JPH01227224A - Target for producing sputtered magnetic disk medium and production of sputtered magnetic disk medium - Google Patents

Abstract

PURPOSE:To obtain the medium having magnetic anisotropy by forming plural V-grooves concentrically to a disk-shaped surface thereby projecting and depositing sputtered particles onto a disk substrate diagonally therefrom. CONSTITUTION:The plural V-grooves 13 are formed on the surface of a disk- shaped target 11 concentrically around the center 12 of said disk. The V-grooves 13 are logically calculated and designed in the angle of inclination of slops 14 which grade downward toward the center of the disk in such a manner that the film of the sputtered particles can be formed at a desired film thickness distribution in the radial direction when the sputtered particles are deposited on a substrate 1 for the disk. The sputtered particles 16 jump out at a reflection angle 30 deg. and deposit on the surface of the substrate 1 when incident argon ions 15 are projected to the slopes 14 of 30 deg. grading angle at 30 deg. incident angle therewith.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a target used for manufacturing a sputter magnetic disk medium, which is a metal thin film magnetic recording medium with excellent high-density recording characteristics, and a method for manufacturing a sputter magnetic disk medium. It is related to.

BACKGROUND OF THE INVENTION In order to obtain good high-density recording characteristics, it is necessary to make the recording medium thinner, have a higher coercive force, and have a higher residual magnetic flux density ratio.

A CO-based alloy magnetic thin film is attracting attention as a magnetic material that satisfies this condition. Further, as a method for manufacturing the medium, a sputtering method is suitable because it allows easy formation of an alloy thin film. Recently, by using in-line continuous sputtering equipment, it has become possible to sputter a non-magnetic base film, a magnetic film, a protective film, and a solid lubricant film continuously in this order on a non-magnetic substrate. Mass production of media became possible. The magnetic disks thus obtained are put into practical use as hard disk drives.

Incidentally, the mainstream magnetic film for sputtered magnetic disk media is one in which a Co-Ni film is formed on a Cr underlayer, or one in which a Co-Ni-Cr film is formed on a Cr underlayer.
In addition, there are those that use Cr as the base layer and sputter a Co-Pt alloy on top of it, those that use W as the base layer and sputter Co-Pt on top of it, and those that use Cr as the base layer and sputter Co-Pt on top of it. Sputtered Co-Cr,
There is a method in which Bi is used as an underlayer and Co--Ni is sputtered thereon, and these are currently in the process of being put into practical use.

In addition, in the method of manufacturing sputtered thin films, there are static sputtering equipment in which the magnetic disk substrate is stationary during sputtering, and mobile sputtering equipment in which the magnetic disk substrate is moving. A sputtering target whose surface is processed to be flat is used.

In an in-line stationary sputtering apparatus, a disk-shaped sputtering target is generally used when manufacturing a sputtered magnetic disk medium. FIG. 5 shows the inside of the apparatus when manufacturing a sputter magnetic disk medium using this disk-shaped target. In the figure, reference numeral 2 denotes a disc-shaped target, which is sputtered by an annular magnetron sputtering method, and the sputtered particles 5 flying out from the erosion region 4 sputter onto the magnetic disk substrate 1. Note that 3 is a permanent magnet formed in an annular shape.

Problems to be Solved by the Invention By the way, since the surface of the above-mentioned target is flat, sputtered particles that are repelled by particles (for example, Ar particles) that collide with the target almost perpendicularly also fly out almost perpendicularly from the surface of the target. Therefore, the light is also incident almost perpendicularly to the magnetic disk substrate 1 and is deposited. If the base Cr film and the Co--Ni alloy magnetic film are sputtered in such a state, no magnetic anisotropy occurs in the medium plane, and the magnetostatic characteristics and electromagnetic conversion characteristics are unfavorable. In addition, it is generally well known that in order to generate magnetic anisotropy in the plane of the medium, it is better to apply sputtered particles to the magnetic disk substrate 1 by obliquely injecting them. In the sputtering apparatus shown in FIG. 5, it is not easy to perform oblique incidence deposition, and the apparatus needs to be significantly improved.

Means for Solving the Problems In order to solve the above problems, the present invention forms a plurality of V-shaped grooves concentrically on the surface of a target.

Effect With the above configuration, even if particles fall almost perpendicularly to this target, they will hit the oblique side of the V-shaped groove obliquely.
Therefore, sputtered particles fly out diagonally from the target. Therefore, the sputtered particles are incident and deposited on the magnetic disk substrate obliquely, resulting in a medium having magnetic anisotropy. Furthermore, since the V-shaped grooves are provided concentrically, the sputtered particles deposited on the magnetic disk substrate have an easy magnetization axis in the circumferential direction of the magnetic disk substrate, and a difficult magnetization axis in the radial direction.

Example An embodiment of the present invention will be described below.

FIG. 1 is a diagram showing a sputtering magnetic disk target according to an embodiment of the present invention, and FIG.
b) The figure shows a cross-sectional view.

As shown in the figure, a disk-shaped target 11
A plurality of V-shaped grooves 13 are formed concentrically around the center 12 of the disc on the surface of the disc. In addition, as shown in FIG. 3(b), the plurality of ■-shaped grooves are formed so that the vertical cross-sectional shape of the target is serrated. As shown in the enlarged view of FIG. 2, this V-shaped groove slopes downward toward the center of the disk. The film thickness distribution is theoretically calculated and determined so that a desired thickness can be formed in the radial direction. For example, as shown in FIG. 2, when the incident argon ions 15 are incident at an incident angle of 30' to the inclined surface 14 with a gradient angle of 30'', the sputtered particles 16 fly out at a reflection angle of 30'', and the sputtered particles 16 are ejected from the magnetic disk substrate 1. Deposits on surfaces. Based on this theory, the inclination angle of the V-shaped groove 13 is determined in consideration of the arrangement position of the magnetic disk substrate 1 and the position of the erosion area 17 of the target. Incidentally, an inclined surface adjacent to the inclined surface 14,
That is, if the slope angle of the slope 18 that slopes downward toward the outside of the target is set to 45 degrees or more, the sputtered particles 16 flying out from the slope 18 will fall onto the magnetic disk substrate 1.
There is no problem of equivalence because it will be deposited on the target again.

Furthermore, FIG. 3 shows a layout diagram when manufacturing a sputter magnetic disk medium using the target having V-shaped grooves of the present invention. Then, as shown in the figure, when sputtering is performed with the magnetic disk substrate 1 facing the V-shaped groove forming surface of the target, sputtered particles fly out from the inclined surface 14 of the V-shaped groove of the target. is incident obliquely in the radial direction of the magnetic disk substrate l and is deposited.
Further, the light is applied at right angles to the circumferential direction of the magnetic disk substrate 1. Therefore, in the magnetic thin film formed on the surface of the magnetic disk substrate 1, the axis of easy magnetization is in the circumferential direction and the axis of difficult magnetization is in the radial direction, resulting in in-plane magnetic anisotropy.

Here, sputtering is performed on a magnetic disk substrate using the target shown in Figure 1 and a conventional target (a target with a flat surface), and the resulting magnetic disk medium is measured using a vibrating sample magnetometer (V, S .

M) The magnetostatic characteristics measured using the device are shown in Table 1, and the electromagnetic conversion characteristics are shown in FIG.

As the substrate for the magnetic disk, an aluminum substrate with N1-P plating on the surface was used, and a 3000A Cr underlayer, a 50A magnetic film under the name of Conat*-N 1aat, and a Cr protective film were applied to this. loo in, C solid lubricant film 3oO, argon gas pressure 5m t o r r
, Continuous sputtering was performed at a substrate temperature of 150° C. using an in-line static sputtering device.

From Table 1 above, when sputtering is performed using the target of this example, the squareness ratio S in the circumferential direction and the coercive force He become large, and the squareness ratio S and the coercive force He in the radial direction become small (become This shows that the circumferential direction is the axis of easy magnetization and the radial direction is the axis of hard magnetization, resulting in in-plane magnetic anisotropy.In contrast, when using conventional targets, It can be seen that the magnetic disk obtained by sputtering using this method has the same coercive force He and squareness ratio S in both the circumferential direction and the radial direction, and no in-plane anisotropy occurs.

Furthermore, as can be seen from the characteristic curve diagram shown in FIG. 4, the reproduction output of the magnetic disk obtained using the target of this example is 20% lower than that of the magnetic disk obtained using the conventional target. It becomes larger, and the recording density is also higher.
The value of D-, which indicates the recording density that produces half the playback output during low-density recording, is also 35.8KFRPI (
Ki l.

Flax Return Per Inch).

Further, although a Co-based alloy was used as the magnetic film in the above embodiment, a magnetic disk having in-plane anisotropy can be provided using an Fe-based alloy as in the above embodiment.

Effects of the Invention In the present invention, by forming a plurality of V-shaped grooves concentrically on the surface of the target, even if particles fall almost perpendicularly to the target, they will not hit the inclined surfaces of the V-shaped grooves obliquely. Therefore, the sputtered particles fly out from the target obliquely, and as a result, the sputtered particles are incident and deposited on the magnetic disk substrate obliquely, resulting in a medium having magnetic anisotropy. Moreover, since the V-shaped grooves are provided concentrically, the sputtered particles deposited on the magnetic disk substrate have an easy magnetization axis in the circumferential direction of the magnetic disk substrate, and a difficult magnetization axis in the radial direction. It is possible to provide a sputtered magnetic disk medium with excellent magnetostatic characteristics, which is very effective in practice.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view of a target for manufacturing a sputter magnetic disk medium according to an embodiment of the present invention, FIG. 1(b) is a sectional view thereof, and FIG. 2 is an enlarged view of the main part of FIG. 1(b). , FIG. 3 is a side view showing the inside of the sputtering apparatus when sputtering a magnetic disk substrate using the target of this example, and FIG. A characteristic curve diagram showing the electromagnetic conversion characteristics of a magnetic disk and a magnetic disk obtained by sputtering using a conventional target. Figure 5 shows the inside of the sputtering device when sputtering onto a magnetic disk substrate using a conventional target. FIG. DESCRIPTION OF SYMBOLS 1... Magnetic disk substrate, 2... Target, 3... Permanent magnet, 4... Erosion area, 5... Sputtered particles , 11・
...Target, 12... Center of the disk,
13... V-shaped groove, 14... Inclined surface,
15... Argon ion, 16... Sputtered particles, 17... Erosion area, 18...
Inclined surface, name of agent Patent attorney Toshio Nakao and one other person Figure 1 Figure 2 Figure 5

Claims (4)

[Claims] (1) A target for producing a sputter magnetic disk medium, which has a disk-like outer shape and has a plurality of concentric V-shaped grooves formed on its surface. (2) The target for manufacturing a sputter magnetic disk medium according to claim 1, wherein a plurality of V-shaped grooves are formed so that the vertical cross-sectional shape is sawtooth. (3) In the V-shaped groove, the slope angle of the slope toward the center of the target is greater than 45 degrees, and the slope angle of the slope toward the outside of the target is 45 degrees or less. A target for manufacturing a sputter magnetic disk medium according to scope 2. (4) Using the target for producing a sputtered magnetic disk medium according to claim 1, placing a magnetic disk substrate opposite to the surface of the target on which the V-shaped groove is formed, and A method of manufacturing a sputtered magnetic disk medium, comprising performing sputtering on a disk substrate.