JPH0628720A - Method for manufacturing stamper for optical recording medium - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a high performance and highly reliable optical recording medium. [Structure] A positive resist layer 2 is formed on a master 1 and exposed and developed in a predetermined pattern of an optical recording medium,
In a stamper for an optical recording medium, which is formed by converting the surface of the metal film 3 into a conductor and further electroforming the metal layer 4 and peeling the metal layer 4 from the master 1, the surface is treated with an organic solvent or an alkaline solution before exposing the resist layer 1. Apply processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the recording of information using light,
The present invention relates to a method for manufacturing a stamper for an optical recording medium used for an optical recording medium for reproducing or erasing.

[0002]

2. Description of the Related Art A conventional stamper for an optical recording medium is prepared by first applying a positive resist on a glass master and exposing it with a laser beam and then developing the resist with an alkaline solution. The portion is made into a conductor by vacuum-depositing nickel, and the portion made into a conductor is used as an electrode to electroform nickel and peel it from the glass master to form a stamper. An optical recording medium is produced by molding a substrate using the stamper and forming a recording layer on the substrate. As described above, conventionally, after the resist is applied, prebaking is performed at a temperature of about 50 ° C. to 90 ° C., and exposure is performed with the laser beam focused as it is.

[0003]

However, in the conventional technique, after the resist is applied, prebaking is performed at a temperature of about 50 ° C. to 90 ° C. and exposure is performed by the laser beam focused as it is. It is easily dissolved by the developing solution, accurate grooves and pits depending on exposure are not formed, and the resist layer is likely to have rounded corners, and the surface unevenness is large, and the noise of the optical recording medium created using this Had the problem of becoming an increasing factor of

Therefore, the present invention is intended to solve such a problem, and its purpose is to make it difficult for the surface of a resist to be dissolved by a developing solution and to form an accurate groove or pit according to exposure. It is an object of the present invention to provide a high-performance and high-reliability optical recording medium in which the resist layer has a shape with no corners and the surface irregularities are reduced to reduce the noise of the optical recording medium produced using the same.

[0005]

The method of manufacturing an optical recording medium of the present invention comprises forming a positive resist layer on a master,
In a stamper for an optical recording medium, which is created by exposing and developing a predetermined pattern of an optical recording medium, making the surface conductive with a metal film, and further electroforming the metal layer and peeling it from the master.
Before the resist layer is exposed, surface treatment is performed with a substance that reduces the reactivity of the surface of the resist.

[0006]

The present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual diagram of a method for manufacturing a stamper for an optical recording medium of the present invention. Reference numeral 1 is a glass master, 2 is a positive resist layer, 3 is a surface-treated portion, 4 is an exposed portion, 5 is a developed portion, 6 is a metal film, 7 is a metal layer, and 8 is a completed stamper for an optical recording medium. Is.

The surface of the glass master 1 is cleaned, and hexamethyldisilazane improves adhesion to the resist.
Next, a positive type resist layer 2 is formed by applying by a spin coating method, and a solvent in the resist layer is removed by performing prebaking at about 50 ° C to 90 ° C.

Next, the surface of the resist layer is modified with an organic solvent to form the surface-treated portion 3. The surface modification is a method in which the organic solvent is spread on the resist while rotating the entire glass master, and the surface modification is performed by spin coating. As the type of solvent, aromatic organic solvents such as toluene, xylene, and chlorobenzene, as well as low-polarity solvents such as dioxane and glycerin are preferable. Further, surface modification with ammonia or an organic alkali of amines may be used in addition to a dilute solution of inorganic alkali such as sodium hydroxide or potassium hydroxide. Further, it is possible to use an aqueous solution containing about several hundred ppm of anions, cations, amphoteric or neutral surfactants and the like.

After that, the solvent used for the surface modification is dried and exposed according to the pattern of the optical recording medium to form the exposed portion 4. The exposure is carried out by using a HeCd laser focused while rotating the master 1. Then, it is developed with an inorganic or organic alkaline developer to form a developed portion 5. Then, post baking is performed at about 80 to 90 ° C.

Next, a nickel film is formed by vacuum deposition to 40
A metal film 6 is formed by forming a metal film 6 as an electrode, and a nickel layer which is a metal layer 7 is formed into a metal film 6.
Electroform about 2 to 0.3 mm. Then, the stamper 8 is formed by peeling from the glass master 1 and processing the inner and outer diameters.

Next, using this stamper 8, a substrate is molded using a polycarbonate resin or an amorphous polyolefin by injection molding, injection compression molding, a photopolymer method or the like.

Further, a recording layer is formed on this substrate to form an optical disc. In this case, as the recording layer, various ones such as a magneto-optical recording film made of an alloy of a rare earth metal and a transition metal, an optical phase change type mixture of tellurium and tellurium oxide, or one using a dye such as cyanine can be used. It is possible.

Next, the resist used in this embodiment will be described. As the positive resist layer 2, naphthoquinone diazide and phenol novolac resin are mainly used with cellosolve acetate as the main solvent, but the solvent is not limited to this and xylene, butyl acetate, 2-ethoxyethyl acetate, etc. May be used. It is preferable that the light used for exposure has high sensitivity. That is, He
A Cd laser with high sensitivity is used. In order to improve the resolution of the resist, the dispersion of the molecular weight of the phenol-novolak resin (weight average molecular weight / number average molecular weight) is 3
It is preferable to use a compound synthesized so that the amount becomes less than 1. More preferably, it is less than 2. The development is carried out with an alkaline solution, but sodium silicate type, sodium phosphate type or buffers thereof or quaternary alkyl ammonium hydroxide can be used.

Further, it is preferable to add a surfactant to this developing solution in order to obtain uniform development. The surfactant to be added has less inhibitory effect on development, and an anionic surfactant having good compatibility with the alkali of the developing solution is preferable. Among the anionic surfactants, the compatibility and stability with the developing solution are taken into consideration. A polymer having a relatively large molecular weight and high permeability and stability is preferable. Examples include alkyl sulfocarboxylates, α
-Olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof,
N-acyl methyl taurine salt, alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol phosphate ester, alkyl Examples thereof include phosphoric acid esters and alkylallyl sulfonates.

Next, a case where an optical recording medium is manufactured by using the stamper for optical recording medium manufactured by the method according to the present invention will be described.

First, as shown in this embodiment, exposure is performed using a laser cutting machine so that the track pitch and the pit pitch are halved as compared with the conventional case. In the past, the track pitch was 1.6 μm, so this is set to 0.8 μm. Similarly, the pit rows are also halved. Then, development is performed to manufacture a substrate by the method shown in this embodiment. With that substrate,
Using an optical disk having a multilayer film made of platinum and cobalt as a recording layer, recording and reproducing was performed by an optical system in which a laser having a wavelength of 830 nanometers was set to a wavelength of 415 nanometers by an SHG element. It was possible to reduce noise with the optical recording medium prepared. Further, this noise reduction was possible even when using a rare earth transition metal-based recording film which is mainly used at present. In this case, the track pitch was 1.6 μm. Further, when the stamper for optical recording medium prepared by the conventional method and the stamper for optical recording medium prepared by the method of the present invention were observed by an atomic force microscope, the stamper for optical recording medium of the present invention was obtained by the conventional method. It was observed that the surface irregularities were reduced.

It should be noted that the present invention should not be considered to be limited to only these examples, and various modifications can be made in each section of the present examples without departing from the gist of the present invention.

[0018]

As described above, according to the present invention, a stamper for an optical recording medium having an improved surface property is formed, so that the surface of the substrate for an optical recording medium produced by using the stamper is formed. Has the effect of improving the performance and reducing the substrate noise, thereby improving the performance and reliability of the optical recording medium.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a method for manufacturing a stamper for an optical recording medium of the present invention.

[Explanation of symbols]

 1 glass master 2 positive resist layer 3 surface treated part 4 exposed part 5 developed part 6 metal film 7 metal layer 8 stamper for optical recording medium

Claims (2)

[Claims] 1. A positive type resist layer is formed on a master plate, exposed and developed in a predetermined pattern of an optical recording medium,
In a stamper for an optical recording medium, which is formed by making a surface a conductor with a metal film and further electroforming the metal layer and peeling it from the master, a substance that lowers the reactivity of the surface of the resist before exposing the resist layer. A method for manufacturing a stamper for an optical recording medium, characterized in that the surface treatment is performed by the method. 2. As the substance that reduces the reactivity of the surface of the resist, an aromatic organic solvent, a solvent having a low polarity, a dilute solution of an inorganic alkali such as sodium hydroxide or potassium hydroxide, an organic alkali, an anion, a cation, 2. The method for producing a stamper for an optical recording medium according to claim 1, wherein the aqueous solution contains an amphoteric or neutral surfactant and the like in an amount of several hundred ppm.