JPH05298682A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the attraction of a lubricating film and a floating magnetic head by forming the carbon film to be laminated on a magnetic thin film by a sputtering method in a gaseous hydrocarbon atmosphere contg. gaseous argon and oxygen. CONSTITUTION:The formation of the carbon film to be laminated on the magnetic thin film 2 on a substrate 1 is executed by the sputtering method in the mixing gas with the gaseous hydrocarbon atmosphere contg. the gaseous argon and the oxygen to form a protective film 3 contg. the oxygen. The lubricating film 4 by a liquid lubricant is then formed on the protective film 3. The attraction state of the lubricating film and the floating magnetic head is thus weakened by the presence of the oxygen in the protective film constituted by the thin film of the carbon contg. the oxygen, by which the hindrance of a starting operation is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium.

[0002]

2. Description of the Related Art In a magnetic recording medium (magnetic disk) recording / reproducing apparatus, in order to enable stable recording / reproducing of a signal without damaging the surface of the magnetic recording medium, a recording operation is performed at a time of recording an information signal on a magnetic disk. A flying-type magnetic head is used in which the magnetic gap of the magnetic head is floated above the surface of the magnetic recording medium at a predetermined minute interval during the reproduction operation of the information signal from the magnetic disk. For example, various types are used to facilitate the contact start / stop operation and load / unload operation, and to prevent the flying height of the magnetic head from changing significantly due to surface wobbling that occurs when the magnetic disk rotates. It is well known that there have been proposals that have been devised. By the way, a magnetic disk recording / reproducing apparatus is a contact start / stop system (CS
In the case where the recording / reproducing operation is performed by adopting the S system), the floating magnetic head floats above the surface of the magnetic disk after the magnetic disk in the stopped state starts to rotate during start-up and operation. If the floating magnetic head is in contact with the surface of the rotating magnetic disk during the period up to, and the number of rotations of the magnetic disk that is rotating at a high speed at the specified rotation speed during the stop operation decreases. In addition, since the floating magnetic head comes into contact with the rotating magnetic disk surface, when the floating magnetic head and the magnetic disk surface are in contact with each other in both of the above-mentioned states, the floating magnetic head and the magnetic disk surface are contacted with each other. Abrasion occurs, and in the worst case, the recorded contents of the magnetic disk may be destroyed.

[0003]

A flying magnetic head and a rotating magnetic disk surface are in contact with each other during both start-up operation and stop operation in a magnetic recording medium (magnetic disk) recording / reproducing apparatus. In order to solve the above-mentioned problems caused by the above, a magnetic disk has conventionally been provided with a protective film and a lubricating film on its magnetic thin film. And, as the above-mentioned protective film, a hard film such as a carbon film or a silicon dioxide film is generally used, and as a lubricating film, in order to increase the adhesion with the above-mentioned protective film, the molecular end Perfluoropolyether (PFPE) having a polar group is used for the formation of the protective film by the carbon film in an argon gas atmosphere.
The most general method is to deposit a carbon film on a magnetic thin film by using a sputtering method, but as a method for forming a protective film using a carbon film, Japanese Patent Laid-Open No. 61-11177 is proposed.
No. 27 discloses that a carbon film is deposited and formed on a magnetic thin film by a sputtering method in a mixed gas atmosphere of argon gas and hydrogen gas, or in a mixed gas atmosphere of argon gas and hydrocarbon gas. A method of depositing a carbon film on a magnetic thin film by a sputtering method is also disclosed. When a magnetic disk having a structure in which a protective film and a lubricating film are provided on a magnetic thin film as described above is used, a contact start / stop system (CS
Even when the flying magnetic head and the rotating magnetic disk surface are in contact with each other at both the start-up operation and the stop operation of the magnetic disk recording / reproducing apparatus adopting the S system), It is possible to eliminate such a big problem.

By the way, in recent years, with the demand for higher density recording on recording media, higher density recording has also been performed on magnetic disks. In order to perform the recording / reproducing operation of the density-recorded magnetic disk with high reliability, the flying height of the magnetic gap of the floating magnetic head with respect to the surface of the magnetic recording medium should be extremely small. Therefore, a magnetic disk having an ultra-smooth surface is required. However, when the magnetic disk has an ultra-smooth surface as described above, when the lubricating film on the protective film provided on the magnetic thin film of the magnetic disk and the floating magnetic head come into contact with each other, the lubricating film and the flying magnetic There was a problem that the head and the head would be in a strong adsorption state and the operation would be poor after each start, and a solution to that problem was sought.

[0005]

According to the present invention, a step of depositing a magnetic thin film on a substrate, and a sputtering method in a mixed gas atmosphere of a hydrocarbon gas containing argon gas and oxygen are formed on the magnetic thin film. Provided is a method of manufacturing a magnetic recording medium, which comprises the steps of depositing and forming a protective film of a carbon thin film containing oxygen and forming a lubricating film of a liquid lubricant on the protective film of a carbon thin film containing oxygen. To do.

[0006]

The carbon film to be laminated on the magnetic thin film deposited and formed on the substrate is formed by the sputtering method in the mixed gas atmosphere of the argon gas and the hydrocarbon gas containing oxygen. The presence of oxygen in the protective film made of a thin carbon film weakens the adsorption state between the lubricating film and the flying magnetic head, and prevents the start-up operation from being disturbed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete contents of the method for producing a magnetic recording medium of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1
Is a block diagram showing a schematic configuration of an apparatus used in some steps when carrying out the method for manufacturing a magnetic recording medium of the present invention,
FIG. 2 is a sectional view of a part of the magnetic recording medium, and FIG. 3 is a diagram showing the relationship between the amount of lubricant and the coefficient of static friction. FIG. 2 is a sectional view of a part of a magnetic recording medium (magnetic disk) produced by the method for producing a magnetic recording medium of the present invention, in which 1 is a substrate having a mirror-like surface (for example, a crystal having an average surface roughness of 5 nm). 2) a magnetic thin film (for example, a magnetic thin film made of a magnetic alloy), 3 a protective film made of a carbon thin film containing oxygen, 4 a substance having a polar group at the molecular end, for example, perfluoropolyene It is a lubricating film made of ether (PFPE). In practice, a base layer made of, for example, a chromium thin film may be provided between the substrate 1 and the magnetic film 2.

As a result of various experiments conducted by the inventor of the present invention, the method of manufacturing a magnetic recording medium of the present invention has a magnetic thin film 2 formed on the substrate 1 for protection of the magnetic thin film 2 adhered and formed on the substrate 1. When the protective film 3 to be laminated is made of a carbon thin film containing oxygen, a substance having a polar group at the molecular end is selected depending on the amount of oxygen contained in the carbon film forming the protective film 3. This is based on the finding that the adsorption state between the lubricating film 4 and the floating magnetic head formed by using the protective film 3 is changed by the fact that the protective film 3 is formed of a carbon thin film containing oxygen as described above. The phenomenon in which the adsorption state between the lubricating film 4 formed by using a substance having a polar group at the molecular end and the floating magnetic head changes when the above is used is included in the carbon film forming the protective film 3. The presence of oxygen, In the substance having a polar group at the molecular end used for the construction of the lubricating film 4 on the protective film 3, the adsorption action of the polar group to the carbon film becomes large, and accordingly, the floating type in contact with the lubricating film 4 It is considered that this is because the attraction force of the lubricating film 4 to the magnetic head is reduced.

By the way, when the protective film 3 is made of a carbon thin film containing oxygen as described above and oxygen gas is directly introduced during the formation of the protective film 3,
Since most of the carbon film is oxidized to form a gas such as carbon monoxide or carbon dioxide, it is practically impossible to form the protective film 3 having a predetermined thickness. Therefore, in the method of manufacturing the magnetic recording medium of the present invention, the step of depositing the magnetic thin film 2 on the substrate 1 and the sputtering method in the mixed gas atmosphere of the argon gas and the hydrocarbon gas containing oxygen are performed. The process of depositing and forming the protective film 3 of a carbon thin film containing oxygen on the magnetic thin film 2 and the process of forming the lubricating film 4 of a liquid lubricant on the protective film 3 of a thin film of carbon containing oxygen are described above. By producing a recording medium, a protective film 3 made of a carbon thin film containing oxygen can be efficiently attached and formed on the magnetic thin film 2 to easily produce a magnetic recording medium which can satisfactorily solve the conventional problems. I made it possible.

FIG. 1 shows an example of an apparatus used in the step of depositing a protective film 3 of a carbon thin film containing oxygen on a magnetic thin film 2 of an intermediate product in which a magnetic thin film 2 is deposited on a substrate 1. 1 is a block diagram showing a source of argon gas used as one of the atmospheric gases at the time of film formation, 6, 8 and 11 are pipes for passing the atmospheric gas, 7 is a valve, and 9 is A liquid hydrocarbon container containing oxygen, 10 is a liquid hydrocarbon containing oxygen, and 12 is a sputtering apparatus equipped with a carbon target. The argon gas supplied from the argon gas supply source 5 is adjusted to a predetermined pressure and supplied to the pipe 6, and after the flow rate is adjusted by the valve 7, the oxygen in the liquid container 9 of the hydrocarbon containing oxygen is removed. Pipe 1 passing through the hydrocarbon liquid containing oxygen as bubbles in the liquid containing hydrocarbon
1 is supplied as an atmospheric gas to a sputtering apparatus 12 equipped with a carbon target (for example, a graphite target).

Since the oxygen-containing hydrocarbon liquid in the oxygen-containing hydrocarbon liquid container 9 is maintained at a predetermined temperature by a temperature control device (not shown),
The atmosphere gas supplied from the liquid container 9 of the hydrocarbon containing oxygen through the pipe 11 to the sputtering apparatus 12 having the carbon target is a mixture of argon gas and hydrocarbon gas containing oxygen in a desired mixing ratio. It is gas. In the sputtering apparatus 12, as described above, the magnetic thin film 2 is formed on the substrate 1 by the sputtering method using the carbon target in the atmosphere gas supplied from the liquid container 9 of the hydrocarbon containing oxygen through the pipe 11.
On the magnetic thin film 2 of the intermediate product in the state where the carbon dioxide is adhered and formed, a protective film 3 of a predetermined thickness made of a carbon thin film containing oxygen.
To adhere and form.

The following are some examples of specific manufacturing examples (embodiments) of the magnetic recording medium according to the above-described manufacturing method of the magnetic recording medium of the present invention. [Example 1] A crystallized glass plate having an average surface roughness of 5 nm was used as a substrate 1. First, a chromium layer having a thickness of 45 nm was formed as a base layer on the surface of the substrate by a sputtering method. To do. Next, a magnetic alloy film made of cobalt, chromium, tantalum, and platinum is formed as a magnetic thin film on the above-mentioned underlayer by a sputtering method so as to have a thickness of 55 nm. Argon gas is used as an atmospheric gas used during film formation by the above-described sputtering method. Then, an atmosphere gas obtained by passing argon gas through methanol (CH3OH) at 65 degrees Celsius used as a liquid of hydrocarbon containing oxygen, that is, a mixed gas of argon gas and methanol gas is used as an atmosphere gas (gas pressure). Is 20 mTorr), and a protective film 3 of a predetermined thickness made of a carbon thin film containing oxygen is deposited on the magnetic thin film 2 using a graphite target. A lubricant film 4 made of a liquid lubricant made of a substance having a polar group at its molecular end, for example, perfluoropolyether (PFPE) is adhered and formed on the protective film 3 by a dipping method.

[Embodiment 2] Argon gas and methanol gas used as atmosphere gases when a protective film 3 of a predetermined thickness of a carbon thin film containing oxygen is adhered and formed on a magnetic thin film 2 using a graphite target. A magnetic recording medium was manufactured under the same conditions as in [Example 1] except that the gas pressure of the mixed gas was 40 mTorr. [Comparative Example] Magnetic thin film 2 using a graphite target
Argon gas as an atmosphere gas (gas pressure of 20 m
Torr), except for the conditions described above [Example 1]
A magnetic recording medium of a comparative example was manufactured in the same manner as in.

FIG. 3 is a lubricant for a magnetic recording medium prepared by [Example 1], [Example 2] and [Comparative Example] of a specific magnetic recording medium according to the method for producing a magnetic recording medium of the present invention. It is a characteristic view which shows the relationship between an adhesion amount and a static friction coefficient. A curve indicated by triangles in FIG. 3 is a characteristic of the magnetic recording medium manufactured according to [Comparative Example], and a curve indicated by white circles in FIG. 3 is a magnetic recording medium manufactured according to [Example 1]. The curve indicated by a black circle in FIG. 3 is the characteristic of the magnetic recording medium manufactured according to [Example 2]. Comparing each characteristic diagram showing the relationship between the lubricant adhesion amount and the static friction coefficient in the magnetic recording medium shown in FIG.
The magnetic recording medium manufactured by the method for manufacturing a magnetic recording medium of the present invention is provided on a magnetic thin film in a magnetic disk as compared with a conventional magnetic recording medium, that is, a magnetic recording medium using a carbon thin film as a protective film. It can be seen that the adsorption state between the lubricating film 4 and the floating magnetic head is weak when the lubricating film on the protective film and the floating magnetic head are in contact with each other.

[0015]

As is clear from the above description, in the method of manufacturing a magnetic recording medium of the present invention, the carbon film to be laminated on the magnetic thin film adhered and formed on the substrate is formed by argon gas. In a mixed gas atmosphere of oxygen and a hydrocarbon gas containing oxygen, the adsorption state between the lubricating film and the levitation magnetic head due to the presence of oxygen in the protective film formed by the carbon thin film containing oxygen by performing the sputtering method. It is possible to easily manufacture a magnetic recording medium capable of preventing the start-up operation from being hindered.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an apparatus used in some steps when carrying out a method of manufacturing a magnetic recording medium of the present invention.

FIG. 2 is a sectional view of a part of a magnetic recording medium.

FIG. 3 is a diagram showing the relationship between the amount of lubricant and the coefficient of static friction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate having a mirror surface, 2 ... Magnetic thin film, 3 ... Protective film composed of a thin film of carbon containing oxygen, 4 ... Lubrication by a substance having a polar group at the molecular end, for example, perfluoropolyether (PFDE) Membrane, 5 ... Argon gas supply source used as one of atmospheric gases during film formation, 6, 8,
11 ... Pipe for passing atmospheric gas, 7 ... Valve, 9
... a liquid container for a hydrocarbon containing oxygen, 10 ... a liquid for a hydrocarbon containing oxygen, 12 ... a sputtering apparatus equipped with a carbon target,

Claims (1)

[Claims] 1. A step of depositing a magnetic thin film on a substrate, and a carbon thin film containing oxygen on the magnetic thin film by a sputtering method in a mixed gas atmosphere of argon gas and hydrocarbon gas containing oxygen. A method of manufacturing a magnetic recording medium, comprising a step of depositing and forming a protective film, and a step of forming a lubricating film of a liquid lubricant on the protective film of a carbon thin film containing oxygen.