JPS6212923A - Method for manufacturing magnetic recording media - Google Patents

Abstract

PURPOSE:To easily form a thin continuous magnetic film having good magnetic characteristics by surely depositing a sputter material from a target surface onto a disk substrate from a diagonal direction and executing a reactive sputtering method as well as reduction and oxidation heat treatments, etc. CONSTITUTION:A pair of target cathodes 2, 3 essentially consisting of Fe are disposed to face each other in parallel via a prescribed space 6 in a vacuum vessel 1 of a reaction sputtering device to be applied in the stage of forming an alpha-Fe2O3 film onto the substrate 7 by reactive sputtering using the target cathodes essentially consisting of Fe. A rotary supporting plate 4 attached with the substrate 7 is disposed in the direction orthogonal with the target 2 surface on the side nearer at least one target cathode 2 side than the middle of the space 6 where a pair of the cathodes 2 and 3 face each other. Sloped multi-stage slits 8 are further disposed between a pair of the cathodes 2, 3 and the substrate 7. The sputtering gaseous atmosphere adjusted to a suitable gaseous pressure within a 1-5mu10<-2>Torr range is maintained in the vessel 1 and the reactive sputtering is executed.

Description

[Detailed Description of the Invention] [Summary] A pair of target cathodes containing Fe as a main component are disposed in parallel to each other with a predetermined space in between in a vacuum container, and a disk substrate is placed on the side of at least one of the target cathodes. A rotary support plate with a rotary support plate attached thereto is arranged in a direction perpendicular to the target surface, and an inclined multi-stage slit is arranged between the pair of target cathodes and the disk substrate, and the inside of the vacuum vessel is heated in the range of 1 to 5 x 10-2 Torr. Reactive sputtering is performed in an Ar 02 sputtering atmosphere under gas pressure, and a sputtering Fe oxide is deposited obliquely on a rotating disk substrate through an inclined multi-stage slit.
2. Forming an O3 film, and then subjecting the α-Fe2O3 film to reduction and oxidation heat treatment to easily form a γ-Fe2O3 magnetic film having uniform magnetic anisotropy with the axis of easy magnetization in the circumferential direction of the substrate. Therefore, it is possible to obtain a magnetic recording medium suitable for high-density recording and reproduction.

[Industrial application field]

The present invention relates to a method of manufacturing a magnetic recording medium used in a magnetic disk device, etc., and particularly a magnetic recording medium having magnetic anisotropy with an axis of easy magnetization in a recording direction (circumferential direction of a substrate) that is advantageous for high-density recording. The present invention relates to a manufacturing method.

The conditions required for high-density recording of magnetic recording media used in magnetic disk drives, etc. are high coercive force, good squareness of the magnetization curve, and magnetic anisotropy with the recording direction as the axis of easy magnetization. It is necessary to use a large magnetic thin film and to reduce the flying distance between the recording medium and the recording head.

Conventionally, magnetic recording media used in magnetic disk devices, magnetic tape devices, etc. are made by applying γ-Fe2O3 magnetic powder dispersed in a binder to the surface of a disk substrate.
It is known that the magnetic powder is oriented so that the recording direction is the axis of easy magnetization, thereby imparting magnetic anisotropy. Although such magnetic recording media are extremely effective in increasing the output, resolution, and S/N of recording/reproduction signals,
It was difficult to reduce the film thickness to 1 μm or less.

To solve this problem, Patent No. 102 discloses a manufacturing method for forming a continuous magnetic thin film using sputtering, which is easy to thin the film.
4363 (Japanese Patent Publication No. 55-14522) etc., the magnetic properties of the magnetic film formed by this manufacturing method are isodirectional within the film plane, and the magnetic property is that the recording direction is the axis of easy magnetization. It is difficult to form a magnetic thin film having anisotropy, and there is a need for a method that can easily form a magnetic thin film having the above-mentioned magnetic anisotropy.

[Conventional technology]

Therefore, in order to solve the above problem, as previously proposed by the present inventors in JP-A-59-181524, a disk substrate with different surface roughness in two orthogonal directions within the substrate surface was used. An oxide mainly composed of Fe is obliquely deposited on the surface of the disk substrate by reactive sputtering or the like to form an α-Fe2O3 film, and the α-Fe2O3 film is subjected to reduction and oxidation heat treatment. This makes it possible to form a continuous magnetic thin film of γ-Fe2O3 having uniaxial magnetic anisotropy on a substrate.

[Problem that the invention seeks to solve]

However, in such a method, it is necessary to process the substrate surface into a rough surface with directionality in advance, which further complicates this process, and also increases the magnetic anisotropy with the recording direction of the medium as the axis of easy magnetization. It has not been easy to obtain a continuous magnetic thin film having such magnetic properties with good reproducibility.

In view of these conventional circumstances, the present invention has a structure in which the sputtered material from the target surface is reliably deposited obliquely on the disk substrate to which the magnetic thin film is to be deposited, and the gas in the reactive sputtering atmosphere is By using a reactive sputtering method using sputtering conditions with an appropriately set pressure and heat treatment for reduction and oxidation, magnetic anisotropy with the recording direction of the medium as the axis of easy magnetization can be achieved without any pretreatment such as surface roughening of the disk substrate. The object of the present invention is to provide a manufacturing method that can easily form a continuous magnetic thin film with good magnetic properties.

[Means for solving problems]

In order to achieve the above object, the present invention uses a reactivity applied when forming an α-Fe2O3 film on a substrate 7 by reactive sputtering using a target cathode mainly composed of Fe, as shown in FIG. In a vacuum chamber 1 of a sputtering apparatus, a pair of target cathodes 2 and 3 containing RE as a main component are arranged parallel to each other with a predetermined space 6 in between. Disposed in a direction perpendicular to the surface of the target 2 at the side of at least one of the two target cathodes from the middle of the opposing space 6 of the target cathodes 2.3, and further between the pair of target cathodes 2.3 and the substrate 7. It has a configuration in which inclined multi-stage slits 8 are arranged.

Then, the vacuum container 1 in this state is filled with a mixed gas made by mixing the gauge gas and the 02 gas at a volume ratio of 1:1.
Reactive sputtering is performed in a sputtering gas atmosphere with an appropriate gas pressure in the range of ~5×l0-2 Torr, and an α-Fe2O3 film is formed on the rotating substrate 7 through the inclined multi-stage slit 8. -The Fe2O3 film is further subjected to reduction and oxidation heat treatment to form a γFe2O3 magnetic film [Function] As described above, in the manufacturing method of the present invention, 1 to 5X10-2T
In an Ar-0° mixed gas atmosphere adjusted to an appropriate gas pressure within the range of orr, sputtered Fe oxide was deposited obliquely on the rotating substrate 7 through the inclined multistage slit 8 by reactive sputtering. By forming an α-Fe2O3 film and further subjecting the α-Fe2O3 film to reduction and oxidation heat treatment, the ratio of the residual magnetism Brl in the circumferential direction and the residual magnetism Br2 in the radial direction in the B-H curve is 1.0.
With the above, it is possible to easily form a continuous magnetic thin film made of γ-Fe2O3 with good magnetic properties and uniform magnetic anisotropy with the recording direction of the medium (circumferential direction of the substrate) as the axis of easy magnetization. It becomes possible.

〔Example〕

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

FIG. 1 is a configuration diagram showing an embodiment of a reactive sputtering apparatus that is applicable to the method of manufacturing a magnetic recording medium according to the present invention.

To explain the manufacturing method of the present invention with reference to this configuration diagram, first, a pair of water-cooled target cathodes 2.3 containing Fe as a main component are arranged in parallel and facing each other in a vacuum container 1 with a predetermined space 6 in between.

Next, the rotating support plate 4 on which the non-magnetic disk substrate 7 on which the magnetic film is to be formed is attached to the pair of target cathodes 2 and 3.
At least one target cathode is disposed in the middle of the opposing space 6, for example, as shown, on the side of the downward-facing target cathode 2 in a direction perpendicular to the surface of the target cathode 2, and furthermore, the pair of target cathodes 2. 3 and the board 7,
It has a configuration in which inclined multi-stage slits 8 are installed on a water-cooled base 9. In this case, the inclination angle of the inclined multi-stage slit 8 is 60 degrees from the surface of the target cathode 3. Further, the rotation support plate 4 is connected to the rotation mechanism section 5.

Next, the inside of the vacuum container 1 in this state is once evacuated to a high vacuum using a vacuum evacuation device (not shown), and then filled with a mixed gas of Ar gas and 02 gas mixed at a volume ratio of 1:1. Sputtering is performed in a sputtering gas atmosphere with an appropriate gas pressure in the range of ~5 X 10' Torr, for example, 2 X 10-2 Torr, and the sputtering is performed diagonally through the inclined multistage slit 8 onto the rotating disk substrate 7. Sputtered Fe oxide was deposited from the direction of α-F.
Form an e2O3 film.

Thereafter, the α-Fe2OJ* is further treated according to a conventional reduction and oxidation heat treatment process, so that a magnetic field is uniformly imparted with magnetic anisotropy with the easy axis of magnetization in the circumferential direction of the substrate 40 (recording direction of the medium). It becomes possible to easily form a continuous magnetic thin film made of γ-Fe2O3 with good characteristics.

Incidentally, a pair of target cathodes 2,
3 and the rotary support plate 4 to which the disk substrate 7 is attached, for example, the opposing space 6 between the pair of target cathodes 2.3, that is, the opposing distance is 110 mm, and one target cathode 2. The rotating support plate 4 to which the disk substrate 7 (for example, diameter: 130 mm) is attached is placed such that the center of its rotational axis is 30 mm from the surface of the target cathode 2.
It is set n+m behind, and is disposed so as to face the outer circumferential end surface of the target cathode 2 with a distance of 100 mm%lt in the lateral direction from the outer circumferential edge end of the target cathode 2 .

Furthermore, the pair of target cathodes 2 and 3 and the disk substrate 7
4゜1III11 installed on water-cooled base 9 between
An inclined multi-stage slit 8 is disposed with a thickness of .about.60 degrees and an angle of inclination of 60 degrees from the surface of the target cathode 3.

Next, Ar gas and 02 gas are mixed at a volume ratio of 1:1,
Sputtering is performed in a sputtering gas atmosphere with a gas pressure of 2 x 10-2 Torr, and sputtered Fe oxide is deposited obliquely on the rotating disk substrate 7 through an inclined multi-stage slit 8.
A 2O3 film is formed, and the a-Fe2Oall! ' is treated according to conventional reduction and oxidation heat treatment steps to obtain γ-F
A continuous magnetic thin film made of e2O3 is formed.

Such a continuous magnetic thin film is subjected to a VSM device (Vibrating
As a result of measuring the magnetic properties using a sample magnetometer, it was found that there was a bend B on the entire surface of the continuous magnetic thin film.
The value of the ratio between the residual magnetism Brl in the circumferential direction and the residual magnetism Br2 in the radial direction in the -H curve (the value of this ratio is 1.
(The larger the value is than 0, the greater the magnetic anisotropy with the recording direction of the medium as the axis of easy magnetization) is 1.26, which means that the recording direction of the medium (circumferential direction of the substrate 7) is the axis of easy magnetization. We were able to provide uniform and strong magnetic anisotropy. Therefore, it is possible to obtain a magnetic recording medium with extremely good magnetic properties and improved high-density recording and reproduction with good reproducibility.

FIG. 2 is a configuration diagram showing a reactive sputtering apparatus that can be used in another embodiment of the method for manufacturing a magnetic recording medium according to the present invention. Parts equivalent to those in FIG. 1 are given the same symbols.

The embodiment shown in FIG. 2 differs from the example shown in FIG. 1 in that there are four rotary support plates 4a to which disk substrates 7 are attached.

4b, 4c and 4d are respectively arranged on both sides of the pair of target cathodes 2.3 arranged oppositely based on the arrangement positional relationship shown in FIG. Each rotation support plate 4a+4b+4
A water cooling base 21 is placed between the disk substrates 7 on c and 4d.
．． Ar gas and 02 gas are mixed at 1:1 with a configuration in which slanted multi-stage slits 24 and 25 are installed on 22, respectively.
Mix at a volume ratio of 1, and increase the gas pressure of this mixed gas to 2
Sputtering is performed in a sputtering gas atmosphere of 10' Torr, and each rotating mechanism 5a.

a rotating support plate 4a rotated by 5b, 5c and 5d;
Sputtered Fe oxide is obliquely deposited on the surface of each disk substrate 7 on 4b, 4c, and 4d through the slanted multi-stage slits 24, 25 to form an α-Fe2O3 film.

Thereafter, the α-Fe2O3 film was heat treated according to conventional reduction and oxidation heat treatment steps to form a continuous magnetic thin film made of γ-Fe2O3. In this embodiment, by using the inclined multi-stage slit 7) 24, 25, the deposition rate of the α-Fe2O3 film deposited on each disk substrate 7 surface is reduced, but as described above, four disk substrates 7 can be formed at the same time. It becomes possible to form a continuous magnetic thin film with good reproducibility on which magnetic anisotropy is imparted with the axis of easy magnetization in the circumferential direction of the substrate, which has the advantage of improving productivity.

〔Effect of the invention〕

As is clear from the above description, according to the method for manufacturing a magnetic recording medium according to the present invention, magnetic anisotropy with the easy magnetization axis in the circumferential direction can be uniformly imparted to the disk substrate easily and reliably. Continuous magnetic thin films made of metal oxides can be easily fabricated.
It also has the excellent advantage of being able to be formed with good reproducibility, making it possible to provide a magnetic recording medium suitable for high-density recording and reproduction.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a reactive sputtering apparatus applied to the method of manufacturing a magnetic recording medium according to the present invention, and FIG. - It is a block diagram which shows another Example of 7 Kling apparatus. In Figures 1 and 2, 1 is a vacuum vessel, 2.3 is a target cathode, and 4.4a to 4
d is a rotating support plate, 6 is an opposing space, 7 is a disk substrate, 8
．． 24 and 25 indicate multistage slits, respectively. 1J enemy9. Ban o curse (Akebono II%' direction is used for Ij hfi no Mizo Bokou 7u ticket) f4! :Moe 4 Ihi, I hate σ±. November 14, 1985 Relation to Patent Application No. 153041 of 1985 Patent Applicant Address 1015 Kamiodanaka, Nakahara-ku, Yozaki City, Kanagawa Prefecture (5
22) Name Fujitsu Ltd. 5, 7ili Date of official order None Claims (Amend the "Claims" of the 11th specification as shown in the attached sheet. (2) Page 2, line 9 of the specification - Line 10, page 6, line 19, page 7, lines 7 to 8, and page 9, line 6 “1 to 5”
X 10-2 TorrJ r 1~5 X 10-3T
Correct to orrJ. (3) Page 9, line 7, page 10, line 15 and 1 of the specification
r 2 X 10' TorrJ on page 2, line 8
Correct to X 10-3TorrJ. 8. List of attached documents Claims 1 or more copies A pair of target cathodes (2, 3) containing Fe as a main component are disposed in parallel and facing each other with a predetermined space interposed therebetween in a vacuum container (1), and at least one A rotary support plate (4) with a disk substrate (7) attached is placed on the side of the target cathode (2).
) are arranged in a direction perpendicular to the target surface, and the pair of target cathodes (2°3) and the disk substrate (
An inclined multi-stage slit (8) is arranged between the vacuum container (1) and the sputtering atmosphere gas pressure in the range of 1 to 5 x 10'Torr to perform reactive sputtering and rotate. α-Fe on the disk substrate (7)
2O3 film is formed, and then the α-Fe2O3 film is subjected to reduction and oxidation heat treatment to form a γ-Fe2O3 magnetic film having anisotropy with the axis of easy magnetization in the circumferential direction of the substrate (7). A method for manufacturing a magnetic recording medium.

Claims (1)

[Claims] A pair of target cathodes (2, 3) containing Fe as a main component are disposed in a vacuum container (1) in parallel to each other with a predetermined space in between, and a disk is placed on the side of at least one of the target cathodes (2). Rotating support plate (4) with board (7) attached
) are arranged in a direction perpendicular to the target surface, and the pair of target cathodes (2, 3) and the disk substrate (
7), and perform reactive sputtering by placing an inclined multi-stage slit (8) between the vacuum container (1) and creating a sputtering atmosphere gas pressure in the range of 1 to 5 x 10^-^2 Torr; α on the rotating disk substrate (7)
-Fe_2O_3 film is formed, and then the α-Fe_2
The O_3 film is subjected to reduction and oxidation heat treatment to produce γ-Fe_2O_, which has anisotropy with the easy magnetization axis in the circumferential direction of the substrate (7).
3. A method for manufacturing a magnetic recording medium, characterized by forming a magnetic film.