JPH10255256A - Magnetic disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk having an improved durability by reducing contact between the disk and a head upon the retraction of the head in a zone texture recording medium. SOLUTION: A stepped portion 19 is provided between a data zone 17 and a CSS zone 18 so that the CSS zone 18 is positioned at a lower level than the data zone 17. Laser bumps 12 are formed in the CSS zone 18 so that a height h6 of the top of each bump is set at a level equal to or slightly lower than a height hS of the data zone. Since the height of the CSS zone 18 is set at a level equal to or lower than the height of the data zone 17, a head can smoothly move over a border portion 19 between the data zone 17 and the CSS zone 18 even when an amount of head floating is reduced. Thus, contact between the head and the laser bump 12 upon the retraction is reduced, resulting in satisfactory reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic disk mounted on a magnetic disk device used for an external storage device of a computer.

[0002]

2. Description of the Related Art In a magnetic disk drive, a magnetic disk, which is a recording medium, starts to rotate at the time of start-up. Writing and reading of magnetic recording are performed while maintaining a certain clearance between the disk and the magnetic disk, that is, the flying height. When the magnetic disk stops, the flying height of the head decreases as the rotational speed of the magnetic disk decreases, and finally, the head slides and stops. This is widely called as a contact start stop (CSS) method.

A magnetic disk is formed by forming concentric grooves called textures on an aluminum substrate subjected to Ni-P plating.
Alternatively, a groove which crosses the grooves at an angle is provided, and an underlayer Cr film, a Co alloy magnetic film and a carbon protective film formed by a sputtering method are formed thereon, and a liquid lubricating film is generally formed on the uppermost surface. Structure. Some small-diameter disks having a size of 2.5 inches or less employ a glass substrate having excellent impact resistance instead of an aluminum substrate. The carbon protective film and the lubricating film are provided to suppress wear due to sliding between the head and the magnetic disk, and the texture is applied for the purpose of reducing the attraction force generated between the head and the magnetic disk when the magnetic disk device is stopped. .

In order to achieve the high recording density required for increasing the capacity of a magnetic disk drive, the head has been lowered in addition to the characteristics of a magnetic circuit, a servo circuit, a head, and a magnetic disk. To achieve low flying of the head, it is necessary to smooth the surface of the magnetic disk, but this also increases the attraction force of the head. Therefore, the difficulty of designing a magnetic disk that satisfies these conflicting characteristics is increasing.

In addition, as the flying height of the head decreases, the probability that the head comes into contact with the surface of the storage medium due to the inclination of the head or the like during the operation of moving the head to a predetermined storage medium position (hereinafter referred to as seek) also increases. Therefore, durability during head seek is also regarded as important.

Recently, a zone texture storage medium has been proposed as a storage medium that achieves both the surface smoothness characteristics (hereinafter referred to as glide characteristics) and the adsorption characteristics of the magnetic disk. This is a recording medium in which the surface of a magnetic disk, which is a storage medium, is divided into regions where glide characteristics and adsorption characteristics are required, and the surface shapes of different magnetic disks are designed. That is, an area (hereinafter referred to as a data zone) where magnetic recording requiring glide characteristics is performed is finished to a smooth surface, and an area (hereinafter a CSS zone) where a head is held when a magnetic disk device that requires suction characteristics is stopped (hereinafter a CSS zone). (Hereinafter referred to as a recording medium) having a surface having a predetermined surface roughness. A mechanical zone texture recording medium (for example, Japanese Unexamined Patent Publication No. 8-194951) in which a surface roughness is mechanically imparted by a polishing method using a polishing tape or abrasive grains by a processing method of a CSS zone, or a substrate by laser light irradiation Laser zone texture recording medium provided with dot-shaped bumps due to thermal deformation (for example, US Patent 51057)
81) are disclosed.

[0007]

However, in a magnetic disk drive equipped with a zone texture recording medium, when the head moves from the outer periphery to the CSS zone when the power is turned off (hereinafter referred to as retract), the flying height of the head is extremely low. If the mechanical texture is too low, the head may disturb the flying attitude at the step and contact the disc, or the laser texture may cause the head to contact the bump, and the repetition of this will damage the recording medium or the head. There is a problem of how to improve durability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic disk in which the contact between the head and the disk at the time of head retraction in a zone texture recording medium is reduced and the durability is improved.

[0009]

According to the magnetic disk of the present invention, a data zone in which an underlayer, a magnetic layer, a protective layer, and a lubricating layer are laminated on a surface of a non-magnetic substrate and data is written;
In a magnetic disk having a CSS (contact start / stop) zone with which the head comes in contact, a region of the CSS zone provided annularly at a predetermined position on the surface of the non-magnetic substrate has a predetermined step relative to a region of the data zone. , And a plurality of dot-shaped bumps are provided in a predetermined arrangement in the CSS zone area.

The dot-shaped bump may be a bump formed by irradiating a laser beam.

It is preferable that the height of the dot-shaped bump is not more than the size of the step.

That is, a step is provided between the data zone and the CSS zone, the CSS zone is made lower than the data zone,
A laser bump is formed thereon, and the height of the CSS zone bump top is made equal to or slightly lower than the data zone height position.

Since the heights of the data zone and the CSS zone are set to be equal or slightly lower, the head can smoothly move on the boundary between the data zone and the CSS zone even when the flying height of the head is reduced. The contact between the head and the laser bump can be reduced, and good reliability can be obtained.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially enlarged sectional view showing an inner peripheral portion of a magnetic disk according to an embodiment of the present invention.
In the figure, reference numeral 11 denotes a Ni-P aluminum substrate, 12 denotes a laser bump, 17 denotes a data zone, 18 denotes a CSS zone, and 19 denotes a step. FIG. 2 is a schematic cross-sectional view showing the film configuration of a magnetic disk. In the figure, reference numeral 20 denotes a magnetic disk, 21 denotes an aluminum substrate having a NiP film (hereinafter referred to as Ni-P aluminum substrate), 23 denotes a base film, and 24 denotes a base film. Is a magnetic film, 25 is a protective film, and 26 is a lubricating film.

As shown in FIG. 1, the magnetic disk of the present invention has a data zone 17 on the surface of a Ni--P aluminum
It has a step 19 at the boundary with the SS zone 18,
The laser bump 12 is provided in the zone, and the height of the top of the laser bump from the surface of the CSS zone 18 is almost the same as or slightly lower than the height of the difference portion 19.

The surface of the Ni-P aluminum substrate 11 is mechanically polished with a polishing tape to a CSS zone 18 in an inner peripheral region from a desired radial position, and only a step portion 19 is formed from a data zone 17 which is not mechanically polished. It is processed to be low. The level difference h _S between the polishing region and the data zone (hereinafter referred to as a polishing level difference) is preferably 5 nm to 25 nm. Then, a bump 1 having a height h _b by irradiating a laser beam onto the polishing area is formed.
2 are formed. The height h _{b of the} bump is the polishing step h _S
A height smaller than 0 to 5 nm is desirable.

After these processes, as shown in FIG.
Base film 1 by sputtering on Ni-P aluminum substrate 11
3. The magnetic film 14 and the protective film 15 are formed, and the lubricating film 16 is applied to the outermost surface, thereby completing the structure of the magnetic disk 20.

[0018]

Next, an embodiment of the present invention will be described in detail with reference to FIGS. Radius of surface of Ni-P aluminum substrate 11 for 2.5 inch size magnetic disk 1
From 9.5 mm, the inner peripheral portion was polished with a polishing tape impregnated with polishing abrasive grains to form a CSS zone 18 having a polishing step of 12 nm. Polishing is performed in two stages, and the surface roughness Ra =
Finished to 1.5 nm. The bump to be applied to the polished area is irradiated with a CW oscillation laser having a wavelength of 0.53 μm,
It was formed at a pitch of × 20 μm and a height of 10 nm. The bump height was set smaller than the polishing step in consideration of the respective tolerances of the polishing step and the laser bump height.

Then, DC is placed on the Ni--P aluminum substrate 21.
50 nm of Cr underlayer 23 by magnetron sputtering
An oCrTa magnetic film 24 is formed in order of 20 nm and a carbon protective film 25 is formed in order of 10 nm, and Fomblin Z-DO manufactured by Montefluos (Italy) is formed thereon by dipping.
An L lubricating film 26 was formed to a thickness of 1.5 nm.

In order to confirm the performance of the magnetic disk of the present invention, a comparative example corresponding to the above-described embodiment was provided and compared with the embodiment. Two types of comparative examples were prepared. Comparative example 1 has a structure corresponding to the above-described conventional mechanical zone texture magnetic disk manufactured in the same manner as in example 1 except for laser bump processing, and comparative example 2 excludes mechanical polishing. This is a structure corresponding to the above-described conventional laser zone texture magnetic disk manufactured in the same manner as in Example 1.

FIG. 3 is a partially enlarged cross-sectional view of a mechanical zone texture magnetic disk of Comparative Example 1 corresponding to the conventional example. In FIG. 3, reference numeral 31 denotes a Ni-P aluminum substrate, 37 denotes a data zone, and 38 denotes a CSS zone. FIG. 4 is a partially enlarged cross-sectional view of a laser zone texture magnetic disk of Comparative Example 2 corresponding to the conventional example, in which 41 is a Ni-P aluminum substrate, 42 is a laser bump, 47 is a data zone, 48
Is a CSS zone.

Table 1 is a comparison table comparing the results of the seek test between the magnetic disk of the embodiment and the magnetic disks of Comparative Examples 1 and 2 corresponding to the conventional example.

[0023]

[Table 1] Under the conditions of 65 ° C.-70% environment and a disk rotation speed of 7200 rpm, 100 between the CSS zone and the outermost periphery of the data zone.
Ten thousand seek tests were performed, and the amount of deposits on the head after the test was investigated. The test included a flying height of 15 nm, a 30% slider, and an ABS (Air Bearing Surfac).
e) Using a head with carbon coating and a weight of 2 gf, the seek was performed in a radius of 18.5 mm to 22 mm.

As can be seen from Table 1, the amount of deposits on the head of the embodiment of the present invention is smaller than that of the comparative example corresponding to the conventional example.
It can be understood that the magnetic disk of the present invention has the effect of improving the durability during retraction.

[0025]

As described above, the magnetic disk of the present invention has the effect of improving the durability of the magnetic disk drive. .

The reason is that compared to the surface of the data zone, C
Since the height of the surface of the SS zone is set to be the same or slightly lower, the head can move smoothly on the boundary between the data zone and the CSS zone even when the flying height of the head is low. This is because the contact of the substrate can be reduced, and good reliability characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view showing an inner peripheral portion of a magnetic disk according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a film configuration of a magnetic disk.

FIG. 3 is a partially enlarged cross-sectional view of a mechanical zone texture magnetic disk of Comparative Example 1 corresponding to a conventional example.

FIG. 4 is a partially enlarged sectional view of a laser zone texture magnetic disk of Comparative Example 2 corresponding to the conventional example.

[Explanation of symbols]

 11, 21, 31, 41 Ni-P aluminum substrate 12, 42 Laser bump 17, 37, 47 Data zone 18, 38, 48 CSS zone 19 Stepped portion 20 Magnetic disk 23 Base film 24 Magnetic film 25 Protective film 26 Lubricating film

Claims (3)

[Claims] An underlayer, a magnetic layer, a protective layer, and a lubricating layer are laminated on a surface of a non-magnetic substrate, and have a data zone in which data is written and a CSS (contact start / stop) zone in which a head contacts. In the disc, a region of the CSS zone annularly provided at a predetermined position on the surface of the nonmagnetic substrate is formed lower than the data zone by a predetermined step, and a predetermined region is formed in the CSS zone region. A magnetic disk, wherein a plurality of dot-shaped bumps are provided in an arrangement. 2. The magnetic disk according to claim 1, wherein the dot-shaped bump is a bump formed by irradiating a laser beam. 3. The magnetic disk according to claim 1, wherein a height of the dot-shaped bump is equal to or less than a size of the step.