JPS6295739A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a smooth surface by applying a high-frequency bias voltage to a substrate and selectively resputtering a film grown on the projecting parts of the substrate in the stage of forming a high permeability magnetic film on the substrate by a sputtering method. CONSTITUTION:Ar is introduced into a vessel 8 to maintain a prescribed vacuum degree therein. A high-frequency voltage is impressed from a power source 3 to a target 1 to generated plasma and a high permeability Fe-Ni alloy film is formed on the Al alloy substrate 4 formed by subjecting the surface to an alumite treatment from Fe-Ni 2. Electrons from the plasma are accumulated in the substrate and the same state as the state in which a negative bias voltage is impressed is attained when the high-frequency voltage is impressed from a power source 6 to a substrate holder 5. The Ar<+> ions in the plasma arrive at the substrate and balance near the substrate 4. The average negative DC bias is thus determined. The film grown on the projecting parts of the substrate is selectively resputtered by the Ar<+> ions arriving at the substrate, by which the surface is smoothed and the vertical magnetic recording medium having a good surface characteristic is obtd. The spacing quantity between a magnetic head and the medium is decreased and the substantial reproduction voltage is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic recording medium suitable for perpendicular recording.

[Conventional technology]

Perpendicular recording is an example of magnetic recording with excellent short wavelength recording characteristics. This 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, and therefore, the shorter the signal wavelength, the smaller the demagnetizing field within the medium, resulting in superior reproduction output. Perpendicular recording media are currently made by using a high-permeability magnetic thin film such as permalloy on a non-magnetic substrate.

Many materials have been developed in which a magnetic layer containing Cr t- as the main component and having an axis of easy magnetization in the perpendicular direction is formed by sputtering or the like.

However, in magnetic recording, as in large-capacity magnetic disk drives for electronic computers, magnetic disks are rotated at high speed in order to increase the data transfer rate, and magnetic heads are sometimes used by floating a certain amount of spacing above the medium. In many cases, when the amount of spacing increases, the intensity of the head magnetic field applied to the medium during recording weakens, and its distribution widens, making it difficult to saturate the medium or leave steep magnetic transitions on the medium. During reproduction, the amount of magnetic flux interlinking with the windings of the reproducing head decreases, resulting in a decrease in the reproducing voltage. Therefore, in order to obtain good recording and reproducing characteristics, it is desirable that the spacing between the head and the medium be small.

In order to minimize the spacing between the head and the medium, it is necessary to improve the surface properties of the recording medium, and to devise ways to improve the shape of the tip of the head and the lubrication between the head and the medium. It is.

[Problem that the invention seeks to solve]

However, the surface quality of magnetic recording media, especially magnetic disk substrates manufactured using conventional methods, is achieved by polishing an aluminum alloy substrate that has been alumite-treated, or by applying N1-P plating and then polishing. However, the surface finish is not necessarily sufficient due to protrusions, etc., and in order to obtain stable levitation, the spacing amount should be 0.25
0.3-m, and there was a problem that a sufficient reproduction voltage could not be obtained.

This invention was made to solve the above-mentioned problems, and provides a magnetic recording medium in which the perpendicular magnetic recording medium has good surface properties and the spacing between the magnetic head and the medium is small. The purpose is to provide a manufacturing method for.

[Means for solving problems]

A method for manufacturing a magnetic recording medium according to the present invention is such that a high permeability magnetic film is formed while a high frequency bias voltage is applied to a substrate.

[Effect]

In this invention, when forming a high permeability magnetic film on a substrate by sputtering, by applying a high frequency bias voltage to the substrate, the film grown on the protrusions of the substrate is selectively sputtered again and the surface is smoothed. Ru.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

The drawing is a cross-sectional configuration diagram showing a sputtering apparatus used in a method of manufacturing a magnetic recording medium according to an embodiment of the present invention. il target, in this case F
e-Ni target), (3) is a sputtering power source, (4) is an aluminum alloy substrate with an alumite treatment on the surface, that is, the base, (5) is a conductive substrate holder that also serves as an electrode, (6) is a high frequency power source, (7) is a shield plate, (8) is a vacuum chamber, (
9) is a shutter, and σQ is a second target for forming a magnetic film having an axis of easy magnetization perpendicular to the film surface of the high permeability magnetic film, in this case a Co--Cr target.

Next, the operation will be explained.

After evacuating the inside of the vacuum chamber (8) to a level of 10-7 Torr, pure argon (Ar) gas is introduced to maintain a constant degree of vacuum (for example, 1 to 2 X 10 Torr), and the sputtering power source (3) is used to connect the target electrode. When a negative DC high voltage or high frequency voltage is applied to (1), plasma is generated and Fe
A high permeability magnetic film, that is, a high permeability Fe--Ni alloy film is grown on the aluminum alloy substrate (4) whose surface has been subjected to an alumite treatment by sputtering from the -Ni target (2).

At this time, when a high frequency voltage is applied to the conductive substrate holder (also used as an electrode) (5) by a high frequency power source (6), only electrons from the plasma arrive at the substrate (4) at first, and the electrons are gradually accumulated. As a result, the substrate (4) will be in the same state as if a negative bias voltage had been applied, and as a result, it will be difficult for electrons in the plasma to reach the substrate (4) due to the repulsion caused by the bias. . On the other hand, Ar+ ions in the plasma are accelerated by a negative bias and arrive at the substrate (4).

As a result, when the amount of electrons and ions arriving at the substrate (4)K during the - period is equal to about 9, an equilibrium state is reached near the substrate (4), and an average negative DC bias is established. The induced DC bias voltage is a high frequency power supply (6)
approximately equal to half the peak-to-peak voltage applied by

At this point, the Ar+ ions that have arrived at the substrate selectively re-sputter the film that has grown on the protrusions of the substrate, smoothing the surface and providing good surface properties.

Note that if the value of the DC bias induced in the substrate (4) is equal to or larger than the voltage applied to the target,
Since growth of the magnetic film will not occur, it must be kept lower than that.

In this way, a high permeability magnetic film, in this case Fe-N
After forming the i alloy film, the Co-Cr target σC
Co-Cr t-sputtering is performed to form a magnetic film with an axis of easy magnetization perpendicular to the surface of the high magnetic permeability magnetic film, thereby producing a perpendicular magnetic recording disk with good surface properties.

The disks created in this way have a distance between 0.054 m and 0.1 m, where stable levitation cannot be obtained with conventional disks.
It was possible to drive with a small spacing of μm.

In addition, in the above example, Fe-N was used as the high magnetic permeability material.
i alloy was used, but MO-Fe-Ni alloy, Mo-C
It may also be an amorphous alloy such as u-Fe-Ni alloy or Co-Ti.

〔Effect of the invention〕

As described above, according to the present invention, since a high permeability magnetic film is formed while a high frequency bias voltage is applied to the substrate, the surface properties of the perpendicular magnetic recording medium are good and the amount of cisbasing is reduced. This has the effect that it is possible to obtain a method of manufacturing a magnetic recording medium that can obtain a sufficient reproduction voltage.

[Brief explanation of drawings]

The figure is a cross-sectional configuration diagram showing a sputtering apparatus used in a method of manufacturing a magnetic recording medium according to an embodiment of the present invention. (1)...Target electrode, (2)...Fe-Ni
Target, (3)... Sputtering power supply, (4)...
Aluminum alloy substrate, (5)... conductive substrate holder, (
6)...High frequency power supply, (7)...Shield plate, (3
)...Vacuum chamber, (9)...Shutter, α0...
co-Cr target

Claims (2)

[Claims] (1) A high permeability magnetic film is formed on a substrate by sputtering, and a magnetic film having an axis of easy magnetization perpendicular to the film surface is formed on the high permeability magnetic film, in which A method of manufacturing a magnetic recording medium, characterized in that a high permeability magnetic film is formed while a high frequency bias voltage is applied to the magnetic recording medium. (2) Manufacturing a magnetic recording medium according to claim 1, wherein the magnetic film having an axis of easy magnetization in a direction perpendicular to the film surface of the high magnetic permeability magnetic film contains Co and Cr as main components. Method.