mm, a film was formed by RF sputtering in an argon pressure of 5 × 10 ^-2 Torr, and the thickness was set to 1000 Å. As a result of examining torque curves in several radial and circumferential directions of the substrate in the same manner as in Example 1, the circumferential direction was the easy axis direction as in Example 1.

EFFECTS OF THE INVENTION As described above, according to the method of the present invention, a magnetic disk having an easy axis in the circumferential direction can be formed by a film forming technique such as vacuum evaporation or sputter evaporation. It is very useful for obtaining a high density magnetic recording medium because it is easy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an embodiment of a manufacturing method of the present invention by a vacuum vapor deposition method, and FIG. 2 is a diagram showing an embodiment similarly using a sputter vapor deposition method. 3 ... substrate, 4 ... slit, shutter with permanent magnet,
8,8 '... Permanent magnet, 9 ... Slit, 12 ... Substrate, 14
…… Slits, shutters with permanent magnets, 16 …… targets, 17 …… sputter magnets.

Claims (2)

[Claims] 1. A method of manufacturing a thin film magnetic disk in which an axis of easy magnetization is provided in a circumferential direction on the surface of a disk-shaped substrate by vacuum vapor deposition or sputtering, the method comprising: Form a slit-shaped gap in the radial direction,
Moreover, a mask provided with fixed permanent magnets so that one side of the slit in the width direction has the S pole and the other side has the N pole is placed on the evaporation source side in parallel and close to the disk-shaped substrate, A method of manufacturing a thin-film magnetic disk, comprising forming a magnetic thin film while rotating the substrate about its center. 2. The permanent magnets fixed on both sides of the slit-like gap have a magnetizing force of sufficient strength to magnetize the magnetic thin film deposited on the disk-shaped substrate. A method of manufacturing a thin film magnetic disk according to the item.