JPH06251363A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a high density magnetic recording medium having durability and high output characteristics by subjecting the surface of a diamond like hard carbon film formed on a ferromagnetic metal thin film to hydrogen atom treatment and vacuum depositing a lubricant. CONSTITUTION:A partially oxidized ferromagnetic metal thin film is formed on a polymer film of a tape 1 to be treated thus forming a diamond-like hard carbon film and the surface thereof is subjected to hydrogen atom treatment on a rotary support 2 by means of a hydrogen atom generator 5. A lubricant 7 is then vacuum deposited in an evaporation source vessel 6 and then the film is wound around a winding shaft 4. This constitution enhances bonding strength on the surface of the diamond-like hard carbon film formed on the surface of the partially oxidized ferromagnetic metal thin film by means of quite active hydrogen atoms thus allowing strong bonding through hydrogen when the lubricant is deposited. Since durability can be provided even if the nonmagnetic part, causing space loss, is reduced a thin magnetic recording medium having durability and high S/N ratio can be produced with high reproducibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a magnetic recording medium having a magnetic layer of a ferromagnetic metal thin film suitable for high density magnetic recording and having excellent durability and recording characteristics.

[0002]

2. Description of the Related Art With the progress of information society, the amount of information to be recorded is remarkably increasing, and it is required to increase the recording density of magnetic recording as much as possible. Development of magnetic recording media has been brisk. Although many proposals have been made, the one currently put to practical use is a structure in which the surface of columnar fine particles is coated with an oxide of a ferromagnetic metal itself as disclosed in JP-A-53-58206. It has a well-balanced improvement in recording characteristics and durability, and its constituent elements consist of Co, Ni, and O (JP-A-56-15014), and these magnetic recording layers are formed by oxygen gas. C while intervening
A typical method is electron beam evaporation of o, Co-Ni, and there are some proposals for introducing oxygen, but in the vicinity of the substrate,
A position close to the part for controlling the incident angle is often used (Japanese Patent Laid-Open No. 54-19199, Japanese Patent Laid-Open No. 58-322).
34 publication). Further, while a protective film is being studied in order to improve the practical performance, further improvement has been made by increasing the hardness of the carbon film (Japanese Patent Laid-Open No. 53-143026) or by interposing other thin layers. (For example, JP-A-61-2
No. 42323, JP-A No. 62-167616, etc.). These films are applied by a predetermined film thickness after the ferromagnetic metal thin film is formed by vapor deposition by a plasma-applied sputtering method, an ion beam deposition method, a plasma CVD method or the like. Further, a lubricant is arranged by a solution coating method or a vacuum deposition method, and after necessary treatment, it is processed into a tape shape or a disk shape and used.

[0003]

However, in the above-mentioned conventional structure, it is necessary to increase the amount of oxygen introduced to increase the thickness of the surface oxide film, and to increase the hardness of the carbon film and also increase the thickness thereof. There is a large spacing loss,
There is a problem that it is difficult to obtain S / N characteristics sufficient to improve high density recording.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a method of manufacturing a thin magnetic recording medium having both durability and high output characteristics, which enables narrow track high density recording. And

[0005]

In order to achieve this object, a method of manufacturing a magnetic recording medium according to the present invention comprises forming a diamond-like hard carbon film on a partially oxidized ferromagnetic metal thin film and treating the bare surface with hydrogen atoms. In this case, the lubricant is vacuum-deposited.

[0006]

With this structure, the bonding strength of the diamond-like hard carbon film surface on the partially oxidized ferromagnetic metal thin film surface is increased by the extremely active hydrogen atoms, and when the lubricant is vapor-deposited on the diamond-like hard carbon film surface, the bonding force is strengthened strongly by hydrogen. Since it is possible to combine and reduce the non-magnetic portion that causes space loss, it can have durability, so that it is possible to reproducibly manufacture a thin magnetic recording medium having both durability and a high S / N ratio. Become.

[0007]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is a raw material for processing, in which a partially oxidized ferromagnetic metal thin film is arranged on a polymer film, and diamond-like hard carbon is formed thereon, and 2 is a rotary support for temperature control. The conditions, insulation retention, etc. can be appropriately selected. Reference numeral 3 is a delivery shaft, and 4 is a winding shaft. Reference numeral 5 is a hydrogen atom generator, 6 is an evaporation source container, 7 is a lubricant for vapor deposition, and 8 is a free roller. The heating energy for evaporation is not particularly limited, such as accelerated electron beam and Joule heat.
The hydrogen atom generator has a function of neutralizing hydrogen ions with an electron shower and removing charged particles by magnetic field deflection to generate a hydrogen atom beam obtained. As for the lubricant, naturally occurring lubricants as well as those obtained by chemical synthesis may be used.

In order to further clarify the effect of this embodiment, a magnetic recording medium will be made by using the apparatus having the above-mentioned constitution, and the result of the characteristic comparison with that obtained by the conventional method will be described in detail. .

A thickness of 7 μm, 54 in the longitudinal direction and 54 in the width direction, respectively.
Young's modulus of 0,590 [Kg / mm ² ] and average roughness of 3
0Å polyethylene terephthalate film (diameter 15
Using 0 Å ultrafine particles of SiO ₂ with an average density of 20 particles / μm ² resin-fixed coating layer was placed in advance), the oxygen was wound up along a rotary can cooled to 20 ° C. with a diameter of 1 m. Then, Co was electron beam evaporated to form a magnetic layer of 0.18 μm. The oxygen gas introduction nozzle has a minimum incident angle of 40 degrees, and the mask for determining the incident angle has a 0.8 mm diameter stainless pipe at the tip of which a 0.2 mm diameter hole is arranged at a pitch of 15 mm. / Min It controlled and introduced. The oxide layer on the surface was 110 to 115Å. Then, methane gas was discharged and decomposed by plasma CVD to form a diamond-shaped hard oxygen film of 70Å. The film in this state is referred to as a raw fabric A, and the raw fabric A is divided in the longitudinal direction, and hydrogen atom treatment is carried out in the examples, hydrogen glow discharge treatment is carried out in the comparative examples, and no treatment is carried out in the conventional examples. Disperse perfluorostearic acid in a uniform thickness of 40Å by vacuum deposition to form a backcoat layer of 0.45
A magnetic tape having a thickness of 8 μm and having a width of 8 mm was manufactured as a prototype and its characteristics were compared. The characteristics of the magnetic tapes are compared with each other by modifying the high-band 8 mm video deck and recording wavelength 0.47 μm, track pitch 9 μm and S / N ratio at the initial stage, 40 ° C., 80% RH.
After the recording and reproduction were repeated 130 times, the relative comparison was performed. The length of the magnetic tape was 100 m, 5 rolls were randomly selected, and the average value of 5 rolls was displayed. The still characteristics were compared at 40 ° C. and 5% RH by increasing the tension to 25 g. The characteristics of the magnetic recording medium according to this example and the characteristics of the magnetic recording medium of the comparative example are shown in comparison with each other (Table 1).

[0011]

[Table 1]

As is clear from (Table 1), the magnetic recording medium manufactured according to the present example has an excellent effect of achieving durability and high S / N ratio in high density recording in narrow track recording. It is understood that is an excellent manufacturing method.

As described above, according to the manufacturing method of this embodiment,
A diamond-like hard carbon film is formed on a partially-oxidized ferromagnetic metal thin film, the surface is treated with hydrogen atoms, and a lubricant is vacuum-deposited.
It is possible to obtain a large number of magnetic recording media with good reproducibility that can stably maintain the / N ratio even after repeated use.

(Second Embodiment) A second embodiment of the present invention will be described below.

FIG. 2 is a schematic view of the essential parts of a magnetic recording medium manufacturing apparatus used to carry out the method of manufacturing a magnetic recording medium according to the second embodiment of the present invention. In FIG. 2, 9 is Co-O, Co-Ta-O, Co-Cr-O, Co on the polymer film.
-Ni-O single-layer or multi-layer partially-oxidized ferromagnetic metal thin film is disposed on the processing stock, and 10 and 11 are temperature-controlled rotary supports, 12 is a delivery shaft, and 13 is a take-up reel. The axis 14 is a graphite target for forming a carbon film on the partially oxidized ferromagnetic metal film with a hardness close to that of diamond. The diamond-like hard carbon film is not limited to the case where the diamond-like hard carbon film is directly formed on the ferromagnetic metal film, but the diamond-like hard carbon film may be formed after the plasma polymerization treatment or the like. In any case, it is necessary to form the film thicker than a predetermined film thickness and 20 to 50% thicker. Of course, the method for forming the diamond-like hard carbon film is not particularly limited to the ion plating method other than the sputtering method, the plasma CVD method and the like. Reference numeral 15 is a discharge electrode for sputter etching, in which hydrogen gas, a mixed substrate of hydrogen gas and argon gas, or the like is used as a discharge gas in order to adjust the thickness of a diamond-like hard carbon film, which is previously thickened, to a predetermined thickness, and etching is performed mainly by ions To do. Reference numeral 16 is an evaporation source container, 17 is a lubricant, and the amount of evaporation is controlled by heat transfer such as heat medium circulation, use of Joule heat, induction heat generation and the like, and is not particularly limited. 18 is a vacuum tank, 19 and 20 are vacuum exhaust systems, 21 and 22 are gas introduction systems, 23 is an insulation introduction terminal, and 24 is a vacuum partition.

In order to further clarify the effect of this embodiment, a magnetic recording medium is prototyped using the apparatus having the above-mentioned constitution, and the results of the characteristic comparison with those obtained by the conventional method will be described in detail. .

A polyimide film (Si having a diameter of 150 Å) having a thickness of 6.1 μm and a Young's modulus of 940 and 1050 [Kg / mm ² ] in the longitudinal and width directions and an average roughness of 25 Å
O ₂ ultrafine particles were used by pre-arranging a coating layer having an average density of 20 particles / μm ² fixed on a resin) and oxygen was introduced while winding along a rotary can heated to 200 ° C. having a diameter of 1 m. Co was electron beam evaporated to form a magnetic layer of 0.18 μm. The oxygen gas introduction nozzle has a minimum incident angle of 20 degrees, and a 0.8 mm diameter stainless steel pipe having 0.2 mm diameter holes at a 15 mm pitch is arranged at the tip of the mask for determining the incident angle.
It was introduced by controlling to 1 / min. The maximum incident angle was 42 degrees, and the surface oxide layer was a Co—O film having an easy axis of magnetization in the perpendicular direction and the surface oxide layer was 120 to 125 Å.

This state is referred to as a raw fabric B, and the raw fabric B is subjected to a high frequency sputtering method using a device of FIG.
(2a), 100Å (2b), 130Å (2c), 20
0 Å (2d) was formed, carbon electrodes were continuously used, the discharge gas was made equal to hydrogen and argon, and the thickness was 60 Å (2a) and 80 Å (2b) 8 by the sputter etching method.
0Å (2c) and 110Å (2d) were set, and myristic acid was vacuum-deposited on it by 30Å by resistance heating method. Conventional example is 6
A diamond-like hard carbon film having a thickness of 0 Å (2e), 80 Å (2f) and 110 Å (2 g) was formed, and then myristic acid was similarly vacuum-deposited in a volume of 30 Å. In each case, a back coat layer having a thickness of 0.45 μm was formed into a magnetic tape having a width of 8 mm. Digital recording with a 5 μ track and a bit length of 0.2 μ was performed by an 8 mm video obtained by modifying these tapes, and the error rates were compared with each other. The durability was also evaluated by the error rate after adding 100 pass histories at 5 ° C. and 85% RH. The characteristics of the magnetic recording medium according to this example and the characteristics of the conventional magnetic recording medium are shown in comparison with each other (Table 2).

[0019]

[Table 2]

As is clear from (Table 2), the magnetic recording medium manufactured according to this example has an excellent effect that high density digital recording under a narrow track condition can be performed with a good error rate. is there.

As described above, according to this embodiment, after the diamond-like hard carbon film is formed on the partially oxidized ferromagnetic metal thin film so as to have a predetermined thickness, the surface is sputter-etched to a predetermined thickness, By vacuum-depositing the lubricant,
The surface of the hard carbon film becomes extremely active, and it adheres strongly to the lubricant, dramatically improving the sustainability of lubrication performance and removing the defects near the surface of the hardness of the hard carbon film. Therefore, the magnetic recording medium can be made thin, and it is possible to reproducibly manufacture a thin magnetic recording medium which has both durability and a high S / N ratio.

[0022]

As described above, according to the present invention, a diamond-like hard carbon film is formed on a partially oxidized ferromagnetic metal thin film,
By subjecting the surface to hydrogen atom treatment and then vacuum-depositing the lubricant, a large amount of magnetic recording media can be obtained with good track record and high density recording, which can stably maintain excellent S / N ratio even after repeated use. You can

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a processing apparatus used for manufacturing a magnetic recording medium according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of a processing apparatus used for manufacturing a magnetic recording medium according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Processing Fabric 5 Hydrogen Atom Generator 7 Lubricant 9 Processing Fabric 14 Graphite Target 15 Discharge Electrode 17 Lubricant

Claims (2)

[Claims] 1. A method of manufacturing a magnetic recording medium, comprising forming a diamond-like hard carbon film on a partially oxidized ferromagnetic metal thin film, treating the surface with hydrogen atoms, and then vacuum-depositing a lubricant. 2. A method for forming a diamond-like hard carbon film on a partially oxidized ferromagnetic metal thin film so as to have a predetermined thickness, subjecting the surface to sputter etching to a predetermined thickness, and then vacuum-depositing a lubricant. A method for manufacturing a characteristic magnetic recording medium.