JPH03192521A - Production of thin film magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain such a medium which has little variation of surface roughness and realizes traveling of a magnetic head at super-low floating height by drying a nonmagnetic substrate after washing in a manner that the substrate is dried at usual temp. while rotating the substrate so as to utilize centrifugal force. CONSTITUTION:A nonmagnetic substrate 2 after precisely washed is mounted on a variable-speed spindle 1, and treated for finish washing by injecting a finish washing agent (e.g. pure water) while slowly rotating the substrate in the direction shown by the arrow A in the figure. Then, the substrate is fast rotated and completely dried, and detached from the spindle 1. By this method, a film formed by sputtering on the substrate can have fine projections uniformly and stably distributed thereon. Thus, variation of surface roughness of the medium due to various distribution of fine projections can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a thin film magnetic recording medium applied to a fixed magnetic disk device used as an external storage device of an information processing device such as a computer.

[Conventional technology]

A thin film magnetic recording medium (hereinafter also simply referred to as a medium) is -
For boat fishing, M alloy substrate with specified parallelism.

The flatness is finished to a surface roughness of 1, an N1-P alloy layer is formed on the surface by electroless plating, and the surface of this N1-P alloy layer is polished to the required uniform roughness to make a nonmagnetic substrate. After precision cleaning the surface of the non-magnetic substrate with a solvent, surfactant, pure water, etc., IPA (is.

-propylalcoho1), freon-11
3 (manufactured by DuPont; 1, 1. 2-trichloro
-1,2,2-trifluor.

Steam immersion cleaning and drying is performed using a fluorine-containing hydrocarbon solvent such as -ethane), and then sputtering is applied to a Cr underlayer to strengthen the magnetism, a Co alloy layer as a magnetic layer,
It is manufactured by sequentially depositing a-C layers as protective lubricant layers. Fixed magnetic disk devices usually use CSS (
Contact 5tart 5top) method is adopted, so the medium surface is appropriately finely patterned so that the magnetic head can run stably at a low flying height, and the coefficient of friction is small to ensure smooth sliding with the magnetic head. A rough surface shape is required.

[Problem to be solved by the invention]

However, in a medium manufactured using a conventional manufacturing method, when an extremely low flying height of the magnetic head (for example, 0.12 μm in terms of flying height) is required to obtain high recording density,
There is a problem in that the surface roughness of the medium varies too much, and the magnetic head does not have suitable sliding characteristics.

The present invention solves the above-mentioned problems and provides a thin film magnetic recording medium having a surface with suitable magnetic head sliding characteristics that have little variation in surface roughness and enable the magnetic head to run stably at an extremely low flying height. The objective is to provide a manufacturing method for.

[Means to solve the problem]

According to the present invention, the above problem can be solved by cleaning and drying a non-magnetic substrate processed to a desired surface roughness, and then sputtering a non-magnetic metal base layer, a magnetic layer, a protective lubricant, etc. onto this non-magnetic substrate by sputtering. In a method for manufacturing a thin film magnetic recording medium in which layers are sequentially deposited, the problem can be solved by using a manufacturing method in which drying is performed at room temperature by rotating a nonmagnetic substrate and utilizing the centrifugal force generated at that time.

[Effect]

The surface roughness of the medium is determined based on the surface roughness of the nonmagnetic substrate, and is determined by the addition of surface microprotrusions formed as a result of forming each layer necessary to constitute the medium by sputtering.

In the conventional manufacturing method, drying of the non-magnetic substrate before sputtering film formation is carried out using IPA (boiling point approximately 70°C), Freon-113.
(boiling point: about 47°C), etc., and drying was carried out at a considerably high temperature. As a result, abnormal crystal growth occurs during sputter deposition during deposition of the non-magnetic metal underlayer, which prevents the formation of fine and uniform surface microprotrusions, increasing variations in the surface roughness of the media. .

By drying this nonmagnetic substrate at room temperature, fine, uniform, and stable surface microprotrusions are formed by sputtering film formation, and variations in the surface roughness of the medium due to variations in surface microprotrusions are eliminated. It can be suppressed. Therefore, the surface roughness of the medium can be precisely controlled by the surface roughness of the non-magnetic substrate, and by processing the non-magnetic substrate to an appropriate surface roughness, a surface with appropriate magnetic head sliding characteristics can be created. It becomes possible to obtain a medium that is

Moreover, by using centrifugal force to dry at room temperature, the problem that drying time becomes longer when changing from high temperature drying to room temperature drying is also solved.

〔Example〕

FIG. 1 is a conceptual diagram of an embodiment of the drying method of the present invention, with FIG. 1(a) being a bottom view and FIG. 111A(c) being a side view. The precision-cleaned non-magnetic substrate 2 mounted on the variable speed spindle 1 is rotated at low speed in the direction of arrow A (for example, 11
Final cleaning is performed by injecting a pre-drying cleaning liquid (e.g. pure water) from the nozzle 3 while the rotation speed is 00 rpm, and then the rotation is switched to high speed (e.g. 3000 rpm) and rotated until completely dry. Remove from l.

An A1 alloy substrate is finished to the required parallelism, flatness, and surface roughness, and an N1-P alloy layer is formed on its surface by electroless plating to make it a nonmagnetic substrate.The surface of this N1-P alloy layer is polished. Therefore, the surface roughness was calculated by subtracting the cutting depth at 1% relative load length from the cutting depth at 10% relative load length in the relative load curve, ΔC, (10% - 1%), which was 80 ± 6 people. The non-magnetic substrate is precisely cleaned, then dried at room temperature using centrifugal force using the method described above, and a Cr underlayer, a Co alloy magnetic layer, a
-C Protective lubricant layers are sequentially formed and laminated to form a medium. At that time, the cleaning liquid immediately before drying was changed to pure water, an alkaline detergent, and IPA to prepare Examples 1.2 and 303 types of media, respectively. For these media, the surface roughness is ΔC,
(10%-1%) was measured. The results are shown in Table 1.

Table 1 For comparison, a medium was produced in the same manner as in the example except that the same non-magnetic substrate as in the example was used and the drying after precision cleaning was performed using conventional steam immersion cleaning and drying. At that time, Comparative Example 1 and 202 types of media were produced by changing the steam used for drying to IPA and Freon-113, respectively. Table 2 shows the results of measuring the surface roughness ΔCv (10%-1%) for the media of these comparative examples in the same manner as in the examples.

Table 2 From Tables 1 and 2, the surface roughness of the media of the examples is slightly larger than that of the non-magnetic substrate that is the base (
ΔC, (10%-1%) is about 20 people), and the variation is small. On the other hand, the surface roughness of the comparative example medium is significantly larger than that of the non-magnetic substrate (Δ
C, (10%-1%), there are about 150 people, and the variation is very large. It is clear that the method of the example is extremely effective as a method for controlling the surface roughness of the medium. By adopting this normal temperature drying method that utilizes centrifugal force, the surface roughness of the medium can be precisely controlled by the surface roughness of the base non-magnetic substrate, allowing the non-magnetic substrate to have an appropriate surface roughness. By processing it in advance, it becomes possible to obtain a medium having appropriate magnetic head sliding characteristics.

In the above example, the non-magnetic substrate itself was rotated by itself and dried at room temperature using centrifugal force, but the invention is not limited to this. For example, multiple non-magnetic substrates may be set in a holder. By rotating this holder, it is also possible to dry a large number of nonmagnetic substrates at once.

〔Effect of the invention〕

According to the present invention, in a method for manufacturing a thin film magnetic recording medium, drying after precision cleaning of a non-magnetic substrate before sputtering film formation is performed by rotating the non-magnetic substrate and using the centrifugal force generated at room temperature drying. do. By using this drying method, fine, uniform surface microprotrusions are stably formed by sputtering film formation, and variations in the surface roughness of the medium due to variations in surface microprotrusions can be suppressed. .

Therefore, the surface roughness of the medium can be precisely controlled by the surface roughness of the non-magnetic substrate, and by processing the non-magnetic substrate to an appropriate surface roughness, the variation in surface roughness is small and the magnetic It becomes possible to stably mass-produce a thin-film magnetic recording medium having a surface having appropriate magnetic head sliding characteristics that enable the head to run at a stable and extremely low flying height.

The manufacturing method according to the present invention will become more effective as the flying motion of the magnetic head is further reduced in order to obtain a high recording density.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of an embodiment of the drying method of the present invention. ■ Spindle, 2 non-magnetic substrate, 3 nozzle. (a) (b) Figure 1

Claims (1)

[Claims] 1) After cleaning and drying a non-magnetic substrate processed to the required surface roughness, a thin film magnetic layer is formed by sequentially depositing a non-magnetic metal base layer, a magnetic layer, and a protective lubricant layer on this non-magnetic substrate using a sputtering method. 1. A method for manufacturing a thin film magnetic recording medium, characterized in that the drying is carried out at room temperature by rotating a non-magnetic substrate and utilizing centrifugal force at that time.