JP2003272253A - Manufacturing method of stamper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a stamper capable of keeping flatness of a stamper substrate high and easily manufacturing the stamper. <P>SOLUTION: The method includes: a step of coating a photo resist 103 on the surface of a stamper substrate 102; a step of fitting a support substrate 101 on the rear side of the stamper substrate 102 on which the photo resist is coated by vacuum adsorption; a step of exposing and developing the photo resist to form an information mask 107; a step of removing the part not covered by the information mask by etching to form an information pattern on the stamper substrate; and a step of removing the information mask. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stamper manufacturing method, and more particularly to a stamper manufacturing method suitable for manufacturing an optical information recording medium.

[0002]

2. Description of the Related Art In recent years, large-capacity and high-density optical information recording media have been put into practical use. In read-only media, compact discs (CDs), laser discs (LDs) and the like are widely used. C based on CD format
In a D-ROM or the like, a video CD in which an image compression technique such as MPEG is applied to record a moving image of about 1 hour on one CD.
And so on. Among them, CD-ROMs are rapidly expanding, centering on the distribution of computer and game application software.

Further, an optical disc as a next-generation multimedia is proposed which includes music data of CD, high-quality image data of LD, computer data of CD-ROM, and further integrates a read-only disc and a recording medium.
DVD (Digital Versatile Disc) in August 1996
Was standardized as. This DVD is expected as a large capacity multimedia.

FIG. 4 is a diagram showing a conventional manufacturing method of these optical disks. First, the photoresist 103 is applied to the surface of the glass substrate 201 (step a), and the photoresist 103 is irradiated with a focused beam to expose a predetermined pattern to form an exposed portion 106 (step b). Next, the glass substrate 201 is dipped in an alkali developing solution to remove the exposed portion 106, and an information mask 202 is formed (step c). Next, an electrode of a conductor is formed as a thin film on the surface of the information mask 202 by a spatch method or the like, and a metal such as Ni is deposited by plating (electroforming) to stamper 10.
9 is formed (step d). Then, the stamper 109 is used to mold the duplicate substrate 110 by injection molding or the 2P (photopolymerization) method (step e). Then, a reflective film 111 and a protective layer 11 are formed on the duplicate substrate 110.
2 is coated to complete the optical disc (step f).

In this manufacturing method, the plating step of step d takes time. In the plating process for manufacturing the stamper 109, for example, the glass master manufactured in the step c is immersed in a sulfamic acid electrolytic solution, and a Ni film is deposited on the surface of the glass master by electrolysis to form the stamper 109.
It takes 2 to 3 hours, and in some cases, more time to form a deposited film having a required thickness (about 0.3 mm) as the stamper 109, which is an obstacle to the optical disk manufacturing process. Further, stress is generated inside the stamper 109, and there are various problems such as peeling due to this stress and management of the electrolytic solution.

Further, in Japanese Patent Application Laid-Open No. 63-50937 or Japanese Patent Application Laid-Open No. 4-205936, a photoresist mask having an information pattern is formed on a metal substrate prepared in advance, and the mask is further formed. A method is disclosed in which ion milling or reactive ion etching is performed to remove a portion other than the mask by etching to form an uneven information pattern on the substrate to form a stamper.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the manufacturing method disclosed in Japanese Patent No. 937 or Japanese Patent Laid-Open No. 4-205936, it is possible to avoid problems associated with the plating process.

However, the above-mentioned Japanese Patent Laid-Open No. 63-5093
The method of manufacturing a stamper for an optical information recording medium disclosed in Japanese Patent Laid-Open Publication No. 7-27, is such that a mask of a photoresist having an information pattern is formed on a polished metal substrate and the mask is formed by ion milling or reactive ion etching. It is a method of forming a stamper by etching away parts other than the above and forming an uneven information pattern on the metal substrate.

A metal substrate having a thickness (0.3 mm) suitable for a stamper is likely to be bent or warped, and it is difficult to obtain the flatness of 20 μm required for cutting the photoresist.

On the other hand, Japanese Patent Laid-Open No. 4-205936 discloses that
It has been shown that a mirror-finished substrate (stamper substrate) produced by plating is used as a metal substrate, and the flatness is secured by adhering the substrate to a supporting substrate. However, if the substrate is attached to the supporting substrate with an adhesive, it cannot be attached to the mold of the injection molding machine. For this reason, in this publication, a further layer of plating film is bonded via a peeling layer, and peeling is performed between the first plating layer and the second plating layer. However, this method is not realistic because the process is complicated.

The present invention has been made in view of these problems, and provides a stamper manufacturing method capable of maintaining high flatness of a stamper substrate and easy to manufacture.

[0012]

The present invention adopts the following means in order to solve the above problems.

A step of applying a photoresist to the surface of the stamper substrate, a step of attaching a supporting substrate to the back surface of the stamper substrate coated with the photoresist by vacuum suction, and an exposure and development of the photoresist to form an information mask. And a step of forming an information pattern on the surface of the stamper substrate by etching away a portion not covered with the information mask, and a step of removing the information mask.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a stamper manufacturing method according to an embodiment of the present invention.

First, in step a, the stamper substrate 10
2 and prepare a photoresist 1 on the stamper substrate 102.
03 is applied.

The stamper substrate 102 may be made of a metal such as Al or an alloy containing these in addition to Ni. Further, the stamper substrate 103 can be produced by highly accurately polishing a metal plate produced by rolling or the like. Note that the stamper substrate 102 can be manufactured by electrolytic plating in a nickel sulfamate bath, but in this case, the processing requires time as described above.

The thickness required for these stamper substrates 102 is 0.1 to 0.5 mm (generally about 0.3 mm). This value of 0.3 mm is derived from the matching with the mold of the molding apparatus during injection molding and the service life associated with heat history. That is, the stamper substrate 102 is 0.1
If it is thinner than mm, it is difficult to process and it is impossible to maintain the strength that can withstand injection molding. If it is thicker than 0.5 mm, the matching between the back surface of the stamper substrate 102 and the mold becomes poor, and the heat transfer to the resin to be molded becomes uneven,
Good molding is not possible. Since the temperature of the stamper substrate changes between 70 and 200 ° C. during molding, the stamper substrate 10
If 2 is thick, cracks are likely to occur due to strain. Therefore, considering these matters, the thickness of the stamper substrate 102 is preferably about 0.3 mm.

The hardness of the stamper substrate 102 is 150.
It is preferably about 300 Hv. If it is softer than this, the life of the stamper will be shortened, and a large number of duplicate substrates cannot be manufactured. If it is harder than this, it will damage the mold.

In step b, the stamper substrate 102 is supported by the support substrate 101. As a result, the stamper substrate 102 can be prevented from bending and warping, and the flatness of the stamper substrate 102 can be secured. The flatness of the stamper substrate 102 needs to be about 20 μm or more (small in size).
This is because the movable range of the focus servo of the cutting machine for exposure is about 50 to 100 μmm. However, a stamper substrate having a thickness of about 0.3 mm cannot maintain this flatness by itself. Therefore, the stamper substrate 102 is attached to the support substrate 1
A supporting method of fixing and supporting at 01 is adopted. In this supporting method, vacuum decompression is used as a method of fixing the stamper substrate 102 to the supporting substrate 101. That is, the support substrate 101 and the stamper substrate fixed to the support substrate 101 are sealed with a transparent resin film 104, and the inside of the transparent resin film 104 is depressurized. Transparent resin film 104
Has a thickness of 0.03 mm to 0.6 mm and a flatness of 10 μm
Above, it is desirable that the unevenness in thickness is finished to about 20 μm. The material of the film is preferably polycarbonate, for example.

In step c, the photoresist 103 is exposed by irradiating a focused beam 105 such as a laser beam to form an exposed portion 106. A normal cutting machine used for exposing the photoresist 103 uses an objective lens having a very high NA for performing surface cutting. The working distance of the objective lens (distance between the objective lens and the substrate) is as short as about 0.2 to 0.3 mm. Therefore, when the transparent resin film 104 is inserted between the objective lens and the photoresist 103 exposed by the focused beam 105 as in the present embodiment, the normal cutting cannot be performed. Therefore, it is necessary to increase the working distance by increasing the focal length and the aperture while maintaining the NA of the objective lens. The objective lens must be designed according to the refractive index and thickness of the film. The wavelength of the light used for exposure depends on the resolution and the photoresist used, but light in the wavelength range of about 300 to 800 nm (for example, 457 nm for Ar ion laser or 351 nm for Kr ion laser) is used.

In step d, the stamper substrate 102 is taken out from the transparent resin film 104, and the photoresist 1
03 is developed to form the information mask 107. The development can be performed by wet development with an alkaline solution.
The wet development can be performed, for example, by immersing the stamper substrate 102 in an alkali developing solution adjusted to a predetermined concentration, or by supplying the developing solution to the surface of the photoresist 103 with a spinner. As the photoresist 103, a positive type in which an exposed portion is solubilized by development and a negative type in which an unexposed portion is solubilized by development are known, but a negative type is used in this embodiment.

In step e, a portion of the information mask 107 other than the mask (a portion of the stamper substrate surface where the mask is not formed) is subjected to, for example, dry etching to form an uneven information pattern on the stamper substrate 102 surface. Ion beam 1 is used for dry etching.
There are ion milling for physically etching at 08, reactive ion etching using a corrosive gas, etc., but an appropriate method may be selected depending on the stamper substrate, mask member, etc. used.

In step f, the stamper substrate 102
Photoresist (information mask 107) formed on
Is removed by, for example, a method of immersing it in an organic solvent or a method of ozone asher or the like. As a result, the stamper 109 is completed.

In step g, the stamper 109 produced
Using, the plastic replication substrate (replica substrate) 110 is manufactured by a method such as injection molding or photopolymerization.

In step h, the optical disk is completed by forming the reflective film 111 and the protective film 112 on the duplicate substrate 110.

FIG. 2 is a view for explaining another embodiment of the method for fixing the stamper substrate 102 to the supporting substrate 101 (corresponding to step b in FIG. 1). In the figure, 101a is a support substrate, 104a is a transparent resin film, and the support substrate 101a is integrated with the transparent resin film 104a. Therefore, the support substrate 101a can be fixed to the support substrate 101a by depressurizing the inside of the hermetic container formed of the transparent resin film 104a.

FIG. 3 is a view for explaining another embodiment of the method for fixing the stamper substrate 102 to the supporting substrate 101 (corresponding to step b and step c in FIG. 1). In the figure, 1
01b is a supporting substrate, 104b is a transparent resin film, and the supporting substrate 101b is a transparent resin film 104b.
It is integrated with. Therefore, the support substrate 101b can fix the photoresist-coated surface of the stamper substrate 102 to the support substrate 101b by depressurizing the inside of the hermetic container formed of the transparent resin film 104b.

By using a transparent substrate such as a glass substrate as the supporting substrate 101b, the focused beam 105 is irradiated through the supporting substrate 101b to allow the photoresist 103 to be irradiated.
Can be exposed.

As described above, according to this embodiment,
It is possible to efficiently provide a stamper for producing a high-quality optical information recording medium, which has good flatness, has few focus errors during cutting, and has few signal defects.

[0030]

As described above, according to the present invention, it is possible to provide a stamper manufacturing method capable of maintaining a high flatness of a stamper substrate and easily manufacturing the stamper.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a stamper manufacturing method according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating another example of a method of fixing a stamper substrate to a support substrate.

FIG. 3 is a diagram illustrating still another example of the method of fixing the stamper substrate to the supporting substrate.

FIG. 4 is a diagram illustrating a conventional optical disc manufacturing method.

[Explanation of symbols]

101 support substrate 102 stamper board 103 photoresist 104 transparent resin film 105 Focused beam 106 exposure unit 107 mask 108 ion beam 109 stamper 110 plastic substrate 111 Reflective film 112 Protective film

Claims (4)

[Claims] 1. A step of applying a photoresist to the surface of a stamper substrate, a step of attaching a support substrate to the back surface of the stamper substrate coated with the photoresist by vacuum suction, and an information mask by exposing and developing the photoresist. And a step of forming an information pattern on the surface of the stamper substrate by etching away a portion not covered with the information mask, and a step of removing the information mask. Method. 2. The step of attaching a support substrate to the back surface of the stamper substrate coated with the photoresist by vacuum suction according to claim 1, wherein the step of attaching the support substrate to the back surface of the stamper substrate coated with the photoresist is performed. And a step of accommodating the stamper substrate provided with the support substrate in a transparent film container and depressurizing the inside of the transparent film container. 3. The step of attaching a support substrate to the back surface of the stamper substrate coated with the photoresist by vacuum suction according to claim 1, wherein the back surface of the stamper substrate coated with the photoresist is integrated with a transparent film. A method of manufacturing a stamper, comprising: a step of attaching a support substrate that constitutes a vacuum container; and a step of depressurizing the inside of the vacuum container. 4. A step of applying a photoresist to the surface of a stamper substrate, a step of attaching a transparent support substrate which is integrated with a film and constitutes a vacuum container to the surface of the stamper substrate coated with the photoresist, and the vacuum container. Depressurizing the inside to attach the transparent support substrate to the stamper substrate by vacuum adsorption, exposing and developing the photoresist to form an information mask, and etching away a portion not covered by the information mask. A method of manufacturing a stamper, comprising: a step of forming an information pattern on the surface of the stamper substrate; and a step of removing the information mask.