JP2000149251A - Cleaning device for disk substrate and cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the rotation of a substrate and to enable cleaning to be performed in a high speed rotation by providing three or more driving rollers supporting and rotating a disk substrate when cleaning is performed supporting and rotating a disk substrate. SOLUTION: The outer periphery part of a disk substrate 1 is supported by movable driving rollers 2, 3, and a fixed driving roller 4 between them, and supported in the vertical state. Rotary power is given to the disk substrate 1 by these three driving rollers and the disk 1 is rotated, and cleaning is performed with a scrubbing roll and the like. These three driving rollers 2, 3, 4 are rotated at constant speed through one driving shaft from a drive source and three belts 8, 9, 10 or a gear. The disk 1 is rotated by three rollers at the time of cleaning, at the time of loading a disk and unloading a disk after finish of cleaning, two movable driving rollers 2, 3 at the upper part are moved to the upper side by moving roller moving members 6, 7 to the upper side, and supporting the disk substrate 1 is released without moving the roller 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk substrate cleaning apparatus, and more particularly to a disk substrate cleaning method suitable for cleaning a substrate in the manufacture of an information recording medium such as a magnetic disk and an optical recording disk.

[0002]

2. Description of the Related Art In recent years, with the development of information processing technology such as computers, magnetic recording devices and optical recording devices as external storage devices, magnetic recording media such as magnetic disks, magneto-optical disks and phase change Type optical disc, DV
Optical recording media such as D-ROMs are widely used. Conventionally, as a magnetic recording medium, a non-magnetic substrate obtained by subjecting an aluminum alloy substrate to a non-magnetic plating treatment such as an alumite treatment or Ni-P plating is coated with Cr or a Cr alloy, Ni-Al.
An underlayer of an alloy or the like is formed, and then a magnetic layer of a Co-based alloy is formed, covered with a carbonaceous protective layer, and a lubricant is applied. In such a magnetic recording medium, the recording density has been increasing, and the distance between the magnetic disk and the magnetic head, that is, the flying height has been reduced, and recently, 0.10 μm or less is required.

As an optical recording medium, a magneto-optical disk in which a reflective layer, a magnetic layer, and a protective layer are formed on a plastic substrate and then coated with a lubricant is used, but the flying height of the magneto-optical disk is 3 μm or less. Floating head or contact head. When the flying height of the recording or reproducing head is small, high uniformity of the recording medium surface is required, and if there is a foreign substance, a head crash may occur, leading to breakage.・ It may cause a playback error.

In addition, a magnetic disk or the like causes an adhesion phenomenon that the head is fixed to the disk surface and does not fly when the disk is started, or the head and the disk come into contact during operation and normal rotation is hindered due to frictional resistance. There are problems. In particular, the size of the magnetic disk is also being reduced in parallel with the above-mentioned high density (low flying height), and the motor for rotating the spindle is becoming smaller. As a result, the torque of the motor is insufficient, and there is a possibility that an adhesion phenomenon in which the magnetic head does not float while being fixed to the magnetic disk surface at the time of startup may occur. In addition, the magnetic head may come into contact with the magnetic disk during operation, and normal rotation may be hindered due to frictional resistance.

As means for preventing the occurrence of these phenomena, in the case of a magnetic disk, surface treatment called texture processing for forming fine irregularities on the substrate surface is performed. After such texturing or polishing, very sophisticated cleaning is required to remove burrs or dust. FIG. 2 is a schematic view of a disk support rotating unit of a conventional disk substrate cleaning apparatus. The disk substrate 1 has its ends supported by three rollers: a driving roller 12, a driving roller 13, and a support roller 14 having no driving unit. The disk substrate 1 is rotated by being given a rotational force by the driving rollers 12 and 13, and is cleaned by a scrub roll (not shown) or the like. After the cleaning is completed, the drive roller 12 moves upward in the figure, the drive roller 13 and the support roller 14 move downward in the figure, and releases the support of the disk substrate 1.

[0006]

By the way, in recent years, there has been an increasing demand for an improvement in cleaning power and a reduction in cleaning time, and the number of revolutions of a disk substrate during cleaning has rapidly increased.
~ 300 rpm, but recently 1000 rpm
Is reaching. However, in the conventional cleaning apparatus, when the disk substrate is rotated at a high speed, the support roller 14 slips, which causes uneven rotation of the disk substrate, and a part of the disk substrate is not sufficiently cleaned. There was such a problem. The present invention has been made in view of the above problems, and stabilizes the rotation of a substrate during disk substrate cleaning.
It is another object of the present invention to enable cleaning at a high rotation speed and to improve the cleaning power and reduce the cleaning time.

[0007]

Means for Solving the Problems The present invention has been made as a result of intensive studies in order to solve such problems.
The gist of the present invention resides in an apparatus for cleaning a disk substrate that supports and rotates the disk substrate and performs cleaning while rotating the disk substrate, the apparatus including three or more drive rollers that support and rotate the disk substrate. . Also,
Another aspect of the present invention is a method of cleaning a disk substrate that supports and rotates a disk substrate and performs cleaning while rotating the disk substrate while supporting and rotating the disk substrate with three or more drive rollers. The present invention resides in a method of cleaning a disk substrate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to cleaning of a disk substrate for an information recording medium such as a magnetic recording medium, a magneto-optical disk, a phase change optical disk, and an optical recording medium such as a DVD-ROM. Cleaning of the disc substrate for the information recording medium is performed after polishing, texturing, polishing, etc. of the disc substrate. In the present invention, the disk substrate includes those at each stage from a device forming a base of a recording medium to a product in which functional layers are laminated to a product.

As a magnetic recording medium, an underlayer, a magnetic layer and a protective layer are generally formed on a substrate in this order. As the non-magnetic substrate of the magnetic recording medium used in the present invention, an aluminum-based metal generally made of aluminum or an aluminum alloy is used, and after processing this into a disk-shaped substrate having a predetermined thickness, the surface is mirror-finished. Processed. A non-magnetic metal such as a Ni-P alloy or N
After laminating an i-Cu-P alloy or the like by electroless plating or the like, and further performing a texturing process, an underlayer, a magnetic layer, a protective layer, and the like are laminated to form a magnetic disk.

As a substrate processing step before the texturing step, a strip-shaped aluminum-based thin metal plate is cut into a substrate shape, and then a chamfering step of grinding a corner portion is performed, and a grinding step of smooth grinding is performed. Ni-P
And the like, and a polishing step for smoothing the surface are performed. During that time, a firing (heat treatment) step for removing the stress distortion generated in the previous step is performed.

In the polishing process, for example, a substrate is sandwiched between polishing pads having free abrasive grains adhered to the surface and impregnated, and polishing is performed while replenishing a polishing solution such as an aqueous solution of a surfactant. After polishing, the surface is mirror-finished to have an average surface roughness Ra of 50 Å or less, preferably 30 Å or less.

As the texture processing, for example, 2
By means of tape grinding using a polishing tape carrying alumina abrasive grains of about 500 to 6000 #, or slurry grinding using loose abrasive grains, the polished substrate surface has an average surface roughness Ra of 20 Å or more, preferably Is formed with a precision of 30 to 300 angstroms, more preferably 50 to 150 angstroms, in which the crossing angle of the streaks is preferably 10 to 40 °, more preferably 10 to 30 °. It is preferable to form a cross-pattern streak on the substrate surface in that the adsorption characteristics are improved.

An underlayer is formed on the textured substrate. 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. In addition, Cr or Ti of the underlayer may be an alloy containing Si, V, Cu, or the like 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 angstrom 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 base layer of the substrate by means such as sputtering. The thickness of the magnetic layer is usually preferably in the range of 100 to 1000 Å.

The protective layer includes a carbon film, a hydrogenated carbon film, a nitrogenated carbon film, a carbonized film such as TiC and SiC, SiN,
It is composed of a nitride film such as TiN, an oxide film such as SiO, Al ₂ O ₃ , ZrO and the like, and is usually formed by a sputtering method. As the protective layer, a carbon film, a hydrogenated carbon film, and a nitrogenated carbon film are particularly preferable. After the protective layer is formed, polishing is performed, and after cleaning, a lubricant is applied. Preferably, the thickness of the lubricating layer ranges from about 15 to 50 Angstroms. Further, a heat treatment may be performed after the formation of the lubricating layer. The heating temperature is 50 ° C. or higher, but may be appropriately selected at a temperature lower than the decomposition temperature of the lubricant.

As the lubricant, a fluorinated liquid lubricant is preferable. Particularly, a compound having a hydroxyl group at a terminal or a side chain and having a fluorocarbon skeleton in a molecular skeleton, for example,
Perfluorocarboxylic acid ester, perfluorothiolcarboxylic acid ester, perfluorodicarboxylic acid ester, perfluorocarboxylic acid perfluoroalkyl ester, perfluorobenzoic acid ester, carboxylic acid perfluoroalkyl ester, dicarboxylic acid perfluoroalkyl ester, carboxylic acid Perfluoroalkoxyalkyl ester, perfluorocarboxylic acid amide,
Perfluoropolyether, perfluoropolyether carboxylic acid, perfluoropolyether alcohol, perfluoropolyether ester, and the like can be used.

On the other hand, a resin substrate provided with pits and grooves is used for an optical recording medium. Examples of the resin include an acrylic resin, a norbornene resin, a polyolefin resin, a liquid crystal polymer, and a polycarbonate. Examples of the resin include polymethyl methacrylate (PMMA) and ARTON.
(Nippon Synthetic Rubber Co., Ltd. Norbornene-based ester-substituted cyclic olefin ring-opening polymer hydrogenated product), ZEONEX (Nippon Zeon Co., Ltd., norbornene-based cyclic olefin ring-opening polymer hydrogenated product), aromatic polyester-based liquid crystal polymer, polycarbonate and the like. .

Based on a stamper provided with pits and grooves, pits / grooves are transferred and formed by injection molding, injection compression molding, radiation curing or the like using these resins to form a resin substrate. Unlike glass, metal, ceramic, and the like, by using a resin, fine pits or grooves having a width or length of 2 μm or less and a depth of 100 nm or less can be formed accurately and at low cost. Substrate thickness is 0.4-2m
m is common. If the thickness is too thin, the substrate is bent by its own weight and it is difficult to obtain flatness, but if it exceeds 2 mm, there is no great difference in strength.

As the optical recording layer formed on the substrate, various types can be used, for example, a magneto-optical recording layer, a phase change recording layer, and a dye recording layer. The layer configuration is not particularly limited, and various layer configurations can be adopted. As the magneto-optical recording layer, for example, TbFe, Tb
bFeCo, TbCo, GdFeCo, DyTbFeC
an amorphous magnetic layer of a rare earth such as o and a transition metal, MnBi,
A polycrystalline perpendicular magnetization layer such as MnCuBi, a Pt / Co multilayer film or the like is used. The magneto-optical recording layer may be a single layer, or GdT to enable overwriting and MSR.
Two or more magnetic layers such as bFe / TbFe may be stacked and used.

As the phase change type recording layer, for example, GeSb
Te, InSbTe, AgSbTe, AgInSbTe
Can be used. Preferably, ｛(Sb _{2
Te 3) 1-x (GeTe} ) x} 1-y Sb y (0.2 <x <
0.9, 0 ≦ y <0.1) alloy, and 1 for the ternary alloy
In, Ga, Zn, Sn, Si, C up to about 0 atomic%
u, Au, Ag, Pd, Pt, Pb, Cr, Co, O,
An alloy thin film containing at least one of S, Se, Ta, Nb, and V is exemplified. Alternatively, as a material that can be overwritten at a high speed, Sb ₇₀ Te ₃₀ near the eutectic point
MSbTe (M = In, G
a, Zn, Ge, Sn, Si, Cu, Au, Ag, P
d, Pt, Pb, Cr, Co, O, S, Se, Ta, N
(At least one of b and V) alloy thin film is preferable.

On the optical recording layer, a transparent intermediate layer having properties such as weather resistance, high hardness and high lubricity is provided. The material of the intermediate layer is selected in consideration of these properties. As the intermediate layer, a dielectric is preferable, and metal oxides, nitrides, chalcogenides, carbides, fluorides, and mixtures thereof are used. Al ₂ O ₃ , Ta ₂ O ₅ , SiO ₂ , Si
Metal oxides such as O and TiO ₂ alone or a mixture thereof, or a composite oxide of Al—Ta—O may be used. Examples of the metal nitride include silicon nitride and aluminum nitride.

As chalcogenides, ZnS, ZnS
II-V such as chalcogenide zinc such as e, CdS and CdSe
Group compounds, rare earth sulfides such as La ₂ S ₃ and Ce ₂ S ₃ , Ta
S ₂ , MgS, CaS and the like can be mentioned. Zinc chalcogenide is chemically stable, and among them, ZnS is particularly preferable because of its low toxicity. Examples of a method for forming these dielectric layers include vapor deposition and sputtering, and sputtering is more preferred. Materials with excellent lubricity include carbon film, hydrogenated carbon film, nitrogenated carbon film, TiC, S
carbide film such as iC, nitride film such as SiN and TiN, SiO,
It is composed of an oxide film such as Al ₂ O ₃ or ZrO, and is usually formed by a sputtering method or the like. More preferably,
A carbon film, a hydrogenated carbon film, and a nitrogenated carbon film.

The intermediate layer has a role as a protective layer and a lubricating layer, but may have a plurality of layers. For example, when a protective layer having high weather resistance and high hardness is provided on the side in contact with the recording layer, and a lubricating layer having excellent lubricity is provided on the side in contact with the lubricating layer, both excellent properties can be obtained as a whole, which is preferable. . As the layer in contact with the magneto-optical recording layer, silicon nitride, Si
O ₂ and Ta ₂ O ₅ are preferably used. As a layer in contact with the phase-change recording layer, a mixture of ZnS and a metal oxide is preferably used.

Preferably, a reflective layer is provided between the substrate and the recording layer. As the reflective layer, a metal or an alloy having a high reflectance is used, for example, Al, Ag, Au, Cu, or an alloy containing these as a main component. Further, a substrate or a reflective layer,
A transparent intermediate layer may be provided between the recording layer and the recording layer for the purpose of interfering and amplifying light or protecting the recording layer. As the material, the above-described dielectric or the like is preferably used. A lubricant layer can be formed on the outermost layer of these optical recording media.

The lubricant may be the same as that used for the magnetic disk, but is preferably a perfluoropolyether having an ester bond, dialkylamidocarboxylic acid, perchloropolyether, stearic acid, sodium stearate, phosphate ester, or the like. . The ester bond may be located anywhere in the molecule, but it is more preferable to have an ester bond functional group at the end, since the movable portion in the molecule becomes longer and lubricity is easily obtained. Particularly -C _a F _2a O- units (wherein, a is an integer of 1 to 4) in the main chain has a perfluoropolyether having a functional group of the terminal ester bond.

The molecular weight of the lubricant is preferably in the range of 100 to 10,000. If the molecular weight is low, the vapor pressure is generally high, and it evaporates little by little after coating, and deviates from a desired film thickness with time. Conversely, when the molecular weight is high, the viscosity is generally high, and the desired lubricity may not be obtained.
As a solvent for dissolving these, for example, a fluorocarbon type, alcohol type, hydrocarbon type, ketone type, ether type, fluorine type, aromatic type, etc. are used. The coating thickness of the lubricant is preferably in the range of 1 to 20 nm. If the thickness is out of this range, that is, if the thickness is too small, the desired lubricity cannot be obtained. The film thickness distribution in the periphery is likely to occur.

In manufacturing such an information recording medium,
The present invention is applied to scrub roll cleaning, jet cleaning, and the like after performing processing such as cleaning, polishing, grinding, polishing, and texture processing of a substrate surface. Hereinafter, a disk substrate cleaning apparatus and a cleaning method of the present invention will be described with reference to FIG. FIG. 1 is a schematic view of a disk support rotating unit of a disk substrate cleaning apparatus according to the present invention.

The external structure of the cleaning apparatus of the present invention may be the same as that of the conventional apparatus. As shown in FIG. 1, the outer peripheral edge of the disk substrate 1 is moved by the movable drive roller 2, the movable drive roller 3, and the fixed drive roller 4. And the disk substrate 1 is held upright. The disk substrate 1 is rotated by being given a rotational force by the three driving rollers, and is cleaned by a scrub roll (not shown) or the like.

These three drive rollers 2, 3, 4
For example, it is configured to rotate at a constant speed from a drive source (not shown) through one drive shaft 5 and three belts 8, 9, 10 or gears. At the time of washing, the roller is rotated by three rollers. At the time of receiving the disc and at the time of discharging after the end of washing, the two movable rollers 2 and 3 at the top of the figure are moved by moving the roller moving members 6 and 7 upward in the figure. It moves upward and releases the support of the disk substrate 1 without moving the roller 4.

The lower roller is always fixed. Of course, one fixed roller may be arranged at the upper part, and two movable rollers may be arranged at the lower part. Since the disk substrate is rotated by three or more drive rollers, slip which causes disk rotation unevenness is very unlikely to occur. In particular, the effect is large when cleaning is performed at a high speed of 500 rpm or more, at which slipping easily occurs.

As a result, it is possible to suppress the occurrence of defective cleaning of the substrate due to uneven rotation of the disk substrate. Preferably, at least one of the rollers is a fixed drive roller. Further, it is preferable that these rollers are arranged on both sides of the disk, not before and after the disk with respect to the flow of the disk. In other words, when cleaning is performed while rotating and supporting the disk substrate in an upright state, the disk substrate is disposed above and below the disk.

With this arrangement, the rollers do not obstruct the flow of the disk, and only the two movable rollers need to be removed from the side of the disk in a series of steps of disk receiving, rotating cleaning, and disk discharging, so that the moving line is cut. There is no. Therefore, the disk substrate can be cleaned with a simple line, and the entire cleaning equipment can be made compact.

The number of drive rollers is at least three, and a support roller and a drive roller may be additionally provided. The scrub roll for cleaning the disc substrate has a porous scrub material on the peripheral surface, for example, a water-permeable and elastic material is used as the scrub material, open-cell resin such as urethane foam, polypropylene A woven or non-woven fabric of synthetic fibers such as nylon and the like can be used.

[0034]

According to the present invention, it is possible to stabilize the rotation of the substrate at the time of cleaning the disk substrate, to perform cleaning at a high speed, to improve the cleaning power and to reduce the cleaning time.

[Brief description of the drawings]

FIG. 1 is a schematic view of a rotating unit for supporting a disk of a cleaning apparatus according to the present invention.

FIG. 2 is a schematic view of a disk supporting rotary unit of a conventional cleaning device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc substrate 2, 3 Movable drive roller 4 Fixed drive roller 5 Roller drive shaft 6, 7 Roller moving member 8, 9, 10 Belt 12, 13 Drive roller 14 Support roller

Claims (3)

[Claims] An apparatus for cleaning a disk substrate that supports and rotates the disk substrate while cleaning the disk substrate, the apparatus comprising three or more drive rollers for supporting and rotating the disk substrate. . 2. The method according to claim 1, wherein the at least three drive rollers include at least one fixed roller and at least one movable roller.
The cleaning device according to item 1. 3. A method for cleaning a disk substrate, wherein the disk substrate is cleaned while being supported and rotated, wherein the disk substrate is supported by three or more drive rollers and cleaned while being rotated. Cleaning method.