JPS59141209A - Vacuum deposition device - Google Patents

Abstract

PURPOSE:To enhance metal deposition efficiency to the surface of a supporter, and to reduce cost of the whole of a magnetic recording medium by a method wherein cooling members extending to the width direction of the supporter are provided at both the sides interposing the beam irradiating position of a metal evaporation source between them. CONSTITUTION:An electron beam 7 is scanned on an evaporating material 6 in the width direction A of a film base 1, accordingly the evaporating material 6 is made to be in the molten metal condition, and especially the beam irradiating part is heated up to the boiling point to generate a vapor current 8 extending in the width direction A of the film base 1. Accordingly, the evaporating material 6 at the irradiating part of the electron beam 7 is reduced to form a recessed part on the molten metal surface of the evaporating material 6. While, when cooling members 10 are water-cooled, the molten metal adjoining to the irradiating part of the electron beam 7 is cooled to enhance viscosity, and replenishment of the molten metal to the recess part is delayed. Consequently, in the steady state that the evaporating quantity and the replenishing quantity of the evaporating material are equalized, the molten metal surface of the irradiating part of the electron beam 7 becomes to form a recessed surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a vapor deposition apparatus used for vacuum vapor deposition, and particularly in a vapor deposition apparatus that heats and evaporates an evaporation source using an energy beam such as an electron beam.

In recent years, as the amount of information to be recorded has increased, the demand for high-density magnetic recording has become even stronger, and vacuum evaporation has replaced the conventional coating-type production method in which a binder-type magnetic liquid is coated on a flexible support and dried. Various studies have been conducted on so-called non-coating manufacturing equipment that deposits a ferromagnetic metal thin film on the support without using a binder using methods such as sputtering, ion blating, etc., and various proposals have been made for practical application. is being done.

Among these non-coating type manufacturing equipment, oblique incidence vacuum evaporation equipment, in which the evaporation beam of magnetic metal is incident obliquely on the support surface, has a relatively compact processing process and has good magnetic properties. It is practical because a thin film with specific characteristics can be obtained.

This oblique incidence vacuum evaporation apparatus generally moves the support above the evaporation source in a straight line or in a curved manner over the outer circumferential surface of a cylindrical can, and has a very limited oblique incidence angle at the evaporation source. The method is characterized in that a ferromagnetic metal thin film is deposited on the support surface to a specified thickness at one time by an evaporated metal flow, but since the support surface and the evaporated metal flow are located obliquely relative to each other, , compared to the case where the incident angle is zero (incidence perpendicular to the support surface), the deposited film thickness is a cosine (Co51ne) times as large, and the vapor deposition efficiency decreases significantly as the incident angle increases. This is unavoidable, and if the angle of incidence becomes narrow due to the geometric arrangement of the support and the evaporation source, the distance between the support and the evaporation source becomes large, and the deposition efficiency further decreases. It was something. In addition, the magnetic properties of the deposited film, especially the coercive force, depend on the angle of incidence (Reference: 5chued
e: J, A, P, 35 25583- (1964,)), it was necessary to keep the incident angle constant within as narrow a range as possible. For this reason, a shield plate or the like is usually provided between the support and the evaporation source.
Although vapor flows at angles of incidence other than the desired are excluded, the provision of this shield plate further reduces the vapor deposition efficiency.

This decrease in vapor deposition efficiency is caused by relatively expensive non-ferrous metals such as C.
When using O, Co-Ni, Co-Ni-Cr, etc., it is difficult to achieve significant cost reduction, and this is an important problem to be solved for practical use.

In order to improve the low vapor deposition efficiency of conventional devices, a device has been proposed in which the side wall of the crucible, which is the container for the evaporation source, is raised to regulate the distribution of vapor flow. The cooled metal is deposited on top of the
It becomes difficult to continue vapor deposition.

Additionally, a device has been proposed in which a reflective wall heated to a high temperature higher than the melting point of the vapor deposition material is provided above the crucible, and unnecessary vapor flow is reflected by the reflective wall to a desired angle of incidence, thereby increasing the vapor deposition efficiency. (Unexamined Japanese Patent Publication No. 57-1
No. 55368), but this device has a high temperature portion over a wide area, so there is a problem that radiant heat from this high temperature portion heats other members in the device and has an adverse effect.

The present invention has been made in view of the above circumstances, and aims at improving the efficiency of vapor deposition of a magnetic material onto a support in an oblique incidence vacuum evaporation apparatus.

The vacuum evaporation apparatus of the present invention has a metal evaporation source that deposits a metal vapor flow onto a support such as a film by heating by irradiation with an energy beam such as an electron beam. It is characterized by providing at least two cooling members extending in the direction.

When the vacuum evaporation apparatus of the present invention starts irradiating the evaporation source with an energy beam, only this beam irradiation position is strongly heated, the evaporation source in this area evaporates, and the molten metal level in this area lowers.

At this time, if the entire evaporation source is a molten metal with low viscosity, the molten metal in the area adjacent to this irradiation position will flow into the beam irradiated area where the molten metal surface has fallen, so the molten metal surface will always be kept almost horizontal. According to the device of the invention, a cooling member is placed in the molten metal with the irradiation position in between, and the molten metal adjacent to the irradiation position is cooled to increase its viscosity. The molten metal does not easily flow into the beam irradiated portion where the molten metal level has been lowered, and therefore the molten metal level at the irradiation position is maintained in a lowered state. Further, the energy beam scans the evaporation source in the width direction of the support, and the molten metal surface eventually has a concave surface extending in the width direction of the support. Thereby, the distribution of the vapor flow is concentrated toward the center of the curvature of the curved surface, and the efficiency of vapor deposition onto the support can be increased.

In addition, when manufacturing a magnetic recording medium using the apparatus of the present invention, P is used as the ferromagnetic metal for forming the magnetic thin film.
Metals such as e, Co, Ni or Fe-Co, Fe-
Ni, Co-Ni, Fe-Co-Ni, Fe
-R, h, Fe-Cu, Co-Cu, C.

=Au, Co-Y, Co-La, Co-Pr,
Co-Gd.

Co-8m, Co-Pt, Ni-Cu,
Mn-B i, Mn-8b, Mn-AA! ,
Fe-Cr, Co-Cr, Ni-Cr, Fe-C
Ferromagnetic alloys such as o-Cr, Fe-Co-Ni-Cr, etc. are used. The thickness of the magnetic film is generally about 0.02μ because it needs to be thick enough to provide sufficient output as a magnetic recording medium and thin enough to be sufficient for high-density recording.
m to 5.0 μm, preferably 0.05 μm to 2.0
It is p m.

Further, as the support, plastic pastes such as polyethylene terephthalate, polyimide, polyamide, polyvinyl chloride, cellulose triacetate, polycarbonate, and polyethylene naphthalate can be used.

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

FIG. 1 is a side sectional view showing one embodiment of the present invention. For example, a long film base 1 for magnetic tape is sent out,
From roll 2 to winding roll 4 via cooling carrier/3
are sent continuously. For example, the crucible 5 contains C0-N
An evaporation material 6 such as i-alloy is accommodated, and this evaporation material 6 is heated by an electron beam 7 from above and becomes a vapor flow 8 that reaches the film base 1 on the cooling can 3 and is deposited on the film base 1. Form a vapor deposited film.

Further, a shield plate 9 is provided between the evaporation material 6 and the film base 1 to eliminate unnecessary vapor flow 8'.

In this embodiment, a cooling member 10.10 is disposed below the surface of the molten material 6 to sandwich the irradiation position of the electron beam 7 therebetween. FIG. 2 is a schematic diagram of the crucible 5 in which this cooling member 10.10 is arranged. The crucible 5 is made of ceramic and has a long shape in the width direction of the film base 1 (in the direction of the arrow). The cooling member 10.10 is made of Cu, which does not form an alloy with CO, and is disposed on the wall facing the bottom of the crucible 5 and the length of the film base 1 in the width direction of the film base 1 (in the direction of the arrow). It is a tubular member that extends from the outside and allows water to flow from the outside.

The electron beam 7 scans the evaporation material 6 in the width direction of the film base 1 (in the direction of the arrow), thereby turning the evaporation material 6 into a molten state, and the beam irradiated area in particular is heated to the boiling point and spreads across the width of the film base 1. A steam flow 8 is generated extending in the direction (in the direction of the arrow). As a result, the evaporated material 6 in the portion irradiated with the electron beam 7 is reduced, and the molten surface of the evaporated material 6 forms four parts. On the other hand, when the cooling member 10 is water-cooled, the molten metal adjacent to the portion irradiated with the electron beam 7 is cooled and its viscosity increases, which delays the replenishment of the molten metal into the recess.

Therefore, in a steady state where the amount of evaporation material is equal to the amount of replenishment, the surface of the molten metal in the portion irradiated with the electron beam 7 forms a concave surface.

The distribution of the vapor flow released from the molten metal surface into the vacuum is c
It is known that it is proportional to osθ·cosψ (θ is the angle between the vapor flow and the normal to the molten metal surface, and ψ is the angle between the vapor flow and the normal to the support). For this reason, the vapor flow emitted from the concave surface has a distribution that is concentrated toward the center of the curvature of the concave surface. By the way, in oblique incidence vacuum evaporation equipment, there is a close relationship between the angle of incidence on the support and the magnetic properties, especially the coercive force, and if a component with a small angle of incidence is mixed in, the coercive force of the magnetic film will be lowered. A shield plate 9 blocks vapor flows 8' at angles of incidence other than the desired one.

For this reason, the proportion of the metal evaporated stream evaporated from the crucible 5 that is not effectively deposited on the support, that is, the deposition efficiency is extremely reduced. Incidentally, according to experiments conducted by the present inventors, a Co-Ni alloy containing 80% cobalt and 20% nickel was used as the evaporation material, a 15 μm thick polyester base film was used as the support, and the incident angle of the evaporation flow was 30
The magnetic layer thickness was 1500 A,
The deposition efficiency was 5% when obtaining a magnetic thin film with a coercive force of 1-0500e and a BH curve squareness ratio of 0.93.

However, in this example, the molten metal surface in the beam irradiation area is formed into a concave surface as described above, and the film base 1 is placed near the center of the curvature of this concave surface, so that the evaporation rate is significantly greater than in the past. Efficiency can be improved. According to an experiment conducted using this example under the same conditions as the experiment described above, it was possible to improve the vapor deposition efficiency to 8%. By the way, alloys mainly composed of cobalt (Co, Co-Ni, Co-Ni-
Cr, etc.) are very expensive, so the cost of cobalt alloys accounts for a large proportion of the total cost of a magnetic recording medium, such as a vapor-deposited video tape.

However, according to this embodiment, the vapor deposition efficiency can be significantly improved as described above, and therefore the cost of the entire magnetic recording medium can be significantly reduced.

FIG. 3 is a side sectional view of a crucible and a cooling member showing another embodiment. In this embodiment, the cooling members 10a,], Oa are built in on both sides of the irradiation position of the electron beam 7, and in the side walls and bottom wall of the crucible 5, which face each other in the length direction of a support such as a film base. There is. Note that this cooling member 1
It is desirable that 0 a and 10 a be arranged so that a part of their surfaces are in contact with the vapor deposition material.

Another embodiment shown in FIG. 4 is a cooling member 10b.

10b on both sides of the irradiation position of the electron beam 7, spaced apart from the side walls and bottom wall of the crucible 5 facing in the length direction of a support such as a film base, and positioned below the surface of the molten metal. By providing the member 10b.

The entire surface of the job is in contact with the vapor deposition material.

The embodiments shown in FIGS. 3 and 4 can also provide the same effects as the embodiment shown in FIG. 2.

FIG. 5 is a schematic diagram showing a crucible and a cooling member used when the support is a disk. The cooling member 10C has a cylindrical shape and is disposed so that the wall surface of the cylinder surrounds the electron beam irradiated portion and the entire member 10C is located below the surface of the molten metal. When electron beam irradiation is started using this embodiment, the molten metal surface of the irradiated portion becomes a bowl-shaped concave surface, and the metal vapor flow from here forms a distribution concentrated in the direction of the center of the curvature of this concave surface. This makes it possible to improve the efficiency of vapor deposition onto a disk centered near the center of this curvature. In this case, since the disk is arranged at an angle with respect to the vapor flow, it is desirable to rotate the disk itself during the vapor deposition period to make the thickness of the vapor deposited film on the surface of the disk uniform.

The chamber (vacuum chamber) of this device is roughly pumped using a rotary pump, and once pumped using a booster pump, etc.
It is necessary to maintain the pressure at about 0 to l Q i'orr.

As explained in detail above, the vacuum evaporation apparatus of the present invention is provided with cooling members extending in the width direction of the support on both sides of the beam irradiation position of the metal evaporation source, and this cools the molten metal in the beam irradiation area. Since the surface is concave so that the metal vapor flow is concentrated in the direction of the support, the efficiency of metal vapor deposition onto the support surface can be improved. Furthermore, by improving the deposition efficiency, the cost of the entire magnetic recording medium can be significantly reduced, and the practical value is extremely high.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG. 2 is a schematic diagram showing one embodiment of the present invention.
3 and 5 are schematic views showing another embodiment of the crucible and the cooling member; FIG. 4 is a side view showing still another embodiment of the crucible and the cooling member. FIG. 1... Support (film base) 3... Cooling can 5... Crucible 6... Evaporation source 7... Electron beam 8... Metal vapor flow

Claims (4)

[Claims] (1) Vacuum deposition equipment that forms a magnetic metal thin film by evaporating the metal vapor flow obtained by irradiating a metal evaporation source with an energy beam under reduced pressure and heating the evaporation source on the surface of a non-magnetic support. A vacuum evaporation apparatus characterized in that two cooling members extending in the width direction of the support are provided on both sides of the beam irradiation position of the metal evaporation source. (2) The vacuum evaporation apparatus according to claim 1, wherein the cooling member is disposed on a bottom of the container and a side wall of the support body that faces each other in the length direction. (3) The cooling member is disposed in the evaporation source at a distance from the bottom surface of the container and the longitudinally opposing side wall surface of the support. The vacuum evaporation apparatus according to scope 1. (4) The cooling member is an annular member centered at a point on a line extending in the depth direction from the irradiation position, and is arranged so as to be located below the surface of the molten metal of the evaporation source. A vacuum evaporation apparatus according to claim 1.