JPS59141211A - 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 dam members are provided on both the sides interposing the beam irradiating position of a metal evaporation source between them to make a metal vapor current to be concentrated upon the direction of the supporter. CONSTITUTION:An electron beam 7 is scanned on an evaporating material 6 in the width direction A of a film base 1, the evaporating material 6 is made to be in the molten metal condition, and especially the beam irradiating part is heated up to the evaporating temperature to generate a vapor current 8 extending in the width direction A of the film base 1. Therefore the evaporating material 6 at the irraidiating part of the electron beam 7 is reduced to form a recessed part on the molten metal surface of the evaporating material 6. While, the molten metal to flow from the adjoining part into the irradiating part thereof is obstructed by dam members 10, 10 provided at both the sides of the irraiating part thereof, and replenishment of the molten metal to the recessed part is delayed. Accordingly, in the steady state that the evaporating quantity and the replenishing quantity of the evaporating material at the recessed part 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 along the outer circumferential surface of a cylindrical can. 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 between the support and the evaporation source becomes a dog, the distance between the support and the evaporation source becomes a dog, which further reduces the deposition efficiency. 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, 352558 (1964)
), it was necessary to keep the incident angle constant L within the narrowest possible range. For this reason, a shield plate or the like is usually provided between the support and the evaporation source to exclude vapor flow at angles other than the required incident angle, but the provision of this shield plate further reduces the evaporation 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.,
This hindered efforts to significantly reduce costs, and was an important issue to be resolved 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 reflecting wall heated to a temperature higher than the melting point of the vapor deposition material is provided above the crucible, and unnecessary vapor flow is reflected by the reflecting wall to a desired angle of incidence, thereby increasing vapor deposition efficiency. (Japanese Unexamined Patent Publication No. 57-155368), however, since a high-temperature portion is formed over a wide area in this device, 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 replenishes molten metal to both sides of the beam irradiation position of 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. This feature is characterized by the provision of a weir member that prevents the

Note that when manufacturing a magnetic recording medium using the apparatus of the present invention, F 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
-Rh Fe-Cu Co-Cu Co
, -Au, Co -Y, Co-La, Co
-Pr, Co-Gd.

Co-8m, Co-Pt, Ni-
Cu, 4n-B i, Mn-
sb, Mn-A7. Fe-Cr, Co-Cr
, Ni-Cr.

Ferromagnetic alloys such as Fe-Co-Cr, Fe-Co-Ni-Cr, etc. are used. The thickness of the magnetic film is generally about 0.00 mm 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.
2μm to 50μm1 preferably 005μm to 20μm
It is m.

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

When energy beam irradiation to the evaporation source is started by the vacuum evaporation apparatus of the present invention, only this beam irradiation position is intensely heated (heated), the evaporation source in this part evaporates, and the molten metal level in this part 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 apparatus of the invention, a weir member is provided in the molten metal between the beam irradiation positions, so that the molten metal does not easily flow from the area adjacent to the irradiation position to the beam irradiation area where the molten metal surface has been lowered. supply will be delayed. Therefore, in a steady state in which the amount of evaporation from the evaporation source and the amount of replenishment match in the beam irradiated area, the molten metal surface at the beam irradiation position in the beam irradiated area is maintained in a lowered state, more specifically, in a state in which a concave surface is formed. As a result, the distribution of the metal vapor flow from the beam irradiated portion is concentrated in the direction of the center of the curvature of the curved surface, and the efficiency of vapor deposition on the support body disposed in the direction of the center of this curvature can be increased.

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 a magnetic tape is sent out and continuously sent from a roll 2 to a winding roll 4 via a cooling can 3. For example, there is Co-Ni in the crucible 5.
An evaporation material 6 such as an alloy is stored, and this evaporation material 6 is heated by an electron beam 7 from above and becomes a vapor flow 8 which reaches the film base 1 on the cooling can 3 and is deposited on the film base 1. Forms a film. Additionally, a shield plate 9 is provided between the evaporation material 6 and the film base 1.
is provided to eliminate unnecessary steam flow 8'.

In this embodiment, weir members 10.degree. 10 are disposed below the surface of the molten material 6 to sandwich the irradiation position of the electron beam 7. Figure 2 shows a crucible 5 in which this weir member 10.10 is installed.
FIG. 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 weir member 10.10 is also made of ceramic and is disposed on the bottom surface of the crucible 5, extends in the width direction of the film base 1 (direction of arrow A), and is manufactured integrally with the crucible 5.

The electron beam 7 is scanned over the evaporation material 6 in the width direction of the film base 1 (in the direction of arrow A), thereby turning the evaporation material 6 into a molten state, and the beam irradiated area in particular is heated to the boiling point, causing the film base 1 to melt. A steam flow 8 extending in the width direction (arrow A direction) is generated. As a result, the evaporated material 6 in the portion irradiated with the electron beam 7 decreases, and the molten surface of the evaporated material 6 forms a recess. On the other hand, the molten metal flowing into this irradiated part from the adjacent part is absorbed by the weir members 1 provided on both sides of this irradiated part.
0°10, which delays the replenishment of the molten metal into the recess. Therefore, in a steady state where the amount of evaporation material in the recessed portion 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 the coercive force of the magnetic film will be lowered if a component with a small angle of incidence is mixed in. 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 effectively deposited on the support, that is, the deposition efficiency, is extremely reduced. By the way, according to the experiments of the present inventors, Kobal) 80%,
A Co-Ni alloy containing 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 regulated at 30° to perform the evaporation to obtain a magnetic layer with a thickness of 1500°. A”, coercive force 105
The deposition efficiency was 5% when obtaining a magnetic thin film with a squareness ratio of 0.93 for the former four curves.

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-C) suitable as magnetic recording materials
(r, etc.) are very expensive, the cost of the cobalt alloy 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 schematic diagram of a weir member showing another embodiment. The weir members 10a, 10a of this embodiment are arranged on both sides of the irradiation position of the electron beam 7, at intervals from 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. In addition, by engaging with both walls of the crucible 5 facing in the width direction of the support so as to be located below the surface of the molten metal, it is possible to prevent the molten metal from flowing into the beam irradiation area from the area adjacent to the beam irradiation position. This is what I did.

FIG. 4 is a schematic diagram showing a crucible and a weir member used when the support is a disk.

The weir member 10b has a cylindrical shape and is provided at the bottom of the crucible 5b, so that the wall surface of the cylinder surrounds the electron beam irradiation part.
Moreover, the entire member 10b is arranged so as to be 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 10' Torr.

As explained in detail above, the vacuum evaporation apparatus of the present invention is provided with weir members on both sides of the beam irradiation position of the metal evaporation source, thereby making the molten metal surface in the beam irradiation area concave. Since 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 the drawing]

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.
FIG. 3 is a schematic diagram showing another embodiment of the crucible and weir member; FIG. 4 is a schematic diagram showing another embodiment of the crucible and weir member. 1... Support (film base) 3... Cooling can 5.5b... Crucible 6... Evaporation source 7... Electron beam 8... Metal vapor flow 10.10a, iob,... Weir member - 15 = Dimensions 49 - Fig. 3 Fig. 4 (Voluntary) Procedure Neho May 19, 1980 Commissioner of the Patent Office Lord 2, Name of invention Vacuum evaporation device 3, Person making amendment case Related Patent Applicant Address 210 Nakanuma, Minamiashigara City, Kanagawa Prefecture Name Name
Fuji Photo Film Co., Ltd. 4, Agent 5, without date of amendment order 1) Correct "boiling point" on page 10, line 8 of the specification to [evaporation temperature]. -5 [

Claims (4)

[Claims] (1) In a vacuum evaporation apparatus that forms a magnetic metal thin film by depositing a metal vapor flow obtained by heating an evaporation source with an energy beam under reduced pressure on the surface of a non-magnetic support, the beam of the metal evaporation source A vacuum evaporation apparatus characterized in that a weir member is provided on both sides of an irradiation position to prevent the supply of molten metal to the irradiation position. (2) The weir member is provided at the bottom of the evaporation source container, has an upper surface, and extends uniformly in the width direction of the support.
The vacuum evaporation apparatus according to claim 1, characterized in that the projection is a strip. (3) The weir member is a two-striped columnar member supported by both widthwise opposing walls of the support body of the evaporation source container. Vacuum deposition equipment. (4) The weir member is an annular member centered on a point on a line extending in the depth direction from the beam 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.