JPS5922235A - Production of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a vertically-magnetized Co-Cr film having a uniform composition in the length and film thickness directions, by arranging electron guns on the opposite side of a Cr material to a perpendicular line passing through the center of a cylindrical can in the moving direction of a substrate during vapor deposition. CONSTITUTION:In the device shown by the figure, the electron gun 17 for heating the Cr material 14 is arranged on the opposite side of the Cr material 14 to the perpendicular line 21 passing through the center of the cylindrical can 2 in the moving direction of a substrate. Thus, the arrangement of a CR evaporating source shown by the figure makes it possible to obtain the vertically-magnetized Co-Cr film having a uniform composition in the length and film thickness directions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for manufacturing a medium suitable for perpendicular magnetic recording.

A perpendicular magnetic recording system is a magnetic recording system with excellent short wavelength recording characteristics. This method requires a perpendicular recording medium whose axis of easy magnetization is perpendicular to the film surface of the medium.

When a signal is recorded on such a medium, the residual magnetization is oriented perpendicularly to the film surface of the medium, so that the shorter the signal wavelength, the smaller the demagnetizing field within the medium, and the better the reproduced output.

Perpendicular recording media are made of a substrate made of a non-magnetic material such as a polymeric material or a non-magnetic metal, directly or through a soft magnetic layer such as Noku-Malloy, and are composed mainly of CO and Or and perpendicular to the film surface. A magnetic layer having an axis of easy magnetization in the direction (hereinafter this magnetic layer will be referred to as a Go-Gτ perpendicular magnetization film) is formed by sputtering or vacuum evaporation.

A Go-Or perpendicular magnetization film can be obtained by both the sputtering method and the vacuum evaporation method, but the latter method in particular allows the film to be obtained at a highly productive deposition rate of several thousand people/second. . In the vacuum evaporation method, the substrate is moved along the circumferential surface of a cylindrical can while the Go
By vapor depositing -Or, a long perpendicularly magnetized film can be stably produced. FIG. 1 schematically shows a manufacturing apparatus using such a vacuum vapor deposition method.

In the figure, reference numeral 1 denotes a substrate, which runs along the circumferential side of the cylindrical can 2 in the direction of arrow 3 or 3'. A Go-Or alloy ingot 6, which is a thin film material, is placed in a crucible 5, and is heated and evaporated by an electron beam 8 generated from an electron gun 7.

Note that the crucible 5 and the electron gun 7 are collectively referred to as an evaporation source.

The evaporated OO and Or atoms adhere to the moving substrate 1, forming a Co--Cr perpendicularly magnetized film. 9,1
0 are rolls for winding the substrate 1, respectively. 4 is a mask for preventing unnecessary atoms from adhering to the substrate. 11 and 12 are a vacuum chamber and an exhaust system, respectively.

Note that the reason why an electron beam evaporation source is used as the evaporation source is that a high deposition rate can be stably obtained.

QO-C is manufactured using manufacturing equipment as shown in Figure 1.
When an R film is produced, a perpendicularly magnetized film is obtained, but when a long film is continuously produced by evaporating CO and Or from one evaporation source, films with different compositions in the longitudinal direction are obtained. I can do it. That is, since the vapor pressure of Cr is higher than that of CO, Or
It evaporates first and it's sweet. As a result, a long Co-Cr
When films are produced continuously, a film formed in the early stage of vapor deposition contains a large amount of Or, and a film formed in the late stage of vapor deposition contains a small amount of Or.

This is undesirable because in the Go-Cr perpendicularly magnetized film, different compositions result in different magnetic properties.

As a means to solve this problem, there is the Mihara vapor deposition method. In the Mihara deposition method, as shown in FIG. 2, a film is formed by evaporating CO and Cr from separate evaporation sources. 13.15
are crucibles for containing Cr material 14 and CO material 16, respectively. Reference numerals 17 and 18 are electron guns for heating and vaporizing the Or and CO materials, respectively.

19 and 20 are electron beams generated from electron guns 17 and 18, respectively. 21 indicates a vertical line passing through the center of the cylindrical can 2. As a result of conducting an experiment to continuously fabricate a long Go-Cr perpendicularly magnetized film using a manufacturing apparatus configured as shown in Figure 2, we were able to obtain a film with a uniform composition in the length direction. However, it became clear that there was a considerable compositional change in the film thickness direction.

For example, in a manufacturing apparatus with a structure as shown in FIG.
A Go-Cr perpendicular magnetization film is produced on a substrate made of a polymeric material that is moving along the circumferential side of the cylindrical can 2,
Analysis of the composition of the resulting film revealed that the Cr concentration on the film surface was 18 wt%, but the CTa concentration near the boundary between the Co-Or film and the substrate was 29 wt%. Although it is possible to use the film as a perpendicularly magnetized film even if the composition changes to this extent in the film thickness direction, it is more preferable that the composition change in the film thickness direction be as small as possible. The present invention was made in view of this situation, and is an apparatus for producing a Go--Cr perpendicularly magnetized film having a uniform composition not only in the length direction but also in the film thickness direction.

The present invention will be explained below using FIG.

FIG. 3 shows an example of a manufacturing apparatus according to the present invention, which differs from the apparatus shown in FIG. 2 in the arrangement of the evaporation source. In other words, in the apparatus shown in FIG. 2, the electron gun 1 for heating the Cr material 14 is located at
Although it is on the same side as the Cr material 14 with respect to the direction of movement of the substrate, in the apparatus of FIG.
The electron gun 17 for heating the material 14 is in the cylindrical can 2
is on the opposite side of the Cr material 14 with respect to the direction of movement of the substrate with respect to a vertical line 21 passing through the center of the substrate. The third evaporation source of Or
By arranging as shown in the figure, a C0-0r perpendicular magnetization film having a substantially uniform composition in the length direction and film thickness direction can be obtained. In fact, in a manufacturing apparatus in which the evaporation sources are arranged as shown in FIG.
A -Cr perpendicular magnetization film was produced. Analysis of the composition of the formed film revealed that the Cr concentration on the film surface was 23 wt%, Go-
The Cr concentration near the boundary between the Cr film and the substrate is 25 wt%
Co-(
An ir perpendicular magnetization film was obtained. Furthermore, since the film was produced by the Mihara vapor deposition method, the composition in the length direction was also uniform.

As described above, when using the apparatus according to the present invention, the reason why the composition becomes almost uniform in the film thickness direction is that Or evaporates due to sublimation.
It is thought that the density of evaporated atoms is highest in the direction close to the direction of the electron beam that heats and evaporates the Or material.

As described above, by performing vapor deposition using the manufacturing apparatus of the present invention, a Go-Or perpendicularly magnetized film having a substantially uniform composition in the length direction and film thickness direction can be obtained.

[Brief explanation of the drawing]

Figure 1 shows a manufacturing device in which CO and Or are evaporated from the same electron beam evaporation source, and Figure 2 shows a manufacturing system in which CO and Or are evaporated from separate electron beam evaporation sources to produce a magnetized film by Mihara evaporation. FIG. 3 is a diagram showing an example of the manufacturing apparatus according to the present invention. 1... Board, 2... Cylindrical can, 5
,13゜16... Crucible, 6...Co
-Or alloy material, 7...Electron gun, 8...Electron beam, 14...Or material, 16...C
O material, 17...Electron gun for Or material evaporation, 1
8...Electron gun for CO material evaporation. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3?

Claims (1)

[Claims] A magnetic layer containing Go and Or as main components and having an axis of easy magnetization perpendicular to the film surface is placed on a substrate that is moving along the circumferential side of a cylindrical can, and Go and Or are evaporated from separate electron beam evaporation sources. The apparatus is formed using the Mihara vapor deposition method, in which an electron gun for heating the Or material is oriented in a direction in which the Or material is heated relative to a vertical line passing through the center of the cylindrical can in the direction of movement of the substrate. An apparatus for manufacturing a perpendicular magnetic recording medium, characterized in that the media are on opposite sides.