JPS5994240A - Producing device of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a producing device of magnetic recording medium having the uniform magnetic characteristics of a magnetic recording thin film, by providing a masking plate having apertures of proper forms for each target between a substrate and plural targets. CONSTITUTION:A glass substrate 2 fixed to a substrate supporting turntable 1, an aperture masking plate 3, and targets 4 and 5 which discharge the sputtering atoms of Fe and Tb respectively are distributed in a vacuum room 6 filled with gaseous argon. For sizes of each part, d1=300mm., d2, d3=125mm.. h=90mm. and d4, d5=90mm. respectively, and the plate 3 is set at the position shown in the figure. The plate 3 contains two apertures, i.e., an aperture 3a for Fe is equal to a concentric circle of d5=155 and another aperture 3b for Tb has approximately a fan shape as shown in the figure. Then the prescribed volage is applied to both sides of the substrate 2 and targests 4 and 5 respectively in accordance with the form and size of each aperture. The argon particles are delivered against targets 4 and 5 to discharge Fe and Tb atoms. Thus a synthetic thin film containing 80 atom % Fe and 20 atom % Tb is formed on the rotary substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium manufacturing apparatus for manufacturing a disc-shaped magnetic recording medium.

In general, so-called magneto-optical recording, which performs magnetic recording using the heating effect of a minute spot of laser light, requires a recording medium that has a high recording density and is easy to write and read.

This type of recording medium includes rare earth iron garnet, chromium dioxide, rare earth/transition metal alloys (e.g., cadrinium/cobalt alloy (Gd/CO), cadrinium/
Iron alloy (G(1, Fθ), terbium-iron alloy (Tb,
F'θ), manganese-terbium-bismuth alloy (Mn
・Tb @Bi ), etc.), manganese-bismuth alloy (
Various examples include Mn 11 B i ), and manganese-copper O-bismuth alloy (Mn 1 B i ).

Considering the characteristics of each of these media, first of all, the rare earth iron garnet recording medium is formed by growing crystals on a single crystal substrate by liquid phase epitaxial method, but it cannot be made into a large area. However, since the substrate itself is a thin single-crystal plate, it is easily broken, which makes it difficult to use as a practical large-capacity memory medium.

Next, as is well known, chromium dioxide recording media are manufactured by applying needle-shaped chromium dioxide particles to a flexible substrate such as polyethylene terephthalate using a binder, and are used for magnetic recording and video recording. It is used as a magnetic tape for (VTR) applications. Chromium dioxide is a ferromagnetic material, and its Curie temperature is as low as 120-130C (
Heating by laser spot h''--it is easy to use and has a relatively large magneto-optic effect, making it suitable for optically reading out stored magnetic information, and therefore can be used as a magneto-optical recording medium. , and also, for example, 3
It can also be formed as a thin film on a circular substrate (glass, plastic, etc.) with a diameter of about 0 ctn. However, chromium dioxide recording media require a binder bt for applying chromium dioxide to a substrate, and it is considered difficult to achieve a storage density comparable to that of an optical video disc.

Compared to the above two, rare earth/transition metal alloy, Mn5B
i, Mn*0usBi can be formed into a film by vacuum evaporation or sputtering, and it has been demonstrated that the Curie temperature, compensation temperature, and magneto-optic effect can be controlled by the composition, and that it can also have a very high storage density. However, the magnetic properties that determine the memory properties are sensitive to composition, and it has been difficult to form a layer with uniform properties over an area of 30c1n diameter using conventional vacuum deposition or sputtering. In addition, rare earth
When producing a thin film with an amorphous structure such as a transition metal alloy, it has already been found that sputtering produces a more homogeneous amorphous film with less microscopic graininess than vacuum deposition.

The present invention relates to the above-mentioned rare earth/transition metal alloy, Mn/Bi,
To provide a magnetic recording medium device for producing a magnetic recording medium having uniform magnetic properties over a wide area, which was developed to solve the problems of producing magnetic recording media using alloys such as Mn and OuaBi. With the goal.

Therefore, in the present invention, a multi-target simultaneous sputtering method (multi-target method, a method in which sputtering is performed from a plurality of targets (3) if, and the number of targets is usually 2 to 3) is used. In a magnetic recording medium manufacturing apparatus that deposits a target material sputtered from a target onto a rotating substrate provided facing the plurality of targets, and forms a magnetic recording thin film (a thin film of a multi-element material) on the substrate. By providing a shielding plate having an appropriately shaped opening for each target between the plurality of targets and the substrate, the magnetic properties of the magnetic recording thin film are made uniform.

Hereinafter, one embodiment of the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 and FIG. 2 are a plan view and a front view, respectively, showing an embodiment of a magnetic recording medium manufacturing apparatus according to the present invention.

A glass substrate 2 fixed to a substrate support rotary table 1 to which a thin film is attached, an aperture shielding plate 3, a target 4 for emitting sputtered atoms of Fθ, and a target 5 for emitting sputtered atoms of Tl) are shown in Fig. 1(4). and as shown in FIG. 2, it is placed in a vacuum chamber 6 filled with, for example, argon gas.

Here, the diameter d of the substrate 2 is 300 cm, the target 4,
The diameter d2edB of 5 is 125IIll111, and the distance between substrate 2 and targets 4 and 5 is 90mm, substrate 20
The distance d between the center of rotation and the center of targets 4 and 5, (1
, are each 90 m, and the aperture shielding plate 3 is disposed between the substrate 2 and the targets 4 and 5 (see FIG. 2).

Further, as shown in FIGS. 1 and 3, the shielding plate 3 is provided with two openings, and the first opening 3a for Pe is a concentric circle whose center coincides with the central axis of the target 4. Its diameter d6 is 155. The second aperture 3b for Ttl has a concentric circle whose center coincides with the central axis of the target 5 (diameter d, 155 m), and the center of the aperture shielding plate 3 (a position on the aperture shielding plate 3 facing the substrate rotation center). It has a substantially fan shape surrounded by two tangent lines drawn from C to the circumference of the target 50 projected onto the aperture shielding plate 3.

Based on the shape and dimensions described above, a predetermined voltage is applied to the substrate 2 side and the targets 4 and 5, and cationized argon particles collide with the targets 4 and 5 to release Fθ atoms and Tb atoms. , Rotating through board 21'CF 880
! When an alloy thin film consisting of 20 atomic percent of Tb and 20 atomic percent of Tb was prepared, it was found that the diameter of the substrate 2 was 110+m or more.
A thin film formed within the range of 00wm or less has a coercive force of 1.2±o, OA KO13C fluctuation rate of 2.5% above), Curie temperature of 103.5±0.5C, and a film thickness of 0.3% of above. 1. A magnetic recording medium with excellent uniformity could be produced.

It is easy to believe that the reason why it has become possible to produce a magnetic recording medium with uniform characteristics over a large area is due to the shape of the aperture in the aperture shielding plate 3, especially the substantially fan-shaped second aperture C13b. It will be done.

In this embodiment, an apparatus for producing a magnetic recording medium made of two elements has been described, but it is also possible to produce a magnetic recording medium made of three or more elements.

In that case, the first target is a target that releases the alloy, and the second target is a target that releases additives for the alloy. Alternatively, the first target is a so-called composite target (a target of a pure single element, with multiple small pieces of an element different from that element placed on top of the target)
The present invention can also be used as a target for releasing Y additives.

Further, as shown in FIG. 4, the openings 3a, 3 of the opening shielding plate 3
b4 Furthermore, by shielding with other additional shielding plates 7 and 8, the characteristics (coercive force, coercive force,
It is also possible to control the squareness (squareness, etc.).

As explained above, according to the present invention, it is possible to produce an alloy thin film having uniform magnetic properties over a large area.

Note that the shape of the opening of the shielding plate is not limited to this example, and may be any suitable shape in view of the type of alloy and the properties of the alloy. However, it is effective to make at least one of the plurality of openings into a substantially sector-shaped shape whose opening width increases in accordance with the distance from the center of the shielding plate (7).

[Brief explanation of drawings]

FIG. 1 is a plan view of a magnetic recording medium manufacturing apparatus according to the present invention;
2 is a front view of FIG. 1, FIG. 3 is a view of the opening of the aperture shielding plate according to the invention, and FIG. 4 is a view of the aperture shielding plate additionally shielded. ■...Substrate support rotary table, 2...Glass substrate, 3...
- Opening shielding plate, 3a, 3b... opening, 4, 5... target, 6... vacuum chamber, 7, 8... shielding plate. (8) Figure 1 Figure 2

Claims (2)

[Claims] (1) In a magnetic recording medium manufacturing apparatus that deposits a target material sputtered from a plurality of targets onto a rotating substrate provided facing the plurality of targets, and forms a magnetic recording thin film on the substrate, the 4. A magnetic recording medium manufacturing apparatus characterized in that the magnetic properties of the magnetic recording thin film are made uniform by providing a shielding plate having an appropriately shaped opening for each target between a plurality of targets and a substrate. (2) At least one of the shapes of the openings of the shielding plate is approximately fan-shaped, and the width of the opening increases in accordance with the distance from the position on the shielding plate facing the rotation center of the substrate. A magnetic recording medium manufacturing apparatus according to claim (1).