JP2000045064A - Vapor deposition device for producing recording medium, and crucible for vapor deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of a splush in a vapor deposited material stored in a crucible for vapor deposition at the time of film-forming a thin film magnetic layer on a recording medium such as a magnetic tape under a vacuum. SOLUTION: In the vapor deposition device for producing a recording medium provided with a vacuum tank 2 whose inside is held in a vacuum state, means 3 to 7 provided in the vacuum tank 2 and to be loaded with a stock 8a for a recording medium, a crucible 21 for vapor deposition set in the vacuum tank 2, and in which a bottomed storing part 21b storing a vapor deposited material 10 for forming a film on the stock 8a for a recording medium is formed on the side of the upper face 21a and an electron gun 11 fitted to the vacuum tank 2, emitting an electron beam 12 toward approximately the center part of the bottomed storing part 21b of the crucible 21 for vapor deposition, melting the vapor deposited material 10 in the bottomed storing part 21b and evaporating it to the side of the stock 8a for a recording medium, the approximately center part of the bottom face 21b1 in the bottomed storing part 21b of the crucible 21 for vapor deposition is projected compared to the peripheral bottom face to suppress the generation of a splush in the vapor deposited material 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a thin film magnetic layer or the like on a recording medium such as a magnetic tape in a vacuum.
The present invention relates to a vapor deposition apparatus for producing a recording medium and a crucible for vapor deposition capable of suppressing generation of splash (bumping) of a vapor deposition material contained in a vapor deposition crucible.

[0002]

2. Description of the Related Art In recent years, thin-film magnetic tapes have attracted attention as magnetic tapes applied to digital video / audio tape recorders and the like in order to achieve high density and thin film.

At present, the thin film magnetic tape has a magnetic film formed by an oblique evaporation method. This is, specifically,
An electron beam emitted from a pierce-type electron gun or the like in a vapor deposition device for producing a recording medium is used to deposit Co or CoN in a crucible for vapor deposition.
i, etc., to irradiate a vapor-deposited material (hereinafter referred to as a metal magnetic material) to melt and evaporate the metal magnetic material, and to introduce PET, PEN, PI (polyimide), P while introducing oxygen.
A thin film magnetic layer made of CoO, CoNiO, or the like is formed on the base film by attaching it to a base film such as A (polyamide).

FIG. 5 is a structural view showing the structure of a general vapor deposition apparatus for producing a recording medium to which the oblique vapor deposition method is applied, and FIG.
5A to 5C are diagrams for explaining a conventional vapor deposition crucible installed in the vapor deposition apparatus for manufacturing a recording medium shown in FIG. 5, wherein FIG. 5A is an external perspective view and FIG. (C) is a cross-sectional view taken along the line YY in (A) of FIG.

[0005] As shown in FIG. 5, a general vapor deposition apparatus for manufacturing a recording medium to which the oblique vapor deposition method is applied (hereinafter, referred to as an apparatus).
The inside of one vacuum chamber 2 is kept in a vacuum state. In the vacuum chamber 2, a tape supply roll 3 and a tape winding roll 4
, Tape guide rolls 5 and 6 and cooling can roll 7
And the rolls 3 to 7 are rotatably arranged.
A base film 8a serving as a recording medium material of the thin film magnetic tape (recording medium) 8 is wound along the base film 8a, and the base film 8a moves from the tape supply roll 3 to the tape take-up roll 4 in a direction indicated by an arrow in the drawing. I am running. On this occasion,
A cooler (not shown) is provided inside the cooling can roll 7, and suppresses deformation and the like of the base film 8a due to a temperature rise during vapor deposition.

[0006] In the vacuum chamber 2, obliquely below the cooling can roll 7, MgO (magnesia) is used as a crucible material.
A crucible for vapor deposition (hereinafter, referred to as a crucible) 9 formed in a box shape by using is provided. In the above-mentioned crucible 9, a bottomed accommodation portion 9b accommodating a metal magnetic material 10 such as Co or CoNi is formed on the upper surface 9a side, and a bottom surface 9b1 in the bottomed accommodation portion 9b is formed flat. . On this occasion,
The longitudinal direction (vertical direction to the paper surface) of the bottomed storage portion 9b of the crucible 9 is the width direction (vertical direction to the paper surface) of the base film 8a.
It is installed to correspond to.

A crucible 9 is provided on the side wall 2a of the vacuum chamber 2.
A piercing type electron gun 11 for melting and evaporating the metal magnetic material 10 housed therein is attached. In this pierced electron gun 11, the electron beam 12 is emitted toward the center of the bottomed housing 9b of the crucible 9, and the bottomed housing 9
b) to melt the metallic magnetic material 10 in the base film 8a.
Has evaporated to the side.

When the base film 8a runs, the maximum incident angle θmax of the metal magnetic material 10 deposited from the crucible 9 with respect to the base film 8a is determined by the incident angle limiting mask 1.
3, and the minimum incident angle θmin is set to a predetermined angle by the incident angle regulating mask 14, respectively. Further, a nozzle 14 is provided inside the incident angle regulating mask 14.
N is attached, and oxygen is injected from the nozzle 14N toward the evaporated metal magnetic material 10.

The electron beam 12 emitted from the pierce-type electron gun 11 is controlled by a deflection magnet 15 for applying a deflection magnetic field to a trajectory and a deflection magnet 16 provided near the crucible 9. Therefore, by scanning the electron beam 12 in the longitudinal direction of the bottomed accommodating portion 9b of the crucible 9, the evaporated metal magnetic material 10 such as Co or CoNi is deposited on the base film 8a in the width direction of CoO or CoNi.
The film is formed as a thin film magnetic layer made of NiO or the like, and this is repeated in the length direction of the base film 8a to obtain a long thin film magnetic tape 8 on the tape winding roll 4 side.

[0010]

When a thin film magnetic layer is formed on the base film 8a in the vacuum chamber 2 of the apparatus 1 to manufacture the thin film magnetic tape 8, the metal magnetic material 10
Is melted in the crucible 9 when the metallic magnetic material 1 is melted.
Splash (bumping) caused by high-melting impurities such as oxides and carbon contained in oxygen, or air or gas trapped in minute pores inside the metal magnetic material 10. There is.

At this time, as shown in FIGS. 6A to 6C, the box-shaped crucible 9 has a metal magnetic material 10 on the upper surface 9a side.
Is formed, and the bottom surface 9b1 in the bottomed housing portion 9b is formed flat, so that the entire surface of the molten metal magnetic material 10 is covered with oxide, carbon, or the like. Are separated from each other.

At this time, if a splash occurs in the molten metal magnetic material 10 in the bottomed accommodating portion 9b of the crucible 9, the thin film magnetic layer formed on the base film 8a becomes defective, and the thin film magnetic tape 8 is When recording / reproducing with a video / audio / tape recorder,
This may cause a dropout or error in the recorded / reproduced signal.

Therefore, in order to suppress the generation of the splash, conventionally, a method of weakening the intensity of the electron beam 12 emitted from the pierced electron gun 11 to reduce the impact on oxides and high melting point impurities is adopted. . However, the above-described method for suppressing the splash does not sufficiently take into consideration the enhancement of the production efficiency of the thin-film magnetic tape 8.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a first invention is a vacuum chamber having an inside maintained in a vacuum state, and a vacuum chamber provided in the vacuum chamber and having a recording medium. Means for mounting a medium material, installed in the vacuum chamber,
A crucible for vapor deposition formed on the upper surface side with a bottomed accommodation portion for accommodating a vapor deposition material for applying a film to the recording medium material; and a substantially central portion of the bottomed accommodation portion of the crucible for vapor deposition attached to the vacuum chamber. An electron gun that emits an electron beam toward the recording portion and melts the vapor deposition material in the bottomed storage portion and evaporates the vaporized material toward the recording medium material. A vapor deposition apparatus for manufacturing a recording medium, wherein a substantially central portion of a bottom surface in a bottomed storage portion of a crucible is projected from a peripheral bottom surface to suppress a splash of the vapor deposition material.

According to a second aspect of the present invention, there is provided a bottomed storage section which is installed in a vapor deposition apparatus and stores a vapor deposition material on an upper surface side,
A vapor deposition crucible characterized in that a substantially central portion of a bottom surface in the bottomed housing portion protrudes from a peripheral bottom surface.

[0016]

1 to 4 show an embodiment of a vapor deposition apparatus and a crucible for vapor deposition for producing a recording medium according to the present invention.
This will be described in detail with reference to FIG.

FIG. 1 is a structural view showing the structure of a vapor deposition apparatus for producing a recording medium according to the present invention. FIG. 2 is a view for explaining a vapor crucible according to the present invention. ,
(B) is a sectional view taken along line XX of (A), and (C) is a sectional view taken along line Y- of (A).
FIG. 3 is a sectional view taken along the line Y-Y for explaining the operation of the crucible for vapor deposition according to the present invention.

For the sake of convenience, the same components as those shown in the conventional example will be denoted by the same reference numerals and will be described as appropriate, and new components different from those in the conventional example will be described. In this embodiment, different points from the conventional example will be mainly described.

The vapor deposition apparatus for producing a recording medium (hereinafter referred to as an apparatus) 20 according to the present invention shown in FIG. 1 is different from the general vapor deposition apparatus 1 for producing a recording medium described above with reference to FIG. , A crucible for vapor deposition (hereinafter referred to as a crucible) 21 described later
The shape of the crucible 2 is the same as before
Reference numeral 1 is installed diagonally below the cooling can roll 7.
The other components are the same as the conventional ones, and the tape supply roll 3 is used as a means for mounting the base film (recording medium material) 8a of the thin film magnetic tape (recording medium) 8 in the vacuum chamber 2.
, A tape winding roll 4, and tape guide rolls 5, 6
And a cooling can roll 7 are rotatably arranged, and a pierce-type electron gun that melts the metal magnetic material 10 (evaporation material) in the crucible 21 on the side wall 2a of the vacuum chamber 2 and evaporates it to the base film 8a side 11 is attached.

Here, as shown in FIGS. 2A to 2C in an enlarged manner, the evaporation crucible 21 according to the present invention is formed using MgO (magnesia) as in the prior art. In addition, a bottomed accommodation portion 21b accommodating a metal magnetic material 10 for forming a thin film magnetic layer on the base film 8a of the thin film magnetic tape 8 is formed on the upper surface 21a side.

Then, an electron beam 12 is emitted from the pierced electron gun 11 attached to the side wall 2a of the vacuum chamber 2 toward the center of the bottomed receiving portion 21b of the crucible 21. The metal magnetic material 10 in 21b is melted and evaporated.

Here, the point different from the conventional one is that the bottom surface 21b of the bottomed storage portion 21b formed on the upper surface 21a side of the crucible 21
1 is made to protrude from the peripheral bottom surface so that
b2 is formed. Thus, crucible 2
By forming the protruding portion 21b2 substantially at the center of the bottom surface 21b1 of the bottomed receiving portion 21b, the heat capacity of the protruding portion 21b2 is reduced, so that the temperature of the protruding portion 21b2 becomes higher than other portions.

As a result, as shown in FIG.
In the one bottomed storage portion 21b, convection of the molten metal magnetic material 10 occurs from the central portion toward the outer peripheral portion (side wall portion). Then, in the bottomed receiving portion 21b of the crucible 21, an oxide or a high melting point impurity which causes a splash (bumping) in the molten metal magnetic material 10 is removed from the side wall portions 21b3 and 21b4 of the bottomed receiving portion 21b. In the direction of the side wall 2
It is deposited on top of 1b3 and 21b4. Therefore, crucible 2
The electron beam 12 emitted from the pierce-type electron gun 11 toward the center of the bottomed receiving portion 21b is formed on the side wall portion 21b.
Since it does not hit the oxide or the high melting point impurity deposited on the upper part of 3, 21b4, the generation of splash (bumping) can be suppressed. Therefore, it is not necessary to weaken the intensity of the electron beam 12 emitted from the pierce-type electron gun 11 as compared with the conventional case, and the base film 8a of the thin-film magnetic tape 8 remains thin while the intensity of the electron beam 12 is increased. Since the layers can be coated, the thin film magnetic tape 8
Production efficiency can be increased.

<Embodiment> FIG. 4 is a view showing a state of generation of a splash of a vapor deposition material (metal magnetic material) in the shape of the crucible for vapor deposition according to the present invention and the shape of a comparative example.

2 (B) and 2 (C), a is a longitudinal dimension of the bottomed storage portion 21b formed on the crucible 21, b
Is the dimension in the short direction of the bottomed storage portion 21b formed on the crucible 21, and c is the distance from the upper surface 21a of the crucible 21 to the bottomed storage portion 21b.
The depth dimension to the bottom 21b1 in b, d is the bottom 21b1
Is a height dimension based on the bottom surface 21b1 of the protruding portion 21b2 formed substantially at the center. In addition, it is the same as the conventional one that the longitudinal direction (vertical direction to the paper surface) of the bottomed accommodation portion 21b of the crucible 21 corresponds to the width direction (vertical direction to the paper surface) of the base film 8a.

In the embodiment and the comparative example (conventional example) which is compared with this embodiment, the respective dimensions of the bottomed accommodation portion 21b of the crucible 21 are set as follows.

That is, in both the embodiment and the comparative example,
The dimension a in the longitudinal direction of 1b is fixed to 600 mm, the dimension b in the transversal direction is fixed to 150 mm, and the depth method c is fixed to 70 mm. On the other hand, the protrusion formed in the substantially central portion of the bottom surface 21b1 of the bottomed storage portion 21b. The height d of the portion 21b2 is set to 0 mm in the comparative example, and 10 mm, 20 mm, and 30 m in the example.
Five types of experiments were performed while varying the parameters to m, 40 mm, and 50 mm.

At this time, MgO (magnesia) is used as the material of the crucible 21, and the metallic magnetic material 1 in the crucible 21 is used.
Using Co (cobalt) as 0, the electron beam 12 was supplied to the crucible 21 at a power of 50 kW by focusing on one point substantially at the center of the bottomed accommodating portion 21b.

Then, from the crucible monitoring window (not shown) of the vacuum chamber 2, the state of the splash of the metallic magnetic material 10 stored in the bottomed storage portion 21b of the crucible 21 was monitored. Here, as shown in FIG. 4, the number of splashes that can be visually observed was determined as × for 10 or more per minute, Δ for 2 to 9 and ○ for 1 or less. As a result, it was found that by forming the protruding portion 21b2 substantially at the center of the bottom surface 21b1 of the bottomed accommodation portion 21b, generation of the splash of the molten metal magnetic material 10 was suppressed.

Incidentally, a disk-shaped disk may be used as a recording medium material mounted in the vapor deposition apparatus 20 for producing a recording medium.
Furthermore, the crucible 21 for vapor deposition installed in the vapor deposition device 20 can be applied to any material capable of vapor deposition, and its external shape is not limited.

[0031]

According to the vapor deposition apparatus and the crucible for producing a recording medium according to the present invention described in detail above, the substantially central portion of the bottom surface in the bottomed accommodating portion of the vapor deposition crucible installed in the vacuum chamber is surrounded by the peripheral portion. Because it protrudes from the bottom surface, convection of the vapor deposition material that has melted in the bottomed container occurs, and oxides and high-melting impurities that cause splash (bumping) in the vaporized material are removed from the side walls in the bottomed container. The electron beam emitted from the electron gun does not hit the oxide or high melting point impurities deposited on the upper part of the side wall because it moves in the direction and deposits on the upper part of the side wall.
Splash generation can be suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a vapor deposition apparatus for manufacturing a recording medium according to the present invention.

2A and 2B are views for explaining a crucible for vapor deposition according to the present invention, wherein FIG. 2A is an external perspective view, and FIG. 2B is XX of FIG.
FIG. 3C is a cross-sectional view of FIG.

FIG. 3 is a YY cross-sectional view for explaining the operation of the crucible for vapor deposition according to the present invention.

FIG. 4 is a view showing a state of occurrence of a splash of a deposition material (metal magnetic material) in the shape of the crucible for vapor deposition according to the present invention and the shape of a comparative example.

FIG. 5 is a configuration diagram showing a configuration of a general vapor deposition apparatus for manufacturing a recording medium to which an oblique vapor deposition method is applied.

6A to 6C are views for explaining a conventional crucible for vapor deposition installed in the vapor deposition apparatus for manufacturing a recording medium shown in FIG. 5, and FIG. 6A is an external perspective view, (B) is (A)
(C) is a cross-sectional view taken along the line YY in (A) of FIG.

[Explanation of symbols]

2: vacuum chamber, 3: tape supply roll, 4: tape take-up roll, 5: tape guide roll, 6: tape guide roll, 7: cooling can roll, 8: recording medium (thin film magnetic tape), 8a: recording medium Material (base film), 10
... Evaporation material (metal magnetic material), 11 ... Electron gun (pierce type electron gun), 12 ... Electron beam, 20 ... Evaporation apparatus for manufacturing recording medium, 21 ... Crucible for evaporation (crucible), 21a ... Top surface, 21b ... Yes Bottom accommodation section, 21b1 ... bottom face, 21b2 ...
Projecting portions, 21b3, 21b4 ... side wall portions.

Claims (2)

[Claims] A vacuum chamber whose inside is maintained in a vacuum state; a means provided in the vacuum chamber for mounting a material for a recording medium; and a film installed in the vacuum chamber and forming a film on the material for a recording medium. A crucible for vapor deposition formed on the upper surface side with a bottomed accommodation portion for accommodating an evaporation material for attachment, attached to the vacuum chamber, and an electron beam directed substantially toward the center of the bottomed accommodation portion of the crucible for evaporation. An electron gun that emits light and melts the vapor deposition material in the bottomed storage part and evaporates the material to the recording medium material side, wherein the vapor deposition crucible has a bottomed storage part. A vapor deposition apparatus for manufacturing a recording medium, wherein a substantially central portion of the bottom surface is made to protrude from a peripheral bottom surface to suppress a splash of the vapor deposition material. 2. A bottomed housing portion which is installed in a vapor deposition apparatus and houses a vapor deposition material is formed on an upper surface side, and a substantially central portion of a bottom surface in the bottomed housing portion is protruded from a peripheral bottom surface. Crucible for vapor deposition.