JP2000339675A - Magnetic tape manufacturing method and magnetic tape manufacturing apparatus - Google Patents

Abstract

(57) [Problem] To reduce cupping and two wrinkles generated when a metal magnetic thin film is formed on a base film. SOLUTION: While moving a strip-shaped base film along a peripheral surface of a cooling can roll in a vacuum chamber, a metal magnetic material in a crucible installed below the cooling can roll is evaporated to form one of the base films 8. After the metal magnetic thin film Mag is formed on the surface 8a of the base film 8, the other surface 8b opposite to the one surface 8a of the base film 8 in a vacuum (in the vacuum chamber 2).
And a method for manufacturing a magnetic tape, comprising irradiating a magnetic tape with a low-power electron beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape manufacturing method and a magnetic tape manufacturing apparatus.

[0002]

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

FIG. 4 is a block diagram showing the structure of a general thin film magnetic tape manufacturing evaporation apparatus to which the oblique evaporation method is applied.
FIG. 6 is a perspective view showing the vicinity of a cooling can roll in a general thin film magnetic tape manufacturing vapor deposition apparatus. FIG. 6 is a diagram illustrating a general thin film magnetic tape manufacturing vapor deposition apparatus in which a metal magnetic thin film is formed on a base film by vapor deposition. FIG. 7 is a thermal analysis result diagram showing the temperature with respect to the film position at the time. FIG. 7 shows the cupping and two wrinkles generated when a metal magnetic thin film is formed on a base film by evaporation using a general thin film magnetic tape manufacturing evaporation apparatus. It is a figure for explaining.

As shown in FIG. 4, a vacuum chamber 2 of a general thin film magnetic tape manufacturing evaporation apparatus (hereinafter, referred to as an apparatus) 1 to which an oblique evaporation method is applied is kept in a vacuum state. In this vacuum chamber 2, a supply roll 3, a take-up roll 4, guide rolls 5, 6, and a cooling can roll 7 are rotatably arranged.

[0005] In the vacuum chamber 2, the strip-shaped base film 8 wound around the supply roll 3 is moved along the guide roll 5 on the supply side, the peripheral surface of the cooling can roll 7, and the guide roll 5 on the winding side. It is running in the direction of the arrow toward the winding roll 4.

Here, the base film 8 uses a polyethylene terephthalate (PET) film.
A roll of tens of thousands of meters is set in the vacuum chamber 2, and a metal magnetic material 10 evaporated from a crucible 9, which will be described below, provided below the cooling can roll 7 on one surface of the base film 8, is continuously deposited in one roll. The method of doing is generally taken.

That is, a crucible 9 formed in a box shape using MgO (magnesia) as a crucible material is installed diagonally below the cooling can roll 7. This crucible 9
Inside, a ferromagnetic material such as Co or CoNi (hereinafter, referred to as a metal magnetic material) 10 is accommodated.

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 pierce-type electron gun 11, an electron beam 12 is emitted toward a metal magnetic material 10 in a crucible 9, and the metal magnetic material 10
Is melted and evaporated to one surface side of the base film 8.

An incident angle regulating mask member 13 is mounted along the cooling can roll 7 toward the crucible 9, and the incident angle regulating mask member 13 is deposited from the crucible 9 when the base film 8 runs. The maximum incident angle θmax and the minimum incident angle θmin of the metal magnetic material 10 with respect to the base film 8 are regulated.

A nozzle 14 is mounted inside the incident angle regulating mask member 13 on the side of the minimum incident angle θmin, and oxygen is emitted from the nozzle 14 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. Accordingly, by scanning the crucible 9 with the electron beam 12 in the longitudinal direction, the metal magnetic material 10 such as Co or CoNi is scanned in the width direction of the base film 8 and is evaporated in the width direction of the base film 8 such as CoO or CoNiO. By repeating this in the longitudinal direction of the base film 8, a long thin magnetic tape 8 is formed on the take-up roll 4.
Winded up to the side.

Here, when the metal magnetic material 10 evaporated from the crucible 9 is formed on the base film 8, it is rotated in the direction of the arrow as shown in FIG. A cooler (not shown) is installed inside the cooling can roll 7 to be formed, and a base film 8 is formed at the time of vapor deposition.
Deformation due to temperature rise is suppressed. In such an oblique deposition method, the edge of the base film 8 is made to have an incident angle regulating mask member so that the metal magnetic material 10 from the crucible 9 does not adhere to the peripheral surface of the cooled rotatable cooling can roll 7. The opening dimension of the incident angle regulating mask member 13 in the width direction is set to be smaller than the width dimension of the base film 8.

[0013]

A metal magnetic material 10 such as Co or CoNi evaporated from a crucible 9 is used as a base film using a general thin film magnetic tape manufacturing evaporation apparatus 1 to which the oblique evaporation method is applied. When a thin metal magnetic thin film is formed on the base film 8, the base film 8 is cooled by the cooling can roll 7 while the base film 8 is being formed along the peripheral surface of the cooling can roll 7, as shown in FIG. In addition, when the metal magnetic material 10 is deposited, the base film 8 is suddenly subjected to a thermal load to form a metal magnetic thin film, and the internal stress of the metal magnetic thin film is also applied.
Only the outermost surface on the side where the metal magnetic thin film is formed undergoes rapid thermal contraction.

In particular, the thermal shrinkage in the film width direction where no tension is applied during running of the base film 8 is large, and as shown in FIGS. 7 (a) and 7 (b), the metal magnetic thin film side is warped inward and the base film 8 is warped inward. Cupping occurs. Then, after forming a metal magnetic thin film on the base film 8, a protective film layer, a lubricating layer, a back coat layer and the like are formed,
When the completed base film 8 is cut into a predetermined width by a slitter and formed into a magnetic tape, the amount of cupping (warpage in the tape width direction) is large. On this occasion,
In order to obtain good electromagnetic conversion characteristics with stable head touch on a thin film magnetic tape, it was necessary to suppress the amount of cupping generated during vapor deposition to within a certain value.

Further, in a recent vapor-deposited magnetic recording tape (ME tape), a step of forming a protective film layer, a lubricating layer, a back coat layer and the like after forming a metal magnetic thin film is provided as a post-process.
Even in the post-process until the tape is cut into a magnetic tape, the thermal shrinkage of the outermost surface in the film width direction is released with time and moves, so that as shown in FIG. This wrinkle occurred, and had a great adverse effect on the runnability and film thickness distribution in the post-process. As a result, the yield was considerably reduced.

In order to solve these problems, a metal magnetic thin film is formed on the base film 8, and then the base film 8 is brought into close contact with a heating roll so that the temperature of the base film 8 exceeds the glass transition point Tg. A method of heat treatment (annealing) is disclosed in JP-A-6-295435. However, in this method, bumps caused by the surface of the base film 8 and the surface of the heating roll running in close contact with each other (for example, foreign matter such as air bubble marks due to rapid expansion of a sealed gas, dusts interposed therebetween, and roll surface projections). (Enlarged marks). These bumps could cause microcracks in the metal magnetic thin film, which caused dropouts. In addition, in order to obtain good electromagnetic conversion characteristics with stable head touch, uniform and fine tape surface roughness is required, and it is necessary to suppress the occurrence of these uneven bumps.

Therefore, there is a demand for a magnetic tape manufacturing method and a magnetic tape manufacturing apparatus for the purpose of preventing the occurrence of wrinkles and reducing the amount of cupping while suppressing the occurrence of bumps.

[0018]

Means for Solving the Problems The present invention has been made in view of the above problems, and a first invention is to make a belt-like base film run in a vacuum chamber along the peripheral surface of a cooling can roll. After evaporating a metal magnetic material in a crucible installed below the cooling can roll to form a metal magnetic thin film on one surface of the base film, the metal magnetic thin film is opposite to one surface of the base film in a vacuum. And irradiating the other surface on the side with a low-power electron beam.

In the second invention, the metal magnetic material in the crucible installed under the cooling can roll is evaporated while running the strip-shaped base film along the peripheral surface of the cooling can roll in the vacuum chamber. Means for forming a metal magnetic thin film on one surface of the base film; and forming the metal magnetic thin film on the other surface opposite to the one surface of the base film in vacuum after forming the metal magnetic thin film. Means for irradiating a power electron beam.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a magnetic tape and an apparatus for manufacturing a magnetic tape according to the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a view showing a state in which a metal magnetic thin film is formed on a base film, FIG. 2 is a view for explaining a magnetic tape manufacturing method and a magnetic tape manufacturing apparatus according to the present invention, and FIG. FIG. 3 is a diagram showing experimental conditions of Experiments 1 to 8 and experimental results of Experiments 1 to 8 in the method of manufacturing a magnetic tape according to the present invention.

For convenience of explanation, the same reference numerals are given to constituent members having the same functions as those of the constituent members described in the conventional example, and the same reference numerals are used, and new reference numerals are given to constituent members different from the conventional example. In addition, this embodiment will be described focusing on points different from the conventional example.

In the magnetic tape manufacturing method and the magnetic tape manufacturing apparatus according to the present invention, immediately after the metal magnetic thin film is formed on one surface of the base film in the vacuum chamber, one of the base films is formed in the vacuum chamber. The other surface opposite to the surface is irradiated with a low-power electron beam from a low-power electron gun.

Therefore, the magnetic tape manufacturing apparatus 20 according to the present invention remodels the inside of the vacuum chamber 2 of the general thin film magnetic tape manufacturing vapor deposition apparatus 1 described above with reference to FIG. Side walls 2b and 2c are provided on the take-up side to divide into two parts, a vapor deposition side and a low-power electron beam irradiation side, and are newly added to the low-power electron beam irradiation side, and are illustrated downstream by a guide roll 6 on the take-up side. Guide roll 21 to the left, small-diameter rotatable cooling can roll 22, guide roll 2
3, 24, and a winding roll 25 are arranged in this order, and the side wall 2d of the vacuum chamber 2 is opposed to the small diameter cooling can roll 22.
A low-power electron gun 26 is mounted on the base film 8 and a deflection magnet 2 for scanning a low-power electron beam 27 around the low-power electron gun 26 in the width direction of the base film 8.
8 is installed.

First, as shown in FIG. 2, when the metal magnetic thin film Mag is formed on one surface 8a of the base film 8 using the magnetic tape manufacturing apparatus 20 according to the present invention, a cooling can is performed. The diameter of the roll 7 is 1000 mm, the width of the cooling can roll 7 is 600 mm, the width of the base film 8 is 560 mm, the width of the metal magnetic thin film Mag formed on the base film 8 is 540 mm, and the width of the crucible 9 is 7 mm.
00 mm, metal magnetic material (pure cobalt C) in crucible 9
o) For melting and vapor deposition of 10, a 90 ° deflection piercing electron gun 11 having an output of 300 kW was used. The incident angle regulating mask member 13 is made of stainless steel having a thickness of 15 mm and surrounds the outer periphery of the film forming area while being cooled with water. In the vicinity of the crucible 9, an electron beam 12 emitted from a pierce type electron gun 11 is provided.
The deflection magnet 16 required for proper incidence of the light was installed.
Further, a feeder (not shown) was provided so that a constant amount of the metallic magnetic material (pure cobalt Co) 10 was continuously supplied from one end of the crucible 9.

Here, the metal magnetic material 10 in the crucible 9 installed below the cooling can roll 8 is evaporated while the strip-shaped base film 8 runs along the peripheral surface of the cooling can roll 7 in the vacuum chamber 2. When the metal magnetic thin film Mag is formed on one surface 8a of the strip-shaped base film 8, the minimum incident angle θmi of the incident angle regulating mask member 13 is formed.
While introducing 1800 ccm of oxygen gas from the n-side and controlling the film thickness of the metal magnetic thin film (CoO film) to 0.18 μm with a transmission and reflection type film thickness monitor, 6.4 μm PE
On one surface 8a of a base film 8 made of T (polyethylene terephthalate), a CoO film is formed in a length of about 5000 m in a longitudinal direction.

Thereafter, when the base film 8 on which the metal magnetic thin film Mag is formed reaches the small diameter cooling can roll 22 through the guide roll 6 on the winding side and the guide roll 21 in this order, one surface 8a of the base film 8 is formed. Is made to adhere and run along the peripheral surface of the cooling can roll 22 which is rotatable in the direction of the arrow. Here, the cooling can roll 22 is formed on the other surface 8b (FIG. 1) of the base film 8 where the metal magnetic thin film Mag is not formed. A low-power electron beam 27 from a low-power electron gun 26 facing the laser beam is radiated while being scanned in the width direction of the base film 8 by a deflection magnet 28, and the other surface 8 is irradiated.
b is heated to an appropriate temperature by the low-power electron beam 27, and the base film 8 is wound on a winding roll 25 via guide rolls 23 and 24.

Next, the magnetic tape manufacturing apparatus 20 described above is used.
After the following experiment was performed using, the presence or absence of bumps, the state of generation of two wrinkles shown in FIG. 7C, and the state of heat loss of the base film were observed. Also, base film 8
Was cut to a width of 6.35 mm by a slitter, and FIG.
The cupping amounts shown in (a) and (b) were measured. Positive (+) when the metal magnetic thin film surface side on the base film 8 was concavely cupped, and negative (-) when convexly cupped.

Under the experimental conditions shown in FIG. 3, one surface 8a of the base film 8 is formed on the one surface 8a of the base film 8 using the general vapor deposition apparatus 1 for manufacturing a thin film magnetic tape described above with reference to FIG.
g was formed as a comparative example (Experiment 1), and the base film 8 was formed using the magnetic tape manufacturing apparatus 20 according to the present invention.
After the metal magnetic thin film Mag is formed on one surface 8a, the low power electron gun 26 is formed on the other surface (the surface opposite to the one surface) 8b where the metal magnetic thin film Mag is not formed on the base film 8. The present invention relates to the case where the beam power of the low-power electron beam 27 from the laser beam is varied (Experiments 2 to 8).
And

<Experiment 1 (Comparative Example)> Using the general vapor deposition apparatus 1 for manufacturing a thin film magnetic tape described above with reference to FIG.
While controlling with a transmission and reflection type film thickness monitor to be 8 μm, a processing length of 500 is applied to one surface 8 a of the base film 8 of 6.4 μm PET (polyethylene terephthalate).
A film of 0 m was formed and wound into a roll.

<Experiment 2 (Invention)> Using a magnetic tape manufacturing apparatus 20 according to the present invention, a CoO film was formed on one surface 8a of the base film 8 under the same conditions as in Experiment 1 above by 5000.
After the film is formed, a low-power electron beam 27 from a low-power electron gun 26 installed in advance before winding into a roll is applied to the other surface 8b of the base film 8 as shown in FIG. A low power electron beam 27 was irradiated while scanning in the full width direction of the film while the beam diameter of the beam 27 was maximized, and then the film was wound into a roll. The power of the low power electron beam 27 was 1 kW.

<Experiment 3 (invention)> Under the same conditions as Experiment 2, only the power of the low power electron beam 27 was set to 2 kW.

<Experiment 4 (invention)> Under the same conditions as Experiment 2, only the power of the low power electron beam 27 was set to 4 kW.

<Experiment 5 (invention)> Under the same conditions as Experiment 2, only the power of the low power electron beam 27 was set to 6 kW.

<Experiment 6 (invention)> Under the same conditions as Experiment 2, only the power of the low power electron beam 27 was set to 8 kW.

<Experiment 7 (invention)> Under the same conditions as in Experiment 2, only the power of the low-power electron beam 27 was set to 10 kW.

<Experiment 8 (invention)> Under the same conditions as Experiment 2, only the power of the low power electron beam 27 was set to 15 kW.

Next, the experimental results of Experiments 1 to 8 will be described with reference to FIG.

As shown in FIG. 3, for the comparative examples of Experiment 1, and the present inventions of Experiments 2 to 8, the occurrence of bumps, the occurrence of wrinkles, the loss of heat, and the amount of cupping were observed and evaluated. At this time, the amount of cupping is set at an arbitrary point inside the two wrinkles (the same
(For 0 channel) respectively.

As is evident from the experimental results shown in FIG. 3, the metal magnetic thin film M
When the other surface 8b on which the metal magnetic thin film Mag is not formed is irradiated with an appropriate low-power electron beam 27 while scanning in the width direction of the base film 8 after the formation of the ag, two wrinkles occur. It was found that the amount of cupping could be significantly reduced and the amount of cupping could be significantly reduced. That is, the base film 8
When the metal magnetic material 10 is vapor-deposited on one surface 8a of the base film 8, a heat load is applied to the one surface 8a, thereby causing cupping and two wrinkles. However, low power is applied to the other surface 8b of the base film 8. By irradiating the electron beam 27 and heating the other surface 8b to an appropriate temperature with the low-power electron beam 27, reverse correction is performed with respect to vapor deposition, so that the amount of cupping and two wrinkles can be offset.

In the above embodiment, the step of forming the metal magnetic thin film Mag on one surface 8a of the base film 8 and the step of irradiating the other surface 8b of the base film 8 with the low power electron beam 27 are described. The metal magnetic thin film Mag was formed on the base film 8 by the general thin film magnetic tape manufacturing vapor deposition apparatus 1 shown in FIG. The take-up roll 4 may be taken out of the vacuum chamber 2 and the other surface 8b of the base film 8 may be irradiated with the low-power electron beam 27 in another vacuum chamber.

[0042]

According to the method for manufacturing a magnetic tape and the apparatus for manufacturing a magnetic tape according to the present invention described in detail above, in particular,
After the metal magnetic thin film is formed on one surface of the base film, the other surface opposite to the one surface of the base film is irradiated with a low-power electron beam in a vacuum, so there is no bump generation, and (2) The occurrence of wrinkles can be prevented and the amount of cupping can be significantly reduced, and a good magnetic tape having stable electromagnetic conversion characteristics can be obtained. This ultimately improves the product yield of the magnetic tape and greatly reduces the cost of the product.

[Brief description of the drawings]

FIG. 1 is a view showing a state in which a metal magnetic thin film is formed on a base film.

FIG. 2 is a diagram for explaining a magnetic tape manufacturing method and a magnetic tape manufacturing apparatus according to the present invention.

FIG. 3 shows a method of manufacturing a magnetic tape according to the present invention.
It is the figure which showed the experiment conditions of experiment 1-8, and the experiment result of experiment 1-8.

FIG. 4 is a configuration diagram showing a configuration of a general thin film magnetic tape manufacturing evaporation apparatus to which an oblique evaporation method is applied.

FIG. 5 is a perspective view showing the vicinity of a cooling can roll in a general vapor deposition apparatus for manufacturing a thin film magnetic tape.

FIG. 6 is a thermal analysis result showing a temperature with respect to a film position when a metal magnetic thin film is formed on a base film by vapor deposition using a general vapor deposition apparatus for manufacturing a thin film magnetic tape.

FIG. 7 is a diagram for explaining cupping and two wrinkles generated when a metal magnetic thin film is formed on a base film by vapor deposition using a general vapor deposition apparatus for manufacturing a thin film magnetic tape.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... General vapor deposition apparatus for thin-film magnetic tape manufacture, 2 ... Vacuum tank, 7 ... Cooling roll, 8 ... Base film, 8a
.. One surface, 8b the other surface, 9 a crucible, 10 a metal magnetic material, 11 a pierce type electron gun, 12 an electron beam,
13: Incident angle regulating mask member, 20: Magnetic tape manufacturing apparatus according to the present invention, 26: Low power electron gun, 27: Low power electron beam, Mag: Metal magnetic thin film.

Claims (2)

[Claims] 1. A metal film material in a crucible installed under a cooling can roll is evaporated while a strip-shaped base film is moved along a peripheral surface of a cooling can roll in a vacuum chamber, thereby evaporating the base film. Forming a metal magnetic thin film on one surface of the base film, and irradiating the other surface of the base film opposite to the one surface with a low power electron beam in a vacuum. 2. A method according to claim 1, wherein the step of moving the strip-shaped base film along the peripheral surface of the cooling can roll in a vacuum chamber evaporates a metal magnetic material in a crucible provided below the cooling can roll, thereby forming the base film. Means for forming a metal magnetic thin film on one surface of the base film; and, after forming the metal magnetic thin film, irradiating a low-power electron beam to the other surface opposite to the one surface of the base film in a vacuum. And a means for manufacturing a magnetic tape.