JPH03201218A - Production of perpendicular magnetic recording disk medium - Google Patents

Abstract

PURPOSE:To reduce variation in output on readout by disposing a plane helical coil at the back of a substrate during formation of a base layer having high magnetic permeability, and then applying a magnetic field having a magnetic field component almost uniform and parallel to the substrate plane. CONSTITUTION:When an electric current is caused to flow in a plane coil 21, a magnetic field 22 appears near the surface of the coil, redially expanding as shown by arrows in the figure. When the magnetic field is decomposed into the perpendicular component and parallel component to the plane of the disk medium in the cross sectional view of the coil, distribution of the parallel component can be regarded almost uniform within the radius of the disk. Therefore, by forming a layer of high magnetic permeability in this applied magnetic field, the perpendicular component of the magnetic field can be neglected by the shape anisotropy of the layer of high magnetic permeability itself. Thereby, a base layer of high magnetic permeability having the axis of easy magnetization oriented in the radial direction can be effectively formed, and the variation in output on readout can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a magnetic disk medium having a perpendicular magnetic recording layer and a high permeability underlayer.

Problems to be Solved by Conventional Technologies and Inventions Magnetic recording methods generally include longitudinal recording methods and perpendicular recording methods.Perpendicular recording methods allow for higher recording densities, so research and development of this recording method is required. , and the production of recording media using this method is actively carried out.

Regarding this perpendicular magnetic recording method, conventionally, when manufacturing a perpendicular magnetic recording disk medium having a high magnetic permeability underlayer, the output during readout is improved by aligning the axis of easy magnetization of the high magnetic permeability underlayer in the radial direction. A method of suppressing fluctuations has been devised, and various methods have been devised to achieve this. For example, JP-A-60-52909, JP-A-61
-177633, Japanese Patent Application Laid-Open No. 62-129940, etc., as shown in FIG. 1, a permanent magnet 11 and an auxiliary ferromagnetic body 12 are provided on a substrate holder, and a radial horizontal magnetic field 13 is applied to the substrate. The method is to do so. but,
This method has a drawback in that no consideration is given to the influence of the horizontal magnetic field 13 when the perpendicular magnetic recording layer is fabricated by sputtering.

Furthermore, Japanese Patent Application Laid-Open No. 62-205518 discloses a method in which a permanent magnet or an electromagnet is rotated on the back side of a substrate holder. However, this method is inefficient when considering actual disk media manufacturing.

Furthermore, all of these methods have the disadvantage that no consideration is given to application to in-line sputtering equipment used in actual disk media manufacturing.

In other words, in the actual manufacturing of disk media, it is essential to form a film on both sides, but in the conventional method, a magnetic field generation mechanism is built into the substrate holder itself, so in order to form a film on both sides, the disk medium must be removed once. This is undesirable because it requires a special mechanism and effort to remove the board from the holder and turn it over.

Furthermore, providing a magnetic material and an uneven portion in the portion facing the target in the in-line sputtering device makes maintenance management difficult and increases maintenance costs.

Therefore, the object of the present invention is to solve the above-mentioned conventional drawbacks and
It is an object of the present invention to provide a method of manufacturing a perpendicular magnetic disk medium with little output fluctuation during reading by aligning the axis of easy magnetization of a high magnetic permeability underlayer in the radial direction of the substrate in a form that can be applied to actual manufacturing.

Means for Solving the Problems The present invention uses only a helical planar coil to generate a radial DC magnetic field, does not require any auxiliary ferromagnetic material, and also provides a substrate tray and a coil for an in-line sputtering device. It is characterized by a separate movable pallet.

Example Examples according to the present invention will be described below.

First, the planar coil will be explained. FIG. 2 shows an example of a bird's-eye view and a cross-sectional view of a planar coil. For example, when this planar coil is used for a 130 mm substrate, it suffices to have a disk shape with a central hole diameter of about 20 mm and an outer diameter of about 150111111 mm and a predetermined thickness. When a current is passed through the planar coil 21, a magnetic field 22 that spreads radially as shown by arrows is generated near its surface.

FIG. 3 shows the magnetic field shown in FIG. 2 broken down into a vertical component 31 and a horizontal component 32 with respect to the disk medium surface when viewed from the cross-sectional direction of the coil. The vertical component 31 is shown by a dotted line, and the horizontal component 32 is shown by a solid line.

Further, a portion corresponding to the radius of the disk medium is indicated by 33.

What should be noted here is that the distribution of the horizontal component 32 of the magnetic field is approximately uniform within the radius 33 of the disk medium. Due to this fact, if a high permeability layer is fabricated in this applied magnetic field, the vertical component 31 of the applied magnetic field can be almost ignored due to the shape anisotropy of the high permeability layer itself, and the horizontal component 32 of the applied magnetic field Due to the effect of the magnetization, the axis of easy magnetization can be uniformly aligned in the radial direction of the disk medium, eliminating the need for an auxiliary ferromagnetic material that makes maintenance of the device difficult.

Another great advantage is that the magnitude of the magnetic field can be changed freely depending on the magnitude of the current flowing, and that coils can easily create a uniform magnetic field compared to permanent magnets.

Furthermore, the planar coil can be made extremely thin, and the space required for the radial magnetic field generation mechanism can be significantly reduced.

Next, the movable pallet for planar coils will be explained. Fourth
The figure shows a movable pallet for planar coils.

The planar coils 21 are arranged on the movable pallet 41 by the number of substrates so as to coincide with the centers of the disk medium substrates 43 on the substrate tray 42. The planar coil 21 is
It is connected to a DC power source 44 via a resistor 45 (not shown for simplicity).While this pallet 41 moves in synchronization with the substrate tray 42, a high magnetic permeability layer is formed on the opposite surface. This will result in sputtering.

As mentioned above, in the prior art, no consideration was given to application to in-line sputtering equipment used in actual manufacturing.

On the other hand, in the present invention, since the movable pallet for the planar coil is completely separated from the substrate holder, there is no adverse effect during sputtering of the perpendicular magnetic recording layer, and there is no effect on the production speed. , and the perpendicular magnetic recording layer can now be produced by conventional double-sided sputtering.

Next, embodiments of the present invention will be described in detail using drawings. Fifth
The figure shows an example in which the present invention is applied to an in-line sputtering device. When the substrate tray 42 enters the high magnetic permeability layer sputtering bath 51, it is accompanied by the movable pallet 41 and passes in front of the high magnetic permeability layer target 52 while applying a radial magnetic field to each disk medium. After passing through the tank and completing film formation on one side, the movable pallet 41 moves away from the substrate tray 42, returns to the initial position, and waits for the next substrate tray to arrive. It is also possible to provide a plurality of these movable pallets 41 in one tank and use them sequentially.

When the substrate tray enters the next high permeability layer sputtering tank 51b, a similar operation is performed with the movable pallet 41b on the opposite side. This process makes it possible to fabricate high magnetic permeability layers on both sides of the substrate, the axes of easy magnetization aligned in the radial direction of the substrate, without affecting the manufacturing speed.

As described in detail, the method of the present invention makes it possible to efficiently produce a high magnetic permeability underlayer in which the axis of easy magnetization is aligned in the radial direction, thereby reducing output fluctuations during readout. This makes it possible to manufacture an excellent perpendicular magnetic recording disk medium with a small amount of damage.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an overview of the method according to the prior art, Fig. 2 is a bird's-eye view and cross-sectional view of a planar coil, and a diagram showing a magnetic field that spreads radially from the center generated near the surface of the planar coil. Regarding the magnetic field in Figure 2, a diagram showing the vertical component and horizontal component of the magnetic field with respect to the disk medium surface when viewed from the cross-sectional direction of the disk medium, Figure 4 is a diagram showing a movable pallet for a planar coil, FIG. 5 is a diagram showing an example in which the present invention is applied to an in-line sputtering apparatus. 11...Permanent magnet, 12...Auxiliary ferromagnetic material,
13... Radial magnetic field, 21... Planar Koinope 2
2... Radial magnetic field, 31... Vertical component of magnetic field,
32...Horizontal component of magnetic field, 33...Disk medium substrate radius, 41...Movable balent for coil, 42...Substrate tray, 43...Disk medium substrate, 5L51b... ...High magnetic permeability layer sputtering bath, 52
...High permeability magnetic material target. 1 Figure 1

Claims (2)

[Claims] (1) In a method of manufacturing a magnetic recording disk medium having a perpendicular magnetic recording layer and a high magnetic permeability underlayer using a sputtering method, when forming the high magnetic permeability underlayer, it is wound spirally on the back side of the substrate. A method for manufacturing a perpendicular magnetic recording disk medium, characterized in that a substantially uniform magnetic field component parallel to a substrate surface of a magnetic field generated by arranging a flat coil and applying a direct current to the coil is applied. (2) In the in-line sputtering production equipment, a movable pallet with planar coils arranged is installed separately from the substrate tray, and by moving the pallet in synchronization with the substrate tray, it is possible to move the pallet onto the substrate only during the deposition of the high magnetic conductivity underlayer. 2. The method of manufacturing a perpendicular magnetic recording disk medium according to claim 1, wherein a uniform radial magnetic field is applied.