JP2004139628A - Master carrier for magnetic transfer, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a noise component involved by magnetic transfer and to enhance transfer characteristics, in a master carrier having a rugged pattern of a magnetic layer and used in a magnetic transfer method by which magnetic transfer of an information signal such as a servo signal is performed to a slave medium. <P>SOLUTION: The rear surface 2b of the magnetic layer 2 whose surface 2a has the rugged pattern corresponding to transfer information is flatly provided by polishing and a flat substrate 3 is layered on the flat rear surface 2b. The flat substrate 3 is layered by electroforming of Ni. A resin liquid is applied onto a master disk on which a rugged pattern corresponding to the information is formed and the resin liquid is cured to form a resin substrate. The magnetic layer 2 is formed by film-depositing the magnetic layer 2 on the rugged pattern of the resin substrate. Ruggedness of the rear surface 2b of the magnetic layer 2 is polished and flattened, the flat substrate 3 is layered on the flattened rear surface 2b by electroforming and the resin substrate is stripped from the rugged pattern of the magnetic layer 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic transfer master carrier used in a magnetic transfer method for magnetic transfer from a master carrier carrying transfer information to a slave medium that receives the transfer, and a method for manufacturing the same.
[0002]
[Prior art]
In the magnetic transfer of the present invention, a master carrier (patterned master) on which a transfer pattern such as a servo signal having a magnetic layer on at least a surface layer is formed in a concavo-convex shape is brought into close contact with a slave medium having a magnetic recording portion. In this state, a magnetic field for transfer is applied to transfer and record the magnetization pattern corresponding to the information carried on the master carrier onto the slave medium.
[0003]
As an example of the master carrier used for the magnetic transfer, a substrate formed by forming a concavo-convex pattern corresponding to an information signal on the surface of a substrate and coating a thin film magnetic layer on the surface of the concavo-convex pattern has been proposed ( For example, see Patent Document 1).
[0004]
The concavo-convex pattern of this master carrier is drawn by irradiating a laser or electron beam modulated according to information while rotating a disk coated with a photoresist, and plating the original plate with concavo-convex developed by this photoresist. The metal plate formed by peeling off after taking the metal mold is used as a master and the uneven shape is copied on the surface of the substrate.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-256644 [0006]
[Problems to be solved by the invention]
By the way, in the magnetic transfer master carrier as described above, a substrate having a concavo-convex pattern corresponding to the transfer information on the surface is first prepared with a concavo-convex pattern formed by a magnetic layer required for magnetic transfer. Since the magnetic layer is obtained by coating the magnetic layer in a concavo-convex shape, this magnetic layer is provided on the bottom surface of the concave portion with the same film thickness as the top surface of the convex portion. When transfer is performed, the transferred magnetization pattern easily includes noise, and further improvement is desired in terms of transfer signal quality.
[0007]
As a result of analyzing the above points, the noise component in the magnetization pattern transferred to the slave medium is caused by the magnetic layer formed on the bottom surface of the concave portion of the concave and convex pattern of the master carrier. It was found that the smaller the thickness of the magnetic layer on the bottom surface, the less noise is contained.
[0008]
In the case where the magnetic layer is coated on the concave / convex pattern of the substrate, the concave / convex shape on the surface of the magnetic layer does not accurately represent the concave / convex shape of the substrate on the bottom surface of the magnetic layer, and the width of the convex portion becomes wider. Or a curved surface is formed at the corner of the convex portion, which becomes more noticeable as the magnetic layer becomes thicker, and there is a problem that affects the quality of the transfer signal, the positional accuracy, and the like.
[0009]
The present invention has been made in view of the above points, and an object of the present invention is to provide a master carrier for magnetic transfer that has few transfer noise components and excellent transfer characteristics, and a method for manufacturing the same.
[0010]
[Means for Solving the Problems]
The magnetic transfer master carrier of the present invention is a master carrier used in a magnetic transfer method in which a master carrier carrying information and a slave medium to be transferred are brought into close contact with each other and applied with a magnetic field for transfer, and magnetic transfer is performed.
A magnetic layer having a concavo-convex pattern corresponding to transfer information on the front surface and having a back surface flattened by polishing, and a flat substrate laminated on the flat back surface of the magnetic layer. .
[0011]
The flat substrate is preferably one in which Ni is laminated on the back surface of the magnetic layer by electroforming.
[0012]
The method for producing a magnetic transfer master carrier according to the present invention also includes a step of applying a resin liquid to a master on which a concavo-convex pattern according to information is formed, and curing the resin base to produce a resin base. After forming a magnetic layer and polishing and flattening the unevenness of the back surface of the magnetic layer, a flat substrate is laminated on the flat back surface by electroforming, and the resin substrate is peeled off from the uneven pattern of the magnetic layer, A master carrier provided with a magnetic layer and a flat substrate is produced.
[0013]
The master is preferably a metal master obtained by electroforming a concavo-convex pattern formed by drawing exposure on a photoresist, removing a metal mold, and then peeling.
[0014]
The resin substrate is preferably produced by curing a light curable resin such as an ultraviolet curable resin. The magnetic layer is preferably formed by sputtering or electroforming.
[0015]
For the backside polishing of the magnetic layer, it is preferable to use a method that does not give strain to the magnetic layer, such as flat polishing or lapping.
[0016]
【The invention's effect】
According to the master carrier of the present invention as described above, the back surface of the magnetic layer having a concavo-convex pattern corresponding to the transfer information is flattened by polishing, and a flat substrate is laminated on the flat back surface of the magnetic layer. The thickness of the magnetic layer on the bottom surface of the concave portion of the transfer pattern is smaller than the thickness of the magnetic layer on the convex portion, so that magnetic transfer with less noise can be performed, and reliability can be ensured by improving the transfer quality.
[0017]
In addition, according to the manufacturing method of the present invention, the formation accuracy of the concave / convex pattern on the surface of the magnetic layer is increased and the thickness of the magnetic layer on the bottom surface of the concave portion is reduced.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a cross-sectional view of a master carrier for magnetic transfer according to one embodiment of the present invention, and FIG. 2 is a diagram sequentially illustrating steps for producing a master carrier according to one embodiment. Each figure is a schematic diagram, and is shown in a ratio different from the actual dimensions.
[0019]
A magnetic transfer master carrier 1 shown in FIG. 1 includes a magnetic layer 2 and a substrate 3. The magnetic layer 2 has an uneven pattern (transfer pattern) corresponding to transfer information on the front surface 2a, and the back surface 2b has a back surface 2b. Flattened by polishing. The substrate 3 is formed by laminating Ni, for example, on the flat back surface 2b of the magnetic layer 2 by electroforming.
[0020]
The height of the protrusions in the concavo-convex pattern of the magnetic layer 2 is preferably in the range of 80 to 800 nm, more preferably in the range of 100 to 600 nm.
[0021]
At the time of magnetic transfer, the surface 2a (uneven pattern) of the magnetic layer 2 in the master carrier 1 and the slave medium 4 that receives the transfer indicated by the chain line are brought into close contact, and a magnetic field for transfer is applied to perform magnetic transfer. At this time, the slave medium 4 is preliminarily magnetized in one of the in-plane direction and the vertical direction, and the transfer magnetic field is applied in the in-plane direction or the vertical direction substantially opposite to the initial magnetization.
[0022]
Then, the magnetic field for transfer applied during the magnetic transfer is sucked into the convex portion of the magnetic layer 2 in close contact with the slave medium 4 in the concave / convex pattern of the master carrier 1, and in the case of in-plane recording, the initial magnetization of this portion is In the case of perpendicular recording, the initial magnetization of this portion is reversed and the initial magnetization of the other portion is not reversed. As a result, the master carrier 1 is provided in the magnetic recording layer of the slave medium 4. A magnetized pattern corresponding to the uneven pattern is transferred and recorded.
[0023]
Note that the master carrier 1 has an initial magnetic field direction and a transfer magnetic field with respect to the slave medium 4 even when the concave-convex pattern of the magnetic layer 2 is a negative concave pattern opposite to the positive pattern of FIG. A similar magnetization pattern can be transferred and recorded by changing the application direction of.
[0024]
In the magnetic transfer using the master carrier 1 as described above, since the thickness of the concave portion in the concave / convex pattern of the magnetic layer 2 is thin, the noise component at the time of magnetic transfer to the slave medium 4 is reduced, and the transfer has high signal quality. Can record.
[0025]
As will be described in detail later, the master carrier 1 is prepared by applying a resin liquid to a master on which a concavo-convex pattern corresponding to information is formed and curing the resin base. A magnetic layer is formed on the concavo-convex pattern of the resin base. 2 is formed, the unevenness of the back surface 2b of the magnetic layer 2 is polished and flattened, and then a flat substrate 3 is laminated on the flat back surface 2b of the magnetic layer 2 by electroforming, and then peeled off from the resin substrate. Made.
[0026]
A method for producing an embodiment of the master carrier 1 will be described with reference to FIGS.
[0027]
When the magnetic layer 2 is formed in the steps (a) to (d), the resin substrate 14 for forming a fine uneven pattern on the surface 2a is prepared. First, a photoresist film 11 is formed by applying a photoresist solution by spin coating or the like on an original plate 10 (which may be a glass plate or a quartz plate) made of a silicon wafer having a smooth surface as shown in FIG. . Then, with an electron beam exposure apparatus (not shown) equipped with a high-precision rotary stage, the electron beam EB modulated in accordance with the servo signal is irradiated while rotating the original plate 10 mounted on the rotary stage. A desired pattern is drawn and exposed on the photoresist film 11. Thereafter, as shown in (b), the photoresist film 11 is developed, the exposed portion is removed, and a desired uneven pattern (negative pattern) is formed with a desired thickness by the remaining photoresist film 11. An Ni conductive film 12 is applied on the uneven pattern to enable electroforming.
[0028]
Next, as shown in (c), an electroforming process is performed on the concavo-convex pattern on the surface of the original plate 10 by an electroforming apparatus to produce a master 13 made of Ni metal having a desired thickness. The metal master 13 having the uneven pattern (positive pattern) is peeled off from the master 10 and the remaining photoresist film 11 is removed and washed.
[0029]
Next, as shown in (d), a concavo-convex pattern in which a photo-curing resin such as an ultraviolet curable resin is applied on the metal master 13 and cured by irradiating with special light such as an ultraviolet ray, and inverted into a negative shape. The resin substrate 14 having the above is manufactured and peeled off from the metal master 13.
[0030]
Next, as shown in (e), the resin layer 14 is used to form the magnetic layer 2 on the concavo-convex pattern to a predetermined thickness by sputtering, electroforming, or the like. In the state after the film formation, the surface of the magnetic layer 2 is reversely formed with a positive concavo-convex pattern by the negative concavo-convex pattern of the resin substrate 14, and the opposite back surface of the magnetic layer 2 has a concavo-convex shape reflecting the concavo-convex pattern. It has become.
[0031]
Then, as shown in (f), the uneven surface on the back surface side of the magnetic layer 2 as it is formed on the resin substrate 14 is polished, and the convex portion is removed to form a flat back surface 2b. The polishing of the magnetic layer 2 is performed using a polishing method such as flat polishing or lapping that does not cause distortion of the magnetic layer 2.
[0032]
Next, as shown in (g), an electroforming process is performed on the flat back surface 2b obtained by polishing the magnetic layer 2 with Ni having a desired thickness, and the Ni flat substrate 3 is laminated. After that, the magnetic layer 2 is peeled off from the concave / convex pattern of the resin substrate 14 together with the flat substrate 3 and has a concave / convex pattern on the front surface 2a of the magnetic layer 2 and flat on the flat back surface 2b of the magnetic layer 2 as shown in (h). The master carrier 1 formed by laminating the substrate 3 is produced.
[0033]
In the production of the original plate 10, after the photoresist film 11 is exposed and developed, an etching process is performed to form an uneven pattern by etching on the surface of the wafer original plate 10, and then the photoresist film 11 is removed. Also good. After the Ni conductive film 12 is applied on the concavo-convex pattern, the metal master 13 having the positive concavo-convex pattern can be produced by performing an electroforming process as in FIG. In addition, a plurality of resin substrates 14 can be manufactured by repeatedly using the metal master 13.
[0034]
At the time of producing the resin base 14, an ultraviolet curable resin liquid is applied to the metal master 13, and then a plate member made of an ultraviolet transmitting material is pressed to a uniform thickness, and ultraviolet rays are irradiated through the plate member to cure the resin liquid ( The resin substrate 14 may be produced by photopolymerization. The said plate member is good also as a part of resin base | substrate as it is after shaping | molding.
[0035]
In FIG. 2, the back surface of the metal master 13 formed by the electroforming process is shown flat, but there is no problem in forming the resin substrate 14 even if an uneven shape is formed on the back surface.
[0036]
The magnetic layer 2 is formed by depositing a magnetic material by a vacuum film forming means such as a vacuum deposition method, a sputtering method, or an ion plating method, or a plating method such as electroforming. As the magnetic material of the magnetic layer 2, Co, Co alloy (CoNi, CoNiZr, CoNbTaZr, etc.), Fe, Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi, FeAl, FeTaN), Ni, Ni alloy (NiFe) should be used. Can do. Particularly preferred are FeCo and FeCoNi.
[0037]
A protective film such as diamond-like carbon (DLC) is preferably provided on the surface 2a (uneven pattern) of the magnetic layer 2, and a lubricant layer may be provided. More preferably, a 5-30 nm DLC film and a lubricant layer are present as the protective film. The lubricant improves the deterioration of durability such as the occurrence of scratches due to friction when correcting the deviation caused in the contact process with the slave medium 4.
[0038]
As the slave medium 4, a hard disk, a high-density flexible disk, or the like is used, and the magnetic recording layer is formed with a coating type magnetic recording layer or a metal thin film type magnetic recording layer. For the metal thin film type magnetic recording layer, Co, Co alloy (CoPtCr, CoCr, CoPtCrTa, CoPtCrNbTa, CoCrB, CoNi, etc.), Fe, Fe alloy (FeCo, FePt, FeCoNi) can be used as the magnetic material.
[0039]
In the master carrier 1 manufactured by the above-described production method, the concave / convex pattern on the surface 2a of the magnetic layer 2 becomes a pattern in which the concave / convex pattern of the resin substrate 14 is directly shaped and inverted, so that the convex portion width, the convex portion It is possible to form a highly accurate pattern such as a cross-sectional shape.
[0040]
Further, the workability is excellent by polishing and laminating the substrate 3 while the magnetic layer 2 is formed on the resin substrate 14.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a master carrier for magnetic transfer according to one embodiment of the present invention. FIG. 2 is a diagram sequentially illustrating a manufacturing process of a master carrier according to one embodiment.
1 Master Carrier 2 Magnetic Layer 2a Surface (Unevenness Pattern)
2b Back surface 3 Flat substrate 10 Master plate 11 Photoresist film 12 Ni conductive film 13 Metal master 14 Resin base

Claims (7)

A master carrier used in a magnetic transfer method in which a master carrier carrying information and a slave medium to be transferred are brought into close contact with each other and a magnetic field for transfer is applied for magnetic transfer,
For magnetic transfer, comprising: a magnetic layer having a concavo-convex pattern according to transfer information on the front surface, and a back surface flattened by polishing; and a flat substrate laminated on the flat back surface of the magnetic layer. Master carrier. 2. The magnetic transfer master carrier according to claim 1, wherein the flat substrate is formed by stacking Ni on the magnetic layer by electroforming. A resin base is formed by applying a resin liquid to a master having a concavo-convex pattern according to information and curing it. A magnetic layer is formed on the concavo-convex pattern of the resin base. After polishing and flattening, a flat substrate is laminated on the flat back surface by electroforming, and the resin substrate is peeled off from the uneven pattern of the magnetic layer to produce a master carrier comprising the magnetic layer and the flat substrate. A method for producing a master carrier for magnetic transfer. 4. The magnetic transfer according to claim 3, wherein the master is a metal master obtained by electroforming a concavo-convex pattern formed by drawing exposure on a photoresist, removing a metal mold, and then peeling. For producing a master carrier for use in an automobile. 4. The method for manufacturing a magnetic transfer master carrier according to claim 3, wherein the resin substrate is made by curing a photo-curing resin such as an ultraviolet curable resin. 4. The method for producing a magnetic transfer master carrier according to claim 3, wherein the magnetic layer is formed by sputtering. 4. The method for producing a magnetic transfer master carrier according to claim 3, wherein the magnetic layer is formed by electroforming.

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