JPH0250994A - Production of stamper for duplicating optical disk and duplicating method for optical disk - Google Patents

Abstract

PURPOSE:To produce a double-sided stamper which is excellent in parallelism and utilized for duplicating an optical disk by laminating the metallic film sides of two glass base plates on which the metallic films are deposited and formed by a normal method with thermosetting resin and thereafter peeling the glass base plates. CONSTITUTION:A photoresist film is applied on the surface of a glass base plate and an uneven fine pattern is formed on this film. After an electrically- conductive film is formed on the surface of this pattern, a metallic film is deposited and formed on this film by an electroforming method. Two sheets of glass base plates on which the metallic films have been deposited and formed by such a way are prepared and the metallic film sides are laminated with thermosetting resin (about 3000kg/cm<2> flexural modulus of elasticity) and the respective glass base plates are peeled to obtain a double-sided stamper. Thereby the stamper excellent in parallel properties is obtained and deformation of the stamper is not caused in the case of duplicating an optical disk and thereby a high-quality optical disk can be duplicated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a technique for manufacturing a replica of an optical information recording medium, and more specifically to a method for manufacturing a stamper for duplicating an optical disk and a method for duplicating an optical disk.

Conventional technology Conventionally, in the production of a stamper for optical disk duplication, a photoresist film is applied on the surface of a glass substrate, a concavo-convex fine pattern is formed on this photoresist film, and a conductive film is coated on the surface of this fine pattern. After forming, a metal film is deposited on the conductive film by electroforming, and this metal film is peeled off from the glass substrate to obtain a stamper.

When such a stamper is used as a stamper for injection molding, first, the surface on which the metal film is deposited is polished by lapping or polishing to make the thickness of the stamper uniform and to give it a mirror finish. Then, this polished surface is attached to a mold of an injection molding machine, molten resin is injected, and the mold is tightened, thereby producing a duplicate optical disc.

Problem to be Solved by the Invention In this case, the stamper is deformed due to mold clamping pressure, temperature difference between the mold and molten resin, molten resin pressure, etc., and the quality (signal characteristics, etc.) of the optical disc obtained by molding is affected. This has forced a decline in yield.

Means for Solving the Problem In the invention as set forth in claim 1, a photoresist film is applied on the surface of a glass substrate, a concavo-convex fine pattern is formed on the photoresist film, and a conductive film is formed on the surface of the fine pattern. After forming a conductive film, a metal film is deposited and formed on the conductive film by electroforming, and the metal film is peeled off from the glass substrate to obtain a stamper. Two precipitated glass substrates are prepared, their metal coating sides are bonded together with a thermosetting resin, and then each glass substrate is peeled off to obtain a double-sided stamper.

In the invention as claimed in claim 2, the double-sided stamper according to the invention as claimed in claim 1 is used, the double-sided stamper is fixed at the center of an injection molding machine, and the same amount of melt is applied to both stamper surfaces of the double-sided stamper at the same time. After injecting the resin, the molds of the injection molding machine are simultaneously clamped onto each stamper surface to duplicate the optical disc.

According to the invention described in claim 1, two glass substrates on which metal coatings have been precipitated are prepared, their metal coating sides are bonded together with a thermosetting resin, and then each glass substrate is peeled off. Since a double-sided stamper is obtained, a stamper with better parallelism can be obtained than when a stamper is obtained by peeling off a metal coating deposited on only one glass substrate from the glass substrate.

According to the invention as claimed in claim 2, the double-sided stamper as claimed in claim 1 with good parallelism is used (1), this is fixed at the center of an injection molding machine, and the same amount is applied to both stamped N faces at the same time. After injecting the molten resin, each stamper surface is simultaneously clamped with the mold of the injection molding machine to duplicate the optical disc, so there is no deformation of the stamper during molding, and the double-sided stamper is Parallelism can be maintained and high quality optical discs can be duplicated.

Example 1 Example 1 of the present invention will be described with reference to FIGS. 1 and 2. First, a photoresist film is applied onto the surface of a glass substrate, and a fine pattern with concave and convex portions is formed on this photoresist film. After forming a conductive film on the surface of this fine pattern, a metal film of Ni is deposited to a thickness of 150 μm on the conductive film by electroforming. In this example, two glass substrates on which Ni metal coatings are deposited in this manner are prepared. Then, the two glass substrates are bonded with a thermosetting resin with a bending elastic modulus of 3000 kg/- on the metal coating side, and after the resin is completely cured, the glass substrates on both sides are peeled off and a double-sided stamper is attached. obtain. In Figure 1,
A double-sided stamper 1 obtained in this way is shown. That is,
Metal coatings 3 and 4 made of Ni are present on both sides of the completely cured thermosetting resin 2. At this time, the double-sided stamper 1 had good parallelism of 0.1 μm or less.

Such a double-sided stamper 1 is fixed at the center of an injection molding machine 5 as shown in FIG. 1(a). Then, the molten resin supply valves 6 on both sides are opened, and the molten resin 7, for example, polycarbonate, is injected simultaneously and in the same amount onto both stamper surfaces (surfaces of the metal coatings 3 and 4) of the double-sided stamper 1.

After that, as shown in FIG. 3(b), the molten resin supply valve 6 is closed and both molds 8 are simultaneously clamped on each stamper surface, thereby creating a fine uneven pattern of the metal coatings 3 and 4. Duplicate optical discs.

Here, the first optical disk replicated by the metal coating 3 side is sample A1, and the first optical disc replicated by the metal coating 3 side is sample A1.
Sample 000 optical discs A B o o. Sample B0 is the first optical disc that has been duplicated on the metal coating 4 side, and sample 500 has been duplicated on the metal coating 4 side.
Sample B6° of an optical disc with 0 discs. . When stapled, these optical discs all have good signal characteristics as shown in Figure 2 (track error signal vs. radius characteristic of ID section).
is what was obtained.

Example 2 Same as Example 1, but in the stamper manufacturing process,
A Ni metal film was deposited to a thickness of 200 μm, and
i The thermosetting resin used to bond the metal coating surfaces together has a bending elastic modulus of 600 kg/-, and the injection molding machine 5
The optical disc was manufactured by duplication using polymethyl methacrylate as the molten resin used in the molding process.

Here, in this example, the first optical disk duplicated by the metal coating 3 side is sample C4, and the optical disk after 5,000 copies is sample C6. . The first optical disc duplicated by binding and the metal coating 4 side is sample D.
Sample B is a 5,000-sheet optical disc. . . When the discs were closed, good signal characteristics as shown in FIG. 3 were obtained for all of these optical discs.

Comparative Example Incidentally, a photoresist film was applied on the surface of a glass substrate, a concavo-convex fine pattern was formed on this photoresist film, a conductive film was formed on the surface of this fine pattern, and then a conductive film was formed by electroforming. A Ni metal coating was deposited to a thickness of 300 μm on the conductive coating, and the metal coating was peeled off from the glass substrate to obtain a stamper. Then, after attaching this stamper to one mold of an injection molding machine, molten polycarbonate resin is injected, and the mold is clamped with the other mold.
Copied an optical disc. Sample E is the first optical disc that has been copied using a stamper using the conventional method.
,,5000th optical disc sample E6゜. . When stapled, these optical disks all had signal characteristics that deteriorated as the number of copies increased, as shown in FIG.

Effects of the Invention As described above, according to the invention described in claim 1, two glass substrates on which metal coatings are deposited are prepared, and the metal coating sides are bonded together using a thermosetting resin. rear,
Since each glass substrate is peeled off to obtain a double-sided stamper,
It is possible to obtain a stamper with good parallelism compared to the case where a stamper is obtained by peeling a metal coating deposited on only one glass substrate from the glass substrate, and also according to claim 2
According to the invention described above, the double-sided stamper according to claim 1 with good parallelism is used, this is fixed at the center of an injection molding machine, and after injecting the same amount of molten resin to both stamper surfaces at the same time, Since each stamper surface is simultaneously clamped with the mold of the injection molding machine to duplicate the optical disk, the stamper is not deformed during molding, and the parallelism of the double-sided stamper can be maintained, making it possible to duplicate high-quality optical disks. can do.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing the manufacturing process of an optical disk according to the first embodiment of the present invention, FIG. 2 is a signal characteristic diagram of the duplicated optical disk, and FIG. FIG. 4 is a signal characteristic diagram of an optical disc reproduced according to a comparative example. 1... Double-sided stamper, 2... Thermosetting resin, 3, 4
...metal coating, 5...injection molding machine, 7...molten resin, 8...mold] Momomo°D 8hehehe-t'1'! +-Death or O.

Claims (1)

[Claims] 1. Coating a photoresist film on the surface of a glass substrate,
After forming an uneven fine pattern on this photoresist film and forming a conductive film on the surface of this fine pattern,
In a method for producing a stamper for optical disk duplication, a method for producing a stamper for optical disc duplication includes depositing and forming a metal film on the conductive film by electroforming, and peeling off the metal film from the glass substrate to obtain a stamper.
An optical disc duplication characterized in that two glass substrates on which metal coatings are precipitated are prepared, the metal coating sides are bonded together with a thermosetting resin, and then each glass substrate is peeled off to obtain a double-sided stamper. A method for manufacturing a stamper. 2. Fix the double-sided stamper in the center of the injection molding machine, inject the same amount of molten resin onto both stamper sides of the double-sided stamper at the same time, and then mold each stamper side simultaneously with the mold of the injection molding machine. A method for duplicating an optical disk, which comprises tightening the disk to duplicate the optical disk.