JPS63175226A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the corrosion resistance of the title medium by sputtering a target consisting of carbon or silicon oxide or silicon nitride under specified conditions to form a protective layer to be provided on a thin metal film magnetic layer. CONSTITUTION:The target consisting of carbon or silicon oxide or silicon nitride is sputtered under conditions where the product of the distance between the target and the substrate and the pressure of the sputtering gas is controlled to <=5X10<-2>Torr.cm to form the protective layer having <1,000Angstrom film thickness to be provided on the thin metal film magnetic layer consisting of a magnetic metal such as Fe, Co, and Ni or the alloy thereof. A gas consisting essentially of Ar and having high sputtering efficiency is preferably used as the sputtering gas in the industry. The corrosion resistance is improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium, and more particularly to a method for manufacturing a magnetic recording medium in which a protective X1 layer is formed on a thin gold layer.

[Prior Art] In magnetic disk devices used as external storage devices for computers, etc., magnetic recording media having a metal WI film magnetic layer are being used as a means of achieving high recording density.

However, since the metal thin film magnetic layer is easily damaged by mechanical contact with the head and has drawbacks in its corrosion resistance, it is essential to provide a retainer IIm on top of it to compensate for these drawbacks.

The conditions that the protective layer must satisfy are as follows: 1) The thickness of the protective layer must be as thin as possible, since the effective flying distance of the head increases by the thickness of the protective layer and the recording and reproducing characteristics deteriorate.

2) Membrane strength, l! The adhesion force is sufficiently large that the protective film will wear out or peel off due to mechanical sliding with the head.

No scratches, etc. will occur.

3) Low coefficient of friction with the head.

4) Film formation is easy and low cost.

5) Excellent corrosion resistance.

etc. are required.

Conventional protective layers that almost satisfy these requirements include carbon,
Silicon vi ride and those made of silicon vi ride have been used in some magnetic disks.

[Problems to be solved by the invention] However, as mentioned above, the protective layer of a magnetic disk is required to have a thinner film thickness, but these protective layers formed by conventional film forming methods have a film thickness below a certain level. If the thickness is too thick, the mechanical durability against sliding with the head is insufficient.

In view of these circumstances, the inventors of the present invention have arrived at the present invention as a result of intensive studies on a method for forming a protective layer that fully satisfies the above-mentioned conditions even when the thickness of the protective layer is below a certain level.

[Means for Solving the Problems] According to the method of manufacturing a magnetic recording medium of the present invention, the protective layer provided on the metal 2I film magnetic layer is replaced by a target made of carbon, silicon oxide, or silicon nitride. The product of the distance between the substrates and the sputtering gas pressure is 5×10 Torr.
It is formed by sputtering under conditions of -1 or less.

In the magnetic recording medium of the present invention, the thickness of the protective layer is 1000A.
Obtained by making it less than.

When a protective layer is formed by sputtering a target made of carbon, silicon oxide, or silicon nitride under conditions where the product of the target-substrate distance and the sputtering gas pressure exceeds 5 x 110-2 TOrr-C, Unless the thickness of the protective layer is 1000Δ or more, sufficient mechanical durability, abrasion resistance, etc. cannot be obtained. But 100OA
Providing the above protective layer on the magnetic layer means that the effective flying distance of the head increases accordingly, and the recording and reproducing characteristics deteriorate, making it unsuitable for use as a high recording density medium.

Although the type of sputtering gas used in the present invention is not particularly limited, it is industrially desirable to use a gas mainly composed of argon because of its high sputtering efficiency.

Especially when the target is 5i02 or Si3N4, it is also possible to mix oxygen or nitrogen with argon as appropriate.
It is effective in improving the durability of the resulting protective layer.

The substrate used in the magnetic recording medium of the present invention can be made of aluminum, glass, ceramics, plastics, etc. The metal thin film magnetic layer formed on this substrate is made of Fe or Co.

Vapor deposition of magnetic metals such as Ni or alloys containing these.

A film formed by a method such as sputtering, plating, or ion blating is used.

[Effect 1] The reason why a protective layer with excellent mechanical durability can be obtained by the method of the present invention is not clear, but sputtering is performed under conditions where the product of the distance between substrates and the sputtering gas pressure is 5xlO-2Torr・α or less. When the sputtered particles reach the substrate, the energy lost due to collision with the sputtering gas is sufficiently small, and the film is formed using high-energy sputtered particles. This is also considered to be because the bonding state between the constituent atoms is improved.

[Example] The present invention will be explained in more detail with reference to Examples below.
The scope of application of the present invention is not limited in any way by these Examples.

Examples 1-4. Comparative Examples 1 to 5 A disk-shaped aluminum alloy was coated with a NiP plating film and then polished to an average surface roughness of 70A to obtain a substrate.

Next, a nonmagnetic underlayer was formed on this substrate by sputtering, and then a Go alloy magnetic layer containing 20 atomic percent of Ni was formed to a thickness of 500 Å.

Table 1 further targeted graph 7ite as a protective film.
Sputtering was performed using Ar gas under the conditions shown in Figure 1 to form a carbon layer manufactured using a different method on the magnetic layer. However, the thickness of all carbon layers was 900A.

For the magnetic disk obtained in this way,
A ferrite ball (3#IIIφ) was pressed against the point m with a load of 6 gf, rotated and slid at 1100 rpm, and the time until scratches appeared on the disk surface was measured.

The results are also shown in Table 1.

Examples 5-8. Comparative Examples 6-10 Examples 1-4. As in Comparative Examples 1 to 5, a metal thin film magnetic layer was formed on a NiP plating-coated aluminum alloy substrate, and then sputtering was performed in Ar gas using silicon oxide as a target as a protective film under the conditions shown in Table 2. A silicon oxide layer was formed. However, the film thickness of the silicon oxide lA layer was all 900A. The results of the mechanical sliding durability test of the magnetic disk thus obtained are also shown in Table 2.

Examples 9-12. Comparative Examples 11-15 Examples 1-4. As in Comparative Examples 1 to 5, a metal thin film magnetic layer was formed on a NiP plating-coated aluminum alloy substrate, and then sputtering was performed in Ar gas using silicon nitride as a target as a protective film under the conditions shown in Table 3. A silicon nitride layer was formed. However, the thickness of all silicon nitride layers was 900A. The results of the mechanical sliding durability test of the magnetic disk thus obtained are also shown in Table 3.

[Effects of the Invention] As is clear from the above explanation, according to the method of the present invention, the thickness of the protective layer provided on the metal magnetic f1 crotch is 100 mm.
Although it is less than 0A, it is possible to obtain a magnetic recording medium that has excellent durability against sliding with the head, so it is possible to manufacture a magnetic recording medium with higher recording density.

Claims (2)

[Claims] (1) In a method for manufacturing a magnetic recording medium consisting of at least a substrate, a metal thin film magnetic layer, and a protective layer provided on top of the substrate, the protective layer is replaced with a target made of carbon, silicon oxide, or silicon nitride. The product of the distance between the substrates and the sputtering gas pressure is 5 x 10^-^2 Tor.
1. A method for manufacturing a magnetic recording medium, characterized in that it is formed by sputtering under conditions of r.cm or less. (2) A method for manufacturing a magnetic recording medium according to claim (1), in which the protective layer is formed to have a thickness of less than 1000 Å.