JP2002170230A - Magnetic transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it easy to separate a slave medium from a master carrier after magnetic transfer is performed and to prevent the adsorption of dust to the slave medium, in a magnetic transfer method by which the magnetic transfer of an information signal like a servo signal from the master carrier to the slave medium is performed. SOLUTION: When the master carrier 3 carrying the information signal and the slave medium 2 having a lubricating layer formed on its recording surface in the practical use condition are brought into contact with each other and an electric field for transfer is applied to them to perform the magnetic transfer, the slave medium 2 before the lubricating layer is formed and the master carrier 3 are brought into contact with each other to perform the magnetic transfer and thereby an increase in adhesion due to the existence of the lubricating layer and the adsorption of the dust are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic transfer method for magnetically transferring information from a master carrier carrying information to a slave medium.

[0002]

2. Description of the Related Art A magnetic transfer method transfers a magnetic pattern corresponding to information (for example, a servo signal) carried on a master carrier by applying a transfer magnetic field while the master carrier and the slave medium are in close contact with each other. It is. Examples of the magnetic transfer method include JP-A-63-183623, JP-A-10-40544, and JP-A-10-26.
No. 9566, and the like.

Further, in a hard disk, a high recording density flexible disk, etc. as a slave medium,
A lubricating layer is formed on the surface of the magnetic recording layer from the viewpoint of reducing friction against contact with the magnetic head in use.

[0004]

By the way, at the time of magnetic transfer by the above magnetic transfer method, if the lubricating layer is formed on the recording surface of the slave medium as described above, the magnetic transfer is performed in close contact with the master carrier. Later, it may be difficult to peel off the slave medium from the master carrier. Further, dust adhering to the master carrier may adhere to the slave medium after the adhesion, and may cause an increase in an error rate during recording and reproduction in an actual use state.

As a result of analysis of the slave medium after the magnetic transfer, it was found that the meniscus of the lubricating layer coated on the recording surface increased the adhesion between the slave medium and the master carrier. It was also found that the lubricating layer was adsorbing dust adhering to the master carrier. Such a phenomenon has been particularly noticeable in a slave medium having a metal thin-film type magnetic recording layer.

[0006] If the adhesion between the slave medium and the master carrier is high, it is difficult to separate the slave medium from the master carrier after the magnetic transfer. May be damaged. If dust from the magnetic transfer is adsorbed on the lubricating layer of the slave medium, its adhesion is so strong that it is difficult to remove it by post-processing.Dust collides with the magnetic head as the slave medium rotates at high speed. This causes a head crash or a dropout, which causes an increase in the error occurrence rate.

The present invention has been made in view of such a problem, and a magnetic transfer method for facilitating separation of a slave medium from a master carrier after magnetic transfer and preventing dust from being attracted to the slave medium. The purpose is to provide.

[0008]

According to the magnetic transfer method of the present invention, a master carrier carrying an information signal is brought into close contact with a slave medium having a lubricating layer formed on the surface of a recording surface in use. In the magnetic transfer method for performing magnetic transfer by applying a magnetic field for use, the magnetic transfer is performed by bringing the slave medium and the master carrier in close contact with each other before the lubricant layer is formed.

A lubricating layer is formed on the recording surface of the slave medium after the magnetic transfer to reduce friction with the magnetic head in use.

Before the slave medium is brought into close contact with the master carrier, a cleaning process for removing minute projections or attached dust on the surface is performed as necessary. On the other hand, before the master carrier is brought into close contact with the slave medium, a cleaning process for removing attached dust is performed as necessary.

There is a case where the master carrier is brought into close contact with one side of the slave medium to perform the one-sided sequential transfer, and a case where the master carrier is brought into close contact with both sides of the slave medium to perform the simultaneous double-sided transfer. The slave medium is preferably a hard disk, and is also applicable to a flexible disk. As the magnetic field generating means for applying the transfer magnetic field, an electromagnet device or a permanent magnet device is adopted, and the transfer magnetic field is applied in the track direction from one or both sides of the contact portion between the master carrier and the slave medium while relatively rotating. I do.

In the magnetic transfer method, a master medium is first provided with initial magnetization in which a slave medium is DC-magnetized in the track direction, and a magnetic layer is formed on the slave medium and a fine uneven pattern corresponding to information to be transferred. And magnetic transfer by applying a transfer magnetic field in a direction substantially opposite to the initial DC magnetization direction of the slave medium surface. The information is preferably a servo signal.

[0013]

According to the present invention as described above, the slave medium and the master carrier before the lubricating layer is formed on the surface are brought into close contact with each other to perform magnetic transfer, so that the adhesive force is increased by the meniscus of the lubricating layer. Thus, the slave medium can be easily peeled off after the magnetic transfer, the workability can be improved, the slave medium can be prevented from being damaged, and the life of the master carrier can be extended.

Further, dust adhering to the master carrier at the time of close contact is not adsorbed to the lubricating layer of the slave medium, so that an increase in error rate can be suppressed and reliability can be improved.

[0015]

Embodiments of the present invention will be described below in detail. FIG. 1 is a diagram showing a transfer state of a magnetic transfer method according to one embodiment of the present invention. FIG. 2 is a diagram showing a basic process of magnetic transfer. Each drawing is a schematic diagram, and the thickness and the like are shown in proportions different from actual dimensions.

In FIG. 1, at the time of magnetic transfer, the magnetic recording surface of the slave medium 2 in a state where no lubricating layer is formed on the surface is brought into contact with the information carrying surface of the master carrier 3 and is brought into close contact with a predetermined pressing force. In a state where the master carrier 3 and the slave medium 2 are in close contact with each other, a magnetic field for transfer is applied by the magnetic field generating means 5 to magnetically transfer and record information such as servo signals.

The slave medium 2 is preferably a hard disk having a magnetic recording layer formed on both surfaces. Before the slave medium 2 is brought into close contact with the master carrier 3, a cleaning process for removing minute projections or attached dust on the surface with a glide head, a polishing body or the like is performed. Applied as needed. The present invention is preferably applied to magnetic transfer to a flexible disk, particularly to a disk having a metal thin film type magnetic recording layer.

The master carrier 3 is formed in a disk shape,
One surface thereof has a transfer information carrying surface formed by a fine uneven pattern (to be described later with reference to FIG. 2). There is a case where the master carrier 3 is brought into close contact with one surface of the slave medium 2 to perform one-side sequential transfer, and a case where the master carrier 3 is brought into close contact with both surfaces of the slave medium 2 to perform simultaneous double-side transfer. Before the master carrier 3 is brought into close contact with the slave medium 2, a cleaning process for removing attached dust is performed as necessary.

The magnetic field generating means 5 for applying a transfer magnetic field includes:
An electromagnet device that generates a magnetic field line parallel to the track direction (tangential direction of the circumferential track) by winding a coil 53 around a core 52 having a gap 51 extending in the radial direction of the master carrier 3 held by the close contact means, or a similar magnetic field line The permanent magnet device that generates the above is disposed on one side or both sides. When a magnetic field is applied, a transfer magnetic field is applied by the magnetic field generating means 5 while rotating the slave medium 2 and the master carrier 3 integrally, and the transfer information of the master carrier 3 is magnetically transferred and recorded on the recording surface of the slave medium 2. The magnetic field generating means 5 may be provided so as to rotate.

After the magnetic transfer is completed, the close contact between the slave medium 2 and the master carrier 3 is released, and the slave medium 2
Is separated from the master carrier 3 and discharged. On the surface of the recording surface of the slave medium 2 after the magnetic transfer, a solution containing a lubricant (for example, silicon oil) is evenly applied by dip coating, spin coating, bar coating or the like, and dried to form a lubricating layer. Formed.

According to the above-described embodiment, since the lubricating layer is not formed on the surface of the slave medium 2 during magnetic transfer, there is no increase in the adhesive force with the master carrier 3, so that the weight is light. The slave medium 2 and the master carrier 3 can be separated by force, so that the workability is improved, the slave medium 2 is prevented from being damaged, and the life of the master carrier 3 is extended. In addition, the dust adhering to the master carrier 3 is not attracted during the close contact, and the dust adhering to the slave medium after the magnetic transfer is reduced and can be removed by post-processing. In addition, reliability can be improved.

FIG. 2 is a diagram showing a basic mode of magnetic transfer. (a) shows a case where a magnetic field is applied in one direction and the slave medium 2 is applied.
Is a step of applying a magnetic field in the opposite direction by bringing the master carrier 3 and the slave medium 2 into close contact with each other, and (c) is a view showing a state after magnetic transfer.

First, as shown in FIG. 2A, an initial magnetic field Hin is applied to the slave medium 2 in one direction in the track direction to perform initial magnetization (DC demagnetization) in advance. Thereafter, as shown in FIG. 2 (b), the magnetic transfer surface of the slave medium 2 is brought into close contact with the information carrying surface of the master carrier 3 in which the magnetic layer 32 is coated on the fine uneven pattern of the substrate 31. The magnetic transfer is performed by applying a transfer magnetic field Hdu in the track direction 2 in a direction opposite to the initial magnetic field Hin. As a result, FIG.
As shown in (1), information according to the pattern of the formation of the contact projections and recesses of the magnetic layer 32 on the information carrying surface of the master carrier 3 is magnetically transferred and recorded on the magnetic recording surface (track) of the slave medium 2. You.

It should be noted that even if the concave / convex pattern of the substrate 31 of the master carrier 3 is a negative pattern having a concave / convex shape reverse to the positive pattern of FIG. 2, the direction of the initial magnetic field Hin and the direction of the transfer magnetic field Hdu are set to By reversing the direction, similar information can be magnetically transferred and recorded.

When the substrate 31 is made of a ferromagnetic material such as Ni, magnetic transfer can be performed only with the substrate 31 and the magnetic layer 32 (soft magnetic layer) does not need to be covered. By providing the layer 32, better magnetic transfer can be performed. When the substrate 31 is a non-magnetic material, it is necessary to provide the magnetic layer 32.

When the magnetic layer 32 is coated on the substrate 31 made of a ferromagnetic metal, the influence of the magnetism of the substrate 31 is cut off.
It is preferable to provide a non-magnetic layer between the substrate 31 and the magnetic layer 32. Further, the uppermost layer is coated with a protective film such as diamond-like carbon (DLC), and this protective film improves contact durability and enables magnetic transfer many times. DLC
An Si film may be formed below the protective film by sputtering or the like.

The master carrier 3 will be described. As the substrate 31 of the master carrier 3, nickel, silicon, quartz plate, glass, aluminum, alloy, ceramics, synthetic resin, or the like is used. The formation of the concavo-convex pattern is performed by a stamper method, a photofabrication method, or the like.

In the stamper method, a photoresist is formed on a glass plate (or quartz plate) having a smooth surface by spin coating or the like, and a laser beam (or a laser beam) modulated according to a servo signal while rotating the glass plate is formed. An electron beam (electron beam) is applied to expose a predetermined pattern on the entire surface of the photoresist, for example, a pattern corresponding to a servo signal extending linearly in the radial direction from the center of rotation to each track on a portion corresponding to each frame on the circumference. Thereafter, the photoresist is developed and the exposed portions are removed to obtain a master having an uneven shape due to the photoresist. Next, based on the concave / convex pattern on the surface of the master, plating (electroforming) is performed on the surface to form a Ni substrate having a positive concave / convex pattern, and the Ni substrate is separated from the master. This substrate is used as a master carrier as it is, or a non-magnetic layer, a soft magnetic layer, and a protective film are coated on the concavo-convex pattern as needed to obtain a master carrier.

Further, a plating is performed on the master to form a second master, and plating is performed using the second master.
A substrate having a negative concavo-convex pattern may be produced. Further, a second master may be plated or pressed with a resin solution and cured to form a third master, and the third master may be plated to form a substrate having a positive concavo-convex pattern. .

On the other hand, after forming a pattern with a photoresist on the glass plate, etching is performed to form a hole in the glass plate, and a master from which the photoresist has been removed is obtained. Thereafter, a substrate is formed in the same manner as described above. You may.

As the material of the substrate made of metal, Ni or Ni alloy can be used. The plating for forming this substrate is performed by various kinds of metal film formation including electroless plating, electroforming, sputtering, and ion plating. Law is applicable. Depth of uneven pattern on substrate (height of protrusion)
Is preferably in the range of 80 nm to 800 nm, more preferably 150 nm to 600 nm. This concavo-convex pattern is formed long in the radial direction in the case of a servo signal.
For example, the length in the radial direction is preferably from 0.3 to 20 μm, and the length in the circumferential direction is preferably from 0.2 to 5 μm. It is preferable to select a pattern that is longer in the radial direction in this range as a pattern carrying servo signal information. .

The magnetic layer 32 (soft magnetic layer) is formed by depositing a magnetic material by vacuum deposition such as vacuum deposition, sputtering, or ion plating, or by plating. As the magnetic material of the magnetic layer, Co, a Co alloy (C
oNi, CoNiZr, CoNbTaZr, etc.), Fe,
Fe alloys (FeCo, FeCoNi, FeNiMo, F
eAlSi, FeAl, FeTaN), Ni, and Ni alloy (NiFe) can be used. Particularly preferably, F
eCo and FeCoNi. The thickness of the magnetic layer is 50n
m to 500 nm, more preferably 1 to 500 nm.
It is 50 nm to 400 nm. The material of the nonmagnetic layer provided as an underlayer below the magnetic layer may be Cr, CrT
i, CoCr, CrTa, CrMo, NiAl, Ru,
C, Ti, Al, Mo, W, Ta, Nb and the like are used. This nonmagnetic layer can suppress deterioration of signal quality when the substrate is a ferromagnetic material.

Preferably, a protective film such as DLC is provided on the magnetic layer, and a lubricant layer may be provided. More preferably, a DLC film of 5 to 30 nm and a lubricant layer are present as a protective film. Further, an adhesion strengthening layer such as Si may be provided between the magnetic layer and the protective film. The lubricant is used to compensate for the displacement that occurs during the contact process with the slave medium.
Improves durability deterioration such as generation of scratches due to friction.

A master substrate may be prepared by preparing a resin substrate using the master and providing a magnetic layer on the surface of the resin substrate. As a resin material for the resin substrate, an acrylic resin such as polycarbonate / polymethyl methacrylate, a vinyl chloride resin such as polyvinyl chloride / vinyl chloride copolymer, an epoxy resin, an amorphous polyolefin, and a polyester can be used. Polycarbonate is preferred in terms of moisture resistance, dimensional stability, cost, and the like. If there are burrs on the molded product, they are removed by varnish or polish. Alternatively, the master may be formed by spin coating or bar coating using an ultraviolet curable resin, an electron beam curable resin, or the like. The height of the pattern protrusion of the resin substrate is 50 to
The range of 1000 nm is preferred, more preferably 20 nm.
The range is from 0 to 500 nm.

A master layer is obtained by coating a magnetic layer on the fine pattern on the surface of the resin substrate. The formation of the magnetic layer
The magnetic material is formed by a vacuum film forming method such as a vacuum evaporation method, a sputtering method, or an ion plating method, or a plating method.

On the other hand, in the photofabrication method, for example, a photoresist is applied to a smooth surface of a flat substrate, and exposure and development using a photomask corresponding to a servo signal pattern are performed. Form a pattern. Next, in the etching step, the substrate is etched according to the pattern, and a hole having a depth corresponding to the thickness of the magnetic layer is formed. Next, a vacuum deposition method of a magnetic material,
A magnetic material is formed to a thickness corresponding to the formed holes by a vacuum film forming means such as a sputtering method or an ion plating method or a plating method to the surface of the substrate. Next, the photoresist is removed by a lift-off method, and the surface is polished to remove any burrs and to smooth the surface.

The slave medium 2 will be described. As a slave medium, a coating type magnetic recording medium or a metal thin film type magnetic recording medium is used. Commercially available media such as high-density flexible disks are examples of the coating type magnetic recording media. Regarding the metal thin-film type magnetic recording medium, first, Co, a Co alloy (CoPtCr, CoCr, C
oPtCrTa, CoPtCrNbTa, CoCrB,
CoNi, etc.), Fe, Fe alloys (FeCo, FePt,
FeCoNi) can be used. It is preferable that the magnetic flux density is large and that the magnetic recording medium has magnetic anisotropy in the same direction as the slave medium (in-plane direction for in-plane recording, perpendicular direction for perpendicular) because clear transfer can be performed. It is preferable to provide a non-magnetic underlayer under the magnetic material (on the side of the support) to provide the necessary magnetic anisotropy. It is necessary to match the crystal structure and lattice constant to the magnetic layer. For that purpose, Cr, CrTi, CoCr, CrTa, CrM
o, NiAl, Ru or the like is used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a magnetic transfer method according to an embodiment of the present invention.

FIG. 2 is a diagram showing basic steps of a magnetic transfer method according to an embodiment of the present invention.

[Explanation of symbols]

 2 slave medium 3 master carrier 5 magnetic field generating means

Claims (1)

[Claims] 1. A master carrier carrying an information signal,
In a use state, in a magnetic transfer method in which a slave medium having a lubricating layer formed on the surface of a recording surface is brought into close contact and a transfer magnetic field is applied to perform magnetic transfer, the slave medium before the lubricating layer is formed A magnetic transfer method, wherein magnetic transfer is performed by closely adhering to a master carrier.