JPH05109064A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To enable a thin magnetic recording medium to be manufactured at a high speed without any thermal damage by forming an injection electron layer at a film surface-layer part at a deposition surface side and then heating and depositing a high-speed electron beam. CONSTITUTION:An injection electron layer 10 is formed by injecting an electron beam onto a surface layer of a polymer film 1 which is 3-7mum thick at an acceleration voltage of 0.5-5kV. Then, a high-voltage electron beam is irradiated at an acceleration voltage of 30-75kV for heating a deposition material. At this time, a reflection electron 11 of acceleration voltage forms a reflection electron injection layer 12 by receiving a reduction operation by the injection electron layer 10. The injection layer 12 increases an electrostatic attraction with a cooling can 2, transmits a heat input at the time of deposition efficiently, and reduces thermal influence which the film 1 receives.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, narrowing of tracks for magnetic recording is 10 μm.
m, shorter wavelength has advanced to 0.5 μm, and the area recording density has improved to 1,000 times in 30 years, and downsizing and high functionality of the equipment have been realized without lowering image quality and sound quality. There is a strong expectation for the progress of the above, and wide practical application of magnetic recording media using a ferromagnetic metal thin film as a magnetic recording layer is strongly desired.

A conventional method of manufacturing a magnetic recording medium using a ferromagnetic metal thin film as a magnetic recording layer will be described below.

FIG. 2 is a schematic view of a main part of a vapor deposition apparatus used for manufacturing a conventional magnetic recording medium. In FIG.
1 is polyethylene terephthalate, polyethylene 2 and 6
Polymer film such as naphthalate, 2 cooling can, 3 film feeding axis, 4 winding axis, 5 evaporation source container, 6 vapor deposition material such as Co and Co-Ni, 7 electron beam, 8 A mask and 9 are oxygen gas introduction ports.

The operation of the vapor deposition apparatus constructed as above will be described. First, in a state where the polymer film 1 is vapor-deposited on the vapor deposition apparatus, the inside of the vacuum chamber is evacuated to 10 ^-5 to 10 ^-6 (Torr) by a vacuum exhaust system (not shown), and the vapor deposition material is irradiated with the electron beam 7 to Co. And Co-Ni
The vapor deposition material 6 such as the above is melted, further held at a high temperature to evaporate, and vapor deposition is performed while cooling the moving polymer film 1 with the cooling can 2. Ordinary oblique vapor deposition is configured such that vapor deposition is started from a high incident angle close to a tangent line, and the mask 8 limits the minimum incident angle to finish vapor deposition. At that time, oxygen gas is introduced from the oxygen gas introduction port 9 to improve the magnetic characteristics and practical characteristics required for the magnetic recording layer by the partial oxidation vapor deposition film. The vapor deposition film is practically used from a single layer to three layers. For the magnetic recording layer having a multi-layered structure, the above process is repeated or
A plurality of cooling cans and evaporation sources may be arranged in succession.

[0006]

However, in the above-mentioned conventional structure, when an attempt is made to manufacture a magnetic recording medium for the purpose of thinning the polymer film to improve the volume recording density,
There is a problem that the temperature rise of the polymer film increases and damage due to heat partially occurs.
In order to improve the productivity, it can be further cleared by high focusing voltage electron beam heating with high acceleration voltage and high power density.

The present invention solves the above-mentioned conventional problems, and is a method for solving the thermal damage caused by a thin tape when a magnetic recording layer is formed of a ferromagnetic metal heated and evaporated by a high-voltage accelerating electron beam. The purpose is to provide.

[0008]

In order to achieve this object, a method of manufacturing a magnetic recording medium according to the present invention has a structure in which an injection electron layer is previously arranged on a surface layer portion of a polymer film and high voltage electron beam heating vapor deposition is performed. Have

[0009]

With this structure, the reflected electron components of the high-voltage electron beam are accumulated in the film without passing through the thin polymer film used for vapor deposition, and the injected electrons are
It works to increase the electrostatic attraction between the cooling can and the heat input during vapor deposition, so that it can be effectively transferred to the can, and the thermal effect on the polymer film can be reduced.

[0010]

【Example】

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

In FIG. 1, reference numeral 10 denotes an injected electron layer in the surface layer portion of the polymer film 1, and the surface layer portion herein means within 1 μm of the surface of the polymer film 1, more preferably within 0.5 μm. The injection electron layer 10 is formed on this surface layer by injecting an accelerated electron beam, but by irradiating the polymer film 1 with the electron beam while adjusting the acceleration voltage from the low side to the high side. The standard of the obtained voltage range may be set and optimized within the range of 500V to 5KV. Reference numeral 11 is a schematic representation of backscattered electrons, which is composed of a part of the reflected components generated from the high-voltage electron beam irradiated to heat the vapor deposition material,
Although the ratio and direction of the reflected electrons 11 are not constant, they are reflected by the constituent material of the vapor deposition material, and a part of them is injected into the polymer film 1 that moves during vapor deposition. The electron beam of interest here has an acceleration voltage of 30 KV to 75 KV. When the thickness of the polymer film 1 used for magnetic tape production is 7 μm or less and 3 μm or less, the backscattered electrons 11 with the above-mentioned accelerating voltage have little energy lost, but penetrate the film 1, but the surface layer is injected. The electronic layer 10 receives the deceleration action and accumulates inside the film. A schematic representation of that is
12 backscattered electron injection layers.

The operation of the method of manufacturing the magnetic recording medium having the above structure will be described. Thickness 4.5 μm
Polymer film made of polyethylene naphthalate 1
(A fine particle coating layer is placed on both sides, and the average roughness is 4 (nm) on the vapor deposition side and 11 (nm) on the opposite side) with a diameter of 1
While moving along the cooling can 2 of m, Co at a minimum incident angle of 42 degrees and an introduced oxygen amount of 1 (I / min).
-Ni (Ni: 19 Wt%) was electron beam evaporated. The accelerated electron beam was selected to be 30 KV, 40 KV, and 75 KV. The electron beam, whose accelerating voltage changes linearly from 1 KV to 3.8 KV [synchronization is 2 (msec)], is irradiated with 48 (μA / cm ² ) as an average value to inject the electron layer 10 into the surface layer 0.4 μm. Formed. In addition, the conventional example used what was vapor-deposited without performing this process. For the vapor deposition, the setting conditions are the same 50
The length of 00 m (width 520 mm) was repeated twice for comparison. The vapor deposition film thickness was fixed at 0.15 μm. The deposition rate depends on the accelerating voltage, and at 30 KV, 60 (m / min)
In case of 40KV and 75KV, 110 (m / min) and 15 respectively
It was set to 0 (m / min). In the case of the embodiment, the reflected electrons 11
Reduces the energy in the injected electron layer 10 at the surface layer,
Since the reflection electron injection layer 12 is formed in the polymer film 1 without penetrating the μm polyethylene naphthalate film, the electrostatic attraction causes the cooling can 2 and the polymer film 1 to adhere to each other, releasing heat input, and Molecular film 1
It is possible to minimize the heat effect of the.

Table 1 shows the yield of tapes manufactured by the method of manufacturing the magnetic recording medium according to the present embodiment and the conventional manufacturing method.

[0014]

[Table 1]

As is clear from (Table 1), the magnetic recording medium manufacturing method according to the present embodiment is heat-damaged to the thin tape by high-voltage electron beam evaporation, which is one condition for achieving high-speed production conditions. It is possible to obtain an excellent effect that it can be manufactured in a state where the yield does not decrease due to.

As described above, according to this embodiment, a thin magnetic recording medium can be manufactured without thermal damage by forming an injection electron layer on the surface layer and then performing high voltage electron beam evaporation.

In the first embodiment, the polymer film 1 was polyethylene naphthalate having a thickness of 4.5 μm, but it was confirmed that it is effective if it is 7 μm or less and 3 μm or more regardless of the material of the polymer film 1. ing. The vapor deposition was described as oblique vapor deposition, but Co-Cr, Co-Ta, Co
Needless to say, it is also effective for vapor deposition for forming a perpendicular magnetization film such as —Mo, Co—Pt—B.

[0018]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a thin magnetic recording medium is manufactured at high speed without thermal damage by forming an injection electron layer on the surface layer of a polymer film and then performing high voltage electron beam evaporation. The method can be realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a method of manufacturing a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a vapor deposition main part for explaining a conventional manufacturing method.

[Explanation of symbols]

 10 injection electron layer 11 backscattered electron 12 backscattered electron injection layer

Claims (1)

[Claims] 1. A method for manufacturing a magnetic recording medium, comprising forming an injection electron layer on a film surface layer portion on the vapor deposition surface side, and then performing vapor deposition with a vapor flow obtained by high-speed electron beam heating evaporation.