JPS63237207A - Manufacturing method of perpendicular magnetic recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a perpendicular magnetic recording medium made of a Co--Cr--W--C alloy film having excellent wear resistance.

[Prior art and its problems]

It is known that perpendicular magnetic recording media made of sputtered Co-Cr alloys are excellent as high-density magnetic recording media. However, when a Co--Cr alloy layer is used as a magnetic recording medium, there is a problem that it has a large frictional resistance with a magnetic head, is easily subject to wear and damage, and lacks durability.

For this reason, it is possible to provide a wear-resistant or lubricating protective layer on the magnetic metal thin film.
Materials such as metal oxides have been tried. However, in high-density recording that requires perpendicular magnetic recording, the thickness of the protective layer becomes a problem.

That is, when a protective layer is provided, the spacing between the head and the medium increases, resulting in a decrease in output. Therefore, the thickness of the protective layer must be at most 500 Å or less, and in order to avoid spacing loss, it is necessary to limit the number of people to approximately 30 or less.From the viewpoint of wear resistance, the thickness of the protective layer must be sufficiently thick. It is extremely difficult to sufficiently improve the wear resistance with such a thickness.To solve this problem, it is necessary to improve the wear resistance of the magnetized film itself.One way to do this is to improve the wear resistance of the magnetic film itself. As a method, a thin film of an alloy consisting of C01CrSW and C is used as a magnetization film.

Methods for producing this alloy thin film by sputtering include (1) producing a sputtering target made of a quaternary alloy of Co-Cr-W-C and performing sputtering, or (2) sputtering a sputtering target of each element. It is conceivable to perform sputtering by a combination of so-called composite target methods.

In the above method, the carbon content is particularly important, and the physical properties of the formed thin film are subtly influenced by the carbon content in the film. Therefore, it is necessary to control the amount of carbon in the sputtering.

That is, the alloy target method (1) requires the precise and complicated work of producing a Co--Cr--W--C quaternary alloy target whose carbon content is strictly defined. Further, in the composite target method (2), a problem arises in that it is difficult to uniformly mix carbon into the film. Furthermore, as a method of mixing carbon, a method of mixing a carbon compound gas into the sputtering gas can be considered, but since elements such as hydrogen or oxygen are mixed in with the sputtering gas, it is difficult to obtain a good film.

[Means for solving problems]

The present invention is intended to solve these problems, and it is possible to deposit Co, C, etc. on a substrate of a polymer molded product containing carbon or metal carbide.
Co- characterized by sputtering r and W
The present invention relates to a method of manufacturing a perpendicular magnetic recording medium made of a Cr--W--C alloy film.

In the sputtering method of the present invention, Co, Cr and W may be simultaneously sputtered onto a substrate of a polymer molded material containing carbon or metal carbide by a composite target method, or a Co-Cr-W alloy may be sputtered. Sputtering may also be performed using a target.

According to the method of the present invention, a perpendicular magnetic recording medium with excellent wear resistance can be obtained by stably incorporating a small amount of carbon into the magnetized film. In the sputtering method, a thin film is formed on a substrate by sputtering target atoms in a plasma atmosphere. At this time, the surface of the substrate is also bombarded by atoms, and it is thought that a phenomenon similar to sputtering occurs to some extent. . The present invention utilizes this phenomenon, and is characterized in that carbon or carbide mixed into the substrate is sputtered to mix carbon into the magnetized film.

Examples of carbon used in the present invention include carbon black and graphite, and examples of metal carbides include titanium carbide, silicon carbide, aluminum carbide, zircotium carbide, chromium carbide, tungsten carbide, and iron carbide. The most preferable shape is powder, but other shapes are also possible. The amount of metal carbide used is preferably 1 to 20 wt% based on the polymer molded product.

Examples of the polymer molded product used in the present invention include polyimide and polyester.

The composition of the Co-Cr, -W-C alloy film is preferably Co
The content is 50 to 84 at%, the Cr content is 15 to 35 at%, the W content is 1 to 10 at%, and the C content is 0.1 to 35 at%.
It is 5 atom%.

〔Example〕

EXAMPLES The present invention will be explained in more detail by showing Examples and Comparative Examples below.

Example 1 5 wt % of carbon black powder with an average particle size of 0.03 μm was mixed into a polyimide monomer solution consisting of dicarboxylic acid anhydride and diamine, and after casting on a glass substrate, an imidization reaction was performed to form a solution with a thickness of about 50 μm. A polyimide film was created. Using this as a substrate, a thin film A of Go-Cr-W-C alloy (Cr content: 28 atomic %, W content: 2 atomic %) having a thickness of approximately 0.3 pm was sputtered on its surface under the following sputtering conditions. , C content 2.0 at%, remaining C
o) was formed.

Sputtering condition equipment Magnetron type high frequency sputtering equipment (two-pole parallel plate type) Target Co-Cr-W alloy (28 atomic% Cr
, 2 atomic% W) Diameter 6 inches Thickness 5 mm Sputtering gas Ar Pressure 0.5 Pa Pretreatment of a substrate Sputtering power 1 at 380''C in vacuum for 2 hours
．． 5kV 60m1n sputtering substrate temperature Water cooling Example 2 The polyimide monomer solution used in Example 1 had an average particle size of 0.
．． A polyimide film was prepared in the same manner as in Example 1 except that 5 wt % of silicon carbide powder with a diameter of 0.05 μm was mixed therein. Using this as a substrate, a 0.3 μm thick thin film B (Cr content: 28 at%, W content: 2 at%, C content: 1.5 at%, remainder Co) was created in the same manner as in Example 1. .

Comparative Example 1 A thin film C (Co
Content 70 at%, Cr content 28 at%, W content 2
%) was formed.

FIG. 1 shows the results of analyzing the carbon distribution state in each magnetized film obtained in Example 1, Example 2, and Comparative Example 1 by secondary ion mass spectrometry. In the case of a substrate containing carbon black and silicon carbide, the amount of carbon in the magnetized film near the substrate is similar to that in the substrate, and the amount gradually decreases as it approaches the surface, but it is distributed near the surface. , Co-
It can be seen that a Cr-W-C alloy is produced.

The above sample was processed into a 5.25-inch floppy disk, and FIG. 2 shows the change in output when it was placed in a floppy disk tester and brought into contact with a VTR ring head. It can be seen that the output decrease is small due to the formation of the Co-Cr-W-C alloy, and the wear resistance is excellent.

[Effects of the Invention] According to the method of the present invention, it is possible to obtain a perpendicular magnetic recording medium with excellent wear resistance in which a trace amount of carbon is stably and simply mixed into the magnetized film.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the results of analyzing the carbon distribution state in each magnetized film obtained in Example 1, Example 2, and Comparative Example 1 by secondary ion mass spectrometry. Figure 2 shows the output when each magnetized film obtained in Example 1, Example 2, and Comparative Example 1 was processed into a 5.25-inch floppy disk, and the floppy disk was placed in a floppy disk tester and a VTR ring head was brought into contact with it. FIG. Fig. 1 Kyocho etching “” Gin F, “l + (Nedaji Fig. 2

Claims (1)

[Claims] A method for manufacturing a perpendicular magnetic recording medium made of a Co-Cr-W-C alloy film, which comprises sputtering Co, Cr and W onto a substrate of a polymer molded material containing carbon or metal carbide.