JPS63184925A - Apparatus for producing thin film type magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide the titled medium having magnetic characteristics uniform over the entire part of a magnetic layer by arraying and disposing >=2 units of ion guns as a mechanism for projecting ion current to the transverse position of a drum in a diagonal incident vacuum deposition method. CONSTITUTION:The inside of a vacuum deposition vessel 1 is maintained at about 10<-3>-10<-7>Torr and while a nonmagnetic base material 7 is conveyed along the drum 2, an electron beam is projected from the electron gun 5 to an Fe source 3 to project the Fe vapor diagonally to the material 7 from an Fe source and nitrogen ions are projected from the ion gun 4 to deposit iron nitride by evaporation on the material 7. Three units of the Kaufmann type ion guns 4-1-4-3 having cylindrical ion drawing out ports are juxtaposed in the transverse direction of the cylindrical drum 2. The number of the ion guns to be disposed is determined by the width of the film to be put on the drum and is so determined that the ion current is uniformly projected over the entire width of the film. The uniform formation of the thin film type magnetic layer over the entire width is thereby permitted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for manufacturing a magnetic recording medium, and particularly to a magnetic recording medium using iron nitride (Fex) as a magnetic layer.
N) This relates to an apparatus for forming a magnetic thin film.

The apparatus of the present invention is used to manufacture thin-film magnetic recording media for high-density recording such as magnetic tapes and magnetic prosopy disks.

[Prior art and its problems]

Conventionally, thin-film magnetic recording media, which have a thin magnetic layer made only of ferromagnetic material and do not contain a binder, are being put into practical use for high-density magnetic recording. The most excellent layer is a thin film type magnetic layer formed by diagonally vacuum depositing (oblique incidence vacuum deposition) a ferromagnetic material such as cobalt or cobalt alloy onto a film-like nonmagnetic substrate. Magnetic thin films formed in this way generally have excellent magnetic properties.

However, the cobalt-based thin film magnetic layer does not have sufficient corrosion resistance for practical use, and although this magnetic layer is usually used with a protective film applied, it is still difficult to sufficiently improve the corrosion resistance of this magnetic recording medium. Moreover, the raw material, cobalt, was a scarce resource and expensive.

Therefore, a thin-film magnetic layer using iron may be considered instead of cobalt, but the magnetic properties of iron-based thin-film magnetic layers do not reach the magnetic properties of cobalt-based ones, and the corrosion resistance is also not sufficient. . And in order to solve these problems,
As described in Japanese Patent Application Laid-open No. 60-231924, iron vapor heated and evaporated is incident on a non-magnetic film from an oblique direction, and at the same time, ions of a mixed gas containing nitrogen and oxygen are injected onto the film. A method has been developed to form an iron-based thin film magnetic layer by irradiating a current. Furthermore, for example, JP-A No. 60-236113 and JP-A No. 61-54
Publications such as No. 023 disclose various compositions of such iron-based thin-film magnetic layers, and iron-based thin-film magnetic layers with these compositions have significantly improved corrosion resistance compared to previous ones.
It is also described as having a fairly high coercive force.

As described above, the characteristics of thin-film magnetic layers produced by oblique incidence vacuum evaporation are currently of great importance due to the possibility of higher-density magnetic recording. In order to form a thin film type magnetic layer, an apparatus has been proposed in which a thin film type iron oxynitride magnetic layer is formed on a nonmagnetic film such as polyethylene terephthalate by an oblique incidence vacuum evaporation method. In this device
The above film is stacked on eight cylindrical cooling drums,
Iron is evaporated onto the surface of the cooling drum by oblique incidence vacuum evaporation, and at the same time an ion stream of ionized nitrogen and oxygen gases is supplied to deposit the desired amount on the film. A magnetic layer made of ferromagnetic iron oxynitride is formed.

[Problem that the invention seeks to solve]

However, in the above-mentioned apparatus for forming a thin film type magnetic layer, that is, the apparatus for manufacturing a thin film type magnetic recording medium, although a basic embodiment is explained, for example, the entire magnetic N surface of the magnetic film that is the magnetic recording medium to be manufactured , especially in the width direction of the magnetic film, the composition is not uniform, and even though the central part has certain magnetic properties,
The magnetic properties of the peripheral part are poor, and if you attempt to obtain a magnetic recording medium product by cutting it into a predetermined shape or shape from the original fabric, the magnetic properties of the product will be uneven. Since it is not possible to manufacture recording media, the only way to obtain a high-quality product is to use only the central part when cutting the original material, but because the usable area of the central part is small, the yield of the product is low. There was a problem in that the production efficiency was low and production efficiency could not be improved.

[Means and effects for solving the problem] The present inventor
When we investigated the cause of these defects, we found that in conventional manufacturing of magnetic recording media, one ion gun is normally used as a mechanism for irradiating nitrogen ions, etc., but the ion irradiation by this ion gun is extremely We found out that this is due to the fact that it only works effectively on the central part in the width direction of the magnetic base material, and does not work sufficiently on the peripheral parts, and we will improve this problem and make a full ζ2 crop every Friday. The present invention was developed with the aim of improving retention. In other words, the present invention has been made to solve the problems in the prior art described above, and is a novel method for producing a thin-film magnetic recording medium that has excellent and uniform magnetic properties throughout the formed magnetic layer. The present invention provides an apparatus including: a cylindrical drum; a mechanism for attaching a magnetic material to a film-like non-magnetic base material suspended on the drum and running along its circumferential surface by an oblique incidence vacuum evaporation method; and an apparatus for manufacturing a thin film magnetic recording medium, which is disposed opposite to the drum and is equipped with a mechanism for irradiating the base material with an ion stream, in which an ion gun is used as the ion stream irradiation mechanism in the width direction of the drum. This thin-film magnetic recording medium manufacturing apparatus is characterized in that two or more units are arranged side by side at the positions of.

The present invention will be explained in detail below.

FIG. 1 is a schematic diagram showing an example of a device according to the invention, in which - in a vacuum chamber 1 an i:g cylindrical drum 2, e.g.
An e-source 3 and an ion gun 4 are arranged.

5 is an electron gun that heats the Fe source 3 and causes it to explode, and 6 is a mask that prevents evaporated Fe from adhering to unnecessary areas. While maintaining the vacuum deposition tank 1 at about 10-3 to 10 Torr and transporting the non-magnetic base material 7 along the drum 2, an electron beam is irradiated from the electron gun 5 to the Fe source 3 to deposit Fe.
Fe vapor is obliquely incident on the base material 7 from a source, and nitrogen ions are irradiated from the ion gun 4 to evaporate iron nitride on the base material 7.

FIG. 2 is a schematic diagram showing the configuration of the main parts of the present invention,
Kauffman type ion guns 4-1 to 4-3 having the cylindrical ion extraction port (circular in cross section) in the width direction of the cylindrical drum 2;
Three units are placed side by side.

The cylindrical drum in the manufacturing apparatus of the present invention has a curved side surface, preferably a smooth surface, and serves as a base for forming a curved surface on the film, which is a non-magnetic base material to be hung. be. Therefore, the width of the side surface (curved surface) of the drum must be larger than the width of the film of the magnetic recording medium to be suspended. The rotating type is a roll, and the film placed on its curved surface moves as it rotates, while the fixed type only provides a sliding surface for the film, and other driving sources drive the film. The film is moved and slid over the curved surface, thereby making the film continuously form a curved surface that follows the curved surface of the drum. Another aspect of the cylindrical drum is that the film is cooled so that the incoming magnetic material vapor is deposited on the film by oblique incidence vacuum deposition, which will be described below. Therefore, the cylindrical drum is constantly cooled.
It is cooled by having a cooling medium passed through it or even in contact with an adjacent cooling mechanism).

Examples of the non-magnetic base film used while being suspended on this cylindrical drum include plastic films made of polyethylene terephthalate, polyimide, polyamide, polyvinyl chloride, polynaphthalate, and the like.

A magnetic material is deposited on the curved surface of the film thus formed by the cylindrical drum by oblique incidence vacuum deposition.

As mentioned above, the mechanism is, for example, published in Japanese Patent Application Laid-Open No. 61-540.
Although it is described in detail in Publication No. 23, etc., basically, a magnetic material placed in a crucible or a substance forming a magnetic material is heated by e.g. electron beam irradiation, and the main component atoms are released as vapor. This is then made obliquely incident on a non-magnetic base material and deposited on the base material. Examples of magnetic materials or substances that form magnetic materials include pure Fe and pure CO, as well as Fe atoms.
FeCo containing 0% by weight or more, FeN 1% Fec
There are alloys such as oNi. As mentioned in the section of the prior art, from the viewpoint of the cost of the raw materials, Fe-based materials are preferred.

The apparatus of the present invention is equipped with a mechanism for irradiating an ion stream during this vacuum evaporation, and in particular, this mechanism includes an ion gun placed in a vacuum evaporation tank, which mainly uses N gas, N gas, and N gas.
This method irradiates N+ ions produced by ionizing a gas containing nitrogen atoms, such as H3 gas. As this ion gun, there is a Kauffman type ion gun equipped with a cylindrical or prismatic ion extraction port, which can be used in the apparatus of the present invention. The ion gun is installed so that the emitted ion stream reaches the area on the nonmagnetic film where the magnetic material is deposited by the vacuum deposition mechanism described above. The most distinctive feature of the apparatus of the present invention is that the ion gun is positioned opposite to the drum and in the width direction so that the ion stream produced by the ion gun uniformly irradiates the entire width of the film suspended on the drum. Two or more units are placed side by side at a location.

Therefore, the number of ion guns arranged is determined by the width of the film suspended on the drum, and an appropriate number of ion guns are arranged in parallel so that the ion stream is uniformly irradiated over the entire width of the film.

In the apparatus of the present invention configured in this way, first, a non-magnetic film is suspended on a cylindrical drum, and the film is run at a predetermined speed so that the film forms a curved surface along the outer peripheral curved surface of the drum. A material for forming a magnetic layer is vacuum-deposited with oblique incidence on the film, and at the same time, an ion stream is irradiated from an ion gun to form a magnetic layer on the non-magnetic film.

As explained in detail above, the techniques other than arranging the ion guns in parallel are conventionally known techniques, and each of these operations can be performed by conventional techniques.

The thickness of the magnetic layer of the magnetic recording medium manufactured by the apparatus of the present invention is about 500 to 5000, and the adhesiveness between the film and the magnetic layer on the nonmagnetic film is approximately 500 to 5000.
A desired layer can be provided to mechanically strengthen the magnetic layer or improve magnetic properties. These techniques are also conventionally well known and can be utilized when implementing the apparatus of the present invention.

〔Example〕

Next, the present invention will be explained based on examples and comparative examples.

Embodiment The apparatus of the present invention includes a vacuum evaporation mechanism in a vacuum evaporation tank, a cylindrical drum with a diameter of 400 mm, and a cylindrical drum with a diameter of 30 mm arranged opposite to the curved surface of the drum and in the width direction of the drum.
Two Kaufmann-type ion guns are installed. On this drum? , a 100 mm polyethylene terephthalate film was suspended and run at a speed of 0.5 m/min. This film exhibits a cylindrical curved surface at the part suspended on the drum.

On the other hand, 3N (99.9% purity) Fe as a deposition source is irradiated with an electron beam to heat and evaporate it, and using the above curved surface, evaporation is performed so that the evaporation incident angle is 70 degrees, and at the same time, ion N2 gas was supplied to the gun, and the ion gun was operated at an ion accelerating voltage of 0.6 KV and an ion current of 10 mA to irradiate the ion stream onto the vapor deposited area. The pressure inside the vacuum deposition tank at that time was 5×10 Torr. As a result, a magnetic layer with a thickness of 1,500 layers was formed on the film, and a magnetic film for manufacturing magnetic recording media was obtained.

Comparative Example In the apparatus of the example, the ion gun was replaced with one Kauffman type ion gun with a diameter of 60 mm, the ion current was set to 40 mA to keep the current density the same as in the example, and the other conditions were the same as in the example. As a result, a magnetic layer was formed on the film, and a magnetic film for manufacturing a magnetic recording medium was obtained.

Coercive force Hc and squareness ratio SQ in the film width direction of the magnetic layer of the magnetic film obtained in Examples and Comparative Examples
As a result of measuring by VSM, the results shown in FIGS. 3 and 4 were obtained. In the figure, the solid curve is
The measurement results of the magnetic film according to the example are shown, and the dashed-dotted curve shows the measurement results of the magnetic film according to the comparative example.

As is clear from the results, the magnetic properties of the magnetic film obtained with the apparatus configured according to the present invention were fairly uniform over its entire width.

In the device configured as the comparative example, the magnetic properties of the central portion and the widthwise edges of the obtained magnetic film were significantly different, and when the magnetic film was cut into tapes to produce magnetic recording tapes, The magnetic properties of these products were extremely uneven, making them unsuitable for practical use as magnetic recording media.For this reason, when only the central portion was made into a product, the yield was low and the cost was high. In addition, not only the uniformity in the width direction but also the resulting squareness ratio SQO value was better than that of the comparative example, which allowed for high-density recording.

〔Effect of the invention〕

According to the apparatus of the present invention, a magnetic material or a substance forming a magnetic material is deposited on a non-magnetic substrate by oblique incidence vacuum evaporation method under irradiation with a nitrogen-based ion flow, and a strong material such as iron nitride oxide is deposited on a non-magnetic substrate. Since a thin magnetic layer made of magnetic material can be uniformly generated over the entire width, even if the product is further cut into tape shapes to produce magnetic recording tapes, all of them will have uniform and excellent magnetic properties. , it is possible to manufacture a product with a width close to the full width of the magnetic film, and the yield is high, and the production efficiency is extremely high, which is an excellent and useful effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a device according to the present invention, FIG.
The figure is a schematic diagram showing the main parts of the apparatus according to the present invention, and Figures 3 and 4 show resistance to the position in the width direction of wide films for manufacturing magnetic recording media manufactured according to Examples and Comparative Examples of the present invention, respectively. It is a graph showing the relationship between magnetic force Hc and squareness ratio SQ. The solid curves in FIGS. 3 and 4 show the measured values of the magnetic film according to the example, and the dashed-dotted curves show the measured values of the magnetic film according to the comparative example. In the figure, 1 is a vacuum deposition tank, 2 is a cylindrical drum, and 3 is a
4 is an ion gun, 5 is an electron gun, 6 is a mask, and 7 is a nonmagnetic base material. Figure 1 Figure 2 Figure 3 (Phil Yawata) Figure 4 () is a rum slap I! I)

Claims (2)

[Claims] (1) A cylindrical drum, a mechanism for attaching a magnetic material to a film-like non-magnetic substrate by an oblique incidence vacuum evaporation method suspended on the drum and running along its circumferential surface, and a mechanism disposed opposite to the drum. In an apparatus for manufacturing a thin film magnetic recording medium that is equipped with a mechanism for irradiating the base material with an ion stream, two or more ion guns are arranged side by side at positions in the width direction of the drum as the ion stream irradiation mechanism. 1. An apparatus for manufacturing a thin-film magnetic recording medium, characterized in that: (2) A patent characterized in that the mechanism for attaching the magnetic material is for attaching the magnetic material mainly composed of iron, and the ion gun is for irradiating an ion stream mainly composed of nitrogen ions. An apparatus for manufacturing a thin film magnetic recording medium according to claim 1.