JPS58100231A - Method for manufacturing magnetic recording media - Google Patents

Abstract

PURPOSE:To make the coercive force of a magnetic layer constant even when a long-sized substrate is used by setting the vapor ejecting angle to a part which specified the vapor ejecting angle for the formation of the magnetic layer of a mask greater than that to the substrate. CONSTITUTION:A vacuum tank 8 is partitioned by a partitioning plate 9 into an upper room 10 and a lower room 11, which are evacuated independently by exhausting devices 12 and 13. A mask 14 limits the ejecting angle of vapor to a substrate 1 and when the center of a vapor source 5 is P and the tip of the mask 14 is M, the angle theta1 between a normal at the intersection of the prolongation of the segment PM and the substrate 1 on the peripheral side surface of a can 3 and the segment PM is the ejecting angle of vapor. Then, the angle thetaM to a normal at the tip point M of the mask 14 is the incidence angle of vapor to be deposited on the mask 14. When theta1<thetaM, the shape of the mask 14 is not limited specially and may be arc-shaped, and in a polygonal shape of a plane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic recording medium having a ferromagnetic metal thin film as a recording layer.

Until now, the demand for higher density magnetic recording stirrups has been met by increasing the coercive force of magnetic recording media, but as wavelengths become shorter, only the areas near the surface of the media are magnetized. Therefore, the output cannot be increased only by increasing the coercive force, and materials with a high saturation magnetic flux density are being used. One is an extension of the conventional coating type, and 2. Fine particles of ferromagnetic metals such as iron or alloys, which are diluted with a non-magnetic material such as a binder but have essentially a high saturation magnetic flux density, are coated with iron oxide. One of the magnetic recording media used in place of the above is a medium that does not use a binder and has a ferromagnetic metal thin film as its magnetic recording layer.Since vacuum deposition is used to form the thin film, it is commonly called a vapor-deposited tape. Some parts have been put into practical use.

This vapor-deposited tape has a short history, and there are many issues that need to be improved on an industrial scale.

One of them is the control of coercive force. In particular, the development of technology to stably control large coercive forces is an important theme.

A vapor deposition method that has the possibility of stably controlling the coercive force is the so-called oblique vapor deposition method disclosed in Japanese Patent Publication No. 41-19389.

However, the problem with carrying out this method is that the vapor deposition efficiency is low, and that the coercive force changes as the incident angle changes, and this phenomenon becomes more pronounced as the coercive force increases.

3. The present invention provides a method that can suppress changes in coercive force caused by changes in incident angle to a practical level,
The details will be explained below using the drawings.

FIG. 1 shows a cross-section of essential parts of a vapor deposition apparatus for carrying out the method of the present invention. Although an example of a two-unit configuration is shown here, any device that satisfies the requirements described below can be used without being particular about this when implementing the method of the present invention.

A polymer molded substrate (hereinafter simply referred to as a substrate) 1 is configured to move from a feed shaft 2 along a rotary can 3 and be wound up on a winding shaft 4.

In this figure, other elements of the winding system, such as a flow roller and an expander roller, are omitted, but it goes without saying that they may be included as necessary.

The rotary can 3 also serves as a cooling support, and instead of this, an endless belt made of, for example, 5US304 stealth #1 thin plate may be used. Heat theory: This belt should also be cooled before use.

Furthermore, a plurality of cans can be used to perform one repetition of vapor deposition.

As the evaporation source 6 disposed opposite the rotating can 3, any known evaporation source can be used, but according to experiments conducted by the inventors, electron beam heating is the most suitable. In the diagram,
The evaporation source 5 is schematically shown as a container 6 and a evaporation source 7,
Illustration of the electron source is omitted.

The interior of the vacuum chamber 8 is divided into two chambers 1o and a lower chamber 11 by a partition plate 9.
It is divided into two parts. The royal chamber 10 and the lower chamber 11 are usually evacuated by separate exhaust devices 12,13, respectively. mask 1
Reference numeral 4 serves to limit the angle of incidence of vapor onto the substrate 1, and when the center of the evaporation source 6 is P and the tip of the mask 14 is M.

The angle θ1 formed by the PM and a normal line drawn at the point where the extension of the PM intersects with the substrate 1 on the circumferential side of the can 3 represents the incident angle of vapor.

Further, the angle θM formed with the normal line made at point M at the tip of the mask 14 is the incident angle of the vapor deposited onto the mask 14. It is a requirement of the present invention that θl and θM have the relationship θ1<19M, and as long as this is satisfied, there is no particular restriction on the shape of the mask 14, and it may be a part of an arc or a straight line. It may be a combination.

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

[Example 1] ↓ Polyethylene 1 with a width of 500 mm and a thickness of 10.6 μm as a substrate
- Using a lente terephthalate film, the incident angle θ1 = 700. θM-80° (see Figure 1)
Then, an alloy layer of 80% C1Q-120% N was formed on the substrate to a thickness of 0.1 μm. The degree of vacuum in the lower chamber is 2
It was X10 Torr. The obtained magnetic layer had a coercive force of 1'i:1050 Oersteds, and a squareness ratio of the BH curve was 0.96.

Then, for comparison, a magnetic layer was formed under the same conditions as in this example except that it was set at 0M-30°.

FIG. 2 shows sampling in the longitudinal direction of the sample fabricated in this example and the sample fabricated in the comparative example.
The coercive force distribution in the width direction is shown in the form of error bars.

As is clear from this, by the method of the present invention, 6.,-
' For example, the coercive force is constant, and its variation in the width direction is also very small. However, according to the comparative example, as the 1 coercive force increases, the variation in the width direction also increases.

Similar comparisons were made for the following examples, but 11,000
It is shown by comparing the coercive force at the time of m deposition and immediately after the start.

[Example 2] On a polyethylene terephthalate film with a length of 2050 m, a width of 500 mm, and a thickness of 15 μm, the incident angle θ1 of vapor was
A magnetic layer consisting of 00100% at -73° was formed to a thickness of 0.2 μm. The angle of the tip of the mask is θM = 80
', and the degree of vacuum in the royal family is 1,7 x 'K)"rorr
Met. The obtained coercive force was initially 1000 m.

At the time of 20 oom, each was 1200 oersted, the squareness ratio of the B-H curve was o, 97, and the uniformity in the width direction did not change.

On the other hand, for comparison, when formed with 0M-200, 1
At the time of 0 oam, the coercive force varied from 1220 to 141 oersted. At this time, C deposited on the tip of the mask
The thickness of O was 19 mm, and the angle of incidence was substantially changed.

[Example 3] Go85 was applied to a polyethylene terephthalate film with a width of 6 oomm and a thickness of 11.6 μm at an incident angle θ1 = 600.
A magnetic layer consisting of %-0r16% was formed. Vacuum degree 1
×10 TOrr, θ, = 85゜0M-76゜
A comparative analysis was conducted for the following cases. The initial value at 1000m is coercive force 980 oersted, squareness ratio of B-H curve 0.
98, and the coercive force in the width direction: /Ij was uniform in all cases.

A more detailed examination of these two sides revealed that 200
As the length increases from 0 m to 3000 m, the coercive force tends to change slightly in the case of θ = 86° and in the case of 01-76°. From this point of view, it is preferable not only to maintain the relationship θl<θ proof, but also to make θV as large as possible. However, if the evaporation position shifts due to a drop in the evaporation level, the angle of incidence tends to change, so it is practical to set it to 1 θ1-75 to 860.

However, this is not the case if a feeder is provided to replenish the evaporation material to the evaporation source to accommodate the lengthening of the substrate, thereby keeping the level of the molten metal at the evaporation source constant.

[Example 4] 0080%-N was deposited on a polyamide substrate with a thickness of 8.5 μm.
A magnetic layer made of 20% i was formed to a thickness of 0.16 μm. Oxygen was introduced into the royal room, and the vacuum level was 4.6 x 10.
Vapor deposition was performed while maintaining a vacuum level of Torr.

Note that θ1=46° and θM=80°.

The coercive force of the obtained magnetic layer was 920, and the squareness of the B-H curve was 0.88. The values were substantially uniform in both the 11 vi'l force direction and the longitudinal nof direction over the 4000 m length of the substrate. Because IJZ is soft, when θM = 200, the coercive force increases by about 15% at 1000771,
At 2000m, it's a 34% increase #lll. Then, 3QOO
In order to control the A-deposited film thickness, the film movement speed was set to 4.
It was necessary to increase the power of the input electric beam by 30%. It can be seen from this that the present invention is able to maintain the set conditions and is excellent in controlling the film 1v.

In addition to the first device used in these Examples, a high frequency electrode was provided between the film as a substrate and the evaporation source, and 1
It was confirmed that the effects of the present invention can be obtained even when ion brating is performed at a high frequency of 3.56 Ml (z).

And as evaporation Kiri, F6゜Go −V,
Go-W, Go-Mn, Go-Ti, C1o-8i
.

It was confirmed that the effects of the present invention can be obtained even when Go-N1-Or, Go-Pt, etc. are used.

As described above, the method of the present invention sets the vapor incident angle to the part of the mask that regulates the vapor incident angle for magnetic layer formation to be larger than the vapor incident angle to the substrate. To provide a vapor-deposited tape for magnetic recording and reproducing, which can keep the coercive force of a magnetic layer and the squareness ratio of a B-H curve constant even when a magnetic material is continuously vapor-deposited on a substrate, and thus has stable quality. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of an apparatus for carrying out the method of the present invention, and Fig. 2 is a cross-sectional view showing an example of a device for carrying out the method of the present invention. FIG. 1... Polymer molded substrate, 3... Rotating can, 6...
...Evaporation source, 9...Partition plate, 8...
Good air tank, 10...upper chamber, 11...lower chamber,
12.13...Exhaust system, 14...Mask.

Claims (1)

[Claims] When a ferromagnetic material is continuously deposited on a polymer molded substrate moving along a cooling support, the angle of incidence of the vapor near the part of the mask that limits the angle of vapor incidence for magnetic layer formation. A method for manufacturing a magnetic recording medium, characterized in that the angle of incidence is larger than the angle of incidence for forming the magnetic layer.