JPH07109570A - Vacuum deposition device and production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To form the thin film of a ferromagnetic metal excellent in electromagnetic conversion characteristic with high vapor deposition efficiency by providing plural rotary drums to one vaporization source and specifying the angle between the center axis of each drum and horizontal. CONSTITUTION:Plural rotary drums 3 and 4 are provided in a vacuum deposition device. A metal vapor current is vaporized from one vaporization source toward the drums 3 and 4 and continuously laminated and deposited on a substrate such as a polymer film 1. The angle between the center axes of the drums 3 and 4 and horizontal is controlled to 0-75 deg.. A magnetic recording medium excellent in electromagnetic conversion characteristic and magnetic characteristic is mass-produced in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum vapor deposition apparatus excellent in mass productivity and a method for manufacturing a metal thin film type magnetic recording medium of high recording density using the apparatus. It covers a wide range of fields such as information equipment.

[0002]

2. Description of the Related Art In recent years, the technical development of magnetic recording media has been remarkable as seen in the improvement of magnetic recording density. Examples of conventional magnetic recording media include audio, iron oxide powder, chrome oxide powder, pure iron powder, etc. used in video tape materials on a polymer film together with an abrasive, a binder such as a resin and the like. There is a coated magnetic recording medium coated.

However, the coercive force of the conventional coating tape is
In order to improve the recording density electromagnetic conversion characteristics, Fe, N are used by vacuum deposition, ion plating, sputtering, etc.
Studies have been made on a metal thin film type magnetic recording medium in which a magnetic metal such as i, Co or Cr alone or an alloy thereof is vapor-deposited on a polymer film. Moreover, a metal thin film type magnetic recording medium for audio and video by the oblique evaporation method has already been put to practical use.

Further, a memory of a computer such as an information device-
The magnetic recording medium for a hard disk used as is a method of depositing aluminum and cobalt oxide on a glass substrate by a sputtering method.

In these memory media, further improvement in recording density and higher image quality will be demanded in the future, and for this reason, a great leap in magnetic characteristics and electromagnetic conversion characteristics of these conventional metal thin film magnetic recording media is expected. ing. However, the biggest drawback of the metal thin film type magnetic recording medium is a problem in mass productivity, and in particular, the improvement of electromagnetic conversion characteristics often leads to a decrease in vapor deposition efficiency.

As a conventional apparatus for manufacturing a metal thin film magnetic recording medium and a method for manufacturing the same, a manufacturing method using a continuous winding vacuum vapor deposition apparatus as shown in FIG. 3 is particularly superior in productivity. , Is very effective as a realistic mass production method. Next, a manufacturing apparatus and a manufacturing method will be described. The polymer film 1 is set on the feed shaft 2, passed through the rotating drum 3, and wound by the winding shaft 5. The magnetic metal 8 in the ceramic crucible 7 is melted and evaporated by the electron gun 10 from below the rotating drum to form it on the polymer film. This time,
The metal vapor flow unnecessary for vapor deposition is masked by the shield plates 11 and 12. Generally, a vapor deposition tape (ME) uses a vapor deposition angle component of about 40 to 90 degrees. The polymer film used for the vapor deposition substrate is polyethylene terephthalate (PE
In T), a magnetic metal thin film layer 1800Å of cobalt oxide is vapor-deposited on the surface by a reactive vapor deposition method with a cooling can of -20 degrees.

[0007]

In the future, there is a growing demand for downsizing and high image quality in video tapes and high recording density in information equipment. On the other hand, in the method of manufacturing a metal thin film type magnetic recording medium using a vacuum vapor deposition machine, as long as the oblique vapor deposition technique is used, the magnetic characteristics and electromagnetic conversion characteristics are improved, and the vapor deposition efficiency is lowered and the productivity is significantly deteriorated.

[0008]

In order to solve this problem, the present invention provides a plurality of rotating drums in a vacuum vapor deposition apparatus,
A single evaporation source evaporates a metal vapor stream on the plurality of rotating drums to successively stack and deposit on a substrate such as a polymer film.

[0009]

A ferromagnetic metal thin film layer is formed on a polymer film by using a vacuum vapor deposition apparatus having a plurality of rotating drums to obtain a metal thin film type magnetic recording medium having excellent magnetic characteristics and electromagnetic conversion characteristics. In particular, the electromagnetic conversion characteristics and the vapor deposition efficiency are greatly improved by continuously laminating the magnetic metal stream by a plurality of rotating drums, and the vapor deposition rate and productivity are also improved.

[0010]

EXAMPLES Examples of the apparatus of the present invention will be described in detail below.

(Embodiment 1) (FIG. 1) is an external view of a vacuum vapor deposition apparatus for producing a metal thin film type vapor deposition tape according to an embodiment of the present invention. The principle of the vapor deposition apparatus is that the polymer film 1 is set on the feed shaft 2 and the rotary drums (cans) 3 and 4 and the intermediate roll are used.
It winds up with the winding shaft 5 through the la 6. The magnetic metal 8 in the ceramic crucible 7 is melted by the electron beam 10 from below. A Co oxide layer is formed on the polymer film 1 by reactive vapor deposition of oxygen gas 9 with a Co vapor flow in an oxygen atmosphere. Co on the surface in a similar manner using reactive evaporation.
Forming an oxide film. The oblique incident angle was set to a high incident angle of 90 degrees and a low incident angle of 40 degrees. The mask 11 cuts off the metal vapor streams that are unnecessary for vapor deposition.
Further, the shielding plate 12 prevents the metal vapor flow from flowing into unnecessary portions during vapor deposition. The rotary drum has a movable structure such that the angle between the center axis between the drums and the horizontal line can be changed from 0 to 90 degrees as shown in FIG. 2, and the mask and the shielding plate can be adjusted accordingly. The examples of the present invention were performed primarily at the 45 degree position.

The polymer substrate used for vapor deposition has a thickness of 10
Using a polyethylene terephthalate (PET) substrate with a thickness of μm, the magnetic layer has a thickness of 600 Å for the first layer and 1200 for the second layer.
Å, total thickness 1800Å. At this time, the average film deposition rate from the electron beam evaporation source was 3000 nm / sec, and the temperature of the rotating drums 3 and 4 was set to -20 degrees. The amount of oxygen introduced was calculated from the theoretical ratio.

(Embodiment 2) In the same vapor deposition apparatus as in (Embodiment 1) of FIG. 1, the relative position of the rotary drum to the horizontal is 45 degrees, the inlet rotary drum is cooling can, and the outlet rotary drum is heating can. For the evaporation on the cooling can side, excess oxygen gas is introduced into the Co metal vapor stream to form a non-magnetic cobalt oxide layer. A cobalt oxide film is formed on the surface thereof by a heating can by a reactive vapor deposition method of cobalt-oxygen gas.
As the vapor deposition incident angle of the oblique vapor deposition, the high incident angle of the first layer is 90 degrees,
Bottom incident angle 20 °, second layer high incident angle 70 °, low incident angle 3
I went to 0 degrees.

A polyethylene naphthalate (PEN) substrate having a thickness of 7 μm is used as the polymer substrate, and the magnetic layers are formed by the first layer having a thickness of 100Å, the second layer having a thickness of 1500Å, and the total thickness of 1600Å.
And At this time, the average film deposition rate from the electron beam evaporation source was 3000 nm / sec, the cooling can temperature during vapor deposition was 20 degrees, and the temperature of the heating can was set to 80 degrees. The amount of oxygen gas was calculated from the theoretical ratio for the first layer and 10 times the theoretical ratio.

(Embodiment 3) In the same vapor deposition apparatus as in (Embodiment 1) of FIG. 1, the relative position of the rotary drum to the horizontal line is 30 degrees as shown in FIG.
A heating can was used as the output rotary drum. The inlet side rotating drum forms the first layer in the Co-Cr metal vapor flow with a high incident angle of 70 degrees, a bottom incident angle of 20 degrees, and a heating temperature of 230 degrees, and the outlet side rotating drum has a mask angle of 60 to 30 degrees. Heating temperature in the range 2
Deposition at 30 degrees.

A polyimide (PI) substrate having a thickness of 10 μm is used as a polymer substrate, and a magnetic layer having a thickness of the first layer 300 is used.
Å, second layer 1500 Å, total thickness 1800 Å. At this time, the average film deposition rate from the electron beam evaporation source is 3000.
nm / sec.

The performance and effect of the metal thin film type magnetic recording medium according to the above embodiment will be described. The evaluation results of the electromagnetic conversion characteristics and the measurement results of the vapor deposition efficiency by the 8 mm deck are shown in (Table 1).

[0018]

[Table 1]

The evaluation method of the metal thin film type magnetic recording medium was set to 8 mm tape after vapor deposition, a commercially available 8 mm video deck was modified into an evaluation device, and electromagnetic conversion characteristics were examined using a metal head. Electromagnetic conversion characteristics include output near recording frequency 7MHZ, C
/ N was evaluated and compared as a relative output with respect to the conventional example. In order to compare the deposition efficiency, it was determined by measuring the weight change of the magnetic metal in the film substrate and the crucible before and after the deposition. Further, the vapor deposition efficiency was obtained from the calculation formula Cos ³ θ and compared with the experimental value.

As a result, the embodiment of the present invention is superior to the conventional example over the entire recording wavelength, and in particular, in the short wavelength region, the C / N is improved by 5 dB or more. When looking at the electromagnetic conversion characteristics of the embodiment of the present invention and the conventional example, the output in the short wavelength region does not change much and the noise is low, and the C / N is improved accordingly. On the other hand, as for the vapor deposition efficiency which is another feature of the present invention, when the vapor deposition conditions are compared with those of Example 1 similar to the conventional example, the vapor deposition efficiency is improved by 1.5 times, which is 1.6 times the theoretical calculated value. Was in agreement. The reason that the vapor deposition efficiency of Example 2 is higher than that of Example 1 is due to the difference in vapor deposition incident angle. However, in comparison with the second and third embodiments, although the third embodiment has a poorer vapor deposition angle in terms of vapor deposition efficiency, the fact that it does not change is that the relative positions of the two rotary drums are located on the bottom angle side. ,
This is because vapor deposition is carried out under the condition of high evaporation rate because of the positional relationship close to the evaporation source.

In the production of the magnetic recording medium of the present invention, when the vapor deposition metal is vapor-deposited from one vaporization source, the vapor-deposited film is continuously formed by two or more rotary drums to obtain the electromagnetic conversion characteristics. The vapor deposition efficiency is greatly improved.

[0022]

As described above, when a magnetic recording medium is manufactured using the vacuum vapor deposition apparatus of the present invention, it is possible to obtain a magnetic recording medium having excellent electromagnetic conversion characteristics, high vapor deposition efficiency, and high productivity.

This is one evaporation source in the vacuum vapor deposition apparatus, and by providing two or more rotating drums, the magnetic metal is efficiently laminated continuously on the polymer film to significantly reduce noise. In addition, the vapor deposition efficiency can be improved by vapor-depositing a metal vapor stream which has not been conventionally available. In this case, the magnetic metal laminated on the polymer film is
In the layer, an improvement in C / N of +5 dB and an improvement in vapor deposition efficiency of 1.5 times can be seen. Further, when the number of rotating drums is set to 3, that is, when the number of magnetic metal layers is increased from 2 to 3, the C / N is further improved by +1 dB and the vapor deposition efficiency is improved by 1.1 times. However, the effect of increasing the number of rotating drums is significantly reduced from the fourth layer. Regarding the relative position of the rotary drum, when the angle connecting the central axis and the horizontal line is 0 degrees or less, the growth direction of the crystal grains of the magnetic metal is opposite, and when it is 75 degrees or more, the vapor deposition efficiency is not improved so much.

As the polymer substrate used in the examples, polyethylene terephthalate, polyamide, polyimide, polyvinyl chloride, polyethylene naphthalate, polycarbonate, cellulose triacetate and the like can be used.

As the magnetic metal, Co, Ni, Fe and Cr may be used alone or in a mixed form, in the form of a metal or a metal compound. However, in implementing the present invention, Co
The magnetic metal-metal thin film centered on metal was the most excellent in electromagnetic conversion characteristics and magnetic characteristics.

In addition to the above, the present invention is not limited to the production method of the present invention, such as the incident angle at the time of vapor deposition, the vapor deposition temperature, the vapor deposition film thickness, and the introduction of oxygen gas.
The vacuum vapor deposition apparatus of the present invention is not limited to the manufacture of magnetic recording media,
It goes without saying that it can be applied to capacitors, wrapping paper, gold / silver paper, liquid crystal alignment film, and various other functional thin films.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a magnetic recording medium manufacturing apparatus and manufacturing method according to the present invention.

FIG. 2 is a diagram showing a second embodiment of a magnetic recording medium manufacturing apparatus and manufacturing method according to the present invention.

FIG. 3 is a diagram showing a conventional method of manufacturing a magnetic recording medium.

[Explanation of symbols]

 1 polymer film 2 feed shaft 3 rotary drum 4 rotary drum 5 winding shaft 6 intermediate roller 7 crucible 8 magnetic metal 9 oxygen gas nozzle 10 electron gun 11 mask 12 shield plate

Claims (3)

[Claims] 1. An evaporation source has two or more rotating drums, and the rotating drums have a cooling or heating mechanism.
A vacuum vapor deposition apparatus characterized in that an angle between a central axis of two rotating drums and a horizontal line is in a range of 0 to 75 degrees. 2. A method of manufacturing a magnetic recording medium, wherein a ferromagnetic metal thin film layer is continuously laminated on a polymer film by the vapor deposition apparatus of claim 1. 3. The method of manufacturing a magnetic recording medium according to claim 2, wherein the ferromagnetic metal thin film layer is a Co metal compound.