JPS62120632A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having good durability by forming the medium in such a manner that two sputtering sources exist within the virtual plane when at least one virtual plane parallel with the conveying direction of the substrate and perpendicular to a sputtering target platen is considered and that specific conditions are satisfied in said plane. CONSTITUTION:A Co-Cr magnetic recording layer 7 is formed by disposing the flexible conveying substrate 3 and and Co-Cr target 1 in such a manner that the two sputtering sources 5, 6 exist within the virtual plane parallel with the conveying direction of the substrate 3 and perpendicular to the target 1 plane. Two masks 8, 9 are provided between the Co-Cr target 1 and the substrate 3. The point O where the formation of the magnetic layer by the mask 8 is started corresponds to the surface of the substrate 3 right under the end of the substrate 3. The mask 8 is so installed as to attain theta2>theta1 when the angle between the normal OO' to the surface of the substrate 3 at the point O and the line OA connecting the point O and the central point A of the sputtering source 5 is theta1 and the angle between the normal OO' and the line OB connecting the point O and the central point B of the sputtering source 6 is designated as theta2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to the production of magnetic recording media in which a recording magnetic layer is continuously formed on a substrate being transported by magnetron sputtering.

[Technical background of the invention and its problems]

In recent years, with the development of information processing technology, the amount of information carried by memory devices has increased dramatically, and the demand for larger capacities for magnetic recording media such as floppy disks has also increased. In order to meet this demand, research and development has been actively conducted on magnetic recording media capable of high-density recording, particularly magnetic recording media for perpendicular magnetic recording that performs recording using magnetization perpendicular to the film surface. ing. A magnetic recording medium for perpendicular magnetic recording is a medium equipped with a recording magnetic layer that has perpendicular magnetic anisotropy, and is different from the coated media that constitutes most of the magnetic recording media for in-plane recording currently in practical use. Also, a metal thin film type medium in which a thin metal film such as a Co-Cr alloy is formed as a recording magnetic layer by sputtering or vapor deposition, or an oxide thin film type medium having a magnetoplumbite crystal structure such as Ba ferrite or Sr ferrite is used. It is seen as a promising medium suitable for high-density recording.

By the way, in coated media, the recording magnetic layer is formed by mixing magnetic powder with a binder etc. and coating it on the substrate, so the recording magnetic layer has elasticity, and it is also possible to mix a lubricant into the magnetic layer. It is also possible to maintain good contact between the medium and the magnetic head, thereby ensuring sufficient durability of the medium and the head.

On the other hand, in metal thin film media and oxide thin film media, the recording magnetic layer has almost no elasticity, so when a magnetic head made of hard material such as ferrite runs over the media, the media surface and head Damage such as scratches is likely to occur on the surface. In that case, not only will the durability of the media and head be impaired, but the effective distance between the media and the head will increase due to the adhesion of abrasion particles on the media and head, resulting in an increase in spacing and loss per frequency. This can cause deterioration of characteristics, decrease in output during playback, and output fluctuation.

[Purpose of the invention]

An object of the present invention is to provide a method for manufacturing a magnetic recording medium that has good durability even when a metal thin film is used as the recording magnetic layer.

[Summary of the invention]

A method for producing a magnetic recording medium according to the present invention includes a method for continuously forming a recording magnetic layer on a substrate being transported by magnetron sputtering, in which at least one magnetic recording layer is formed parallel to the substrate transport direction and perpendicular to the sputter target surface. When a virtual plane is considered, two sputter sources exist within that plane, and the following conditions are satisfied within that plane.

That is, a line OA connecting the magnetic layer formation start point on the substrate (hereinafter referred to as point 0) and the center point of the first sputtering source located on the upstream side in the roll conveyance direction (hereinafter referred to as point A); The angle formed by the modulus @■' with respect to the substrate surface at point 0 is θ1, and the angle formed by line OB and line OO' connecting point 0 and the center point of the second sputtering source (hereinafter referred to as point B) is 02. When θ2mel.

In addition, the target is a ferromagnetic target whose main components are Co and Cr, and the recording magnetic layer is Co-Cr.
It is characterized by being a series alloy. Furthermore, the recording magnetic layer is characterized by having perpendicular magnetic anisotropy.

〔Effect of the invention〕

According to the printing method of the present invention, a magnetic recording medium having good durability can be manufactured.

In particular, in Co-Cr alloy thin film media, which have perpendicular magnetic anisotropy and are most suitable for high-density recording as perpendicular magnetic recording media, thin film The intensity of changes. Therefore, by controlling the viewing angle of the two sputtering sources at the starting point of forming the magnetic layer as described above, a magnetic recording medium with good durability can be manufactured.

[Embodiments of the invention]

An embodiment of the method for manufacturing a magnetic recording medium of the present invention will be described below with reference to the drawings. In magnetron sputtering, a magnet is placed on the back side of the target, and as a result of this arrangement, an erosion area 2 in the shape of a racetrack track, a circle, a rounded circle, or any other shape is formed on the narrow side of the target 1, as shown in FIG. It is formed by continuing sputtering. That is, the sputtered atoms do not fly out from the entire surface of the target, but from a specific region 2.

At this time, as shown in FIG. 3, when considering at least one virtual plane 4 parallel to the conveying direction of the substrate 3 and perpendicular to the target surface, two sputter sources 5.6 exist within that plane. Become.

Therefore, as shown in FIG.
r target 1 in the above relationship, that is, the two sputtering sources 5.6 are arranged in a virtual plane parallel to the transport direction of the substrate 3 and perpendicular to the surface of the target 1, and the Co-C
r to form the recording magnetic layer 7, and Co
- two VC masks 8 between the Cr target 1 and the substrate 3;
9 will be provided.

The masks 8 and 9 are provided in the following positional relationship.

That is, using the mask 8, the recording magnetic layer formation starting point 0 is
This corresponds to the surface of the base 3 directly below the edge of the mask 8 . Therefore, the angle formed by the normal OO' to the surface of the substrate 30 at the point O and the line OA connecting the point O and the center point A of the sputtering source 5 is θl, and similarly.

When the angle between the normal 00' and the line OB connecting the point 0 and the center point B of the sputtering source 6 is 02, the mask 8 is installed so that θ2>θl.

That is, in the present invention, when forming a recording magnetic layer using two sputtering sources, the recording magnetic layer formation starting point is distanced from the sputtering source located upstream of the sputtering source located downstream in the conveyance direction of the substrate. Perform sputtering by arranging it so that it is close to .

The Co--Cr thin film medium thus formed has a high frequency of magnetic layers and is difficult to break. Therefore, extremely high durability can be obtained even in the case of a floppy disk in which the magnetic head runs in continuous contact with the medium.

Table 1 shows the results of experiments in which the durability of media formed by variously changing the position of the mask 3 and changing the values of θ1 and 02 was investigated. This medium was coated on both sides of a heat-resistant flexible film with a thickness of 75 μm by changing the position of the mask 8 in various ways using the apparatus shown in FIG.
After forming the r-alloy thin film, it was punched out into a disk shape with a diameter of 3.5 inches to form a floppy disk.

The experiment was conducted with a ferrite magnetic head in contact with the same track on the disk while rotating the medium at a speed of 3001'' per minute (pm).

Number of trips (buses) before the media is significantly damaged. This refers to a state in which a portion of the co-Cr alloy thin film 5 is severely damaged and the surface of the base 2 is exposed.

Furthermore, an extremely small amount of liquid lubricant was directly applied to the surface of the Co-Cr recording layer using a spin code method.
Lubrication conditions were the same for all samples.

Table 1 (L1 Human Life 6Q wc1) As is clear from the table below, for the medium in which the mask 3 is arranged so as to satisfy the condition θ2>θl.

All showed good durability of 1 million passes or more.

Table 1 also shows, as comparative examples, media created by arranging the mask 3 to satisfy θ2≦01, but all of these have durability of 1 million passes or less, which is not practical. The results were satisfactory.

In addition, similar experiments were conducted for cases other than those shown in Table 1 that satisfied the condition θ2≦θ1, but none showed durability of 1 million passes or more.

Although there is some variation in these results, θ2>
It can be said that there is a clear difference in durability between the case where the condition θ1 is satisfied and the case where the condition θ2≦01 is satisfied.

In addition, as shown in Table 1, if the difference between 02 and 01 becomes too large, durability will deteriorate, so θ2 and 0
1 is preferably about 50' or less.

Further, when considering not only the durability but also the crystal orientation of the recording magnetic layer, it is preferable that the difference between θ2 and 01 is about 20° or less.

[Other embodiments of the invention]

FIG. 4 shows another embodiment of the invention. roll 24
When considering a plane perpendicular to the axis of and perpendicular to the Co-Cr target 21, the Co-Cr target 2 on the plane
10 surface, there are two sputter sources 22, 23,
Roll 241'l: A Co--Cr recording magnetic layer 26 is formed on a film-like substrate 25 that can be conveyed while being in contact with it. Between the roll 24 and the target 21 there are two masks 27.2.
8 are provided to selectively deposit sputtered atoms onto the substrate 25. The roll 24 and the substrate 25 are rotated clockwise, and the Co--Cr magnetic layer is attached to the substrate 2 at the end point P of the mask 27.
5 begins to form.

Substrate 25 at magnetic layer formation starting points P. Let θ3 be the angle between the normal line PP' to the surface of The mask 27 is installed so that θ3 minus θ4 is established when the angle formed with the line PD connecting is 04.

The Co--Cr thin film medium formed in this manner also has excellent durability similar to the magnetic recording medium manufacturing apparatus described in the above embodiment.

This invention is not limited to the embodiments described above,
Various modifications can be made without departing from the gist of the invention.

For example, the recording magnetic layer may be a Co-Cr based alloy thin film containing components other than Co and Cr, such as a Co-Cr-Rh alloy thin film, and the target may also be a Co-Cr based alloy thin film containing components other than Co and Cr.
7. May contain the following ingredients.

Furthermore, various materials and shapes of the base can be selected. In the examples, the case where a flexible substrate is used has been described, but the present invention can also be applied to the case where a magnetic layer is formed on a non-flexible substrate such as an anodized aluminum plate while being transported. Of course.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining a method of manufacturing a magnetic recording medium according to an embodiment of the present invention, FIG. 2 is a diagram showing an erosion area of a target, and FIG. 3 is a diagram of a virtual plane in the embodiment of FIG. The conceptual diagram, FIG. 4, is a diagram showing another embodiment of the present invention. 1, 21 - Co-Cr target, 2 - two lotion regions, 3 - flexible substrate, 4 - virtual virtual plane, 5.6 - sputtering source on virtual virtual plane 4, 7, 26 - Co-Cr thin film magnetism layer, 8, 9, 27, 28 - mask, 22. 23 - sputtered layer, 24 - roll, 25 - film-covered substrate. Agent Patent Attorney Noriyuki Chika Yudo Kikuo Takehana IO' Figure 2

Claims (4)

[Claims] (1) In a method for manufacturing a magnetic recording medium, in which a recording magnetic layer consisting of a continuous film is formed on a substrate by magnetron sputtering while the substrate is being conveyed, the magnetic recording layer is parallel to the conveying direction of the substrate and perpendicular to the target surface. First and second sputtering sources exist in at least one virtual plane, and in the plane, the first sputtering source is located upstream of the magnetic layer formation start point on the substrate and the moving direction of the substrate. The angle between the line connecting the centers of the sputtering sources and the normal to the substrate surface at the starting point of forming the magnetic layer is θ_
1 and the angle between the normal line and a line connecting the magnetic layer formation start point and the center of the second sputtering source downstream in the direction of movement of the substrate is θ_2, then θ_2>θ_1 1. A method for manufacturing a magnetic recording medium, characterized in that a recording magnetic layer is formed so as to satisfy the following relationship. (2) The method for manufacturing a magnetic recording medium according to claim 1, wherein the target is a ferromagnetic target containing Co and Cr as main components. (3) The method for manufacturing a magnetic recording medium according to claim 1, wherein the recording magnetic layer is a Co-Cr alloy thin film. (4) The method for manufacturing a magnetic recording medium according to claim 1, wherein the recording magnetic layer has perpendicular magnetic anisotropy.