JP2000357321A - Manufacturing method of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacture for surely removing contamination or abnormal protrusions that exist on the surface of a magnetic disk. SOLUTION: Through an air vent 7, gas is force-fed into or sucked from between a magnetic disk 1 and a pressure plate 2, thereby repeating contact and separation between the two. Thus, the contamination existing on the magnetic disk can be removed without fail by repeating the contact/separation between the magnetic disk and the pressure plate, so that a highly reliable magnetic disk can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic disk used in a hard disk drive.

[0002]

2. Description of the Related Art At present, a hard disk drive, which is a typical magnetic disk device, has a surface recording density of 1 Gb.
A device exceeding it / sqin has been commercialized, and a few years later, rapid technological progress has been recognized such that practical application of 10 Gbit / sqin will be discussed.

[0003] With the increase in recording density, there has been a demand for a reduction in the flying height of a floating magnetic slider with respect to a magnetic recording medium, and the possibility of disk / slider contact occurring for some reason during flying has increased. Under such circumstances, the recording medium is required to have higher smoothness.

However, in general, a magnetic disk has fine foreign matters and fine projections called "abnormal projections" on the surface after forming a protective film or after applying a lubricant. The surface is finished by removing the protrusion and reducing the height of the protrusion appropriately. Such an operation of removing abnormal protrusions and foreign matter on the disk surface by physical means is called "burnish".

For example, in a burnishing step using a polishing tape, basically, a polishing tape in which a grindstone such as alumina or diamond is provided on a flexible support with an organic binder is applied by applying an appropriate pressure to the magnetic disk surface. This is performed by bringing the disk and polishing tape into contact with each other.

As such a burnishing step, for example, in a manufacturing process of a magnetic disk medium, after processing the surface of the magnetic disk medium using a polishing tape, it is necessary to effectively remove only foreign matter and minute projections interposed on the surface. Japanese Patent Application Laid-Open No. 59-148134 and Japanese Patent Publication No. Hei 2-10486 disclose a method of manufacturing a magnetic disk medium using a polishing tape and a peripheral speed of the medium of 250 m / min or more and a tape processing pressure of 50 g / mm ² or less. Has been proposed.

[0007]

However, in burnishing using a polishing tape, if the abrasive grains of the polishing tape are not uniform and have a distribution (unevenness) in the grain size, the grain size is large. There has been a problem that the abrasive grains and the abrasive grains that have fallen off the tape damage the disk surface, cause an error, and lower the yield. Also, if polishing powder or grinding powder generated by polishing remains on the disk surface, it collides with the head and reduces the sliding durability, or damages the magnetic layer and the protective film. In addition, if abrasive powder or grinding powder remains on the disk surface, liquid lubricant and water are gathered around the remaining particles by capillary action, causing head adsorption.

[0008] These disks are excluded in the quality control test, but have the problem that the yield is reduced. Such a problem is not only a problem of burnishing using a polishing tape, but also applies to a case of using a polishing head or buff polishing, and a problem that polishing powder or grinding powder remains on a disk surface. Had.

[0009]

In order to solve the above-mentioned conventional problems, a method of manufacturing a magnetic disk according to the present invention comprises a slave having a ferromagnetic layer formed on a surface thereof and a slave having a ferromagnetic layer formed on the slave. A pressing plate for bringing the slave and the pressing plate into close contact with each other, and a separating means for separating the close contact between the slave and the pressing plate; The contact / separation is repeated a predetermined number of times by the means and the separating means.

As a result, the foreign matter remaining on the surface of the slave is transferred to the pressing plate side or discharged to the atmosphere by the separating means, so that the foreign matter can be reliably removed. Therefore, when the head slides on the slave surface, the sliding durability is not reduced, and the magnetic layer and the protective film are not damaged.

Further, according to a method of manufacturing a magnetic disk of the present invention, a slave having a ferromagnetic layer formed on its surface and a slave having the ferromagnetic layer formed thereon are brought into close contact with each other.
A pressing plate formed of a substrate having a higher hardness than the slave, a contacting unit for bringing the slave and the pressing plate into close contact with each other, and a separating unit for separating the contact state between the slave and the pressing plate. And the contact / separation is repeated a predetermined number of times by the contact means and the separation means.

As a result, the abnormal projections present on the surface of the magnetic disk can be reduced by deforming the shape, so that no polishing powder or grinding powder remains as in the prior art. Therefore, when the head slides on the slave surface, the sliding durability is not reduced, and the magnetic layer and the protective film are not damaged.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) A method for manufacturing a magnetic recording medium and a magnetic recording apparatus according to the present embodiment will be described with reference to FIGS.

FIG. 1 shows a chart of the process of this embodiment. As shown in FIG. 1, after forming a ferromagnetic layer on a glass magnetic disk, a lubricant is formed on the magnetic disk as a step 1, and a pressing plate is brought into close contact with / separated from the surface of the magnetic disk as a step 2. .

For example, as for the formation of a ferromagnetic layer, there is a step of providing a magnetic layer on a glass substrate by dry plating such as evaporation or sputtering. Further, usually, a method of protecting the magnetic layer by performing a step of providing a protective layer on the magnetic layer by dry plating such as vapor deposition or sputtering, or by dipping or spin coating is employed. Step 1 is a step of applying a lubricant by immersing the magnetic recording medium in a lubricant solution and then lifting the magnetic recording medium at a predetermined speed.

Next, the contents of the step 2 will be described in detail with reference to FIGS.

FIG. 2 is a sectional view of the apparatus showing a step 2 in the first embodiment, and particularly shows a separating means. FIG. 3 is a cross-sectional view of an apparatus showing a step 2 in the present embodiment, and particularly shows a contact unit. In FIG. 2, reference numeral 1 denotes a magnetic disk, that is, a slave, and reference numeral 2 denotes a silicon substrate, that is, a pressing plate, which is in close contact with the surface of the magnetic disk 1.

Reference numeral 3 denotes a contact surface of the pressing plate 2 with the magnetic disk 1, and the contact surface 3 is provided with a groove 4 radiating from the center of the pressing plate 2. FIG. 4 is a diagram showing the contact surface 3 of the pressing plate 2 with the magnetic disk 1. As shown in FIG. 4, the groove 4 extends radially from the center of the pressing plate 2. In this embodiment, the depth of the groove is set to about 5 μm. Reference numeral 5 denotes a boss arranged at the center of the pressing plate 2, which centers the magnetic disk 1 and the pressing plate 2 by fitting the boss into the inner peripheral hole of the magnetic disk 1. Further, a predetermined gap is provided between the inner peripheral hole of the magnetic disk 1 and the boss 5 so that air can flow. Reference numeral 6 denotes a support base for supporting the magnetic disk 1, and a vent hole 7 for flowing air is provided at the center. 8 is a pressing plate 2 and a magnetic disk 1
An air passage for discharging and pumping air between the air passages, 9 is an air outlet for discharging air from the air passage 8, 10 is a suction pump connected to the air outlet, and 11 is for controlling air discharge. It is an exhaust valve. Reference numeral 12 denotes an air supply pump for pumping air into the air passage 8, and reference numeral 13 denotes an air supply valve for controlling air supply. 0.01 μm
The air filter is provided so that foreign substances having a size of 0.01 μm or more are not fed to the air passage 8 by pressure. Reference numeral 14 denotes a holding arm for holding the pressing plate 2, and sucks the pressing plate 2 by sucking air from a through hole (not shown) provided in the holding arm 14.

First, the separating means will be described with reference to FIG. By operating the air supply pump 12 with the exhaust valve 11 closed and the air supply valve 13 opened, air flows into the air passage 8. Then, an arrow A in FIG.
Air is pumped upward as indicated by. As a result, the air fed to the ventilation hole 7 pushes the boss 5 upward, and the air is fed to the groove 4 as shown by the arrow B. The air pumped into the groove 4 spreads radially from the center of the pressing plate 2 to the outer periphery through the groove 4.

Then, the air further escapes from the groove 4 through the gap between the pressing plate 2 and the magnetic disk 1 to the outside of the magnetic disk. Due to the flow of the air, fine foreign matters adhering to the surface of the pressing plate 2 or the magnetic disk 1 are discharged to the atmosphere together with the air. At this time, it is preferable that the gap between the magnetic disk 1 and the pressing plate 2 is set as small as possible. In this embodiment, it is set to about 0.5 mm. As a result, the magnetic disk 1 and the pressing plate 2
Since the flow of air between the two becomes faster, fine foreign substances existing between the two can be reliably discharged to the atmosphere.
At this time, as shown in FIG.
The pressing plate 2 does not come off because it is configured not to be disengaged from the pressing plate 2. Thereafter, the pressure plate 2 is sucked to the holding arm 14 by sucking air from the through hole provided in the holding arm 14.

Next, the contact means will be described with reference to FIG. The air supply pump 12 is stopped, and the air supply valve 13 is closed. Then, by releasing the suction of the air attached to the holding arm 14, the pressing plate 2 is
Away from Then, the pressing plate 2 moves downward by gravity, and is placed on the magnetic disk 1 in a state where the boss 5 is fitted with the inner peripheral hole of the magnetic disk 1. At this time, the boss 5 aligns the magnetic disk with the inner peripheral hole of the magnetic disk 1 while positioning the magnetic disk, and also connects the space surrounded by the magnetic disk 1 and the pressing plate 2 with the ventilation hole 7 or the cutout. Having.

Thereafter, the exhaust valve 11 is opened and the exhaust pump 1
Activate 0. Then, as shown by the arrow C in FIG. 3, the air in the ventilation hole 7 is discharged downward, so that the air in the groove 4 is also discharged through the gap between the inner peripheral hole of the magnetic disk 1 and the boss 5. As a result, the pressure in the space of the groove 4 closed by the magnetic disk 1 becomes lower than the atmospheric pressure. Therefore, the magnetic disk 1 is pressed against the pressing plate 2 by the atmospheric pressure 15. As a result, foreign matter present on the magnetic disk 1 is interposed between the magnetic disk 1 and the pressing plate 2.

Next, the separating means shown in FIG. 2 is implemented again. That is, the exhaust valve 11 is closed, the air supply valve 13 is opened,
The air supply pump 12 is operated. Then, as shown by arrows A and B, the air is pressure-fed, and the pressing plate 2 moves upward by the force of the air pressure, and stops at the position where it comes into contact with the holding arm 14. At this time, as shown by the arrow B, the air is kept radially pumped from the center of the pressing plate 2 to the outer peripheral side through the groove 4.

As a result, foreign matter existing on the surface of the magnetic disk 1 is discharged to the atmosphere together with the air pumped from the suction pump 12 or transferred onto the contact surface 3 of the pressing plate 2.

This will be described with reference to FIG. FIG.
Shows the result of measuring the number of foreign substances present on the magnetic disk 1 before and after performing the step 2 by using an optical method.
(A) shows the state of foreign matter existing on the surface of the magnetic disk 1 before performing the step 2, and (b) shows the state of foreign matter existing on the surface of the magnetic disk 1 after performing the step 2. It is a result showing a state. In the figure, the places indicated by black dots are
This is the position where the foreign matter exists.

According to the results shown in FIG. 5, the number of foreign substances existing on the surface of the magnetic disk 1 before the step 2 was 15 but decreased to 0 after the step 2 was performed. I understand. This is because the hardness of the foreign matter present on the surface of the magnetic disk 1 is smaller than the hardness of the glass which is the substrate of the magnetic disk 1, so that when the magnetic disk 1 and the pressing plate 2 come into close contact with each other, the foreign matter It is thought that it was because he did not cut into the. As a result, when the magnetic disk 1 and the pressing plate 2 are separated from each other by the separating means, the foreign matter existing on the surface of the magnetic disk 1 adheres to the pressing plate 2 side or is fed from the air supply pump 12 by pressure. Will be discharged to the atmosphere together with the air. As a result, foreign substances present on the surface of the magnetic disk 1 are reliably removed.

As described above, according to the present embodiment, by bringing the magnetic disk 1 and the pressing plate 2 into close contact with or apart from each other, foreign substances existing on the surface of the magnetic disk 1 can be reliably removed. A highly reliable magnetic disk can be provided.

Although the burnishing step is not performed in this embodiment, for example, after the burnishing step using a tape, a head, a buffing abrasive, or the like is performed,
The same effect can be obtained even if a method of removing the polishing powder or the grinding powder remaining on the surface of the magnetic disk 1 in the step 2 is adopted.

The order of Step 1 and Step 2 is not limited to this, and a lubricant may be applied to the magnetic disk after the step of closely contacting / separating the magnetic disk 1 from the pressing plate 2. An equivalent effect can be obtained.

FIG. 4 shows the shape of the groove 4 of the pressing plate 2.
In the inner peripheral side and the outer peripheral side of the pressing plate 2, the width is the same. However, if the width is increased toward the outer peripheral side, the area pressed by the atmospheric pressure increases, and the inner peripheral side to the outer peripheral side increases. More uniform contact can be achieved over the entire area.

In the present embodiment, an example in which the close / separate operation is performed once has been described. For example, the close / separate operation is performed a plurality of times while changing the circumferential phase between the magnetic disk 1 and the pressing plate 2. Accordingly, a method of more reliably removing foreign matter may be adopted. (Embodiment 2) A method for manufacturing a magnetic recording medium and a magnetic recording apparatus according to Embodiment 2 will be described with reference to FIG.

Each step is the same as in the first embodiment.

First, a ferromagnetic layer is formed on the magnetic disk 1, a lubricant is formed on the magnetic disk in step 1, and a pressing plate 2 is brought into close contact with and separated from the magnetic disk 1 in step 2.

The difference from the first embodiment is the material of the substrate of the magnetic disk 1, and the second embodiment uses aluminum.

That is, since the material of the magnetic disk 1 is aluminum and the material of the pressing plate 2 is silicon, the pressing plate 2 has a higher hardness. Therefore, when the magnetic disk 1 and the pressing plate 2 come into contact with each other, the abnormal projections existing on the surface of the magnetic disk 1 are crushed by the pressing plate 2 having a higher hardness than aluminum. This will be described with reference to FIG. FIG. 6 shows the result of measuring the surface state of the magnetic disk 1 before and after performing the step 2 by using an optical method. FIG. 4A shows the surface condition of the magnetic disk 1 before the step 2 is performed, and FIG. 4B shows the surface condition of the magnetic disk 1 after the step 2 is performed.

From the results shown in FIG. 6, it can be seen that the surface state of the magnetic disk 1 before the step 2 is rough, but the surface state after the step 2 is smooth. This is because, due to the contact between the magnetic disk 1 and the pressing plate 2, the tip of the abnormal protrusion on the side of the magnetic disk 1 having low hardness is deformed and crushed.

This method employs a method of changing the shape instead of shaving abnormal projections as in the conventional burnishing process, so that shavings and abrasive grains do not remain on the surface of the magnetic disk. .

As described above, in this embodiment, the hardness of the magnetic disk 1 is made lower than the hardness of the pressing plate 2 and the two are brought into close contact with or separated from each other, so that the height of the abnormal projections existing on the magnetic disk 1 is increased. Can be reliably reduced, so that a highly reliable magnetic disk having a smooth surface can be provided.

In this embodiment, an example in which the close / separate operation is performed once has been described. For example, the close / separate operation is performed a plurality of times while changing the phase between the magnetic disk 1 and the pressing plate 2. A method of more reliably smoothing the surface may be employed.

[0040]

As described above, according to the present invention, by bringing the magnetic disk and the pressing plate into close contact with or apart from each other, foreign substances existing on the magnetic disk can be reliably removed.
A highly reliable magnetic disk can be provided.

Further, by making the hardness of the magnetic disk smaller than the hardness of the pressing plate, and by closely contacting / separating the two, the height of abnormal protrusions existing on the magnetic disk can be reliably reduced. A highly reliable magnetic disk can be provided.

[Brief description of the drawings]

FIG. 1 is a chart of a process according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an apparatus for performing the contacting step (step 2).

FIG. 3 is a sectional view of an apparatus for performing the contacting step (step 2).

FIG. 4 is an external view of a contact surface of a pressing plate for performing the contacting step (step 2).

FIG. 5 is a view showing the result of measuring the number of foreign substances present on the magnetic disk before and after performing the same step 2 by using an optical method;

FIG. 6 is a diagram showing a result of measuring a surface state existing on a magnetic disk using an optical method before and after performing a step 2 in the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic disk 2 ... Press plate 4 ... Groove 8 ... Air passage 10 ... Exhaust pump 11 ... Exhaust valve 12 ... Air supply pump 13 ... Air supply valve

Claims (5)

[Claims] 1. A slave having a ferromagnetic layer formed on a surface thereof, a pressing plate for bringing the slave into close contact with the surface of the slave, and a contact unit for bringing the slave into contact with the pressing plate;
A method for manufacturing a magnetic recording medium, comprising: separating means for separating a contact state between the slave and the pressing plate; and repeating contact / separation a predetermined number of times by the contact means and the separating means. 2. The method according to claim 1, wherein the slave is formed of a glass substrate. 3. The method according to claim 1, wherein the pressing plate is formed of a substrate having higher hardness than the slave. 4. The contact means exhausts gas existing between the slave and the pressing plate through a concave portion or a through hole provided in the pressing plate in a state where the slave and the pressing plate are in contact with each other. 4. The method of manufacturing a magnetic recording medium according to claim 1, wherein the slave is brought into close contact with the pressing plate. 5. The separating means separates the slave from the pressing plate by forcing gas between the slave and the pressing plate through a recess or a through hole provided in the pressing plate. 4. The method for manufacturing a magnetic recording medium according to claim 1, wherein: