WO2010047119A1 - Apparatus for cleaning substrate for magnetic recording medium, and method for cleaning substrate for magnetic recording medium - Google Patents

Abstract

Provided are an apparatus and a method for cleaning a substrate for a magnetic recording medium, wherein a cleaning solution does not easily scatter to surrounding areas, and a substrate which is for a magnetic recording medium and applicable to low floating of a magnetic head above a magnetic recording surface and has high cleanliness is obtained.  The apparatus for cleaning a substrate (1) for a magnetic recording medium is provided with: a cleaning solution nozzle (4) which supplies the cleaning solution onto the substrate (1); a cleaning tool (3) composed of a porous material; a sliding means which slides the cleaning tool (3) on the substrate (1); and a cleaning solution discharging means (7) which sucks and discharges the cleaning solution from over the substrate (1) through the cooling tool (3).

Description

Magnetic recording medium substrate cleaning apparatus and magnetic recording medium substrate cleaning method

The present invention relates to a magnetic recording medium substrate cleaning apparatus and a magnetic recording medium substrate cleaning method, and more particularly, to a magnetic recording medium substrate cleaning apparatus and magnetic recording medium from which a magnetic recording medium substrate having high cleanliness can be obtained. The present invention relates to a method for cleaning an industrial substrate.
This application claims priority based on Japanese Patent Application No. 2008-273098 filed in Japan on October 23, 2008, the contents of which are incorporated herein by reference.

Generally, an aluminum substrate or a glass substrate is used as a substrate for a magnetic recording medium used in a hard disk drive or the like. In recent years, the recording density of magnetic recording media has been increasing, and high flatness is required for the surface of the magnetic recording medium substrate so as to cope with the low flying height of the head on the magnetic recording surface. High cleanliness is required.
For this reason, there is a demand for an advanced cleaning technique for removing dust and the like adhering to the surface of the magnetic recording medium substrate.

As a method for cleaning a magnetic recording medium substrate, for example, in Patent Document 1, a surface treatment such as polishing is performed on the surface of a workpiece such as a magnetic disk substrate, and then foreign matter adhering to the surface of the workpiece is removed. In order to remove the workpiece, the workpiece is washed with a liquid while being conveyed by a conveyor in the washing tank, and then the workpiece washed with the liquid is taken out from the washing tank one by one, and the workpiece is removed by a rotating brush of a scrubbing machine. A method of scrub cleaning one by one is disclosed. Examples of the scrub cleaner used here include those having a cup-type or roll-type rotating brush that contacts the surface of a workpiece.

Further, Patent Document 2 describes that the polishing surface to be washed away by scrub cleaning, loose abrasive grains of polish, etc. are sucked into the pad made of sponge-like resin and stayed in the pad to prevent the substrate surface from being scratched. In order to achieve this, a technique has been disclosed in which a gap portion communicating with each other is provided in the internal structure of the sponge pad, and cleaning water is supplied from the bottom surface of the pad to the surface.

JP 2001-96245 A JP 2000-315318 A

However, the increase in the recording capacity of the magnetic recording medium is becoming more intense, and a higher cleanliness than ever is required for the method of cleaning the magnetic recording medium substrate. For this reason, the extremely fine deposits that have been allowed until now have been regarded as a problem as a cause of defects.
For example, when the technique described in Patent Document 2 is adopted, dust and the like in the pad flows out from the pad by the cleaning water, so that the pad can be kept clean. Polishing free abrasive grains may adhere to the cleaning substrate.
Further, the conventional cleaning apparatus has a disadvantage that the cleaning liquid for the magnetic recording medium substrate is scattered around.

The present invention has been made in view of the above problems, and provides a magnetic recording medium substrate having a high cleanliness that can prevent the cleaning liquid from scattering to the surroundings and can cope with a low flying height of the magnetic head on the magnetic recording surface. An object of the present invention is to provide a cleaning device for a magnetic recording medium substrate.
Also provided are a method for cleaning a substrate for a magnetic recording medium in which the cleaning liquid is less likely to scatter around and a high cleaning finish is obtained, and a method for manufacturing a magnetic recording medium that can cope with a low flying height of the head on the magnetic recording surface. With the goal.

The inventors of the present invention made extensive efforts to solve the above problems. As a result, when cleaning is performed by sliding the cleaning tool on the magnetic recording medium substrate while supplying the cleaning liquid onto the magnetic recording medium substrate, the cleaning tool is made of a porous material, and at least one of the cleaning liquids is used. The part is sucked and discharged through the cleaning tool, so that the cleaning liquid is not easily scattered around, and dust such as dust released from the magnetic recording medium substrate and the cleaning tool by the cleaning is placed on the magnetic recording medium substrate. It was found that adhesion could be prevented and a high cleaning finish was obtained, and the present invention was completed. That is, the present invention relates to the following.

(1) A cleaning liquid nozzle for supplying a cleaning liquid onto the magnetic recording medium substrate, a cleaning tool made of a porous material, sliding means for sliding the cleaning tool on the magnetic recording medium substrate, and the magnetic recording A cleaning apparatus for a magnetic recording medium substrate, comprising: a cleaning liquid discharger that sucks and discharges the cleaning liquid from the medium substrate through the cleaning tool.

(2) The cleaning tool is cylindrical and is rotated about a direction parallel to the surface with a side surface facing the surface of the magnetic recording medium substrate. A discharge passage for discharging the cleaning liquid sucked from the side surface is formed along a central axis, and the cleaning liquid discharge means is a cleaning liquid discharge pipe attached to an end of the discharge passage, and the cleaning liquid The apparatus for cleaning a substrate for a magnetic recording medium according to (1), further comprising a pressure reducing means for reducing the pressure in the discharge pipe.
(3) The cleaning tool is cylindrical and is rotated with an end surface facing the surface of the magnetic recording medium substrate and a direction orthogonal to the surface as an axis. The substrate for a magnetic recording medium according to (1), comprising: a cleaning liquid discharge pipe attached to the other end surface of the cylindrical shape of the cleaning tool; and a pressure reducing means for reducing the pressure in the cleaning liquid discharge pipe. Cleaning equipment.
(4) The cleaning liquid nozzle, the cleaning tool, the sliding means, and the cleaning liquid discharge means are each provided in two, and are arranged symmetrically with respect to the magnetic recording medium substrate ( The apparatus for cleaning a substrate for a magnetic recording medium according to 2) or (3).

(5) a cleaning step of supplying a cleaning liquid onto the magnetic recording medium substrate by a cleaning liquid nozzle and sliding a cleaning tool made of a porous material on the magnetic recording medium substrate; A method for cleaning a magnetic recording medium substrate, wherein at least a part of the cleaning liquid is sucked and discharged from the magnetic recording medium substrate through the cleaning tool.
(6) In the cleaning step, two cleaning tools arranged so as to sandwich the magnetic recording medium substrate are slid on both surfaces of the magnetic recording medium substrate, respectively. Cleaning method for a magnetic recording medium substrate.

(7) A method of manufacturing a magnetic recording medium, comprising the step of cleaning the magnetic recording medium substrate using the magnetic recording medium substrate cleaning device according to any one of (1) to (4). .

The apparatus for cleaning a magnetic recording medium substrate of the present invention includes cleaning liquid discharge means for sucking and discharging the cleaning liquid from the magnetic recording medium substrate through a cleaning tool. By sucking and discharging the cleaning liquid through the cleaning tool, it becomes difficult for the cleaning liquid to scatter to the surroundings, and dust such as dust discharged from the magnetic recording medium substrate by cleaning is discharged from the magnetic recording medium substrate. After that, it can be quickly sucked together with the cleaning liquid and captured by the cleaning tool. Therefore, when cleaning is performed using the magnetic recording medium substrate cleaning apparatus of the present invention, the dust released from the magnetic recording medium substrate by cleaning does not come into contact with the magnetic recording medium substrate again, and the magnetic recording is performed by cleaning. The dust released from the recording medium substrate can be quickly removed from the magnetic recording medium substrate.
In addition, the magnetic recording medium substrate cleaning apparatus of the present invention includes cleaning liquid discharge means for sucking and discharging the cleaning liquid from the magnetic recording medium substrate through the cleaning tool. The dust released from the magnetic recording medium substrate captured by the cleaning tool is not released again.

As described above, when cleaning is performed using the magnetic recording medium substrate cleaning apparatus of the present invention, dust released from the magnetic recording medium substrate by cleaning does not come into contact with the magnetic recording medium substrate again, and the cleaning tool. As a result, no waste is discharged into the cleaning liquid, so that a high cleaning finish can be obtained. As a result, it is possible to realize a magnetic recording medium substrate having a high cleanliness that can cope with a low flying height of the magnetic head on the magnetic recording surface.

In the method for cleaning a magnetic recording medium substrate according to the present invention, in the cleaning step, at least a part of the cleaning liquid is sucked and discharged from the magnetic recording medium substrate through the cleaning tool. Therefore, it is possible to prevent dust released from the magnetic recording medium substrate by cleaning and dust released from the cleaning tool from adhering to the magnetic recording medium substrate, and a high cleaning finish can be obtained.
Further, according to the method for manufacturing a magnetic recording medium of the present invention, a surface with high cleanliness can be obtained in the step of cleaning the magnetic recording medium substrate using the magnetic recording medium substrate cleaning apparatus of the present invention. A magnetic recording medium that can cope with a low flying height of the head on the surface can be obtained.

FIG. 1 is a diagram showing an example of a magnetic recording medium substrate cleaning apparatus according to the present invention. FIG. 2 is a plan view of another example of the magnetic recording medium substrate cleaning apparatus of the present invention as viewed from above the magnetic recording medium substrate.

A magnetic recording medium substrate cleaning apparatus, a magnetic recording medium substrate cleaning method, and a magnetic recording medium manufacturing method according to the present invention will be described below with reference to the drawings.
“First Embodiment”
In this embodiment, as an example of a magnetic recording medium substrate cleaning apparatus and a magnetic recording medium substrate cleaning method, a case of performing a magnetic recording medium substrate cleaning step included in a magnetic recording medium manufacturing process will be described. To do. Here, the cleaning process of the magnetic recording medium substrate may be a cleaning process performed at any stage in the manufacturing process of the magnetic recording medium. For example, so as to obtain a predetermined surface average roughness Ra, It can be a scrub cleaning step after mechanical texture processing is performed on the surface of the magnetic recording medium substrate.

FIG. 1A is a plan view of an example of a magnetic recording medium substrate cleaning apparatus according to the present invention as viewed from above the magnetic recording medium substrate. 1B is a cross-sectional view taken along the line AA ′ of the cleaning apparatus shown in FIG. 1A, and FIG. 1C is a cross-sectional view taken along the line BB ′ of the cleaning apparatus shown in FIG. FIG. Moreover, FIG.1 (d) is the expansion perspective view which expanded and showed the brush with which the washing | cleaning apparatus shown to Fig.1 (a) was equipped.

The cleaning apparatus shown in FIGS. 1 (a) to 1 (d) uses a cleaning liquid nozzle 4 for supplying a cleaning liquid onto a magnetic recording medium substrate 1 to be cleaned, a brush (cleaning tool) 3, and a brush 3 for magnetic recording. A sliding means for sliding on the medium substrate 1 and a cleaning liquid discharging means 7 for sucking and discharging the cleaning liquid from the magnetic recording medium substrate 1 through the brush 3 are provided. Further, two each of the cleaning liquid nozzle 4, the brush 3, the sliding means and the cleaning liquid discharge means 7 are provided and are arranged symmetrically with respect to the magnetic recording medium substrate 1. 1 may be arranged so that the magnetic recording medium substrate 1 is horizontal, or may be arranged so that the magnetic recording medium substrate 1 is vertical, The magnetic recording medium substrate 1 may be disposed so as to be inclined.

The magnetic recording medium substrate 1 is an object to be cleaned before performing a cleaning process included in the manufacturing process of the magnetic recording medium. Examples of the magnetic recording medium substrate 1 include a general disk-shaped substrate having a diameter of about 3.5 inches or less and having an opening at the center. The material of the magnetic recording medium substrate 1 is not particularly limited, but an Al alloy substrate, a glass substrate, a ceramic substrate, a flexible resin substrate, and a NiP film on which a NiP plating film is formed are deposited by sputtering. Examples include substrates.

Further, the cleaning liquid nozzle 4 supplies a cleaning liquid such as water and a surfactant to the magnetic recording medium substrate 1 in a predetermined supply amount.

Further, in this embodiment, two brushes 3 are provided, and as shown in FIGS. 1A and 1B, the two brushes 3 sandwich the magnetic recording medium substrate 1. Is arranged. The brush 3 is made of a porous material such as a sponge-like resin having a large number of voids, and a PVA (polyvinyl alcohol) sponge or the like is used. The PVA sponge is made of PVA, which is a hydrophilic polymer, has high water absorption and water retention, and has characteristics suitable for cleaning applications. Furthermore, it is preferable to use a PVA sponge stored in a storage solution containing hydrogen peroxide as the brush 3. The brush 3 taken out from the storage liquid is preferably used after washing out the storage liquid contained in the brush 3 by a method of washing in pure water.

In the present embodiment, a brush (roll type) is used as the brush 3, and the side surface 3 a is arranged to face the surface of the magnetic recording medium substrate 1.
Moreover, as shown in FIG.1 (d), each brush 3 is formed with the discharge channel | path 3b along the cylindrical central axis. The discharge passage 3 b is for discharging the cleaning liquid sucked from the side surface 3 a of the brush 3.

The sliding means slides the brush 3 on the magnetic recording medium substrate 1. The chuck roller 2 that holds and rotates the magnetic recording medium substrate 1 and the rotating means that rotates the brush 3 ( (Not shown).
In this embodiment, the chuck roller 2 is used in common for the sliding means used for cleaning one surface side of the magnetic recording medium substrate 1 and the sliding means used for cleaning the other surface side. . As shown in FIG. 1A, four chuck rollers 2 are arranged at regular intervals in contact with the outer periphery of the magnetic recording medium substrate 1. Then, by rotating the four chuck rollers 2 in the same direction at a predetermined number of rotations, the magnetic recording medium substrate 1 is held by the chuck rollers 2 and orthogonal to the surface of the magnetic recording medium substrate 1. The axis is rotated at a predetermined speed with the direction to be used as an axis.
In the present embodiment, as shown in FIGS. 1B and 1C, the two brushes 3 are respectively in a state where the side surfaces 3a face the surface of the magnetic recording medium substrate 1, respectively. The rotating means (not shown) is rotated at a predetermined rotational speed in opposite directions with the direction parallel to the surface of the magnetic recording medium substrate 1 as an axis.

In the present embodiment, the cleaning liquid discharge means 7 includes a cleaning liquid discharge pipe 7a attached to the end of the discharge passage 3b provided in the brush 3, and a pressure reducing means such as a pump for reducing the pressure in the cleaning liquid discharge pipe 7a. (Not shown). Therefore, in this embodiment, the pressure in the cleaning liquid discharge pipe 7a is reduced by the pressure reducing means so that at least a part of the cleaning liquid on the magnetic recording medium substrate 1 is formed on the side surface 3a of the brush 3 made of a porous material. It is sucked from a certain sliding surface, passes through a gap in the brush 3, and is discharged to the outside through the discharge passage 3b and the cleaning liquid discharge pipe 7a in order.
Specifically, the pressure in the cleaning liquid discharge pipe 7a is about the vicinity of the brush 3 when the pressure in the cleaning liquid discharge pipe 7a is sucked with a vacuum pump (decompression means) having an ultimate pressure of about 0.01 Pa and the atmospheric pressure is set to 101325 Pa. It is preferable to adjust so that the cleaning liquid is appropriately sucked when the pressure in the cleaning liquid discharge pipe 7a is 100000 Pa or less.

In order to clean the magnetic recording medium substrate 1 using the cleaning apparatus shown in FIGS. 1A to 1D, first, the magnetic recording medium substrate 1 to be cleaned is held by the chuck roller 2 and magnetic recording is performed. Two brushes 3 are arranged so as to sandwich the medium substrate 1 from both sides. Then, the cleaning liquid is supplied onto the magnetic recording medium substrate 1 by the cleaning liquid nozzle 4, and the chuck roller 2 is rotated in the direction of the arrow shown in FIG. In addition, the brush 3 is rotated in the direction of the arrow shown in FIGS. 1B and 1C by rotating in the direction of the arrow shown in FIG. The brush 3 is slid to clean both surfaces of the magnetic recording medium substrate 1 simultaneously (cleaning process). In the present embodiment, in the cleaning process, the pressure in the cleaning liquid discharge pipe 7a is reduced by the pressure reducing means, and at least a part of the cleaning liquid is sucked from the magnetic recording medium substrate 1 through the brush 3 to the discharge passage 3b. And discharged to the outside through the cleaning liquid discharge pipe 7a.

In the present invention, it is preferable that the entire amount of the cleaning liquid used in the cleaning process is discharged to the outside through the brush 3, but if at least a part of the cleaning liquid is sucked and discharged through the brush 3. The effect of the present invention can be obtained without discharging the entire amount of the cleaning liquid to the outside.

The cleaning device for the magnetic recording medium substrate 1 according to the present embodiment includes the cleaning liquid discharging means 7 that sucks and discharges the cleaning liquid from the magnetic recording medium substrate 1 through the brush 3. By sucking and discharging the cleaning liquid, dust such as dust discharged from the magnetic recording medium substrate 1 by cleaning is quickly sucked together with the cleaning liquid after being discharged from the magnetic recording medium substrate 1 and is captured by the brush 3. be able to. Therefore, in the cleaning method of this embodiment, the dust released from the magnetic recording medium substrate 1 by the cleaning does not come into contact with the magnetic recording medium substrate 1 again, and is quickly removed from the magnetic recording medium substrate 1. Is done. Further, in the cleaning method of the present embodiment, since the cleaning liquid is sucked and discharged from the magnetic recording medium substrate 1 through the brush 3, even if dust such as dust adheres to the brush 3, the brush 3 Dust is not released into the cleaning liquid, and dust released from the magnetic recording medium substrate 1 captured by the brush 3 is not released again.

Here, for example, in a conventional cleaning device that supplies a cleaning liquid from the outside using a nozzle or supplies a cleaning liquid from the inside of a sponge-like scrub pad, a clean cleaning liquid is always supplied to a portion to which the cleaning liquid is supplied. However, the cleaning liquid containing dust such as dust discharged from the magnetic recording medium substrate or the cleaning tool by the cleaning may come into contact with the object to be cleaned, and the dust may adhere to the object to be cleaned.
On the other hand, in the cleaning method of this embodiment, dust released from the magnetic recording medium substrate 1 by cleaning does not come into contact with the magnetic recording medium substrate 1 again, and dust such as dust is collected from the brush 3 into the cleaning liquid. Since it is not released, a high cleaning finish is obtained. Therefore, according to the present embodiment, it is possible to obtain the magnetic recording medium substrate 1 having a high cleanliness that can cope with the low flying height of the magnetic head on the magnetic recording surface.

In the cleaning apparatus for the magnetic recording medium substrate 1 of the present embodiment, the cleaning liquid is sucked and discharged from the magnetic recording medium substrate 1 through the brush 3. It becomes difficult for the cleaning liquid supplied to.

In the cleaning apparatus for the magnetic recording medium substrate 1 according to the present embodiment, the brush 3 is cylindrical and rotates with the side surface 3a facing the surface of the magnetic recording medium substrate 1 and a direction parallel to the surface as an axis. A discharge passage 3b for discharging the cleaning liquid sucked from the side surface 3a is formed along the cylindrical central axis of the brush 3, and the cleaning liquid discharge means 7 is connected to the end of the discharge passage 3b. In the cleaning process, the pressure in the cleaning liquid discharge pipe 7a is reduced by the pressure reducing means in the cleaning step. At least a part of the cleaning liquid on the magnetic recording medium substrate 1 is sucked from the sliding surface which is the side surface 3a of the brush 3 made of a porous material and passes through the gap in the brush 3, and the discharge passage 3b and the cleaning liquid discharge pipe The fuel to be discharged to the outside through the a sequentially.

Therefore, in the cleaning device of the present embodiment, dust such as dust is removed from the magnetic recording medium substrate 1 by rubbing the sliding surface, which is the side surface 3a of the brush 3, and the magnetic recording medium substrate 1 in the presence of the cleaning liquid. When released, the dust immediately after being released from the magnetic recording medium substrate 1 can be captured by the brush 3 together with the cleaning liquid from the sliding surface which is the side surface 3 a of the brush 3. In the cleaning device of the present embodiment, the discharge passage 3b for discharging the cleaning liquid sucked from the side surface 3a is formed along the cylindrical central axis of the brush 3. The unevenness of the suction force of the cleaning liquid is reduced, the dust discharged from the magnetic recording medium substrate 1 can be efficiently removed, and the cleaning liquid is efficiently discharged to the outside through the discharge passage 3b and the cleaning liquid discharge pipe 7a. It becomes.

In the cleaning apparatus for the magnetic recording medium substrate 1 of the present embodiment, two cleaning liquid nozzles 4, brushes 3, sliding means and cleaning liquid discharge means 7 are provided, two each, with respect to the magnetic recording medium substrate 1. Since the two brushes 3 are slid on both surfaces of the magnetic recording medium substrate 1 in the cleaning process, the entire surfaces of both surfaces of the magnetic recording medium substrate 1 can be simultaneously cleaned. A cleaning process can be performed efficiently.

Further, in the cleaning apparatus for the magnetic recording medium substrate 1 of the present embodiment, when a PVA sponge stored in a storage solution containing hydrogen peroxide is used as the brush 3, the mold on the PVA sponge being stored is moldy. It is possible to sufficiently prevent inconvenience caused by the occurrence of. Therefore, when the magnetic recording medium substrate 1 is washed using the brush 3 stored in a storage solution containing hydrogen peroxide, mold does not adhere to the surface of the magnetic recording medium substrate 1, and during storage. Even if the hydrogen peroxide used is contained in the brush 3, it is discharged to the outside through the discharge passage 3b and the cleaning liquid discharge pipe 7a together with the cleaning liquid at the time of cleaning, so that the surface of the cleaned magnetic recording medium substrate 1 is removed. Hydrogen peroxide does not remain. Furthermore, when using the brush 3 stored in a storage solution containing hydrogen peroxide, it is not necessary to use a conventional antifungal agent. Therefore, the conventional antifungal agent is used for the magnetic recording medium substrate 1 after cleaning. It does not remain on the surface. Therefore, a higher cleaning finish can be obtained.

In the above-described embodiment, in order to slide the brush 3 on the magnetic recording medium substrate 1, the chuck roller 2 is rotated to rotate the magnetic recording medium substrate 1, and the brush 3 is rotated by rotating means. However, the method is not limited to the method in which both the magnetic recording medium substrate 1 and the brush 3 are simultaneously rotated, and only one of them may be rotated.

In the above-described embodiment, the case where the discharge passage 3b for discharging the cleaning liquid sucked from the side surface 3a is formed along the cylindrical central axis of the brush 3 has been described as an example. The shape of the discharge passage 3b is not limited to the shape of the present embodiment. For example, branch passages extending radially from the discharge passage toward the side surface 3a may be connected to the discharge passage extending along the central axis of the cylinder so that the cleaning liquid can be discharged efficiently and uniformly. And it is good also as what was provided in the spiral form so that the cylindrical central axis might be enclosed.

“Second Embodiment”
FIG. 2 is a plan view of another example of the magnetic recording medium substrate cleaning apparatus of the present invention as viewed from above the magnetic recording medium substrate. In the cleaning apparatus shown in FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The cleaning apparatus shown in FIG. 2 magnetically operates a cleaning liquid nozzle 4 for supplying a cleaning liquid onto the magnetic recording medium substrate 1 to be cleaned, a brush (cleaning tool) 5 and the brush 5 in the same manner as the cleaning apparatus shown in FIG. A sliding means for sliding on the recording medium substrate 1 and a cleaning liquid discharging means 71 for sucking and discharging the cleaning liquid from the magnetic recording medium substrate 1 through the brush 5 are provided. Also, in the cleaning apparatus shown in FIG. 2, the cleaning liquid nozzle 4, the brush 5, the sliding means, and the cleaning liquid discharge means 71 are provided two by two and are arranged symmetrically with respect to the magnetic recording medium substrate 1. (In FIG. 2, only one surface side of the magnetic recording medium substrate is shown, and the cleaning liquid nozzle 4, the brush 5, the sliding means and the cleaning liquid discharging means 71 installed on the other surface side are not shown). In the cleaning apparatus shown in FIG. 2, the magnetic recording medium substrate 1 may be arranged so as to be horizontal, or the magnetic recording medium substrate 1 may be arranged so as to be vertical. The magnetic recording medium substrate 1 may be disposed so as to be inclined.

Also in the present embodiment, two brushes 5 are provided, and the two brushes 5 are arranged so as to sandwich the magnetic recording medium substrate 1. Also in this embodiment, the brush 5 is made of a porous material such as sponge-like resin having a large number of voids, and PVA sponge or the like is used. Furthermore, it is preferable to use a PVA sponge stored in a storage solution containing hydrogen peroxide as the brush 5. The brush 5 taken out from the storage liquid is preferably used after washing out the storage liquid contained in the brush 5 by a method of washing in pure water.
The brush 5 is cylindrical (cup type), and is arranged with one end face facing the surface of the magnetic recording medium substrate 1. As shown in FIG. 2, an arm 6 for holding the brush 5 is attached to the other end surface 5 a of the brush 5.

The sliding means slides the brush 5 on the magnetic recording medium substrate 1 and holds four chucks similar to the cleaning apparatus shown in FIG. 1 that holds and rotates the magnetic recording medium substrate 1. It comprises a roller 2 and a rotating means (not shown) for moving and rotating the brush 5 to a predetermined position via the arm 6. In the present embodiment, as shown in FIG. 2, the magnetic recording medium substrate 1 is rotated by a rotating means (not shown) with each brush 5 facing one end face of the surface of the magnetic recording medium substrate 1. The direction perpendicular to the surface of the magnetic recording medium is rotated at a predetermined rotational speed in the same direction, and the relative position with respect to the magnetic recording medium substrate 1 is moved.

In the present embodiment, the cleaning liquid discharge means 7 is attached to the other end surface 5a of the brush 5, and the cleaning liquid discharge pipe 71a partially embedded in the arm 6 and the pressure in the cleaning liquid discharge pipe 71a are reduced. Pressure reducing means (not shown) such as a pump. Therefore, in this embodiment, the pressure in the cleaning liquid discharge pipe 71a is reduced by the pressure reducing means so that at least a part of the cleaning liquid on the magnetic recording medium substrate 1 is at one end surface of the brush 5 made of a porous material. It is sucked from a certain sliding surface, passes through the gap in the brush 5, and is discharged to the outside through the cleaning liquid discharge pipe 71a.

In order to clean the magnetic recording medium substrate 1 using the cleaning apparatus shown in FIG. 2, first, the magnetic recording medium substrate 1 to be cleaned is held by the chuck roller 2, and the magnetic recording medium substrate 1 is sandwiched from both sides. Two brushes 5 are disposed on the surface. Then, the cleaning liquid is supplied onto the magnetic recording medium substrate 1 by the cleaning liquid nozzle 4, the chuck roller 2 is rotated to rotate the magnetic recording medium substrate 1 in the direction of arrow B shown in FIG. 2 is rotated in the direction of arrow A shown in FIG. 2, and the brushes 5 are slid on both surfaces of the magnetic recording medium substrate 1 to clean both surfaces of the magnetic recording medium substrate 1 simultaneously (cleaning step). In the present embodiment, in the cleaning process, the pressure in the cleaning liquid discharge pipe 71a is reduced by the pressure reducing means, and at least a part of the cleaning liquid is sucked from the magnetic recording medium substrate 1 through the brush 5 to be the cleaning liquid discharge pipe. It discharges outside through 71a.

The cleaning apparatus for the magnetic recording medium substrate 1 according to the present embodiment includes the cleaning liquid discharge means 71 that sucks and discharges the cleaning liquid from the magnetic recording medium substrate 1 via the brush 5, so that the first embodiment is described. In the same manner as described above, the cleaning liquid is less likely to be scattered around, and the dust released from the magnetic recording medium substrate 1 by the cleaning does not come into contact with the magnetic recording medium substrate 1 again. Since no dust is discharged, a high cleaning finish is obtained, and the magnetic recording medium substrate 1 having a high cleanliness that can cope with a low flying height of the magnetic head on the magnetic recording surface is obtained.

Further, in the cleaning apparatus for the magnetic recording medium substrate 1 of the present embodiment, the brush 5 is cylindrical and rotates with the one end surface facing the surface of the magnetic recording medium substrate 1 and the direction orthogonal to the surface as an axis. Since the cleaning liquid discharge means 71 includes the cleaning liquid discharge pipe 71a attached to the cylindrical other end face 5a of the brush 5, and the pressure reducing means for reducing the pressure in the cleaning liquid discharge pipe 71a, In the cleaning step, the pressure in the cleaning liquid discharge pipe 71a is reduced by the pressure reducing means, whereby at least a part of the cleaning liquid on the magnetic recording medium substrate 1 is a sliding surface that is one end face of the brush 5 made of a porous material. Is sucked from the air, passes through the gap in the brush 5, and is discharged to the outside through the cleaning liquid discharge pipe 71a.

Therefore, in the cleaning apparatus of this embodiment, dust such as dust is removed from the magnetic recording medium substrate 1 by rubbing the sliding surface which is one end surface of the brush 5 and the magnetic recording medium substrate 1 in the presence of the cleaning liquid. When released, the dust immediately after being released from the magnetic recording medium substrate 1 can be captured by the brush 5 together with the cleaning liquid from one end surface of the brush 5 which is a sliding surface. Further, in the cleaning device of the present embodiment, the cleaning liquid discharge means 71 includes the cleaning liquid discharge pipe 71a attached to the cylindrical other end face 5a of the brush 5, and therefore, at one end face of the brush 5 which is a sliding surface. The unevenness of the suction force of the cleaning liquid is small, dust discharged from the magnetic recording medium substrate 1 can be efficiently removed, and the cleaning liquid is efficiently discharged to the outside through the cleaning liquid discharge pipe 71a.

Also in the cleaning apparatus for the magnetic recording medium substrate 1 of the present embodiment, two cleaning liquid nozzles 4, brushes 5, sliding means and two cleaning liquid discharge means 71 are provided, respectively, with respect to the magnetic recording medium substrate 1. Since the two brushes 5 are respectively slid on both surfaces of the magnetic recording medium substrate 1 in the cleaning process, the entire surfaces of both surfaces of the magnetic recording medium substrate 1 can be simultaneously cleaned. The cleaning process can be performed efficiently.

“Third Embodiment”
Next, a method for manufacturing a magnetic recording medium including the step of cleaning the magnetic recording medium substrate using the magnetic recording medium substrate cleaning apparatus of the first embodiment or the second embodiment will be described.
First, a magnetic recording medium substrate 1 made of a predetermined material is prepared, and the surface of the magnetic recording medium substrate 1 is polished so that the surface of the magnetic recording medium substrate 1 has a predetermined average surface roughness Ra. Subsequently, the magnetic recording medium substrate 1 is immersed and washed in a cleaning tank containing a detergent. Next, the magnetic recording medium substrate 1 is scrubbed by the above-described cleaning method using the magnetic recording medium substrate cleaning apparatus of the first embodiment or the second embodiment.

Thereafter, on the cleaned surface of the magnetic recording medium substrate 1, using a sputtering method, for example, a base film made of a nonmagnetic alloy such as a CrW alloy and a magnetic recording layer film made of a magnetic alloy such as a CoCrPtTaCu alloy are formed. Form. Thereafter, a protective film made of a hard carbon film is formed on the magnetic recording layer film by using, for example, a plasma CVD method, and a PFPE lubricant is formed on the surface of the magnetic recording medium substrate 1 on which the protective film is formed by a dipping method. Is applied to form a magnetic recording medium.

According to the method for manufacturing a magnetic recording medium of this embodiment, the cleanliness level is obtained by performing the step of cleaning the magnetic recording medium substrate using the magnetic recording medium substrate cleaning apparatus of the first embodiment or the second embodiment. Therefore, a magnetic recording medium that can cope with a low flying height of the head on the magnetic recording surface can be obtained.

"Example"
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
(Example)
As a magnetic recording medium substrate, a disk-shaped aluminum alloy substrate having a diameter of 3.5 inches and a thickness of 0.8 mm, on which a NiP plating film having a thickness of 10 μm was formed, was prepared. The surface of the magnetic recording medium substrate was subjected to mechanical texture processing so that the surface average roughness Ra was 1 nm. Subsequently, the magnetic recording medium substrate was immersed and washed in a cleaning tank containing an alkaline detergent (trade name: RBS225, manufactured by Chemical Product Co., Ltd.) having a concentration of 5%.

Thereafter, the both surfaces of the magnetic recording medium substrate were simultaneously scrubbed three times using the cleaning apparatus shown in FIG. In this scrub cleaning, the brush 5 was stored in a storage solution composed of 5% by mass of hydrogen peroxide solution at 30 ° C. for 7 days, and the storage solution was washed away from the brush by a method of washing in pure water with a diameter of 8.5 cm. A 2 cm thick cup-type PVA sponge (manufactured by Eagle Chemical Co., Ltd.) was used. The scrub cleaning conditions are as follows: the rotation speed of the brush 5 is 500 rpm, the rotation speed of the magnetic recording medium substrate 1 is 120 rpm, the scrub cleaning time per one is 8 seconds, and the supply amount of pure water is 1 as the cleaning liquid from the cleaning liquid nozzle 4 Feeded at liters / minute. During cleaning, the pressure in the cleaning liquid discharge pipe 71a is reduced to 90000 Pa, and the cleaning liquid used for cleaning is sucked from the magnetic recording medium substrate 1 through the brush 5 and discharged to the outside through the cleaning liquid discharge pipe 71a. However, almost no cleaning liquid was discharged from other than the cleaning liquid discharge pipe 71a, and there was almost no cleaning liquid scattered around.

On the surface of the magnetic recording medium substrate thus cleaned, a base film made of a CrW alloy having a thickness of 8 nm (25 mass% Cr-75 mass% W) and a CoCrPtTaCu Cu having a thickness of 30 nm are formed by sputtering. A magnetic recording layer film made of an alloy (18 mass% Cr-8 mass% Pt-3 mass% Ta-1 mass% Cu-balance Co) was formed. Thereafter, a protective film made of a carbon film having a thickness of 7 nm is formed on the magnetic recording layer film using a plasma CVD method, and a PFPE lubricant is applied to the surface of the magnetic recording medium substrate on which the protective film is formed by a dipping method. A magnetic recording medium was manufactured by a coating method.

(Comparative example)
A cleaning device similar to the cleaning device shown in FIG. 2 is used except that no cleaning liquid discharging means is provided, and the cleaning liquid is not sucked and discharged through a brush during cleaning, as in the embodiment. Thus, a magnetic recording medium was manufactured.

The surface shape of the magnetic recording medium was inspected for 100 sheets of the magnetic recording media of the examples and comparative examples thus obtained using a glide tester in which a head with piezoelectric elements was used. The head glide height (distance between the head and the magnetic recording medium) was 0.25 μinch.
As a result, in the example, no defective portion was found on 100 magnetic recording media. On the other hand, two defects were found in the comparative example. The two defective magnetic recording media of the comparative examples were presumed to be caused by substances remaining on the surface of the magnetic recording medium substrate during scrub cleaning.

Further, the magnetic recording media of Examples and Comparative Examples were observed with a differential interference optical microscope (600 times). As a result, in the magnetic recording medium of the comparative example, blistering due to poor scrub cleaning of the magnetic recording medium substrate occurred in the vicinity of the center of the laminated film composed of the magnetic recording layer film or the like. On the other hand, in the magnetic recording medium of the example, a good magnetic recording layer film was formed.

DESCRIPTION OF SYMBOLS 1 ... Substrate for magnetic recording media, 2 ... Chuck roller, 3 ... Brush, 3a ... Side surface, 3b ... Discharge passage, 4 ... Cleaning liquid nozzle, 5 ... Brush, 6 ... Arm, 7, 71 ... Cleaning liquid discharge means, 7a, 71a ... cleaning fluid discharge pipe.

Claims (8)

1. A cleaning liquid nozzle for supplying a cleaning liquid onto the magnetic recording medium substrate;
   A cleaning tool made of a porous material;
   Sliding means for sliding the cleaning tool on the magnetic recording medium substrate;
   A cleaning apparatus for a magnetic recording medium substrate, comprising: a cleaning liquid discharger that sucks and discharges the cleaning liquid from the magnetic recording medium substrate through the cleaning tool.
2. The cleaning tool is cylindrical and has a side face opposed to the surface of the magnetic recording medium substrate, and is rotated about a direction parallel to the surface. A discharge passage for discharging the cleaning liquid sucked from the side surface is formed along
   2. The magnetic recording according to claim 1, wherein the cleaning liquid discharge means includes a cleaning liquid discharge pipe attached to an end portion of the discharge passage, and a decompression means for reducing the pressure in the cleaning liquid discharge pipe. Cleaning device for medium substrate.
3. The cleaning tool has a cylindrical shape, and one end surface thereof is opposed to the surface of the magnetic recording medium substrate, and is rotated about a direction orthogonal to the surface,
   The said cleaning liquid discharge means is equipped with the cleaning liquid discharge pipe attached to the said cylindrical other end surface of the said cleaning tool, and the pressure reduction means which pressure-reduces the pressure in the said cleaning liquid discharge pipe. An apparatus for cleaning a magnetic recording medium substrate as described.
4. 3. The cleaning liquid nozzle, the cleaning tool, the sliding means, and the cleaning liquid discharge means are each provided in two, and are arranged symmetrically with respect to the magnetic recording medium substrate. An apparatus for cleaning a magnetic recording medium substrate as described.
5. The cleaning liquid nozzle, the cleaning tool, the sliding means, and the cleaning liquid discharge means are each provided in two, and are arranged symmetrically with respect to the magnetic recording medium substrate. An apparatus for cleaning a magnetic recording medium substrate as described.
6. A cleaning step of supplying a cleaning liquid onto the magnetic recording medium substrate by a cleaning liquid nozzle and sliding a cleaning tool made of a porous material on the magnetic recording medium substrate;
   In the cleaning step, at least a part of the cleaning liquid is sucked and discharged from the magnetic recording medium substrate through the cleaning tool.
7. 7. The magnetic recording according to claim 6, wherein in the cleaning step, two cleaning tools arranged so as to sandwich the magnetic recording medium substrate are respectively slid on both surfaces of the magnetic recording medium substrate. A method for cleaning a substrate for a medium.
8. A method for manufacturing a magnetic recording medium, comprising the step of cleaning the magnetic recording medium substrate using the magnetic recording medium substrate cleaning apparatus according to claim 1.

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