JPH0630173B2 - Method for manufacturing stamper for optical disk - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for manufacturing an optical disk, and more particularly to a stamper manufacturing method.

[Background of the Invention]

In the conventional stamper manufacturing method, aluminum (Al) is vapor-deposited on a master and used as a base metal. However, the surface on which Al is vapor-deposited has surface irregularities due to the crystal grain size, and similar irregularities remain on the surface of the stamper made from this, and naturally, they also appear on the optical disk surface resulting therefrom. This unevenness has a drawback that it becomes a noise component when information is written on or read from the optical disk, and only a signal having a poor S / N ratio can be obtained.

[Object of the Invention]

An object of the present invention is to eliminate such defects and provide a method for producing a stamper having no fine irregularities.

[Outline of Invention]

In order to achieve the above object, the present invention is characterized in that a stamper is produced by using a metal having a grain size of 0.5 μm or less, for example, Ni or an amorphous metal in a patterned master.

Example of Invention

An embodiment of the present invention will be described below with reference to FIG. First, in order to make the master 3, the photoresist 2 is applied on the glass substrate 1, and the laser light modulated by the signal to be recorded is irradiated on the glass 2 for recording, and then the surface is developed to the signal. The master 3 is completed by forming a matching uneven pattern. A base metal 4 is formed on the master 3 by a method such as vapor deposition in order to prevent the photoresist pattern from swelling or deteriorating. As this metal, Ni having a small grain size or amorphous metal having no crystallinity is used to improve the flatness of the metal surface. An ultraviolet curable resin (hereinafter abbreviated as UV resin) 5 is further applied on this, and a stamper substrate 6 such as a transparent acrylic plate or glass is pressed against it, and then ultraviolet rays are irradiated to cure the UV resin 5, thereby curing the base metal 4. When it is peeled off from the boundary, the stamper 7 is completed.

Here, as a method for forming the base metal 4, there are methods such as sputtering, liquid immersion, etc., in addition to vapor deposition.

FIG. 2 (a) shows a base metal having a grain size of 0.5 μm or more, for example, A
It is a result of producing a stamper using 1 and measuring the surface with an unevenness measuring device, and it can be seen that there is unevenness of about 0.01 μm. Further, (b) is a result of similarly measuring the surface of the stamper when a metal having a particle diameter of 0.5 μm or less, for example, Ni is used, and the surface unevenness can be reduced to 0.005 μm or less. Similarly, the unevenness of the replica surface made from these stampers is 0.01μ each.
Since m and 0.005 μm or less, a replica having a good flatness of the surface can be produced as in the stamper.

Next, FIG. 3 shows the configuration of an apparatus for producing this replica. The UV resin 5-1 is applied to the stamper 7, the replica substrate 8 is brought into contact with the stamper 7, the UV resin 5-1 is uniformly spread, and then the UV light source 9 from the ultraviolet light source 9 cures the UV resin 5-1. At this time, by rotating the stamper 7, uniform hardening can be performed. After that, peel off the replica from the stamper to complete the replica. Here, since a transparent stamper substrate is used, exposure and curing can be performed from the stamper side, so a substrate such as a metal plate that does not easily transmit ultraviolet light can be used as a replica substrate.

An optical disk is completed by attaching a recording film to the replica disk thus formed. In the case of a magneto-optical disk, an amorphous alloy of a rare earth element such as GdCo and TbFe and an iron group element is known as the recording film.

In the magneto-optical disk, the direction of magnetization recorded by the rotation of the polarization plane due to the magnetization is detected, but the problem is that the reproduction signal level is low and the signal-to-noise ratio is small. Therefore, it is necessary to flatten the surface condition of the disk to reduce the noise caused by the disk surface. If the surface roughness is 0.005 μm or less, C / N (Carrier to Noise)
It has been confirmed by experiments by the inventors that the ratio becomes 50 dB (measurement bandwidth 30 KHz) or more. The optical disk manufacturing process according to the present invention has a surface roughness of 0.005μ.
m or less.

〔The invention's effect〕

As described above, according to the present invention, a stamper with a small noise component can be manufactured. Furthermore, an optical disk made based on this also has less noise components, and is effective in manufacturing an optical disk of good quality.

[Brief description of drawings]

FIG. 1 is a diagram showing the production of a stamper of the present invention, FIG. 2 is a diagram showing the results of measuring the unevenness of the stamper surface, and FIG. 3 is a configuration diagram of a replica production apparatus. 2 ... Photoresist, 4 ... Base metal, 5, 5-1 ...
… UV curing resin, 6 …… Stamper substrate, 7 …… Stamper, 8 …… Replica substrate, 9 …… UV light source.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Kaneko 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Toshio Niihara 1-280 Higashi Koigakubo, Kokubunji, Tokyo Hitachi Ltd. (72) Inventor ▲ Taka ▼ Shinji Yama 1-280, Higashi Koikekubo, Kokubunji, Tokyo Hitachi Ltd. Central Research Institute (72) Inventor Sugita 1-280, Higashi Koikeku, Kokubunji, Tokyo Hitachi, Ltd. Chuo In the laboratory (56) References JP-A-57-66547 (JP, A)

Claims (3)

[Claims] 1. A master on which information is optically recorded on a photoresist material on a predetermined substrate, a step of coating a base metal on the master, a step of applying a photocurable resin, and a step of curing the resin. A method of manufacturing a stamper for an optical disk, characterized in that a metal having a particle size of 0.5 μm or less is used as a base metal in a method of manufacturing a stamper, which comprises a step of peeling a cured resin from a master. 2. A method of manufacturing a stamper for an optical disk according to claim 1, wherein nickel is used as a base metal. 3. A method of manufacturing a stamper for an optical disk according to claim 1, wherein an amorphous metal is used as a base metal.