JPH0799578B2 - Method of manufacturing magnetic recording medium - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium suitable for high density magnetic recording.

2. Description of the Related Art Perpendicular magnetic recording methods have been developed that use perpendicular magnetization instead of in-plane magnetization of magnetic recording media for the purpose of increasing the recording density. This recording method requires a medium that can be magnetized in the direction perpendicular to the substrate, and the coating type uses barium ferrite powder [eg Toshiba Review, Vol. 40, No. 13,
1104 to 1106 (1985)], Co-Cr sputtered film is a typical thin film type [eg, IEEE transaction
Transactions on Magnetics v
ol.MAG-15, 1456 (1979)].

Although the thin film type is suitable for high density, in reality, the problems of abrasion and abrasion are serious, and the development of protective film is active. However, if the protective film is made thick, the high-density characteristics are lost, and a practical system has not been found yet. On the other hand, studies have been conducted to form a perpendicular magnetization film from an oxide or nitride, which has good durability of the ferromagnetic thin film itself, and it has been confirmed from the magnetic characteristics that it is a perpendicular magnetization film [eg, Journal of Applied Physics (Jo
urnal of Applied Physics) vol.57, No.1,4034-4036
(1985)].

The formation of the Co oxide perpendicular magnetization film is performed by electron beam evaporation method,
It can be done by sputtering method, but by electron beam evaporation method,
Electromagnetic conversion characteristics are insufficient, and a sputtering method is expected.

Problems to be Solved by the Invention However, whether Co-O, Co-Ni-O system, Co-Cr system, or the basic manufacturing method is a sputtering method or an electron beam evaporation method, More than the thickness required for the magnetic recording layer (especially when directly formed on the polymer film)
The fact is that the characteristics are obtained by forming a thin film.
From this, the film formation rate has been substantially reduced, and improvement has been desired. The present invention has been made in view of the above circumstances, and provides a method of manufacturing a magnetic recording medium capable of producing desired characteristics only with a thickness required for a magnetic recording layer.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for producing a magnetic recording medium of the present invention comprises: forming an excessive hydrogen-containing layer on the surface layer part of a moving polymer film; It is designed to be formed.

Action According to the method of manufacturing the magnetic recording medium of the present invention, since the hydrogen gas from the polymer film acts in the initial stage of the formation of the ferromagnetic metal thin film, the perpendicular orientation of the perpendicular magnetization film and the uniaxial magnetization film uniaxial Since the anisotropy is remarkably improved, the layer with disordered orientation found in the initial thin film growth portion as in the past is eliminated, so it is sufficient to form a ferromagnetic metal thin film with a desired thickness. High-speed production of an improved magnetic recording medium becomes possible. Also, the crystals become dense due to the action of hydrogen gas, and the durability is also improved.

EXAMPLES Examples of the present invention will be described below with reference to the drawings. The figure is a schematic diagram of a main part of a sputtering apparatus used for carrying out the present invention. In the figure, 1 is polyethylene terephthalate, polysulfone, polyether sulfone,
Polymer films of polyphenylene sulfide, polyamide imide, polycarbonate, polyethylene naphthalate, etc., 2 are cylindrical cans, which are constructed so as to maintain a constant surface temperature and whose diameter is 30 cm to 1 m are often used. 3 is a feeding shaft, 4 is a winding shaft, 5 is Co, Co-Cr, Co
Targets such as -Cr-Nb, Co-Cr-Pr, Co-Ta, Co-Mo, Co-Ni are magnetic field generators for inducing magnetron emission, and it is necessary to provide a gap in the target. You can do it accordingly. Reference numeral 7 is a high frequency power source, 8 is a vacuum container, 9 is a gas introduction port, 10 is a variable leak valve, and 11 is a vacuum exhaust hole, which is connected to the vacuum pump P. 12 is a high voltage introduction terminal. 13
Is a mask, 14 is a hydrogen ion generator, 15 is a hydrogen ion beam, 16 is an exclusive exhaust system for an ion system, and 17 is a hydrogen ion irradiation tube. The formation of a layer containing excessive hydrogen in the surface layer of the polymer film depends on whether hydrogen ion irradiation or neutral hydrogen beam irradiation is used, and glow discharge of hydrogen or glow discharge treatment containing hydrogen gas is not sufficient. is there.

More specifically, the data of the example of the magnetic recording medium compared with the conventional example will be shown.

Using the device shown in the figure, a can temperature of 30 m
Keeping the temperature at ℃, form a Co-Cr (Cr20.9wt%) perpendicular magnetic film by 13.56 (MHz) high frequency magnetron sputtering method, and perfluorooctanoic acid is vacuum-deposited on it by 50Å to produce 8mm width magnetic tape. Then, a ferrite head with a gap length of 0.2 μm was used to record at a recording wavelength of 0.6 μm. The reproduction C / N (signal to noise ratio) was compared and the still endurance time until the output decreased by 2 (dB) was compared in the still state. did.

After irradiating 12 KeA hydrogen ions at 12 μA / cm ^2, the C / N of the tape A formed with the perpendicular magnetization film of 0.12 μm was taken as a reference, and the conventional example was the tape B composed of the perpendicular magnetization film of 0.12 μm.
Was -1.1 (dB) for tape C composed of a perpendicular magnetization film of -3.9 (dB) and 0.17 μm. Still life is tape A,
It was 38 minutes, 20 minutes and 18 minutes respectively for B and C.

The high-speed production degree of the tapes A, B, and C was 8 m / min for the tape A and 5.5 m / min for the tape C.

It has been confirmed that the difference in the film forming speed is larger when the Co—Cr film is formed by the electron beam evaporation method, and about twice as fast as in the present embodiment.

Also, when compared with the oblique deposition method, the magnetic characteristics, especially the coercive force, increased by 30% and the squareness ratio was 25%, rather than the high speed.
The value of the present invention is great as it is improved.

EFFECTS OF THE INVENTION As described above, according to the present invention, there is an excellent effect that performance improvement of the magnetic recording layer and high-speed production can be achieved at the same time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an example of a sputtering device used in the examples of the present invention. 1 ... Polymer film, 2 ... Cylindrical can, 5 ... Ferromagnetic metal target, 14 ... Hydrogen ion generator, 15 ... Hydrogen ion beam.

Claims (1)

[Claims] 1. A method of manufacturing a magnetic recording medium, which comprises forming an excess hydrogen-containing layer on the surface of a moving polymer film and then forming a ferromagnetic metal thin film.