JPH09262733A - Holding device for stamper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix a stamper on a holding table with the stamper kept on a plane by a method wherein the position of a magnet arranged at the holding table is set to a position deviated from an uneven surface information forming position on the surface side of the stamper. SOLUTION: A magnet 4 holding a stamper 5 on the surface of a holding table 2 is set in the specified position of the stamper 5. The specified position is a position deviated from an uneven surface information forming part 6 on the surface side of the stamper 5, namely, usually a part equivalent to the stamper 5 further outside than the uneven surface information forming part 6. By arranging the magnet 4 in this position, even when fine metals floating in an electroforming tank and a washing tank are attracted to the magnet 4, a part to which the fine metals are adhered is the outer edge part of the stamper 5, and a defect is prevented from occurring due to adhesion of the fine metals to the uneven surface position on the surface side of the stamper 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding and fixing device for holding a master in a step of processing a master such as an optical disk stamper.

[0002]

2. Description of the Related Art A master used as a mold for manufacturing an optical disk substrate by injection molding is usually manufactured as follows. That is, after a photosensitive layer coated with a photosensitive resin on a clean and flat glass plate that has been polished is irradiated with a laser beam that is finely focused by an objective lens based on a fine shape corresponding to a preformat to be formed. Then, it is developed with an alkali developing solution, and the exposed portion is removed to form a resin master having fine pits and / or grooves.

A conductive nickel thin film or the like is formed on the surface of the resin master by sputtering or the like, and then nickel is deposited by performing wet electroforming in an electrolytic solution containing nickel ions, and then glass having the resin master. By peeling off the nickel portion from the plate, a stamper (master) for optical disks having fine irregularities on the surface and a thickness of the order of 100 microns is manufactured.

Since the photosensitive resin used in the above steps remains on the surface of the stamper as it is separated from the glass plate, the photosensitive resin is usually removed with an alkaline cleaning liquid. . In addition, after the stamper thus produced is subjected to an appropriate surface treatment, the surface is directly electroformed from a nickel ion solution so that one stamper has a fine shape in a mirror image relationship with the stamper. Stamper replication has also been performed, in which a plurality of stampers are manufactured, and then each of them is used as a template to manufacture a plurality of stampers having the same fine shape as the first stamper.

The fine shape formed on the stamper, that is, the size of the pits and / or grooves is very small, on the order of submicrons, and further finer patterns are required due to the recent increase in the density of optical discs. Therefore, in each of the above steps, it causes a defect in the fine pattern formed on the stamper,
Consequently, removing minute dust on the surface of the stamper, which can deteriorate the characteristics of the disc, is extremely important in producing the optical disc.

On the other hand, among the above-mentioned steps, there is a step in which the stamper must be held and fixed to a specific portion of the processing apparatus during the processing. For example, during electroforming when making a duplicate stamper, hold the stamper in a tip jig for supplying a negative voltage to the stamper in an electrolytic solution containing nickel ions, and make it uniform in thickness over the entire surface. Is electroformed while rotating the stamper so that

At that time, it is essential that the stamper is held in a flatly fixed state so as not to be warped due to its own stress. Therefore, a suitable stamper holding and fixing method of a magnet system is required. Has been done. Further, for example, the stamper surface cleaning device is used for removing the photosensitive resin and cleaning fine dust on the stamper surface as described above. As a specific cleaning method, the stamper is held and fixed on the rotary stage. Then, while rotating the stage, cleaning is performed by ejecting a cleaning liquid such as the above alkaline cleaning liquid or ultrapure water onto the stamper surface from the nozzle, and finally the stage is rotated at high speed to shake off the liquid on the stamper surface. It is removed by drying.

The stamper surface cleaning method using the stamper surface cleaning device adopting such a method of rotating the stamper is very excellent in that it is difficult to leave stains or the like on the surface of the stamper due to minute dust or liquid. For example, even after the stamper is immersed in a liquid tank and subjected to cleaning treatment by other methods such as ultrasonic cleaning, stains due to the liquid remain on the stamper surface just by air-drying as it is. If the surface of the stamper is washed and dried before the surface is dried, the stain and the like caused by the liquid can be avoided.

[0009]

Generally, in various processing steps of a stamper, it is sometimes necessary to hold and fix the stamper in a state of being kept flat. It is suitable because it is easy to attach and detach, and the stamper can be easily kept in a stable flat shape by using a flat magnet or embedding the magnet in a flat mounting stage. Can be said to be

As a method of holding and fixing the stamper, a method of sandwiching the stamper with a screw type jig through a hole formed in the center of the stamper can be considered in addition to the method of using a magnet. In this case, a boundary portion between the screw and the stamper is used. Foreign matter such as minute metal pieces formed by scraping the stamper easily sticks to the surface of the stamper.In addition, for example, it is possible to fix it by sandwiching the outer periphery of the stamper from above and below at several places. Has a problem that it is difficult to maintain the flatness of the stamper because the thin stamper surface is easily distorted and it is difficult to fix the stamper flatly.

Combining these viewpoints, as a fixing method for holding and fixing the stamper while maintaining the flatness of the stamper during various stamper treatments, the stamper can be easily fixed while maintaining a stable planar shape, and the stamper can be fixed. It can be said that the method of fixing from the backside of the stamper with a magnet, which does not form a contact portion with the stamper on the upper surface, that is, the side of the finely-shaped recording surface, is the most preferable.

In the stamper fixing method using a magnet, it is possible to embed a disk-shaped magnet having the same size as that of the stamper in the flat plate stage or use a flat plate stage made of a disk-shaped magnet and to fix the back surface of the stamper by suction. However, since the thickness of the stamper is usually thin, on the order of 100 microns, for example, the stamper is firmly held even during the high-speed rotation required to shake off and dry the stamper (for example, rotation speed of the order of 1,000 rpm). It is unavoidable that the magnetic force of a magnet having such strength reaches the upper surface of the stamper, that is, the recording surface side.

As a result, of the fine dust that is unavoidably contained in the cleaned ambient air around the apparatus or in the cleaning liquid and is contained in a very small amount, metal-derived dust is generated by the magnetic force of the stamper fixing magnet. There is a case where minute defects are generated on the stamper surface by being suction-adsorbed and left on the recording surface of the stamper.

[0014]

In order to solve the above problems, the present invention uses a magnet for holding and fixing the stamper in the process of processing the stamper (master disc) for an optical disk, and the magnet has a special arrangement. It was found that the problem could be solved by the above, and the present invention was completed.

That is, the gist of the present invention is a device for holding a master disk made of a magnetic material having surface irregularity information on a holding table with a magnet from the back side thereof, and the position of the magnet provided on the holding table. Is located at a position deviated from the position on the front side of the master where the concave-convex information is formed. By fixing the stamper on the flat plate stage using the magnet having such a shape, it is possible to hold and fix the stamper on the flat plate stage while keeping the stamper stable and flat.

Further, minute foreign matter such as cutting dust generated by contact between the stamper and the jig is not generated on the upper surface of the stamper, that is, on the recording surface side. It is possible to solve the problem of the magnetic attraction and fixation method, in which minute foreign matter is attracted to the information recording part of the stamper,
And so on. Hereinafter, an example of the apparatus of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a perspective view of an example of the apparatus of the present invention. FIG. 2 is a vertical sectional view of an example of the apparatus of the present invention. FIG. 3 is a vertical sectional view of an example of the apparatus of the present invention. Is a holding table, 3 is an axis, 4 is a magnet, 5 is a master, 6 is an unevenness information forming portion, 7 is a groove for peeling the master, 8 is a through hole, 9 is a magnet moving member, 10 is a spring, 11 is a pressing member. Shown respectively.

The master holding device 1 is usually a disc-shaped holding table 2
It has a structure in which a shaft 3 is provided on the back surface of the base, and the master 5 is held on the surface of the holding table 2, and the shaft 3 is used as a handling device that rotates in an electroforming tank or a cleaning tank to perform various treatments. To be In the master holding device 1 of the present invention, a magnet is used as a method of holding the master 5 on the surface of the holding table 2. The magnet 4 is characterized by being installed at a specific position on the master 5.

The specific position means a position deviated from the unevenness information position on the front side of the master 5 which is attracted to the holding table 2. Usually, as shown in the figure, the unevenness information forming portion 6 is formed in a ring shape on the front side of the master 5. Therefore, it means a position deviated from the unevenness information forming section 6, that is, a portion corresponding to the master 5 usually outside the unevenness information forming section 6. By installing the magnet 4 in such a position, even if the fine metal floating in the electroforming tank or the cleaning tank is adsorbed by the magnet 4, the fine metal adheres to the outer edge portion of the master 5, and There is an excellent effect that fine metal does not adhere to the unevenness information position on the front side of No. 5 to cause a defect at the unevenness information position.

The figure shows a structure in which a plurality of magnets 4 are arranged in an annular shape, but a structure in which an annular (ring-shaped) magnet 4 is embedded may be used, and the structure is arbitrary. Further, as shown in FIG. 3, the magnet 4 is movably fitted into a hole provided in the holding table 2, and the lever-shaped magnet moving member 9 urged by the spring 10 is operated by the pressing member 11. By making the magnet 4 retractable from the surface of the holding table to weaken the attraction force to the master 5 and remove the master 5, the master 5 should be unnecessarily bent when the master 5 is removed. There is no and is preferable.

The surface of the holder 2 corresponding to the unevenness information forming portion 6 of the master 5 is made smooth, and the portion corresponding to the unevenness information forming portion 6 of the master 5 is held in close contact with the surface of the holder 2. As a result, deformation of the master 5 during processing is prevented, and good electroforming and cleaning are performed. When the master 5 having an opening at the center is used, the surface of the holding table 2 may be provided with a centering projection or the like that matches the opening, but there is also a master 5 having no opening at the center. Since it can be applied to various masters 5, normally, no protrusion for centering is provided.

It is convenient to remove the master 5 by providing through holes 8 through the front and back of the holding table 2. A rod-shaped jig is inserted from the back side of the through hole 8 and the master 5 is pushed up and held. It suffices to lift it from the surface of the table 2 and pinch it with fingers to remove it. When the through hole 8 is provided, it is preferable to provide the through hole 8 outside the portion corresponding to the unevenness information forming portion 6 of the master 5 in order to prevent deformation of the unevenness information forming portion 6.

Further, a structure is also conceivable in which a master disc peeling groove 7 is provided at a position corresponding to the outer edge portion of the master disc 5 of the holding table 2 and the master disc 5 is peeled by fingers. Even when the master disc peeling groove 7 is provided, it is preferable to provide it on the outside of the portion corresponding to the concavo-convex information forming portion 6 of the master disc 5 in order to prevent deformation of the concavo-convex information forming portion 6.

[0024]

According to the apparatus of the present invention, the stamper (master disc) can be fixed to the holding table while being kept flat, and the magnet fixing means that minute foreign matter is adsorbed on the uneven information forming portion of the stamper. This is a master holding device that solves the problems of the device and has a great practical effect.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a device of the present invention.

FIG. 2 is a vertical sectional view of an example of the device of the present invention.

FIG. 3 is a longitudinal sectional view of an example of the device of the present invention.

[Explanation of symbols]

 1 master holding device 2 holding base 3 axis 4 magnet 5 master 6 concave / convex information forming part 7 plate peeling groove 8 through hole 9 magnet moving member 10 spring 11 pressing member

Claims (4)

[Claims] 1. A device for holding a master, which is made of a magnetic material and whose surface has irregularity information, on a holding table with a magnet from the back side thereof, wherein the position of the magnet provided on the holding table is set on the front side of the master. A master holding device, characterized in that the position is deviated from the unevenness information forming position. 2. The surface of the holding table at the portion corresponding to the concave-convex information forming position of the master is made smooth, and the portion corresponding to the concave-convex information forming position of the master is held in close contact with the surface of the holding table. The master holding device according to claim 1. 3. The master disk holding device according to claim 2, wherein a master disk peeling groove is provided on the surface of the holder outside the portion corresponding to the position where the master disk unevenness information is formed. 4. The magnet provided on the holding table is retractable from the surface of the holding table.
4. The master holding device according to any one of 3 to 3.