JPS62275322A - Production of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a vertically anisotropic magnetic film having high coercive force in the direction perpendicular to the vertically anisotropic magnetic field and film plane by treating the surface of a Ti film, which is formed by a vacuum deposition method on a substrate, by the particles from an ion gun, then forming a vertically anisotropic magnetic film essentially consisting of Co and Cr on the Ti film by a vacuum deposition method. CONSTITUTION:A polyimide film is run in the direction opposite from an arrow 7 and the Ti film is formed to 200Angstrom film thickness thereon. The evaporating material in a vapor source 6 is then changed to a Co-Cr alloy and the polyimide film deposited with the Ti film by evaporation is run in the direction of the arrow 7 and the vertically anisotropic magnetic Co-Cr film is formed to 25000Angstrom thickness thereon. A Kaufman type ion gun is used and the acceleration voltage of the ion gun is specified to -KV and the ion current density to 0.8mA/cm<2>. Ar is used for the gas to be introduced into the ion gun. The traveling speed of the substrate is specified to 15m/min, the deposition rate of the film to 9000Angstrom /sec and the temp. Tcan on the peripheral face of a cylindrical can to 200 deg.C and 270 deg.C.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a method of manufacturing a perpendicular magnetic recording medium having excellent high-density recording characteristics.

2. Description of the Related Art A perpendicular magnetic recording system is known as a magnetic recording system with excellent short wavelength recording characteristics. This method requires a perpendicular magnetic recording medium having perpendicular magnetic anisotropy. When a signal is recorded on such a medium, the residual magnetization is oriented in a direction perpendicular to the film surface of the medium, and therefore, the shorter the signal wavelength, the smaller the demagnetizing field within the medium, and the higher the reproduction output.

Perpendicular magnetic recording media commonly used today are perpendicular magnetic anisotropic recording media mainly composed of CO and Or. A magnetic layer having a magnetic property is formed by a sputtering method. Sputtered films containing Go and Or as main components have a crystalline system with a close-packed hexagonal structure when the amount of Or is 30% by weight or less, and the C axis can be oriented perpendicular to the film surface. Therefore, a perpendicular magnetic anisotropic film can be realized.

However, since the sputtering method is slow in forming a magnetic thin film, it is difficult to produce a perpendicularly magnetized film at low cost. In contrast to the sputtering method, the vacuum evaporation method (including methods that ionize some of the evaporated atoms, such as the ion blating method) can achieve Co-Gr perpendicular magnetic anisotropy at a high film deposition rate of several thousand people/second. A sexual membrane is obtained. In the vacuum evaporation method, a tape-shaped perpendicular magnetic recording medium can be obtained with high productivity by forming a thin film while moving the substrate along the circumferential surface of a cylindrical can. The figure schematically shows the internal structure of such a vacuum evaporation device.

A substrate 1 made of a polymeric material runs along the circumferential surface of a cylindrical can 2 in the direction of an arrow 7. A mask 5 is arranged between the evaporation source 6 and the cylindrical can 2, and the evaporated atoms adhere to the substrate 1 through the opening 12 of this mask. 3
．． 4 are a supply roll and a take-up roll for the substrate 1, respectively. Since 8 and 9 are symbols related to the present invention, they will be explained later.

10.11 will also be described later. Note that 8 is an ion gun, which is not installed in conventional equipment.

Problems to be Solved by the Invention In order for the Go-Cr perpendicular magnetic anisotropic film to have excellent short wavelength recording and reproducing characteristics, it is preferable that the perpendicular anisotropic magnetic field H1 is large. However, conventionally, when a Go-Cr perpendicular magnetic anisotropy film is directly fabricated on a substrate made of a polymer material using a vacuum evaporation apparatus as shown in the figure, the H, of the film is at most 4 KOf5.
and Co-0r prepared by sputtering method.
This is lower than the 6-e KOe of the perpendicular magnetic anisotropic film. In order to increase H, it is known that it is effective to deposit a Co--Cr film on a substrate made of a polymer material via a Ti deposited film. However, the surface of the Ti film is extremely easily oxidized. Go-Cr on one film without progressing to oxidation
Although large H, can be obtained by depositing the film, oxidized T
The Co—Cr film on the i film has a small H content. Furthermore, in order to obtain a high reproduction output, it is necessary to increase the coercive force Hc in the direction perpendicular to the film surface of the Co-0r film. The higher the substrate temperature during vapor deposition, the larger the Hc soil becomes.

However, in order to form a Go-Cr film with a large amount of KHcl on a substrate on which a Ti evaporated film has been formed, when the temperature of the cylindrical can is increased in a vacuum evaporation apparatus as shown in the figure, the inside of the vacuum chamber is heated to about 10 Torr. Even if the vacuum level is maintained at a vacuum level of
! It is difficult to increase the That is, conventionally, it has been difficult to fabricate a large Go-Cr film on both J+Hc using a vacuum evaporation method.

Means for Solving the Problem After the surface of a Ti film formed on a substrate by vacuum evaporation is treated with particles from an ion gun, perpendicular magnetic anisotropy mainly composed of Co and Or is deposited on the Ti film. A transparent film is formed by a vacuum evaporation method.

When the Ti deposited film surface is treated with particles from a working ion gun, the oxide layer on the surface is removed and a perpendicular magnetic anisotropic film with high H and H, soil is obtained.

EXAMPLE The present invention will be explained by way of a specific example. The figure shows an example of the internal configuration of a vacuum evaporation apparatus for carrying out the present invention. In the figure, the parts other than 8 to 11 are as already explained in the section of the prior art. Note that a Ti vapor deposited film is formed on the surface of the substrate 10 made of a polymeric material, that is, the surface on which the Go-Cr film is deposited. 8 is an ion gun similar to those used in ion beam sputtering, ion milling, etc. Particles emitted from the ion gun 8 fly in the direction of the arrow 9 and collide with the substrate 1 made of a polymeric material and having a Ti film formed on its surface.

Atoms evaporated from the evaporation source 6 adhere to the substrate whose surface has been treated in this manner, forming a Go--Cr film.

Using the vacuum evaporation apparatus shown in the figure, first, using Ti as the evaporation material in the evaporation source θ, a polyimide film with a thickness of 12 μm is run in the direction opposite to the arrow 7 in the figure to form a Ti film with a thickness of 200 μm. do. Next, the evaporation material in the evaporation source e is
A polyimide film on which the Or gold alloy was changed and a Ti film was vapor-deposited was run in the direction of arrow 7 in the figure to obtain a film thickness of 250°.
The effects of the present invention when a Co--Cr perpendicular magnetic anisotropy film was formed are shown in the table. The ion gun used was a Kaufmann type, the accelerating voltage of the ion gun was -1 KV, the ion current density was 0.8 mm/crl, and the gas introduced into the ion gun was mr.

The running speed of the substrate is 15 m/min, and the film deposition rate is 9000 people/min.
Second 9 Temperature 'raan' of the circumferential surface of the cylindrical gear 7 is 200'C
and 270'C.

From the table, when T02Ln"200'C is used and a Go-Cr film is deposited without treatment with an ion gun, H, H, and H discharges are 4 KOe and 4000 s, respectively, but when treated with an ion gun, H No change, but HK is 5KOe
It can be seen that this has been improved. In order to obtain a high playback output, it is possible to increase the HC by increasing the 'rcan, but if you simply increase the 'rcan as in the past, the TC&n=27Q'C column of the table As you can see, the Hc is about 70006, but the HK is 2.5.
The KOe will be low.

If HK is low, high reproduction output cannot be obtained in the short wavelength region.

On the other hand, if a Go-Cr film is formed after treating the surface of the T1 deposited film with an ion gun, TQ&n=270
'In C l(, = s, 7xoe, on Ha = 8
5006, a perpendicular magnetic anisotropy film with very excellent characteristics can be obtained. The following is considered to be the reason why the effect of the present invention is particularly noticeable when 'I'can is high. When a -Cr film is deposited using an apparatus like the one shown in the figure, without the conventional ion gun treatment,
Especially when the temperature TO&n of the cylindrical can phase is high,
Oxidation of the T1 film surface progresses between the part 1o where the film starts to come into contact with the can and the vapor deposition part 11 due to the oxygen in the residual gas remaining in the vacuum chamber, and as a result, the H of the Go-Or film is
.

will decrease. On the other hand, it is thought that when the Ti film surface is treated with an ion gun, the oxidized layer on the surface is etched, thereby improving the HK. Incidentally, since H[ is improved for this reason, it is desirable that the treatment with the ion gun be performed in the vicinity of the vapor deposition section 11.

In the above example, the acceleration voltage of the ion gun was -1 KV and the ion current density was 0.8 mm/d. , ammu/citD range, the same results as above were obtained.

Furthermore, whether or not the neutralizer attached to the ion gun was in operation did not affect the effectiveness.

The substrate is not polyimide film, but polyamide film or polyetherimide film.

The same results as above were obtained even when polyethylene naphthalate film or the like was used.

In addition, although an example of a perpendicular magnetic anisotropic film containing CO and Cr as main components has been described above, a completely similar ion gun A treatment effect was seen.

Effects of the Invention According to the present invention, a film with high perpendicular magnetic anisotropy in the perpendicular anisotropic magnetic field H and in the coercive force Hc in the direction perpendicular to the film surface can be obtained with extremely excellent productivity by a vacuum evaporation method. .

[Brief explanation of the drawing]

The figure is a diagram schematically showing the inside of a vacuum evaporation apparatus used in an embodiment of the present invention. 1...Substrate made of polymeric material, 2...
・Cylindrical can, 3... Supply roll, 4... Curved winding roll, 5... Mask, 6...
Evaporation source, 8...Ion gun.

Claims (1)

[Claims] After treating the surface of a Ti film formed on a substrate by a vacuum evaporation method with particles from an ion gun, a perpendicular magnetic anisotropic film containing Co and Cr or Co, Cr and Ni as main components is formed on the Ti film. 1. A method for manufacturing a perpendicular magnetic recording medium, the method comprising: forming a perpendicular magnetic recording medium by a vacuum evaporation method.