JP2001236642A - Vapor deposition device for thin film magnetic tape and method for manufacturing thin film magnetic tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the yield of a product and the utilization efficiency of a vapor deposition material when a metal magnetic thin film is formed on a base film. SOLUTION: In a vapor deposition device 1B for thin film magnetic tape wherein the belt-like base film 8 runs along the peripheral surface of a cooling can roll 7 in vacuum vessel 1, a metal magnetic material 10 melted in a crucible 9 provided below the cooling can roll 7 is vaporized, the metal magnetic material 10 vaporized is introduced to the cooling can roll 7 side while an incident angle regulating mask member 13 provided above the crucible 9 is regulated and an oxygen gas is blown to the metal magnetic material vaporized and passed through the incident angle regulating mask member 13 from an oxygen gas introducing pipe 14 provided between the lower side of the cooling can roll 7 and the incident angel regulating mask member 13 to form the metal magnetic thin film on one surface of the base film 8, an oxygen gas heating means 17 for heating the oxygen gas introducing pipe 14 or the oxygen gas itself is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, thin-film magnetic tapes, perpendicular magnetic tapes, and the like 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 evaporation apparatus to which the oblique evaporation method is applied. FIG. 5 is provided below a cooling can roll in a general thin film magnetic tape evaporation apparatus. It is the perspective view which showed the oxygen gas introduction pipe which was shown.

As shown in FIG. 4, a vacuum chamber 2 of a general thin film magnetic tape evaporation apparatus 1A to which the 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] Then, 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 6 on the winding side. It is running in the direction of the arrow toward the winding roll 4.

Here, the base film 8 is made of a polyethylene terephthalate (PET) film or the like. The metal magnetic material 10 evaporated from a crucible 9, which is set and placed on one surface of the base film 8 below the cooling can roll 7, which will be described later.
Is generally performed by one-roll evaporation.

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 pierce-type electron gun 11 for melting the metal magnetic material 10 housed therein and evaporating the molten metal magnetic material 10 from the opening of the crucible 9 is attached. In the pierce-type electron gun 11, an electron beam 12 is emitted toward the metal magnetic material 10 in the crucible 9, and the metal magnetic material 10 is melted and vaporized on one side of the base film 8.

An incident angle regulating mask member 13 is mounted along the lower portion of the cooling can roll 7 so as to face the crucible 9 side.
Regulates the maximum incident angle θmax and the minimum incident angle θmin of the metallic magnetic material 10 deposited from the crucible 9 with respect to the base film 8 when the base film 8 travels along the cooling can roll 7.

An oxygen gas introduction pipe 14 is mounted along the lower part of the cooling can roll 7 and inside the incident angle regulating mask member 13 on the side of the minimum incident angle θmin. This oxygen gas introduction pipe 14 is shown in FIG.
As shown in an enlarged manner, a straight pipe having one oxygen gas inlet is welded at a substantially central portion of the loop pipe, and the loop pipe of the oxygen gas inlet pipe 14 is used as the loop pipe. A plurality of fine holes 14a for blowing out oxygen gas are formed along the film formation range where the metal magnetic thin film is formed in the width direction of the base film 8. The oxygen gas introduced into the oxygen gas introduction pipe 14 wraps around the left and right sides of the loop pipe and is blown out toward the metal magnetic material 10 deposited from the plurality of fine holes 14a. It is the mainstream that the magnetic material 10 is oxidized to ensure the improvement of the magnetostatic property and the reliability (durability and corrosion resistance) of the metal magnetic thin film described later.

Referring back to FIG. 4, 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. Have been. 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 length direction of the base film 8, a long thin film magnetic tape is wound up on the take-up roll 4 side.

Here, when forming the metal magnetic material 10 evaporated from the crucible 9 on the base film 8 as a metal magnetic thin film, a cooling can roll rotating in the direction of the arrow in consideration of heat resistance to the base film 8. A cooler (not shown) is provided inside 7 to suppress deformation of the base film 8 due to a rise in temperature during vapor deposition. 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]

By using a general thin film magnetic tape evaporation apparatus 1A to which the oblique evaporation method is applied, a metal magnetic material 10 such as Co or CoNi evaporated from a crucible 9 is used as a base film 8. When a metal magnetic thin film is formed thereon, the mask opening of the incident angle restricting mask member 13 is considerably narrow as described above, so that the evaporated metal magnetic material (evaporated metal magnetic material) 10
The efficiency of use was about 10 to 15%, and most of the remaining was undesired deposits. For this reason, it is necessary to further improve the magnetostatic properties in order to widen the mask opening of the incident angle regulating mask member 13 to the minimum incident angle side even slightly and to improve the utilization efficiency of the evaporated metal magnetic material.

Further, in the oblique deposition method, the incident angle of the vaporized flying particles on one surface of the base film 8 substantially determines various characteristics. In particular, the dispersion and distribution of the incident angle of the initial growth layer of the metal magnetic thin film. Has had a great influence on the characteristic distribution of the metal magnetic thin film in the width direction of the base film 8. In particular, the metal magnetic material 10 in which oxygen gas is vapor-deposited from a plurality of fine holes 14a formed in the oxygen gas introduction pipe 14
When using oxygen gas at about normal temperature when spraying toward the surface, the molecules of the oxygen gas are not actively mobilized, so that the bonding with the evaporated metal magnetic material such as Co is not performed well. Has occurred. For this reason, after the metal magnetic thin film is formed, the yield of non-defective thin film magnetic tapes is low, and in order to ensure quality safety, it is necessary to manufacture thicker film in consideration of the distribution and variation of the magnetostatic characteristics. This has led to an increase in manufacturing costs due to a further decrease in the use efficiency of the deposited metal magnetic material.

[0015]

Means for Solving the Problems The present invention has been made in view of the above problems, and a first invention is to run a strip-shaped base film in a vacuum chamber along a peripheral surface of a cooling can roll, In addition, the metal magnetic material melted in the crucible provided below the cooling can roll is evaporated, and the evaporated metal magnetic material is regulated by the incident angle regulating mask member provided above the crucible, and the cooling can roll is formed. While guiding to the side, oxygen gas is blown from the oxygen gas introduction pipe provided between the lower portion of the cooling can roll and the incident angle regulating mask member onto the evaporated metal magnetic material passing through the incident angle regulating mask member, In a vapor deposition device for a thin film magnetic tape for forming a metal magnetic thin film on one surface of the base film, the oxygen gas introduction pipe or the oxygen gas itself is added. It is an evaporation apparatus for a thin film magnetic tape characterized by comprising an oxygen gas heating means for.

According to a second aspect of the present invention, there is provided a method for moving a strip-shaped base film along a peripheral surface of a cooling can roll in a vacuum chamber and melting the metal in a crucible installed below the cooling can roll. The magnetic material is evaporated, and the evaporated metal magnetic material is guided to the cooling can roll side while being regulated by the incident angle regulating mask member provided above the crucible. A thin film magnetic tape for spraying an oxygen gas from an oxygen gas introduction pipe provided between the metal film and the evaporated metal magnetic material passing through the incident angle regulating mask member to form a metal magnetic thin film on one surface of the base film. Wherein the oxygen gas heated from the oxygen gas introduction pipe is sprayed on the evaporated metal magnetic material. It is a method of manufacture.

[0017]

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

FIG. 1 is a structural view showing the structure of a thin film magnetic tape vapor deposition apparatus according to the present invention, and FIG. 2 is an oxygen gas introduction provided below a cooling can roll in the thin film magnetic tape vapor deposition apparatus according to the present invention. FIG. 3 is a perspective view showing the pipe, and FIG. 3 is a view showing the relationship between the heating temperature of the oxygen gas introduction pipe and the magnetostatic property.

For convenience of explanation, components having the same functions as the components described in the prior art are denoted by the same reference numerals and will be described as appropriate, and new components will be assigned to components different from those in the conventional example. In addition, this embodiment will be described focusing on points different from the conventional example.

As shown in FIG. 1, in the thin film magnetic tape evaporation apparatus 1B according to the present invention, a metal magnetic thin film is formed on one surface of the base film 8 in the vacuum chamber 2 by applying an oblique evaporation method. In order to heat the oxygen gas to the oxygen gas introduction pipe 14 provided below the cooling can roll in the vacuum chamber 2 of the general thin film magnetic tape deposition apparatus 1A described with reference to FIG. Attach oxygen gas heating means 17,
It is characterized in that the oxygen gas introduced into the oxygen gas introduction pipe 14 is blown onto the evaporated metal magnetic material 10 while heating.

Here, as shown in FIG. 2 in an enlarged manner, the oxygen gas introduction pipe 14 is formed by connecting a straight pipe having one oxygen gas introduction port to substantially the center of the loop pipe in the same manner as described above. In the loop-shaped pipe of the oxygen gas introduction pipe 14, micro holes 14a for blowing out oxygen gas are formed along the film forming range where the metal magnetic thin film is formed in the width direction of the base film 8. Are formed. Further, the heating wire (Nichrome wire) 17 for the oxygen gas heating means is wound around the oxygen gas introduction pipe 14 except for a part of the plurality of fine holes 14a for blowing. Then, an electric current is caused to flow through the nichrome wire 17 serving as an oxygen gas heating means, whereby the oxygen gas introduction pipe 14 is heated, and the heated oxygen gas flows through the plurality of fine holes 14a into the metal magnetic material 10.
It is blowing out towards.

The outline of the vapor deposition device 1B for a thin film magnetic tape described above is as follows. The diameter of the cooling can roll 7 is 1000 mm, the width of the cooling can roll 7 is 300 mm,
The width of the base film 8 is 280 mm,
The ferromagnetic material (pure Co) in the crucible 9 using a ceramic (MgO) was melted and vapor-deposited using a 90 ° deflection pierce-type electron gun 11 with an output of 100 kW. The incident angle regulating mask member 13 is made of stainless steel having a thickness of 10 mm and surrounds the outer periphery of the film forming area. In addition, crucible 9
A deflection magnet 16 (FIG. 5) required for proper incidence of the electron beam was installed in the vicinity of. Further, a feeder (not shown) was provided so that a constant amount of ferromagnetic material (pure Co) was continuously supplied from one end of the crucible 9. The following experiment was performed using this apparatus 1B.

[Experiment 1] As shown in FIG. 2, the oxygen gas introducing pipe 14 is a loop pipe using a stainless steel pipe of φ 1/4 ”with fine holes 14a for blowing out oxygen gas of φ 0.5 mm having a pitch of 3 mm. In order to heat the oxygen gas introduced into the oxygen gas introduction pipe 14, a plurality of fine holes 14a for blowing out oxygen gas were used.
A nichrome wire 17 for heating oxygen gas was wound around a portion other than the portion, and the temperature of this pipe could be adjusted by a temperature controller using a thermocouple.

The oxygen gas introduction pipe 14 is set so that the plurality of micro holes 14a are parallel to the vapor flow incident portion in the width direction of the base film 8, and the heating temperature of the oxygen gas introduction pipe 14 is set to room temperature. About 20 ° C (without heating)
The temperature was changed stepwise to 500 ° C., and a total of 10 temperatures were set, and the amount of oxygen gas introduced from the minimum incident angle side was 900 cc.
The thickness of the CoO film was controlled to be 0.16 μm by a transmission type film thickness monitor, and a processing length of 100 m was formed.

The heating temperature of the oxygen gas introduction pipe 14 is set to 10
Sampling was performed from a roll of 100 m each formed in a different manner, and a part of the CoO film was etched with dilute nitric acid. .16 μm.

Thereafter, the magnetostatic properties of the remaining unetched portions of each sample were measured by a vibrating magnetometer (VSM). The result is shown in FIG. Hc is the coercive force, M
s indicates the saturation magnetization, and Rs indicates the squareness ratio.

As is apparent from FIG. 3, when the oxygen gas temperature is in the range of 0 ° C. to 30 ° C., the oxygen gas temperature is at room temperature, which is the state of the prior art. In this case, the coercive force Hc and the squareness ratio R
s is depressed. On the other hand, when the oxygen gas introduction pipe 14 is heated, the heating temperature of the oxygen gas introduction pipe 14 is 100 ° C. despite the fact that there is no change in the saturation magnetization Ms.
As described above, it was found that the coercive force Hc and the squareness ratio Rs were significantly improved, and exhibited good values. The reason for this is that when the oxygen gas is heated, the motion of the oxygen gas molecules becomes active and the kinetic energy increases, so that the oxygen gas easily bonds to the atoms of the evaporated metal magnetic material such as Co, and in particular, the coercive force Hc increases. The correlation between the temperature and the temperature of oxygen gas is remarkable.

[Experiment 2] φ of oxygen gas introduction pipe 14
The same experiment as in Experiment 1 was carried out under the same conditions except that the pitch of the fine holes 14a for blowing oxygen gas of 0.5 mm was changed to 5 mm, and almost the same results as in Experiment 1 were obtained.

[Experiment 3] φ of oxygen gas introduction pipe 14
The same experiment was performed under the same conditions as in Experiment 1 except that the pitch of the fine holes 14a for blowing oxygen gas of 0.5 mm was changed to 10 mm, and almost the same results as in Experiment 1 were obtained. [Experiment 4] A similar experiment was performed under the same conditions as in Experiment 3 except that the oxygen gas introduction pipe 14 was changed to a に ″ stainless steel tube, and almost the same results as in Experiment 3 were obtained.

In the above experiment, an example was described in which the oxygen gas introduction pipe 14 was heated by the nichrome wire 17 to heat the oxygen gas. However, the oxygen gas heated in advance by another oxygen gas heating means was replaced with the oxygen gas. It goes without saying that the same effect as described above can be obtained even when the heated oxygen gas is introduced into the introduction pipe 14 and sprayed onto the evaporated metal magnetic material from the plurality of fine holes 14a for blowing out the oxygen gas.

[0031]

According to the vapor deposition apparatus for a thin film magnetic tape and the method for manufacturing a thin film magnetic tape according to the present invention described above in detail, the oxygen gas for heating the oxygen gas itself or the oxygen gas itself can be used. Since heating means is provided and oxygen gas heated from an oxygen gas introduction pipe is sprayed on the evaporated metal magnetic material, the magnetostatic properties after forming the metal magnetic thin film on the base film, particularly the coercive force and squareness ratio Is greatly improved. As a result, the yield of the thin film magnetic tape and the utilization efficiency of the evaporated magnetic metal material can be improved, and the thin film magnetic tape can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of a vapor deposition apparatus for a thin film magnetic tape according to the present invention.

FIG. 2 is a perspective view showing an oxygen gas introducing pipe provided below a cooling can roll in the thin film magnetic tape vapor deposition apparatus according to the present invention.

FIG. 3 is a diagram illustrating a relationship between an oxygen gas introduction pipe heating temperature and magnetostatic characteristics.

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

FIG. 5 is a perspective view showing an oxygen gas introduction pipe provided below a cooling can roll in a general thin film magnetic tape deposition apparatus.

[Explanation of symbols]

1B: Vapor deposition device for thin-film magnetic tape according to the present invention, 2: vacuum tank, 7: cooling can roll, 8: base film, 9
... Crucible, 10 ... Metal magnetic material, 11 ... Pierce type electron gun, 12 ... Electron beam, 13 ... Mask member for restricting incident angle,
14 ... oxygen gas introduction pipe, 14a ... micropore, 17 ... oxygen gas heating means (Nichrome wire).

Claims (2)

[Claims] 1. A belt-shaped base film is moved along a peripheral surface of a cooling can roll in a vacuum chamber, and a metal magnetic material melted in a crucible installed below the cooling can roll is evaporated. The evaporating metal magnetic material is guided to the cooling can roll side while being regulated by the incident angle regulating mask member provided above the crucible, and provided between the lower portion of the cooling can roll and the incident angle regulating mask member. An evaporation apparatus for a thin film magnetic tape for spraying an oxygen gas from an oxygen gas introduction pipe onto the evaporated metal magnetic material passing through the incident angle control mask member to form a metal magnetic thin film on one surface of the base film, An evaporation apparatus for a thin-film magnetic tape, comprising an oxygen gas introduction pipe or an oxygen gas heating means for heating the oxygen gas itself. 2. A strip-shaped base film is run along a peripheral surface of a cooling can roll in a vacuum chamber, and a metal magnetic material melted in a crucible installed below the cooling can roll is evaporated. The evaporating metal magnetic material is guided to the cooling can roll side while being regulated by the incident angle regulating mask member provided above the crucible, and provided between the lower portion of the cooling can roll and the incident angle regulating mask member. A method of manufacturing a thin-film magnetic tape, wherein oxygen gas is blown from an oxygen gas introduction pipe onto the evaporated metal magnetic material passing through the incident angle control mask member to form a metal magnetic thin film on one surface of the base film, A method for manufacturing a thin-film magnetic tape, comprising blowing the oxygen gas heated from an oxygen gas introduction pipe onto the evaporated metal magnetic material.