JPH11232642A - Manufacturing method of magnetic disk - Google Patents

Abstract

(57) Abstract: A method of manufacturing a magnetic disk capable of efficiently removing minute foreign matter generated in a manufacturing process from a substrate surface. In a method of manufacturing a magnetic recording medium having a step of cleaning the surface of a disk, a method of manufacturing a magnetic disk, wherein cleaning by a roll scrub is performed after tape cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of a magnetic disk, and more particularly to a method of manufacturing a magnetic disk with a good yield by efficiently removing abrasive powder generated during tape cleaning after film formation, and residues and deposits after tape cleaning. On how to do it.

[0002]

2. Description of the Related Art In the manufacture of magnetic disks, foreign substances and dust are very reluctant. Therefore, the manufacturing process usually includes a cleaning step of cleaning the surface and removing abnormal projections. Specifically, a cleaning process for removing abrasive grains and shavings after the texturing process, a cleaning process for removing the electrolytic solution after the electrolysis, and a cleaning process for removing fine protrusions performed after the formation of the carbonaceous protective film. And the like. As a cleaning method, a method of showering with ultrapure water, immersion cleaning, a method of bringing a tape carrying (or not carrying) abrasive particles into contact with a rotating disk surface, and the like are widely used.

[0003]

In such a cleaning process, foreign matter and projections flow together with the cleaning liquid.
It is removed from the disk surface by being entangled with the tape, being skipped by the rotation of the disk, and the like. However, as the recording density of the magnetic disk has been increased, the size of foreign matter to be removed (to be removed) has also become extremely small, and has come to adhere smoothly without leaving the disk surface. This phenomenon is particularly remarkable during tape cleaning performed while rotating the disk, particularly during cleaning of the surface of the carbonaceous protective film.

According to the analysis of the present inventor, what remained on the surface of the carbonaceous protective film was very small (submicron or less) abrasive powder, a material for a cleaning tape, and a small film-forming powder adhered during sputtering. there were. The minute foreign matter causes a defect in the magnetic disk, which is a problem during the glide and certification tests.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that it is particularly difficult to remove minute foreign matter by immersion only in a liquid, and that static electricity on the surface is a cause of foreign matter adhesion. And arrived at the present invention. That is,
A first gist of the present invention resides in a method of manufacturing a magnetic recording medium having a step of cleaning the surface of a disk, wherein the cleaning is performed by a roll scrub after the tape cleaning. According to a second aspect of the present invention, there is provided a method of manufacturing a magnetic recording medium including a step of cleaning a disk surface.
The present invention is directed to a method for cleaning a magnetic disk, which comprises removing electricity from the disk during cleaning. Further, the third aspect of the present invention
The gist of the present invention resides in a method for manufacturing a magnetic recording medium having a step of cleaning the surface of a disk, wherein the cleaning is performed by a roll scrub, and the disk is destaticized at the time of cleaning.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as a substrate,
A substrate that is commercially available, called a substrate,
A base film-forming substrate in which a base film of Ni-P electroless plating is provided on the surface of an Al-Mg alloy substrate, and the base film is mirror-finished (polished) is preferably used. In addition, a substrate made of a material such as copper, titanium, glass, ceramic, carbon, and silicon can be used. Usually, the substrate is processed into a disk shape, the thickness of the substrate itself is about 1 to 3 mm, and the thickness of the underlayer is about 20 mm.
３０30 μm.

[0007] Such a substrate is subjected to a texturing process or the like according to a conventional method, and then used. The texture processing is a mechanical processing performed to provide an extremely minute stripe pattern (groove) or unevenness on the mirror surface of the base film. If necessary, chemical etching or electrolytic etching (electropolishing) can be performed as a finishing process for removing burrs and burrs after the texturing process. By these processes, the attraction between the magnetic disk and the magnetic head is prevented, the contact start / stop (CSS) characteristics are improved, and the magnetic anisotropy is improved.

The underlayer formed on the substrate may be a conventionally known nonmagnetic underlayer, and may be formed of, for example, Cr, Ti, Ni, or the like. The Cr or Ti of the underlayer may be an alloy containing Si, V, Cu, etc. in a range that does not impair the crystallinity thereof, for example, in a range of several atomic%. In the present invention, a Cr-based underlayer is particularly preferable. The thickness of the underlayer is usually 50 to 200.
0 ° range.

The magnetic layer formed on the underlayer of the substrate is generally made of Co-Cr, Co-Ni, Co-Cr-.
It is a cobalt-based alloy thin film layer represented by X, Co-Ni-X, Co-WX or the like. Here, X is Li, S
i, P, Ca, Ti, V, Cr, Ni, As, Y, Z
r, Nb, Mo, Ru, Rh, Ag, Sb, Hf, T
a, W, Re, Os, Ir, Pt, Au, La, Ce,
One or more elements selected from the group consisting of Pr, Nd, Pm, Sm, Eu and B are used.

The magnetic layer is usually formed on the underlayer of the substrate by means such as sputtering. The thickness of the magnetic layer is usually preferably in the range of 100 to 1000 °. The protective layer includes a carbon film, a hydrogenated carbon film, a nitrogenated carbon film, a carbonized film such as TiC and SiC, a nitride film such as SiN and TiN, and an oxide film such as SiO, Al ₂ O ₃ and ZrO. Usually, it is formed by a sputtering method or the like. As the protective layer, a carbon film, a hydrogenated carbon film and a nitrogenated carbon film are particularly preferable.

The hydrogenated carbon film is not particularly limited as long as it is a film containing hydrogen and carbon. For example, a sputter gas (usually using an inert gas such as argon) using a carbon target is used. ) And sputtering in a plasma containing hydrogen gas. The content of hydrogen in the sputtering atmosphere is usually 2 to 20% by volume.

The nitrogenated carbon film is not particularly limited as long as it contains nitrogen and carbon. For example, a sputter gas, a nitrogen gas, a nitrogen monoxide gas, a nitrogen dioxide gas, It can be formed by sputtering in a plasma containing a nitrogen-containing gas such as ammonia gas or a nitrogen-containing gas such as air. For example, when air is used, the content of air in the sputtering atmosphere is usually 2 to 20% by volume.
It is.

Further, for example, by simultaneously mixing a hydrogen gas and a nitrogen (containing) gas into a sputtering gas,
A hydrogenated and nitrogenated carbon film can also be formed. The thickness of the protective layer is usually in the range of about 50-1000 °, preferably about 100-600 °. After the tape cleaning step after the formation of the protective layer, a lubricant layer is usually provided on the surface of the protective layer. As a lubricant, for example,
A fluorine-based liquid lubricant is used, and is usually formed on the surface of the protective layer by a dip coating method, a spin coating method, a spray coating method, or the like. The thickness of the lubricant layer is usually about 5
It is in the range of Å50 °.

As the polishing tape, there is usually used a polishing tape in which a film made of polyethylene terephthalate, polyamide, or the like carries polishing grains such as alumina particles and SiC particles having a particle size of 0.3 to 3 μm. For example, "AWA8000 FN" manufactured by Nihon Micro Coating Co., Ltd.
Y "," AWA8000 NA1-C "or the like can be used.

The cleaning according to the present invention can be applied between any steps of the above-mentioned magnetic disk manufacturing process. However, since the cleaning from the formation of the underlayer to the formation of the carbonaceous protective layer is usually performed sequentially by sputtering. It is preferable to perform before the formation of the underlayer or after the formation of the carbonaceous protective layer and before the application of the lubricant. The greatest effect can be obtained when applied after forming the carbonaceous protective film and before applying the lubricant.

In the present invention, the cleaning is preferably performed by a roll scrub. The material of the scrub roll is not particularly limited, but a sponge-based material such as polyvinyl alcohol and polyurethane, which does not easily generate waste, is preferably used.

Further, when performing the cleaning, the effect of the cleaning can be further enhanced by performing a static elimination treatment. In the static elimination process, cleaning is performed while grounding the substrate using a conductive spindle, and a member such as a static elimination brush or a static elimination roller (FIG. 1A) composed of a conductive member is brought into contact with the disk. Washing, use of a cleaning solution having a small electric resistance, and the like can be mentioned. When a plurality of these are used in combination, the static elimination effect is increased.

Although it is preferable that the electric resistance of the cleaning liquid is low, the liquid itself may adversely affect the magnetic disk.
Pure water having a small electric resistance is preferred. A specific electric resistance value is preferably 10Ω to 1MΩ. Such pure water can be obtained by supplying pure water and carbon dioxide to a mixing nozzle, as shown in FIG. Such a cleaning liquid is effective not only in cleaning by roll scrub but also in other cleaning methods in that the efficiency of removing foreign substances is increased.

FIG. 2 is a front view of an essential part showing an example of the cleaning apparatus. The outer periphery of the disk 1 is supported by a plurality of disk transport rollers and static elimination rollers 2. The roll scrub 3 has its shaft connected to the motor 6 and is supported so as to come into contact with the surface of the disk 1 at a predetermined pressure. Further, a nozzle 5 is arranged at a position where the cleaning liquid can be supplied to the surface of the disk 1 and the roll scrub 3.

In this state, the roll scrub 3 is rotated while supplying the cleaning liquid from the nozzle 5, and
By moving the disk 1 and cleaning the surface of the disk 1, foreign substances on the surface can be effectively removed.

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. (Example) After forming a Cr underlayer, a Co alloy magnetic layer and a hydrogenated carbonaceous protective layer on a Ni-P plated aluminum alloy substrate by sputtering, fine protrusions and foreign substances on the surface of the carbonaceous protective film are removed by tape cleaning. after,
Scrub cleaning was performed using the apparatus of FIG. At this time, a neutralizing roller is used as the transport roller 2 and CO 2
Washing water (pure water) that was made conductive (20,000 Ω) by blowing _two gases was used.

A glide test was performed on the 10 discs after cleaning at a glide height of 0.6 μm, and the surface was observed with an optical microscope to count the number of foreign substances having a size of 0.2 μm or more. The amount of Co remaining on the surface, which is considered to be the cause of the aggregation of the agent, was measured, and the average value is shown in Table 1.

(Comparative Example) The same procedure as in the example was performed up to tape cleaning, and the same measurement as in the example was performed without performing scrub cleaning. Table 1 shows the results.

[0024]

[Table 1]

[0025]

As described above, according to the present invention,
This makes it possible to efficiently remove minute foreign matter adhering to the disk surface, to achieve stable production of the magnetic disk, and to reduce the possibility of lubricant corrosion. In the embodiments, the present invention is applied after the tape cleaning of the carbonaceous protective film. However, the present invention can be applied to any place in the manufacturing process of the magnetic disk.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a static elimination roller and a mixing nozzle applicable to the present invention.

FIG. 2 is a diagram showing an example of a cleaning device suitable for implementing the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc 2 Transport roller (static elimination roller) 3 Roll scrub 5 Nozzle 6 Motor

Claims (7)

[Claims] 1. A method for manufacturing a magnetic recording medium comprising a step of cleaning the surface of a disk, the method comprising: cleaning the tape with a roll scrub after cleaning the tape. 2. A method for manufacturing a magnetic recording medium, comprising the step of cleaning the surface of a disk, the method comprising: removing static electricity from the disk during cleaning. 3. A method for manufacturing a magnetic recording medium, comprising the step of cleaning the surface of a disk, wherein the cleaning is performed by a roll scrub, and the disk is neutralized during cleaning. 4. The method of manufacturing a magnetic disk according to claim 1, wherein the disk is neutralized by supporting the disk with a grounded conductive member. 5. A magnetic liquid according to claim 1, wherein the cleaning liquid is a liquid having a lower resistance than pure water and having substantially no influence even if it remains on the magnetic disk surface. Disc manufacturing method. 6. The method according to claim 5, wherein the cleaning liquid is carbonated water. 7. A method for manufacturing a magnetic disk having a carbonaceous protective film on a magnetic layer, the method comprising:
4. A method for manufacturing a magnetic disk, comprising applying the cleaning according to claim 1 before applying a lubricant.