JPH0740357B2 - 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.

Conventional technology Directly on a polymer film or via an underlayer, Co-Ni is obliquely vapor-deposited by electron beam evaporation, so-called vapor-deposition tape controls coercive force by introducing oxygen gas during vapor deposition. In addition, the durability and corrosion resistance are improved. [Foreign journals: IEEE TRANSACTIONS ON M
AGNETICS) Vol.MAG-20, NO, -5, pp824-826 (198
4)] An effective means for improving the durability of the vapor-deposited tape is to make the magnetic recording layer finely textured [Foreign papers: IE Transactions on Magnetics (IE
EE TRANSACTIONS ON MAGNETICS) Vol.MAG-21,
, pp1524-1526 (1985)], recently, in order to improve the durability performance, a diamond-like hard carbon thin film (hereinafter referred to as a DLC film) has been studied as a protective film.
It has been confirmed that the still durability is improved [IEICE,
Magnetic Recording Research Group sample, MR85-56 (1986)].

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, a magnetic recording medium is formed by directly forming a DLC film on a magnetic recording layer as a protective film of a vapor deposition tape having a partial recording film such as a Co—Ni—O film or a Co—O film as a magnetic recording layer. The recording medium has some problems when the signal output at short wavelengths fluctuates, and improvement has been desired. The present invention has been made in view of the above circumstances, and provides a method capable of manufacturing a magnetic recording medium with stable reproduction output in the longitudinal direction and improved durability.

Means for Solving the Problems In order to solve the above-mentioned problems, a method of manufacturing a magnetic recording medium according to the present invention is directed to a rotating support including a processing body having a partially oxidized ferromagnetic metal thin film on a polymer film. A diamond-like hard carbon thin film is formed immediately after dry etching of the surface oxide layer while moving along.

The method of manufacturing a magnetic recording medium according to the present invention has the above-described structure so that the surface oxide layer is not etched in the process of forming the diamond-like hard carbon thin film, so that the thickness of the thin film can be controlled to be constant. Therefore, it is possible to obtain a magnetic recording medium with a stable spacing, and by diverting the spacing loss due to the surface oxide layer to the thickness of the diamond-like hard carbon thin film, a magnetic recording medium with further improved durability can be obtained. It will definitely be obtained.

Embodiments Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium obtained by the production method of the present invention. In the figure, 1 is a polymer film such as a polyethylene terephthalate film having a thickness of 9.5 μm, 2 is a fine particle coating layer and has an average of 170 Å. The titania particles are fixed with 10 ⁹ particles / cm ² polyester resin.
Reference numeral 3 is a magnetic recording layer made of partially oxidized columnar crystal fine particles, 4 is a diamond-like hard carbon thin film, and 5 is a lubricant layer. At the interface between 3 and 4, the oxide layer on the surface of the columnar crystal fine particles is etched and has a negligible thickness (20 to 30 Å or less, preferably 0 Å in view of the spacing loss surface of magnetic recording) as described later.

The processing apparatus used to manufacture the magnetic recording medium shown in FIG. 1 is as shown in FIG. That is, in FIG. 2, 6 are placed along a diameter of the magnetic recording layer is in the cooling scan of 1 m, in an oxygen of ^{4 × 10 -5 (Torr),} Co-Ni (N
i: 20 wt%) formed by electron beam evaporation at a minimum incident angle of 40 degrees. It is an object to be processed having a layer with a film thickness of 0.16 μm and a surface oxide layer of 120 Å. Fine particle coating and polymer film are as described above. Is. 7 is an etching surface oxide layer (120Å)
After removing the, with the original fabric with a diamond-shaped hard carbon film,
8 is a feed shaft, 9 is a take-up shaft, 10 is a cooling can (diameter 50 cm, rotation direction is arrow A), 11 is a discharge electrode for etching, and a plurality of fine holes are formed on the surface of the electrode facing the cooling can. Open the individual pieces and use Ar + H ₂ (Ar: H
₂ = 2: 1) is introduced so that 0.014 l / min can be introduced. 12 is a plasma tube, 13 is an externally excited high frequency coil, 14
Is a mesh electrode and is set to 1200V. 16 is a vacuum tank, 17
Is an evacuation system, and 18 is an insulation introduction terminal.

With this configuration, Ar and methane gas are mixed through the gas inlet 15
Introduced 0.019 l / min in a 1: 1 mixed state, and added 13 to 13.56 (MH
z) 1900 (W) was charged to form a diamond-shaped hard carbon thin film 140 Å. On this layer, a cobalt salt of stearic acid was vapor-deposited and formed as a lubricant layer on another 40 Å by another vapor deposition machine. In Example 11, 13.56 (MHz) was input at 2400 (W), but in Comparative Example, a diamond-like hard carbon film was directly formed without introducing gas and applying high frequency under the same conditions as in Example.

When 100 ^m × 10 tapes were arbitrarily selected as the comparison tape and the tape of the example, the recording wavelength of 0.75 μm was recorded, and the reproduction output was monitored. In the example, all were within ± 0.2 (dB). However, the comparison tape had a large fluctuation of ± 1.4 (dB). When the still characteristics at −5 ° C. were compared, the time taken for the reproduction output to drop by 2 (dB) at any 30 locations was 75 minutes to 79 minutes in the Example, but was 19 minutes in the Comparative Example. There was a large variation between minutes and 72 minutes.

It should be noted that even in the initial output, the comparative example has a low value of −1.6 (dB) in comparison with the present example, indicating that the space loss is large. This means that the present embodiment further adds 70 to 10
This indicates that the 0Å diamond-like hard carbon film can be applied to improve the durability mainly by improving the durability.

It goes without saying that the present invention is not limited to the conditions described in the present embodiment, and the polymer film material and the magnetic recording layer material can be freely selected, and the manufacturing gas of the diamond-like hard carbon film and the like can be appropriately devised. It is possible.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to obtain a large amount of magnetic recording media having stable short-wavelength output and good output and durability.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of an example of a magnetic recording medium that can be manufactured according to the present invention, and FIG. 2 is a main part configuration diagram of an example of a processing apparatus used for carrying out the present invention. 1 ... Polymer film, 2 ... Fine particle coating layer, 3 ... Magnetic recording layer, 4 ... Diamond-like hard carbon film, 6 ... Object to be treated, 10 ... Cooling can, 11 ... Discharge electrode, 12
...... Plasma tube.

Claims (1)

[Claims] 1. A diamond-like hard carbon thin film is formed immediately after dry etching of a surface oxide layer while moving a treatment body having a partially oxidized ferromagnetic metal thin film on a polymer film along a rotary support. A method of manufacturing a magnetic recording medium, comprising: