JP2002251722A - Master carrier for magnetic transfer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out magnetic transfer to much more slave media by prolonging the life of a master carrier for magnetic transfer, and to prevent the signal omission of magnetic information transferred to the slave media by magnetic transfer. SOLUTION: Fine recessed and projected parts 15 are formed by texturing the projected surface of a substrate 13 having recessed and projected patterns according to information to be transferred. Thus, a master carrier 11 having a rough surface 17 on the projected part surface of a soft magnetic layer 16 formed on the substrate 13 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic transfer master carrier provided with an uneven pattern for transferring information to a slave medium.

[0002]

2. Description of the Related Art In general, as the amount of information increases, a so-called high-speed access capable of reading a required portion in a large capacity, inexpensive, and preferably in a short period of time in accordance with an increase in the amount of information has been developed. A possible medium is desired. For example, high-density magnetic disk media used for hard disk devices and floppy (registered trademark) disk devices are known.
The magnetic head scans a narrow track width accurately and has a high S /
A so-called tracking servo technique for reproducing a signal at the N ratio plays a large role. In one round of the disk, tracking servo signals, address information signals, reproduced clock signals, and the like are recorded at a certain interval as a so-called preformat.

[0003] The magnetic head is set so that it can run on the track accurately by reading such a preformat signal and correcting its own position. The current preformat is created by recording disks one by one or one track at a time using a dedicated servo recording device.

[0004] However, the servo recording device is expensive, and it takes time to create a preformat.
This process occupies a large part of the manufacturing cost, and it is desired to reduce the cost.

On the other hand, there has been proposed a method of realizing the preformat by magnetic transfer instead of recording the preformat one track at a time. For example, Japanese Patent Application Laid-Open No. 10-45544
And Japanese Patent Application Laid-Open No. H10-269566 introduce a magnetic transfer technique. This magnetic transfer is performed by preparing a master carrier having a concavo-convex pattern corresponding to information to be transferred to a slave medium such as a magnetic disk medium, which is a magnetic transfer medium, and transferring the master carrier in close contact with the slave medium. By applying a magnetic field for use, a magnetic pattern corresponding to information (for example, a servo signal) carried by the concavo-convex pattern of the master carrier is transferred to a slave medium.
Recording can be performed statically without changing the relative position between the master carrier and the slave medium, accurate preformat recording is possible, and the time required for recording is extremely short. Have.

[0006]

In order to enhance the transfer quality in the magnetic transfer as described above, it is important that the entire surface of the master carrier and the entire surface of the slave medium are maintained at a uniform distance from each other during the transfer. It is. Because it is actually difficult to maintain a uniform distance in a separated state,
Actually, magnetic transfer is performed in a state where the master carrier and the slave medium are in close contact as described above. Therefore, before the magnetic transfer, there is a case where the master carrier and the slave medium are positioned in close contact with each other, and the master carrier and the slave medium rub against each other at the time of this positioning. The carried pattern surface shape is worn and transfer accuracy is reduced.

When the transfer accuracy is reduced due to wear, the master carrier needs to be replaced. However, this master carrier is very expensive and can be transferred to any number of slave media with one master carrier. This is a very important issue in controlling manufacturing costs.

[0008] On the other hand, if a poor adhesion occurs at a part of the master carrier and the slave medium when the master medium and the slave medium are in close contact with each other, the uniformity of the positional relationship between the two cannot be maintained over the entire surface, and the transfer quality deteriorates. Become. In some cases, an area where magnetic transfer is not performed may occur at a poor adhesion position, a signal dropout occurs in the magnetic information transferred to the slave medium, the recording quality of the signal is reduced, and the recorded signal is a servo signal. In the case of (1), there is a problem that the tracking function cannot be sufficiently obtained and reliability is reduced.

In view of the above circumstances, it is an object of the present invention to provide a long-life magnetic transfer master carrier capable of performing magnetic transfer to more slave media.

Another object of the present invention is to provide a master carrier capable of performing good magnetic transfer without causing a signal drop in magnetic information transferred to a slave medium.

[0011]

A magnetic transfer master carrier according to the present invention is a magnetic transfer master carrier provided with a concavo-convex pattern for transferring information to a slave medium. It is characterized in that a rough surface is formed.

The rough surface may be formed on a part of the surface of the convex portion of the concavo-convex pattern, or may be formed on the entire surface. Also, not only the convex surface,
It may be formed on the concave surface.

The above-mentioned magnetic transfer master carrier specifically includes, for example, a substrate, and a soft magnetic layer provided on at least a portion of the substrate which will be the convex portion of the concavo-convex pattern. The rough surface may be formed according to a rough surface formed by a surface treatment applied to at least a portion of the substrate where the soft magnetic layer is provided. Here, the surface treatment performed on the substrate may be, for example, a texture treatment by polishing, a texture treatment by laser, or a treatment for corroding the surface.

Further, the master carrier for magnetic transfer of the present invention comprises a substrate, a granular material applied on at least a portion of the substrate which will be the convex portion of the concavo-convex pattern, and a magnetic carrier formed on the granular material. And a soft magnetic layer, wherein the rough surface is formed in accordance with the surface shape of the projection on which the granular material is applied.

Further, the magnetic transfer master carrier of the present invention comprises a substrate, and a soft magnetic layer provided on at least a portion of the substrate which will be the convex portion of the concavo-convex pattern. May be formed with surface roughness controlled by the conditions for forming the soft magnetic layer, for example, conditions such as sputtering.

Further, the magnetic transfer master carrier of the present invention comprises a substrate, a porous film provided on at least a portion of the substrate which becomes the convex portion of the concave / convex pattern, and a porous film formed on the porous material. A soft magnetic layer, wherein the rough surface is formed according to the surface shape of the porous film. In this case, the porous membrane has a volume ratio of 30.
% To 99%, and the surface roughness is Rp = 0.0001 to 0.1%.
It is desirably in the range of 1.

In each of the magnetic transfer master carriers, it is preferable that the rough surface is an uneven surface having a concave portion having a depth of 3 nm to 50 nm. More preferably 5
nm to 20 nm.

[0018]

The master carrier for magnetic transfer according to the present invention has a rough surface formed on the convex surface of the concave / convex pattern in contact with the slave medium, so that it can be compared with the conventional case where the entire convex surface is in contact with the slave medium. As a result, the actual contact area with the slave medium can be reduced, so that the friction coefficient at the time of contact between the two and especially at the time of positioning of both can be reduced, and as a result, the wear of the uneven pattern can be delayed. . Therefore, the life of the master carrier is extended, and magnetic transfer to more slave media becomes possible. As a result, the cost of magnetic transfer can be reduced, and a preformatted slave medium can be provided at a low price.

Further, if the transfer is made in close contact with the slave medium and the separation from the slave medium becomes difficult, it becomes necessary to apply extra force to the master carrier or the slave medium, which may cause damage. However, if the true contact area is small as in the present invention, it is easy to peel off, and there is also an effect of eliminating one cause of breakage.

Further, since the rough surface is formed, it is easy to bleed air when it comes into contact with the slave medium, so that the adhesion with the slave medium can be improved. By improving the adhesion, the occurrence of signal omission can be prevented and the recording quality of the transfer signal can be improved.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, the basic steps of magnetic transfer for transferring information to a slave medium using a master carrier will be described with reference to FIGS.

FIG. 1 is a perspective view showing a slave medium 2 and master carriers 1 and 1 '. The slave medium 2 is, for example, a flexible disk in which a hub 2b is fixed to the center of a disk-shaped recording medium 2a. It has recording surfaces 2d and 2e having magnetic layers formed on both surfaces.

The master carriers 1 and 1 ′ are formed on a toroidal disk by a rigid or flexible base, and a transfer pattern is formed on one surface of the master carrier 1, 1 ′. It has an information carrying surface. The master carrier 1, 1 ′ has an uneven pattern for the lower recording surface 2 d and the upper recording surface 2 e of the slave medium 2, respectively. The concavo-convex pattern is formed in a donut-shaped region surrounded by a dotted line in the figure, taking the master carrier 1 as an example. In addition, the master carrier of the present invention has a rough surface described later on at least the surface of the convex portion of the uneven pattern.

If the uppermost layer is coated with a protective film such as diamond-like carbon (DLC), the protective film improves the contact durability and enables a large number of magnetic transfers.
Further, a Si film may be formed below the DLC protective film by sputtering or the like.

FIGS. 2A and 2B are diagrams for explaining the basic steps of the magnetic transfer. FIG. 2A shows a step of applying a magnetic field in one direction to perform initial DC magnetization of the slave medium, and FIG. FIG. 7C is a diagram showing a step of applying a magnetic field in the opposite direction by bringing the carrier and the slave medium into close contact with each other, and FIG. In FIG. 2, only the lower recording surface 2d of the slave medium 2 is shown.

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). Thereafter, as shown in FIG. 2 (b), the recording surface 2d of the slave medium 2 is brought into close contact with the information carrying surface of the substrate 3 of the master carrier 1 in which the magnetic layer 6 is coated on the concave / convex pattern. In the track direction, the transfer magnetic field Hdu is opposite to the initial magnetic field Hin.
Is applied to perform magnetic transfer. As a result, as shown in FIG. 2C, information (for example, a servo signal) corresponding to the uneven pattern of the information carrying surface of the master carrier 1 is magnetically transferred and recorded on the magnetic recording surface (track) of the slave medium 2. Is done. Here, the lower recording surface 2d of the slave medium 2 and the lower master carrier 1 have been described. However, as shown in FIG. 1, the upper recording surface 2e of the slave medium 2 is also brought into close contact with the upper master carrier 1 '. Similarly, magnetic transfer is performed. The magnetic transfer to the upper and lower recording surfaces 2d and 2e of the slave medium 2 may be performed simultaneously, or may be performed one by one sequentially.

Further, even if the concave / convex pattern of the master carrier 1 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 transfer magnetic field Hdu
The same information can be magnetically transferred and recorded by reversing the direction described above. The initial magnetic field and the transfer magnetic field need to adopt values determined in consideration of the holding power of the slave medium and the relative magnetic permeability of the master carrier and the slave medium.

As the substrate of the master carrier, nickel,
Use silicon, quartz plate, glass, aluminum, alloy, ceramics, synthetic resin, etc. The formation of the concavo-convex pattern is performed by a stamper method, a photofabrication method, or the like. The depth of the concavo-convex pattern on the substrate (height of the protrusion) is preferably in the range of 80 nm to 800 nm, and more preferably in the range of 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 0.05 to 20 μm, and the length in the circumferential direction is preferably 0.05 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. .

As the magnetic material of the soft magnetic layer, Co, Co
Alloys (CoNi, CoNiZr, CoNbTaZr
Etc.), Fe, Fe alloys (FeCo, FeCoNi, Fe
NiMo, FeAlSi, FeAl, FeTaN), N
i, Ni alloy (NiFe) or the like is used. Particularly preferred are FeCo and FeCoNi. The soft magnetic layer is formed by depositing a magnetic material by vacuum deposition such as vacuum deposition, sputtering, or ion plating, or by plating. The thickness of the soft magnetic layer is 50 nm to 50 nm.
The range of 0 nm is preferred, and more preferably 150 nm.
４００400 nm.

Next, the master carrier according to the embodiment of the present invention will be described in detail. 3 to 7 show the first embodiment of the present invention.
It is a partial cross-sectional view of the master carrier according to the fifth to fifth embodiments. The substrate of the master carrier according to the first to fourth embodiments shown in FIGS. 3 to 6 is one in which a concavo-convex pattern is formed on the substrate surface, and this substrate is obtained by, for example, a stamper method or a fabrication method. Things.

The master carrier 11 according to the first embodiment shown in FIG.
Fine irregularities 15 formed by texturing by polishing or texturing by laser
And a soft magnetic layer 16 is formed thereon.
That is, fine irregularities 15 formed on the surface of the convex portion of the substrate 13
Accordingly, an uneven surface (rough surface) 17 is formed on the surface of the soft magnetic layer 16 provided thereon.

The master carrier 21 according to the second embodiment shown in FIG. 4, SiO ₂ on the substrate 23 surface having the uneven pattern
And the like, and a soft magnetic layer 26 is formed so as to cover the granular material 25. That is, an uneven surface (rough surface) 27 corresponding to the granular material 25 applied on the substrate 23 is formed on the surface of the soft magnetic layer 26.

The master carrier 31 according to the third embodiment shown in FIG. 5 has a soft magnetic layer 36 formed on the surface of a substrate 33 having an uneven pattern by sputtering or the like.
The surface roughness of the soft magnetic layer 36 is controlled by changing the conditions for forming the soft magnetic layer 36 by sputtering or the like, and the rough surface 37 is formed on the uneven pattern surface by this surface roughness.

The master carrier 41 according to the fourth embodiment shown in FIG. 6 comprises a porous film 44 on a substrate 43 having an uneven pattern.
Are formed, and a soft magnetic layer 46 is formed on the porous film 44. That is, a rough surface 47 corresponding to the surface shape 45 of the porous film 44 is formed on the surface of the soft magnetic layer 46 provided above the porous film 44. The volume ratio of the porous film 44 is 30% to 99%, and the surface roughness Rp is 0.0001.
It is desirably in the range of 0.1.

The porous film may be formed on the substrate with a material different from that of the substrate. For example, the porous film may be formed of nickel, silicon, quartz plate, glass, aluminum, alloy, ceramics, synthetic resin, or the like. Alternatively, the surface of the uneven pattern formed on the substrate may be formed into a porous film.
Examples of the method of forming the porous film include sintering and casting.However, in order to form finer irregularities, a method of electrically and chemically depositing on a mold, or a method of depositing a polymer solution or the like on the surface. A method of performing etching after coating is used.

The master carrier 51 according to the fifth embodiment shown in FIG. 7 is formed by forming a concavo-convex pattern by a soft magnetic layer 56 on a flat substrate 53. As described above, the concavo-convex pattern of the master carrier can be constituted by the soft magnetic layer 56. This master carrier 51 forms a rough surface 57 on the surface of the soft magnetic layer 56 by forming the soft magnetic layer 56 on the flat substrate 53 under appropriate film forming conditions in the same manner as in the third embodiment. Then, a concavo-convex pattern is formed by, for example, a photofabrication method. In addition, in order to form a rough surface, a texture process is performed on the substrate surface in the same manner as in the case of the master carrier according to the above-described first, second, or fourth embodiment. For example, a granular substance may be applied, or a porous film may be provided between the substrate and the soft magnetic layer.

In each of the above embodiments, when the rough surface formed on the surface of the uneven pattern has an uneven surface, the depth of the concave portion of the rough surface is preferably about 3 nm to 50 nm, more preferably. Is 5 nm to 20 nm.

In the master carrier according to each of the above embodiments, a protective film may be provided on the surface of the soft magnetic layer. Even when a protective film is provided on the soft magnetic layer, a rough surface is formed on the surface of the protective film, which is the uppermost layer, according to the rough surface of the soft magnetic layer surface as described above. A master carrier having a rough surface at least on the surface of the convex portion can be obtained.

When the above-described magnetic transfer is performed using each of the master carriers according to the embodiment of the present invention as described above, the true contact area at the time of positioning with the slave medium due to the rough surface on the convex surface of the concave / convex pattern. Is smaller than before, the friction coefficient between the two is small, the abrasion of the uneven pattern can be delayed, air can easily escape during close contact, good adhesion can be obtained, and both can be easily separated after magnetic transfer. Can be. Therefore, the life of the master carrier can be extended, and good magnetic transfer can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a slave medium and a master carrier.

FIG. 2 is a diagram showing basic steps of a magnetic transfer method.

FIG. 3 is a partial cross-sectional view of the master carrier according to the first embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a master carrier according to a second embodiment of the present invention.

FIG. 5 is a partial sectional view of a master carrier according to a third embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a master carrier according to a fourth embodiment of the present invention.

FIG. 7 is a partial sectional view of a master carrier according to a fifth embodiment of the present invention.

[Explanation of symbols]

 1, 11, 21, 31, 41, 51 Master carrier 2 Slave medium 3, 13, 23, 33, 43, 53 Substrate 6, 16, 26, 36, 46, 56 Soft magnetic layer 15 Fine irregularities 17, 27, 37, 47, 57 Rough surface 25 Granular material 44 Porous membrane

Claims (7)

[Claims] 1. A magnetic transfer master carrier provided with a concavo-convex pattern for transferring information to a slave medium, wherein a rough surface is formed on a surface of a convex portion of the concavo-convex pattern. For master carrier. 2. A semiconductor device comprising: a substrate; and a soft magnetic layer provided on at least a portion of the substrate that becomes a convex portion of the concavo-convex pattern, wherein the rough surface has at least the soft magnetic layer of the substrate. 2. The method according to claim 1, wherein the surface is formed in accordance with a rough surface formed by a surface treatment applied to a location where the surface is provided.
A master carrier for magnetic transfer as described in the above. 3. A substrate, and a granular material applied on at least a portion of the substrate that becomes a convex portion of the concavo-convex pattern,
A soft magnetic layer formed on the granular material, wherein the rough surface is formed in accordance with a surface shape of the convex portion on which the granular material is applied. Item 7. A master carrier for magnetic transfer according to Item 1. 4. A substrate comprising: a substrate; and a soft magnetic layer provided on at least a portion of the substrate which becomes a convex portion of the concavo-convex pattern, wherein the rough surface is controlled by forming conditions of the soft magnetic layer. 2. The master carrier for magnetic transfer according to claim 1, wherein the master carrier is formed by a surface roughness to be obtained. 5. A substrate, and a porous film provided on at least a portion of the substrate that becomes a convex portion of the concavo-convex pattern;
The magnetic transfer according to claim 1, further comprising a soft magnetic layer formed on the porous material, wherein the rough surface is formed according to a surface shape of the porous film. For master carrier. 6. The porous membrane having a volume ratio of 30% to 9%.
The master carrier for magnetic transfer according to claim 5, wherein 9% and the surface roughness are in the range of Rp = 0.0001 to 0.1. 7. The master carrier for magnetic transfer according to claim 1, wherein the rough surface is an uneven surface having a concave portion having a depth of 3 nm to 50 nm.