JPS6116031A - Production of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a satisfactory vertical magnetic recording medium which is free from wrinkles by setting an insulator to at least a part between a forming part of a vapor deposition film and a start part of contact between a substrate and a cylindrical can in order to separate the substrate from the can and setting different levels of potential between the can and a conductor film on the substrate for vapor deposition of a Co-Cr vertically magnetized film. CONSTITUTION:A cylindrical can 2 is grounded, and a roller 4 set at the outgoing side of a substrate 8 is connected to a power supply 11 in order to secure a difference of potential between a conductor part on the surface of the substrate 8 and the can 2. An insulator 14 is put in between a contact start part 12 (an arrow head) to the can 2 of the substrate 8 and a forming part 13 of a vapor deposition film in order to separate the substrate 8 from the can 2. An end of the insulator 14 is fixed to a tool 15. The attraction between the can 2 and the substrate 8 is small at an area where the insulator 14 exists. While the electrostatic attraction is produced by the voltage applied to a conductor film at an area where no insulator 14 exists. Thus the substrate 8 touches close to the can 2 and therefore no wrinkle is produced. Under such conditions, a Co-Cr vertically magnetized film is vapor-deposited. Thus a vertical magnetic recorder produces no wrinkle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a perpendicular magnetic recording medium with excellent high-density recording characteristics.

(Structure of conventional example and its problems) A perpendicular recording method is known as a method with excellent short wavelength recording characteristics. This utilizes residual magnetization in the direction perpendicular to the film surface of the medium. Therefore, this method requires a perpendicularly magnetized film in which residual magnetization remains in a direction substantially perpendicular to the film surface.

As a perpendicular magnetization film, a so-called Co--Cr perpendicular magnetization film containing Co and Crf as main components has excellent characteristics. Co-Cr perpendicularly magnetized films are manufactured by the spinning, taling, and vacuum deposition methods (including methods such as ion silating, in which a part of the evaporated atoms is ionized to deposit the film), but the latter method is particularly effective. The method allows very high film deposition rates to be achieved and is suitable for mass production. However, as will be explained below, when a Co--Cr perpendicular magnetization film was actually fabricated by vacuum evaporation, a problem occurred in that various wrinkles were generated. If wrinkles occur, it is impossible to use the material as a magnetic recording medium, and some kind of solution is required.

As a method for producing a Co--Cr perpendicularly magnetized film by a vacuum evaporation method, the most excellent method is to carry out the evaporation while moving the substrate around the circumferential surface of a cylindrical can.

FIG. 1 is a front view of the interior of a conventional vacuum evaporation apparatus for producing a Co--Cr perpendicularly magnetized film.

A substrate made of a polymeric material runs along the circumferential surface of the cylindrical can 2. Reference numerals 3 and 4 are a board entry roller and a board exit roller, respectively, which guide and run the tape-shaped board 1ff. 5 is an evaporation source, and 6 is a shielding plate.

The operation of the conventional vacuum evaporation apparatus configured as described above will be explained below.

The substrate 1 made of polymeric material guided by the substrate entry roller 3 runs under the circumferential surface of the cylindrical can 2 as it rotates, and is guided to the winding side by the substrate exit roller 4. Note that the temperature of the cylindrical can 2 can be arbitrarily set to a temperature of around 350° C. on the circumferential surface. Evaporation source 5 is Co
-Cr alloy ingo.

Heat and evaporate completely. Due to the shielding plate 6, only the evaporated atoms having a component close to normal incidence are exposed to the group made of polymer material.
1 to form a Co--Cr perpendicular magnetization film.

However, when a Co--Cr perpendicular magnetization film is manufactured with the above configuration, the following problems occur. That is, Co −
When a signal is recorded and reproduced in a Cr perpendicularly magnetized film, a film having a large coercive force He perpendicular to the film surface can obtain a high reproduction output. The temperature on He increases as the substrate temperature Tsub during evaporation increases. In order to put a Co-Cr perpendicular magnetization film into practical use, at least 3000e of He is required.
For this purpose, the substrate temperature T during evaporation must be 1.20°C.
As a result of the experiment, it became clear that the above steps had to be taken. More preferably, a film having a value of 5000e or more is required on He, but in this case, the substrate temperature Tsub during vapor deposition must be 200° C. or more. Note that the substrate temperature Tsub during vapor deposition mentioned here refers to the temperature of the peripheral surface of the cylindrical can. Further, as the substrate 1 made of a polymeric material, a polyethylene terephthalate film, a polyimide film, or a polyamide film is suitable from the viewpoint of surface properties, stability, mass productivity, etc. However, by using these films and using the method shown in FIG.
If vapor deposition is performed at a temperature of 20° C. or higher, wavy wrinkles will occur in the vapor deposited area.

FIG. 2 is a three-dimensional diagram showing how wavy wrinkles are generated on the substrate 1 at this time, and numeral 7 indicates the wavy wrinkles. It has been revealed that such wavy wrinkles 7 occur in the vapor deposition part when the contact between the cylindrical can 2 and the substrate 1 is insufficient.

Therefore, one possible way to prevent this is to form a conductive film on the substrate 1 made of a polymeric material, create a potential difference between this conductive film and the cylindrical can 2, and bring them into close contact by electrostatic attraction. . Note that when permalloy or Ti is used as this conductive film, the recording/reproducing characteristics and orientation of the perpendicular magnetic recording medium are improved.

FIG. 3 is a three-dimensional view showing a state in which a Co--Cr perpendicular magnetization film is deposited by providing a potential difference between the conductor film and the cylindrical carrier 2 as described above. 8 is the surface (cylindrical can 2
This is a substrate made of a polymeric material with a conductor film formed on the surface (not in contact with the surface). The voltage applied between the conductor film and the cylindrical can 2 may be either a direct current voltage or an alternating current voltage. According to the above method 1, the wavy wrinkles 7 as shown in FIG. 2 disappear, but random wrinkles 9 are generated when the substrate 8 comes into contact with the cylindrical can 2. The possible causes of this occurrence are as follows.

When the substrate 8 contacts the cylindrical can 2, the cylindrical can 2
Since the temperature is high, the substrate 8 is rapidly heated and deformed.

Random wrinkles 9 are generated on the substrate 8 because the substrate 8 is brought into close contact with the cylindrical can 2 due to electrostatic attraction in a state where the deformation is not corrected.

FIG. 4 is a three-dimensional view of a device that attempts to improve the random wrinkles 9 in FIG. 3. The configuration of this device is almost the same as in Fig. 3, but in Fig. 4, the board entrance roller 3 is
The difference is that the f roller is changed to 3'. 2. The surface of the roller 3' is generally made of rubber. When the substrate 8 made of a polymer material with a conductive film formed on its surface starts to come into contact with the cylindrical can 2, it is pressed against the cylindrical can 2 by two blowers 3'. However, even with this configuration, when the temperature of the cylindrical can 2 is increased and a voltage is applied between the substrate 8 and the cylindrical can 2 to produce a Co-Cr perpendicular magnetization film, the substrate 8 is attached to the cylindrical can 2. Upon contact, deformation occurs due to rapid heating, and before this deformation is corrected, creases 10 are generated due to being pressed down by the second roller 3'.

As described above, the conventional structure has the problem that wrinkles occur in the substrate made of the fourth polymer material when the Co-Cr perpendicularly magnetized film is deposited, making it unusable as a magnetic recording medium. Ta.

(Objective of the Invention) The present invention solves the above-mentioned problems, and aims to provide a method for manufacturing a good perpendicular magnetic recording medium without wrinkles.

(Structure of the Invention) The present invention is based on a substrate made of a polymeric material having a conductive film formed on its surface, which is running on the circumferential surface of a cylindrical can whose temperature has been raised to 120° C. or higher.

When forming a perpendicularly magnetized film mainly composed of This is a method for manufacturing a perpendicular magnetic recording medium in which an insulator is arranged to separate the conductive film and the cylindrical can, and the conductor film and the cylindrical can are made to have different potentials. A recording medium is obtained.

(Description of Examples) FIG. 5 is a front view of the inside of a vacuum evaporation apparatus for explaining an example of the manufacturing method of the present invention.

In this embodiment, the cylindrical can 2 is grounded and the substrate exit roller 4 connects the cylindrical can 2 with the conductive portion on the surface of the substrate 8 made of a polymeric material on which a conductive film is formed. It is connected to a power source 11 to provide a potential difference therebetween.

Note that the potential of the substrate output roller 4 may be positive or negative,
It can also be an exchange.

The arrow 12 in the figure indicates the location where the substrate 8 begins to come into contact with the cylindrical can 2, that is, the contact start portion. 1:l; is a deposited film forming part, where a Co--Cr perpendicular magnetization film is formed. 1
4 is an insulator provided between the contact initiation part 12 and the deposited film forming part 3 to separate the substrate 8 and the cylindrical cap 72, and a jig for fixing one end of the 15-piece insulator 14. It is. Since the insulator 14 is fixed by the fixing jig 15, it slides on the surfaces of the substrate 8, the cylindrical can 2'id, and the insulator 14. Therefore, it is desirable for the insulator 14 to have a friction coefficient T1 as small as possible.

Our experiments have shown that Teflon-based notebooks are the most suitable.

With the above arrangement, in the area where the insulator 14 exists between the substrate 8 and the cylindrical can 2, by appropriately setting the film thickness of the insulator 14, the cylindrical can 2 and Even if a potential difference exists between the substrate 8 and the conductive film, the attractive force acting between the two is weak. On the other hand, in the part where the insulator 14 is not present, a voltage is applied to the conductive film on the substrate 8 by the power source J, so a strong electrostatic attraction is created between the cylindrical can 2 and the conductive film on the substrate 8. The board 8 is a cylindrical can 2.
stick to.

In the conventional method shown in Figure 3 and Figure 1 (
When the substrate 8 comes into contact with the cylindrical can 2, the substrate 8 is rapidly heated and deformed, and before this deformation is corrected, it was in close contact with the cylindrical can.This causes random wrinkles. Alternatively, in the present invention, after the substrate 8 comes into contact with the cylindrical can 2 via the insulator 14,
Between the trench where the insulators 1 and 1 disappear, the force between the board 8 and the cylindrical can 2 other than the tension force of the board 8 is weak, so the board 8 almost passes over the insulator 14. I can move freely. That is, when the substrate 8 begins to come into contact with the cylindrical can 2 through the insulator 14 at the portion indicated by the arrow 12, the substrate 8 is rapidly thermally deformed, but during this deformation, the gap between the substrate 8 and the cylindrical can 2 is Since there is almost no strong force such as electrostatic attraction acting on the material, the thermal deformation is completely completed without generating random wrinkles or creases. Then, in the part where the insulator 14 is removed, the substrate 8 is thermally deformed and the cylindrical can 2 is moved by electrostatic attraction.
Since it sticks to the cylindrical case, no wrinkles occur when it sticks to the cylindrical case. In the vapor deposited film forming section 13, since the substrate 8 is stuck to the cylindrical can 2 due to the electrostatic attraction between the conductor film on the substrate 8 and the cylindrical can 2, the second
There are no wavy wrinkles as shown in the figure. in this way,
According to the method of the present invention, no wrinkles occur at all.

Incidentally, the circumferential surface of the cylindrical can 2 is generally coated with hard Cr film, but instead of such a metal film, At203
There is no problem even if it is coated with an insulating material such as. In addition, the specific voltage value of the power source 11, the film thickness of the insulator 14, the length of the insulator 14 between the contact starting part 12, etc., the diameter and temperature of the cylindrical can 2, the width and film thickness of the substrate, etc. It varies depending on the situation. - As an example 2, the diameter of the cylindrical can (i75
0crn, temperature 250℃, substrate width and film thickness 15crn and 50μm, respectively.The conductor film on one substrate was 30cm thick.
00 permalloy, the voltage of the power supply 11 is 1
00 to 250V, the insulator 14 is a Teflon notebook with a film thickness of 50 μm, the length of the insulator 14 from the contact start part 12 is f, 1
When it is 10 to 30 crn, it is a long Co with no wrinkles.
A -Cr perpendicular magnetic recording medium was stably obtained. Further, even if one end of the insulator I4 has a thickness that is uniform with the other parts as shown in FIG. 6(a), the desired purpose can be achieved; however, as shown in FIG.
) It was confirmed that the stability could be further improved by using a multi-stage structure as shown in FIG. 6(c) or by using an inclined structure as shown in FIG. 6(c).

Next, specific examples of the present invention will be described.

Using the vacuum evaporation apparatus shown in Fig. 5, a 2500X thick Gu-Malloy film was deposited on a polyamide film 15cm wide and 10μm thick, and then a 1500X thick film was deposited on top of it.
A Co--Cr perpendicular magnetization film of X was deposited. However, width 15
A deposited film was not formed at both ends 10 in the width direction of the film having a width of 10 cm as a mernon part.

That is, the width of the deposited film is 13 crn.

- When depositing the e-malloy film, the temperature of the circumferential surface of the cylindrical can 2 with a diameter of 50 crn was set at room temperature, so no wrinkles were formed. When further depositing a Co-Cr perpendicularly magnetized film on the permalloy film, the temperature of the circumferential surface of the cylindrical can 2 is set to 260°C, and the metal roller 4 is heated to 70°C by the power source 11.
A voltage of V was applied. As the insulator 14, Teflon/-Teflon with a film thickness of 30 μm was used.

The length of the contact start part 12 and the insulator 14 is 20 cr.
It was set as n. In the perpendicular magnetic recording medium after vapor deposition,
There were no wrinkles. In addition, He of the Co-Cr perpendicular magnetization film
The soil was 7000e, and showed excellent short wavelength recording and reproducing characteristics.

(Effects of the Invention) As explained above, according to the method of the present invention, it is possible to completely remove wrinkles that conventionally occur when depositing a Co--Cr perpendicularly magnetized film on a substrate made of a polymer material. This makes it possible to provide a wrinkle-free perpendicular magnetic recording medium.

[Brief explanation of drawings]

Figure 1 is a front view of the inside of a conventional vacuum evaporation apparatus for producing a Co--Cr perpendicularly magnetized film, and Figures 2 to 4 are three-dimensional diagrams illustrating the wrinkles that occur on a substrate in a conventional vacuum evaporation apparatus. 5 is a front view of the inside of a vacuum evaporation apparatus for explaining an embodiment of the manufacturing method of the present invention, and FIG. 6 is a diagram for explaining the shape of one end of an insulator. 1.8. Substrate, 2. Cylindrical can, 3. Substrate entry roller, 4. Substrate exit roller, 5. Evaporation source, 6 Shielding plate,
7... Wavy wrinkles, 9- Random wrinkles, 10... Folded wrinkles,
11. Power supply, 12. Arrow, contact start part, 14. Insulator, 15. Insulator fixing jig. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] A perpendicularly magnetized film mainly composed of Co and Cr is placed on a substrate made of a polymeric material with a conductive film formed on its surface, which is running along the circumference of a cylindrical can whose temperature has been raised to over 120°C. is formed by a vacuum evaporation method, an insulator for separating the substrate and the cylindrical can is disposed at least in a portion between the contact initiation portion of the substrate to the cylindrical can and the vapor deposited film forming portion. , and a method for manufacturing a perpendicular magnetic recording medium, characterized in that the conductor film and the cylindrical can are set to different potentials.