JPH0448437A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the coercive force and anisotropy in the circumferential direction of a disk and to improve reproduction output and recording density, etc., by using a mixture gas of Ar and hydrogen in the process of inverse sputtering of a substrate and Cr film. CONSTITUTION:In the production process of thin film medium comprising a Cr base film and CoCrTa or CoNiCr magnetic film on a substrate by sputtering, inverse sputtering of the substrate and Cr base film is carried out in an environment of a mixture gas comprising Ar and hydrogen. The hydrogen gas to be added can chemically remove oxides which exist on the substrate and on the surface of the Cr film and cause deterioration of magnetic characteristics. Thereby, with addition of hydrogen gas, the obtd. medium has higher coercive force and anisotropy along the circumferential direction of the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a magnetic recording medium, and more particularly, to a method of manufacturing a longitudinal thin film medium for a hard magnetic disk.

[Prior Art] As a high recording density medium for hard magnetic disks, thin film media produced by sputtering have now become mainstream instead of coated media. In order to achieve high recording density, this thin film medium is required to have high output and high recording density characteristics. To improve these properties, the magnetic properties of the medium should be
It is necessary to have a large coercive force, a large squareness ratio, and a large anisotropy in the circumferential direction of the disk.

Therefore, in order to obtain the above characteristics, a NiP/Al substrate with textured grooves in the circumferential direction of the disk was used as the substrate.
After etching the surface of the substrate by reverse sputtering with Ar gas, a Cr film is formed as a base film, and then Cr11 is etched on the surface by reverse sputtering again, followed by C as a magnetic film.
A method of manufacturing a medium by forming a 0NiCr film or a CoCrTa film has been proposed (IEICE technical research report, CPM88-91 and CPMB8-92.19
1988>

[Problem to be Solved by the Invention J Even in the conventional thin film medium manufacturing technology using the sputtering method described above, the coercive force, squareness ratio, and anisotropy in the circumferential direction of the medium are at a good level. It is necessary to improve them in order to realize recording density.

Another object of the present invention is to provide a method for manufacturing a magnetic recording medium that improves the coercive force of the medium and the anisotropy in the circumferential direction of the disk in order to realize ultra-high recording density.

[Means for Solving the Problems] The present invention provides a method for manufacturing a magnetic recording medium in which a thin film medium consisting of a Cr base film and a CoCrTa or CON i Qr magnetic film is manufactured on a substrate by sputtering.
After etching the surface of the substrate by reverse sputtering in an atmosphere of a mixed gas of Ar gas and hydrogen gas, a step of forming a base film of Or, and etching the Cr film in an atmosphere of a mixed gas of Ar gas and hydrogen gas. After etching the surface by reverse sputtering, CoCrTa or C
This method of manufacturing a magnetic recording medium is characterized by comprising a step of forming a magnetic film made of oNiCr.

[Function] In the present invention, when producing a thin film medium consisting of a Cr base film and a CoCrTa or CON r cr magnetic film on a substrate by sputtering, Ar gas and hydrogen gas are used during reverse sputtering of the substrate and Or base film. The atmosphere is a mixed gas consisting of: The hydrogen gas added here can remove oxides on the surfaces of the substrate and Cr film, which cause deterioration of magnetic properties, by utilizing a chemical reaction. the result,
Due to the influence of the added hydrogen gas, it is possible to create a medium with even higher coercive force and anisotropy in the circumferential direction of the disk.

[Example] Examples of the present invention will be described below.

Example 1 In this example, a case where the magnetic film is a CoCrTa film will be described. The sputtering apparatus used in this example is of the RF magnetron type. The target was a 3N Cr target for the base film, and a CoCrTa (CoCrTa) target for the magnetic film.
12 at% Cr and 2 at% Ta>alloy targets were used, respectively. In addition, a N i P/Affi substrate with textured grooves (surface roughness Rmax = 400 people) was used as the substrate.

First, Table 1 shows sputtering conditions according to Example 1 of the present invention. In addition, for comparison, the board and C
Comparative Example 1 is a medium manufactured under the same conditions as in Table 1, except that pure Ar gas was used during the reverse sputtering of the R film.
SM). The results are shown in Table 2. From this, it was found that the medium of this example had improved magnetic properties, particularly coercive force and anisotropy in the circumferential direction of the disk, compared to conventional media.

Table 1 (blank below) Table 2 shows that the magnetic properties, particularly the coercive force and the anisotropy in the circumferential direction of the disk, are improved compared to the conventional method.

Table 3 Example 2 Next, a case where the magnetic film is a CON i Cr film will be described.

For magnetic film TCON i Cr (20at%N10
The base film target and substrate were the same as in Example 1, except that an alloy target (at%Cr) was used. In addition, as shown in Table 3, the sputtering conditions are C0N
It was the same as Example 1 except for iCr. For comparison, Comparative Example 2 is a medium fabricated under the same conditions as in Table 3, except that pure Ar gas was used during reverse sputtering of the substrate and Cr film as in the past. Properties were measured by VSM. The results are shown in Table 4. From now on, the medium of this example is the same as Example 1 (the following is a blank space) Table 4 [Effects of the invention] The magnetic recording medium manufactured by the manufacturing method of the present invention has Ar and hydrogen during reverse sputtering of the substrate and Cr film. By using the mixed gas, the magnetic properties, especially the coercive force and the anisotropy in the circumferential direction of the disk, were improved compared to the conventional method, and the reproduction output, recording density, etc. were further improved compared to the conventional method.

Claims (1)

[Claims] (1) A Cr base film and a Co base film are formed on the substrate by sputtering.
In a method for manufacturing a magnetic recording medium, in which a thin film medium made of a magnetic film of CrTa or CoNiCr is manufactured, the surface of the substrate is etched by reverse sputtering in an atmosphere of a mixed gas of Ar gas and hydrogen gas, and then a base film made of Cr is etched. After etching the surface of the Cr film by reverse sputtering using a mixed gas of Ar gas and hydrogen gas as an atmosphere, CoCrTa or CoNiC
1. A method of manufacturing a magnetic recording medium, comprising the step of forming a magnetic film made of r.