JP2001220692A - Method for manufacturing stamper and method for manufacturing optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a stamper and method for manufacturing optical recording medium which are capable of manufacturing the stamper and optical recording medium having uniform bit shapes and are high in yield. SOLUTION: The method for manufacturing the optical recording medium has a stage for forming an inorganic dielectric layer on one surface of a metallic substrate, a stage for forming a tight contact layer on this inorganic dielectric layer, a stage for forming a photoresist layer on this tight contact layer, a stage for exposing this photoresist layer, a stage for developing the photoresist layer with a developer, a stage for etching the metallic substrate by using the photoresist layer as a mask member and a stage for removing the tight contact layer, the inorganic dielectric layer and the photoresist layer from the metallic substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical recording medium on which audio information and video information are recorded, and a method for manufacturing a stamper.

[0002]

2. Description of the Related Art FIG. 3 is a schematic view for explaining a conventional stamper manufacturing process. In the figure, 301 is a glass master, 30
2 is an adhesion layer, 303 is a photoresist layer, 304 is an exposed portion, 305 is a resist pattern, 306 is a conductive film, 30
7 is an electroformed layer, and 308 is a stamper.

In the step shown in FIG.
Hexamethyldisilazane (hereinafter referred to as HMDS) or a silane-based coupling agent is applied on the glass master 301 to increase the adhesion between the photoresist layer 303 and a photoresist layer 303 described later. Is formed, and then a photoresist layer 303 is formed on the adhesion layer 302.

In the step shown in FIG. 3B, a glass master 301 on which a photoresist layer 303 is formed is mounted on a turntable of a cutting machine (not shown), and a laser beam modulated according to recording information is irradiated to the photoresist layer 303. Is exposed to form an exposed portion 304. FIG.
In the step shown in (c), the photoresist layer 303 is developed with a developing solution. The photoresist layer of the exposed part 304 is removed, and the resist pattern 30 is formed on the glass master 301.
5 are formed.

In the step shown in FIG. 3D, the glass master 3
01 is set in a sputtering apparatus, and a conductive film 306 of nickel, chromium, or the like is formed on the surface of the resist pattern 305 by sputtering. In the step shown in FIG. 3E, the glass master 301 on which the conductive film 306 is formed is placed on the cathode of the electroforming tank, nickel electroforming is performed, and the electroformed layer 307 is formed on the conductive film 306 of the glass master 301. Form.

In the step shown in FIG. 3F, the glass master 3
Electroformed layer 3 on which resist pattern 305 is transferred from No. 01
07 is peeled off. In the step shown in FIG.
07 is removed by oxygen ashing or the like, the electroformed layer 307 is processed into a desired shape, and the back surface of the electroformed layer 307 is mirror-polished to obtain a stamper 308. The replica substrate is obtained by attaching the stamper 308 to the mold of the injection molding machine and molding the resin substrate.

One of the requirements for the optical recording medium manufacturing process is to reduce the time required for the optical recording medium manufacturing process. At present, the bottleneck for speeding up the optical recording medium manufacturing process is the electroforming process in the stamper manufacturing process shown in FIG. Generally, in the manufacturing process of the compact disc, the electroforming step is performed for about 4 hours to about 6 hours.
Time is spent on time.

In order to solve the above problems, Japanese Patent Application Laid-Open Nos. 3-150738 and 5-62254 disclose an optical recording medium manufacturing process which does not include an electroforming process. FIG. 4 is a schematic diagram for explaining a stamper manufacturing process in a conventional optical disc manufacturing process that does not include an electroforming process. In the figure, 401 is a substrate, 402 is a photoresist layer, 403 is an exposed part, 404 is a resist pattern, 40
5 is a pit and 406 is a stamper.

In the step shown in FIG. 4A, a photoresist layer 402 is formed on a substrate 401 made of a metal such as nickel. The HMDS and the silane coupling agent used in the manufacturing process of FIG. 3 are for increasing the adhesion between the glass master and the photoresist layer, and do not have the effect of increasing the adhesion between the metal substrate and the photoresist layer. Do not use.

In the step shown in FIG. 4B, the substrate 401 on which the photoresist layer 402 is formed is mounted on a turntable of a cutting machine (not shown), and the photoresist layer 40 is irradiated with a laser beam modulated in accordance with recording information.
2 is exposed to form an exposed portion 403. In the step shown in FIG. 4C, the photoresist layer 402 is developed with a developing solution. The photoresist layer of the exposed part 403 is removed,
A resist pattern 404 is formed on the substrate 401.

In the steps shown in FIGS. 4D and 4E, an etching process is performed using the resist pattern 404 formed on the substrate 401 as a mask member. When the pit 405 having a predetermined depth is obtained on the substrate 401, the etching process ends. While the electroforming process shown in FIG. 3E takes about 4 to 6 hours, the etching process in this process takes 20 to 20 hours.
It takes 40 minutes to 40 minutes.

In the step shown in FIG. 4F, the resist pattern 404 attached to the substrate 401 is removed by oxygen ashing or the like, and the stamper 406 is obtained by processing the substrate 401 into a desired shape.

In the manufacturing process shown in FIG. 4, unlike the stamper 308 in the manufacturing process shown in FIG. 3, the pits of the stamper 406 are concave pits. Therefore, stamper 3
In order to obtain the same convex pits as in 08, a negative type photoresist is used as the photoresist layer 402, or when irradiating the photoresist layer 402 with laser light, a portion to be a pit is not irradiated with laser light. Then, a portion to be a land is irradiated with a laser beam.

[0014]

Generally, a photoresist used in the production of an optical recording medium is, for example, a positive-type photoresist, which comprises a naphthoquinone azide-based photosensitive agent and a novolak resin as a base resin. . The novolak resin is soluble in an alkaline aqueous solution of a developer, but becomes insoluble in a developer when mixed with a naphthoquinone azide-based photosensitizer. Therefore, the photoresist layer before being exposed is insoluble in the developing solution.

When the photoresist layer is irradiated with laser light, the naphthoquinone diad-based photosensitizer decomposes and changes to alkali-soluble indene carboxylic acid, so that the exposed portion of the photoresist layer becomes soluble in a developing solution. Become. In the case of a negative photoresist, although the plasticity is different, an alkaline aqueous solution is used as a developing solution.

Therefore, in the manufacturing process shown in FIG. 4, when a photoresist and a developing solution used for manufacturing a conventional optical recording medium are used, the substrate 401 made of a metal such as nickel is eroded by an aqueous alkaline solution, Substrate 401
There is a problem that the surface in contact with the developer becomes rough. Since the surface of the substrate 401 which is in contact with the developing solution is a portion to be etched by the etching process, the surface roughness is reflected on the shape of the bottom surface of the pit, and the phenomenon that the etching does not progress uniformly occurs and the pit shape is generated. Was sometimes disturbed.

In the step shown in FIG. 4A, after a photoresist is applied to the substrate 401, the substrate 401 is baked at 70 to 100 ° C. in order to evaporate a solvent contained in the photoresist layer 402. Perform processing. Since the substrate 401 made of a metal such as nickel has a higher thermal conductivity than the glass master, heat stored in the substrate 401 heated by the baking process is transmitted to the photoresist layer 402 more than when the glass master is used. . For this reason, the cross-linking structure of the portion of the photoresist layer 402 close to the substrate 401 changes, so that the exposure sensitivity is reduced and the pit shape may be disturbed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a stamper manufacturing method for manufacturing a stamper by etching a metal substrate such as nickel and an optical recording medium using the stamper. An object of the present invention is to provide a stamper manufacturing method and an optical recording medium manufacturing method capable of manufacturing a stamper and an optical recording medium having a uniform pit shape and having a high yield.

[0019]

According to a first aspect of the present invention, there is provided a stamper manufacturing method, comprising the steps of: forming an inorganic dielectric layer on one surface of a metal substrate; A step of forming an adhesion layer on the inorganic dielectric layer to increase the adhesion between the substrate and the photoresist layer, a step of forming a photoresist layer on the adhesion layer, and forming the photoresist layer on the basis of recorded information. Exposing, developing the exposed photoresist layer with a developing solution, etching the metal substrate with the developed photoresist layer as a mask member, and contacting the etched metal substrate with the metal substrate. Removing the layer, the inorganic dielectric film and the photoresist layer.

The invention according to claim 2 of the present application provides a stamper manufacturing step of manufacturing a stamper in which recording information is recorded as an uneven pit array, and a step of manufacturing a replica substrate in which the pit array is transferred from the stamper. Forming a reflective film on the surface of the replica substrate on which the pit rows are transferred, wherein the stamper forming step includes forming an inorganic dielectric layer on one surface of the metal substrate. And a step of forming an adhesion layer on the inorganic dielectric layer to increase the adhesion between the substrate and the photoresist layer, a step of forming a photoresist layer on the adhesion layer, Exposing according to recorded information, developing the exposed photoresist layer with a developing solution, and using the developed photoresist layer as a mask member to form the gold layer. Etching the substrate, the adhesive layer from the metal substrate has been etched, and further comprising a step of removing the inorganic dielectric film and the photoresist layer.

[0021]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a view for explaining an embodiment of a manufacturing process using the optical recording medium manufacturing method of the present invention. FIG. 2 is a view for explaining an embodiment of a cutting step and a stamper manufacturing step of a manufacturing step using the optical recording medium manufacturing method of the present invention. In the figure, 201 is a nickel substrate, 202 is an inorganic dielectric layer, 203 is an adhesion layer, 2
04 is a photoresist layer, 205 is an exposure part, 206 is a resist pattern, 207 is a pit, and 208 is a stamper.

First, FIG. 1A shows a premastering step. In this step, information such as a lead-in, a lead-out, an index and an address is added to music data recorded in a studio or the like and recorded on an optical disk, a master tape, or the like.

The cutting process shown in FIG.
The stamper manufacturing process (c) will be specifically described with reference to FIG. In the step shown in FIG. 2A, one side is mirror-polished to a flatness of about 20 μm and the thickness is about 0.3 mm.
Is mounted on a sputtering apparatus. Since the nickel substrate 201 is used as a stamper in an injection molding process to be described later, it has a thickness of about 0.3 mm in consideration of matching with a mold of a molding apparatus and molding characteristics. If the nickel substrate 201 is thicker than about 0.3 mm, the matching with the mold becomes poor, so that the way of transmitting heat to the resin to be molded becomes uneven, and the pit cannot be molded in a uniform shape. During the injection molding, the nickel substrate 20
Since the temperature of No. 1 changes in the range of 70 to 200 ° C., cracks due to distortion are likely to occur when the substrate thickness is large. If the thickness of the nickel substrate 201 is less than about 0.3 mm, mechanical strength cannot be maintained. As the substrate material, metals or alloys such as copper and aluminum can be used in addition to nickel. If nickel used as a stamper of a conventional optical recording medium is used as a substrate material, injection molding can be performed under the same injection molding conditions in a conventional optical recording medium manufacturing process.

SiO2 film, Si by sputtering
An inorganic dielectric layer 202 made of a silicon-based inorganic dielectric material such as an O film or a SiN film is formed on the mirror-polished surface of the nickel substrate 201. The thickness of the inorganic dielectric layer 202 is preferably about 10 to 50 nm in consideration of the effect of preventing the infiltration of the developer described below and the film formation time.

Here, the reason for using a silicon-based inorganic dielectric material for the inorganic dielectric layer 202 is that the inorganic dielectric layer 202 has an adhesive property with the HMDS or silane-based coupling agent used in the conventional stamper manufacturing process shown in FIG. The reason is that the photoresist layer can be prevented from peeling from the nickel substrate 201, which will be described later.

In the step shown in FIG. 2B, an HMD is formed on the surface of the nickel substrate 201 on which the inorganic dielectric layer 202 is formed.
A monomolecular film of S or a silane coupling agent is applied to the adhesion layer 20.
3 is formed by a spin coating method.

In the step shown in FIG. 2C, a photoresist layer 204 is formed on the adhesion layer 203 formed on the nickel substrate 201 by spin coating. The thickness of the photoresist layer 204 is determined by etching conditions (etching rates of the photoresist layer 204 and the nickel substrate 201 and pit depths formed by the etching process) described later.

As the photoresist layer 204, a positive photoresist or a negative photoresist may be used. When a positive photoresist is used, the resulting stamper has irregularities that are opposite to those of the conventional stamper. Therefore, when irradiating the photoresist layer 204 with laser light, the laser light is not applied to a portion to be a pit, A portion to be a land is irradiated with a laser beam. When a negative photoresist is used, the resulting stamper has the same irregularities as a conventional stamper.

The nickel substrate 201 on which the photoresist layer 204 is formed is placed in a clean oven at 90
Prebaking is performed for 30 minutes at a temperature of ° C. to remove the solvent remaining in the photoresist layer 204. In this embodiment, since the inorganic dielectric layer 202 having a low thermal conductivity is formed between the nickel substrate 201 and the photoresist layer 204, the heat stored in the nickel substrate 201 heated by the baking process is applied. Photoresist layer 204
Thus, the cross-linking structure and the like of the portion near the nickel substrate 201 do not change, and the exposure sensitivity does not decrease.

In the step shown in FIG. 2D, the nickel substrate 201 on which the photoresist layer 201 has been formed is mounted on a turntable of a cutting machine (not shown) and irradiated with a laser beam modulated in accordance with recording information. Is exposed. When a negative type photoresist is used as the photoresist layer 204, the exposed nickel substrate 201 is placed in a clean oven, and reverse baking is performed at a temperature of 110 ° C. for 10 minutes. 205 is made alkali-insoluble. Further, i-line exposure is performed on the photoresist layer 204 to make the unexposed portions other than the exposed portions 205 alkali-soluble. As described above, the steps from FIG. 2A to FIG.
This corresponds to the cutting step (b).

In the step shown in FIG. 2E, the nickel substrate 201 is attached to a developing device, and spin development is performed using an organic alkali developer to develop the photoresist layer 204. Thereafter, the application of the organic alkali developer is stopped, and spin drying is performed. The photoresist layer 204 is developed, and a resist pattern 206 is formed on the nickel substrate 201. In this embodiment, since the inorganic dielectric layer 202 insoluble in the organic alkali developing solution is formed between the nickel substrate 201 and the photoresist layer 204, the surface of the nickel substrate 201 is roughened by the organic alkali developing solution. Never be.

In the steps shown in FIGS. 2F and 2G, the resist pattern 20 formed on the nickel substrate 201 is formed.
An etching process (reactive ion etching or ion milling) is performed using 6 as a mask member. Nickel substrate 2
When the pit 207 having a predetermined depth is obtained at 01, the etching process is terminated. In this embodiment, since the inorganic dielectric layer 202 that is insoluble in the organic alkali developer is formed,
Etching can proceed uniformly, and pits having good shapes can be formed by etching.

In the step shown in FIG. 2H, the resist pattern 206 adhering to the nickel
3 and the inorganic dielectric layer 202 are removed by acetone cleaning, oxygen ashing, or the like, and the nickel substrate 201 is processed into a desired shape to obtain a stamper 208. that's all,
2E to 2H correspond to the stamper manufacturing process in FIG. 1C.

Next, in the injection molding step shown in FIG. 1D, the stamper 208 is attached to a mold of an injection molding machine, and a resin such as polycarbonate is molded to obtain a replica substrate. In the step of forming the reflective film and the protective film shown in FIG. 1E, the replica substrate is attached to a sputtering apparatus, and a reflective film of aluminum, gold, or the like is formed on the surface of the replica substrate on which the pits are transferred by 50 to 100 nm by a sputtering method.
Formed to a thickness of The replica substrate on which the reflective film is formed is mounted on a spin coater, and a protective film such as an ultraviolet curable resin is formed on the reflective film by spin coating.

[0035]

According to the present invention, a uniform stamper manufacturing method for manufacturing a stamper by etching a metal substrate such as nickel, and an optical recording medium manufacturing method for manufacturing an optical recording medium using the stamper are provided. A stamper and an optical recording medium having a pit shape can be manufactured, and a stamper manufacturing method and an optical recording medium manufacturing method with high yield can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of a manufacturing process using an optical recording medium manufacturing method according to the present invention.

FIG. 2 is a schematic diagram illustrating an embodiment of a cutting step and a stamper manufacturing step of a manufacturing process using the optical recording medium manufacturing method of the present invention.

FIG. 3 is a schematic view for explaining a conventional stamper manufacturing process.

FIG. 4 is a schematic view for explaining a stamper manufacturing process in a conventional optical disc manufacturing process that does not include an electroforming process.

[Explanation of symbols]

 201 Nickel Substrate 202 Inorganic Dielectric Layer 203 Adhesion Layer 204 Photoresist Layer 205 Exposure Section 206 Resist Pattern 207 Pit 208 Stamper 301 Glass Master 302 Adhesion Layer 303 Photoresist Layer 304 Exposure Section 305 Resist Pattern 306 Conductive Film 307 Electroforming Layer 308 Stamper 401 substrate 402 photoresist layer 403 exposed part 404 resist pattern 405 pit 406 stamper

Claims (2)

[Claims] A step of forming an inorganic dielectric layer on one surface of a metal substrate; a step of forming an adhesion layer on the inorganic dielectric layer to increase the adhesion between the substrate and a photoresist layer; Forming a photoresist layer on the adhesive layer, exposing the photoresist layer according to recorded information, developing the exposed photoresist layer with a developer, developing the photoresist A step of etching the metal substrate using a layer as a mask member, and a step of removing the adhesion layer, the inorganic dielectric layer, and the photoresist layer from the etched metal substrate. Method. 2. A stamper manufacturing step of manufacturing a stamper in which recording information is recorded as a pit array having irregularities; a step of manufacturing a replica substrate on which the pit array is transferred from the stamper; An optical recording medium manufacturing method comprising: a step of forming a reflective film on the transferred surface; wherein the stamper forming step includes: forming an inorganic dielectric layer on one surface of a metal substrate; A step of forming an adhesion layer on the layer to increase the adhesion between the substrate and the photoresist layer; a step of forming a photoresist layer on the adhesion layer; and a step of exposing the photoresist layer according to recorded information. Developing the exposed photoresist layer with a developer; and etching the metal substrate using the developed photoresist layer as a mask member. Degree and, the adhesion layer from the metal substrate has been etched, the inorganic dielectric film and the optical recording medium manufacturing method characterized by comprising the step of removing the photoresist layer.