JP2006172669A - Method for cleaning master information carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method capable of preventing reverse contamination caused by foreign objects contained in a gas such as air by using the deformation recovery force of a master information carrier itself to perform a separating operation, and maintaining sufficient cleanliness. <P>SOLUTION: In a magnetic transfer master information carrier 7 having a magnetic film formed an arrangement pattern on a substrate surface corresponding to a predetermined information signal, the surface having the magnetic film of the master information carrier 7 formed thereon and a dummy disk 3 are bent into recessed or projected shapes to bring them into surface contact with each other, and thereby transfers the contaminants of the surface of the master information carrier 7 to the dummy disk 3 side to clean the surface of the master information carrier 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic transfer master information carrier cleaning method for recording predetermined tracking servo information on a magnetic disk used in a hard disk drive or the like.

In recent years, in magnetic recording / reproducing apparatuses, not only has the demand for higher recording density increased as the amount of information increases, but also the miniaturization of the apparatus is rapidly progressing. In the field of a hard disk drive (hereinafter referred to as “HDD”), which is a typical magnetic recording / reproducing apparatus, a technology relating to an apparatus having a recording density of 100 Gbit / in ² has been rapidly advanced.

  The technical background that enables such a high recording density is that the signal recorded on a track width of about several μm has an S / N ratio (signal-to-noise ratio) while improving the linear recording density. In addition to increasing the output of a magnetoresistive head that can be reproduced while being sufficiently large, and optimal design of a flying slider that achieves a flying height of about 10 nm with respect to a magnetic disk, the head accurately scans a narrow track. Tracking servo technology also plays an important role.

  Further, the flying slider is desired to further reduce the flying height, but on the other hand, there is an increased risk that the magnetic disk and the flying slider may be brought into contact with each other during operation to destroy data.

  In current HDDs using such tracking servo technology, tracking servo signals, address information signals, reproduction clock signals, etc. are generated at a constant angle and interval during one round (360 ° angle) of the magnetic disk. It is recorded. Then, by detecting the position of the head from these signals reproduced from the head at regular time intervals and correcting the position, the head can accurately scan the track.

  Since the servo signal, address information signal, reproduction clock signal, etc. described above serve as reference signals for the head to accurately scan the track, high positioning is required for writing (hereinafter referred to as “formatting”). Accuracy is required.

  In current HDDs, formatting is performed by positioning a recording head using a dedicated servo device (hereinafter referred to as “servo writer”) incorporating a high-accuracy position detection device using optical interference. However, the following problems exist in formatting by the servo writer.

  First, it takes a lot of time to write signals over many tracks while positioning the head with high accuracy. As a result, productivity for formatting is poor, and in order to increase productivity, many servo writers must be operated simultaneously. Secondly, the introduction and maintenance of many servo writers is expensive. For these, as the track density increases and the number of tracks increases, it becomes a larger problem.

  Therefore, a magnetic transfer method has been proposed instead of a method in which formatting is performed by a servo writer. In this magnetic transfer system, a master information carrier, on which all servo information is written in advance, is superimposed on a magnetic disk to be formatted, and the information on the master information carrier is transferred from outside by applying energy for transfer. This is a method of batch transfer to a magnetic disk.

  However, in this magnetic transfer system, if there are contaminants or the like that affect the servo information on the transfer surface of the master information carrier, the transferred servo information may be defective. For this reason, the surface of the master information carrier is required to maintain a clean surface free from minute contaminants.

As an example of a method for this purpose, a magnetic portion made of a ferromagnetic material having a pattern shape corresponding to an information signal is formed on the surface of the substrate to form a master information carrier for magnetic transfer, and the pattern of the master information carrier for magnetic transfer. A method is disclosed in which contaminants on the surface of the master information carrier are removed by alternately repeating the step of bringing the forming surface and the dummy disk into close contact and the step of separating them alternately a plurality of times (for example, see Patent Document 1).
JP 2003-51113 A

  The master information carrier is a disk for magnetically transferring a magnetization pattern corresponding to an information signal to a magnetic disk, and is required to magnetically transfer a fine magnetization pattern of about submicron. For this reason, contaminants including foreign matter generated on the surface of the master information carrier cause a defect in a servo signal to be magnetically transferred even if it is in a minute shape, causing a transfer failure.

  In addition, contaminants including foreign substances are attached to the surface of the master information carrier by a plurality of generation sources such as a manufacturing process of the master information carrier and an environment for magnetic transfer. Therefore, it is essential to clean the master information carrier before magnetic transfer. However, even in such a cleaning process, contaminants may adhere depending on the environmental conditions.

  However, the above-described conventional method has a problem that contaminants attached to the surface of the master information carrier for magnetic transfer cannot be completely removed. That is, when removing contaminants on the surface of the conventional master information carrier, exhausting the gas existing at the master information carrier and the dummy disk interface and bringing it into close contact, and pumping the gas to the interface described above, By repeating the above, contaminants adhering to the surface of the master information carrier are transferred to the surface of the dummy disk, and are further discharged to the outside by the gas fed under pressure, thereby cleaning the master information carrier.

  In such a process, in particular, when gas is pumped in the case of separating, depending on the cleanliness of the gas, fine foreign substances in the gas may adhere to the master information carrier and contaminate the surface.

  In other words, in the case of close contact, the gas existing at the contact interface between the master information carrier and the dummy disk is exhausted to make close contact. For this reason, if the work environment such as a clean room has a sufficient degree of cleanliness, contaminants that lead to defects do not adhere.

  On the other hand, in the case of separation, gas is pumped away to the interface between the master information carrier and the dummy disk that are in close contact with each other. For this reason, depending on the quality of the gas used, the master information carrier surface may be contaminated. Therefore, it is necessary to improve the quality of the gas to be pumped. However, in the case of air generated by a compressor that is generally used as such a gas, complicated management is required to maintain the quality, such as air piping members and path lengths, or installation and management of filters for dust and mist. is required. In this respect, there are many cases where contaminants mixed in the air cannot be completely removed. It may also result in oil, moisture or dust being sent to the surface of the master information carrier at the same time as separation, which may also contaminate the surface of the master information carrier.

  As a preventive measure, a method using an air dryer or the like at the inlet is also conceivable. However, even in this case, if the piping path to the cleaning device becomes long, the cleaned air may be contaminated by flowing in the piping.

  There is also a method of removing fine contaminants by installing a filter on the apparatus side. In this method, impurities can be temporarily removed, but clogging occurs when impurities are continuously mixed. Furthermore, exceeding the removal limit not only reduces the air flow rate and affects the separation, but also the impurities that could not be removed diffuse to the master information carrier surface, resulting in contamination of the master information carrier surface. Become.

  When magnetic transfer is performed in a state where the master information carrier is contaminated in this way, not only servo signals are lost, but also an arrangement pattern of servo information formed by a magnetic film on the master information carrier may be lost. In such a case, the master information carrier must be discarded, which causes a problem in terms of cost.

  The cleaning method of the master information carrier of the present invention prevents the back contamination by the foreign matter contained in the gas such as air by performing the separation operation using the deformation recovery force of the master information carrier itself. An object of the present invention is to provide a cleaning method capable of maintaining a high degree of cleanliness.

  In order to solve the above-mentioned problems, the master information carrier cleaning method of the present invention relates to a master information carrier for magnetic transfer in which an array pattern corresponding to a predetermined information signal is formed on a substrate surface with a magnetic film. The surface of the master information carrier and the dummy disk are curved in a concave or convex shape and the surface of the master information carrier and the dummy disk are brought into surface contact with each other. It consists of a method of cleaning the surface of the master information carrier by moving to the disk side.

  By this method, it is not necessary to use a gas such as air when separating the master information carrier that has been easily contaminated in the prior art, so that it is not affected at all by the minute contaminants contained in the air. In addition, since the master information carrier and the dummy disk are brought into close contact with each other, the contaminants such as foreign matters existing on the surface of the master information carrier are fixed to the dummy disk by, for example, sinking into the dummy disk side. As a result, the surface of the master information carrier is cleaned.

  Further, in the above method, after placing either one of the master information carrier and the dummy disk on a jig having a concave or convex curved surface and along the curved surface of the jig, the master information carrier and the dummy disk are The other side may be placed on a jig and the master information carrier and the dummy disk may be brought into surface contact.

  Further, in the above method, the master information carrier and the dummy disk may be separated from each other after the master information carrier and the dummy disk are brought into surface contact. In this case, the surface contact and separation between the master information carrier and the dummy disk may be alternately repeated.

  Further, in the above method, after the master information carrier and the dummy disk are brought into surface contact, the master information carrier and the dummy disk are separated by a deformation recovery force when the curved state of the curved master information carrier is released. Also good. By adopting such a method, when the master information carrier and the dummy disk are separated, the master information carrier can be separated by the deformation recovery force of the master information carrier. Conversely, contamination can be prevented and a cleaner surface can be obtained.

  Furthermore, in the above method, the dummy disk may have a structure in which a magnetic plating film is formed on the surface. By doing so, when there are abnormal protrusions on the magnetic film existing on the surface of the master information carrier, the magnetic film in that portion is peeled off when the contact and separation with the dummy disk are repeated. However, since the magnetic plating film is formed on the surface of the dummy disk, the peeled magnetic film adheres to the dummy disk. As a result, the surface of the master information carrier can be more reliably cleaned. As such a magnetic plating film, materials such as Co—Re—P, Co—Ni—P, and Co—Ni—Re—P can be used, for example.

  Further, in the above method, when the master information carrier and the dummy disk are separated from each other, in addition to the deformation recovery force of the master information carrier, nitrogen gas or inert gas is pumped to the interface between the master information carrier and the dummy disk. It may be. In this case, the force for separating is a deformation recovery force, but nitrogen gas or inert gas is used to assist it. Accordingly, the gas flow rate to be pumped may be very small as compared with the conventional case. For this reason, even if ultra-high purity gas is used, there is no problem in terms of cost, the separation operation can be assisted while preventing contamination by the gas, and the separation operation can be performed more stably.

  The cleaning method of the master information carrier of the present invention cleans the master information carrier by bringing the master information carrier into surface contact with the dummy disk so as to move foreign substances on the surface of the master information carrier to the dummy disk side. In the case of separation, the master information carrier itself can be separated by the deformation recovery force. As a result, it is possible to reliably prevent back-contamination due to contaminants contained in a gas such as air for separation, and a master information carrier having a very clean surface state can be stably maintained. As a result, it is possible to realize a magnetic transfer with high yield and low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component and description may be abbreviate | omitted.

  An example of the master information carrier cleaning method according to the embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram for explaining an arrangement configuration of a jig and a dummy disk. 1A is a top view, FIG. 1B is a cross-sectional view thereof, and FIG. 1C is an enlarged cross-sectional configuration diagram of an area A of the dummy disk shown in FIG.

  In FIG. 1, the surface of the jig 1 has a predetermined convex curved surface 2, and the dummy disk 3 is sucked and held on the convex curved surface 2. The dummy disk 3 has a through hole 4 formed at the center thereof, and the cross-sectional structure thereof is such that a magnetic plating film 6 is formed on both surfaces of the dummy disk substrate 5 as shown in FIG. As shown in FIG. 1C, the magnetic plating film 6 deposited on the dummy disk substrate 5 is not limited to being formed on both sides, and may be formed only on one side.

  The jig 1 includes a vacuum suction section 12 having a plurality of openings from the inner periphery to the outer periphery of the convex curved surface 2, a vacuum pipe 14 connected thereto, a valve 16 connected to the vacuum pipe 14, and a first exhaust. An exhaust system on the outer peripheral side that adsorbs and holds a dummy disk composed of a pump 18, a vacuum pipe 20 opened at the center of the convex curved surface 2 and drawn downward, and a valve 22 connected to the vacuum pipe 20. And a second exhaust pump 24 and a central exhaust system. The central exhaust system is further provided with a valve 26 for opening to the atmosphere. Moreover, although the valve | bulb for open | releasing to air | atmosphere similarly may be provided also in the outer peripheral side exhaust system, the structure which is not provided in this Embodiment is shown. In addition, the flow when the exhaust system on the outer peripheral side is exhausted from the vacuum suction unit 12 to the first exhaust pump 18 is indicated by an arrow F.

  FIG. 2 shows a configuration in which the dummy disk 3 is sucked and brought into close contact with the convex curved surface 2 of the jig 1 by operating the outer exhaust system from the state shown in FIG. FIG. This operation is performed by operating the first exhaust pump 18 that is an exhaust system of the dummy disk 3 and opening the valve 16, and sequentially from the inner peripheral hole 121 to the outer peripheral hole 122 of the vacuum suction unit 12. Is adsorbed. The vacuum suction portion 12 is formed as a groove or a hole on the convex curved surface 2 other than the through hole 4 of the dummy disk 3, but this shape may be provided including the outer peripheral region, and the shape, position, etc. Is not particularly limited, and can be set in accordance with the shape of the dummy disk 3.

  FIG. 3 is a diagram showing a state in which the master information carrier 7 is placed on the surface of the dummy disk 3. 3A is a top view thereof, and FIG. 3B is a cross-sectional view thereof. The master information carrier 7 is positioned and placed on the dummy disk 3 in close contact with the jig 1 so that the axis centers of the master information carrier 7 and the dummy disk 3 coincide.

  FIG. 4 is a perspective view for explaining the configuration of the dummy disk 3 and the master information carrier 7 placed opposite thereto. In this perspective view, the jig 1 is omitted. As shown in FIG. 4, the master information carrier 7 has a configuration in which an array pattern 9 formed of a magnetic film is provided on one surface of a base 8. The dummy disk 3 is placed so that one surface on which the array pattern 9 is formed is opposed. The region of the array pattern 9 has a shape protruding from the surface of the substrate 8, and the magnetic film is formed on this protruding surface to constitute the array pattern 9. Therefore, when the master information carrier 7 is evacuated in the central region, the entire surface of the master information carrier 7 is sucked through the gaps between the array patterns 9.

  FIG. 5 is a sectional view showing a state in which the placed master information carrier 7 and the dummy disk 3 are brought into close contact with each other. Since the jig 1 is provided with a central exhaust system different from the suction path of the dummy disk 3, when the second exhaust pump 24 of the exhaust system is operated and the valve 22 is opened, the dummy disk 3 is opened. The gas between the master information carrier 7 and the dummy disk 3 can be exhausted through the through-holes 4, and a suction force F 2 for sucking the master information carrier 7 toward the dummy disk 3 acts. As described with reference to FIG. 4, when the master information carrier 7 is evacuated at the center, the entire surface is sucked through the gaps between the array patterns 9. Further, the convex shape of the dummy disk 3 may be about several μm to several tens μm in an actual design, so that the suction can be sufficiently performed. As a result, both can be brought into close contact with each other.

  In this close contact state, contaminants such as foreign matters existing on the surface of the master information carrier 7 are transferred to the surface of the dummy disk 3, and the surface of the master information carrier 7 is cleaned.

  FIG. 6 is a cross-sectional view showing a state in which the master information carrier 7 and the dummy disk 3 are separated from each other after the surface contaminants are transferred to the dummy disk 3 as shown in FIG. In this case, in order to separate the master information carrier 7 from the dummy disk 3, it is only necessary to close the valve 22 of the central exhaust system and open the valve 26 for opening to the atmosphere. As a result, the suction force F <b> 2 to the master information carrier 7 disappears, so that the deformation recovery force F <b> 3 for returning to the initial flat plate shape acts on the master information carrier 7, and the master information carrier 7 is separated from the dummy disk 3. .

  Note that, when the master information carrier 7 and the dummy disk 3 are brought into close contact with each other, a close contact force due to van der Waals force or the like acts, so that the close contact force can be adjusted to easily cause separation. desirable.

  FIG. 7 is a cross-sectional configuration diagram for explaining a modified example of the master information carrier cleaning method of the present embodiment. In this modified example, the valve 26 of the exhaust system at the center of the jig 10 is not open to the atmosphere, but is connected to high-purity nitrogen gas or inert gas. For this purpose, the exhaust system at the center of the jig 10 is provided with a branch pipe 28 branched from the vacuum pipe 20 drawn downward, and this branch pipe 28 is provided with a valve 26 and nitrogen gas or inert gas. A gas source 30 is attached.

  When the master information carrier 7 is separated, the valve 22 connected to the second exhaust pump 24 is closed and the valve 26 is opened to supply nitrogen gas or inert gas to the interface between the master information carrier 7 and the dummy disk 3. To pump. Thereby, the separation operation can be performed more easily by the effect of the gas fed in addition to the deformation recovery force of the master information carrier 7.

  FIG. 8 is a diagram showing a configuration of a jig and a dummy disk for explaining a method of another modified example of the master information carrier cleaning method according to the present embodiment. FIG. 8A is a top view and FIG. 8B is a cross-sectional view.

  The method of this another modification is characterized in that the surface of the jig 40 has a predetermined concave curved surface 13. Since the configuration other than this is the same as the jig 1 of the embodiment described above, the description thereof is omitted. Further, the step of cleaning the master information carrier using the jig 40 can be performed based on the steps described in the previous embodiment.

  The master information carrier is deformed into a concave shape on the surface of the dummy disk 3, and contaminants such as foreign matter on the surface migrate to the dummy disk 3. When the master information carrier is separated from the dummy disk, it can be separated by the deformation recovery force of the master information carrier by closing the valve 22 and opening the valve 26 to release it to the atmosphere. Even with such a method, cleaning without contamination is possible, and the yield when magnetic transfer is performed using this master information carrier can be improved.

  In the master information carrier cleaning method of the present embodiment, only one operation of bringing the master information carrier and the dummy disk into close contact and then separating them has been described. It is desirable to repeat the separation several times. At that time, if the jig and the dummy disk are kept in close contact with each other and only the master information is brought into close contact with each other, the workability can be improved.

  Furthermore, the convex or concave curved surface of the jig does not specify the curvature of the jig, and when the gas between the jig and the dummy disk is exhausted, the jig and the dummy disk are attracted by the exhaust force and are in close contact with each other. Any curvature may be used as long as a minute gap is formed.

  The master information carrier cleaning method of the present invention can reliably remove contaminants adhering to the surface of the master information carrier, thus preventing defects in magnetic transfer, realizing a high-quality magnetic disk with high yield. And is useful in the magnetic recording field such as HDD.

The figure for demonstrating arrangement | positioning structure of a jig and a dummy disk in the cleaning method of the master information carrier of an example of embodiment of this invention. The figure which shows the structure which attracted | sucked the dummy disk and adhere | attached along the convex curved surface of a jig | tool by operating the outer peripheral side exhaust system from the state shown in FIG. The figure which shows the state which mounted the master information carrier on the surface of a dummy disc in the embodiment The perspective view for demonstrating the structure of a dummy disc and the master information carrier mounted facing this in the embodiment Sectional drawing which shows the state which made the mounted master information carrier and the dummy disc contact | adhered in surface contact in the same embodiment FIG. 5 is a cross-sectional view showing a state in which the master information carrier and the dummy disk are separated after the surface contaminants are transferred to the dummy disk as shown in FIG. Sectional block diagram for demonstrating the method of the modification in the cleaning method of the master information carrier of the embodiment The figure which shows the structure of the jig and dummy disk for demonstrating the method of another modification in the cleaning method of the master information carrier concerning the embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10,40 Jig 2 Convex-curved surface 3 Dummy disk 4 Through-hole 5 Dummy disk base | substrate 6 Magnetic plating film | membrane 8 Base | substrate 9 Arrangement pattern 12 Vacuum suction part 13 Concave-curved surface 14, 20 Vacuum piping 16, 22, 26 Valve 18 1st Exhaust pump 24 Second exhaust pump 28 Branch pipe 30 Gas source

Claims (7)

A method of cleaning a master information carrier for magnetic transfer in which an array pattern corresponding to a predetermined information signal is formed on a substrate surface with a magnetic film,
By bending the surface of the master information carrier on which the magnetic film is formed and the dummy disk into a concave shape or a convex shape, and bringing the surface of the master information carrier into contact with the dummy disk, the master information is obtained. A method of cleaning a master information carrier, wherein the surface of the master information carrier is cleaned by transferring contaminants on the surface of the carrier to the dummy disk side. After placing either one of the master information carrier and the dummy disk on a jig having a concave or convex curved surface and along the curved surface of the jig, the master information carrier and the dummy disk 2. The master information carrier cleaning method according to claim 1, wherein the other is placed on the jig, and the master information carrier and the dummy disk are brought into surface contact. 3. The method for cleaning a master information carrier according to claim 1, wherein after the master information carrier and the dummy disk are brought into surface contact, the master information carrier and the dummy disk are separated from each other. 4. The method for cleaning a master information carrier according to claim 3, wherein surface contact and separation between the master information carrier and the dummy disk are alternately repeated. After bringing the master information carrier and the dummy disk into surface contact, the master information carrier and the dummy disk are separated by a deformation recovery force when the curved state of the curved master information carrier is released. 5. A method for cleaning a master information carrier according to claim 3 or 4. 6. The master information carrier cleaning method according to claim 1, wherein a magnetic plating film is formed on a surface of the dummy disk. When separating the master information carrier and the dummy disk, in addition to the deformation recovery force of the master information carrier, nitrogen gas or an inert gas is pumped to the interface between the master information carrier and the dummy disk. 7. The method for cleaning a master information carrier according to claim 3, wherein the master information carrier is cleaned.

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