JPH07105045B2 - 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 producing a magnetic recording medium having a ferromagnetic metal thin film suitable for high density magnetic recording as a magnetic recording layer.

2. Description of the Related Art Since a magnetic recording medium using a ferromagnetic metal thin film as a magnetic recording layer has a large short-wavelength output, it is positioned as an indispensable medium for high-density magnetic recording, which is expected to make further progress, and is under development. [Foreign articles, IEE
Transactions on Magnetics (IEEE TRA
NSACTIONS ON MAGNETICS) vol.MAG-21, pp1217-1220
(1985)]. In general, a magnetic recording medium having such a structure is formed by winding a polymer film along a cylindrical can while performing a sputtering method, a field evaporation method, an ion plating method,
A magnetic recording layer is obtained by forming a ferromagnetic metal thin film on a polymer film by an electron beam evaporation method or the like [Japanese Patent Laid-Open No. 53-42010, Institute of Electronics and Communication Engineers, Material for Magnetic Recording Research Group, MR8
1-2 (1981), JP-A-61-186475.

FIG. 2 is a configuration diagram of essential parts of a winding vapor deposition apparatus used for manufacturing a magnetic recording medium by the oblique vapor deposition method. In FIG. 2, 1 is a polymer film such as polyethylene terephthalate or polyimide, 2 is an unwinding shaft, 3 is a winding shaft, 4 is a chill drum, 5 is an evaporation source, 6 is an electron beam generator, 7
Is a focused high-energy electron beam, 8 is a shutter, 9 is a heat shield, 10 is a vacuum container, 11 is a vacuum partition, 1
2 and 13 are exhaust holes, and 14 is a rotating roller. In the device of Fig. 2, while introducing oxygen from the outside, the position of the evaporation source, the energy of the electron beam, etc. were devised to make the minimum incident angle small, and various devises were made to improve the vapor deposition efficiency and put it into practical use. It is approaching [JP-A-55-12547, JP-A-57-19
493, JP-B-57-23931, JP-B-57-29770, JP-A-59-1240
No. 37]. On the other hand, control of the surface shape of the polymer film was also found to improve the durability of the magnetic recording layer, and granular projections, earthworm-like ridges, combinations thereof, etc. were considered promising, and the material, projection height, projection density, etc. Many experiments have been repeated for the optimization of [JP-A-58-100221,
59-92427, 59-223932, 59-207422, 61-74139
Gazette].

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above configuration, as the recording density increases, the durability, the excellent signal-to-noise ratio (C / N), the uniformity of the error rate in digital recording, and the practicality are improved. Since it becomes difficult to cover a large area, improvements have been desired. The present invention has been made in view of the above circumstances, and provides a magnetic recording medium having excellent high-density magnetic recording / reproducing characteristics and excellent practical reliability.

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 obliquely vapor-depositing a polymer film moving along a rotary support, and subjecting it to oblique vapor deposition. Other than this, sputter vapor deposition is performed by an endless target on which a part of the vapor flow is deposited.

Action In the present invention, the vapor deposition film is made into fine particles by the above-mentioned constitution, and the practical reliability is improved by the improvement of C / N and the durability.

Example Hereinafter, a method of manufacturing a magnetic recording medium according to an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a main part of a vapor deposition apparatus used to obtain a magnetic recording medium by carrying out a manufacturing method according to an embodiment of the present invention. In FIG. 1, 15 is a polymer film of polyethylene terephthalate, polyphenylene sulfide, polysulfone, etc., 16 is an unwinding shaft, 17 is a take-up shaft, 18 is a rotary support, 19 is an evaporation source, and 20 is oblique in the vapor flow. 21 is an endless belt type target for vapor deposition, and 22 is a part of vapor flow for sputter vapor deposition. twenty three
Is a vacuum tank, 24 is a vacuum exhaust system, 25 is a gas introduction port,
26 is a mask that determines the minimum incident angle of oblique vapor deposition, 27 is a rotating roller, and 28 is a tension roller, which are insulated from each other and configured so that a high frequency is applied to 21. 29 is a magnetic field generator, which has the function of localizing the discharge in order to increase the sputtering speed, and 30 is a free roller.

In FIG. 1, the diameter of the rotary support is 60 cm, the center of the evaporation surface of the electron beam evaporation source is A, and the respective positions shown are B to
G = AB = 30cm, minimum incident angle 23 degrees, AC = 52cm, AD = 60c
m, ED = EF = 23 cm, EG = 15 cm, and the tip of the gas introduction port was placed 17 cm just above point D. The strength of the magnetic field generator is 160 (e) on the target surface and 13.56 (MH) for the high frequency power source.
z) 3 (KW) was used.

13 μ / (μm) ^{2 of} 100 Å diameter SiO ₂ fine particles were coated on a polyethylene terephthalate film with a thickness of 10 μm, and Co-Ni (Ni: 20 wt%) 0.15 l / min was introduced into the electron beam while introducing oxygen. Along with vapor deposition, sputter vapor deposition was performed.

In the comparative example, sputter deposition was not performed, and only electron beam deposition was performed. The ferromagnetic metal thin film of the example has a thickness of 0.13 μm, the comparative example has a thickness of 0.11 μm, and the coercive force of the example is 1100 (
e), the comparative example is 950 (e), and the squareness ratio is 0.81 in the embodiment.
The comparative example was 0.7. In both cases, perfluorooctanoic acid was vacuum-deposited at about 50Å, an 8 mm wide magnetic tape was manufactured, and C / N was compared with a commercially available 8 mm video (VX-801, manufactured by Matsushita Electric Industrial Co., Ltd.). It is better than the comparative example by 3.4 (dB), which is due to the fact that the noise due to atomization is low, the magnetic characteristics are improved, and the frequency characteristics are also improved.

The present invention is not limited to the above-mentioned embodiment, and it is also possible to configure the same system as the oxide sputter deposition as an overcoat after the oblique deposition is completed.

Further, it can be said that the effect that the utilization efficiency of the steam flow is increased cannot be overlooked.

EFFECTS OF THE INVENTION As described above, according to the present invention, there is an excellent effect that a magnetic recording medium having an improved C / N can be efficiently obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a vapor deposition apparatus used in an embodiment of the present invention, and FIG. 2 is a configuration diagram of essential parts of a conventional vapor deposition apparatus. 15 …… Polymer film, 18 …… Rotary support, 19 …… Evaporation source, 21 …… Endless target, 25 …… Gas inlet port.

Claims (1)

[Claims] 1. A polymer film moving along a rotary support is obliquely vapor-deposited, and is sputter-deposited by an endless target on which a part of a vapor stream other than the one used for the oblique vapor deposition is deposited. Method for manufacturing magnetic recording medium.