JPH09202964A - Vacuum deposition apparatus and method of manufacturing magnetic recording medium using the same - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a vacuum vapor deposition apparatus capable of forming a high-quality metal film with excellent productivity regardless of the oxygen content.
Further, there is provided a method for manufacturing a high-quality magnetic recording medium at low cost by using this vacuum vapor deposition device. In a vacuum vapor deposition apparatus, the inside of a crucible 8 is provided with a material supply region 21 where a metallic material is replenished and a main melting region 22 where an electron beam is irradiated in the vicinity of a liquid surface of a molten liquid of the metallic material. The storage portion 2 is partitioned and provided in the material supply region 21 so that the molten liquid near the liquid surface in this region can flow into the material supply region 21.
5 is connected. Then, by using this vacuum vapor deposition device, the material supply region 21 contains Co as a main component and oxygen of 50 to 50 as a main component.
A metal magnetic thin film is formed while replenishing the metal magnetic material containing 00 ppm to suppress the inflow of suspended solids into the main melting region 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called vacuum vapor deposition apparatus, and to a method for manufacturing a magnetic recording medium in which a metal magnetic thin film is formed using this vacuum vapor deposition apparatus.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, a powdery magnetic material such as an oxide magnetic powder or an alloy magnetic powder has been coated on a nonmagnetic support by a vinyl chloride-vinyl acetate copolymer,
A coating type magnetic recording medium prepared by coating and drying a magnetic coating material dispersed in an organic binder such as polyester resin, urethane resin or polyurethane resin is widely used.

On the other hand, with the growing demand for high-density magnetic recording, Co-Ni alloys, Co-Cr alloys,
-O or the like, a metal magnetic material is subjected to plating or vacuum thin film forming means (vacuum vapor deposition method, sputtering method, ion plating method, etc.) to form a polyester film or polyamide,
A so-called metal magnetic thin film type magnetic recording medium directly attached on a non-magnetic support such as a polyimide film has been proposed and attracted attention.

This metal magnetic thin film type magnetic recording medium is excellent not only in coercive force and squareness ratio but also in electromagnetic conversion characteristics at short wavelengths, and the magnetic layer can be made extremely thin, so that recording demagnetization and reproduction are possible. The thickness loss at the time is extremely small,
Since there is no need to mix a binder, which is a non-magnetic material, in the magnetic layer, there are various advantages such that the packing density of the magnetic material can be increased.

Further, in order to improve the electromagnetic conversion characteristics of this kind of magnetic recording medium and obtain a larger output, when forming the magnetic layer of the magnetic recording medium, the magnetic layer is obliquely formed. So-called oblique vapor deposition for vapor deposition has been proposed and put to practical use. In order to obliquely deposit the magnetic layer, an ingot of a magnetic metal material is placed in the crucible, and this is vaporized by irradiating it with an electron beam from an electron gun,
It is a general practice to adhere the vapor to a continuously running non-magnetic support while controlling the incident angle of the vapor with a shutter or a mask.

When vapor deposition is continuously performed, pellets of the magnetic metal material may be sequentially replenished as the metal magnetic material in the crucible is consumed.

[0007]

By the way, in the metallic magnetic material used for the above-mentioned vapor deposition, Ni, F
The content of metal elements such as e, Cr, and Cu has a great influence on the magnetic characteristics of the magnetic layer, and therefore must be strictly controlled.

Further, the contents of gas components such as O ₂ , C and N are required to be kept as low as possible. If the metallic magnetic material contains a gas component, bumping (splash) will occur during melting, and these droplets will reach the non-magnetic support, causing minute heat loss in the magnetic layer, resulting in a bad hit or drop. This is because it causes out. Furthermore, when a metal magnetic material having a high O ₂ content is used, the surface of the melt is covered with suspended matter made of an oxide, which also lowers the film formation rate. In order to obtain a predetermined film forming rate, it is necessary to increase the power of the electron beam to be irradiated, which leads to lack of stability of the electron beam and shortening of the life of the electron gun.

However, in the commercially available metallic magnetic materials, even if the content of the metal element is suppressed so that the influence on the magnetic properties can be ignored, the content of the gas component is sufficiently reduced. Not not. For this reason, refining processing is required in advance when using a high-quality metal magnetic material having a low gas component content during vapor deposition. That is, if an attempt is made to prepare a metallic magnetic material having a low gas component content, the cost will inevitably increase.

Therefore, in view of the conventional circumstances, the present invention provides a vacuum vapor deposition apparatus capable of forming a high quality metal film with excellent productivity regardless of the content of gas components, particularly oxygen. It is also an object of the present invention to provide a method for manufacturing a high-quality magnetic recording medium at low cost by using this vacuum vapor deposition device.

[0011]

A vacuum vapor deposition apparatus according to the present invention achieves the above-mentioned object, and is provided in a film forming chamber,
In a vacuum vapor deposition apparatus having at least a cylindrical can for traveling a support, a crucible arranged below the cylindrical can, and an electron beam irradiation means for irradiating a metal material filled in the crucible with an electron beam. , The inside of the crucible, in the vicinity of the liquid surface of the melt of the metal material, is partitioned into a material supply region where the metal material is replenished and a main melting region where the electron beam is irradiated, and in the material supply region, The reservoir is provided so that the molten liquid in the vicinity of the liquid surface in this region can flow in.

In the crucible of this vacuum vapor deposition apparatus, since the material supply region and the main melting region are partitioned near the liquid surface of the molten liquid, the metal material replenished in the material supply region is melted, and this molten liquid is melted. Even if there are suspended solids, the suspended solids do not flow into the main melting area. Therefore, in the main melting region,
The surface of the melt of the metal material is not covered with the suspended matter, and vaporization can be stably performed. Further, if this crucible is used, the metal material is prevented from moving from the material supply region to the main melting region in a solid state, and therefore this does not cause a splash. The crucible used here is formed to be longer than the width of the cylindrical can.
It is premised that the main melting region is arranged so as to face the peripheral surface of the cylindrical can and the material supply region is arranged so as not to face the peripheral surface of the cylindrical can.

Further, in this crucible, since the material supply region is connected to the storage portion provided so that the molten liquid near the liquid surface in this region can flow in, the molten liquid floats in the storage portion. The suspended solids can be discharged.

The method of manufacturing a magnetic recording medium according to the present invention comprises:
The non-magnetic support is continuously run in the film forming chamber of the vacuum evaporation system, and the metallic magnetic material in the crucible is heated and evaporated by irradiation of an electron beam to form a metallic magnetic thin film on one main surface of the non-magnetic support. When filming, the inside of the crucible,
In the vicinity of the liquid surface of the molten liquid of the metal magnetic material, the material supply region where the metal magnetic material is replenished and the main melting region where the electron beam is irradiated are partitioned, and during the film formation, in the material supply region,
The main component is Co, and the metallic magnetic material containing 50 to 5000 ppm of oxygen is replenished.

As described above, by partitioning the material supply region and the main melting region in the vicinity of the liquid surface of the melt, it is not necessary for the suspended liquid of the melt in the material supply region to flow into the main melting region. In the melting region, vaporization of the magnetic metal material can be performed stably. It is also possible to suppress splash.
Therefore, even if a metal magnetic material containing oxygen is used, a magnetic layer with few dropouts can be formed without increasing the power of the electron beam, and a high-quality magnetic recording medium can be manufactured at low cost. It becomes possible to do.

Further, if a storage portion provided so that the melt near the liquid surface in this region can flow is connected to the material supply region, the metallic magnetism is generated while the suspended matter floating in the melt is discharged. A thin film can be formed.

As a metallic magnetic material, oxygen is 50 to 500 p
In the case of using the material containing pm, a magnetic layer with a small dropout can be formed only by using the crucible described above, and even in the case of using the material containing oxygen of 500 to 5000 ppm, Al or Ti as a reducing agent is added to the material supply region. By supplying at least one of them, a magnetic layer with less dropout can be obtained. It should be noted that a metal magnetic material having an oxygen content of less than 50 ppm is not practical because the cost is high, and the oxygen content is 5000 pp.
With respect to the metallic magnetic material exceeding m, even if the crucible having the above-mentioned configuration is used or the reducing agent such as Al or Ti is supplied, the suspended matter flows into the main melting region.
When a metal magnetic material containing oxygen of 500 to 5000 ppm is used, Al and Ti supplied as a reducing agent are 50
It is preferably set to 500 ppm. If it is too small, the effect as a reducing agent does not sufficiently appear, and if it is too large, the magnetic properties of the metal magnetic thin film are affected.

On the other hand, as the metal magnetic material to be filled in the crucible in advance before forming the metal magnetic thin film, it is preferable to use a metal magnetic material having an oxygen content of 500 ppm or less. If an oxygen content higher than this is used, a large amount of suspended matter floats in the melt, causing dropout or deterioration of the film forming rate.

[0019]

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

An example of a vacuum vapor deposition apparatus to which the present invention is applied is shown in FIG. In this vacuum vapor deposition apparatus, a film forming chamber 1 whose inside can be depressurized by being exhausted from an exhaust port (not shown)
A feed roll 3 that rotates at a constant speed in the direction a in the figure and a winding roll 4 that rotates at a constant speed in the direction b in the figure are provided therein. From the feed roll 3 to the winding roll 4, a tape-shaped nonmagnetic material is provided. The support 2 is designed to travel sequentially.

A cylindrical can 5 having a diameter larger than that of each of the rolls 3 and 4 is provided in the middle of the non-magnetic support 2 running from the feed roll 3 toward the winding roll 4. There is. The cylindrical can 5 is provided so as to pull out the non-magnetic support 2 laterally in the drawing, and is configured to rotate at a constant speed in the direction c in the drawing.

The feed roll 3, the winding roll 4 and the cylindrical can 5 each have a cylindrical shape having a length substantially the same as the width of the non-magnetic support 2. Further, the cylindrical can 5 is provided with a cooling device (not shown) inside so as to suppress deformation and the like of the non-magnetic support 2 due to a temperature rise.

Therefore, the film forming chamber 1 of this vacuum vapor deposition apparatus
In the inside, the non-magnetic support 2 is sequentially fed out from the feed roll 3, further passes through the peripheral surface of the cylindrical can 5, and is wound up by the winding roll 4.

A crucible 8 is provided below the cylindrical can 5 in the film forming chamber 1, and a metal magnetic material 9 is filled in the crucible 8. Further, pellets are supplied to the crucible 8 from a pellet supply means (not shown).

On the other hand, an electron gun 10 for heating and evaporating the metallic magnetic material 9 filled in the crucible 8 is attached to the upper wall of the film forming chamber 1. The electron gun 10 is arranged so that the electron beam X emitted from the electron gun 10 irradiates the metallic magnetic material 9 in the crucible 8. Then, the nonmagnetic support 2 in which the metallic magnetic material 9 evaporated by the electron gun 10 runs at a constant speed on the peripheral surface of the cylindrical can 5.
It is adapted to be deposited as a magnetic layer on the top.

Further, between the cylindrical can 5 and the crucible 8 and in the vicinity of the cooling can 5, a shutter 11 is provided in a predetermined region of the non-magnetic support 2 which runs at a constant speed on the peripheral surface of the cylindrical can 5. Is arranged so as to cover. The shutter 11 allows the evaporated metal magnetic material 9 to be obliquely deposited on the non-magnetic support 2 within a predetermined angle range.

Further, a gas inlet 12 is provided in the film forming chamber 1 so that a desired gas can be supplied into the film forming chamber 1 at a desired flow rate.

Since the structure of the crucible 8 is characteristic in this vacuum vapor deposition apparatus, it will be described with reference to FIGS. 2 and 3. The crucible 8 is formed such that its length in the longitudinal direction is longer than the width of the peripheral surface of the cylindrical can 5, and as shown in the perspective view of FIG. 2 and the sectional view taken along the line AA ′ in FIG.
Inside thereof, near the liquid surface of the molten liquid of the magnetic metal material 9,
The material supply area 21 and the main melting area 22 are partitioned by a partition plate 23. Here, the main melting region 22 is a region where the electron beam X is irradiated, and the material supply region 21 is a region where pellets are replenished. The main melting region 22 is
The material supply region 2 is provided so as to face the peripheral surface of the cylindrical can 5.
1 is arranged so as not to face the peripheral surface of the cylindrical can 5.

Here, the partition plate 23 has a substantially inverted convex shape,
The base end portion 23b is locked to the opening edge portion of the crucible 8 and the convex portion 23a blocks the opening portion 8a of the crucible 8 to a middle portion in the depth direction. Therefore, the material supply region 21 and the main melting region 22 communicate with each other below the convex portion 23a of the partition plate 23, and the pellets supplied to the material supply region 21 are melted before the convex portion 23a. Will be supplied to the main melting region 22.

Further, in the crucible 8 described above, the storage portion 25 which can be connected to the material supply region 21 via the groove portion 24 is provided at a position not facing the peripheral surface of the cylindrical can 5. Here, the groove 24 is the partition plate 23 described above.
The opening 8a is formed so as to be shallower than a depth at which the material is supplied to the material supply region 21 and the storage portion 25 can be blocked / connected by engaging / disengaging the stopper member 26 with respect to the groove 24. Therefore, in the storage unit 25,
By separating the barrier member 26 from the groove 24, the molten liquid near the liquid surface in the material supply region 21 can be made to flow.

When the crucible 8 is divided into the material supply region 21 and the main melting region 22 in the vicinity of the liquid surface of the melt, even if suspended matter exists in the melt of the pellets replenished in the material supply region, Inflow of suspended solids into the main melting region 22 can be suppressed. Therefore, in the main melting region 22, the surface of the molten liquid is not covered with the suspended matter, and vaporization can be stably performed. Further, if the crucible 8 is used, the pellets will not move to the main melting region 22 while being in a solid state, so that the splash can be suppressed.

Further, by connecting the storage part 25 to the material supply region 21, it is possible to discharge the suspended matter floating in the molten liquid to the storage part 25, so that the main melting region 2
It is possible to prevent the inflow of suspended solids into 2.

In order to form a metal magnetic thin film on the non-magnetic support 2 with the vacuum vapor deposition apparatus having the above-described structure, the film forming chamber 1 is evacuated through the exhaust port to maintain a predetermined degree of vacuum. On the other hand, oxygen gas is introduced from the gas inlet 12 at a predetermined flow rate for the purpose of improving the magnetic properties, durability, and weather resistance of the metal magnetic thin film. Then, the feed roll 3, the cylindrical can 5, and the take-up roll 4 are each rotated at a predetermined speed, and the nonmagnetic support 2 is caused to travel on the peripheral surface of the cylindrical can 5. Further, the metal magnetic material 9 in the crucible 8 may be heated and evaporated by the electron beam X emitted from the electron gun 10, and the shutter 11 may control the incident angle to adhere it to the traveling non-magnetic support 2. .

As the metallic magnetic material 9, a material obtained by melting an ingot previously put in the crucible 8 before the start of film formation is used, and the portion consumed by the film formation is replenished as pellets. Hereinafter, the metal magnetic material 9 supplied as an ingot is referred to as an “initial material”, and the metal magnetic material 9 supplied as a pellet is referred to as a “supplementary material”.

Here, as the metal magnetic material 9, usually,
Any material may be used as long as it is used to form the magnetic layer of the magnetic recording medium, but in the method of manufacturing the magnetic recording medium according to the present invention, a material mainly containing Co is used. Of course, in consideration of magnetic characteristics and rust resistance, various elements represented by Ni, Cr and the like may be added. However, an initial material having an oxygen content of 500 ppm or less is used, and a supplemental material having an oxygen content of 50 to 5000 ppm is used. The metal magnetic thin film to be formed may be a single layer film or a multilayer film.

By the way, as the non-magnetic support to which the above-mentioned metallic magnetic material is applied, polymeric materials such as polyesters, polyolefins, celluloses, vinyls, polyimides and polycarbonates are used. Polymer substrate to be formed, aluminum alloy,
Examples thereof include a metal substrate made of a titanium alloy, a ceramic substrate such as aluminum glass, a glass substrate, and the like, and the shape thereof is not particularly limited. However, when a magnetic tape is manufactured by applying the present invention, a polyethylene terephthalate film, a polyethylene naphthalate film, an aramid film or the like is preferably used as the non-magnetic support. Also,
In these films, a filler may be internally added to control the surface roughness, or a layer for controlling the surface roughness may be formed on the surface.

Further, between the non-magnetic support and the metal magnetic thin film,
Alternatively, when the metal magnetic thin film is composed of a multilayer film, an underlayer or an intermediate layer may be provided in order to improve the adhesive force between the layers and control the coercive force. Further, for example, the vicinity of the surface of the magnetic layer may be an oxide to improve the corrosion resistance.

A protective film layer may be formed on the metal magnetic thin film, and any material may be used as long as it is generally used as a protective film for ordinary metal magnetic thin films. Good. For example, in addition to carbon, C
rO ₂ , Al ₂ O ₃ , BN, Co oxide, MgO, Si
_{O 2, Si 3 O 4,} SiN x, SiC, SiN x -Si
Examples thereof include O ₂ , ZrO ₂ , TiO ₂ , and TiC. These may be a single layer film, a multilayer film, or a composite film.

Of course, the structure of the magnetic recording medium manufactured by applying the present invention is not limited to this, and an undercoat layer may be formed on the non-magnetic support, or the non-magnetic support may be formed, if necessary. A back coat layer may be provided on the main surface of the body opposite to the surface on which the metal magnetic thin film is formed, or a top coat layer made of a lubricant or rust preventive agent may be formed on the surface of the metal magnetic thin film or protective film. You may.

[0040]

EXAMPLES In order to confirm the usefulness of the vacuum vapor deposition apparatus shown in the embodiments and the range of oxygen content usable as a metal magnetic material, the metal magnetic thin film was formed under various conditions below. Magnetic tape was manufactured.

Examples 1 to 6 The steps for actually manufacturing a magnetic tape will be described step by step.

First, a polyethylene terephthalate film having a thickness of 10 μm and a width of 150 mm is prepared, and in order to adjust the surface roughness of this film, a water-soluble latex containing acrylate as a main component is applied to form an undercoat layer. did. As a result, a protrusion density of 10 million pieces / mm ₂ was formed on the surface. This is the non-magnetic support 2.

Then, the film forming chamber 1 of the vacuum vapor deposition apparatus shown in the above-described embodiment is set to 1 × 10 ⁻³ to 10 × 10 ⁻³ Pa.
While maintaining such a vacuum degree, oxygen gas was introduced into the film forming chamber 1 at a flow rate of 3.0 l / min, and the nonmagnetic support 2 was cooled to −30 ° C. at a rate of 25 m / min. The cylinder can 5 was run on the peripheral surface thereof.

In this state, the main melting region 22 of the crucible 8 is irradiated with an electron beam to melt the ingot,
The obtained metal magnetic material 9 was evaporated. Then, this vapor was adhered to the non-magnetic support 2 with an incident angle of 45 ° to 90 °. The output of the electron gun 10 is
200 with the non-magnetic support 2 running at the above speed
The maximum thickness is 3 so that a metal magnetic thin film with a thickness of nm can be formed.
It was adjusted in the range of 00 kW. Since the metal magnetic material 9 in the crucible 8 is consumed during this film formation, pellets were sequentially replenished to the material supply region 21 of the crucible 8. The pellets are melted by the heat transferred from the main melting area 22 and supplied to the main melting area 22 from below the partition plate 23.

Further, during the film formation, the material supply region 2 of the crucible 8
When a floating substance is observed in No. 1, the barrier member 26 is separated from the groove portion 24, the material supply region 21 and the storage portion 25 are connected, and the molten liquid near the liquid surface is caused to flow into the storage portion 25. The suspended matter was discharged to the storage section 25.

As the initial material supplied as an ingot and the supplementary material supplied as pellets, materials a to e having different oxygen contents were used in combination. The compositions of the materials a to e are as shown in Table 1.

[0047]

[Table 1]

After the metal magnetic thin films have been formed as described above, carbon and urethane-based binder are mainly formed on the surface of the nonmagnetic support 2 opposite to the surface on which the metal magnetic thin film is formed. A back coat layer was formed to a thickness of 0.6 μm, and a top coat layer made of perfluoropolyether was formed on the metal magnetic thin film. Then, this was cut into a width of 8 mm to obtain the magnetic tapes of Examples 1 to 6.

Here, the initial material and the replenishing material used when forming the metal magnetic thin film of each magnetic tape are the sample tape of Example 1: Initial material = material a, replenishing material = material b Sample tape of No. 2: Initial material = Material a, Supplementary material = Material c Sample tape of Example 3: Initial material = Material c, Supplementary material = Material b Sample tape of Example 4: Initial material = Material c, replenishing material = material c Sample tape of Example 5: initial material = material a, replenishing material = material d Sample tape of Example 6: initial material = material c, replenishing material = material e .

Embodiments 7 and 8 In this embodiment, when supplying the supplementary material,
A magnetic magnetic thin film was formed in the same manner as in Examples 1 to 6 except that the reducing agent was supplied at the same time to manufacture a magnetic tape.

Here, when the metal magnetic thin film is formed, the material a is used as the initial material and the material d is used as the replenishing material.
A magnetic tape manufactured by supplying Ti of 60 ppm as a reducing agent was used as a sample tape of Example 7, material c was used as an initial material, material e was used as a supplementary material, and 300 ppm of Ti was supplied as a reducing agent. The obtained magnetic tape was used as the sample tape of Example 8.

Comparative Example 1 In this comparative example, a metal magnetic thin film was formed in the same manner as in Examples 7 and 8 except that a material having an oxygen content higher than those in Examples 7 and 8 was used as a supplementary material. Membranes and magnetic tapes were manufactured.

Here, the magnetic tape manufactured by using the material a as the initial material and the material f as the replenishing material when forming the metal magnetic thin film was used as the sample tape of Comparative Example 1. The composition of the material f is as shown in Table 1 together.

Comparative Examples 2 to 9 In Examples 1 to 6 except that a conventional crucible having neither a partition plate 23 nor a storage portion 25 but simply a rectangular parallelepiped opening was used as the crucible. A magnetic magnetic thin film was formed in the same manner as in 1. to produce a magnetic tape.

Here, the initial material and the replenishing material used when forming the metal magnetic thin film of each magnetic tape are the sample tape of Comparative Example 2: Initial material = material a, replenishing material = material a Sample tape of No. 3: Initial material = Material a, Supplementary material = Material b Sample tape of Comparative Example 4: Initial material = Material a, Supplementary material = Material d Sample tape of Comparative Example 5: Initial material = Material c, replenishing material = material a Sample tape of Comparative Example 6: initial material = material c, replenishing material = material b Sample tape of Comparative Example 7: initial material = material c, replenishing material = material d Comparative Example No. 8 sample tape: initial material = material d Sample tape of Comparative Example 9: initial material = material e

Evaluation of Characteristics Here, during the manufacturing process of the sample tapes of Examples 1 to 8 and Comparative Examples 1 to 9 as described above, the film forming rate required at the time of forming the metal magnetic thin film In order to achieve the above, the output of the electron gun 10, the presence or absence of splash, and the presence or absence of suspended matter in the main melting region 22 of the crucible 8 were observed, and the dropout of each manufactured sample tape was measured. The results are shown in Tables 2 and 3.

[0057]

[Table 2]

[0058]

[Table 3]

For the measurement of dropout, a recording / reproducing apparatus (manufactured by Sony Corporation, trade name: EV-S900) was remodeled and each sample tape was reproduced and run to count the number of occurrences of dropout. I went by. Here, the dropout is a state in which an output deterioration of −16 dB or more continues for 10 μsec or more from the reproduction output level. In addition, the measurement is performed for 10 minutes, and the number of times per minute is counted.
The case of 50 to 50 pieces was evaluated as Δ, and the case of 50 or more pieces was evaluated as x.

The presence or absence of splash and the presence or absence of suspended matter are visually observed when the metal magnetic thin film is formed.

From Tables 2 and 3, first, Examples 1 to 6 were prepared.
And Comparative Examples 2 to 9 are compared. As in Comparative Examples 2 to 9,
When a metal magnetic thin film is formed using a conventional crucible,
Splash increases as the oxygen content of the replenishment material increases, and the output of the electron gun 10 for achieving the required film formation rate also increases due to the increase in suspended matter, and the dropout also increases. I understand. On the other hand, when the crucible shown in the embodiment is used as in Examples 1 to 6, even if a crucible having a high oxygen content is used as the supplementary material, the splash is small and the suspended matter is small. It can be seen that the output of the electron gun 10 can be small and dropout can be suppressed. In particular, as in Comparative Example 3 and Example 1, and Comparative Example 4 and Example 5, those having the same initial material and replenishing material are compared with each other, the above-mentioned difference can be clearly seen.

However, as in Examples 5 and 6, when materials d and e having an oxygen content of more than 500 ppm were used as supplementary materials, the amount of suspended solids was larger than in Examples 1 to 4. , Dropout will increase. On the contrary,
Even if the oxygen content of the supplementary material is the same as in Examples 5 and 6, when the reducing agent is supplied as in Examples 7 and 8,
Floats can be reduced and dropouts can be reduced. As a result, the supplemental material has an oxygen content of 50.
It can be seen that it is preferable to use a reducing agent when using a material exceeding 0 ppm. Even if a reducing agent is used as in Comparative Example 1, if the material f having an oxygen content of more than 5000 ppm is used, the suspended solids cannot be sufficiently reduced.

Further, when the comparison in Comparative Examples 2 to 9 is carried out,
Oxygen content is 500 regardless of initial material and supplementary material
It can be seen that when a material exceeding ppm is used, it is necessary to increase the output of the electron gun 10, and dropout also increases. In Comparative Examples 2 to 9, since the conventional type of crucible is used, the suspended matter generated from the supplementary material is present in the electron beam irradiation region. That is, it is desirable that the melt existing in the electron beam irradiation region is a melt of a material having an oxygen content of 500 ppm or less. This indicates that even when the crucible 8 shown in the embodiment is used, it is preferable to use a material having an oxygen content of 500 ppm or less as the initial material.

[0064]

As is apparent from the above description, the use of the vacuum vapor deposition apparatus according to the present invention makes it possible to obtain a high quality metal film with excellent productivity even if suspended matter is generated from the replenishing metal material. Can be formed.

Therefore, when such a vacuum evaporation apparatus is applied to the production of a magnetic recording medium, a high quality metal magnetic thin film can be formed even if a metal magnetic material containing oxygen to some extent is used. Therefore, a high-quality magnetic recording medium can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration example of a vacuum vapor deposition device according to the present invention.

FIG. 2 is a perspective view showing a configuration of a crucible in the vacuum vapor deposition device according to the present invention.

FIG. 3 is a cross-sectional view taken along the line A-A ′ in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deposition chamber 2 Non-magnetic support 5 Cylindrical can 8 Crucible 9 Metal magnetic material 10 Electron gun 21 Material supply region 22 Main melting region 23 Partition plate 24 Groove 25 Reservoir 26 Locking member

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01F 41/20 H01F 41/20

Claims (7)

[Claims] 1. An electron for irradiating at least a cylindrical can for moving a support, a crucible arranged below the cylindrical can, and a metal material filled in the crucible with an electron beam in a film forming chamber. In a vacuum vapor deposition apparatus having a beam irradiation means, the inside of the crucible is, in the vicinity of the liquid surface of the molten liquid of the metal material, a material supply region where the metal material is replenished and a main melting region where the electron beam is irradiated. A vacuum vapor deposition apparatus, which is partitioned and is connected to the material supply region, which is provided with a storage unit that is provided so that a molten liquid near the liquid surface in the region can flow. 2. A metal magnetic material for forming a magnetic layer of a magnetic recording medium is used as the metal material, and the storage section discharges suspended matter suspended in a melt of the metal magnetic material. The vacuum deposition apparatus according to claim 1, which is used. 3. A non-magnetic support is continuously run in a film forming chamber of a vacuum vapor deposition apparatus, and a metallic magnetic material in a crucible is heated and evaporated by irradiation of an electron beam, thereby forming a main surface on the non-magnetic support. When forming the metal magnetic thin film, inside the crucible, in the vicinity of the liquid surface of the melt of the metal magnetic material, to the material supply region where the metal magnetic material is replenished and the main melting region where the electron beam is irradiated. A method of manufacturing a magnetic recording medium, characterized in that a partition is provided and a metal magnetic material containing Co as a main component and containing 50 to 5000 ppm of oxygen is supplied to the material supply region during film formation. 4. The material supply region is connected to a storage portion provided so that a molten liquid near the liquid surface in this region can flow in, and the suspended metal floating in the molten liquid is discharged while the metal magnetism is maintained. The method of manufacturing a magnetic recording medium according to claim 3, wherein a thin film is formed. 5. The metal magnetic material contains 50 to 50 oxygen.
4. The method for producing a magnetic recording medium according to claim 3, wherein the content of 500 ppm is used. 6. As the metal magnetic material, 500 is oxygen.
4. The method of manufacturing a magnetic recording medium according to claim 3, wherein at least one of Al and Ti is supplied as a reducing agent to the material supply region by using a material containing ˜5000 ppm. 7. The crucible is filled with a metallic magnetic material containing Co as a main component and an oxygen content of 500 ppm or less before the formation of the metallic magnetic thin film. A method for manufacturing the magnetic recording medium described.