JP2000117204A - Disk substrate washer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve washing effect by providing with a rotating mechanism for supporting a disk substrate in a straight state to rotate it and a pair of scrub rolls each abutted on both surfaces of the substrate and rotated and feeding washing water to the surface of the disk substrate by the rotation of blades through scrub materials. SOLUTION: At the time of washing a disk substrate 2, a central opening 3 of the substrate 2 is fitted on a substrate holding utensil 4 to make the substrate 2 in a straight state and rotated, and also scrub rolls 6a, 6b are abutted on the surfaces of the substrate 2 and rotated. In this state, washing water is fed from a washing water feeding pipe 9 and is injected into a hollow part of a rotating shaft 7. The injected washing water is forcibly fed downward by blades rotated with the rotating shaft 7 and fed onto the surface of the substrate 2 through scrub materials 5. When feed balance of the washing water is lost and the quantity fed from the washing water feeding pipe is larger than that fed downward by the blades, the balance is discharged from an overflow hole to prevent an overflow from the upper part.

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 technologies such as computers, magnetic recording media such as magnetic disks, and optical recording media such as magneto-optical disks, phase-change optical disks, and DVD-ROMs have been used as external storage devices. 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 treated with Cr or Cr alloy,
An underlayer of an i-Al alloy or the like is formed, and then a magnetic layer of a Co-based alloy is formed, coated with a carbonaceous protective layer, and coated with a lubricant. 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, a very high degree of cleaning is required. Conventionally, cleaning of a disk substrate is performed using a cleaning apparatus shown in FIG. FIG.
In the cleaning apparatus 1, the disk substrate 2 is supported and rotated in an upright state with a substrate holder 4 fitted in an opening 3 provided in the center thereof.

A pair of scrub rolls 6a, 6b having a porous scrub material 5 on the peripheral surface are provided on both surfaces of the disk substrate 2.
Are arranged in contact with each other, and both scrub rolls 6a, 6
b is configured so that a hollow rotary shaft 7 is continuously connected and driven to rotate by a gear 8, and the cleaning water supplied through the cleaning water supply pipe 9 is passed through the hollow rotary shaft 7 into scrub rolls 6a and 6b. And is supplied to the surface of the disk substrate 2 through the scrub material 5.

In the conventional cleaning apparatus 1, as shown in FIG. 4, a cleaning water supply pipe 9 is opened in a hollow rotary shaft 7, and a sliding member is provided between the rotary shaft 7 and the cleaning water supply pipe 9. By sealing the inside of the scrub roll 6 with the interposition of 10, the water pressure in the scrub roll 6 is increased, and the cleaning water is supplied to the surface of the disk substrate 2 through the scrub material 5. For this reason, in the conventional cleaning device 1,
The sliding member 10 fixed to the rotating shaft 7 and rotating slides with the cleaning water supply pipe 9 to generate friction, so that the sliding member 10 is abraded into fine powder and mixed into the cleaning water to mix with the surface of the disk substrate 2. To cause foreign matter to adhere to the surface of the disk substrate 2.

[0008]

SUMMARY OF THE INVENTION The present invention provides a disk substrate cleaning apparatus which is capable of stably supplying cleaning water at a predetermined flow rate without introducing foreign matter into the cleaning water and has an excellent cleaning effect. Is what you do.

[0009]

Means for Solving the Problems The present invention has been made as a result of intensive studies in order to solve such problems.
A rotating mechanism that supports and rotates the disk substrate in an upright state, a cleaning water supply mechanism that supplies cleaning water, and a water-permeable scrubbing material on a peripheral surface, a rotating shaft in a vertical direction, and abutting on both surfaces of the substrate. A hollow rotating shaft is connected to the upper end of the scrub roll, and the blades are fixed inside the scrub roll.The washing water supplied to the rotating shaft is passed through the scrubbing material by the rotation of the blades. An object of the present invention is to provide an apparatus for cleaning a disk substrate, which is supplied to a substrate surface.

[0010]

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. Polishing is performed, for example, by sandwiching a substrate between polishing pads that have been impregnated with free abrasive grains adhered to the surface, and polishing is performed while replenishing a polishing solution such as an aqueous solution of a surfactant. The surface is mirror-finished to 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 fluorine-based 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 the ternary alloy, up to about 10 atomic% of In, Ga, Zn, Sn, Si,
Cu, Au, Ag, Pd, Pt, Pb, Cr, Co,
An alloy thin film containing at least one of O, S, Se, Ta, Nb, and V is exemplified. Alternatively, as a material that can be overwritten at high speed, MSbTe (M = I) mainly containing an SbTe alloy near the eutectic point of Sb ₇₀ Te _30.
n, Ga, Zn, Ge, Sn, Si, Cu, Au, A
g, Pd, Pt, Pb, Cr, Co, O, S, Se, T
a, Nb, V).

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. As metal oxides, Al ₂ O ₃ , Ta ₂ O ₅ , SiO ₂ ,
Metal oxides such as SiO 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
TaS 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,
An oxide film of Al ₂ O ₃ or ZrO or the like;
Usually, it is formed by a sputtering method or the like. More preferred are 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, a dialkylamide carboxylic acid, a perchloropolyether, stearic acid, sodium stearate, a 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 the production of such an information recording medium,
The present invention is applied to cleaning after cleaning or polishing, polishing, grinding, polishing, and texturing the substrate surface. The external structure of the cleaning device 1 of the present invention may be the same as that of the conventional device. As shown in FIG. 1, the substrate holder 4 is fitted into the central opening 3 of the disk substrate 2, and the disk substrate 1 stands upright. Drive state (not shown)
It has a rotation mechanism that rotates. A pair of scrub rolls 6a and 6b having a porous scrub material 5 on the peripheral surface are provided on both surfaces of the disk substrate 2.

As the scrub material 5, a water-permeable and elastic material is used, and an open-cell resin such as urethane foam,
A woven or non-woven fabric of synthetic fibers such as polypropylene and nylon can be used. The scrub roll 6 has a rotating shaft 7
Are arranged in the vertical direction, and are mounted so that the scrubbing material 5 comes into contact with the disk substrate 2. As shown in FIG. 2, the scrub roll 6 has a hollow central portion of the scrub material 5 so that cleaning water can be supplied.

In FIG. 2, the scrub roll 6 has two scrub members 5 formed continuously in the axial direction so that the upper and lower portions of the substrate 2 can be cleaned at the same time. It may be. A hollow rotating shaft 7 is connected to the upper end of the scrub roll 6, and the upper end is connected to a driving source for rotation (not shown) via a gear 8. Of the washing water supply pipe 9 is inserted and opened.

In the cleaning apparatus 1 of the present invention, it is preferable that a slight gap be provided between the hollow rotary shaft 7 and the cleaning liquid supply pipe 9 so that sliding does not occur. Further, a blade 11 is provided inside the rotating shaft 7. The structure of the blade 11 is not particularly limited, and has a function of sending down washing water injected into the hollow portion 12 of the rotating shaft 7 by rotation of the blade 11, and is generally inclined as shown in FIG. Slats 13, 1
3 is used in which a plurality of sheets 3 are radially coupled from the center of rotation. The outer peripheral edges of the blades 13, 13 are fixed to the rotating shaft 7 via an annular body 14. In addition, an overflow mechanism is desirably provided in the upper part of the blade 11 in order to prevent overflow of the washing water when the excessive washing water is injected, and an overflow hole 15 communicating from the hollow part 12 to the outside. , 15 are provided.

Disk substrate 2 using cleaning apparatus 1 of the present invention
When cleaning the disk substrate 2, the central opening 3 of the disk substrate 2 is fitted into the substrate holder 4, the substrate 2 is rotated upright, and scrub rolls 6a,
The scrub rolls 6a and 6b are rotated by contacting the scrub rolls 6b.
Cleaning water is supplied from the cleaning water supply pipe 9 and injected into the hollow portion 12 of the rotating shaft 7. The injected water is pumped downward by a blade 11 fixed to the rotating shaft 7 and rotating with the rotating shaft 7, and the washing water is supplied to the surface of the disk substrate 2 through the scrubbing material 5.

Further, the supply balance of the washing water is lost and the blade 1
When the amount supplied from the washing water supply pipe 9 becomes larger than the amount sent downward by the
5 and can be prevented from overflowing from above. It is desirable that the cleaning water discharged from the overflow pipe 15 be provided with an appropriate cleaning water receiver so as not to flow down onto the disk substrate 2.

[0034]

According to the present invention, the sliding portion between the cleaning water supply pipe and the hollow rotary shaft is eliminated, so that fine powder does not adhere to the disk substrate due to wear of the sliding material. Since the blades are provided, the washing water can be pressed into the scrub roll, and the washing water can be stably supplied to the disk substrate surface at a predetermined flow rate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cleaning device.

FIG. 2 is a partially cutaway side view showing the internal structure of the cleaning device of the present invention.

FIG. 3 is a perspective view showing an example of a blade used in the apparatus of the present invention.

FIG. 4 is a partially cutaway side view showing the internal structure of a conventional cleaning device.

[Explanation of symbols]

 1. Cleaning device 2. Disk board 3. Central aperture 4. Substrate holder 5. 6. Scrub material 6a, 6b Scrub roll Rotation axis 8. Gear 9. Cleaning water supply pipe 11. Feather 12. Hollow 13. Slats 14. Ring

Claims (2)

[Claims] 1. A rotating mechanism for supporting and rotating a disk substrate in an upright state, a cleaning water supply mechanism for supplying cleaning water, and a substrate having a water-permeable scrubbing material on its peripheral surface and a rotating shaft in a vertical direction. It consists of a pair of scrub rolls that contact and rotate on both sides, and a hollow rotary shaft is connected to the upper end of the scrub roll, and the blades are fixed inside the scrub rolls.The cleaning water supplied into the rotary shaft is rotated by the blades. A disk substrate cleaning apparatus configured to feed a disk substrate surface through a scrubbing material. 2. An apparatus for cleaning a disk substrate according to claim 1, wherein an overflow mechanism for discharging excess cleaning water is provided above the blade provided on the hollow rotary shaft.