JPH04168622A - Lubrication surface, forming method therefor and magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve quality stability and reliability of a magnetic disk device by mixing many regions each having high wettability and regions each having low wettability for lubricant on a surface, and adsorbing the lubricant in the regions each having the high wettability. CONSTITUTION:A lubrication surface 1 such as a magnetic disk surface in plane (100) is composed of regions 11 each having high wettability and regions 12 each having low wettability for lubricant 2. The lubricant 2 becomes a state such that many balls are formed on the surface 11 having high wettability on the surface 11 by means of its surface tension, and when a force is received, they alter their direction like fluctuations of seaweed. Further, when a solid surface such as a magnetic head 110 is brought into contact with the surface, the balls of the lubricant 2 hydraulically become, due to the intermediary of the regions 12 each having the low wettability, a positive pressure by means of surface tension, thereby preventing approach and contact of both surfaces such as the disk 100 and a magnetic head 110. Thus, performance, quality and reliability of a magnetic disk device are improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a lubricated surface and a method for forming the same, the present invention aims to improve the lubricity of a lubricated surface, particularly a magnetic disk surface, and improve quality stability and reliability of a magnetic disk drive. A lubricant surface is formed by having a large number of regions with good wettability and a number of regions with poor wettability with respect to the lubricant, and adsorbing the lubricant onto the regions with good wettability. Specifically, the method for forming a lubricated surface is configured, for example, by irradiating the surface with light having an intensity distribution to create the regions with good wettability and the regions with poor wettability.

[Industrial application field]

The present invention relates to lubricated surfaces, and in particular to lubricated surfaces for magnetic recording media such as magnetic disks and magnetic tapes, and methods of forming the same.

It is used as a storage medium for external storage devices in modern computers. For example, magnetic disk drives are becoming increasingly denser and faster, and as a result, there is a need to develop higher performance and more stable lubricating surfaces for magnetic disks.

C. Prior Art Lubricated surfaces are generally required to smooth the contact and sliding of two solid surfaces. One such lubricated surface that particularly requires high performance and high stability is the magnetic disk surface.

FIG. 3 is a diagram showing an example of the configuration of a magnetic disk surface. In the figure, 100 is a magnetic disk whose center is a rotational axis.For example, in order to harden the surface of A, a multilayer film is applied to a substrate 101 plated with a NiP film 102 with a thickness of 10-odd μm on one or both sides. It is made of thin films or laminated layers.

On top of that is a base layer 103 to improve adhesion. For example, a Cr layer with a thickness of 250 nm is formed, and a CoNi layer with a thickness of about 5 Q nm is formed thereon as the recording layer 104.
A magnetic film of Cr is formed, and a protective film 10 is further formed thereon.
5, for example, a carbon film having a thickness of 20 to 35 nm is formed by sputtering. 110 is a magnetic head.

Information is recorded and reproduced by electromagnetic induction by rotating the magnetic disk 100 and bringing the magnetic head 110 close to or in contact with its surface.

Therefore, for protection of both corroded surfaces and reduction of friction,
Usually, a lubricant (not shown), such as a liquid lubricant, is applied on the protective film 105. However, on surfaces that are lubricated by an extremely thin film of lubricant, known as boundary lubrication, as described above, the lubricant may separate due to friction, resulting in direct contact without any intervening lubricant, and the surface For example, magnetic disk 100
The surface will begin to wear out and cause failure.

Furthermore, in practice, it is difficult to maintain the lubricant at an appropriate thickness, and if there is too much lubricant 2, the gap between the magnetic disk 100 and the magnetic head 110 will be filled with the lubricant 2. It is good if a sufficient amount of lubricant 2 can be tolerated, but with recent high-density magnetic disks, it is not possible to widen the gap much. Maintaining the gap at a predetermined small value is extremely important in maintaining constant magneto-electrical conversion characteristics. On the other hand, as the gap becomes smaller, especially during high-speed rotation, the sliding speed is high, so the heat generation at the contact portion is also high, and as described above, the lubricant 2 is likely to separate. In addition, the magnetic disk 10
0 indicates the magnetic head 110 and magnetic disk 1 when rotation is stopped.
00 and left for a long time, the gap is filled with lubricant 2, and the magnetic head 110 is pressed against the magnetic disk 100 with a force of about 1 atmosphere due to negative pressure due to the surface tension of the lubricant 2. Therefore, a strong torque is required when starting the rotation, and friction during rotation also increases.

It is well known that the characteristics of lubricated surfaces are generally controlled by the magnitude of the bonding force of surface adsorption of lubricant and the degree of freedom of movement of lubricant molecules.

As a method for both strengthening the fixation of the lubricant and increasing the freedom of movement, it is effective to scatter minute lubricant colonies, and generally a method of providing irregularities on the surface to be lubricated, for example, the surface of the magnetic disk 100, is effective. It is being done.

FIG. 4 is a schematic diagram showing an example of the structure of a lubricated surface of a conventional magnetic disk.

In the figure, reference numeral 2 denotes a film of lubricant, for example, a liquid lubricant, and convex portions 106 and concave portions 1 formed on the surface of the base layer 102.
It covers the unevenness made of 07. In addition, base layer 1
Base layer 103 formed on 02, recording layer weight 04
．． The illustration of the protective film 105 and the like is omitted. Such irregularities are formed by polishing with a polishing cloth of about #3000, for example.

In other words, even if the surface activity is uniform, the presence of irregularities causes the lubricant layer to partially contact each other and receive load pressure at those areas, causing the lubricant in those areas to change direction, just like waving seaweed. I can do it. Furthermore, by providing unevenness, the magnetic disk 100 and the magnetic head 11
Most of the gap between the lubricant 2 and the lubricant 2 is connected to the external space by the recess 107, and the area where negative pressure is generated by the lubricant 2 is reduced, so a relatively stable lubricating surface is created with low friction during rotation and low torque when starting rotation. Furthermore, magnetic disk drives with relatively stable performance have been put into practical use.

[Invention or problem to be solved]

However, since the above-mentioned conventional lubricating surface with unevenness intentionally provides unevenness on the surface of the magnetic disk 100, the size of the gap between the recording layer 104 and the magnetic head 110 varies depending on the location. As a result, there is a serious problem in electromagnetic conversion characteristics, particularly in the occurrence of write/read errors due to the generation of noise, and a solution to this problem is required.

[Means to solve the problem]

The above problem is solved by creating a lubricant 2 in which a large number of areas 11 with good wettability and areas 12 with poor wettability are mixed on the surface of the lubricant 2, and the lubricant 2 is adsorbed in the areas 11 with good wettability. Can be solved by surface. Specifically, the problem can be solved by a lubricating surface having an active surface that reacts with the bonding group of the lubricant 2 in the region 11 with good wettability, and having molecules of the lubricant 2 fixed to the active surface portion. . Furthermore, if the surface of the recording surface that contacts the recording head is made of the aforementioned lubricating surface, a high-performance magnetic recording medium can be formed.

The formation of such a lubricated surface is achieved by irradiating the surface with light having an intensity distribution or by partially irradiating plasma to separate the areas 11 with good wettability and the areas 12 with poor wettability. This can be solved by a method that causes this problem to occur. Furthermore, specifically, a compound having multiple photosensitive groups within the molecule is applied to the surface and then light with an intensity distribution is irradiated.

By supersaturating the surface activator on a surface exposed to a gas containing the surface activator and condensing it in the form of minute droplets, or by irradiating an electron beam on a surface exposed to a trace amount of contaminant gas in a low vacuum. , the region 11 with good wettability and the region 1 with poor wettability
2 and a method for forming a lubricating surface that causes the lubricant 2.
Alternatively, a method for forming a lubricated surface in which the lubricant 2 is attached to a surface exposed to a gas containing the lubricant 2 by supersaturation, and the lubricant 2 is fixed in a portion where the light intensity is high by irradiating the lubricant 2 with light having an intensity distribution. This can be effectively solved by

[Effect]

FIG. 1 is a diagram showing the principle of the present invention. In the figure, 1 is a lubricated surface, for example, the magnetic disk 100 surface, 11 is a region with good wettability to the lubricant 2, and 12 is a region with poor wettability.

As can be easily seen from the figure, the surface tension of the lubricant 2 causes the lubricant 2 to form a state in which many balls are formed on the surface 11 with good wettability on the lubricant surface 1, and when a force is applied, the lubricant 2 is shaped like a waving seaweed. It changes. Moreover,
When a solid surface, for example the magnetic head 110, comes into contact with this, the balls of lubricant 2 will move between the areas 1 with poor wettability.
2, the liquid pressure becomes positive due to surface tension, and it is possible to prevent the two surfaces, for example, the magnetic disk 100 and the magnetic head 110, from coming into close contact with each other.

That is, during rotation, the friction is small, and since the negative pressure caused by two layers of lubricant does not act as in the conventional case, the torque at the time of starting rotation can also be reduced.

In addition, in FIG. 1 above, the lubricant 2 shows the case where the same type of lubricant is used, or the lubricant 2 has a plurality of different wettability values in the region 11 with good wettability, and the lubricant 2 corresponds to the wettability value. a plurality of different lubricants 2 are respectively adsorbed to the regions 11 with good wettability to increase the independence of the balls of the lubricant 2,
A more stable lubricated surface may be obtained.

〔Example〕

The above-mentioned magnetic disk 100 is used as a sample, and the main points of each embodiment and a specific method of forming the same will be explained below in the order of steps.

First Example Step (1): A positive resist is spin-coated to a thickness of about 1 μm on the protective film 105 of the magnetic disk 100, and baked at 130° C. for 115 minutes in a nitrogen stream.

Step (2): An exposure mask, such as a chrome mask, uniformly formed with a striped pattern of, for example, a size of about 0.5 to 1.0 μm is placed on the above-mentioned treated substrate, and after exposure, an appropriate A resist pattern is formed by processing with a suitable developer.

Step (3): The protective film 105 exposed on the resist pattern is exposed to the resist pattern by irradiating the entire surface of the treated substrate with plasma, for example, oxygen plasma. For example, a portion of the carbon film is activated. Note that if the plasma treatment is continued until the resist portion of the resist pattern is decomposed and removed by the plasma, activation and removal of the resist pattern can be accomplished in one step. The area irradiated with plasma causes detachment of adsorbed molecules and activation of the activated partial surface due to the energy of the charged particles, for example, C=
A region 11 with good wettability is formed which has zero aligned partial surfaces, ie, active surfaces.

Step (4): A lubricant having a polar group, for example, -0H group in the molecule, is applied to the treated substrate 2. For example, 8O-CH2
-CF2 (-0-C2F,), -(0-CFri,
The lubricant surface of the present invention can be obtained by spin-coding -0CF2-CH20H and then heating it at 70°C for 15 minutes to fix the molecules of lubricant 2 on the active surface portion, that is, the region 11 with good wettability. It will be done.

In the above embodiments, a resist pattern was formed using an exposure mask having a uniform striped pattern, and plasma irradiation was performed, or by directly irradiating the surface with light with an intensity distribution, for example, laser light. The adsorbed molecules may be detached and activated by partial heat generation or direct action of photon energy, and an appropriate lubricant 2 may be fixed to that portion. In this case, the process of forming the lubricating surface is greatly reduced, which is economical. As a method of irradiating the surface with light having an intensity distribution, a speckle pattern of laser light can be used.

Figure 2 is a diagram showing an example of forming a striped pattern.
(a) is a conceptual diagram of the device, and (b) is an enlarged view of an example of a speckle pattern. That is, the laser light source 200. For example, Ar ultraviolet light with a wavelength of 351 nm is incident on the lens system 202 via the mirror 201 and converted into an expanded beam by the diffuser plate 203. For example, when the target surface 204 is irradiated through a quartz glass plate with one side roughened,
During this time, the laser beams cause interference and form a speckle pattern with a minimum diameter of several μm as shown in an enlarged view in FIG. Such a speckle pattern may be used to directly form a surface 11 with good wettability on the target surface.

It goes without saying that it may also be used for exposure to form the resist pattern of the above embodiment.

Second Example Step (1): A compound having a plurality of photosensitive groups, for example, two photosensitive groups in its molecule, such as a bisazide compound, is uniformly applied onto the protective film 105 of the magnetic disk lOO.

Step (2): A speckle pattern is formed on the treated substrate using light with an intensity distribution, for example, the ultraviolet laser light. As a result, only the bright portion of the interference light is activated in the photosensitive groups, and one photosensitive group reacts with the substrate, and the other photosensitive group comes to the surface to form a region 11 with good wettability.

Step (3): Apply lubricant 2 to the treated substrate. For example, the lubricating surface of the present invention can be obtained by applying a fluorinated carbon lubricant in a nitrogen stream and then treating it with an alcohol-based solvent to dissolve and remove the bisazide compound in the non-exposed areas, that is, the dark areas. It is formed.

Third embodiment process (1): magnetic disk 100 provided with protective film 105
is cooled to a low temperature, for example -10°C.

Step (2): Treat the cooling substrate with a surface activator, for example,
Approximately 10% of methyl isobutyl ketone is gasified and exposed to a mixed gas, for example, mixed nitrogen, to cause methyl isobutyl ketone to condense on the surface in the form of minute droplets.

Step (3) The above treated substrate is heated in air at 80°C for 930 minutes to oxidize and evaporate the dew condensed droplets.
The minute portion where the droplet was located contains an active group, for example, C
A region 11 with good wettability in which =0 groups are arranged is formed.

Step (4): A lubricant having a polar group, for example, -0H group in the molecule, is applied to the treated substrate 2. For example, HO-CH2
-CF2 (-0C2F4)--(0-CF2), -0
After spin-coding CF2-CH20H, the lubricant 2 molecules are fixed in the active surface portion, ie, the region 11 with good wettability, by heating for 915 minutes at 70° C. to obtain the lubricant surface of the present invention.

In the above embodiment, the surface activating agent is supersaturated to condense in the form of minute droplets to first form a region 11 with good wettability, and then the molecules of the lubricant 2 are fixed to that region. Alternatively, the lubricant 2 is deposited in the form of droplets by supersaturation on the surface exposed to the lubricant 2 or a gas containing the lubricant 2,
For example, the lubricant surface of the present invention may be formed by directly fixing the molecules of the lubricant 2 in the droplet portion by heat treatment or the like. Alternatively, the lubricant surface of the present invention can be formed in the same way by uniformly depositing a layer of lubricant 2 on the surface by supersaturation and irradiating it with light with an intensity distribution, thereby fixing the lubricant 2 in areas where the light intensity is high. can.

Fourth Embodiment The above-described embodiments are all based on forming a region 11 with good wettability first, or depending on the characteristics of the lubricant 2, a region 12 with poor wettability may be formed. It goes without saying that the lubricated surface of the present invention can be obtained in the same way even if the lubricant 2 is not fixed only to that portion. As a specific method for forming such a region 12 with poor wettability.

For example, a protective film 1 is placed in a low vacuum of about 1O-5 Torr.
The magnetic disk 100 provided with 05 is exposed and irradiated with an electron beam to form an organic molecular film generated from residual trace gas, for example, Hyde mouth-to-mouth.

By applying a so-called contamination method, areas 11 with good wettability and areas 12 with poor wettability are mixed in a striped pattern, and an appropriate lubricant 2 is applied to the areas 11 with good wettability.
Similarly, the lubricating surface of the present invention can be obtained by adhering to the lubricating surface of the present invention.

The embodiments described above are merely examples, and it goes without saying that preferred materials and configurations, or combinations thereof, may be used as long as they comply with the spirit of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, the lubricant 2 forms a state in which a large number of balls are formed on the surface 11 with good wettability on the lubricating surface 1 due to its surface tension, and when subjected to force, it becomes like a seaweed. So change the direction.

Moreover, there is a solid surface on top of this, for example, the magnetic head 11.
When the poles of the lubricant 2 come in contact with each other, a region 12 with poor wettability exists between them, so the liquid pressure becomes positive pressure due to surface tension, and is applied to both surfaces, for example, the magnetic disk 10.
0 and the magnetic helad 110 can be prevented from coming into close contact with each other. In other words, when the product rotates, the friction is small, and since the negative pressure caused by the two layers of lubricant does not act as in conventional products, the torque at the start of rotation can also be reduced.

For example, it will greatly contribute to improving the performance, quality, and reliability of magnetic disk drives.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a diagram showing an example of forming a striped pattern, Fig. 3 is a diagram showing an example of the configuration of a magnetic disk surface, and Fig. 4 is a diagram showing a conventional magnetic disk. FIG. 3 is a schematic diagram showing an example of the structure of a lubricated surface of the lubrication surface. In the figure, 1 is a lubricated surface, 2 is a lubricant, 11 is a region with good wettability, 12 is a region with poor wettability, 100 is a magnetic disk, and 110 is a magnetic head.

Claims (9)

[Claims] (1) Numerous areas with good wettability for the lubricant (2) (
11) and a region (12) with poor wettability are mixed on the surface, and the region (11) with good wettability is coated with a lubricant (2).
) is adsorbed on the lubricated surface. (2) The region (11) with good wettability has an active surface that reacts with the bonding group of the lubricant (2), and molecules of the lubricant (2) are fixed to the active surface portion. The lubricated surface according to claim (1). (3) The surface of the recording surface in contact with the recording head is claimed in claim (1).
A magnetic recording medium having a lubricated surface as described above. (4) By irradiating the surface with light with an intensity distribution, the areas with good wettability (11) and the areas with poor wettability (12) are
) The method for forming a lubricated surface according to claim 1, characterized in that: (5) By partially irradiating the surface with plasma, the areas with good wettability (11) and the areas with poor wettability (12) are
) The method for forming a lubricated surface according to claim 1, characterized in that: (6) After applying a compound having multiple photosensitive groups in the molecule to the surface and irradiating it with light with an intensity distribution, the above-mentioned areas with good wettability (11) and areas with poor wettability (12) are formed.
2. The method of forming a lubricated surface according to claim 1, wherein: (7) The region (11) with good wettability is obtained by performing a process that at least includes condensing the surface activator in the form of minute droplets by supersaturating the surface activator on the surface exposed to the gas containing the surface activator. 2. A method for forming a lubricated surface according to claim 1, characterized in that a region (12) with poor wettability is formed. (8) The lubricant (2) is attached to the surface exposed to the lubricant (2) or a gas containing the lubricant (2) by supersaturation, and the light with an intensity distribution is irradiated to the area where the light intensity is high. A method for forming a lubricated surface, characterized by fixing the lubricant (2). (9) The area with good wettability (11) is obtained by irradiating the surface exposed to trace amounts of contaminant gas in a low vacuum with an electron beam.
2. A method for forming a lubricated surface according to claim 1, characterized in that a region (12) with poor wettability is formed.