JP2003173657A - Cleaning method of master carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method of master carrier which allows the magnetic transfer of high transfer quality or the optical disk molding of high molding precision to be continued by removing depositions to a master carrier when the deposition of foreign matter thereto is partial and slight. <P>SOLUTION: When a magnetic field for transfer is impressed by closely adhering the master carrier 3 carrying transfer information with a slave medium 2 which is transferred and a magnetized pattern associated with the transfer information is transferred and recorded to the slave medium 2, the slave medium 2 after the magnetic transfer is subjected to the verification of the magnetized pattern by a verification device 4, based on the verification, the surface of the master carrier 3 of the part corresponding to an error-generating position is selectively cleaned by a cleaning device 5, the depositions are removed and the magnetic transfer is effectively continued. Further, likewise with respect to the master carrier for optical disk, it is preferable that the verification of the optical disk after molding is performed, the surface of the surface of the master carrier of the part corresponding to an error-generating position is selectively cleaned and the depositions are removed. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a magnetic transfer master carrier used for magnetic transfer or an optical disk master carrier used for molding an optical disk. 2. Description of the Related Art In a magnetic transfer method, an information carrying surface of a master carrier carrying transfer information by a fine concavo-convex pattern of a magnetic material is in close contact with a slave medium having a magnetic recording portion that receives the transfer. A magnetic field for transfer is applied to a slave medium to transfer and record a magnetization pattern corresponding to transfer information (for example, a servo signal) carried on the master carrier. As this magnetic transfer method, for example, JP-A-63-1
No. 83623, JP-A-10-40544, JP-A-10-26966, and the like. By the way, at the time of magnetic transfer by the above magnetic transfer method, the master carrier is contaminated with foreign matters attached to the surface according to repeated use of the master carrier. The deposits on the master carrier are mainly dust and fiber waste generated in the surrounding environment. When magnetic transfer is performed with these deposits attached to the master carrier, the master carrier and the slave medium cannot be kept in close contact up to the periphery of the attached portion, and pattern transfer at a predetermined signal level is not possible. The transfer quality is deteriorated. When the recorded signal is a servo signal, there is a problem that the tracking function is not sufficiently obtained and the reliability is lowered. [0005] By repeating the adhesion between the master carrier and the slave medium, the adhered matter promotes the adhesion force to the surface of the master carrier, and all of the subsequent magnetically transferred slave media have the same or higher pattern transfer defects. And causes a large number of defective products. Furthermore, there is a problem that the surface of the master carrier is deformed by these deposits and the normal function is impaired. From the above point, for example, Japanese Patent Laid-Open No. 2000-285.
As seen at 637, it has been proposed to clean the magnetic transfer master carrier. In the cleaning, the cleaner disk to which the cleaner pad is attached is rotated and brought into contact with the surface of the rotating master carrier to remove the adhered matter. On the other hand, the stamper method for producing an optical disk is a method in which a resin layer of an optical disk is formed by using an optical disk master carrier (so-called stamper) carrying information by an uneven pattern. An optical disk is formed by coating a thin film reflective layer on the surface of a resin layer having a concavo-convex pattern corresponding to information, and further providing a protective layer. Since the optical disk master carrier is continuously formed without cleaning the optical disk master carrier during the molding, when the number of molded articles exceeds 1000, foreign matter adheres like the magnetic transfer master carrier. Along with this, the error rate of the produced optical disk tends to increase, making it difficult to manufacture a highly reliable optical disk. From the above point, for example, Japanese Patent Laid-Open No. 5-14409.
7, it has been proposed to clean the optical disk master carrier. For the cleaning, electrolytic degreasing cleaning, ultrasonic cleaning using a detergent, an ozone cleaning device, and the like were used, but there were cases in which the firmly adhered deposits could not be removed. Even when the master carrier is cleaned as described above, if the magnetic transfer is repeated while being in close contact with the slave medium, or if the optical disk is repeatedly formed, the master carrier is surrounded by the surrounding environment. It is inevitable that foreign matter such as dust and fiber waste generated in However, cleaning at each magnetic transfer or molding leads to a decrease in transfer efficiency or molding efficiency, and it is preferable to perform cleaning after a predetermined number of times of magnetic transfer or molding. Defects or molding defects may occur, and a large amount of defective products may be generated as described above. At that time, there is a case in which foreign matter is partially attached to the master carrier, and transfer failure or molding failure may occur only in the portion corresponding to the attached portion. If the attached matter is removed, magnetic transfer or There is a possibility that the optical disc molding can be continued. The present invention has been made in view of such problems. When the foreign matter adheres to the master carrier partially and lightly, the adhered matter is removed to obtain a magnetic transfer with high transfer quality or an optical disc with few errors. It is an object of the present invention to provide a method for cleaning a master carrier in which the molding can be continued. The cleaning method of the present invention is a cleaning method for a magnetic transfer master carrier or an optical disk master carrier, which is formed on a slave medium after magnetic transfer or an optical disk after molding. The pattern is verified, and the surface of the master carrier corresponding to the error occurrence position is selectively cleaned to remove the deposits. The magnetic transfer master carrier is cleaned by applying a magnetic field for transfer by bringing the master carrier carrying the transfer information into close contact with the slave medium receiving the transfer, and transferring the magnetization pattern corresponding to the transfer information to the slave medium. A method of cleaning the master carrier used for magnetic transfer to be recorded, wherein a verification inspection of the magnetization pattern of the slave medium after magnetic transfer is performed, and a surface of the master carrier corresponding to an error occurrence position is selectively selected. It is characterized by removing the deposits by cleaning. A method for cleaning an optical disk master carrier is a method of cleaning the master carrier used for forming an optical disk by an information-carrying master carrier to form a concavo-convex pattern on the optical disk. A verification test of the concave / convex pattern of the optical disc is performed, and the surface of the master carrier corresponding to an error occurrence position is selectively cleaned to remove deposits. The selective cleaning described above is performed by partial irradiation of an excimer laser, or by spraying a high-pressure jet stream or fine particles of dry ice, or by pressing a cleaning roller or cleaning sheet having weak adhesiveness. It is preferable that the cleaning is performed by wiping with a cleaning cloth, or by partial cleaning such that the glide head is brought close to the surface of the rotating master carrier at a predetermined interval. The verify inspection process is to inspect a magnetized pattern such as a transferred servo signal or a formation pattern of a molded optical disk. A slave medium or an optical disk is loaded in a drive, and a magnetic head or a laser pickup is accessed. Then, the pattern recorded on the slave medium or the optical disk is read to inspect the signal quality. The location of the error is determined from the track number, sector number, etc., and the information is sent to the cleaning device to clean the corresponding part. In addition, as the cleaning, one that performs ultrasonic cleaning partially can be employed. Cleaning may be performed on the master carrier set in the magnetic transfer device or the molding device, or may be performed by removing the master carrier from the magnetic transfer device. After the partial cleaning, the entire master carrier may be cleaned. The cleaning includes liquid cleaning with megasonic vibration by an ultrasonic cleaning head, ultrasonic vibration cleaning, electrolytic degreasing cleaning, and ultrasonic vibration in a cleaning tank liquid or air with an ultrasonic vibration head. Spraying, glide cleaning with a glide head with a width larger than the track width,
Ultrasonic cleaning after glide cleaning, incineration cleaning by excimer laser irradiation, plasma cleaning, etc. can be used. Note that it is preferable to perform glide cleaning with the flying height of the glide head being 40 nm or less. In addition, the entire cleaning of the master carrier as described above,
A new master carrier may be applied before being set in the magnetic transfer device or the molding device. Furthermore, the master carrier set in the transfer device or the molding device may be cleaned before being in close contact with the slave medium or before closing the mold. As the cleaning, it is possible to apply a spray of gas given ultrasonic vibration, a spray of ion wind (static charge air) or clean air, and an ultrasonic cleaning head may be used. According to the present invention as described above, a verification inspection of the formation pattern of the slave medium after magnetic transfer or the optical disk after molding is performed, and the surface of the master carrier corresponding to the error occurrence position is checked. When the magnetic transfer is repeated with the slave medium in close contact with the slave medium, or when optical disc molding is repeated, transfer defects or molding defects occur due to adhesion of foreign matter, etc. When a slave medium or optical disc sampling verification is detected, foreign matter is partially attached to the master carrier, and an error occurs when transfer failure or molding failure occurs only in the portion corresponding to the attached portion. By identifying the part and focusing on the cleaning of the corresponding part, the deposits can be removed efficiently, and every magnetic transfer. Alternatively, an error occurrence portion can be repaired without performing cleaning for each molding, and good magnetic transfer or optical disc molding can be continued without generating a large amount of defective products, thereby improving productivity. Further, if the entire portion is cleaned after the defective portion is intensively cleaned by the partial cleaning, the foreign matter can be completely removed, and the subsequent occurrence of the failure can be satisfactorily prevented. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail below. FIG. 1 is a diagram showing a system for cleaning a magnetic transfer master carrier according to one embodiment of the present invention, and FIG. 2 is a diagram showing a system for cleaning an optical disk master carrier according to another embodiment. . In FIG. 1, a magnetic transfer apparatus 1 includes a master carrier 3 for magnetic transfer carrying transfer information such as servo signals.
And a slave medium 2 to be transferred are brought into close contact with each other, a magnetic field for transfer is applied, and a magnetization pattern corresponding to transfer information is transferred and recorded on the slave medium 2. The slave medium 2 after the magnetic transfer is taken out from the magnetic transfer apparatus 1 and carried out to the next process. A part of the slave medium 2 is periodically taken out, and a magnetic pattern such as a servo signal transferred by the verify inspection apparatus 4 is inspected. I do. This verification inspection device 4 loads the slave medium 2 into the drive,
The magnetic head is accessed to read a servo signal or the like recorded on the slave medium 2 to inspect the signal quality. If an error has occurred as a result of the inspection, the location of the error is determined from the track number, sector number, etc., and the information is sent to the cleaning device 5. The cleaning device 5 selectively cleans a corresponding portion where an error has occurred in the master carrier 3 used for magnetic transfer, and removes deposits. Further, it is preferable that the master carrier 3 before being set in the magnetic transfer apparatus 1 is cleaned on the entire surface to remove the deposits on the entire surface. Further, after the selective cleaning by the cleaning device 5, the whole surface cleaning may be performed and then set. Next, in FIG. 2, an optical disk molding apparatus 6 sets an optical disk master carrier 7 carrying information with fine concave and convex shapes in a mold, and injects resin to mold a resin layer of the optical disk 8. A fine uneven pattern is formed on the surface. The molded optical disk 8 is taken out from the molding apparatus 6 and carried out to the next process. A part of the optical disk 8 is periodically extracted, and the pattern formed by the verify inspection apparatus 9 is inspected. This verify inspection apparatus 9 is provided with an optical disc 8
Is loaded into the drive, and a laser pickup is accessed to read a pit signal formed on the optical disk 8 to inspect the signal quality. If an error has occurred as a result of the inspection, the location where the error has occurred is determined from the track number, sector number, etc., and the information is stored in the cleaning device 10.
To send. In this cleaning device 10, the corresponding portion where an error has occurred in the master carrier 7 used for molding is selectively cleaned to remove deposits. Further, it is preferable to clean the entire surface of the master carrier 7 before being set in the molding apparatus 6 to remove the deposits on the entire surface. Further, after the selective cleaning by the cleaning device 10, the entire surface cleaning may be performed and then set. The cleaning devices 5 and 10 in both the above-described embodiments correspond to, for example, an excimer laser to the error occurrence portion for the master carriers 3 and 7 in the used state set in the magnetic transfer device 1 or the molding device 6. The deposits are removed by irradiating the relevant parts or spraying fine particles of high-pressure jet flow or dry ice. Further, a cleaning sheet having a weak adhesive surface with silicon rubber or the like may be pressed against the master carrier 3 or 7 in a stamp shape on a corresponding portion corresponding to the error occurrence site to remove the deposits. Other cleaning devices 5 and 10 include:
Deposits on the master carriers 3 and 7 are rolled by pressing a cleaning roller whose surface is weakly adhesive with silicon rubber or the like at a radial position corresponding to an error occurrence site on the surfaces of the rotating master carriers 3 and 7. May be removed by adhering to the surface of the cleaning roller. Alternatively, the deposit may be removed by wiping the relevant part using a cleaning cloth made of fine fibers. As another cleaning device 5, 10, the glide head is brought close to a radial position corresponding to an error generating portion on the surface of the rotating master carrier 3, 7 at a predetermined interval (for example, 40 nm or less). Alternatively, it may be configured to remove deposits. In addition, a device that performs ultrasonic cleaning partially may be used. The selective cleaning described above is preferably performed on the master carriers 3 and 7 set in the magnetic transfer device 1 or the molding device 6.
Or you may make it remove the master support | carriers 3 and 7 from the shaping | molding apparatus 6. Before setting the magnetic transfer device 1 or the molding device 6 or after partial cleaning, it is applied to the master carriers 3 and 7 removed from the magnetic transfer device 1 or the molding device 6 for replacement. As a method for cleaning the entire surface, a cleaning method using a liquid or gas subjected to ultrasonic vibration or megasonic vibration can be used. At that time, there are a type in which a liquid or gas is sprayed from a cleaning head and a type in which a liquid is put into a cleaning tank and the cleaning liquid or master carrier is vibrated. In addition, electrolytic degreasing cleaning can also be used, and deposits may be removed by using a glide head so as to be close to the surface of the rotated master carrier at a predetermined interval, for example, 40 nm or less. Ultrasonic cleaning may be performed after the glide treatment. The deposits may be burned and removed by irradiation with an excimer laser, or may be burned and removed using plasma discharge (reactive gas, gas plasma, photoexcited gas) in a reduced pressure reactive gas atmosphere. Further, ion wind or clean air may be blown onto the master carriers 3 and 7 immediately before close contact with the slave medium 2 or immediately before mold closing.
The entire surface cleaning and the partial cleaning after the verification inspection may be used as a cleaning device. Specifically, the magnetic transfer device 1 shown in FIG. 1 is a presser for bringing the slave medium 2 into close contact with the master carrier 3 at the transfer position with the center position aligned with the master fixing base holding the master carrier 3. A holder having a member;
An adhesion means for applying an adhesion force and a magnetic field application device for applying a transfer magnetic field while rotating the holder are provided. As the slave medium 2, a disk-shaped magnetic recording medium such as a hard disk having a magnetic recording portion (magnetic layer) formed on both sides or one side, a high-density flexible disk, or the like is used. The slave medium 2 may also be cleaned before being set in the magnetic transfer apparatus 1. The magnetic transfer master carrier 3 is formed on a disk-shaped disk. In this master carrier 3, a soft magnetic material is coated on a fine concavo-convex pattern formed on a substrate, and this surface becomes an information carrying surface having a transfer pattern in close contact with the slave medium 2. When performing magnetic transfer, the slave medium 2 is preliminarily magnetized in advance in the in-plane track direction for in-plane recording and in the vertical direction for perpendicular recording. The slave medium 2 is brought into close contact with the master carrier 3, and magnetic transfer is performed by applying a transfer magnetic field in a track direction or a vertical direction substantially opposite to the initial DC magnetization direction. The magnetic transfer apparatus 1 performs magnetic transfer to a plurality of slave media 2 using the same master carrier 3. First, the master carrier 3 is placed on a master fixing base.
Are held in alignment. In the open state in which the holding member of the holder is spaced apart from the master fixing base, the initially magnetized slave medium 2 is set with the center position aligned,
The pressing member is moved closer to the master fixing base, and the slave medium 2 and the master carrier 3 are brought into close contact with a predetermined close contact force by the close contact means. After that, the magnetic field application device is moved closer, the magnetic field for transfer is applied by the magnetic field application device while rotating the holder, and the magnetization pattern corresponding to the transfer pattern of the master carrier 3 is transferred and recorded on the magnetic recording portion of the slave medium 2. That is, the magnetic field for transfer applied at the time of magnetic transfer is sucked into the convex pattern by the soft magnetic material in close contact with the slave medium 2 in the transfer pattern of the master carrier 3, and in the case of in-plane recording, the initial magnetization of this part is In the case of perpendicular recording, the initial magnetization of this portion is reversed and the initial magnetization of the other portion is not reversed. As a result, the slave medium 2 has a transfer pattern of the master carrier 3. The corresponding magnetization pattern is transferred and recorded. After the magnetic transfer, the verification inspection device 4 performs a sampling verification inspection of the slave medium 2,
The error generating part of the master carrier 3 is cleaned with the cleaning device 5.
Clean more carefully and clean the whole as needed. The next slave medium 2 is carried in and the same magnetic transfer is repeated thereafter. On the other hand, the optical disk master carrier 7 shown in FIG.
The (stamper) is formed on a disk-like disk and is composed of a metal plate such as Ni having a fine uneven pattern formed on the surface, and this surface becomes a molding surface (information carrying surface). When optical disk molding is performed, the master carrier 7 is set on one inner surface of the open / close mold of the molding apparatus 6, the mold is closed and molten resin is injected, and the fine uneven pattern of the master carrier 7 is formed. The resin layer of the optical disk 8 having an uneven shape obtained by inverting the uneven shape is formed. This molding device 6
Then, a plurality of optical disks 8 are formed by the same master carrier 7. After the molding, the verify inspection device 9
The optical disk 8 is extracted and verified, and the error occurrence portion of the master carrier 7 is intensively cleaned by the cleaning device 10, and the whole is cleaned as necessary. Thereafter, the optical disc molding is repeated in the same manner. According to the embodiment of the present invention as described above,
When the magnetic transfer is repeated while being in close contact with the slave medium 2 or when the molding of the optical disk 8 is repeated, when the transfer failure or molding failure occurs due to adhesion of foreign matter to the master carriers 3 and 7, the slave medium 2 or optical disc 8 is detected by sampling verification, the location where the error occurs is identified, and the corresponding portion is selectively and heavily cleaned, and the portion where the error has occurred is repaired without cleaning every magnetic transfer or molding. Thus, productivity can be improved because magnetic transfer or molding is continued.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a system of a magnetic transfer master carrier cleaning method according to one embodiment of the present invention. FIG. 2 is an optical disk master carrier according to another embodiment. FIG. 1 is a diagram showing a system of a cleaning method. DESCRIPTION OF SYMBOLS 1 Magnetic transfer device 2 Slave medium 3 Master carrier 4 for magnetic transfer 4, 9 Verify inspection device 5, 10 Cleaning device 6 Optical disc molding device 7 Master carrier for optical disc

Claims (1)

What is claimed is: 1. A method for cleaning a magnetic transfer master carrier or an optical disk master carrier, comprising: performing a verify inspection of a pattern formed on a slave medium after magnetic transfer or an optical disk after molding; A method for cleaning a master carrier, wherein the surface of the master carrier corresponding to an error occurrence position is selectively cleaned to remove deposits.