JPH0244522A - Production of perpendicular magnetic disk - Google Patents

Abstract

PURPOSE:To easily form a perpendicular recording layer which prevents head attraction by forming mesh-like electrodes on the surface of a soft magnetic layer on a substrate so as to face said layer, impressing a voltage between the soft magnetic layer and the mesh-like electrodes to form very small ruggedness on the surface of the soft magnetic layer and forming the perpendicular recording layer thereon. CONSTITUTION:A soft magnetic lining layer 13 having high magnetic permeability is formed on an underlying film 12 which is previously formed on the nonmagnetic disk substrate 11. The disk substrate 11 and the mesh-like electrodes 24 are then disposed to face each other in an electrolytic cell 21 filled with an electrolyte 22 and the voltage is impressed between the soft magnetic lining layer 13 and the mesh- like electrode 24 to effect electrolytic etching. A rough surface 24 having the very small ruggedness is then formed on the surface of the soft magnetic lining layer 13 corresponding to the net lines 24a of the mesh-like electrodes 24. The perpendicular recording layer 15, a protective film 16 and a lubricating film 17 are formed thereon. The perpendicular recording layer having the surface roughened to prevent the head attraction even if the soft magnetic lining layer 13 having the high magnetic permeability is formed thick regardless of the material of the disk substrate 11 is thereby easily formed.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a method of manufacturing a perpendicular magnetic disk suitable for use in a perpendicular magnetic recording type magnetic disk device, regardless of the material of the disk substrate, The purpose of this technology is to easily form a perpendicular recording layer with a desired roughened surface that prevents head adsorption on the soft magnetic layer even if the layer (layer) is made thicker, and has high magnetic permeability on the disk substrate. A soft magnetic layer is formed, mesh electrodes are arranged opposite to each other on the surface thereof, a voltage is applied between the soft magnetic layer and the mesh electrode, and the surface of the soft magnetic layer is made to have minute irregularities by electrolytic processing and nching. Make the surface rough. Alternatively, on the disk substrate, a plurality of needle-like electrodes provided in at least one row in the radial direction are arranged facing each other at a predetermined interval, and a voltage is applied between the disk substrate and the plurality of needle-like electrodes. After forming a high permeability soft magnetic layer made of a plating layer having a rough surface with minute irregularities corresponding to the plurality of needle electrodes, a perpendicular recording layer is formed on the rough surface of the soft magnetic layer. It is configured to form.

[Industrial application field]

The present invention relates to a method of manufacturing a perpendicular magnetic disk suitable for use in a perpendicular magnetic recording type magnetic disk device, and in particular, to
The present invention relates to a method for manufacturing a perpendicular magnetic disk having a double-layer structure and having good sliding characteristics that prevents the magnetic head from being attracted during S (Contact 5-tart-5-top) operation.

In a magnetic disk drive, when the rotation of the magnetic disk is stopped, the magnetic head is in contact with the disk surface, and as the rotational speed of the magnetic disk increases, the magnetic head lifts from sliding and maintains a constant distance. The C8S method for recording and reproducing information is widely used.

In such a C8S method, since the magnetic head comes into contact with and slides on the magnetic disk surface at a relatively long distance before it floats above the surface, in order to prevent frictional damage to the magnetic head and the magnetic disk surface, A lubricating film or the like is applied to the surface of the magnetic disk.

If the surface of the magnetic disk coated with this lubricating film is too smooth, the magnetic head tends to stick to the opposing disk surface during C8S operation, causing a head crash. Therefore, there is a need for a method of manufacturing a perpendicular magnetic disk that does not cause head attraction during C8S operation and has excellent crash resistance.

[Conventional technology]

As shown in FIG. 10(a), the conventional method for manufacturing perpendicular magnetic disks with crush resistance that prevents head adsorption during C8S operation, etc. is to first mechanically coat the surface of the disk substrate 1 using a wrapping tape or the like. Rough surface processing (
After creating a rough surface 2 with minute irregularities (0.1 μm or less) using the texturing method, the 10th
As shown in Figure (b), the surface of the substrate 1 is coated with Ni-Fe.
A high magnetic permeability soft magnetic layer (hereinafter referred to as soft magnetic backing layer) 3 having a film thickness of, for example, 0.5 μm and Co-Cr.
A perpendicular recording layer 4 having a film thickness of 0.2 μm is sequentially formed by plating, sputtering, or the like.

As shown in FIG. 10(C), a protective film 5 and a lubricating film 6 are applied to the surface of the perpendicular recording layer 4 in order to reduce friction and wear when the magnetic head contacts and slides.

The reason why the surface of the disk substrate 1 is made into a rough surface 2 is that when a soft magnetic backing layer 3, a perpendicular recording layer 4, a protective film 5, and a lubricating film 6 are sequentially deposited on the rough surface 2, the lubricating film As shown in FIG. 10(C), the top surface on which No. 6 has been applied is a surface that inherits the rough surface condition of the surface of the disk substrate 1, and this surface condition reduces the contact area with the magnetic head, and the head Adsorption is prevented, the thickness of the lubricating film is maintained at an appropriate level, and low friction and wear on the magnetic head are maintained.

[Problems to be Solved by the Invention] As described above, the surface of the disk substrate 1 is made into a rough surface 2 by mechanical roughening pressure (also called texturing method) in order to prevent head adsorption, etc. When the disk substrate 1 is made of NiP or glass, which is relatively harder than aluminum, aluminum alloy, etc., the surface roughness can be controlled when the surface is mechanically roughened. is difficult.

In addition, the soft magnetic backing layer 3 with high magnetic permeability in the perpendicular magnetic disk with the above-mentioned two-layer film structure suppresses the polarization magnetic charge generated on the back surface of the perpendicular recording layer 4 during recording and reproduction, and reduces the perpendicular demagnetization field. This prevents magnetization from decreasing and also forms a return path for the magnetic flux to the magnetic head, so it plays a part in the function of the magnetic head to improve recording and reproducing efficiency, and in order to obtain better recording and reproducing characteristics. is required to increase its film thickness.

Therefore, when the thickness of the soft magnetic underlayer 3 is increased to the order of microns, the surface condition becomes less likely to become a minute uneven surface that inherits the rough surface formed on the surface of the disk substrate 1. This phenomenon is particularly noticeable when forming a thick soft magnetic backing layer using a plating method that has a high deposition rate, so the effect of the rough surface of the disk substrate does not appear on the outermost surface of the disk. , there was a problem that the effect of preventing head adsorption was lost.

In view of the above-mentioned conventional problems, the present invention provides a desired method for preventing head adsorption onto a soft magnetic backing layer with high magnetic permeability, regardless of the material of the disk substrate and even if the soft magnetic backing layer with high magnetic permeability is thickened. It is an object of the present invention to provide a novel method for manufacturing a perpendicular magnetic disk that can easily form a perpendicular recording layer having a roughened surface.

[Means to solve the problem]

In order to achieve the above object, in the manufacturing method according to the first invention, a soft magnetic backing layer is formed on a disk substrate, mesh electrodes are arranged facing each other on the surface of the soft magnetic backing layer, and a gap between the soft magnetic backing layer and the mesh electrode is provided. After applying a voltage to perform electrolytic etching to make the surface of the soft magnetic backing layer rough with minute irregularities corresponding to the mesh of the mesh electrode, perpendicular recording is performed on the rough surface of the soft magnetic backing layer. The composition is configured to form a layer.

Further, in the manufacturing method according to the second invention, in the step of forming a soft magnetic under layer in a perpendicular magnetic disk in which a soft magnetic under layer and a perpendicular recording layer are sequentially laminated on a disk substrate, at least 1
A plurality of needle-like electrodes provided in a row are arranged facing each other at a predetermined interval, and a voltage is applied between the disk substrate and the plurality of needle-like electrodes on the disk substrate, corresponding to the plurality of needle-like electrodes. The soft magnetic backing layer is formed of a plating layer having a rough surface with minute irregularities.

[For production]

In the manufacturing method of the first invention, a high permeability soft magnetic backing layer made of, for example, Ni-Fe formed on a disk substrate is used as an anode, a mesh electrode arranged facing each other is used as a cathode, and a voltage is applied between the two. When electrolytic etching is performed, the soft magnetic backing layer portion corresponding to the mesh portion of the mesh electrode is electrochemically melted at a faster rate than other mesh portions and selectively etched. The surface of the soft magnetic underlayer becomes a rough surface with minute irregularities.

Further, in the manufacturing method of the second invention, a plating layer (soft magnetic backing layer) made of, for example, Ni-Fe is formed on the disk substrate by applying a voltage between a plurality of needle-like electrodes arranged facing each other at a predetermined distance from the disk substrate. When formed, the deposition rate on the surface part of the disk substrate corresponding to the tip of each needle electrode is faster than on other surface parts, so the thickness of the plating layer differs partially, and the formed plating layer The surface of the (soft magnetic underlayer) is roughened into minute irregularities.

Therefore, by forming a perpendicular recording layer on the rough surface of the soft magnetic backing layer described above, a surface that inherits the rough surface with minute irregularities can be created without being affected by the thickness of the soft magnetic backing layer. A perpendicular recording layer can be easily formed.

As a result, a perpendicular magnetic disk with low friction and good sliding characteristics without head attraction is obtained.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of an electrolytic etching apparatus for explaining an embodiment of the method for manufacturing a perpendicular magnetic disk according to the first aspect of the present invention.

In this example, N
Nickel sulfate (NiS04.6H20) and ferrous sulfide (Fe
Using a plating solution whose main component is SO, 7H20),
Voltage: 5. A thick soft magnetic backing N13 made of Ni-Fe with a thickness of 2 to 3 μm and having high magnetic permeability is formed under the plating conditions of OV, current density: 68/da''.

Next, as shown in FIG. 1, for example, the Ni-Fe plating solution may be used as an electrolyte, or an electrolyte 22 such as a phosphoric acid electrolyte may be used.
The disk substrate 11 on which the soft magnetic backing layer 13 is formed, which is attached to the substrate support 23, and the mesh electrode 24 are arranged facing each other with an interval of, for example, about 0.1μ in an electrolytic bath 21 filled with , the soft magnetic underlayer 13 is an anode;
Electrolytic etching is performed by applying a voltage between the mesh electrode 24 as a cathode and the two electrodes.

The mesh electrode 24 may have a mesh opening of 0.1, for example.
1! A lid (Cu) mesh plated with nickel is used, the electrolytic current is set to 175, and the current application time is set to about <1/10 of that of the Ni-Fe plating.

(Then, as shown in FIG. 2, the surface portion of the soft magnetic underlayer 13 corresponding to the mesh lines 24a of the mesh electrode 24 is selectively electrolytically etched with respect to the mesh 24b portion, and as shown in FIG. A rough surface 14 having minute irregularities is formed as shown in FIG.

Therefore, as shown in FIG. 4, a perpendicular recording layer 15 made of, for example, Co-Cr and having a thickness of 0.2 μm is formed on the rough surface 14 of the soft magnetic underlayer 13 by sputtering or the like. Furthermore, a protective film 16 and a lubricating film 17 are applied to reduce friction and wear when the magnetic head contacts and slides, thereby forming a soft magnetic backing layer 13 with high magnetic permeability.
Even if the film thickness of
It is possible to easily form the perpendicular recording layer 15 having a surface inherited from the above, as well as the protective film 16 and the lubricating film 17.

Further, FIG. 5 is a schematic diagram of a plating apparatus for explaining an embodiment of a method for manufacturing a perpendicular magnetic disk according to the second aspect of the present invention.

In this example, as shown in the figure, nickel sulfate (NiSO E 61120) and ferrous sulfide (FeSO4.7HzO) were used.
A plating bath 4 filled with a plating solution 42 mainly composed of
1, a non-magnetic disk substrate 31 made of glass or the like on which a plating base film 32 made of Ni--Fe has been formed in advance by sputtering or the like on the surface, which is attached to a substrate support 43; The plating base film 32 on the disk substrate 31 is arranged to face a plurality of tungsten (-) needle electrodes 44 provided in one or more rows in the radial direction with a predetermined interval (for example, about 1 μm interval). (anode) and multiple needle-like electrodes 44 (anode)
A voltage of 4 to 5 μm is applied between these steps, and a Ni--Fe plating layer with a thickness of 2 to 3 μm is formed on the disk substrate 31 at a current density of 50 mA/cm.

Since insoluble tungsten needles are used as the plurality of needle electrodes 44 to form a uniform rough surface, components such as Ni and Fe in the plating solution during plating are reduced. The plating solution 42 in the plating bath 41 is constantly replenished with new plating solution.

The plating operation involves plating a plurality of needle-like electrodes 4 provided in one or more rows in the radial direction of the disk substrate 31.
Plating is performed by rotating the disk substrate 31 facing the substrate 4 by a predetermined step width at regular intervals.

In this way, as shown in FIG. 6, the plating film formation rate on the surface portion of the plating base film 32 on the disk substrate 31 corresponding to the tip of each needle electrode 44 is faster than on other surface portions. The thickness of the plating layer is partially different, and the soft magnetic backing layer 33 is made of a plating layer formed as shown in FIG.
The surface becomes a rough surface 34 having minute irregularities.

Therefore, as shown in FIG.
A perpendicular recording layer 35 made of, for example, Co-Cr is formed on the rough surface 34 to a thickness of 0.2 μm by sputtering or the like.
By completing the protective film 36 and lubricating film 37 to reduce wear, the soft magnetic underlayer 3 with high magnetic permeability is formed.
Even if the film thickness of 3 is increased, it will not be affected by the thickness (
On the soft magnetic backing layer 33, the rough surface 3 with minute irregularities is formed.
It is possible to easily form a perpendicular recording layer 35 having a surface similar to that of 4, as well as a protective film 36 and a lubricating film 37.

In the above embodiment, the disk substrate 31 facing the plurality of needle electrodes 44 provided in one or more rows in the radial direction of the disk substrate 31 is rotated by a predetermined step width at regular intervals. Although an example in which plating is performed has been described, the disk substrate 31 may be fixed and the plurality of opposing needle-like electrodes 44 may similarly be rotated by a predetermined step width at regular intervals. Further, plating may be performed while moving either the plurality of needle-shaped electrodes 44 or the disk substrate 31 at a low speed in the rotational direction of the disk substrate 31. In this case, as shown in FIG. 8, a soft magnetic backing layer 33a having a rough surface 34a with minute irregularities is formed in the radial direction of the disk substrate 31, and a similar effect can be obtained.

Alternatively, plating may be performed by arranging a plurality of needle-like electrodes facing each other at predetermined intervals over the entire surface of the disk substrate 31. Furthermore, the roughness of the rough surface 34 on the surface of the soft magnetic underlayer 33 is as follows:
This can be controlled by changing the density at which the plurality of needle electrodes 44 are arranged facing each other with respect to the surface of the disk substrate 31.

〔Effect of the invention〕

As is clear from the explanation below, the first. According to the method for manufacturing a perpendicular magnetic disk according to the second invention, the surface of the soft magnetic underlayer with high magnetic permeability formed on the disk substrate
A perpendicular recording layer having a rough surface with a desired roughness on the soft magnetic backing layer, which can be formed into a rough surface with appropriate minute irregularities without being affected by the thickness of the soft magnetic backing layer. Films etc. can be easily formed.

Therefore, it is possible to prevent adhesion failure of the magnetic head, and to obtain a highly reliable perpendicular magnetic disk having low friction and low abrasion properties, and other practical effects are achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an electrolytic etching apparatus for explaining an embodiment of the method for manufacturing a perpendicular magnetic disk according to the first invention, and FIG. 2 is a diagram illustrating electrolytic etching using a wire-like electrode in the first invention. FIG. 3 is a partial perspective view for explaining the finely uneven rough surface of the soft magnetic underlayer surface according to the first invention; FIG. 4 is a perpendicular magnetic disk according to the first invention. FIG. 5 is a schematic plating apparatus diagram for explaining an embodiment of the method for manufacturing a perpendicular magnetic disk according to the second aspect of the present invention; FIG. FIG. 6 is an enlarged cross-sectional view of a main part to explain plating with a needle-shaped electrode in the second invention, and FIGS. 7 and 8 illustrate a finely uneven rough surface on the surface of a soft magnetic backing layer according to the second invention. FIG. 9 is a cross-sectional view of essential parts for explaining an embodiment of the method for manufacturing a perpendicular magnetic disk according to the second invention. FIGS. FIG. 3 is a cross-sectional view of main parts for explaining a method for manufacturing a disk in order of steps. 1 to 9, 11.31 is a disk substrate, 12.32 is a plating base film, 13.33 is a soft magnetic backing layer, 14.34° 34a is a rough surface, 15.35 is a perpendicular recording layer, 16.36 is a protective film,
17.37 is a lubricating film, 21 is an electrolytic cell, 22 is an electrolytic solution, 2
3.43 is a substrate support, 24 is a mesh electrode, 24a is a mesh wire, 24b is a mesh, 41 is a plating bath, 42 is a plating solution, and 44 is a needle electrode. Figure Figure Figure O Ij Thursday September Tsuru 4-! tΣJ-97, 6 million faces, 1 multi-face; Yobuko ν2 figure 3 figure figure

Claims (3)

[Claims] (1) High permeability soft magnetic layer (
A mesh electrode (24) is placed on the surface of the soft magnetic layer (13), and a voltage is applied between the soft magnetic layer (13) and the mesh electrode (24), and the soft magnetic layer (13) is electrolytically etched.
After making the surface of the soft magnetic layer (13) into a rough surface (14) having minute irregularities, a perpendicular recording layer (15) is formed on the rough surface (14) of the soft magnetic layer (13).
) A method for manufacturing a perpendicular magnetic disk, the method comprising: (2) High permeability soft magnetic layer (
33) and a perpendicular recording layer (35) formed in order in a perpendicular magnetic disk medium in which a plurality of soft magnetic layers (33) are formed in at least one row in the radial direction on the disk substrate (31). Book needle-shaped electrode (44)
The disk substrates (31
) and the plurality of needle-like electrodes (44), and the plurality of needle-like electrodes (44) are placed on the disk substrate (31).
) A method for manufacturing a perpendicular magnetic disk, characterized by forming a high permeability soft magnetic layer (33) made of a plating layer having a rough surface (34) with minute irregularities corresponding to the above. (3) A plurality of needle electrodes (44) facing the disk substrate (31) are moved stepwise or continuously in the circumferential direction of the disk substrate (31). 2.) Manufacturing a perpendicular magnetic disk according to claim 2, wherein a high permeability soft magnetic layer (33) made of a plating layer having a rough surface (34) with minute irregularities is formed thereon. Method.