JPH0319134A - Production of magnetic disk - Google Patents

Abstract

PURPOSE:To surely protect a magnetic recording medium film and to obtain the magnetic disk having high reliability by oxidizing the surface part of the magnetic recording medium layer formed on a substrate by the plasma formed in a gaseous Ar atmosphere contg. oxygen to form an oxide film and coating the oxide film with a lubricating film. CONSTITUTION:The surface part of the magnetic recording medium layer 3 formed on the substrate 1 is oxidized by the plasma formed in the gaseous Ar atmosphere contg. the oxygen, by which the oxide film 4 is formed. This oxide film 4 acts as the protective film of the magnetic recording medium layer 3 and can lessen the spacing loss of a magnetic head and the magnetic recording medium layer 3. The magnetic recording medium film 3 is surely protected in this way and the magnetic disk of the high reliability which obviates the spreading of the effective spacing between the magnetic head and the magnetic recording medium film 3 is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic disk that is used as a recording medium in a magnetic recording device and has significantly improved spacing loss. [Background Art] In recent years, the importance of external storage devices such as magnetic disk drives in computer systems has increased, and the demand for high recording densities has been increasing. A magnetic disk drive consists of a main structure of a recording/reproducing head and a magnetic disk.The magnetic disk rotates at high speed, and the recording/reproducing head, that is, the magnetic head, floats a minute distance above the magnetic disk. In order to increase the recording density and performance of M1 disks, it is necessary to make the magnetic recording medium thinner, more uniform, improve the magnetic properties (improvement of coercive force and squareness ratio), and lower the magnetic head. Examples include levitation. Up until now, magnetic disks have been manufactured by coating a mixture of polymeric materials such as binders and T-FezJ magnetic recording media particles. This method has limitations in making the magnetic recording medium thinner and more uniform. For this reason, recently, magnetic recording media have been deposited as a continuous thin film on the substrate using methods such as sputtering. Currently, magnetic disk remounting uses a contact start/stop (CSS) method in which the magnetic disk and magnetic head come into contact with each other when starting and stopping. do. The frictional force generated between the magnetic head and the magnetic disk in this contact friction state causes friction between the magnetic head and the surface of the magnetic disk, and may eventually cause scratches on the magnetic head and the magnetic recording medium film. When a continuous thin film is used as a magnetic recording medium, even a slight scratch will cause the recording medium to become defective. This leads to loss of signal. This is a serious problem concerning the reliability of magnetic disk devices as external storage devices. Therefore, on the surface of the magnetic disk,
In order to protect the magnetic recording medium from contact friction and contact damage between the magnetic head and the magnetic recording medium, SiOxlI! ,
It has been proposed to provide a protective film such as a carbon film or ^1zOslI (for example, Akio Tago et al., Abstracts of the 8th Japanese Society of Applied Magnetics, Academic Lectures (1984), p. 222; Yoshihiro Kimachi et al., 1988). Proceedings of the Annual National Conference of the Institute of Electronics and Communication Engineers (1986), page I-166; Hiroyasu Karimoto et al., Proceedings of the 30th Spring Research Presentation of the Japan Society of Lubrication (1986)
6) Published on pages 1, 4, etc. ). Furthermore, when the magnetic recording medium is metal, this protective film also serves to prevent corrosion of the metal film. [Problem to be solved by the invention] The protection provided in this way! The film has a thickness of several hundred people on the magnetic recording media film. On the other hand, the distance between magnetic heads has been reduced to about 2,000 people due to lower flying heights, which prevents a drop in playback output and achieves high recording density. However, the magnetic recording medium film does not hold! If one film is provided, its mere presence will cause a spacing loss of several hundred, which increases the distance between the magnetic head and the magnetic recording medium, causing a problem in that the reproduction output decreases. This invention was made in order to solve the above-mentioned problems, and it is possible to reliably protect the magnetic recording medium film without increasing the effective distance between the magnetic head and the magnetic recording medium film. The purpose is to obtain a highly reliable manufacturing method for magnetic disks. [Means for Solving the Problem] As a result of extensive research in order to achieve the above-mentioned objectives, the inventors discovered that a plasma formed by a plasma generated in an oxygen-containing Ar gas atmosphere was discovered. The inventors have discovered that an oxide film, or an oxide film formed by reactive sputtering in an oxygen-containing Ar gas atmosphere, is effective, and have completed the present invention. That is, the first invention forms an oxide film by oxidizing the surface portion of a magnetic recording medium layer formed on a substrate using plasma grown in an oxygen-containing Ar gas atmosphere. It is. This second invention forms a magnetic recording medium layer on a substrate by sputtering in an Ar gas atmosphere, mixes oxygen into the Ar gas, and forms an oxide film on the surface of the magnetic recording medium layer by reactive sputtering. It is something.
[Function] According to the first invention, the surface portion of the magnetic recording medium layer on the substrate is oxidized by plasma generated in an oxygen-containing Ar gas atmosphere to form an oxide. However, this oxidation progresses from the surface of the magnetic recording medium layer to the deeper part. Further, according to the second invention, the shape of the magnetic recording medium layer on the substrate and the shape of the oxide film on the magnetic recording medium layer are such that oxygen is mixed into the atmosphere from the Ar gas atmosphere. Not only can this be achieved through a series of operations, but the thickness of the oxide film can also be easily controlled by changing the reactive sputtering conditions. The magnetic disk obtained by this invention has an extremely thin oxide film formed on the surface of the magnetic recording medium layer, and this oxide film acts as a protective film for the magnetic recording medium layer, and is more effective than conventional protective films. Spacing loss between the magnetic head and the magnetic recording medium layer can be extremely reduced. [Example] Example 1 An example of the present invention will be described below with reference to the drawings. No.l
The figures are partially enlarged cross-sectional views sequentially showing a part of the process of manufacturing a magnetic disk according to an embodiment of the present invention. Geological layer, (3) is the magnetic recording medium layer, (4) is the oxide film,
5》 is a lubricating film. Ni on the surface of the AI-Mg alloy substrate
- Using a tape polisher, apply ramping tape WA#600 to a substrate on which a P plating film has been formed and which has been mirror-finished.
Texture processing was performed under the following conditions: 0, pressing force 1-, substrate rotation speed 200 rpm, and tape feed rate 20 W/sin. As a result, an AI-Mg alloy substrate (1) with an Rmax of about 500 was obtained. Cr on the above substrate (1) under 5 argon pressure
A non-magnetic material base layer (2) having a thickness of 1000 mm was formed by sputtering under the following conditions: Next, the substrate +1) provided with the underlayer (2) was placed in a vacuum bell jar (not shown) of a sputtering device, and
Using o-Ni alloy target (weight ratio 70:30), argon pressure 5 x 10 mTorr substrate temperature 70
A magnetic recording medium layer (3) with a film thickness of 500 mm was obtained by sputtering at 300 W/3 inch 4φ at a power of 300 W/4φ.
FIG. 1(al): After film formation, the magnetic disk was placed in a plasma of Ar gas containing oxygen at 10 mTorr for 30 seconds to form an oxide film (4) on the surface of the magnetic recording medium layer (first Figure (bl). Liquid lubricant (K) after this surface treatment
A 2% solution (solvent: Freon 1) of RYTOX 1 5 7/M (trade name manufactured by DuPont) was spin-coated to form a lubricant (5) as shown in Figure 1 (Cl). Example 2 In the same manner as in Example 1, a magnetic disk (mountain in Figure 1) was prototyped. On this disk, apply a silane casing agent (KBM603).
: A 5% solution (solvent: IPA) of Shin-Etsu Chemical's product name, aminosilane type was spin-coated, and then a liquid lubricant (K
A 2% solution of RYTOX 157 FS/M (trade name manufactured by DuPont) (solvent: Freon 113) was spin coated. Embodiment 3 FIG. 2 is a partially enlarged sectional view sequentially showing a part of the process of manufacturing a magnetic disk according to another embodiment of the present invention. In the figure, symbols (1) to (5) have been explained in FIG. 1, so their description will be omitted. Cr was applied to the AtMg alloy substrate (1) obtained in Example 1 with an Rmax of about 500 people under an argon pressure of 5 x 10 mTorr.
A non-magnetic material base layer (2) having a thickness of 100 mm was formed by sputtering at a substrate temperature of 100° C. and a power of 300 W/3 inches 4φ (Fig. 2). Next, the substrate (1) provided with the underlayer (2) was placed in a vacuum bell jar (not shown) of a sputtering device, and a Go-Ni alloy target (weight ratio 70:30) was placed under an argon pressure of 5X.
10mTorr sSubstrate temperature 70℃, power 300
A magnetic recording medium layer (3) having a film thickness of 500 nm was obtained by sputtering with W/3 inches and 4φ (Fig. 2(b)). Oxygen was introduced near the end of this certain film. The oxygen flow rate was set to 20% of the argon flow rate, and the spanner pressure was l.
An oxide film (4) was formed on the surface of the magnetic recording medium layer (3) by reactive sputtering at QmTorr (
Figure 2(c)). 7i! After the film is finished, liquid lubricant (KRY
A 2% solution (solvent: Freon 1) 3) of TOX 1 5 7 FS/M (trade name manufactured by DuPont) was spin-coated to form a lubricant lI (51 (Fig. 2 (dl)). Example 4 A magnetic disk (Fig. 2 <<C>>) was prepared in the same manner as in Example 3.
We made a prototype. A silane camping agent (KBM601) is placed on this disk.
A 5% solution (solvent: IPA) of Shin-Etsu Chemical's product name, ξ-nosilane series) was spin-coated, and then a liquid lubricant (K
A 2% solution of RYTOX 1 5 7 FS/M (trade name manufactured by DuPont) (fJ medium: Freon 1) 3) was spin-coated. Comparative Example 1 AtM. of about Rmax 500 people obtained in Example 1. Base Cr film on alloy substrate, CoNi as magnetic recording medium
was deposited by sputtering. A protective film of Cr and carbon was formed on this magnetic recording medium layer by sputtering according to a known method. This protective film had a thickness of 600 including the underlying Cr film. Comparative Example 2 A base Cr film was formed on the AtMg alloy substrate obtained in Example 1 with an Rmax of about 500, and a Co-Ni film was used as a magnetic recording medium.
was deposited by sputtering. Thereafter, a 2% solution (solvent: Freon 1)3) of a liquid lubricant (KRYTOX 1 5 7 FS/M: trade name manufactured by DuPont)3) was spin coated. The reproduction output of the magnetic disks according to Examples 1, 2, 3, and 4 and Comparative Examples 1 and 2 was investigated. Table 1 shows the normalized output with the playback output of Comparative Example 2 set at 1. Table 1 As is clear from the above results, when the conventional protection layer (Cr and carbon) is provided on the magnetic medium film, a decrease in the reproduction output is observed. Examples 1, 2, 3, 4
, the magnetic disks according to Comparative Examples 1 and 2 were heated at a temperature of 60° C. and a humidity of 90% R. H. Table 2 shows the number of errors before and after the test using a certifier. Table 2 As is clear from the above results, the magnetic disk and storage capacity according to the example are as follows. ! ! In the case of Comparative Example 1 in which a film was provided, there was no change in the number of errors, and deterioration such as corrosion of the magnetic recording medium was prevented. On the other hand, comparative example 2 without a protective film
In the case of , the number of errors increased significantly, and it is thought that the deterioration of the magnetic properties due to corrosion of the magnetic recording medium and the lack of the medium occurred. A CSS test, which is a durability test for magnetic disks, was conducted, and in the case of the magnetic disks of Examples 1, 2, 3, and 4 and Comparative Example 1, scratches were observed on the magnetic recording medium even after 20,000 CSS cycles. Furthermore, no phenomena such as an increase in errors or a decrease in playback output were observed. In addition, in the case of Comparative Example 2, scratches occurred immediately and the CSS test could not be performed. Further, the CS of the magnetic disks according to Examples 1, 2, 3, and 4
The lubricant film thickness after 20,000 S cycles was measured by FT-IR. 88% in Examples 1 and 3 compared to before the start of the test
, Examples 2 and 4 were 94%. It is thought that applying a coupling agent as an intermediate layer was effective in retaining the lubricant against the rotation of the magnetic disk. However, for practical purposes, the disks according to Examples 1 and 3 may be used. In the above Examples and Comparative Examples, AI-
Although Mg alloy was used, other known materials such as titanium alloy, ceramics such as aluminum glass, single crystal silicon, etc. can be used. The material of the non-magnetic underlayer is Ni-P alloy, N
Examples include i-Cu-P alloy, CuCrsZn stents, and alumite, and are deposited on the substrate surface by conventional methods. The material of the magnetic recording medium is not limited to Co-Ni alloy, but includes Co-Ni-P alloy, C
o Examples include metals such as Ni-Cr alloy, Fe-Go alloy, Fe-Ni alloy, Fe-Co-Ni alloy, FesCo, and Ni, as long as they can be used as magnetic recording media. In addition to liquid lubricants, solid lubricants can be used as materials for forming the lubricant film. [Effects of the Invention] As is clear from the above description, the first invention forms an oxide film on the surface of the magnetic recording medium layer by plasma generated in an oxygen-containing Ar gas atmosphere. There is a second invention in which a magnetic recording medium layer is formed on a substrate by sputtering in an Ar gas atmosphere, and the above-mentioned Ar
Since an oxide film is formed on the surface of the magnetic recording medium layer by mixing oxygen into a gas and performing reactive sputtering, the first and second inventions have in common that an oxide film is formed on the surface of the magnetic recording medium layer using a magnetic recording medium material. The point is to form a film,
The boundary between the magnetic recording medium layer and the oxide film is strongly bonded, and a durable, extremely thin oxide film can be obtained. Therefore, these inventions provide a highly reliable magnetic disk in which the magnetic recording medium film can be reliably protected and the effective gap between the magnetic head and the magnetic recording medium film does not increase. In addition, in this second invention, no special equipment is required, and the steps from forming the magnetic recording medium layer to shaping the oxide film can be performed in a series of operations using conventional equipment, so the operation is easy. It is simple and has excellent workability.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged cross-sectional view sequentially showing a part of the process of manufacturing a magnetic disk according to an embodiment of the present invention, and FIG. 2 is a partial enlarged sectional view of a process of manufacturing a magnetic disk according to another embodiment of the invention. FIG. In the figure, (1) is an AI-M8 alloy substrate, (2) is a non-magnetic material underlayer, <<3>> is a magnetic recording medium layer, (4) is an oxide film, and (5) is a lubricant film. In addition, the same symbols in the figures indicate the same or equivalent parts. Figure 1

Claims (2)

[Claims] (1) In a magnetic disk manufacturing method in which an alloy or metal magnetic recording medium layer provided on a substrate is formed by sputtering, a film is formed on a substrate using plasma generated in an oxygen-containing Ar gas atmosphere. 1. A method of manufacturing a magnetic disk, comprising: oxidizing a surface portion of a magnetic recording medium layer to form an oxide film; and coating the oxide film with a lubricant film. (2) In a method for manufacturing a magnetic disk in which an alloy or metal magnetic recording medium layer provided on a substrate is formed by sputtering, the magnetic recording medium layer is formed on the substrate by sputtering in an Ar gas atmosphere, and the magnetic recording medium layer is formed on the substrate by sputtering in an Ar gas atmosphere. A method of manufacturing a magnetic disk, comprising: forming an oxide film on the surface of the magnetic recording medium layer by mixing oxygen with reactive sputtering, and coating the oxide film with a lubricating film.