JPH0741938A - Electron beam-heated vaporization source - Google Patents

Abstract

PURPOSE:To provide an electron beam-heated vaporization source capable of mass-producing a magnetic recording medium to be used in a magnetic recording and reproducing device with the error reduced when a digital signal is overwritten. CONSTITUTION:A vapor-deposition material 15 in a refractory vessel 12 is heated by an accelerated electron and vaporized in the vaporization source, and the molten metal is discharged outside the vessel after the vapor deposition is completed. Consequently, a magnetic recording medium capable of realizing a high-density record by overwriting is uniformly mass-produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an object to provide an evaporation source capable of repeatedly performing high-quality vapor deposition while using a refractory container as an electron beam heating evaporation source to increase the speed.

[0002]

2. Description of the Related Art Ni, Cr,
The technology of forming thin films of Cu, Co, etc. uniformly and in a large area has been widely applied starting from the electronic industry, and improving the productivity,
There is an ongoing need to improve thin film quality.

With the progress of the information society, the amount of information to be recorded has remarkably increased, and it is required to increase the recording density of magnetic recording as much as possible, and high-performance magnetic recording that can endure shorter wavelengths and narrower tracks. Development of media is becoming popular. Although many proposals have been made, the one currently put to practical use is a structure in which the surface of columnar fine particles is coated with an oxide of a ferromagnetic metal itself as disclosed in JP-A-53-58206. It has a well-balanced improvement in recording characteristics and durability, and its constituent elements are Co, Ni, and O (JP-A-56-15014), and these magnetic recording layers are formed by oxygen gas. Co, while intervening
Method of electron beam evaporation of Co-Ni (Japanese Patent Publication No. 57-1)
No. 9493) is a typical example, and some proposals have been made for introducing oxygen. However, a position near the base material, which is close to the portion for controlling the incident angle, is often used (Japanese Patent Laid-Open No. 54-1919).
9 and JP-A-58-32234). FIG. 3 is a configuration diagram of a main part of a vapor deposition apparatus used for manufacturing a conventional magnetic recording medium. In FIG. 3, 1 is a polymer film, 2 is a cooling can, 3 is a winding shaft, 4 is a winding shaft, 5 is an evaporation source container, 6 is a vapor deposition material, 7 is an electron beam, 8 is an electron generator, and 9 is A vapor flow, 10 is an oxygen gas introduction nozzle, and 11 is a mask. The evaporation source container is MgO, Al ₂ O ₃ , ZrO
A refractory container such as _{2 and the} like, which is in a horizontally long integrated type (Japanese Patent Publication No. 57-3138) that extends in the direction orthogonal to the moving direction of the substrate, and is discontinuous (arranged at some position in the width direction) Used in. The shape of the container, the conditions of the magnetic material used in the refractory, etc. so that no defects will occur on the substrate during vapor deposition (Japanese Patent Publication No. 61-1).
1224, Japanese Patent Publication No. 61-29126, and Japanese Patent Laid-Open No. 5-128516).

[0004]

However, the above-mentioned conventional structure is not sufficient for obtaining a magnetic recording medium having an excellent error rate in high-density recording in digital recording which has been rapidly progressed in recent years, and particularly a large amount of magnetic field is required. In producing a recording medium with high performance and uniformity and good reproducibility, minute foreign substances mixed in from the evaporation source impede the characteristics, and there is a problem that sufficient uniformity and reproducibility are not satisfied. The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electron beam heating evaporation source that can withstand repeated use and can maintain quality at a high level.

[0005]

In order to achieve this object, an electron beam heating evaporation source of the present invention is an evaporation source for heating and evaporating a vapor deposition material in a refractory container with accelerated electrons. It is designed to be discharged outside the container.

[0006]

With this structure, the refractory container is less likely to be damaged, and the oxide mixed from the inner wall of the refractory container is impacted by the electron beam and is instantly scattered at high speed to damage the deposited film. Therefore, the uniformity and reproducibility equivalent to electron beam evaporation in a water-cooled copper container can be achieved by high-speed evaporation.

[0007]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram of how to use an evaporation source. In FIG. 1, 12 is a so-called refractory container such as magnesia, alumina, calcia, zirconia, 13 is a metal container, 14 is an oxide particle layer provided as a buffer, 15 is an evaporation material, and 16 is made of water-cooled copper. In the solidification container, the groove shape and dimensional relationship of the container are designed so that after solidification, it can be set again in the refractory container as a vapor deposition material. Reference numeral 17 is an accelerating electron beam for heating, and the trajectory of the electrons can be freely selected.

In order to further clarify the effect of the present embodiment, the electron beam heating evaporation source having the above-described structure is incorporated into the apparatus shown in FIG. The result of the characteristic comparison with the one will be described in detail.

The thickness is 7.1 μm, the Young's modulus is 540,590 [Kg / mm ² ] in the longitudinal direction and the width direction, and the average roughness is 3
0Å polyethylene terephthalate film (diameter 15
O ₂ ultrafine particles of SiO ₂ with an average density of 20 particles / μm ² were fixed on the resin was used in advance.) Was wound up along a rotary can cooled to 20 ° C. with a diameter of 1 m to collect oxygen. After introduction, CO (80) -Ni (20) was electron-beam evaporated at an incident angle of 65 ° to 33 ° to form a magnetic layer of 0.18 μm. The oxygen gas introduction nozzle was arranged on the inner surface of the mask that defines the minimum incident angle. The electron beam heating was performed by an electron beam generator with a 90 ° deflection of 40 KV and a maximum output of 300 KW. The refractory container is made of magnesia with a width of 1.1 m, a length of 10 cm, and an internal volume of 5280 cc.
I used the one. The water-cooled copper hearth was designed so that the vapor deposition material solidified in the refractory container could be easily loaded again.

In the conventional example, refractory containers of the same lot were arranged at the same position, and the vapor deposition material was supplied in the form of pellets. The film used for vapor deposition was 5000 m, and it was confirmed by sampling at many points with a three-dimensional scanning electron microscope that the surface uniformity was not so different as to affect the characteristics as a magnetic tape within the same lot.

After vapor deposition, a back coat layer of 0.5 μm was formed.
m, topcoat layer (perfluorostearic acid) 4
nm and slit to 6.35 mm to compare the characteristics. The test deck was used for relative comparison of error rates in overwriting recording with a bit length of 0.24 μm and a track pitch of 10 μm. The length of the magnetic tape is 100m,
Five rolls were selected in the width direction and displayed as an average value of five rolls.

The characteristics of the magnetic recording medium according to this example and the characteristics of the magnetic recording medium of the comparative example are shown in comparison with each other (Table 1).

Immediately after the first vapor deposition was completed, about 30 kg of molten Co (80) -Ni (20) was transferred to a water-cooled copper hearth and solidified to form a polymer film immediately after the completion of the first vapor deposition. The Co-Ni alloy that was set again and solidified was set again in the refractory container, and after evacuation, it was heated and melted again by the heating electron beam and subjected to vapor deposition.

As another embodiment, there is also shown a case where the solidified product is not reused, the refractory container from which the molten metal is discharged is reused, and a new vapor deposition material is set every time vapor deposition is performed.

The conventional example employs a method in which the refractory container is cooled and solidified in a vacuum and then melted and evaporated again in the next vapor deposition.

[0017]

[Table 1]

As is clear from (Table 1), the magnetic recording medium manufactured according to the present example has an excellent effect that high-density digital recording in overwrite recording can be realized in a good state. Is understood to be an excellent manufacturing method. As described above, according to the manufacturing method of this embodiment, in the evaporation source for heating and evaporating the vapor deposition material in the refractory container with accelerated electrons, the molten metal is discharged to the outside of the refractory container after vapor deposition is completed. Thus, it is possible to uniformly manufacture a large number of magnetic recording media capable of realizing high-density digital recording in overwrite recording in a good state.

The cooling method of the container for cooling and solidification, the material and the like can be appropriately selected.

(Second Embodiment) A second embodiment of the present invention will be described below.

FIG. 2 is a state diagram of an evaporation source container according to a second embodiment of the present invention. FIG. 2 (a) shows the refractory container 12 in a horizontal (X- X '), the molten metal 15 made of vapor deposition material is 70 to 85% of the inner volume of the container.
It is controlled to satisfy the condition (the technique for replenishing materials can be selected from general ones). When vapor deposition is completed, the molten metal is solidified in a state of being inclined with respect to the horizontal plane as shown in FIG. 2 (b). It can be said that it is preferable to reduce the remaining amount of the molten metal, but the point is to keep the postures so that they do not become the same in three dimensions.

In order to further clarify the effect of this embodiment, a magnetic recording medium is prototyped by using the apparatus having the above-mentioned constitution, and the result of the characteristic comparison with that obtained by the conventional method will be described in detail. .

A polyimide film with a thickness of 6.1 μm and a Young's modulus of 940 and 1050 [Kg / mm ² ] in the longitudinal and width directions and an average roughness of 30 Å (SiO _{2 with a} diameter of 150 Å) is used.
Of the ultrafine particles of which the average density was 20 / μm ² was fixed on the resin, and the coating layer was previously arranged).
While winding along a rotary can cooled to 0 ° C., oxygen was introduced and Co was electron beam evaporated at an incident angle of 90 to 40 ° to form a magnetic layer of 0.18 μm. The refractory container, electron beam heating, etc. were the same as in Example 1. The inclination angle of the container was the easiest, and one end was raised in the film width direction to incline 10 degrees, and then the other end was raised to incline 10 degrees. Then, the end portion was tilted by 10 degrees and, in that state, it was tilted by 20 degrees with respect to the longitudinal direction of the film and held. The remaining amount of molten metal was set to about 12 kg.

In the conventional example, the amount of molten metal remaining is 1 with horizontal holding.
It was 2 kg. A 60-liter diamond-like hard carbon film was formed on each magnetic layer. The formation is plasma CV in which methane gas is ionized by high frequency discharge to form a carbon film.
Method D was used. Perfluoropolyether as a lubricant was further placed on the carbon film by a 40 Å solution coating method to form a back coat layer of 0.45 μm and processed into a 6.35 mm wide magnetic tape. These tapes were digitally recorded with a 6 .mu. Track and a bit length of 0.2 .mu. By a test deck, and relative error rates were compared by overwrite recording.
The durability was also evaluated by the error rate after adding a 100-pass history at 5 ° C. and 85% RH.

The characteristics of the magnetic recording medium according to this embodiment and the characteristics of the conventional magnetic recording medium are shown in comparison with each other (Table 2).

[0026]

[Table 2]

As is clear from (Table 2), the magnetic recording medium manufactured according to this example has an excellent effect that high-density digital recording under a narrow track condition can be performed with a good error rate. is there.

As described above, according to this embodiment, in the evaporation source for heating and evaporating the vapor deposition material in the refractory container with accelerated electrons, the molten metal is solidified in a posture different from that during vapor deposition of the refractory container,
By reuse as a vapor deposition material, it becomes possible to reproducibly manufacture a thin magnetic recording medium having both excellent durability and good overwrite digital recording performance.

[0029]

As described above, according to the present invention, in the evaporation source for heating and evaporating the vapor deposition material in the refractory container with accelerated electrons, the molten metal is discharged to the outside of the refractory container after vapor deposition is completed. As a result, it is possible to uniformly manufacture a large number of magnetic recording media that can realize high-density digital recording in overwrite recording in a good state.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of usage of an evaporation source in a first embodiment of the present invention.

FIG. 2 is a state diagram of an evaporation source container according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a main part of a manufacturing apparatus used for manufacturing a conventional magnetic recording medium.

[Explanation of symbols]

 12 refractory container 15 vapor deposition material 16 solidification container

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Kunieda 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Koichi Shinohara, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. An electron beam heating evaporation source for an evaporation source for heating and evaporating a vapor deposition material in a refractory container with accelerated electrons, wherein the molten metal is discharged to the outside of the refractory container after completion of vapor deposition. 2. An evaporation source for heating and evaporating a vapor deposition material in a refractory container with accelerated electrons, wherein after the vapor deposition is completed, the molten metal is discharged outside the refractory container and solidified, and the solidified alloy is reused. And electron beam heating evaporation source. 3. An evaporation source for heating and evaporating a vapor deposition material in a refractory container with accelerated electrons, wherein the molten metal is solidified in a posture different from that during vapor deposition of the refractory container and reused as a vapor deposition material. An electron beam heating evaporation source.