JPS6288131A - Magnetic disk - Google Patents

Abstract

PURPOSE:To increase remarkably a life of a disk by providing an intermediate supporting layer consisting of an amorphous silicon and a silicon compound, between a magnetic layer and a carbon film. CONSTITUTION:A pressure in each chamber 1c, 1d is dropped to a prescribed pressure by holding substrates 3a, 3b by substrate electrodes 2a, 2b, respectively, and opening exhaust valves 10a, 10b, and also an Ar gas is led into each chamber 1c, 1d from Ar gas use leading-in pipes 8a, 8b by opening Ar gas flow rate adjusting valves 9a, 9b, and thereafter, the inside of each chamber 1c, 1d is set to a prescribed sputter pressure by adjusting the closing quantity of the exhaust valves 10a, 10b. Subsequently, when a DC voltage 11a is impressed between a target voltage 7a and the substrate electrode 2a, and an RF voltage 11b is impressed between the electrode 7a and the substrate electrode 2b, a glow discharge is generated between each electrode 7a, 2a, 7b and 2b, an intermediate layer target 4 and a carbon target 5 are brought to sputtering, and a thin film of a prescribed film thickness is formed on the substrates 3a, 3b. In this way, the wear resistance becomes extremely good.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic disk, and particularly to a thin film type high-density magnetic recording medium in which an amorphous carbon film is formed on a magnetic thin film.

[Background of the invention]

In recent years, in the field of magnetic recording, there has been a desire for smaller recording/reproducing devices and for the emergence of recording media that can perform high-density recording.

In response to this, instead of the conventional coating medium of γ-Fe2O3, γ-Fe20. , a magnetic medium made of Co--Cr formed by sputtering has been proposed.

In magnetic disks, these media are used to record and
In the reproduction method, a magnetic head and a magnetic recording medium are set in contact with each other, and when the magnetic recording medium is rotated, an air layer is generated between the i-air head and the magnetic recording medium, which causes the head to levitate. A so-called contact start-stop method (hereinafter referred to as C8S) is implemented.

However, in the above method, the magnetic recording medium is damaged due to sliding between the magnetic head and the magnetic recording medium, so to prevent this, a protective film or a lubricating film must be provided on the magnetic recording medium.

In addition, as the gap between the magnetic head and the magnetic recording medium becomes larger, it will lead to a decrease in output. Therefore, in order to achieve high recording density, the physical properties of the protective film or lubricant film must be strong, free of pinholes, and extremely polar. It needs to be thin and have self-lubricating properties.

Therefore, various methods of forming a protective film on the surface of a magnetic recording medium have been proposed. For example, a method of forming a metal oxide such as SiO2 on the surface of a metal magnetic material, Sj,
There are methods of forming carbides and nitrides such as Tu by sputtering, ion blasting, etc., and methods of forming a carbon thin film on the surface of the magnetic recording medium.

In addition, as a method of forming lubricating oil, higher fatty acids can be used to form a lubricating oil with a relatively small coefficient of friction.

There is a method of forming a wet lubricant thin film using silicone oil, fluorine oil, etc.

These protective films and lubricating films are used individually on the surface of the magnetic thin film medium, or a lubricating film is further provided on the protective film.

However, metal oxides, nitrides, carbides, etc. have high friction coefficients and do not have sufficient wear resistance, so it is common to use a protective film and a lubricating film together.

However, the lubricating film does not have sufficient affinity with the magnetic recording medium or the protective film and cannot sufficiently withstand sliding with the magnetic head, and in the case of surface C8S, there is a drawback that it is prone to magnetic adhesion.

Further, in the case of a carbon thin film, it has a drawback that it easily peels off because its adhesion to a magnetic surface such as γ-Fe=03 is low.

Regarding thin film magnetic disks, for example, J-Appl Phys 55
(6) 15 March 1984 Vacuum-deposited thin-me film disc by E-M Rossi
tal filmdisk) ・Industrial materials Vow-, 3
3 No. 4 April (Aprj, ), 1985, "Manufacture of Cobalt-Nickel Metal Thin Film Magnetic Disks" by Hitachi Metals.

Published in Nippon Denki's ``Protective Film for Plated Magnetic Disks'' by Yanagisawa at the 2nd RIKEN Symposium on Creation of New Surfaces and Characteristic Evaluation.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk which solves the above-mentioned conventional problems and greatly improves the life of the disk.

[Summary of the invention]

In order to achieve the above object, the present invention provides a protective film or lubricant that is strong, has no pinholes, is ultra-thin, has self-lubricating properties, and has strong adhesion to the magnetic layer surface and is difficult to peel off. A thin film made by sputtering carbon was selected because the magnetic head would not stick to the surface of the magnetic disk. This is because sputtering uses physical adsorption, which is advantageous in terms of increasing adhesion, and because the distance between the magnetic head and magnetic disk during C8S, that is, the head spacing, is small, the film thickness after film formation is uniform. This is because sputtering is easy in this respect. In addition, carbon film is considered to be effective because the head has non-adhesive properties and self-lubricating properties. However, on the other hand, γ-Fe, 01
It was also found that the adhesion to the surface of the magnetic layer was poor and film peeling was likely to occur. Therefore, in the present invention, we investigated forming a metal film, an organic polymer film, an inorganic compound film, etc. as an intermediate support layer between the magnetic layer and the carbon film, and found that Si compounds and amorphous silicon have a strong adhesion. We have found that this is the most effective method for improvement.

The sputtering method that can be used in the present invention is CD type R.
F sputtering, PM type RF sputtering, 1]C
Sputtering, DC magnetron sputtering,
Can be used with both intermediate support layer and carbon layer, especially P M type R
F sputtering and DO magnetron sputtering are preferred, and a bias may be applied to the substrate.

Further, examples of the intermediate support layer that can be used in the present invention include amorphous silicon, SiC, Si3N4. SiBr
4°5i02+silicone resin, etc., and reactive sputtering or the like may be used when forming these intermediate support layers. Among these middle supporters, especially
Amorphous silicon, SiC, and silicone resin are preferred.

Further, in the magnetic disk of the present invention, it is preferable that the intermediate support layer and the carbon layer are formed continuously in a vacuum, but if the intermediate support layer and the carbon layer are to be once exposed to the atmosphere.

Surface cleaning such as sputter etching may be performed.

[Embodiments of the invention]

Below, a diagram showing an embodiment of the present invention will be explained.

The figure is an explanatory diagram showing main parts of a sputtering apparatus according to the present invention. As shown in the figure, the inside of the chamber 1 is divided into two chambers 1c and ld by a partition wall 1b having a through hole 1a,
In each chamber 1c, ld there is a substrate 3a in the upper part,
A target electrode 7a holds an intermediate layer target 4 or a carbon target 5 and magnets 6a, 6b at positions facing the substrates 3a, 3b below.

7b is installed and these target electrodes 7a and '7b are RF
Connected to constant power supply or DC'f4f, pressure 11a, llb. In addition, each chamber 1c, ld includes inlet pipes 8a, 8b for Ar gas having a purity of 99.99%, which hold Ar gas flow rate adjustment valves 9a, 9b, and exhaust pipes 10c, 10d, which hold exhaust valves 10a, 10b. It is installed.

Since the sputtering apparatus according to the present invention has the above-described configuration, the substrays 1-3a and 3b are held on the substrate electrodes 2a and 2b, respectively, the exhaust valves 10a and 10b are opened, and each chamber 1c is opened by the exhaust pipes 10c and 10d. , ld
At the same time, the pressure in
Ar is introduced into each chamber 1c and ld from the gas introduction pipes 8a and 8b.
After the gas is introduced, the amount by which the exhaust valves 10a and 10b are closed is adjusted to set the inside of each chamber 1c and ld to a predetermined sputtering pressure (for example, l x 10-2 Torr).

Next, a DC voltage is applied between the target electrode 7a and the substrate electrode 2a.
Applying voltage 11a, target electrode 7a and substrate electrode 2
When the RF voltage 11b is applied between the electrodes 7a and b,
Glow discharge occurs between 2a, 7b, and 2b, and the intermediate layer target 4 and carbon target 5 are sputtered to form a thin film of a predetermined thickness on the substrates 3a, 3b.

[Example 1] After forming an alumite layer on an aluminum alloy substrate by anodizing, amorphous silicon was formed using the sputtering apparatus shown in the figure above using a magnetic recording medium on which a γ-Fe, 03 magnetic layer was formed. Then, carbon films were formed to a thickness of 50 and 200, respectively. The film formation conditions at this time were: for amorphous silicon, the power was 750 V, 5 A, and the gas pressure was 15 mTorr; for the carbon film, the power was 1.5 KW, and the gas pressure was 10 rn.
Torr, and the substrate temperature was both 200°C.

Note that in Examples 2 to 4 described below, the conditions for forming the carbon film are the same as in Example 1.

[Example 2] The magnetic recording medium in Example 2 is the same as that in Example 1, and uses the sputtering apparatus shown in the figure.

Further, after forming SiC as an intermediate support layer, a carbon film was formed with a thickness of 100 layers and 300 layers, respectively.

Furthermore, the above SiC formation conditions include a power of 600V.
50 A, gas pressure 10 m T Orr + substrate temperature 250°C.

[Example 3] The magnetic recording medium in Example 3 is the same as that in Example 1, and uses the sputtering apparatus shown in the figure.

Further, a silicone resin was sputtered to form an intermediate support layer. However, PM type RF is used for insulators.

Furthermore, the target is coated with a silicone resin material and then hardened.

The film-forming conditions were a power of 600 W, a gas pressure of 3 mTorr, and a film thickness of 50 for the silicone resin layer and 20 for the carbon layer.
The number of participants was 0, and the substrate temperature was 200°C.

[Example 4] Example 4 was produced in the same manner as in Example 1 except that Si and N4 were used for the intermediate support layer.

The above 5i3N4(7) film formation conditions are power: 600V, 3A
, the gas pressure was 7 mTo, and the substrate temperature was 250°C.

Comparative Example 1: On the same magnetic recording medium as in Example 1, in which no intermediate support layer or carbon film was formed, a 500 mm thick S was formed by the following method.
iO was formed.

That is, it was formed using a CD type RF sputtering method at a power of 1.5 KW and a gas pressure of 15 mTorr.

Further, the substrate temperature was 200°C.

Comparative Example 2 Perfluoroalkyl ether (Kry tox 143C8Du P
Ont) was spin coated as a 0.01% Freon solution and then heat treated at 120° C./I Hr.

The abrasion resistance of the magnetic recording media of Examples 1, 2, 3.4 and Comparative Examples 1 and 2 was measured using a magnetic recording device at C8.
S, investigate the output fluctuation after 30,000 times, and then increase the adhesive force of the magnetic head to 50% R) (.

Measurements were taken after leaving it for 120 hours. Iil at this time
The determination method was to leave the magnetic head in contact with the magnetic recording medium, and then pull it in the horizontal direction to determine the force required to move the magnetic head.

Further, the adhesion force required for the intermediate support layer was measured by a beer test, and the adhesion force determined thereby was taken as the adhesion force between the intermediate support layer and the carbon layer.

The above results are summarized in the following table.

〔Effect of the invention〕

According to the present invention, the adhesive force of the magnetic head can be suppressed to 3 g or less, and the abrasion resistance is also much better than that of conventional methods. It is suitable.

[Brief explanation of drawings]

A'/box is an explanatory diagram showing the main parts of the sputtering apparatus according to the present invention. 1... Chamber, 2a, 2b... Substrate electrode, 3
a, 3b...substrate, 4...intermediate support layer target, 5...carbon target, 6a, 6
b...Magnet, 7a, 7b...Target electrode,
8a v 8b ・= Ar gas introduction pipe, 9a,
9b...Ar gas flow rate adjustment valve, 10a, 10b.
...Exhaust valve, 10c. 10d...Exhaust pipe. Agent Patent attorney Tadashi Akimoto Younger brother 1 Figure

Claims (1)

[Claims] 1. A magnetic layer formed by sputtering is provided on a support, an intermediate support layer is provided on this magnetic layer to protect the magnetic layer, and a solid lubricant layer is provided on this intermediate support layer. 1. A magnetic disk having a carbon layer as a magnetic disk, wherein the intermediate support layer is made of amorphous silicon or a silicon compound. 2. The magnetic disk according to claim 1, wherein the magnetic layer is made of γ-Fe_2O_3. 3. The magnetic disk according to claim 1, wherein the intermediate support layer and the carbon layer are composed of amorphous thin films formed by sputtering.