JPH01182925A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To eliminate drop-outs and to improve durability by laminating an intermediate layer consisting of an inorg. material on a base body, smoothing the surface of the intermediate layer and laminating a thin metallic film on the base body via said layer. CONSTITUTION:The intermediate layer 13 consisting of the inorg. material having good polishability is first laminated on the nonmagnetic base body 11 usually consisting of a material having poor polishability. Coarse projections 12 are then removed from the surface of the intermediate layer 13 by a method such as burnishing to smooth the surface. The thin metallic film and a protective layer 15, etc., are laminated on the smoothed surface of the intermediate layer 13. The recording medium of the thin metallic film having the contact surface with a playback head as smooth as to prevent generation of the drop-outs is thereby produced. The drop-outs are less generated and the durability is improved if the various stages for laminating the thin metallic film and other layers are strictly controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic recording medium having a metal thin film magnetic layer.

[Conventional technology]

Conventionally, coated magnetic recording media have been widely used as hard disks and flexible disks. This coated magnetic recording medium usually has a coated layer on a substrate containing a magnetic material dispersed in a resin binder. If large protrusions exist on the surface of the medium, poor contact with the reproducing head occurs, resulting in a phenomenon in which a reproduced signal is missing, so-called dropout. In order to prevent dropouts, a so-called burnishing process is performed in which the surface of the magnetic layer or protective layer of a magnetic recording medium is polished using a fine abrasive tape or the like to remove coarse protrusions. Even if this burnish is applied directly to the surface of the magnetic layer, it rarely causes damage to the magnetic layer. This is because the coated magnetic layer uses a binder (organic polymer, etc.)
This is because by containing an organic lubricant or the like, it has lubricity sufficient to withstand burnishing.

On the other hand, in recent years, metal thin film magnetic recording media that can improve recording density have attracted attention. This recording medium is formed by forming a thin film of magnetic metal on a substrate by a method such as vapor deposition or sputtering. Metal thin films formed by these methods, unlike conventional coating-type films, do not contain a binder or lubricant that imparts lubricity, and are therefore extremely susceptible to sliding. Therefore, a protective layer having excellent durability against abrasion is usually laminated on top of the magnetic layer.

This metal thin film type magnetic recording medium may also have coarse protrusions as in the conventional coated type. The following two points are the main causes of this occurrence.

The first cause is defects on the substrate surface. In particular, when producing flexible disks using an organic polymer film as a base, components of manufacturing equipment, etc. If contact with the film cannot be avoided, and as a result there is a defect such as a scratch on the surface of the member, the defect will be transferred to the surface of the film. In addition, for the purpose of imparting slipperiness to the film, a filler is incorporated into the molten material for film formation, or the surface of the film is coated with a solution containing particles for forming irregularities.
When forming fine irregularities on the film surface, agglomeration of the filler and particles in the solution cannot be completely avoided.
The agglomerated particles induce the generation of coarse protrusions on the film, that is, defects on the substrate surface.

The second cause is the generation of coarse protrusions on the surface of the magnetic layer or protective layer due to the inclusion of impurities (dust) when the magnetic layer or protective layer is laminated by a method such as vapor deposition or sputtering.

This second cause can be significantly reduced by thoroughly controlling the various steps in forming and laminating each layer. However, it is difficult with the current technology to completely prevent the first cause, that is, the occurrence of defects on the substrate surface. Therefore, the burnishing process is indispensable in the production of metal thin film type magnetic recording media as well as in the conventional coating type.

[Problem to be solved by the invention]

When introducing a burnishing process in the production of metal thin film magnetic recording media, there were problems as described below.

When attempting to remove coarse protrusions on the surface of an organic polymer film, which is commonly used as a substrate, by performing burnishing, the film is extremely soft and viscous compared to abrasive powders such as alumina, so it is difficult to remove the rough protrusions on the surface. A finished surface may not be obtained, the film surface may be damaged, or the abrasive powder may sink into the film surface. Note that this also applies to conventional coated magnetic recording media.

Furthermore, as mentioned earlier, the magnetic layer is extremely susceptible to sliding, so if the surface is burnished, excessive polishing may occur, damaging the surface properties of the magnetic layer and causing various defects. . Therefore, attempts have been made to solve the problem of coarse protrusions by performing burnishing on the surface of the protective layer laminated on the magnetic layer. However, when the protective layer is burnished, the protective layer is scraped off at the coarse protrusion portions, which tends to cause a defect in which the magnetic layer is exposed.

When this exposed portion is rubbed by the head, abrasion powder of the magnetic layer, which usually has poor abrasion resistance, is generated, and this abrasion powder causes problems such as damage to the entire medium.

Furthermore, since it is difficult to control the contact state between the vanish wrapping member and the protective layer to a suitable state, the protective layer may be scraped off and the magnetic layer exposed even on a smooth surface without large protrusions. there were. This was particularly noticeable in burnishing of flexible disks, where the contact state is particularly difficult to control. In order to prevent the magnetic layer from being exposed on this smooth surface part, a burnishing method using a highly hard burnishing head has been proposed (TCL Research and Practical Application Report, Vol. 28, No. 1O, P.
121~), this cannot solve the above-mentioned exposure of the magnetic layer caused by the removal of the coarse protrusions.

The present invention has been made in view of the above-mentioned problems, and its purpose is to perform burnishing that is effective and does not damage the recording medium, thereby producing a metal that is free from dropouts and has sufficient durability. An object of the present invention is to provide a method for manufacturing a thin film magnetic recording medium.

[Means to solve the problem]

As stated above, the present inventors have discovered that the occurrence of coarse protrusions in the magnetic layer and protective layer can be significantly reduced by thoroughly controlling the lamination processes, and that Taking into account that it is difficult to prevent the formation of coarse protrusions on the surface of the body using conventional techniques, the present invention has been completed as a result of intensive studies to achieve the above object.

That is, the present invention provides a method for manufacturing a metal thin film magnetic recording medium that includes the step of laminating a metal thin film on a substrate, the step of laminating at least an intermediate layer made of an inorganic material on the substrate, and the step of laminating the surface of the intermediate layer. A method for manufacturing a metal thin film type magnetic recording medium, comprising a smoothing step and a step of laminating the metal thin film on the substrate via at least the intermediate layer.

More specifically, in the present invention, an intermediate layer made of an inorganic material with good polishability is first laminated on a non-magnetic substrate made of a material that usually has poor polishability, and then the surface of the intermediate layer is coated with burnishing or the like. Remove rough protrusions and smooth them using the method of
This is a method of manufacturing a metal thin film type magnetic recording medium whose contact surface with a reproducing head is smooth enough to prevent dropouts by laminating a metal thin film and other layers on the smooth surface of the intermediate layer. . In addition, in the method of the present invention, if the various steps of laminating the metal thin film and other layers are thoroughly controlled, the occurrence of dropouts can be further reduced.

FIGS. 1(a) to 1(C) are partial cross-sectional views schematically showing one aspect of the process of the present invention. Hereinafter, the present invention will be explained in detail using these drawings.

First, as shown in FIG. 1, an intermediate layer 13 made of an inorganic material is laminated on a nonmagnetic substrate 11. This non-magnetic substrate 11
There is a coarse protrusion 12 on the top due to the reasons mentioned above.

The non-magnetic substrate 11 may be appropriately selected depending on the type of recording medium to be obtained and its intended use. The effects of the present invention are particularly noticeable when an organic polymer film is used. Examples of the organic polymer film include films of polyethylene terephthalate, polyimide, aramid, polysulfone, and the like.

For the intermediate layer 13, a material is appropriately selected that has good adhesion with the layers stacked above and below it, has good polishability, and does not adversely affect the magnetic properties, flexibility, etc. of the recording medium. Just use it. Intermediate layer 13 with particularly excellent polishability
When attempting to form a metal material, it is preferable to use a metal material, for example, an Fe alloy containing Ti, P, etc., a brass-based material composition, etc. may be used. Further, when it is desired to form the intermediate layer 13 whose surface is particularly hard to be damaged, it is preferable to use an inorganic oxide material, such as 5i02, Co3
O4, TiO2, ZrO2, etc. may be used. Also,
The intermediate layer 13 having properties similar to those of inorganic oxide materials can also be formed using inorganic nitride and inorganic boride materials.

The thickness of the intermediate layer 13 may be made thicker than the height of the coarse protrusions 12. Therefore, the thickness of the intermediate layer 13 may be appropriately selected depending on the surface condition of the base 11, but it is usually 500 Å.
The thickness is preferably aOOÅ or more. Further, the intermediate layer 13 is not limited to a single layer, and a plurality of intermediate layers may be laminated. For example, it is also possible to improve the deposition rate by depositing an AI film.

The method of laminating the intermediate layer 13 on the substrate 1 includes
Depending on the material of No. 3, various film forming techniques and lamination techniques may be selected and used as appropriate, and for example, methods such as sputtering, vacuum evaporation, ion blating, and electroless plating can be used.

Next, as shown in FIG. 1(b), the surface of the intermediate layer 13 is smoothed. The surface can be smoothed by lapping tape or burnishing using a burnishing head as described above. For example, when performing vanishing using wrapping tape, a method as shown in FIG. 3 can be used. In this method, a disk 31 in which an intermediate layer is laminated on a base is burnished with a wrapping tape 32, and the residue caused by the burnishing is removed with a Japanese paper tape 33. This wrapping tape 32 and Japanese paper tape 3
3, in order to prevent deterioration of each function due to continuous use, gradually shift it in the direction of the arrow shown in the figure before use. The grade of this wrapping tape 32 is #1.
It is preferable that it is about 0,000 to #15,000.

However, the method of smoothing the surface of the intermediate layer in the present invention is not limited to the above-mentioned burnishing method, but any method that can smooth the surface depending on the material of the intermediate layer etc. , any method can be used.

Next, as shown in FIG. 1(C), a magnetic layer 14 made of a metal thin film is laminated on the intermediate layer 13, and then the magnetic layer 14 is laminated on the intermediate layer 13.
A protective layer 15 is laminated thereon to obtain a metal thin film type magnetic recording medium by the method of the present invention.

[Magnetic layer] For the material and lamination method of 4 and the material and lamination method of protective layer 15, any material and method that can be used in the manufacture of metal thin film magnetic recording media can be used, and they can be changed as desired. You can select it as appropriate. Further, if the various steps in the lamination method are thoroughly controlled to prevent the formation of coarse protrusions in these layers, a better recording medium can be obtained.

The material of the magnetic layer I4 can be, for example, a single ferromagnetic material such as Fe, Go, or Ni, or an alloy or compound thereof, and the lamination method includes, for example, plating,
Methods such as vacuum evaporation and sputtering can be used.

The protective layer 15 includes, for example, Ti, V, Cr, Go.
, Ni, Cu, Zn, Zr, Nb, Mo,
Metals such as Hf, Ta, W, Pb, and AI; semimetals such as Si and Ge; and oxides, nitrides, carbides, borides, and the like thereof can be used. As the lamination method, a thin film forming method in a vacuum such as vacuum evaporation, sputtering, ion blasting, or CVD method can be used, which is advantageous in terms of controllability of the film quality and film thickness of the protective layer 15.

Although the present invention has been described in detail above, the present invention is not limited thereto. For example, the intermediate layer 13 and the magnetic layer 14 may be laminated on both the front and back surfaces of the base 11 to prevent curling. can. Furthermore, laminating a metal thin film on an intermediate layer as used in the present invention does not mean only direct lamination, but also includes some kind of layer such as an underlayer for the purpose of controlling the growth of magnetic metal crystals. It also includes the meaning of laminating through layers. Furthermore, depending on the application, it is not necessary to laminate a protective layer.

Next, an example of an apparatus capable of laminating the intermediate layer 13, magnetic layer 14, protective layer 15, etc. in the manufacturing method of the present invention described above will be described.

FIG. 2 is a schematic diagram showing an example of an RF magnetron sputtering apparatus. This device includes a magnetron 26 surrounded by a shield 22 and an RF
The target 23 has a target 23 connected to a main power source (not shown), and the target 23 is configured to be cooled by water introduced from a cold water inlet 27, and the lower part of the target 23 is connected to the substrate via a shutter 24. 25 is installed, and a gas inlet 28 and a gas outlet 29 are connected.

Using this apparatus, the intermediate layer 13, magnetic layer 14, and protective layer 15 of the present invention can be formed under predetermined film forming conditions.

FIG. 4 is a schematic diagram showing an example of a continuous sputtering apparatus. This apparatus is for manufacturing tape-shaped magnetic recording media. In this device, an unwinding core 43, a winding core 4,
8 and free rolls 45 and 47, and a mask 42 and a target 49 connected to an RF main power source (not shown) are provided at the bottom. Note that this entire device is housed in a vacuum chamber (not shown).

Using this apparatus, the intermediate layer 13, magnetic layer 14, and protective layer 15 of the present invention can be deposited under predetermined deposition conditions to produce a tape-shaped magnetic recording medium.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 First, Tg is about 400°C, Young's modulus is about 600g/1III112, and the surface has Rmax 30
A polyimide film with a density of approximately 107/mm2 and a thickness of approximately 50 scales (
A substrate) was prepared. This polyimide film (substrate) was placed at a predetermined position within the apparatus shown in FIG.

Next, a glassy 5i02 plate was used as the target 23, Ar gas was used as the sputtering gas, and the RF power was set to 0.
．． 5 kW, a pressure of 0.5 pa, room temperature, and while introducing oxygen gas from the gas inlet 28, an Si02 film (intermediate layer) with a thickness of 2000 was formed on the polyimide film (substrate 25) by sputtering. did. The film forming rate at that time was 250 people/min. Note that the above-mentioned introduction of oxygen gas was introduced in order to prevent 0 from being liberated from Si and form an unsaturated oxide film, and to improve the polishability of the intermediate layer.

Next, the polyimide film (substrate 25) was turned over, and a film thickness of 2000 5i0 was applied to the back side in the same manner as described above.
Two films (intermediate layer) were formed to prevent curling.

Next, the film with the intermediate layer formed on both sides as described above was punched out into a circular shape with a diameter of 3.5 inches to form a disk.

Next, both sides of the punched disk were burnished using the apparatus shown in FIG. The grade of the wrapping tape 32 at that time was #I2000, the number of rotations of the isk was 90+) rpm, and the burnishing time was 10 seconds.

Next, using the apparatus shown in FIG. 2, a CoCr perpendicular magnetization film (uniform layer) having a film thickness of 0.4 scale was laminated on both surfaces of the disk. The target at that time was C0 containing 20% by weight of Cr.
A Cr alloy was used, the RF power was 0.5 kW, and the Ar pressure was 0.5 pa. In addition, the film formation rate is 800 people/
It was a minute.

When the magnetic properties of the M-layered CoCr perpendicularly magnetized film were measured as described above, it was found to be 4πMs 400 ewu/c.
c.

It was Hc”600 Oersted.

Next, using the apparatus shown in FIG. 2, a film thickness of 0.02
A p CO oxide film (protective layer) was laminated. At that time, metal Co was used as a target, the RF power was set to 0.2 kW, and reactive sputtering was performed while blowing oxygen gas onto the substrate. The Ar pressure was 0.30 pa. Further, the film forming rate was 150λ/min.

Next, perfluoropolyether (trade name Talitox) was applied to both sides of the disk on which the Go oxide film was laminated to a coating thickness of 20 mm to complete a flexible disk.

The flexible disk obtained by the method of the present invention as described above was installed in a 3.5-inch floppy disk driver, and its head output, dropout, and durability (endurance pass) were tested. Table 1 shows the results.
Shown below.

The linear recording density in the head output test was 40kB.
PI, and the track density was 135 TPI.

In addition, for dropouts, errors during recording and reproduction at the above-mentioned recording density were counted only for burst groups.

Further, durability was evaluated by the number of head sliding rotations (endurance bus) until the head output dropped by 3 dBg. As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Example 2 A CO3O4 sintered body was used instead of 5i02 as the target in the intermediate layer forming process, and the CO3 film thickness was 0.2ul.
A flexible disk was produced in the same manner as in Example 1 except that the O4 film (intermediate layer) was deposited at a deposition rate of 200 persons/min.

The head output, dropout, and durability (endurance pass) of the flexible disk were tested in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Example 3 Example 1 except that Ti was used instead of SiO□ as the target in the intermediate layer forming step, and a Ti film (intermediate layer) with a thickness of 0.2 scale was formed at a deposition rate of 700 people/min. A flexible disk was produced in the same manner as above.

The head output, dropout, and durability (endurance bus) of the flexible disk were tested in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Example 4 As a substrate, a thickness of 40 mm was used instead of a polyimide film.
A flexible disk was produced in the same manner as in Example 1, except that a 0.3 μm thick unsaturated oxide film of Co alone was formed as the magnetic layer instead of the CoCr perpendicularly magnetized film. Note that known conditions for forming the unsaturated oxide film of Co alone were used. That is, it was formed by sputtering using Go as a target and introducing an appropriate amount of oxygen gas.

Furthermore, when we measured the magnetic properties of the unsaturated oxide film, we found that 4
yrMs 480 ewu/cc, HC 850 ersted.

The head output, dropout, and durability (endurance bus) of the flexible disk were tested in the same manner as in Example 1. The results are shown in Table-■.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Example 5 As a substrate, a thickness of 40 mm was used instead of a polyimide film.
A flexible disk was produced in the same manner as in Example 3 except that μ PET film was used.

The head output, dropout, and durability (endurance bus) of the flexible disk were tested in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Example 6 A PET film having a thickness of 40 scales was placed in the apparatus shown in FIG. 2, and a SiO□ film (intermediate layer) having a thickness of 0.2 bars was formed on both sides of the film by sputtering. The film forming conditions at that time were the same as in Example 1.

Next, a 3.5-inch disk was formed in the same manner as in Example 1, and the disk was burnished.

Next, using the apparatus shown in FIG. 2, a 0.5-thick FeNi film (permalloy) (fIIi layer) was laminated on both surfaces of the disk. The target at that time is Fe 80%
An alloy target with a 20% Ni composition was used, the RF power was 1.0 kW, and the Ar pressure was 0.6 pa.

Next, using the apparatus shown in FIG. 2, a CoCr perpendicular magnetization film having a thickness of 0.2 μm was laminated on both sides of the disk on which the FeNi layer was laminated. The film forming conditions at that time were the same as in Example 1.

Next, a protective layer and perfluoropolyether were laminated and coated in the same manner as in Example 1 to complete a flexible disk.

The head output, dropout, and durability (endurance bus) of the flexible disk were tested in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Example 7 A 5i02 film (intermediate layer) having a thickness of 1500 was formed on both sides of the same polyimide film as used in Example 1 using the apparatus shown in FIG. The film forming conditions at that time were the same as in Example 1.

Next, a 3.5-inch disk was formed in the same manner as in Example 1, and the disk was burnished.

Next, using the apparatus shown in FIG. 2, a Cr film (base layer) having a thickness of 2000 was laminated on both surfaces of the disk. A metal Cr target was used as the target at that time, the RF power was 1.0 kW, and the Ar pressure was 0.5 pa. Further, the film forming rate was 800 people/min.

Note that this underlayer is provided to improve crystal growth of the magnetic layer.

Next, using the apparatus shown in FIG. 2, CoNiCr layers (magnetic layers) having a thickness of 500 layers were laminated on both surfaces of the disk.

At that time, the target was (composition ratio of (:oNiCr) (:
o 80 Ni 13 Cr 7) Using an alloy, R
The F power was 0.5 kW, and the Ar pressure was 0.5 pa.

When the magnetic properties of the CoNiCr layer laminated as described above were measured, it was found that an in-plane magnetization film with H″c=about 750 microns was sufficient.

Next, the CoNiCr layer was deposited on both sides of the disk using the apparatus shown in FIG.
o301 layer (protective layer) was laminated. At that time, metal Go was used as the target, reactive sputtering was performed, and RF
The power was 0.5kw, and the pressure was 0.4pa.

Next, perfluoropolyether was applied in the same manner as in Example 1 to complete a flexible disk. The head output, dropout, and durability (endurance pass) of the flexible disk were tested in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Comparative Example 1 No intermediate layer was formed and the vanish was made of polyimide film (
A flexible disk was manufactured in exactly the same manner as in Example 1 except that the process was performed directly on the substrate), and its head output, dropout, and durability (endurance pass) were evaluated as in Example 1.
Tested in the same manner. The results are shown in Table-1.

As is clear from the results shown in Table 1, the flexible disk obtained by the method of this comparative example had many dropouts, poor head output, and insufficient durability.

In this comparative example, when the surface of the substrate was observed under a microscope immediately after the substrate was burnished, numerous scratches caused by the burnishing and adhesion of shavings were confirmed. Therefore, it can be inferred that various properties of the flexible disk according to this comparative example are deteriorated due to the poor polishability of such a base (polyimide film).

Comparative Example 2 No intermediate layer was formed and the vanish was made of polyimide film (
A flexible disk was manufactured in exactly the same manner as in Example 3 except that the process was performed directly on the substrate), and its head output, dropout, and durability (durability pass) were compared with Example 1.
Tested in the same manner. The results are shown in Table-1.

The results were similar to those of Comparative Example 1.

Comparative Example 3 A flexible disk was produced in exactly the same manner as in Example 4, except that no intermediate layer was formed and burnishing was performed directly on the PET film (substrate), and its head output, dropout, and durability (endurance pass) were prepared. The test was conducted in the same manner as in Example 1.

The results are shown in Table-1.

The results were similar to those of Comparative Example 1.

Comparative Example 4 A flexible disk was produced in exactly the same manner as in Example 1 except that the intermediate layer was not burnished and the protective layer was burnished instead, and its head output, dropout, and durability (endurance pass) were manufactured. The test was conducted in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, the flexible disk obtained in this comparative example has improved dropout and head output compared to Comparative Examples 1 to 3, but durability is still insufficient. . The cause of this is thought to be that when the top surface of the protective layer is burnished, the protective layer falls off in the areas where the coarse protrusions are removed, exposing the magnetic layer, and that a large amount of shallow damage occurs on the entire disk surface. Ru.

Comparative Example 5 A flexible disk was produced in exactly the same manner as in Example 7 except that the intermediate layer was not burnished and the protective layer was burnished instead, and its head output, dropout, and durability (durable bus) were measured. The test was conducted in the same manner as in Example 1. The results are shown in Table-1.

As is clear from the results shown in Table 1, the flexible disk obtained in this comparative example did not have sufficient head output because the protective layer was directly burnished, which damaged the medium surface and made it difficult to obtain a good rad touch. It's not something.

Example 8 Using the apparatus shown in FIG.
Two films (intermediate layer) were formed. At that time, 5i02 glass was used for the target 49, and the RF power was 0.5 people w, A
Oxygen gas was introduced at an r pressure of 0.5 pa.

Next, the tape with the 5i02 film formed thereon was cut into 1/2 inch width.

Next, the wrapping tape 3 in the apparatus shown in FIG.
Remove 2 and replace it with 17 obtained as above.
A tape 32 having a width of 2 inches was installed, and at the same time, the flexible disk 31 was removed, and a wrapping tape 32 punched into a disk shape was placed in its place. This wrapping sheet 32 is rotated at 900 rpm, and the tape 3
Banish was performed while sending 2 at a speed of 2fflZ. The grade of the wrapping sheet at that time is #1500
0, and the thickness was 40p.

Next, using the device shown in FIG.
A CoCr film (with a thickness of 0.3 mm) is placed on the i02 film (intermediate layer).
A magnetic layer (-) was continuously formed. At that time, Goer alloy is used for the target 49, and the surface temperature of the can 46 is approximately 15
The temperature was 0° C., and the tape transport speed was 6 cm/min.

When the magnetic properties of the Go(:r film) formed as described above were measured, it was found that 4yrMs"400 ewu/cc%
Hc Police 1000 oersted).

Next, on the CoCr film (magnetic layer), a Co3O4 film (protective layer) having a thickness of 100 was formed using the apparatus shown in FIG. At that time, the target 49 is Co3O
4 sintered body, a small amount of 02 from a gas introduction system (not shown)
This was done while introducing gas. It was confirmed that the obtained film had a clear Go304 diffraction peak.

Next, perfluoropolyether was applied to both sides of the tape on which the (:o304 film was laminated) using a dip coater so that the dry coating thickness was 7 g, thereby completing a magnetic tape.

The magnetic tape obtained by the method of the present invention as described above was installed in a home 172-inch VHS system VTR, and its head output, dropout, and durability (endurance bus) were measured.
was tested. The results are shown in Table-1.

In addition, in the head output test, commercially available Go-γFe
2O3 tape is Ode, dropout is 16dB
Dropout was defined as a period in which a drop in output continued for 15 μs or more. In addition, durability was determined by repeated running durability and the number of durability buses until the initial output dropped by 3 dB.

As is clear from the results shown in Table 1, it was confirmed that the flexible disk obtained by the method of this example had little dropout, good head output, and excellent durability.

Comparative Example 6 A magnetic tape was produced in the same manner as in Example 8, except that no intermediate layer was formed, the vanish was not applied directly to the polyimide film tape (substrate), and a cutting process of 172 inch width was performed after forming the protective layer. The head output, dropout, and durability (durability pass) were tested in the same manner as in Example 8.

The results are shown in Table-1.

As is clear from the results shown in Table 1, the magnetic tape obtained in this comparative example had many dropouts, poor head output, and insufficient durability.

〔Effect of the invention〕

As explained above, according to the method of the present invention, an intermediate layer with good polishability is laminated on a substrate and burnished, etc., so that defects caused by coarse protrusions that inevitably occur on the surface of the substrate are eliminated. It is possible to manufacture a metal thin film type magnetic recording medium having a protective layer in which the problem is solved and the protective layer is in a good laminated state.

Such magnetic recording media have excellent head output, durability, and have little dropout. Therefore, it is a useful magnetic recording medium for various uses such as audio, DAT, computer memory, and VTR.

[Brief explanation of the drawing]

FIGS. 1(a) to (C) are partial cross-sectional views schematically showing one aspect of the process of the method of the present invention, and FIGS. 2 and 4 illustrate an apparatus that can be used in the method of the present invention. The schematic diagram, FIG. 3, is a diagram illustrating a vanishing method. 11...Base 12...Large protrusion 13--Intermediate layer 14--Magnetic layer 15--Protective layer 21--Vacuum chamber 23--Target 25--Substrate 31--Flexible disk, wrapping tape 3
2-...Wrapping tape, film tape 33-...
Washi tape 44--Base film 46--Can 49--Target

Claims (1)

[Claims] A method for manufacturing a metal thin film magnetic recording medium including the step of laminating a metal thin film on a substrate, comprising the steps of laminating at least an intermediate layer made of an inorganic material on the substrate, and smoothing the surface of the intermediate layer. A method for manufacturing a metal thin film type magnetic recording medium, comprising the steps of: laminating the metal thin film on the substrate via at least the intermediate layer.