JP4662594B2 - Method for removing foreign matter from master magnetic information carrier - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a master magnetic information carrier such as a master disk used for the purpose of performing preformat recording such as a servo signal, an address signal or a reproduction clock signal on a magnetic recording medium, and in particular, on the surface of the master magnetic information carrier. The present invention relates to a method for removing existing foreign matter.
[0002]
[Prior art]
As the recording density of magnetic recording media is increased and the time required for preformatting is increased, preformat information is collected by magnetic transfer technology using a master disk instead of servo signal line writing by a servowriter. Thus, a preformat recording method for surface writing has been proposed for several years, and the servo signal recording time has been greatly shortened.
[0003]
The master magnetic information carrier is manufactured by, for example, applying a resist on the surface of a silicon substrate by spin coating or the like, then patterning by a photolithography method, and performing reactive plasma etching through an etching mask formed thereby. A method is generally used in which a digging hole is formed in a silicon substrate, a cobalt-based soft magnetic film is sputtered into the hole, and then the etching mask and the soft magnetic film thereon are removed with a resist solvent. .
[0004]
In such a method of manufacturing a master magnetic information carrier, the resist is removed by a lift-off method, but if the resist pattern undercut is not sufficiently formed, the magnetic film covers the side wall of the resist layer, Since it cannot be removed by the solvent, so-called burrs 13 of the cobalt-based soft magnetic film 12 formed on the silicon substrate 11 are generated as shown in FIG.
[0005]
When the magnetic transfer operation is carried out by bringing the master magnetic information carrier having such burrs 13 into contact with the surface of the magnetic disk medium, the burrs 13 are broken and transferred to the magnetic disk at the time of contact. When such a foreign substance exists on the magnetic disk, it collides with a magnetic head for reading / writing information and causes noise, and in the worst case, a head crash occurs.
[0006]
Further, in order to improve the durability of the master magnetic information carrier and extend its life, a DLC (diamond-like carbon) film or the like is usually formed on the surface by a sputtering method. If there is, there is a problem that the DLC film peels off from that portion.
[0007]
Various attempts have been made to remove burrs by brushing or polishing.Brushing cannot completely remove burrs, but polishing removes burrs that have entered the gap between silicon and cobalt particles. When the work is repeated, there is a problem that this moves and adheres to the magnetic disk (hereinafter referred to as “transfer”).
[0008]
Therefore, it was unavoidable that the first dozens of transfer operations were used as dummy magnetic disks, and the burr was transferred to the dummy disk before performing the actual transfer operation. However, this method has the following problems. was there.
(B) The first several dozen dummy disks will be discarded, which increases the cost. (B) Since the surface of the magnetic disk has a DLC protective film formed thereon and is hard, the master magnetic information carrier may be damaged.
(C) Since the lubricant is applied to the surface of the magnetic disk, it is transferred to the master magnetic information carrier, and the contact distance between the master magnetic information carrier and the magnetic disk changes.
[0009]
[Problems to be solved by the invention]
In order to eliminate the transfer of foreign matter from the master magnetic information carrier as described above to the magnetic disk, which occurs at the time of magnetic transfer, the present invention removes foreign matter present on the surface of the master magnetic information carrier in advance before performing magnetic transfer. In view of the above-mentioned experience, it is hard enough to break the burrs of the master magnetic information carrier, but does not scratch the surface of the master magnetic information carrier and provides master magnetic information. It is an object of the present invention to provide a foreign substance transfer substrate that has sufficient flatness to be in close contact with the surface of the carrier and is sufficiently profitable in terms of cost.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a master magnetic information carrier comprising a buried magnetic layer surrounded by a surface portion of a substrate and having a surface flush with the surface of the surface portion. The surface of the information carrier is NiP plated (except for those having magnetic properties such as Co—Re—P, Co—Ni—P, and Co—Ni—Re—P). This is achieved by bringing the foreign matter present on the surface of the master magnetic information carrier onto the surface of the NiP-plated aluminum substrate by bringing it into close contact with the surface of the aluminum substrate.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
According to the first embodiment of the present invention, the surface of the master magnetic information carrier is brought into close contact with the surface of the NiP-plated and polished aluminum substrate several times instead of once (claim 2).
[0012]
According to the second embodiment of the present invention, the surface of the master magnetic information carrier is brought into close contact with the surface of a single NiP-plated and polished aluminum substrate, and this operation is performed on a plurality of aluminum substrates. (Claim 3).
[0013]
According to the third embodiment of the present invention, the diameter of the NiP plated and polished aluminum substrate is made larger than the diameter of the master magnetic information carrier.
[0014]
According to the fourth embodiment of the present invention, the diameter of the NiP-plated and polished aluminum substrate is made smaller than the diameter of the master magnetic information carrier, and one aluminum substrate and the master magnetic information carrier are bonded to each other. The contact with the entire area of the master magnetic information carrier is performed by making contact a plurality of times while changing the relative position, and this operation is repeated for a plurality of aluminum substrates.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first embodiment of the present invention. A master magnetic information carrier 2 having a burr 1 on its surface is adsorbed to an upper moving body 3 by a vacuum adsorption mechanism (not shown). Here, the foreign matter of the master magnetic information carrier 2 is the burr 1, but it may be a foreign matter such as a particle, metal, or organic matter attached from the outside, commonly called contamination.
[0016]
4 is an aluminum substrate, the surface of which is NiP plated (electroless nickel-phosphorus alloy plated) and then polished (mirror finish), and is adsorbed to the lower fixed body 5 by a vacuum suction mechanism (not shown).
[0017]
The master magnetic information carrier 2 and the aluminum substrate 4 are initially separated by a certain distance as shown in FIG. The upper movable body 3 is lowered to bring the master magnetic information carrier 2 and the aluminum substrate 4 into contact with each other as shown in FIG. 1B, and at the same time, a vacuum is formed through the hole 6 formed at the center of the lower fixed body 5. When pulling, the master magnetic information carrier 2 and the aluminum substrate 4 are firmly attached. After that, when the pressure in the hole 6 is returned to the atmospheric state and the upper movable body 3 is raised as shown in FIG. 1C), a part (fragment) of the burr 1 generally becomes the surface of the aluminum substrate 4. Move to.
[0018]
Whether or not to replace the aluminum substrate after completing the series of operations A) to C) in FIG. 1 depends on the situation, but any of the following methods can be adopted depending on the result of the experiment.
1) After the series of operations A) to C) is completed, the aluminum substrate is replaced.
2) A series of operations A) to C) are repeated a plurality of times without replacing the aluminum substrate.
3) First, the series of operations A) to C) is repeated a plurality of times without replacing the aluminum substrate, and then the aluminum substrate is replaced every time the series of operations A) to C) is completed.
4) First, the aluminum substrate is replaced every time the series of operations A) to C) is completed, and then the sequence of operations A) to C) is repeated a plurality of times without replacing the aluminum substrate.
[0019]
FIG. 2 shows a second embodiment of the present invention, and the same parts as those in FIG. In this embodiment, the diameter of the aluminum substrate 4 is selected larger than the diameter of the master magnetic information carrier 2. Thereby, the burr | flash 1 which exists near the outer periphery of the master magnetic information carrier 1 can be removed reliably.
[0020]
FIG. 3 shows a third embodiment of the present invention. The same reference numerals are given to the same parts as those in FIG. In this embodiment, the diameter of the aluminum substrate 4 is selected to be smaller than the diameter of the master magnetic information carrier 2. For this reason, the burr 10 existing near the outer periphery of the master magnetic information carrier 2 cannot be reliably removed only by performing the operations of A) to C) in FIG. 3 once.
[0021]
Therefore, in this case, when the operations of A) to C) in FIG. 3 are repeated a plurality of times, the contact area between the master magnetic information carrier 2 and the aluminum substrate 4 is changed, so that the aluminum substrate 4 carries the master magnetic information carrier. Cover the entire area of the body 2.
[0022]
This will be described in detail with reference to FIG. FIG. 4 is a perspective view of the relative relationship between the master magnetic information carrier 2 and the aluminum substrate 4 in FIG. 3 as seen from above. If the aluminum substrate 4 and the master magnetic information carrier 2 are concentric as shown in FIG. 3, burrs existing near the outer periphery of the master magnetic information carrier 2 cannot be reliably removed.
[0023]
Therefore, in the first operation, as shown in FIG. 4A), the center of the master magnetic information carrier 2 is shifted from the center of the aluminum substrate 4 to the position indicated by 21 in the upper right, and the series of operations in FIG. . In the second operation, as shown in FIG. 4B, the center of the master magnetic information carrier 2 is shifted from the center of the aluminum substrate 4 to the position indicated by 22 in the upper left, and the series of operations in FIG. In the third operation, as shown in FIG. 5C, the center of the master magnetic information carrier 2 is shifted from the center of the aluminum substrate 4 to the position indicated by the lower left 23, and the series of operations in FIG. In the fourth operation, as shown in FIG. 4D), the center of the master magnetic information carrier 2 is shifted from the center of the aluminum substrate 4 to the position indicated by the lower right 24, and the series of operations in FIG.
[0024]
With the above operation, the entire area of the master magnetic information carrier 2 can be covered.
[0025]
FIG. 6 is an experimental result when the operation of FIG. 3 which is the second embodiment of the present invention is repeated by replacing the aluminum substrate every time. The horizontal axis represents the number of close contacts of the master magnetic information carrier, and the vertical axis represents the number of foreign matters transferred to the aluminum substrate each time. As can be seen from this figure, a large amount of foreign matter such as burrs on the surface of the master magnetic information carrier is transferred to the aluminum substrate at first, but the number of transferred particles decreases as the number of times is repeated, and 50 times It becomes several levels. That is, if the preformat recording operation is performed in which the preformat information is collectively written by magnetic transfer after the operation of FIG. 3 is repeated 50 times, there is almost no foreign matter transferred to the actual recording medium.
[0026]
【The invention's effect】
As described above, according to the present invention, NiP plating (provided that Co—Re—P, Co—Ni—P, Co—Ni—Re) is used to remove foreign matter adhering to the surface of the master magnetic information carrier. Using an aluminum substrate having a polished finish , except for those having magnetic characteristics such as -P, has the effect of removing almost all foreign substances without damaging the surface of the master magnetic information carrier.
[Brief description of the drawings]
FIGS. 1A to 1C are schematic cross-sectional views showing working steps of a first embodiment of the present invention.
FIGS. 2A to 2C are schematic cross-sectional views showing work steps of a second embodiment of the present invention. FIGS.
FIGS. 3A to 3C are schematic cross-sectional views showing working steps of a third embodiment of the present invention. FIGS.
FIGS. 4A to 4D are schematic plan views showing a work process according to a third embodiment of the present invention in plan view.
FIG. 5 is a cross-sectional view of burrs generated in a master magnetic information carrier.
FIG. 6 is a bar graph showing the transition of the number of master contacts and the number of remaining foreign matters.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,10 ... Foreign matter 2,21,22,23,24 ... Master magnetic information carrier 3 ... Upper moving body 4 ... Aluminum substrate 5 ... Lower fixed body 6 ...・ Hole

Claims (5)

In a master magnetic information carrier having a buried magnetic layer surrounded by the surface of the substrate and having a surface flush with the surface of the surface, the surface of the master magnetic information carrier is NiP-plated (however, Co-Re -P, Co-Ni-P, Co-Ni-Re-P, etc., which have magnetic properties are excluded.) The surface of the master magnetic information carrier is adhered to the surface of the polished aluminum substrate . A foreign matter removing method for a master magnetic information carrier comprising transferring foreign matter present in the surface of a NiP-plated aluminum substrate. In a master magnetic information carrier having a buried magnetic layer surrounded by the surface of the substrate and having a surface flush with the surface of the surface, the surface of the master magnetic information carrier is NiP-plated (however, Co-Re -P, Co-Ni-P, Co-Ni-Re-P, etc., which have magnetic properties are excluded.) The master magnetic information carrier is adhered to the surface of the polished aluminum substrate a plurality of times. A foreign matter removing method for a master magnetic information carrier comprising transferring foreign matter existing on the surface of a NiP-plated aluminum substrate. In a master magnetic information carrier comprising a buried magnetic layer surrounded by a surface portion of a substrate and having a surface flush with the surface of the surface portion, the surface of the master magnetic information carrier is coated with a single NiP plate (however, Except for those having magnetic properties such as Co-Re-P, Co-Ni-P, and Co-Ni-Re-P.) A foreign matter removing method for a master magnetic information carrier, wherein the foreign matter existing on the surface of the master magnetic information carrier is transferred to the surface of the NiP-plated aluminum substrate by repeating with respect to a single aluminum substrate. 4. The foreign matter removal method for a master magnetic information carrier according to claim 1, wherein the diameter of the NiP-plated and polished aluminum substrate is larger than the diameter of the master magnetic information carrier. A method for removing foreign matter from a master magnetic information carrier. In the foreign matter removal method of the master magnetic information carrier according to any one of claims 1 to 3, the diameter of the NiP-plated and polished aluminum substrate is made smaller than the diameter of the master magnetic information carrier, By making contact with the entire area of the master magnetic information carrier by making multiple contact while changing the relative position of the aluminum substrate and the master magnetic information carrier, by repeating this operation for a plurality of aluminum substrates A foreign matter removing method for a master magnetic information carrier, wherein foreign matter present on the surface of the master magnetic information carrier is transferred to the surface of an aluminum substrate plated with NiP.

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