JPH044531B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic disk for a rotary encoder, and in particular, a method for manufacturing a magnetic disk for a rotary encoder, in which a magnetic thin film of uniform thickness is formed on a disk-shaped substrate by a sputtering deposition method. The present invention relates to a method of manufacturing a magnetic disk.

[Prior art and problems to be solved]

Conventional magnetic disks for rotary encoders are made by sintering magnetic powder into a disk shape or by processing a magnetic alloy into a disk shape.
1 is made entirely of a magnetic material, and as shown in FIGS. 4a and 4b, a magnetic disk 21 has magnetic patterns 23 formed by magnetizing the side surface or the periphery of the surface at predetermined intervals, as shown in FIGS. There is.

However, since magnetic materials are generally expensive, hard and difficult to process, the magnetic disk 21 made entirely of magnetic material is expensive and difficult to manufacture. The problem was that it was not suitable for mass production.

On the other hand, a disk-shaped substrate 22 is formed of a material that is easy to process, such as aluminum, and a magnetic powder containing rare earth elements such as samarium cobalt and neodymium as a main component is applied to the disk-shaped substrate 22. A magnetic paint 24 mixed in a binder is applied to form a magnetic disk 21, and this magnetic paint 24 is coated to form a magnetic disk 21.
It is known that magnetic patterns 23 are formed on the side surface or peripheral edge of the surface of a magnetic disk 21 coated with a magnetic disk 21 by magnetizing it at predetermined intervals as shown in FIGS. 5a and 5b.

As described above, the magnetic disk 21 in which the magnetic paint 24 is coated on the surface of the disk-shaped substrate 22 has the advantage that it is cheaper and has better workability than a disk made entirely of magnetic material. However, there is a problem in that the magnetic layer formed from the magnetic paint 24 in which magnetic powder is mixed into the resin binder is sensitive to high temperatures and has poor temperature characteristics.

In order to solve each of the above-mentioned problems, we focused on a method of forming a magnetic thin film of ferromagnetic material on the surface of a disk-shaped substrate by sputtering deposition.

The above-mentioned sputtering vapor deposition method has the advantage that the adhesion force between the substrate and the magnetic thin film is large and that the alloy of ferromagnetic materials can be deposited on the substrate without significantly changing the alloy composition. The inventors investigated the magnetron sputtering method, which has excellent ion generation efficiency among sputtering vapor deposition methods, and investigated the most common type among them, the planar type.

In the flat plate type magnetron sputtering method, the structure is as shown in FIGS. 6a and 6b,
FIG. 6a shows the effect when a non-magnetic material is used for the target 33, and FIG. 6b shows the effect when a ferromagnetic material is used for the target 33.

First, in the case shown in FIG. 6a, the S pole and the N pole are arranged on the lower surface of the target 33 made of a non-magnetic material so that the magnetic lines of force 35 form an arch on the upper surface side of the target 33. Magnets 34 are arranged at intervals and set to form an electric field 37 vertically from above to below the target 33, and in an atmosphere of a discharge gas 38 such as argon, electrons generated from the target 33 are The positive ions that are efficiently trapped inside the magnetic field 36 indicated by the magnetic lines of force 35 and ionize the discharge gas 38 by the electrons are improved in production efficiency, and multiple positive ions are made to collide with the target 33. It is deposited by sputtering.

On the other hand, in the case where a ferromagnetic material is used as the target 33 shown in FIG.
Since the magnetic circuit is shot between the magnet 34 provided on the lower surface of the target 33 and the magnetic field 36 is not formed on the upper surface of the target 33, the electrons generated from the target 33 as described above cannot be captured. The production efficiency of the magnetic thin film by sputtering deposition is poor, and the electrons reflected by the target 33 collide with the magnetic thin film formed on the substrate, damaging the magnetic thin film. was not applicable.

The present invention solves the problems of the conventional disks as described above, and has superior workability, better temperature characteristics, and can be manufactured at a lower cost than when the entire magnetic disk is made of magnetic material. A magnetic thin film with a uniform thickness is formed by sputtering deposition using a ferromagnetic material as a target.
The object of the present invention is to provide a method for manufacturing a magnetic disk for a rotary encoder, which allows mass production of products having a uniform and high-quality magnetic thin film.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a facing target sputtering method in which a magnetic field and an electric field are simultaneously applied between a pair of targets made of ferromagnetic materials that are disposed facing each other at a predetermined interval to perform sputtering deposition. on the side of the device between the targets;
A plurality of disk-shaped substrates are stacked one on top of the other with their centers located on one axis (X-axis) to form a substantially cylindrical body, and the substantially cylindrical body is aligned with the one axis (X-axis).
At the same time, the axis passing through the one axis (X axis) and extending between the targets is set as the other axis (Y axis), and the other axis (Y axis) is rotated.
It has means for performing sputtering deposition while rotating the other axis (Y-axis) eccentrically.

[Effect]

By employing the above-mentioned means, the present invention can simultaneously form magnetic thin films of ferromagnetic material on at least the side surfaces of a plurality of disk-shaped substrates, and the magnetic thin films simultaneously formed on the plurality of disk-shaped substrates are uniform. It is formed to have a certain thickness.

〔Example〕

Embodiments of the present invention shown in the drawings will be described below.

FIGS. 1a, b, and c show an opposed target sputtering device used in the method of manufacturing a magnetic disk for a rotary encoder according to the present invention.
A pair of targets 3, 3 made of a ferromagnetic material such as FeCrCo alloy are disposed vertically opposite each other at a predetermined interval, and magnetic lines of force 5 are perpendicular to the surfaces of the pair of opposing targets 3, 3, respectively. A pair of magnets 4, 4 are disposed on opposite sides of the opposing surfaces of the targets 3, 3, respectively, so as to form a magnetic field 6.

Furthermore, on the sides between the targets 3 and 3, as shown in FIGS. (15 sheets) are stacked one on top of the other at a predetermined interval with their centers located on one axis (hereinafter referred to as the This substantially cylindrical body 2' is made rotatable around the X-axis, and an axis passing through the X-axis and extending between the targets 3 and 3 is centered around the other axis (hereinafter referred to as the Y-axis). Furthermore, the Y-axis can be eccentrically rotated so as to draw a trajectory of the Y-axis as shown in FIG. 1c.

Further, a lamp heater 9 for heating the disk-shaped substrate 2 is disposed on the opposite side of the disk-shaped substrate 2 from the targets 3, 3, and the entire body is depressurized by a vacuum pump (not shown) to discharge a discharge gas 8.
It is possible to form an atmosphere and to form an electric field 7 between the pair of targets 3 in the direction of the arrow to perform sputtering deposition.

The disk-shaped substrate 2 may be made of a non-magnetic material such as aluminum or a magnetic material, and a material that is inexpensive and easy to process can be appropriately selected.

Next, the operation of the above will be explained.

In the facing target type sputtering apparatus configured as described above, the inside of the apparatus is brought into a predetermined reduced pressure state by a vacuum pump (not shown), a discharge gas 8 atmosphere is created, and the target 3,
When sputtering is started by setting the magnetic field 6 and the electric field 7 to act simultaneously between the targets 3 and 3, electrons 10 are first emitted from the targets 3, and these electrons 10 are emitted by the magnetic field 6 and the electric field 7. It is efficiently captured and confined between the targets 3, 3, and moves the targets 3, 3 in a cycloidal motion around the magnetic lines of force 5, ionizing the discharge gas 8 and generating many positive ions. The positive ions collide with the targets 3, 3 to generate thin film forming atoms from the targets 3, 3 made of ferromagnetic material.

On the other hand, on the side between the targets 3 and 3, 15
A substantially cylindrical body 2' formed of two disc-shaped substrates 2 is
While rotating around the X axis, the Y
Since the target rotates around the axis and the Y-axis rotates eccentrically, the atoms forming the thin film made of ferromagnetic material coming out of the pair of targets 3, 3 are
The magnetic thin film 12 made of a ferromagnetic material is uniformly adhered to each side surface and the peripheral edge of each surface of the 15 disk-shaped substrates 2, as shown in FIG. A large number of high-quality magnetic disks 1 can be manufactured at the same time.

Then, a magnetic pattern 11 having a predetermined magnetization pitch is formed on the magnetic thin film 12 of the magnetic disk 1 obtained above, as shown in FIGS. 3a, b, and c, so that it can be used as a rotary encoder.

The one shown in FIG. 3a above has the magnetic thin film 12 on both the side surface and the peripheral edge of the magnetic disk 1 magnetized, and the one shown in FIG. 3b has the magnetic thin film 12 on the side surface of the magnetic disk 1 magnetized. The one shown in FIG.
Only the magnetic thin film 12 at the peripheral edge of the surface of the magnetic thin film 12 is magnetized, and any of these can be employed in the method of the present invention.

By using the method described above, the present invention can select an appropriate material that is inexpensive and has good workability for the disk-shaped substrate 2, thereby reducing the overall cost, and since no resin binder is used, it has good temperature characteristics. In addition, compared to flat plate sputtering, the efficiency of sputtering deposition can be improved, and magnetic thin films of uniform thickness can be formed on multiple disk-shaped substrates at the same time, making it possible to mass produce high-quality rotary encoder products. It will be possible.

〔Effect of the invention〕

By adopting the above-mentioned means, the present invention has the following features:
Compared to flat plate sputtering, the efficiency of sputtering deposition can be improved, and magnetic thin films of uniform thickness can be formed on multiple disc-shaped substrates at the same time, making it possible to mass produce high-quality magnetic discs, and processing the disc-shaped substrates at low cost. Since an appropriate material with good properties can be selected, the overall cost can be reduced, and since a resin binder is not used, a magnetic disk with good temperature characteristics can be obtained.

[Brief explanation of drawings]

Figures 1a, b, and c show an opposed target sputtering device used in the method of manufacturing a magnetic disk for a rotary encoder according to the present invention;
is a schematic explanatory drawing, FIG. 1b is a view taken along line A-A in FIG. 1a and seen in the arrow direction, FIG. 1c is a diagram showing FIG. 1a
FIG. 2 is a perspective view of a magnetic disk manufactured according to the present invention, FIG. 3 a,
b and c are perspective views of magnetic disks in which different types of magnetic patterns are magnetized to the magnetic disk in Fig. 2, and Fig. 4 a and b are perspective views of different types of magnetic disks manufactured by one conventional manufacturing method. 5th perspective view of a magnetic disk magnetized with a magnetic pattern of
Figures a and b are perspective views of magnetic disks manufactured by other conventional manufacturing methods and magnetized with different types of magnetic patterns, and Figures 6 a and b are explanatory diagrams of the operation of a conventional sputtering device. FIG. 6a is an explanatory view showing the effect when a non-magnetic material is used as the target, and FIG. 6b is an explanatory view showing the effect when a magnetic material is used as the target. 1, 21... Magnetic disk, 2, 22... Disc-shaped substrate, 2'... Approximately cylindrical body, 3, 33... Target, 4, 34... Magnet, 5, 35... Lines of magnetic force, 6, 36... ...Magnetic field, 7,37...Electric field, 8,
38...Discharge gas, 9...Lamp heater, 10...
...electron, 11,23...magnetic pattern, 12...
Magnetic thin film, 24...magnetic paint, X axis...one axis, Y axis...the other axis.

Claims (1)

[Claims] 1. The side between the targets of a facing target sputtering apparatus that performs sputtering deposition by simultaneously applying a magnetic field and an electric field between a pair of targets made of ferromagnetic materials arranged vertically opposite each other at a predetermined interval. On the other hand, a plurality of disk-shaped substrates are stacked with their centers located on one axis (X-axis) to form a substantially cylindrical body, and the substantially cylindrical body is stacked with the center thereof positioned on one axis (X-axis). At the same time, the axis passing through the one axis (X axis) and extending between the targets is set as the other axis (Y axis), and the target is rotated around the other axis (Y axis), and . A method for manufacturing a magnetic disk for a rotary encoder, characterized in that sputtering deposition is performed while eccentrically rotating the other axis (Y-axis).