JPH10124869A - Device for producing magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the efficiency of vapor deposition and to prevent a waste of a magnetic material by putting a lid on a vapor diffusion controlling means, keeping the means in a closed state during heating and melting, opening the means at the time when a prescribed temp. is attained and carrying out vapor deposition on a film. SOLUTION: A vapor deposition chamber 9 and a winding chamber 8 are evacuated by a pump and electric power is supplied from a high-frequency power source to a high-frequency coil 12 to heat and melt a magnetic material 10 in the fireproof crucible 11a of an evaporating source 11. At this time, a lid 30 is put on a vapor diffusion controlling means 15 opening upward and the means 15 is kept in a closed state during the heating and melting so as to prevent the sticking of metallic vapor to a base film 3. Particles evaporated during this waiting stick to the surface of the inner wall of the lid 30, melt further and return to the crucible 11a. At the time when the required rate of evaporation is attained after the waiting, the base film 3 is sent from a sending shaft 5, the lid 30 is lifted off by driving an opening and closing means 31 and a magnetic film is formed on the base film 3 through a gas blowing part 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a magnetic recording medium, and more particularly, to a method of heating and melting a metal material, evaporating the metal material, and depositing the vapor stream on a flexible substrate such as a base film. The present invention relates to an apparatus for manufacturing a magnetic recording medium in which a magnetic recording layer is formed by performing the method.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, γ-Fe
₂ O ₃ , Co-doped Fe ₃ O ₄ , γ-Fe ₂ O ₃
Magnetic material as a berthollide compound of Fe ₃ O _4, berthollide compound doped with Co, from CrO _3, Ba oxide magnetic material such as ferrite, or Fe, Co, an alloy magnetic material mainly composed of Ni or the like Particles are dispersed and mixed together with additives in an organic binder such as a vinyl chloride-vinyl acetate copolymer, a styrene-butadiene copolymer, an epoxy resin, a polyurethane resin, and the dispersion mixture is mixed with a polyester such as polyethylene terephthalate (PET). 2. Description of the Related Art A so-called coating type magnetic tape is widely known, which is manufactured by coating a base film (substrate) made of polyolefin such as polypropylene or polypropylene and then drying the base film.

On the other hand, in recent years, the demand for higher recording density has become stronger, and the density of the magnetic material in the magnetic layer of the magnetic recording medium has been increased, the coercive force has been improved, the magnetic layer has been made thinner, or the frequency characteristics have been shortened. Improvements such as shifting to the wavelength side have been made. However, in the coating type tape, since the binder remains in the magnetic layer, it is difficult to satisfy the above-described conditions required for high-density recording.

Accordingly, attention has been paid to a method of manufacturing a magnetic recording medium by a vapor deposition method such as vacuum deposition, sputtering, or ion plating, or a plating method such as electroplating or electroless plating, and various proposals have been made. According to these methods, the magnetic layer can be formed by depositing and growing a magnetic material directly on a substrate without using a binder, so that the packing density of the magnetic material in the magnetic layer is increased, and Can also be made thinner.

In addition, these vapor deposition methods and the like make it easy to control the adjustment of the film thickness formed on the base film, adjust the coating solution of the magnetic layer in the manufacturing process of the coating type tape, and perform drying after coating. This has practically useful advantages such as eliminating the need for processing steps associated with the formation of a magnetic layer.

In particular, the vapor deposition method has the advantages that the waste liquid treatment required in the plating method is unnecessary and that the growth rate of the deposited magnetic film is high.
A magnetic tape using a magnetic layer formed on a base film by such a vapor deposition method as a recording layer has a much higher reproduction output and a shorter frequency characteristic of a recording signal than a conventional coating type magnetic tape. It is useful as a high-density magnetic recording medium, for example, it is improved on the wavelength side.

The production of a magnetic recording medium by a vapor deposition method can be performed in detail by, for example, a vacuum vapor deposition apparatus 1 shown in FIG. As shown in FIG. 10, a vacuum evaporation apparatus 1 has a cylindrical outer shape and a non-magnetic material such as a polyester film, a polyamide film, a polyimide film, etc. A cooling can 4 for winding a long base film 3 made of a material in the longitudinal direction is provided. The cooling can 4 is rotated in the direction of arrow Y to send out the base film 3 and send the base film 3 from the shaft 5 side to the winding shaft 6 side. Conveyed to.

The inside of the vacuum chamber 2 is wound by a partition plate 7 into a winding chamber 8 for feeding and winding the base film 3.
And a deposition chamber 9 for depositing a magnetic material on the base film 3. In the vapor deposition chamber 9, Co, CoNi alloy, CoCr alloy, CoC
An evaporation source 11 provided with a magnetic material 10 such as an rNi alloy is provided, and the magnetic material 10 is heated and evaporated by heating means 12 such as electron gun heating, resistance heating, and high-frequency induction heating. The particles of the magnetic material 10 as a vapor flow that evaporate and rise (referred to as magnetic particles or evaporating particles) are formed as a magnetic layer on the surface of the base film 3 that is conveyed in the direction of arrow Y with the rotation of the cooling can 4. Deposit continuously.

Here, in order to efficiently deposit the evaporated magnetic material particles on the substrate to increase the vapor deposition efficiency, it is sufficient to prevent the evaporated particles from diffusing widely. According to the technology disclosed in Japanese Patent Application Laid-Open No. 2-56730, a cylindrical shape is provided between the evaporation source and the cooling can so that the peripheral wall surrounds a portion through which the evaporated particles pass. What is necessary is just to provide the vapor flow diffusion control means (sometimes simply called vapor diffusion control means) 15. The vapor diffusion control means 15 has an inner wall surface for re-evaporating or collecting and collecting the evaporated particles of the magnetic material 10 attached to the inner wall surface, or for combining re-evaporation and collecting and collecting. Means for heating or cooling the temperature.

When such a cylindrical vapor diffusion control means 15 is provided, it is difficult to use an electron gun heating means generally used as a heating means. In other words, in this case, it is necessary to secure the trajectory of the electron beam from the electron gun to the magnetic material 10 in the evaporation source 11.
This is because, if the vapor diffusion control means 15 is provided above 11, it is difficult to secure a passage trajectory of the electron beam. Therefore, high frequency induction heating means is usually used as the heating means.

On the other hand, the above-mentioned vapor diffusion control means prevents the diffusion of the vapor flow by its inner wall surface. On the other hand, the vapor flow contacts the inner wall surface, and the evaporated magnetic material adheres to the inner wall surface. There is a risk of solidification. When the magnetic material adheres and solidifies on the inner wall surface, the vapor flow distribution becomes different from the intended vapor flow distribution, and maintenance such as a recovery operation of the deposited magnetic material is required. Therefore, in the above method, a heating source is added to the vapor diffusion control means, the inner wall surface of this means is set to a temperature equal to or higher than the boiling point of the magnetic material, and the magnetic material which collides with the inner wall surface of the vapor diffusion control means and adheres to the inner wall surface Are re-evaporated so that they can merge with other vapor streams.

However, since the scattering direction of the magnetic material particles re-evaporated from the inner wall surface of the vapor diffusion control means is different from the scattering direction of the other magnetic material particles, the originally intended steam flow distribution cannot be obtained and the deposition efficiency is reduced. Was likely to be caused. On the other hand, a manufacturing process of a magnetic recording medium for forming a magnetic thin film on a flexible substrate as used in the present invention is generally called oblique deposition.

The purpose of the oblique deposition is to grow a magnetic crystal deposited on a flexible substrate at an oblique angle with respect to the vertical direction of the flexible substrate, and to improve magnetic properties such as coercive force. The point is to improve. Therefore, the re-evaporated magnetic material particles adhering to the flexible substrate at an arbitrary angle hinder stable crystal growth in oblique vapor deposition, and may cause instability of magnetic characteristics. .

Therefore, by adjusting the temperature of the inner wall surface of the vapor diffusion control means to a temperature higher than the melting point of the magnetic material constituting the steam flow and lower than the boiling point, the magnetic material adhering to the inner wall surface of the vapor diffusion control means is adjusted. Particles are liquefied without being re-evaporated and descend along the inner wall surface, whereby the vapor flow from the upper opening of the vapor diffusion control means contains particles of the magnetic material re-evaporated from the inner wall surface of the vapor diffusion control means. A method for manufacturing a magnetic recording medium has been proposed in which a high vapor deposition efficiency is maintained without disturbing the vapor flow distribution by the vapor flow of the re-evaporated magnetic material (see Japanese Patent Application Laid-Open No. HEI 9-64572). 2-56730).

On the other hand, in such a magnetic recording medium manufacturing apparatus, the magnetic material of the evaporation source is melted when the apparatus is started so that the magnetic material is not deposited on the base film until a sufficient evaporation rate is obtained. The shutter means 25 may be provided as shown by the broken line 11. The shutter means 25 includes a mask 13 provided on the front of the cooling can 4,
It is curved according to the shape of 14, and the masks 13, 14
It is provided so that the opening defined by can be opened and closed. Thereafter, the shutter means 25 is set to the closed position as shown in FIG. 11 until the temperature of the magnetic material of the evaporation source is melted and a sufficient evaporation rate is obtained, and after a sufficient evaporation rate is obtained, Move in the direction of arrow A. As a result, the openings defined by the masks 13 and 14 are exposed, and a magnetic material is deposited on the base film 3.

[0016]

However, in the above-described apparatus for manufacturing a magnetic recording medium provided with the shutter means, the evaporated particles which evaporate until a sufficient evaporation rate of the magnetic material is obtained are obtained on the surface of the shutter means. In this case, the adhered material is solidified and adhered, so that the adhered material is wasted and the use efficiency of the magnetic material is significantly reduced. Further, when the magnetic material of the evaporation source is completely dissolved and the temperature is raised to a temperature at which a constant evaporation rate can be secured, the base film is conveyed, and at the same time, the shutter means is moved and set to the open position. At that time, the magnetic material adhered to the shutter means surface is separated from the shutter means by the impact of the movement, and falls into the evaporation source or closes the evaporation port of the vapor diffusion prevention means, and the evaporation rate or evaporation is caused. A large change is caused in the film thickness distribution of the magnetic material, so that efficient vapor deposition cannot be performed or a magnetic recording medium having a uniform film thickness cannot be formed.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a magnetic recording medium manufacturing apparatus capable of manufacturing a magnetic recording medium having a uniform thickness by improving the vapor deposition efficiency.

[0018]

According to the present invention, there is provided an apparatus for manufacturing a magnetic recording medium, comprising: transport means for transporting a long flexible substrate in a vacuum atmosphere; An evaporation source made of a magnetic material, an evaporation unit for heating and evaporating the evaporation source, and a diffusion direction of the vapor flow heated and evaporated by the evaporation unit, disposed between the evaporation unit and the flexible substrate. A magnetic thin film is formed on the flexible substrate, comprising: a cylindrical vapor flow diffusion control unit for controlling and regulating; and an incident angle restricting unit for restricting an incident angle of the vapor flow to the flexible substrate. An apparatus for manufacturing a magnetic recording medium, wherein an openable / closable lid is provided at an opening of the cylindrical vapor flow diffusion control means on a side facing the flexible substrate. It is composed of a device.

Further, in the above apparatus, it is preferable that the inner surface of the lid is made of a metal, an oxide, a carbide, a nitride, a boride and a silicide, and more preferably an oxide having a melting point of 1800K or more. .

Further, in the above-mentioned device, it is desirable to provide a control means for controlling an inner surface temperature of the lid,
It is desirable that the control means can control the temperature of the inner surface of the lid to be equal to or higher than the melting point of the magnetic material.

The lid closes an opening of the vapor flow diffusion control means facing the flexible support until the temperature of the magnetic material reaches a temperature at which a predetermined vapor deposition rate can be obtained. After reaching the temperature at which the deposition rate can be obtained,
It is desirable to operate at a timing such that the opening is opened.

The temperature of the magnetic material may be measured by using a known means such as a radiation thermometer or a thermocouple.

The term “evaporation source” as used herein means a material formed of a magnetic material. In the present specification, for convenience of explanation, the term “evaporation source” includes an evaporation container containing the magnetic material as the evaporation source. It may be called an evaporation source.

[0024]

In the apparatus for manufacturing a magnetic recording medium according to the present invention, an openable / closable lid is provided at the upper end of the vapor diffusion control means, so that the magnetic material of the evaporation source can obtain a sufficient evaporation rate. By closing the lid until the temperature is reached, the lid is heated together with the vapor diffusion control means while the lid is closed, so that the magnetic material does not solidify and adhere to the lid. As a result, when the lid is opened and the magnetic material is deposited, the solidified magnetic material falls into the evaporation source and blocks the evaporation port, and the thickness distribution of the manufactured magnetic recording medium changes. Disappears. Also, since the evaporated magnetic material does not solidify, it returns to the evaporation source again along the inner surface of the lid and further on the inner surface of the vapor diffusion control means,
The magnetic material is not wasted. Thus, the utilization efficiency and the evaporation rate of the magnetic material can be improved.

By providing a control means for controlling the inner surface temperature of the lid, the temperature of the inner surface of the lid can be positively controlled in accordance with the temperature (eg, melting point) at which the magnetic material does not solidify. Can be eliminated.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a magnetic recording medium manufacturing apparatus according to an embodiment of the present invention.
FIG. 1 shows a schematic configuration of an embodiment of a vacuum evaporation apparatus which is a magnetic recording medium manufacturing apparatus of the present invention.

The illustrated vacuum vapor deposition apparatus 1 has a cylindrical cooling can 4 inside a vacuum chamber 2, and a cylindrical film (outer peripheral surface) of the cooling can 4 has a base film 3 as a substrate of a magnetic recording medium. Is wound. The base film 3 is made of a polyester such as polyethylene terephthalate (PET) or polyethylene naphthalate, a polyolefin such as polypropylene, a cellulose dielectric such as cellulose triacetate or cellulose diacetate, a vinyl resin such as polyvinyl chloride,
It is formed by processing a plastic such as polycarbonate, polyamide, or polyphenylene sulfide into a long film, and the thickness thereof is, for example, 3 to 100 μm.

An undercoat is applied to the surface of the base film 3 if necessary. The undercoat is made of a binder (cellulose such as methylcellulose, P
Saturated polyesters such as ET, phenoxy resins, polyamides, polyacrylates, etc.) and fillers (silica, titania, alumina, calcium carbonate, etc.) are dissolved and applied. so,
It has protrusions with a density of 5 million to 100 million / mm ² . The height and density are appropriately selected depending on the required adhesion performance and the like.

Further, the base film 3 may be subjected to a pretreatment such as a glow discharge treatment, an ion irradiation treatment, a heat treatment, and a chemical treatment.

The base film 3 is wrapped around the take-up shaft 6 from the delivery shaft 5 through the cylindrical surface of the cooling can 4, and is rotated on the cylindrical surface of the cooling can 4 by rotating the cooling can 4 in the Y direction. For example, it is conveyed at a speed of 10 to 200 m / min, and is taken up by the take-up shaft 6. The cooling can 4 has a diameter
It is a cylindrical drum of 800 mm and width of 400 mm, the surface of which is hard chrome plated and mirror-polished to 0.2 S or less, and has a structure in which cooling water and other refrigerants (for example, ethylene glycol) are circulated inside. Is maintained at, for example, −35 to + 25 ° C.

On the surface of the cooling can 4, masks 13 and 14 whose main body is formed of SUS304 or the like are provided, circulating cooling water or a coolant inside the cooling can 4 at a predetermined distance. This distance is between 2 and 15 mm, more preferably between 2 and 10 mm, most preferably between 3 and 5 mm. 2mm
If it is narrower, the space for installing the first gas blowing section described later cannot be secured, and if it is more than 15 mm, the vapor flow goes between the mask and the base film and adheres to the cooling can 4, causing contamination. Because. This is because the heat transfer coefficient between the can and the base film changes in the portion where the dirt has occurred, or the base film is insufficiently adhered to the can and is easily damaged by heat. And base film 3
The maximum incident angle (θmax) is defined by the mask 13 located on the upstream side in the transport direction, and the minimum incident angle (θmin) is defined by the mask 14 located on the downstream side. The angle of incidence is based on the center of the circle of the melted surface in the refractory crucible 11a described later,
The maximum incident angle (θmax) defined by the angle between the line segment from the center of the circle to the edge of the mask 13 and the edge of the mask 14 and the normal line at the position of each mask edge on the cooling can 4 and regulated by the mask 13 Has an upper limit of 90 °, more preferably 87 °, most preferably an upper limit of 85 °, and the mask 14
It is desirable that the minimum incident angle (θmin) regulated by the above is set to a lower limit of 20 °, more preferably 25 °, and most preferably 30 °. This is because a desired holding power cannot be obtained if the above range is not satisfied. mask
The opening width of the mask opening 18 formed by 13 and 14 in the width direction (direction perpendicular to the transport direction of the base film 3) can be set arbitrarily.

The vacuum chamber 2 includes a winding chamber 8 for feeding and winding the base film 3 by a partition plate 7,
The base film 3 is partitioned into a deposition chamber 9 for depositing a magnetic material. Each of the winding chamber 8 and the vapor deposition chamber 9 is provided with an exhaust system (not shown) for vacuuming, and the degree of vacuum in each chamber can be individually adjusted. In particular, since the oxidizing gas described below is introduced into the vapor deposition chamber 9 from outside the vacuum chamber 2, the degree of vacuum in the chamber and the partial pressures of various residual gases are constantly adjusted.

The take-up chamber 8 contains the base film 3.
For the pre- and post-treatments described above, for example, glow discharge treatment device, ion irradiation treatment device, heat treatment device, C
A VD processing device or the like may be provided. In addition, cooling can 4
Is not limited to a cylindrical shape, and may be an endless belt-shaped metal plate capable of forming a predetermined slope with respect to the evaporation source 11.

An evaporation source 11 provided with a magnetic material 10 is disposed below the cooling can 4 in the vapor deposition chamber 9. Around the evaporation source 11, an inside for heating the magnetic material 10 is provided. A high frequency induction heating coil 12 having a structure in which cooling water circulates is provided. Further, a high frequency power supply 13 for supplying high frequency power to the high frequency induction heating coil 12 and a high frequency power supply feeder 21 for transmitting high frequency power are provided.

The magnetic material 10 is made of, for example, Fe, Co, Ni,
CoNi, FeCo, FeCu, FeCr, CoCr,
CoCu, CoAu, CoPt, CoW, NiCr, C
oV, MnBi, MnAl, CoFeCr, CoNiC
r, CoRh, CoNiPt, CoNiFe, CoNi
It is appropriately selected from ferromagnetic metals and ferromagnetic alloys such as FeB, FeCoNiCr, and CiNiZn.

The refractory crucible 11a containing the magnetic material 10, which is a component of the evaporation source 11, is made of, for example, MgO, Zr
O ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , ThO ₂ , B
N, BeOCaO stabilized ZrO ₂ , Y ₂ O ₃ stabilized Zr
It is appropriately selected from ceramics such as O ₂ , carbon or a carbon compound, and other heat-resistant materials. The shape of the refractory crucible 11a is a container shape having a bottom, and the horizontal cross-sectional shape may be a true circle, an ellipse, an oval, a square, a rectangle, or any other shape, and the vertical cross-section may be a square. , Rectangular, trapezoidal, or any other shape. The high-frequency induction heating coil 12 is a refractory crucible 11.
Preferably, the shape corresponds to the side surface of a.

Further, the peripheral wall of the vapor deposition chamber 9 surrounds a path between the cooling can 4 and the evaporation source 11 having the magnetic material 10 and through which a vapor flow generated by evaporation of the magnetic material 10 passes. The vapor diffusion control means 15 is provided as described above, and an acidizing gas or an oxidizing gas and an inert gas (for example, N ₂ Ar gas) are provided near the cooling can 4 and near the masks 13 and 14.
A first gas blowing unit 17 for blowing a mixed gas of the gaseous mixture toward the base film 3 is provided. Further, an oxidizing gas,
Alternatively, a second gas blowing unit 16 for blowing a mixed gas of an oxidizing gas and an inert gas toward the evaporated particles is provided.

The gas blowing section 17 is located downstream with respect to the transport direction of the base film 3 and is built in the surface of the mask 14 on the side of the cooling can 4 near the mask 14 that regulates the minimum incident angle (θmin). ing. The blowing direction of the gas blowing slit 17a is a cooling can 4 that defines the minimum incident angle (θmin).
The direction is substantially parallel to the tangent line on the cooling can 4 at the upper reference point. The oxidizing gas is blown from the gas blowing unit 17 so that the oxidizing gas is blown in a substantially oblique direction with respect to the scattering direction of the evaporated particles that have passed through the opening of the vapor diffusion control means 15 described later, and a part of the evaporated metal particles. To oxidize.

The inner peripheral wall of the vapor diffusion control means 15 is made of, for example, MgO, ZrO ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , T
hO ₂ , BN, BeOCaO stabilized ZrO ₂ , Y ₂ O ₃
Evaporation steam flow path formed of ceramics such as stabilized ZrO ₂ , carbon or carbon compound, or other heat-resistant material and surrounded by a regulating surface extending substantially vertically in a state substantially continuous with the refractory crucible 11a The lower surface and the upper surface are opened to allow the passage of the evaporated particles of the magnetic material 10 and to improve the directivity thereof,
It is a cylindrical shape having only a peripheral wall, and the horizontal cross-sectional shape may be circular, elliptical, oval, square, rectangular, or any other shape. The vertical cross-section may also be square, rectangular, trapezoidal, or any other shape.

Further, the vapor diffusion control means 15 has a laminated structure composed of a plurality of members such as three layers of an inner wall portion 15a, an intermediate portion 15b, and an outer peripheral portion 15c on a concentric circle from the center of the opening to the outside. ing.

The vapor diffusion control means 15 includes a refractory crucible 11a.
Evaporated particles of the magnetic material 10 that evaporate from the center point in the melt surface and fly upward from the point set as the reference point are used as a mask 13 for controlling the maximum incident angle and a mask for controlling the minimum incident angle, which will be described later. It is configured so as not to prevent adhesion in a continuous range from the maximum incident angle θmax to the minimum incident angle θmin defined by 14.

The refractory crucible 11a, the high-frequency induction heating coil 12, the high-frequency power supply 20, the high-frequency feeder 21 and the like are merely examples of the evaporation source, and the base film 3 extends in the width direction (perpendicular to the transport direction in the plane of the base film 3). When the width of the evaporation source 11 is large, the shape of the evaporation source 11 is changed according to the width of the base film 3 (for example, when the horizontal cross-sectional shape of the evaporation source 11 is elliptical and the width of the base film 3 is wide). The long axis direction of the elliptical shape of the evaporation source 11 is adjusted to the width direction of the base film 3), and a plurality of sets of the evaporation sources 11 arranged in the width direction of the base film 3 may be adopted. In this case, the evaporation source 11 (including the refractory crucible 11a), the high-frequency induction heating coil 12, the high-frequency power supply 20, the high-frequency feeder 21
Or a plurality of sets of the evaporation sources 11 are arranged independently, and a high-frequency induction heating coil 12, a high-frequency power supply 20,
It is also possible to adopt a configuration in which the high-frequency feeder 21 is shared.

Further, in the apparatus for manufacturing a magnetic recording medium according to the present invention, a lid 30 capable of opening and closing the upper end is provided upstream of the vapor diffusion control means 15. This lid 30 is a single open type lid as shown in FIG. A lid 31 is provided at the tip of an arm 32 pivotally attached to the opening / closing means 31. The arm 32 pivots in the direction of arrow A to open and close the upper end of the vapor diffusion control means 15. . Further, in a portion where the lid 30 and the vapor diffusion control means 15 are in contact with each other, the upper part of the vapor diffusion control means 15 has a key shape so that a gap is not formed, and the lid 30 enters into the upper part.

As shown in FIG. 3, the lid 30 is formed by laminating an intermediate body 30b and an inner wall plate 30a to a lid body 30c made of ceramic or the like. Further, since the inner wall plate 30a is exposed to a high temperature, it is preferable that the inner wall plate 30a is made of a metal, an oxide, a carbide, a nitride, a boride and / or a silicide having a melting point of 1800 ° K or more. Table 1 below shows specific examples of the material forming the inner wall portion 30a.

Table 1 Oxides MgO, ZrO ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , ThO ₂ , TiO ₂ , BeO, SiO ₂ , CaO stabilized ZrO ₂ , Y ₂ O ₃ stabilized ZrO ₂ , LaCrO ₃ , UO ₂ , Cr ₂ O ₃ carbide B ₄ C, SiC, TiC, HfC, NbC, VC, WC, TaC, ZrC nitride BN, TiN, ZrN, TaN hydride ZrB ₂ , TiB ₂ , TaB ₂ silicon MoSi ₂ , preferably, MgO, Y ₂ O ₃ , CaO stabilized Z
rO ₂ , which is Y ₂ O ₃ stabilized ZrO ₂ , most preferably Y ₂ O ₃ stabilized ZrO ₂ (Y ₂ O ₃ : 5.0% to 12.0
%, ZrO ₂ : 88.0% to 95.0%, weight ratio).

As shown in FIG. 4, the lid 30 has a SUS in which cooling water, liquid nitrogen, liquid helium, and a refrigerant (Freon, brine, ethylene glycol, etc.) 33a are circulated.
A cooling mechanism 33 composed of 304 or the like may be provided. In this case,
It is preferable to use a graphite product carbon board as a heat conductor as the intermediate body 30b without providing the lid body 30c. Further, it is preferable to provide a thermocouple 35 made of Wa ₅ Re ₅ or the like in order to change the degree of cooling by measuring the temperature of the lid 30.

Further, the lid 30 may be provided with a heating means 34 as shown in FIG. 5 so that the magnetic material 10 attached to the inner wall plate 30a is easily evaporated. In this case, as the heating method,
Known methods such as heater heating and high-frequency induction heating may be used, but in the case of performing heater heating, it is preferable to use graphite carbon having a specific resistance of 700 to 1500 μΩ-cm as the heating means 34. Further, a thermocouple 35 made of Wa ₅ Re ₅ or the like may be provided in order to measure the temperature of the lid 30 and change the degree of heating, similarly to the lid pair 30 having the cooling mechanism shown in FIG. preferable.

Further, both the cooling mechanism 33 and the heating means 34 may be provided.

Since it is preferable to return the magnetic material 10 evaporated from the evaporation source 11 to the evaporation source 11 as much as possible, the lid 30 is heated to such an extent that the magnetic material 10 attached to the lid 30 is completely evaporated. Is preferred. The degree of this heating is such that the melting point of the magnetic material 10 is as shown in Table 2 below, so that the inner surface temperature of the lid 30 is 1800 ° K or more, preferably
It is preferably at least 2000 ° K, more preferably at least 2200 ° K.

Table 2 Materials Melting point (° K) Fe 1810 Co 1767 Ni 1728 The melting point of the material contained in the alloy is Cu 1357.6 Cr 2118 Au 1337.6 Pt 2045 W 3660 Mn 1517 Al 933.5

[0051]

EXAMPLE A refractory crucible 11a of this example has a cup shape (inner diameter φ80 mm, outer diameter φ95 mm, height 100 mm, internal depth 92 mm).
mm) and the material is Y ₂ O ₃ stabilized ZrO ₂ (Y
₂ O ₃ ; 5.0% to 12.0%, ZrO ₂ ; 88.0% to 95.0%)
Was used. Co ₁₀₀ was used as the ferromagnetic material 10 for evaporation inside the refractory crucible 11a.

The high-frequency induction heating coil 12 is composed of a Cu pipe having a diameter of φ12 mm through which cooling water circulates. The high-frequency induction heating coil 12 has eight turns, an inner diameter of φ120 mm, and a height h105 mm. Two high-frequency power supplies 20 having an oscillation frequency of 25 kHz and an output of 30 kW are installed outside the vacuum chamber 2, and two high-frequency power sources provided inside the vacuum chamber 2 through a high-frequency feeder 21 and a vacuum feedthrough (not shown). Connected to heating coil 12. The high-frequency feeder 21 is made of a Cu plate, and the extended Cu pipe portions of the high-frequency induction heating coil 12 are each surrounded by an insulating tube made of Al ₂ O ₃ and are electrically insulated from each other.

The inner wall 15a of the vapor diffusion control means 15 was cylindrical (inner diameter φ80 mm, outer diameter φ95 mm, height h75 mm), and was made of ZrO ₂ . The intermediate portion 15b was cylindrical (inner diameter φ95mm, outer diameter φ114mm, height h75mm), and was made of graphite carbon or BN.

The outer peripheral portion 15c has a cylindrical shape (inner diameter φ114 mm,
Outer diameter φ200 mm, height h75 mm), 18 ° C inside
Was circulated, and a cooling structure having a main body made of Cu was used.

Next, a comparison result between the magnetic recording medium manufacturing apparatus of the present invention and a conventional magnetic recording medium manufacturing apparatus will be described.

First, as a conventional example, as shown in FIG. 11, the masks 13 and 14 have a curved shape along the masks 13 and 14 on the front surface thereof and are spaced apart from the masks 13 and 14 by a distance of 8 mm. A function of preventing evaporated metal particles of the magnetic material 10 from adhering to the surface of the base material 3, circulating cooling water of 18 ° C. inside, and a movable shutter means 25 made of SUS304 as a main body. Was arranged.

The procedure for forming the ferromagnetic metal thin film is as follows. The vapor deposition chamber 9 and the winding chamber 8 are evacuated using a cryopump (not shown), and are maintained at 5.0 × 10 ⁻⁵ Torr. The magnetic material 10 was heated and melted by supplying electric power to the high frequency coil 12 using two sets of high frequency power supplies 13.
The temperature of the shutter 25 was set to the "closed" position during the temperature rise and the melting from the start of the melting, and the state in which the metal vapor was not attached to the base film 3 was maintained.

The heating method of the magnetic material 10 is as follows: the transport speed of the base film 3 is 80 m / min, and the oxygen introduction amount is 1800 cc / min.
Preliminary tests were conducted on the input power in a steady state sufficient to maintain the evaporation rate at which the film thickness was 1600 angstroms under the conditions of minute and width, and the holding time until the evaporation rate was obtained. The holding time is the time from the start of supplying a certain amount of electric power to the time when the temperature of the magnetic material 10 is raised and dissolved, and until the entire evaporation source is sufficiently heated to reach a thermal equilibrium state until a constant evaporation rate can be maintained. Say. As a result of the preliminary test, the initial power value and holding time
15KW, 30 minutes.

The evaporating particles which evaporate during the holding time adhere to the front surface of the shutter means 25. Thereafter, the base film 3 is sent out from the feed shaft 5 under the condition of a conveying speed of 80 m / min and a tension of 10.0 kgf / 300 mm, and the side where the magnetic thin film of the base film 3 is formed in the pre-treatment chamber (not shown). After performing the glow discharge treatment using the _two gases, it was transported on the cooling can 4. Then, by driving the shutter means 25 to the state of "open", the 1600 Angstrom on the base film 3 while injecting O ₂ gas simultaneously injecting charge 1800cc / min, width from the gas blowing part 17 Co
After forming the —O magnetic thin film, the base film 3 is wound around a winding shaft 6. After continuously forming a metal thin film of 3000 m in length, the shutter means is set to the "closed" state,
At the same time, injection of O ₂ gas from the gas blowing unit 17 and high frequency power supply
The power supply from 20 was stopped and the film formation was completed.

After depositing a magnetic thin film on the base film 3, a mixture of a phosphoric acid lubricant + a perfluoropolyether lubricant and a rust inhibitor (benzotriazole) is dissolved and applied to the surface of the magnetic thin film. . A non-magnetic powder containing carbon black as a main component, a mixed material of nitrocellulose, polyester, and polyurethane, and an isocyanate curing agent were dissolved and dispersed on the back surface, and applied to a thickness of 0.5 μm.

After a series of vapor deposition steps was completed, the solidified vapor deposited on the front surface of the shutter means 25 was sampled and weighed. The residual ferromagnetic material 10 in the refractory crucible 11a
Was measured, and the evaporated weight was calculated. As a result, the ratio (η%) of the weight of the deposit adhering to the front surface of the shutter means 25 to the total weight evaporated was η = 15.5%.

On the other hand, in the apparatus for manufacturing a magnetic recording medium according to the present invention, the same base film 3, magnetic material 10, and evaporation source 11 as those of the above-described conventional apparatus except that the lid 30 is provided on the vapor diffusion control means 15. Were used.

The procedure for forming the ferromagnetic metal thin film is as follows. The vapor deposition chamber 9 and the take-up chamber 8 are evacuated using a cryopump (not shown) and maintained at 5.0 × 10 ^-5 Torr.
The magnetic material 10 was heated and melted by supplying electric power to the high-frequency coil 12 using the two sets of high-frequency power supplies 13. The temperature of the lid was raised from the start of the melting, and during the melting, the lid 30 was set to the “closed” position, and the base film 3 was kept in a state in which metal vapor did not adhere.

During the heating and melting of the magnetic material 10, the set values of the inner wall temperature (Tcup ° K) of the lid 30 and the inner wall temperature (Twall ° K) of the vapor diffusion control means 15 were set as shown in Table 3. . Measurement of the inner wall surface temperature using thermocouples _{φ1.0 mm (W 95 Re 5)} .

The control of the inner wall surface temperature is performed when cooling is necessary.
℃ cooling water, and when heating is necessary, an embedded carbon heater (CIP molded product specific resistance 15
(00 μΩ-cm).

Incidentally, the power value to be initially supplied and the holding time were determined to be 15 KW and 30 minutes, respectively, as in the above-described conventional example.

The evaporation particles that evaporate during the holding time are
Adhered to the inner wall of 30 and fixed or melted at the same time, refractory crucible
It will be recycled into 11a.

After the holding time has elapsed and the required evaporation rate has been obtained, the base film 3 is moved from the delivery shaft 5 to 80 m / m.
At a transport speed of 10.0 kgf / 300 mm and a pre-treatment chamber (not shown).
After the glow discharge treatment using O ₂ gas was performed on the side on which the magnetic thin film was formed, the substrate was transported on the cooling can 4. Then, the opening / closing means 31 is driven to set the lid 30 to the “open” state,
At the same time, the gas spraying unit 17 sprays O ₂ at 1800 cc / min.
After forming a 800 Å Co-O magnetic thin film on the base film 3 while injecting gas, the base film 3 is wound around a winding shaft 6. Continuous length 30
After the formation of the metal magnetic thin film having a thickness of 00 m, the lid 30 was closed, and at the same time, the injection of the O ₂ gas from the gas blowing unit 17 and the supply of power from the high-frequency power supply 20 were stopped to terminate the film formation.

After depositing the magnetic thin film on the base film 3, a mixture of a phosphoric acid lubricant + a perfluoropolyether lubricant and a rust inhibitor (benzotriazole) is applied to the surface of the magnetic thin film by dissolving it. A nonmagnetic powder containing carbon black as a main component, a mixed material of nitrocellulose, polyester, and polyurethane, and an isocyanate curing agent were dissolved and dispersed on the back surface, and applied to a thickness of 0.5 μm.

After this series of vapor deposition steps is completed, the lid 30
The weight was measured including the deposit on the inner wall, and the attached deposit weight was calculated from the increased weight. In addition, refractory crucible 11a
The weight of the remaining ferromagnetic material 10 in the sample was measured, and the weight that evaporated was calculated. Table 3 shows the results of calculating the ratio (η%) of the weight of the deposit adhering to the inner wall of the opening / closing lid to the total weight evaporated under each condition.

Table 3 Tcup (° K) Twall (° K) η% Conventional Example-1 −2000 ° K 15.5% Example-1 1700 ° K 2000 ° K 12.7% Example-2 1800 ° K 2000 ° K 10.0 % Example-3 2000 ° K 2000 ° K 7.6% Example-4 2200 ° K 2000 ° K 6.3% Example-5 2400 ° K 2000 ° K 5.7% Example-6 2200 ° K 2200 ° K 5.5% Example-7 2400 ° K 2200 ° K 5.0% Example-8 2200 ° K 2400 ° K 4.8% Example-9 2400 ° K 2400 ° K 4.5% Tcup (° K); Temperature inside the inner wall of opening / closing lid Twall (° K): Temperature in the inner wall of the vapor diffusion control means η; Evaporation amount (g) / (amount (g) attached to the front surface of the shutter or the inner wall of the opening / closing lid) × 100 As can be seen from Table 3, compared with the conventional example It can be seen that the value of η is lower in the present embodiment, and the utilization efficiency of the magnetic material 10 is better. Also, as the inner surface temperature of the lid 30 increases, the magnetic material 10
It can also be seen that the utilization efficiency of is high.

In the embodiment described above, the cover 30
Is used as a single open type,
For example, as shown in FIG. 6, the lid 30 may be slid at the upper end of the vapor diffusion control means 15 in the direction of arrow B to open and close the lid 30, and as shown in FIG. Lid 30 ', opening and closing means 3
A double open type lid may be provided by providing 1 'and an arm 32'. When a plurality of vapor diffusion control means 15 are provided as shown in FIG. 8, a multi-open type in which a plurality of lids 30 are provided in accordance with the number of vapor diffusion control means is preferable.

The shape of the lid 30 may be hemispherical as shown in FIG. 9A or FIG. 9B so that the droplets of the magnetic material 10 attached to the lid 30 may easily fall. As shown in FIG.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a magnetic recording medium manufacturing apparatus according to the present invention.

FIG. 2 is a diagram showing details of a vapor diffusion control means.

FIG. 3 is a diagram showing details of a lid provided in the vapor diffusion control means.

FIG. 4 is a diagram showing an embodiment in which a cooling mechanism is provided on a lid.

FIG. 5 is a view showing an embodiment in which a heating means is provided on a lid.

FIG. 6 is a view showing another embodiment of the lid.

FIG. 7 is a view showing another embodiment of the lid.

FIG. 8 is a diagram showing another embodiment of the lid.

FIG. 9 is a view showing another embodiment of the lid.

FIG. 10 is a diagram showing a conventional magnetic recording medium manufacturing apparatus.

FIG. 11 is a diagram showing a conventional magnetic recording medium manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum vapor deposition apparatus 2 Vacuum tank 3 Base film 4 Cooling can 5 Delivery axis 6 Winding axis 7 Partition plate 8 Winding chamber 9 Deposition chamber 10 Magnetic material 11 Evaporation source 11a Refractory crucible 12 High frequency induction heating coil 13,14 Mask 15 Vapor diffusion control means 16 Second gas blowing part 17 First gas blowing part 18 Mask opening 25 Shutter means 30 Lid 31 Opening / closing means 32 Arm

Claims (1)

[Claims] 1. A transport means for transporting a long flexible substrate in a vacuum atmosphere, an evaporation source made of a magnetic material disposed below which the substrate is transported, and heating and evaporating the evaporation source. Evaporating means, and a cylindrical vapor flow diffusion control means disposed between the evaporating means and the flexible substrate, for regulating and controlling the diffusion direction of the vapor flow heated and evaporated by the evaporating means,
An apparatus for manufacturing a magnetic recording medium for forming a magnetic thin film on the flexible substrate, comprising: an incident angle restricting unit for restricting an incident angle of the vapor flow to the flexible substrate. An apparatus for manufacturing a magnetic recording medium, wherein an openable / closable lid is provided at an opening of the flow diffusion control means on a side facing the flexible substrate.