JPH06139563A - Production of magnetic disk - Google Patents

Abstract

PURPOSE:To obtain a uniform lubricating layer by applying a first soln. prepared by diluting a fluorine-base lubricant with a volatile org. solvent on a magnetic layer to form a lubricant layer, and then applying a second soln. having lower concn. of the fluorine-base lubricant than the first soln. on the lubricant layer. CONSTITUTION:The first soln. prepared by diluting a fluorine-base lubricant with a volatile org. solvent is applied on a protective layer 5 by spin coating to form a lubricant layer 7. The layer 7 includes such a part 8 where the lubricant layer is enough formed and such a part 9 where the lubricant layer is not enough formed. Then the second soln. having the concn. of fluorine-base lubricant 10-20% of the concn. of the first soln. is applied on the layer 7 by spin coating. Thereby, the part 8 is removed while the part 9 is covered with a new lubricant 10 to form a uniform lubricant layer 7.

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 disk used in a magnetic recording / reproducing apparatus or the like.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing a magnetic disk. In FIG. 4, 1 is a base made of a material such as Al,
Reference numeral 2 denotes a Ni-P film provided on the base 1,
The i-P film 2 constitutes a substrate. A base film 3 is provided on the substrate, and the base film 3 is made of a material such as Cr. A magnetic layer 4 is provided on the underlayer film 3, and the magnetic layer 4 is made of a magnetic material such as Co—Cr—Ta. A protective layer 5 is provided on the magnetic layer 4, and the protective layer 5 is made of C or the like. Reference numeral 6 is a lubricating layer provided on the protective layer 5.
The lubricating layer 6 is formed on the protective layer 5, as shown in FIG. The unevenness as shown in FIG. 5 is formed on the protective layer 5 because the substrate is textured and the films are formed by a thin film technique such as a sputtering method or a plating method. This is because the irregularities on the top are reflected as the irregularities on the surface of the protective layer 5.

The lubricating layer 6 is formed by coating the protective layer 5 with a fluorine-based lubricant diluted with a volatile organic solvent. The following two methods are known as a method for applying a fluorine-based lubricant. One holds a magnetic disk having a protective layer 5 formed by a disk hanger, and the magnetic disk is dipped together with the disk hanger in a solution prepared by diluting a fluorinated lubricant with a volatile organic solvent, and then the magnetic disk is pulled up from the solution. Alternatively, it is a method of forming the lubricating layer 6 by evaporating the volatile organic solvent by extracting the solution. On the other hand, while rotating the magnetic disk at a low speed with a spindle motor, a solution prepared by diluting a fluorine-based lubricant with a volatile organic solvent is injected onto the magnetic disk, and then the magnetic disk is rotated at a high speed to evaporate the solvent. This is a method called spin coating in which the lubricating layer 6 is formed by going on.

Since the surface roughness Ra of the conventional magnetic disk is 60 to 120Å, the difference in roughness is 10%.
As a result, the difference in the thickness of the lubricating layer is inevitably allowed to be 6 to 12 Å. Therefore, if the error in the thickness of the lubricating layer is controlled to about 10Å, sufficient lubricity when sliding with the magnetic head can be obtained.

However, in recent years, the flying distance between the magnetic disk and the magnetic head has been narrowed to increase the storage capacity of the magnetic recording / reproducing apparatus. Therefore, the surface roughness of the magnetic disk is about 10 to 80Å. As the surface roughness of the magnetic disk becomes smaller in this way, the error in the thickness of the lubricating layer must be controlled to about 5Å.

[0006]

However, in the conventional method of forming the lubricating layer, it is difficult to control the thickness to about 5Å, and there is a problem that the slidability between the magnetic head and the magnetic disk deteriorates. .

The present invention solves the above-mentioned conventional problems, and provides a method for manufacturing a magnetic disk, which can form a lubricating layer within a predetermined error even if the surface roughness of the magnetic disk becomes small. It is intended to be provided.

[0008]

To achieve this object, a first solution prepared by diluting a fluorine-based lubricant with a volatile organic solvent is applied on the magnetic layer to form a lubricating layer, and then a fluorine layer is formed. The second lubricant, which is diluted with a volatile organic solvent and has a lower concentration of fluorine lubricant than the first solution
Is applied on the lubricating layer.

[0009]

By this method, the portion where the lubricating layer is excessively adhered by the first solution is dissolved by the second solution, and the portion where the lubricating layer is not sufficiently adhered by the first solution is treated by the second solution. The lubricating layer can be sufficiently attached.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a magnetic disk according to an embodiment of the present invention will be described below with reference to FIGS. 1 (a) (b) (c).

First, FIG. 1A shows a magnetic disk before forming a lubricating layer, and 5 is a protective layer, which is the same as the conventional structure. Although not shown, the substrate, the base film, and the magnetic layer have the same structure as the conventional one. Next, the first solution, that is, a fluorine-based lubricant (for example, Fo manufactured by Monte Floro Co., Ltd.)
mblin Z) is diluted with a volatile organic solvent to prepare a solution (concentration of the fluorine-based lubricant is 0.01% to 1.00%), and the first solution is applied onto the magnetic disk by spin coating. Then, the lubricating layer 7 shown in FIG. 1B is formed. At this time, as shown in FIG. 1B, the lubricating layer 7 is formed with a portion 8 where the lubricating layer 7 is excessively formed and a portion 9 where the lubricating layer 7 is insufficiently formed. Next, the second solution, that is, a fluorine-based lubricant (for example, Fombl manufactured by Monte Floro Co., Ltd.
in Z) is diluted with a volatile organic solvent, and the concentration of the fluorinated lubricant is set to 1 of the concentration of the fluorinated lubricant of the first solution.
A solution of 0% to 20% is prepared. This second solution is applied onto the magnetic disk by spin coating.
Then, the portion 8 shown in FIG. 1 (b) is removed, and a new lubricant is attached to the portion 9 to form a uniform lubricating layer 7 as shown in FIG. 1 (c). It is considered that such a phenomenon occurs due to the following reasons. Regarding the portion 8, since the intermolecular force between the molecules forming the protective layer 5 and the molecules forming the lubricating layer 7 is weak, when the second solution is applied, the portion 8 is removed. Since the intermolecular force between the molecules forming the protective layer 5 and the molecules forming the lubricating layer 7 is strong, is not removed even when the second solution is applied. Further, since the portion 9 is close to the protective layer 5 (because of the large intermolecular force), when the second solution is applied, the replenishment portion 10 is attached to the portion 9.

It is considered that the lubricating layer 7 can be uniformly formed on the protective layer 5 by such a phenomenon.

Further, it will be specifically described that this embodiment can form the lubricating layer 7 more uniformly than the conventional example.

First, a lubricating layer having a thickness of about 80Å was formed on the protective layer by using the methods of the present example and the conventional example, and the thickness distribution of the lubricating layer in the radial direction was measured. The results are shown in FIGS. 2 (a) and 2 (b). As can be seen from FIG. 2A, in this embodiment, the variation in film thickness is about 5Å. Therefore, even if the surface roughness of the magnetic disk becomes small, the lubricating layer can be formed uniformly, and the lubricity when sliding on the magnetic head is improved. Further, as can be seen from FIG. 2B, in the conventional example, unlike the present example, the process is performed once without forming the lubricating layer, so that the film thickness greatly varies. With this, when a lubricating layer is formed on a magnetic disk having a small surface roughness, the lubricity when sliding on the magnetic head deteriorates.

Next, the reason why the concentration of the fluorinated lubricant in the second solution is set to 10% to 20% of the concentration of the fluorinated lubricant in the first solution will be described.

FIG. 3 is a graph showing the relationship of variation in film thickness with respect to the second solution. As can be seen from FIG. 3, when the concentration of the fluorine-based lubricant in the second solution is set to 10% to 20% of the concentration of the first fluorine-based lubricant, the variation in the film thickness is 3% to 5%. You can see that it is getting smaller.

As described above, in this embodiment, a uniform lubricating layer can be formed by forming the lubricating layer with the first solution and then forming the lubricating layer with the second solution.

[0018]

According to the present invention, the first layer obtained by diluting the fluorine-based lubricant with the volatile organic solvent is applied on the magnetic layer to form the lubricating layer, and then the fluorine-based lubricant is added with the volatile organic solvent. The second solution, which is diluted with the solution and has a lower concentration of the fluorine-based lubricant than the first solution, is applied onto the lubricating layer, so that the portion where the lubricating layer is excessively adhered to the first solution is It is possible to form a uniform lubrication layer because the second solution can sufficiently adhere the lubrication layer to the portion where the adhesion of the lubrication layer is insufficient with the first solution. It is possible to improve the lubricity when sliding with the magnetic head.

[Brief description of drawings]

FIG. 1 is a sectional view showing a method of manufacturing a magnetic disk according to an embodiment of the present invention.

FIG. 2 is a graph showing variations in the thickness of the lubricating layer.

FIG. 3 is a graph showing the relationship between the concentration of the fluorinated lubricant in the second solution and the variation in the thickness of the lubricating layer.

FIG. 4 is a sectional view showing a conventional magnetic disk.

FIG. 5 is a partially enlarged sectional view showing a conventional magnetic disk.

[Explanation of symbols]

 7 Lubrication layer

Claims (2)

[Claims] 1. A magnetic layer is formed on at least a substrate, a first solution prepared by diluting a fluorine-based lubricant with a volatile organic solvent is applied on the magnetic layer to form a lubricating layer, and then a fluorine-based lubricant is formed. A method of manufacturing a magnetic disk, wherein a lubricant is diluted with a volatile organic solvent, and a second solution having a concentration of a fluorine-based lubricant lower than that of the first solution is applied on the lubricating layer. . 2. The concentration of the fluorinated lubricant in the second solution is set to the first
The method for producing a magnetic disk according to claim 1, wherein the concentration of the fluorine-based lubricant in the solution is 10% to 20%.