JPH01146120A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To feed a nonmagnetic base film without impairing the flatness thereof by specifying undulations to a specific height or below. CONSTITUTION:Directions of the waves 60, 61 of the base film 34 are intersected by adjusting guide rollers 40a-40d and thereafter, the prescribed film forming stage is executed. Namely, the direction of the waves 60 of the film 34 extended between the guide rollers 40a and 40b is intersected with the direction of the waves 61 of the film 34 extended between the guide rollers 40c and 40d, by which the waves are decreased. The waves 60 extending downward to the right are formed between the rollers 40a and 40b and the waves 61 extending downward to the left are formed between the rollers 40c and 40d by adjusting the inclination and height of the rollers. The waves of the film 34 are thereby suppressed and the height of the waves is decreased to about <=1mm. The magnetic recording medium having the excellent flatness is thus produced.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a magnetic recording medium and a method for manufacturing the same, and more specifically, a method for manufacturing a magnetic recording medium using a vapor phase deposition method and a method for manufacturing the same. Related to magnetic recording media.

(Prior art) In the production of magnetic recording media using a vapor phase film deposition method such as a sputtering method, a rotating cooling drum is usually placed at a position facing a material supply source such as a sputtering source, and a rotary cooling drum such as PET or the like is placed on its surface. A nonmagnetic base film is placed along the drum, and the film is fed as the drum rotates.

However, the disadvantage of this method is that it is difficult to control the substrate temperature because the drum has a large heat capacity, and if the temperature is set to a low temperature, sufficient characteristics of the magnetic R film such as Go-Or cannot be obtained, and the characteristics If the drum temperature is set to, for example, 200° C., which is necessary for this purpose, the heat will cause plastic films such as PET films to soften or melt.

Regarding this problem, the present applicant previously proposed
In No. 223, we proposed a water-cooled flat plate method, and were able to provide a method for manufacturing a magnetic recording medium that does not cause problems such as thermal deformation of the nonmagnetic base film. FIG. 1 shows an example of a water-cooled flat plate system. In FIG. The guide rollers are also used to control the waviness that occurs during the movement of the base body 20. 30 is a cooling plate, which is installed at a constant distance d from the base body 20 to which tension is applied. Reference numeral 32 denotes a target, which is provided with Co--Cr or the like for forming a magnetic recording film. When such a target 32 is hit by ions of an inert gas such as argon formed by sputtering discharge, 00% Cr atoms (sputtered particles) are ejected. These particles adhere to the substrate 20 one after another to form an alloy film with a high coercive force. The cooling plate 30 cools the entire corresponding area of the base 20, and the temperature of the base can be controlled by adjusting the distance d between the base and the cooling plate, thereby avoiding problems caused by the large heat capacity of the drum system. be able to. In addition, in the water-cooled flat plate method, in order to manufacture double-sided recording media such as floppy disks, another set of cooling plates and a target are used to form a similar magnetic film from the back side of the non-magnetic base film. Modifications such as adding a similar configuration to provide a soft magnetic film under these magnetic recording films are possible.

(Problems with the conventional technology) In the water-cooled flat plate method, the non-magnetic base film is supported by guide rollers, so the flatness of the film stretched at the film forming position between the rollers is slightly reduced. A problem arose in that floppy disks were undulated. This point will be explained with reference to FIG. 2, which shows the apparatus of FIG. 1 viewed from the direction of the target 32. Waviness 33 is produced in the film. This wavy film is often fixed because it is exposed to the high temperature of the target, and the product has undulations of 2 mm or more in height as shown in Figure 3 (here, undulations are defined as the magnetic recording medium being placed on a horizontal surface). A similar problem occurs when magnetic recording films are formed on the front and back sides of a base film (defined as the total height of the magnetic recording medium minus the total thickness when placed on the base film). This caused uneven contact between the head and the jacket and the liner when the floppy disk rotated, which in turn affected the magnetic recording and reproducing characteristics.

(Object of the Invention) Therefore, the object of the present invention is to provide a highly planar magnetic recording medium and a method for manufacturing a magnetic recording medium in which vapor phase film formation of the magnetic recording medium is performed by a water-cooled flat plate method. It is an object of the present invention to provide a method for manufacturing a magnetic recording medium that allows the magnetic recording medium to be provided without impairing its flatness.

(Summary of the Invention) The present invention feeds a non-magnetic base film along a plurality of cooling plates with a plurality of guide rollers while maintaining a predetermined interval with respect to the cooling plates. A method for manufacturing a magnetic recording medium, in which a magnetic recording film is formed on the surface of the film by a vapor deposition method such as a sputtering method, wherein the directions of waviness of the non-magnetic base film at the plurality of film-forming locations cross each other. The present invention provides a method for manufacturing a magnetic recording medium, characterized in that the guide rolls are adjusted so that the waviness cancels out each other, and a magnetic recording medium with less waviness and high flatness obtained in this way.

According to the method of the present invention, there is no need to be particularly concerned about the natural occurrence of waviness in the base film, and the waviness at the second film-forming location is increased so as to cancel out the height of the waviness that occurs at the first film-forming location. 1 by adjusting the guide rollers, and in this way, substantial elimination of waviness can be easily achieved. Although it is very difficult to eliminate waviness, it is extremely easy to correct the direction of waviness, which made it possible to establish the method of the present invention.

(Detailed Description of the Invention) Next, the present invention will be described in detail in conjunction with preferred embodiments.As is clear from the gist of the invention, the present invention is effective when film formation is performed at least twice, The method described in FIG. 1 is not effective. Fortunately, however, in manufacturing methods for magnetic recording media using vapor phase deposition methods such as sputtering, two or more layers are often deposited, and floppy disks in particular always have magnetic recording layers on both sides. Furthermore, when a metal magnetic film is used, a soft magnetic film is first formed on a non-magnetic base film, and then a magnetic recording film is formed on top of that, so that the present invention can be applied. The scope is extremely wide.

FIG. 4 shows one example of a method of forming a film by sputtering on a magnetic recording medium to which the present invention can be applied, and FIG. 5 shows still another example.

In FIG. 4, 34 is a non-magnetic base film such as PET, 36 is a supply roll, 38 is a take-up roll, 40a,
40b, 40c, 40d are guide rollers, 42a, 42
b is a target, 44a and 44b are water-cooled cooling plates,
d is a gap formed between the cooling plate and the base film 34. Targets 42a and 42b are both Co-C
r alloy, and this alloy is deposited on the surface of the base film 34 using argon as a sputtering gas. In this way, magnetic recording films are formed on both sides.

In FIG. 5, 46 is a non-magnetic base film such as PET, 48 is a supply roll, 50 is a take-up roll, and 52 a
, 52b, 52c, and 52d are guide rollers, 54a and 54b are targets made of a soft magnetic material such as Fe-Ni alloy (permalloy, supermalloy), and 56a and 56b are targets made of a hard magnetic material such as Co-Cr. , 58a and 58b are water-cooled cooling plates, and d is a gap formed between the cooling plate and the base film 34. Both targets 42a and 42b are Co-
This alloy is a Cr alloy, and this alloy is deposited on the surface of the base film 34 using argon as a sputtering gas. In this way, a magnetic recording medium having a horizontal magnetic recording film and a perpendicular magnetic recording film on both sides is manufactured.

The method of the present invention is characterized in that in such a manufacturing apparatus, a predetermined film forming step is performed after the directions of the undulations of the base film are made to intersect by adjusting the guide rollers. That is, in the embodiment shown in FIG.
By crossing the directions of the base film stretched between guide rollers 52a and 40d, or in the embodiment shown in FIG. By crossing the directions of the base films stretched between 52c and 52d, waviness can be reduced overall.

To explain this point more specifically, FIG. 6 is a diagram of the device in FIG. 4 viewed from the direction of the target (the example in FIG. 5 is also essentially the same, so the explanation is omitted), and the guide roller Wave-like undulations are generated between them due to subtle differences in their angles, and the direction of these undulations is determined by the mutual relationship of the rollers.

Therefore, according to the present invention, the roller 40a is adjusted by adjusting the inclination (inclination in the in-plane direction in the figure) and height (inclination in the direction perpendicular to the plane in the figure) of the roller.

A undulation 60 extending downward to the right is formed between the rollers 40b, and a undulation 61 extending downward to the left is formed between the rollers 40c and 40a. This suppresses waviness of the base film.

An example is the guide roller 40a.

40b spacing, 40c, 40d spacing 300 each
Co--Cr was deposited on both sides of a PET substrate film with a width of 250 mm and a thickness of 40 am using argon gas as a sputtering gas according to the method described in connection with FIG.
An alloy film was formed. When the optimum undulation height was determined by adjusting the crossing angle of the undulations, it was possible to reduce the undulation height to about 1 mm or less.

For comparison, when the direction of the waviness was made to match the feeding direction of the base film, the height of the waviness was 2 mm or more. When the direction of the waviness was made oblique to the feed direction and almost coincident with it, the waviness also became 2 mm or more. Furthermore, although careful adjustment was made to eliminate the undulations, the undulations could not be eliminated7.

(Function and Effect) As described above, according to the present invention, by adjusting the guide rollers so that the directions of the undulations cross each other at a plurality of film-forming locations, the undulations, which have been difficult to overcome in the past, can be solved by magnetic fields with excellent flatness. Recording media can be manufactured.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of a vapor phase film forming apparatus, Fig. 2 is an explanatory diagram showing the occurrence of waviness in a conventional film forming method, and Fig. 3
The figure shows the height of waviness of a magnetic recording medium obtained by a conventional film-forming method, Figure 4 is a schematic diagram of a film-forming apparatus to which an embodiment of the present invention is applied, and Figure 5 shows a diagram to which an embodiment of the present invention is applied. FIG. 6 is a schematic diagram of another film forming apparatus for use in the present invention, and FIG. 6 is a plan view of a main part of the apparatus shown in FIG. 4 for explaining the present invention in detail. 34: Non-magnetic base film such as PET, 36: Supply roll, 38 Two take-up rolls, 40a. 40b, 40c, 40d Ni guide roller, 42a, 4
2b: target, 44a, 44b: water-cooled cooling plate, d: gap formed between the cooling plate and the base film 34, 46: non-magnetic base film such as PET, 48:
Supply roll, 50: Take-up roll, 52a, 52b, 52
c, 52d Ni guide rollers, 54a, 54b: Target made of soft magnetic material such as Fe-Ni alloy (permalloy, supermalloy), 56a, 56b: Target made of hard magnetic material such as Co-Cr, 58
a, 58b: Water-cooled cooling plate.

Claims (2)

[Claims] (1) A magnetic recording medium in which a magnetic recording film is formed on at least one surface of a non-magnetic base film by a vapor deposition method such as a sputtering method, characterized in that the waviness height is 1.0 mm or less. magnetic recording media. (2) A non-magnetic base film is fed by a plurality of guide rollers along a plurality of cooling plates while maintaining a predetermined distance from the cooling plates, and sputters on the surface of the film on the opposite side of the cooling plates. In the manufacturing method of a magnetic recording medium in which a magnetic recording film is formed by a vapor phase deposition method such as a method, the directions of the undulations of the non-magnetic base film at the plurality of film-forming locations intersect with each other so that the undulations cancel each other out. A method of manufacturing a magnetic recording medium, comprising adjusting the guide roll.