JPH0581662A - Production of perpendicular magnetic recording medium - Google Patents

Abstract

PURPOSE:To efficiently obtain many sheets of the perpendicular magnetic recording medium which are small in size and have uniform magnetic characteristics by decreasing the handling and improving the efficiency of the film forming stage thereof at the time of forming soft magnetic films of a 1st layer on a non-magnetic substrate by an electroplating method relating to the process for production of the perpendicular magnetic recording medium having two- layered films to be used for a magnetic disk device. CONSTITUTION:After the soft magnetic films 32 are formed on the surface of a nonmagnetic substrate 31 having the area of plural times the size of the recording medium to be formed, the nonmagnetic substrate 31 is cut and separated to a medium unit of a prescribed disk shape to form plural sheets of medium substrates 33. A stage for depositing and forming the perpendicular recording films on the soft magnetic films 32 of the respective medium substrates 33 separated in this stage is executed to form plural sheets of the perpendicular magnetic recording medium each having a two-layered film structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a perpendicular magnetic recording medium used in a magnetic disk device or the like, and more particularly to a method for efficiently forming a small perpendicular magnetic recording medium.

In recent years, due to an increase in the amount of information processing in a computer system, information recording on a magnetic disk device used as an external storage device has also increased, and miniaturization and large capacity have been promoted, resulting in high density recording. Is required.

Therefore, a perpendicular magnetic recording medium having a double-layer film structure has been proposed and put into practical use as a perpendicular magnetic recording medium capable of recording at a much higher density than the conventional horizontal magnetic recording medium. Is being done.

In such a perpendicular magnetic recording medium, there has been a demand for higher efficiency in the manufacturing process thereof along with improvement in recording / reproducing characteristics and miniaturization.

[0005]

2. Description of the Related Art A conventional perpendicular magnetic recording medium has an electrolytic plating method or a sputtering method on a non-magnetic substrate 12 made of an aluminum disk having a NiP plated surface, as shown in the schematic diagram of FIG. And the like, for example, a high magnetic permeability soft magnetic film 13 made of a Ni-Fe alloy film having a thickness of 1 μm,
It has a two-layer film structure in which a perpendicular recording film 14 made of Co—Cr or the like having a film thickness of 0.15 μm is laminated.

In the perpendicular magnetic recording medium 11 having such a double-layered film structure, as shown in the drawing, a region in which the non-magnetic insulating material 23 is embedded on the airflow outflow end surface of the ferrite slider, which partly serves as the magnetic flux return yoke 22. It is well known that the combination of the coil 24 and the main magnetic pole 25, which are covered with an interlayer insulating film, with the single magnetic pole type magnetic head 21 formed in a laminated shape is suitable for high-density recording / reproducing of information. Is.

[0007]

By the way, in recent years, there has been a strong demand for a magnetic disk device having a large capacity and a small size, and accordingly, the perpendicular magnetic recording medium used in the device has been downsized. ..

In such a situation, when mass-producing a perpendicular magnetic recording medium having a small double-layer film structure, for example, the high magnetic permeability soft magnetic film is electroplated on a large number of the non-magnetic substrates. When performing film formation by plating, perform plating pretreatment of each non-magnetic substrate, and perform electrical connection to each non-magnetic substrate after pre-treatment to one electrode of the plating power source to conduct electricity one by one. It is necessary to manually hang it in the liquid or remove the electrical connection of each non-magnetic substrate after plating, which is troublesome and troublesome. There was a troublesome problem.

In view of the above-mentioned conventional problems, the present invention significantly reduces the handling at the time of forming a high-permeability soft magnetic film on a non-magnetic substrate by electrolytic plating, and the film forming process It is an object of the present invention to provide a novel method for manufacturing a perpendicular magnetic recording medium, which is intended to improve efficiency and efficiently obtain a large number of small perpendicular magnetic recording media having uniform magnetic characteristics.

[0010]

In order to achieve the above-mentioned object, the present invention forms a soft magnetic film on a surface of a non-magnetic substrate having an area which is a multiple of the size of the recording medium to be formed, and thereafter Performing a step of cutting and separating the magnetic substrate into predetermined disk-shaped medium units to form a plurality of medium substrates, and a step of depositing and forming a perpendicular recording film on the soft magnetic film of each separated medium substrate. A plurality of double-layered magnetic recording media are formed.

Further, prior to forming the soft magnetic film on the surface of the non-magnetic substrate, the areas to be cut and separated for each medium unit on the surface of the non-magnetic substrate are previously processed into a rough surface having a large number of concentric concavo-convex lines. To configure.

[0012]

According to the present invention, the non-magnetic substrate surface having an area which is a multiple of the size of a small disk (recording medium) is provided with a rough surface having a large number of concentric circular uneven lines on the area to be cut and separated for each medium unit. And then a soft magnetic film is formed on the entire surface of the non-magnetic substrate by an electrolytic plating method or the like, and then the non-magnetic substrate on which the soft magnetic film is formed is roughened to form a large number of concentric concavo-convex streaks. By cutting (punching) into concentric disk-shaped medium units, a plurality of soft magnetic films having a high initial permeability having magnetic anisotropy are formed along the concentric concavo-convex lines. Since the medium substrate is formed, the complexity of manual work in these steps is eliminated, and the handling time is reduced.

By forming a perpendicular recording film on the surfaces of the plurality of cut and separated (punched) medium substrates by a continuous sputtering method, a plurality of small perpendicular magnetic recording media having excellent magnetic characteristics can be efficiently formed. You can get better.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIGS. 1 (a), (b) to 2 (a), (b) are views for explaining a first embodiment of a method of manufacturing a perpendicular magnetic recording medium according to the present invention. Is a perspective view, and each drawing (b) is a side sectional view.

First, as shown in FIG. 1 (a), a plurality of disc disks A can be cut out, for example, 500 mm × 50.
A nonmagnetic substrate 31 is prepared by performing NiP plating on the surface of an aluminum plate having a large area of 0 mm, and the nonmagnetic substrate 31 is filled with sulfuric acid in a plating bath 41 as shown in FIG. 1 (b). nickel (NiSO ₄ · 6H ₂ O) and ferrous sulfate (FeSO ₄ ·
(7H ₂ O) as the main component
It is disposed so as to face 43 and is electrically connected to one electrode of the plating power source 44.

The electrode plate 43 for plating and the non-magnetic substrate
A voltage of 4 to 5 V is applied between 31 and plating is performed under the plating conditions of a current density of 6 A / dm ² , and as shown in FIG. 2 (a), the surface of the non-magnetic substrate 31 is a Ni-Fe alloy with a film thickness of 1 μm. A soft magnetic film 32 made of a film is formed.

Next, the nonmagnetic substrate 31 after the plating is washed and mechanically punched into a predetermined disk medium size as shown in the figure, for example, 25 so-called 3.5-inch type having an outer diameter of 95 mm. By forming the medium substrate 33, the handling complexity and handling time in the plating process are reduced.

Here, each punched medium substrate 33 is mechanically polished to finish the punched peripheral portion and the like, if necessary. Then, as shown in FIG. 2 (b), the above-mentioned medium substrates 33 are sequentially fed into, for example, a continuous sputtering device 45 in which two Co-Cr targets 46 are opposed to each other, and the surface of each medium substrate 33 is subjected to a sputtering method. A perpendicular recording film made of a Co-Cr film with a thickness of 0.15 μm is formed on the surface of the film, and the film surface is lubricated and protected. Inch perpendicular magnetic disks can be obtained efficiently.

FIGS. 3 (a) and 3 (b) are perspective views for explaining a second embodiment of the method of manufacturing a perpendicular magnetic recording medium according to the present invention, and FIGS. 1 (a) and 2 (b). The same parts as those in FIG.

In the second embodiment, as shown in FIG. 3 (a), the medium is cut (punched) into individual medium units on the surface of a non-magnetic substrate 31 similar to the large-area non-magnetic substrate described in the first embodiment. A plurality of planned regions to be processed are previously processed into a rough surface having a large number of concentric concavo-convex streaks 31a.

This rough surface processing is carried out by pressing a rotating polishing plate 47, for example, while supplying a processing liquid, to a plurality of predetermined regions on the surface of the non-magnetic substrate 31 to be cut (separated) into individual medium units (punched). By doing so, it is possible to form a rough surface having a large number of concentric concavo-convex streaks 31a.

Next, on the surface of the non-magnetic substrate 31 processed into a rough surface, the same electrolytic plating method as in the first embodiment is used, as shown in FIG.
After forming the soft magnetic film 51 made of a Ni-Fe alloy film having a film thickness of 1 μm as shown in FIG. 3, the non-magnetic substrate 31 on which the soft magnetic film 51 is formed is shown in FIG. By cutting (mechanically punching) into a predetermined disk medium size so as to form a concentric circle with the concentric concavo-convex streak 31a that has been surface-processed, it is possible to have magnetic anisotropy along the concentric concavo-convex streak 31a. It is possible to form, for example, 25 medium substrates 52 of 3.5 inch type on which the soft magnetic film 51 having high magnetic permeability is formed.

Then, as in the first embodiment [FIG. 2 (b)], each of the above-mentioned medium substrates 52 is sequentially fed into the continuous sputtering device 45 in which two Co-Cr targets 46 are opposed to each other, and the sputtering method is performed. On each medium substrate 52 surface, 0.15μ
By forming a perpendicular recording film consisting of a Co-Cr film with a thickness of m, and applying a lubrication protection process to the film surface, multiple 3.5-inch small perpendicular magnetic disks with high write efficiency and uniform magnetic characteristics are provided. The disc can be obtained efficiently.

In the above embodiments, an example in which the electrolytic plating method is used as the method for forming the soft magnetic film made of the Ni--Fe alloy film has been described, but the present invention is not limited to such an example. However, similar effects can be obtained even when a sputtering method is used.

[0025]

As is apparent from the above description, according to the method for manufacturing a perpendicular magnetic recording medium of the present invention, an electrolytic plating method is applied to a large-area non-magnetic substrate surface from which a plurality of disk discs can be cut out, Alternatively, by forming a soft magnetic film made of a Ni-Fe alloy film by a sputtering method or the like, the complexity of handling in the film forming process is eliminated and the handling time is reduced.

Further, a plurality of predetermined regions to be cut (separated) into individual medium units on the large-area non-magnetic substrate surface are previously processed into a rough surface having a large number of concentric concavo-convex lines, and the non-magnetic substrate is formed. By forming a soft magnetic film consisting of a Ni-Fe alloy film on the surface by electrolytic plating or sputtering, the handling complexity in the film forming process is eliminated and the soft magnetic film with high initial permeability is formed. Is obtained.

Further, a perpendicular recording film made of a Co--Cr film is formed on the surfaces of a plurality of medium substrates obtained by cutting and separating the non-magnetic substrate on which the soft magnetic film is formed into a predetermined disk medium size, By subjecting the film surface to the lubrication protection treatment, it is possible to effectively obtain a plurality of small vertical magnetic disks having high writing efficiency and uniform magnetic characteristics, which are excellent in practical use.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a film forming process of a soft magnetic film in a first embodiment of a method of manufacturing a perpendicular magnetic recording medium according to the present invention.

FIG. 2 is a diagram for explaining a medium substrate forming step and a perpendicular recording film forming step in the first embodiment of the method of manufacturing a perpendicular magnetic recording medium according to the present invention.

FIG. 3 is a diagram for explaining a second embodiment of the method of manufacturing the perpendicular magnetic recording medium according to the present invention.

FIG. 4 is a schematic configuration diagram for explaining a conventional method of manufacturing a perpendicular magnetic recording medium.

[Explanation of symbols]

 31 non-magnetic substrate 31a concentric concavo-convex streaks 32,51 soft magnetic film 33,52 medium substrate 41 plating bath 42 plating solution 43 plating electrode plate 44 plating power supply 45 continuous sputtering device 46 Co-Cr target 47 polishing plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyuki Seki 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (2)

[Claims] 1. A soft magnetic film (32) is formed on a surface of a non-magnetic substrate (31) having an area which is a multiple of the size of a recording medium to be formed, and the non-magnetic substrate (31) is then formed into a predetermined disc. A step of forming a plurality of medium substrates (33) by cutting and separating each of the shaped medium units; and a step of forming a perpendicular recording film on the soft magnetic film (32) of each of the separated medium substrates (33). A method of manufacturing a perpendicular magnetic recording medium, comprising: 2. Prior to forming the soft magnetic film (51) on the surface of the non-magnetic substrate (31), a plurality of concentric circles are preliminarily formed on the non-magnetic substrate (31) surface in a region to be cut and separated for each medium unit. 2. The method of manufacturing a perpendicular magnetic recording medium according to claim 1, wherein the surface is processed into a rough surface having uneven lines (31a).