JPS6378341A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having good S/N by incorporating oxygen into an electric discharge gas at the time of disposing plural targets oppositely to a moving substrate and forming a thin ferromagnetic metallic film by sputtering vapor deposition using the magnetron discharge. CONSTITUTION:The oxygen is incorporated into the electric discharge gas at the time of disposing the plural targets 10, 11 oppositely to the moving substrate 7 and forming the thin ferromagnetic metallic film by the magnetron vapor deposition using the magnetron discharge. The space distribution of the evaporating particles generated by the magnetron discharge is thereby improved and the coercive force and noise are improved by the relieved magnetostatic coupling of the gaseous oxygen with the fine magnetic particles according to the compounding ratio thereof. The effect thereof is higher as the number of the plural targets is increased and the moving speed (productivity) is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film suitable for high-density magnetic recording.

Conventional technology In recent years, there has been remarkable progress in increasing the density of magnetic recording, and the wavelength
Since track widths have been developed to be less than .mu.m and track widths are close to 10 .mu.m, magnetic recording media in which the demagnetization effect is reduced by thin films with high saturation magnetic flux density have attracted attention, and some of them have begun to be put into practical use. As a magnetic recording layer, a Co--Cr perpendicular magnetization film, a Co--Ni in-plane magnetization film, etc. are considered promising.

Co-Cr film and Co-Ni film are A r r A
It is well known that a magnetic recording layer is formed by sputtering in a N2 atmosphere, and that the magnetic properties are controlled by heat treating these films. (Unexamined Japanese Patent Publication No. 57-72,307, Journal of Applied Phys.
cs) Volume 63 No. 10, 6941-6945 (198
2).

(Japanese Unexamined Patent Publication No. 61-153,827) For example, magnetic disks are manufactured by flat plate magnetron sputtering on an aluminum alloy substrate using N2:Ar
An example of this is to set the total pressure to 16 mTorr with the ratio 1:1, to form a film with a thickness of 1000 on C0-30 at%Ni as a target, and to heat treat it for 340' CI time with an input power of 1 Kw.

Problems to be Solved by the Invention However, with the above configuration, although the short wavelength output can be increased, the noise is large, so it is difficult to obtain a magnetic recording medium with a sufficient signal-to-noise ratio (hereinafter referred to as S). Improvements have been desired since flexible substrates such as polyester cannot be used due to the high heat treatment temperature.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing magnetic recording media such as magnetic disks and magnetic tapes with good S/N.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for manufacturing a magnetic recording medium of the present invention involves disposing a plurality of targets on a moving substrate, and depositing nine ferromagnetic metal thin films by magnetron discharge. When depositing by sputtering, oxygen is included in the discharge gas.

It is believed that the above-described structure improves the coercive force and noise due to the spatial distribution of evaporated atoms generated by magnetron discharge and the fusion of the magnetostatic coupling of the magnetic fine particles due to the blending of oxygen gas.

The more targets you have and the faster your movement speed (productivity), the stronger the effect will be.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a magnetic recording medium obtained by the present invention.
This is an enlarged cross section of. In Figure 1, 1 is a polymer film or A
The magnetic recording layer 3 of the nonmagnetic substrate 2 made of l-Mq gold alloy is formed by sputtering and is a protective film.

FIG. 2 is a diagram showing a main part of an example of a sputtering apparatus used to carry out the present invention. In the figure, 4 is a vacuum container, 5 is a vacuum exhaust system, 6 is a cooling support plate, 7 is a substrate, and 8
is an unwinding roll, 9 is a take-up roll, 10.11 is a target, 12.13 is a magnetic field generator, 14.15 is a high frequency power supply, 16 is a gas introduction boat, 17 is a variable leak valve,
18 is an insulation introduction terminal. The magnetic field generator is configured to generate a magnetic field perpendicular to the traveling direction of the substrate.

This makes it possible to generate a so-called magnetron discharge, and the spantalate has a spatial distribution, making it possible to change the ratio to the introduced gas.

26μm thick polyethylene terephthalate fiber/I/
Co-N1 (Co 80wt%) was targeted on A, and 13.56 (MH
Sputter deposition was performed by high frequency glow discharge of z). At that time, Ar I X1O-3(”rr)024X10
(Torr).

There are two targets (one target has a width of 27 mm).
5 cm, length 12.61. ) Film thickness is 0.1 turbidity μ
The film was formed under conditions such that m.

The moving speed is 12 m/min, and the length s is 60 m (
After completing the film formation with a width of 19 cTL), perfluorooctanoic acid was vacuum-deposited to a thickness of 65 cm to produce a 5.25-inch disk (1e disks were selected by random selection in the longitudinal direction),
A rectangular wave with a bit length of 0.3 μm was recorded and reproduced using a ferrite head with a gap length of 0.14 μm.

As a comparative example, a chromium film with a thickness of 400 μm was sputtered on a polyamide-imide film with a thickness of 20 μm, and Co-Ni (Co 80 wt%) with a thickness of 0.07 μm was formed on it by sputtering.
High frequency magnetron sputtering in r, then Or 23
A magnetic disk was prepared by sputtering 0.0 μm Co--Ni and then vacuum-depositing perfluorooctanoic acid thereon. This manufacturing condition was chosen because of the coercive force aso (Oe) obtained in the example.

This is to achieve almost the same magnetic characteristics with a squareness ratio of 0.83. When comparing the two in terms of S/N, the example was superior by s, 9 (dB), and the noise was improved in the entire band. The main improvement factor is that

Of course, the present invention is not limited to the examples described above, and may take the form of a hard disk, magnetic tape, or the like.

The number of targets may also be increased as necessary.

Regarding ferromagnetic metal thin film materials, Co -N i , Co
-Fe.

Co-Cr, Co-Pr, Co-Ni-Pr, etc. may be selected as appropriate.

Effects of the Invention As described above, according to the present invention, magnetic properties can be ensured at low temperatures, so a magnetic recording medium can be obtained using a general-purpose plastic such as polyethylene terephthalate as a substrate, and S
An excellent effect can be obtained in that a magnetic recording layer having a good /N ratio can be obtained with high productivity.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of an example of a magnetic recording medium manufactured according to the present invention, and FIG. 2 is a schematic diagram of an example of a sputtering apparatus used in carrying out the present invention. 1...Substrate, 2...Magnetic recording layer, 7.
...Substrate, 10.11 ...Target,
16... Gas introduction boat. Name of agent: Patent attorney Toshio Nakao and 1 other person2-
・Mourning record layer

Claims (1)

[Claims] A method for manufacturing a magnetic recording medium, characterized in that a plurality of targets are arranged facing a moving substrate, and oxygen is included in the discharge gas when a ferromagnetic metal thin film is sputter-deposited by magnetron discharge.