JPH0714152A - Magnetic recording medium and magnetic disk device - Google Patents

Abstract

PURPOSE:To maintain reliability over a long period of time by treating a protective film with an inert gas and incorporating the element of the inert gas into at least the surface of the protective film. CONSTITUTION:When at least a magnetic film 4 and a protective film 5 are formed on a substrate 1 to obtain a magnetic recording medium, the protective film 5 is subjected to surface treatment in plasma of inert gas and a protective film contg. the element of the inert gas in at least the surface is formed, or a film contg. 0.1-1 atomic % Ar besides carbon as the principal constituent element is used as the protective film 5. The Ar may locally exist in the surface of the protective film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium and a magnetic storage device used for magnetic recording.

[0002]

2. Description of the Related Art In recent years, the importance of a magnetic disk device as an external storage device of a computer system has been increasing, and the recording density thereof has been remarkably improved year by year.

A magnetic recording device has a magnetic disk, a recording / reproducing magnetic head (hereinafter, simply referred to as a head), a magnetic disk rotation control mechanism, a head positioning mechanism, and a recording / reproducing signal processing circuit as main components. The general recording / reproducing method is that the head and the magnetic disk are in contact with each other before the operation is started, but by rotating the magnetic disk, a minute space is created between the head and the magnetic disk, and recording / reproducing is performed in this state. To do. At the end of the operation, the magnetic disk generally stops rotating, and the head and the magnetic disk are in contact with each other again (contact start / stop method, hereinafter referred to as CSS method). In order to improve the recording density of the magnetic recording device, the smaller the flying height of the head during recording and reproducing, the better. To ensure the flying stability of the head at that time, the surface of the magnetic disk should be as flat as possible. Is required.

Further, the frictional force generated between the head and the magnetic disk at the time of starting and stopping the apparatus causes wear of both and causes characteristic deterioration. Furthermore, if moisture or the like is present between the head and the magnetic disk while the magnetic disk is stationary, they will be firmly adsorbed, and when activated in this state, a large force is generated between the head and the magnetic disk, It may damage the magnetic disk. Such a frictional force and an attracting force tend to increase as the surface of the magnetic disk becomes flatter, which conflicts with the above-mentioned requirement for the flying stability of the head accompanying the improvement in recording density.

In order to reduce such frictional force and adsorption force, a method of forming fine irregularities on the surface of the protective film has been conventionally proposed. As an example, JP-A-55-84045 discloses a magnetic disk having a protective film with a surface roughness of 20-50 nm. JP-A-57-20925 and JP-A-3-2
Japanese Patent No. 52922 discloses a magnetic disk in which minute protrusions are formed on the surface of a protective film. Furthermore, in order to reduce the frictional force and the attraction force between the head and the magnetic recording medium, it is common to apply a lubricant to the surface of the magnetic recording medium.
A method for increasing the efficiency of lubricant adhesion to the surface of the protective film is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-67429.

[0006]

All of the above-mentioned prior arts aim at reducing the frictional force and the attractive force generated between the magnetic disk and the magnetic head, but the flying height of the head is small, and the head and the magnetic recording are small. In a high recording density magnetic disk device in which the medium is almost in contact, it is insufficient to maintain the sliding reliability for a long period of time. In particular, when a magnetic disk device is formed by using a magnetoresistive head (MR head) as a magnetic head, it is necessary to use a magnetic recording medium having a protective film having characteristics different from those of the case of using an ordinary inductive head for a long time. It is not possible to secure reliability across

An object of the present invention is to provide a magnetic disk capable of maintaining reliability for a long period of time and a magnetic disk device constructed by using the magnetic disk, particularly a magnetic disk device using a magnetoresistive head. is there.

Another object of the present invention is to provide a magnetic disk device which has high corrosion resistance and can be used in various environments.

[0009]

In order to achieve the above object, a magnetic disk having the following structure is provided. In a magnetic recording medium having at least a magnetic film and a protective film on a substrate, the protective film is surface-treated in an inert gas plasma, and at least the surface has a protective film containing the element of the inert gas. In addition, in a magnetic recording medium having at least a magnetic film and a protective film on a substrate, a film containing 0.1 to 1 at% of argon in addition to carbon as a main constituent element is used as the protective film. The argon may be localized on the surface of the protective film.

To manufacture the above magnetic recording medium, a base film (Cr film or Cr alloy film is generally used) and a magnetic film (generally a Cr film or a Cr alloy film) are formed on an ordinary non-magnetic substrate by a generally used sputtering apparatus. A Co alloy film) and a protective film are formed. When the protective film is formed by a sputtering device, it is generally a card.
A film containing carbon as the main constituent element is formed in argon or a mixed gas of argon and hydrogen / hydrocarbon using boron as a target.

As a method other than the sputtering apparatus,
For example, it is possible to form a protective film containing carbon as a main constituent element by a plasma CVD method.

After forming the above-mentioned protective film, it is possible to perform a treatment for forming irregularities on the surface of the protective film.

The protective film containing carbon as a main constituent element formed as described above is treated in an argon plasma such as reverse sputtering to form the protective film containing argon of the present invention. Can be done. Then
On the surface of the protective film, if necessary, perfluoropolyene-
A magnetic recording medium can be obtained by applying a tellurium-based lubricant.

[0014]

The magnetic recording medium having the protective film containing carbon as the main constituent element and argon as described above has a higher wear resistance of the slider than the magnetic recording medium having the protective film containing carbon as the main constituent element. The magnetic disk device constituted by using this magnetic recording medium has excellent sliding resistance. Further, since the protective film containing argon has a higher electric resistance than the protective film containing carbon as a main constituent element, which is formed by a usual sputtering method, especially when combined with a magnetoresistive head (MR head). Even when the head and the magnetic recording medium are inadvertently contacted with each other, the effect of preventing a failure due to discharge or the like is great, and the reliability of the magnetic disk device is high.

[0015]

The present invention will now be described in more detail with reference to the drawings.

FIG. 1 is a sectional view of a magnetic recording medium of the present invention, that is, a magnetic disk, and its manufacturing method will be described below.

Ni on a normal non-magnetic substrate 1 (Al alloy)
The P film 2 formed by the plating method is textured on its surface if necessary, and then the film is formed by a general sputtering method. Here, the substrate will be shown by way of example in which the NiP plating film is formed on the Al alloy, but the present invention is not limited to this, and non-magnetic metal, glass, ceramics and plastics can be used for the substrate. The same effect can be obtained when there is. In addition, the substrate surface is usually processed as a texture, but its shape is generally such that the circumferential groove or the circumferential groove and a groove having a predetermined angle cross each other. In the present invention, the same effect can be obtained. Also, apart from the above texture,
Of course, it is also possible to perform a surface treatment for enhancing the orientation of the magnetic film in the circumferential direction, for example, rubbing with a buff.

A Cr film 3 and a Co alloy film 4 are formed on the substrate surface.
After forming, the C protective film 5 is formed. The film thickness of the C protective film 5 is, for example, 20 to 60 nm.

Then, Ar pressure is set to 0.1 by the reverse sputtering method.
The surface of the C protective film is etched under conditions of 0.5 Torr and input power of 100 to 500W. The etching amount of the C protective film needs to be controlled to, for example, 5 to 30 nm. The residual film thickness of the protective film after etching is preferably as thin as possible for improving the S / N of the magnetic recording signal, but is preferably 10 nm or more for improving the sliding reliability of the device.

When the surface of the C protective film subjected to the argon etching treatment is analyzed by ESCA, Ar is detected on the surface. Table 1 shows the ESCA analysis results of the amount of Ar on the surface of the C protective film when the etching conditions were changed.

[0021]

[Table 1]

The C protective film formed by the sputtering method may contain a small amount of Ar depending on the sputtering conditions and the apparatus. In this embodiment, the surface of the C protective film as formed by sputtering is analyzed by ESCA. However, Ar was not detected. From this, it is estimated that Ar in the C protective film of this example was taken into the C protective film in the reverse sputtering process.

The etching amount of the C protective film can be controlled by the etching time when the Ar pressure and the applied power are constant.

Next, the strength of the C protective film formed above was evaluated by a continuous sliding test using a slider. The slider material was an Al ₂ O ₃ —TiC system, and the amount of wear of the C protective film was measured at a sliding speed of 2 m / s. FIG. 2 shows an example of changes in the number of passes of continuous sliding and the wear amount of the C protective film.

From these results, it was found that the amount of wear of the C protective film was significantly reduced by subjecting the surface of the C protective film formed by the sputtering method to the argon plasma treatment by the reverse sputtering method. Therefore, by using the above-mentioned magnetic disk, the sliding reliability of the magnetic disk device in which the head and the disk are in contact with each other intermittently or almost always is dramatically improved especially when the flying height of the head is 0.1 μm or less. You can

Another embodiment of the present invention will be described.

A substrate was obtained by plating a NiP film on an Al alloy, and a buff was used on the surface of the NiP substrate (a polishing liquid may be used if necessary) and the substrate was rubbed in the circumferential direction. Here, instead of the above rubbing, fine grooves (for example, surface roughness Ra1 to 5 nm measured by a stylus surface roughness meter) may be formed with a working liquid containing abrasive grains.

Using the above substrate, a Cr film is formed if necessary by a sputtering device, for example, a DC sputtering device, and then a Co-based magnetic film is formed. here,
In order to improve the recording density of the magnetic memory device, it is desirable that the coercive force of the magnetic film in the circumferential direction be larger than that in the radial direction. As a result, even if the flying height is constant, the S /
N is improved, and as a result, a disk device having a high recording density can be provided.

A protective film containing carbon as a main constituent element was formed on the magnetic film. The protective film thickness is 20 to 60 nm, preferably 30 to 50 nm.

Then, irregularities were formed on the surface of the protective film by the following steps.

A) Step of dispersing and adhering fine particles on the surface of the protective film b) Step of etching the substrate in a gas containing at least oxygen c) Step of treating the substrate in plasma d) Removal of the fine particles Step (e) Step of applying a lubricant The shape of the unevenness formed on the surface of the protective film in the above steps (a) and (b) is preferably as follows.

The heights of the hills are almost uniform, and it is preferable that the height does not exceed the protective film thickness. It is preferably 5 to 50 nm, more preferably 10 to 30 nm.

70% or more, preferably 80% or more, of the hills whose size is in the range of an equivalent diameter of 0.01 to 30 μm.

The average distance between the hills is 0.05 to
It should be 50 μm, preferably 0.1 to 20 μm.

The fine particles which can be used in the step (a) are preferably high molecular weight organic substances, for example, a material containing carbon and fluorine, specifically polytetrafluoroethylene (PTF).
E) and the like are preferable. The fine particles have an average particle diameter of 0.05.
It can be used in an amount of -20 μm, preferably 0.1-10 μm. For example, it can be dispersed in a non-aqueous solvent and sprayed to be dispersed and adhered to the substrate surface.

The processing conditions of the above step (c) may be the same as those described in the above embodiment.

The type of gas contained in the protective film differs depending on the type of gas to be surface-treated, but when argon is used, at least the surface of the treated protective film is analyzed by ESCA, It was found to contain 0.1-1 at% argon. In the present invention, the absolute amount of the second element other than carbon contained in the protective film is not essential, and it is essential that plasma treatment is performed after forming the protective film, but the content of the second element is 0.05-5.0 at%,
More preferably, it is better to contain 0.05 to 1.0 at%. Further, the amount of gas contained in the protective film also depends on the amount of etching of the surface of the protective film, and it is preferable to perform etching by 5 nm or more.

The surface treatment gas is an inert gas such as argon or nitrogen, or a fluorine-containing gas such as CF.
_You can use gas such as ₄ .

In the step (c), impurities on the surface of the protective film are removed, so that the adhesive force of the lubricant is large and the scattering of the lubricant can be prevented for a long period of time.

The above magnetic disk and magnetoresistive head (MR head, slider material is Al ₂ O ₃ --TiC system)
A device incorporating the above was constructed and the sliding resistance and the recording / reproducing characteristics were evaluated over a long period of time.

As a result, even when the number of CSS times is 10,000,
It was found that there was no damage to the disk, the increase in frictional force was small, and the sliding resistance was excellent. Also,
Also in the evaluation of the recording / reproducing characteristics, it was found that the error occurrence frequency was smaller than that of a magnetic disk having a protective film containing carbon as a main constituent element, which was formed by an ordinary sputtering method, and the device had high reliability. Further, the above-mentioned c) of the present invention).
The magnetic disk formed through the process is simply a) b)
(D) Compared with the magnetic disk formed in step (e), it has excellent corrosion resistance and the amount of contamination attached to the magnetic head slider surface is small even after continuous operation for a long time, and it is a highly reliable device. Became clear.

Here, an example of a magnetic memory device in which the above magnetic disk and a magnetoresistive head are combined is shown.
The essence of the present invention is not limited to this, and it goes without saying that the same effect can be obtained even when combined with a normal inductive head.

FIG. 3 is a schematic view of a magnetic disk device using the magnetic disk of the present invention. FIG. 3A is a schematic view of the magnetic disk device seen through the magnetic disk device from above. FIG. 3B is a schematic structural view of the magnetic disk device viewed from the AA ′ cross section of FIG.

A predetermined number of magnetic disks 7 are attached to the magnetic disk drive unit 8. A protective film mainly made of carbon is formed on the surface of the magnetic disk 7 (not shown). The magnetic head slider 9 can be moved to an arbitrary track position on the magnetic disk 7 by the magnetic head drive unit 10. Then, writing / reading of information to / from the magnetic disk 7 is performed through a thin film magnetic converter (not shown) provided in the magnetic head slider 9. The response of the write / read signal between the magnetic disk device and the host device (not shown) is performed through the recording / reproducing signal processing system 11. The recording / reproducing signal processing system 11 is specifically composed of a substrate or the like having a circuit necessary for responding to the above signals. The magnetic disk device 12 includes a magnetic disk 7 and a magnetic head 9 as essential components, and the magnetic disk 7 is rotated by a magnetic disk drive unit 8. The magnetic head drive unit 10 causes the magnetic head 9 to perform a seek operation.

As the magnetic head, of course, an inductive head can be used, but since the electric resistance of the protective film of the magnetic recording medium of the present invention is higher than that of a normal sputtered C film, it is combined with a magnetoresistive head (MR head). In this case, it is possible to provide a magnetic disk device having higher reliability and higher recording density. This is because even if the head fluctuates and the disk fluctuates unexpectedly, even if the head and the disk come into contact with each other, the resistance of the protective film of the magnetic disk is large, so that it is possible to avoid troubles due to discharge of the MR head element. .

With the above apparatus, a magnetoresistive head (MR head) was used as a head, combined with a magnetic disk having a Co-based magnetic film and the carbon protective film of the present invention, and the flying height of the head was 0.09 μm. Error during recording / playback
The rate was measured.

For comparison, a magnetic disk using a carbon film as a protective film formed by ordinary sputtering was used. As a result, when the magnetic disk of the present invention is used, the error rate is one-way higher than that when a normal magnetic disk is used.
It was found that the recording / reproducing margin of the device is large even if the size is reduced, and the magnetic disk device is highly reliable.

In the embodiment of the present invention, only the carbon film formed by sputtering as the protective film is shown, but the present invention is not limited to this. As the protective film, not only a carbon film formed by sputtering in argon, but also a carbon-based protective film formed by sputtering in a mixed gas of argon and hydrogen or hydrocarbon, formed by plasma CVD method Even if a diamond-like carbon film is used, the same effect can be obtained by performing the treatment of the present invention.

[0049]

The magnetic disk having the protective film of the present invention has a high abrasion strength of the protective film and a large electric resistance of the protective film. Therefore, the magnetic disk device equipped with the magnetic disk has a sliding reliability. A magnetic storage device which is high and has excellent recording / reproducing characteristics can be obtained especially when combined with a magnetoresistive magnetic head.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a magnetic disk according to the present invention.

FIG. 2 is a graph showing wear characteristics of the magnetic disk according to the present invention.

FIG. 3 is a structural schematic diagram of a magnetic storage device according to the present invention.

Table 1 is a table showing characteristics of the protective film according to the present invention.

[Explanation of symbols]

 1 Substrate 2 NiP Film 3 Cr Film 4 Magnetic Film 5 Protective Film 6 Lubricant 7 Magnetic Disk 8 Magnetic Disk Drive 9 Magnetic Head 10 Magnetic Head Drive 11 Recording / Reproducing Signal Processing System 12 Magnetic Disk Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Moriguchi 2880 Kozu, Odawara, Kanagawa Stock Company Hitachi Storage Systems Division (72) Inventor Fumiki Ishikawa 7-1, 1-1 Omika-cho, Hitachi-shi, Ibaraki Inside the Hitachi Research Laboratory, Hitachi Ltd. (72) Hideaki Tanaka, Inventor Hideaki Tanaka, 7-1, 1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi Ltd.

Claims (3)

[Claims] 1. In a magnetic recording medium having at least a magnetic film and a protective film on a substrate, the protective film is surface-treated in an inert gas plasma, and at least the surface of the protective film is coated with the element of the inert gas. A magnetic recording medium comprising: 2. The magnetic recording medium according to claim 1, wherein the inert gas is argon. 3. A magnetic recording medium having a protective film for protecting a magnetic layer provided on a substrate, the surface of which contains an element of the inert gas by an inert gas plasma surface treatment, and writing of information to the magnetic recording medium. A magnetic recording apparatus comprising: a magnetic head for reading / writing, and a recording / reproducing means for relatively moving the magnetic recording medium and the magnetic head to record / reproduce information.