JPH1040591A - Method for polishing backside of stamper for optical disc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for polishing the backside of a stamper without any environmental pollution which does not contaminate the surface of stamper and reduces the working time. SOLUTION: In the method of polishing the backside of a stamper by adhering in direct an adhesive film to the surface to form projection and recess for pit and/or groove of the stamper for optical disc, an adhesive film is formed of a base material film and an adhesive agent layer formed on one surface thereof, the adhesive agent layer contains a cross-lining agent of 0.1 to 30 pts.wt. having two or more cross-linking reactive group in one molecule based on the adhesive agent polymer of 100 pts.wt. having the function group which can react with the cross-linking agent, an adhesive force for the SUS304-BA plate is 10 to 180g/25mm, average thickness of the adhesive film is 20 to 300μm and fluctuation of thickness is within ±5μm of the average thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for polishing the back surface of a stamper for an optical disk. Specifically, an optical disk for recording and reproducing information using light, and a magneto-optical disk for recording, reproducing, and erasing information using light and magnetism (hereinafter, collectively referred to as an optical disk) are manufactured. The present invention relates to a method of polishing a back surface of a stamper performed at that time. More specifically, in the manufacturing process of the optical disk stamper, when polishing the back surface (the surface opposite to the surface on which the pits and / or groove irregularities are formed) of the optical disk stamper (hereinafter, these are referred to as stampers). The present invention relates to a method of directly attaching an adhesive film to a pit unevenness and / or groove unevenness forming surface (hereinafter, referred to as a signal unevenness forming surface or a stamper surface) and polishing the opposite surface (hereinafter, referred to as a back surface).

[0002]

2. Description of the Related Art An optical disk on which information is recorded, reproduced, and erased by using light or light and magnetism is used as an injection molding method, a compression molding method, an injection compression molding method, a photosensitive molding method using a stamper as a molding die. An optical disk substrate having pits and grooves formed on one side is manufactured by a method such as a reactive resin method (2P method), and a metal reflective layer, a protective layer, and the like are formed on this surface. Write-once or rewritable optical (magnetic) disks (CD
In the case of (-R, MO, etc.), a storage film made of an inorganic material such as an organic dye, a magnetic material, an alloy, or a metal oxide is formed between the substrate and the metal reflective layer, the protective layer, or the like. In general, pits refer to holes for recording signals for reproducing audio, video, information, etc., as well as address information and information for indicating the characteristics of a disc, and grooves refer to write-once and rewritable types. A guide groove for signal recording used in the case of an optical (magnetic) disk.

Usually, in a stamper manufacturing process, first, a recording master is prepared. As the master, a glass material with high surface accuracy is used. Next, a photoresist film as a photosensitive material is applied on the polished master. The photosensitive film is exposed by a laser beam to cut necessary information. When the cutting is completed, development is performed and signal irregularities are formed on the glass master. next,
After the signal concavo-convex formation surface is converted into a conductor, information is copied from a glass master as a metal (usually Ni) master by electroforming. The metal master is peeled off from the glass master, the back surface thereof is polished, the inner and outer diameters are processed, and the stamper is cut to a predetermined size. In general, in the case of the read-only type, information is copied as pits and projections, and in the case of the write-once type and rewritable type, information is copied as pits and grooves.

When an optical disk substrate is manufactured by using the stamper manufactured as described above, for example, by injection molding, injection compression molding, or the like, in the stamper manufacturing process described above, the stamper whose back surface is sufficiently polished is made of gold. Attached to the mold. At the time of injection (compression) molding, about 400 to 600
This is because the resin pressure of kg / cm ² is applied, so that the surface roughness of the back surface of the stamper and the unevenness of the thickness of the stamper appear on the stamper surface and greatly affect the characteristics of the resin substrate to be transferred. In the stamper manufacturing process, when polishing the back surface of the stamper, it is necessary to protect the signal uneven surface.

As a method of manufacturing a stamper while protecting a signal uneven surface, for example, Japanese Patent Application Laid-Open No. Sho 60-2169 discloses a method.
Japanese Patent Application Publication No. 15-205, disclose a release assisting sheet having a thickness greater than the outer diameter of a metal stamper to be polished and having a uniform thickness at the center of a disk-shaped metal plate. After attaching a double-sided pressure-sensitive adhesive sheet so as to cover and fixing a metal stamper having a signal-coated protective surface on the double-sided pressure-sensitive adhesive sheet with its signal side corresponding to the double-sided pressure-sensitive adhesive sheet, the metal stamper is polished or wrapped. A metal stamper rear surface polishing method for polishing the rear surface of the metal stamper is disclosed.

Japanese Patent Application Laid-Open No. 63-247932 discloses a process in which a protective film is provided on the surface of a stamper which has been subjected to an electroforming process, and the surface having the protective film faces the substrate to bond the stamper to the substrate. In the manufacture of the provided stamper, the stamper is 10 m in diameter from the final outer diameter.
m, wherein the stamper is provided with a portion lacking the protective film at a portion where the outer diameter of the stamper is increased, and the missing portion is used for bonding to the substrate. Is disclosed.

Heretofore, as described above, it has been practiced to protect the signal concavo-convex forming surface of the stamper with some kind of protective layer. These protective layers are formed by applying and drying a polymer solution by a spin coating method or the like.
The polymer solution for the protective layer contains an organic solvent,
Large-scale local exhaust facilities must be provided. However, it is not practical to provide a large-scale local exhaust system in a clean room, considering that a polymer protective layer is usually formed in a clean room to maintain the cleanliness of the stamper. Further, the polymer protective layer is difficult to completely remove even if washed with an organic solvent, and often remains in a trace amount, which causes contamination of the stamper.

The characteristics required for the protective layer include the uniformity of the thickness of the protective layer itself for obtaining the surface roughness of the back surface of the stamper and the uniformity of the thickness of the stamper, and the absence of defects on the surface on which the signal unevenness is formed. Cleanliness free from contamination and easy removal are required. However, in order to satisfy the characteristics required for the protective layer, advanced management is required. That is, it is necessary to filter the polymer solution with a filter, maintain the viscosity of the polymer solution in a predetermined range, and the like. Further, it is necessary to sufficiently dry the polymer protective layer, but it takes a long time to apply, dry, and cure the solution, and this is not a method that can satisfy workability. If the film shrinks during the formation of the protective layer, warping of the stamper itself becomes a problem.

[0009]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to eliminate contamination on the surface of a stamper, shorten the operation time, and eliminate environmental pollution by an organic solvent.
An object of the present invention is to provide a method of polishing the back surface of a stamper.

[0010]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that when polishing the back surface in the process of manufacturing a stamper for an optical disk, a specific pressure-sensitive adhesive film is applied to the signal uneven surface of the stamper. The present inventors have found that the above object can be achieved by directly attaching and protecting through a layer, and have reached the present invention.

That is, the present invention relates to a method for polishing an optical disc stamper by directly attaching an adhesive film to a pit and / or groove uneven surface of the optical disk stamper and polishing the back surface of the stamper. Material film and a pressure-sensitive adhesive layer formed on one surface thereof, wherein the pressure-sensitive adhesive layer has two or more crosslinks in one molecule per 100 parts by weight of a pressure-sensitive adhesive polymer having a functional group capable of reacting with a crosslinker. SU containing 0.1 to 30 parts by weight of a crosslinking agent having a reactive functional group
Adhesive strength to S304-BA plate is 10 to 180 g / 2
5 mm, and the average thickness of the adhesive film is 20
A method for polishing the back surface of a stamper for an optical disc, wherein the thickness variation is within ± 5 μm of the average thickness.

A feature of the present invention resides in that a specific adhesive film is directly adhered to the signal irregularity forming surface of the stamper when polishing the back surface in the manufacturing process of the optical disk stamper. In the pressure-sensitive adhesive film used in the present invention, since the pressure-sensitive adhesive layer contains a specific amount of a cross-linking agent, no contamination due to the pressure-sensitive adhesive remains after peeling. In addition, since the adhesive strength is limited to a specific range, the stamper firmly adheres during polishing of the back surface of the stamper, and the stamper is not deformed by peeling stress when peeling. Further, according to the present invention, there is no need to form a protective layer by spin coating a polymer solution on the signal uneven surface of the stamper. for that reason,
A solution application, a drying operation and the like for forming the protective layer can be omitted, and the operation time can be greatly reduced. Since no organic solvent gas is generated when the applied polymer solution is dried, there is no risk of polluting the environment. Therefore, according to the present invention, it is possible to improve the workability of the back surface polishing step of the optical disk stamper, prevent environmental pollution, and the like.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The optical disk stamper according to the present invention is not limited to a stamper used for manufacturing a read-only optical disk capable of reproducing information using light, such as a compact disk (CD) and a video disk (LD). It also includes a stamper used for manufacturing a write-once or rewritable optical disk, a magneto-optical disk, or the like, which can record, reproduce, and erase information using light or light and magnetism.

According to the present invention, in the backside polishing step in manufacturing a stamper, an adhesive layer is formed on one surface of a base film and, if necessary, a release film is provided on the surface of the adhesive layer. This is a stamper backside polishing method in which a specific pressure-sensitive adhesive film (peeling off a release film when pasting) is adhered to the signal uneven surface of the stamper via the surface of the pressure-sensitive adhesive layer to polish the rear surface.

First, the polishing of the back surface of the stamper for an optical disk will be described. Through a series of steps, a stamper before the back surface polishing process having signal irregularities on the surface is manufactured. The release film is peeled off from the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film, the surface of the pressure-sensitive adhesive layer is exposed, and the surface of the pressure-sensitive adhesive layer is adhered to the uneven surface of the stamper before polishing the back surface through the pressure-sensitive adhesive layer. Next, the stamper is fixed to the polishing jig board through the base film layer of the adhesive film using a vacuum device or the like, and the back surface of the stamper is polished. After the polishing, the adhesive film is peeled off. After peeling
If necessary, the signal concavo-convex formation surface may be subjected to a washing treatment such as water washing or plasma washing. Further, the adhesive film may be stored for a certain period without being peeled off.

After the polishing, the inner and outer diameters may be processed with a lathe or the like with the adhesive film adhered. The process of processing the inner and outer diameters may be performed before polishing the back surface, in which case,
An adhesive film may be adhered from the time of processing the inner and outer diameters, and after the processing, the back surface may be continuously polished with the adhesive film adhered. In the present invention, the backside polishing method is not particularly limited, and a known polishing method may be used.

Next, the pressure-sensitive adhesive film used in the present invention will be described. The pressure-sensitive adhesive film used in the present invention is a solution or emulsion containing a pressure-sensitive adhesive polymer, a cross-linking agent, and, if necessary, other additives on one surface of a base film or a release film. It is manufactured by applying and drying an adhesive coating liquid) to form an adhesive layer.

When a pressure-sensitive adhesive layer is formed on a substrate film, it is preferable to attach a release film to the surface of the pressure-sensitive adhesive layer in order to protect the film from contamination due to the environment. In the case where an adhesive layer is formed on one surface of the release film, a method of transferring the adhesive layer to a base film is employed. Which surface of the base film or release film is to be coated with the adhesive coating liquid is determined in consideration of the heat resistance of the base film and release film, and the contamination of the optical disc stamper with the signal irregularity formed surface. . For example, when the heat resistance of the release film is superior to that of the base film, an adhesive layer is provided on the surface of the release film and then transferred to the base film. When the heat resistance is the same or the base film is excellent, an adhesive layer is provided on the surface of the base film, and a release film is attached to the surface of the adhesive layer.

In consideration of the fact that the pressure-sensitive adhesive film used in the present invention is adhered to the signal uneven surface of the stamper via the surface of the pressure-sensitive adhesive layer exposed when the release film is peeled off, information from the pressure-sensitive adhesive layer is taken into consideration. In order to prevent the recording surface from being contaminated, it is preferable to use a release film having good heat resistance, apply a pressure-sensitive adhesive coating solution to the surface, and dry the surface to form a pressure-sensitive adhesive layer.

Examples of the base film of the pressure-sensitive adhesive film used in the present invention include films manufactured from synthetic resin, natural rubber, synthetic rubber, and the like. To give a concrete example,
Polyolefin, polyester, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, polybutadiene, soft vinyl chloride resin, polyamide, ionomer, and other resins, and their copolymer elastomers, and diene, nitrile, and silicone And films of synthetic rubber such as acryl based. The base film may be a single layer or a laminate.

The thickness of the base film is the sum of the thickness of the pressure-sensitive adhesive layer described later, that is, the thickness of the pressure-sensitive adhesive film is 20 to 30.
It is preferable to select the thickness to be 0 μm. A more preferred thickness of the pressure-sensitive adhesive film is 25 to 200 μm. The thickness of the pressure-sensitive adhesive film affects prevention of breakage of the stamper in the stamper back surface polishing step, workability of attaching and detaching the stamper to the signal unevenness forming surface, production cost of the pressure-sensitive adhesive film, and the like. When the thickness is reduced, the workability and the ability to protect the signal surface of the stamper tend to decrease, and when the thickness is increased, the production cost of the adhesive film tends to increase.

The base film is preferably manufactured by controlling the thickness variation so as not to affect the thickness variation of the pressure-sensitive adhesive film described later. In order to improve the adhesive strength between the substrate film and the pressure-sensitive adhesive layer, it is preferable to subject the surface of the substrate film on which the pressure-sensitive adhesive layer is provided to a corona discharge treatment or a chemical treatment. An undercoat may be used between the base film and the pressure-sensitive adhesive layer.

When peeling the release film from the adhesive film, the workability is reduced due to static electricity generated when the adhesive film is peeled from the stamper, and external contaminants adhere to the signal uneven surface of the stamper. In consideration of the fact that it becomes easier, it is preferable to perform an antistatic treatment on the surface of the base film opposite to the pressure-sensitive adhesive layer. Examples of the antistatic treatment method include a method of applying an antistatic agent such as a surfactant, a method of performing corona discharge treatment, and the like.

According to the back surface polishing method and the back surface polishing apparatus, the base film is fixed to a polishing jig board or the like on the surface opposite to the pressure-sensitive adhesive layer (for protecting the uneven surface for the stamper signal).
An adhesive layer may be provided. In this case, there is no need to provide a fixing device such as a vacuum suction device in the backside polishing apparatus. However, when the fixing pressure-sensitive adhesive layer is provided, it is preferable that the pressure-sensitive adhesive layer is provided so that the thickness variation of the entire pressure-sensitive adhesive film falls within a preferable range described later. Further, it is preferable to adjust the adhesive strength between the fixing pressure-sensitive adhesive layer and the polishing jig board so that the stamper can be peeled off after the polishing process without deforming the stamper. For example, an easy peeling process is performed on the jig board side.

Examples of the release film of the adhesive film used in the present invention include synthetic resin films such as polypropylene and polyethylene terephthalate. Preferably, the surface thereof is subjected to a silicone treatment or the like as necessary. The thickness of the release film is usually from 10 to 150 μm. Preferably it is 30 to 100 μm.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film used in the present invention is formed by applying a pressure-sensitive adhesive coating solution to one surface of a base film or a release film and drying. The pressure-sensitive adhesive coating solution is a solution containing a pressure-sensitive adhesive polymer which is a basic component thereof, and a cross-linking agent having two or more cross-linking reactive functional groups in one molecule for increasing cohesive force or adjusting adhesive force. It is an emulsion liquid. A tackifier such as a rosin-based resin or a terpene-based resin may be appropriately added to adjust the adhesive properties. When the pressure-sensitive adhesive polymer is an emulsion, a film-forming auxiliary such as diethylene glycol monoalkyl ether may be added.

Examples of the pressure-sensitive adhesive polymer constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film used in the present invention include various synthetic rubber polymers having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent. Among these, in consideration of control of adhesive properties, reproducibility, etc., alkyl acrylate polymers, alkyl methacrylate polymers, butadiene polymers, isoprene polymers, styrene-butadiene polymers and the like can be mentioned. Of these, alkyl acrylate polymers and alkyl methacrylate polymers are preferred. The liquid containing the pressure-sensitive adhesive polymer (hereinafter, pressure-sensitive adhesive main agent) may be any of a solution, an emulsion liquid, and the like.

When the adhesive polymer is an alkyl acrylate polymer or an alkyl methacrylate polymer, the main monomers constituting the adhesive polymer are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate. And alkyl acrylates such as butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate, and alkyl methacrylates. These may be used alone or as a mixture of two or more. It is preferable that the amount of the main monomer used is usually in the range of 60 to 99% by weight in the total amount of all the monomers used as the raw material of the pressure-sensitive adhesive polymer.

Examples of the comonomer having a functional group capable of reacting with a crosslinking agent, which is copolymerized with the above main monomer, include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid and monoalkyl itaconate. , Monoalkyl mesaconate, monoalkyl citraconic, monoalkyl fumarate, monoalkyl maleate, acrylic acid-
2-hydroxyethyl, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate, tert-butylaminoethyl methacrylate, and the like. One of these may be copolymerized with the above main monomer, or two or more thereof may be copolymerized. The amount of the comonomer having a functional group capable of reacting with the cross-linking agent is usually 1 to 10
Preferably, it is contained in the range of 40% by weight.

In the present invention, in addition to the main monomer constituting the pressure-sensitive adhesive polymer and the comonomer having a functional group capable of reacting with the crosslinking agent, a specific comonomer having properties as a surfactant (hereinafter referred to as polymerizable surfactant) ) May be copolymerized. The polymerizable surfactant has a property of copolymerizing with the main monomer and the comonomer, and has an action as an emulsifier when emulsion polymerization is performed. When a pressure-sensitive adhesive polymer emulsion-polymerized with a polymerizable surfactant is used, the surfactant usually does not cause contamination of the signal concavo-convex forming surface of the stamper. Further, even when slight contamination caused by the pressure-sensitive adhesive layer occurs, the signal irregularity-formed surface can be easily removed by washing with water. Examples of such a polymerizable surfactant include:
For example, polyoxyethylene nonylphenyl ether having a polymerizable 1-propenyl group introduced into the benzene ring [manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; Aqualon RN-10, R
N-20, RN-30, RN-50, etc.], and a polymerizable 1-propenyl group introduced into the benzene ring of an ammonium salt of a sulfate of polyoxyethylene nonylphenyl ether [Daiichi Kogyo Seiyaku Co., Ltd. Aquaron H
S-10, HS-20 etc.] and a sulfosuccinic acid diester having a polymerizable 2 bond in the molecule [manufactured by Kao Corporation; Latemul S-120A, S-180A etc.]
And the like.

In addition to the main monomer, a comonomer having a functional group capable of reacting with a crosslinking agent, and a polymerizable surfactant, glycidyl acrylate, glycidyl methacrylate, isocyanate ethyl acrylate, isocyanate ethyl methacrylate, (1-aziridinyl)
Monomers having a self-crosslinkable functional group such as ethyl acrylate and 2- (1-aziridinyl) ethyl methacrylate; monomers having a polymerizable double bond such as vinyl acetate, acrylonitrile, and styrene; divinylbenzene, vinyl acrylate, and methacrylic acid Polyfunctional monomers such as vinyl, allyl acrylate and allyl methacrylate may be copolymerized.

As a method for polymerizing the pressure-sensitive adhesive polymer,
Various known methods such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method can be employed, but it is preferable to consider the molecular weight of the obtained pressure-sensitive adhesive polymer and the accompanying effect on the cohesive strength of the pressure-sensitive adhesive. Among these polymerization methods, the emulsion polymerization method is preferable in consideration of obtaining a high molecular weight polymer, environmental pollution in coating and drying steps, coating properties, and the like.

As the polymerization reaction mechanism of the pressure-sensitive adhesive polymer,
Radical polymerization, anionic polymerization, cationic polymerization and the like can be mentioned, but polymerization is preferably performed by radical polymerization in consideration of the production cost of the pressure-sensitive adhesive, the influence of the functional group of the monomer, and the like. When polymerizing by a radical polymerization reaction, organic radicals such as benzoyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, di-tert-butyl peroxide, di-tert-amyl peroxide are used as radical polymerization initiators. Inorganic peroxides such as peroxide, ammonium persulfate, potassium persulfate and sodium persulfate, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-
Examples include azo compounds such as methylbutyronitrile and 4,4'-azobis-4-cyanovaleric acid.

The cross-linking agent used in the present invention is a compound having two or more cross-linking reactive functional groups in one molecule. The cross-linking reaction is carried out with the functional group of the pressure-sensitive adhesive polymer to adjust the cohesion and cohesion. Used to Examples of the crosslinking agent include epoxy compounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, and resorcin diglycidyl ether. , Tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate triadduct of trimethylolpropane, isocyanate compounds such as polyisocyanate, trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-
β-aziridinyl propionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-bis (1-aziridinecarboxamide) , N, N'-toluene-2,4-bis (1-aziridinecarboxamide), aziridine compounds such as trimethylolpropane-tri-β- (2-methylaziridine) propionate, and melamines such as hexamethoxymethylolmelamine And the like.

These may be used alone or in combination of two or more. Among the above cross-linking agents, the epoxy-based cross-linking agent has a low speed of the cross-linking reaction, and when the reaction does not proceed sufficiently, the cohesive force of the pressure-sensitive adhesive layer decreases, and depending on the state of the stamper surface, the polishing method, etc. Contamination due to layers may occur. Therefore, as appropriate, a catalyst such as an amine is added, or a monomer having an amine functional group having a catalytic action is copolymerized with an adhesive polymer, or an aziridine-based compound having an amine property when a crosslinking agent is used. It is preferable to use a crosslinking agent together.

The amount of the cross-linking agent to be added is usually within such a range that the number of functional groups in the cross-linking agent does not become larger than the number of functional groups in the pressure-sensitive adhesive polymer. However, when a new functional group is generated by the crosslinking reaction or when the crosslinking reaction is slow, an excessive amount may be added as necessary. The amount of the crosslinking agent added is preferably 0.1 to 30 parts by weight based on 100 parts by weight of the pressure-sensitive adhesive polymer.

The adhesive strength of the adhesive film affects the protection of the signal uneven surface during polishing of the back surface of the stamper, the workability of peeling from the stamper, the deformation of the stamper due to the peeling stress, and the like. From this viewpoint, the adhesive strength of the adhesive film is usually preferably from 10 to 180 g / 25 mm in terms of the adhesive strength to the SUS304-BA plate. It is more preferably 10 to 100 g / 25 mm, and still more preferably 1 to 100 g / 25 mm.
0 to 50 g / 25 mm. If the adhesive strength is too high, it is difficult to peel without deformation, and the peeling operation time is prolonged, and the stamper is deformed when the adhesive film is peeled off. Insufficiency of protection, such as intrusion between layers, affecting signal irregularities.

As a method for applying a pressure-sensitive adhesive coating solution to one surface of a substrate film or a release film, a conventionally known coating method, for example, a roll coater method, a reverse roll coater method, a gravure roll method, a bar coat method, a comma coater A coater method, a die coater method, or the like can be employed. The drying condition of the applied pressure-sensitive adhesive is not particularly limited, but generally, 8
It is preferable to dry in a temperature range of 0 to 200 ° C. for 10 seconds to 10 minutes. More preferably 80 to 170 ° C
For 15 seconds to 5 minutes. The thickness of the adhesive layer is
It is appropriately determined in consideration of the surface shape of the stamper, the protective property at the time of polishing the back surface, the adhesive strength at the time of peeling from the stamper, and the like. Usually, about 2 to 15 μm is preferable. More preferably 2-
10 μm.

In the production of the pressure-sensitive adhesive film used in the present invention, after the drying of the pressure-sensitive adhesive coating solution is completed, the pressure-sensitive adhesive film is subjected to 40 to 80 in order to sufficiently promote the cross-linking reaction between the cross-linking agent and the pressure-sensitive adhesive polymer. It may be heated at a temperature of about 5 to 300 hours. The thickness variation of the adhesive film affects the thickness variation of the stamper after the back surface polishing. Therefore, the thickness variation of the pressure-sensitive adhesive film is preferably within ± 5 μm with respect to the average value of the thickness. More preferably, it is within ± 3 μm.

The method for producing the pressure-sensitive adhesive film used in the present invention is as described above. However, from the viewpoint of preventing contamination of the signal irregularity surface of the stamper, all raw materials such as a base film, a release film, and a pressure-sensitive adhesive base material are used. Production environment, preparation, storage, application and drying environment of the adhesive coating solution is the US Federal Standard 209b
It is preferable to maintain the cleanliness of class 1,000 or less specified in the above. Also, in the method of manufacturing an optical disk of the present invention, it is preferable that the degree of cleanness be kept at a class of 1,000 or less similarly from the viewpoint of contamination of the signal uneven surface.

[0041]

The present invention will be described below in further detail with reference to examples. The present invention is not limited to these examples. The adhesive strength and thickness variation of the pressure-sensitive adhesive films obtained in Examples and Comparative Examples, the thickness variation of the obtained stamper, and surface contamination were evaluated by the following methods.

(1) Measurement of adhesive strength (g / 25 mm) Except for the conditions specified below, all were JIS Z-0237.
Measure according to Under an atmosphere of 23 ° C., a 5 × 20 cm SUS304-BA plate (JIS
G-4305) and left for 1 hour. One end of the sample was sandwiched, and a peeling angle of 180 ° and a peeling speed of 300 mm / min. Is used to measure the stress when the sample is peeled off from the surface of the SUS304-BA plate, and is converted to an adhesive force of g / 25 mm.

(2) Measurement of thickness variation of adhesive film (μm) 10c from the adhesive film obtained in Examples or Comparative Examples
A sample of m square size is taken at random. With the release film peeled off, the thickness of the pressure-sensitive adhesive film (total of the base film and the pressure-sensitive adhesive layer) is measured at a total of 100 points every 1 cm in length and width, and the average value is determined. The difference between the maximum value or the minimum value and the average value is taken, and the value (A) having the larger absolute value is regarded as the thickness variation, and is represented by ± A (μm).

(3) Measurement of Variation in Thickness of Stamper after Backside Polishing (μm) The thickness of the portion of the stamper after the backside polishing, on which signal irregularities were formed, obtained at the same time in Examples or Comparative Examples was measured. Measure 50 points at random and calculate the average value. The difference between the maximum value or the minimum value and the average value, and the value with the larger absolute value (B)
Is thickness variation and is represented by ± B (μm).

(4) Observation of contamination on the signal uneven surface of the stamper after back-surface polishing The signal uneven surface of the stamper after back-surface polishing obtained in Example or Comparative Example was observed with a microscope (× 800). And assess the status of contamination.

Example 1 In a polymerization reactor, 150 parts by weight of deionized water and 4,4′-azobis-4-cyanovaleric acid (trade name: ACVA, manufactured by Otsuka Chemical Co., Ltd.) as a polymerization initiator were used in an amount of 0. 0.5 parts by weight, 73.25 parts by weight of butyl acrylate, 14 parts by weight of methyl methacrylate, 9 parts by weight of 2-hydroxyethyl methacrylate, 2 parts by weight of methacrylic acid, 1 part by weight of acrylamide, and poly as a polymerizable surfactant Oxyethylene nonylphenyl ether (average of the number of moles of ethylene oxide added: about 20) in which a polymerizable 1-propenyl group is introduced into the benzene ring of an ammonium salt of a sulfate [Daiichi Kogyo Seiyaku Co., Ltd. Made: Aqualon HS
-20], emulsion polymerization was carried out at 70 ° C. for 9 hours with stirring using 0.75 parts by weight to obtain an acrylic resin-based water emulsion. This is neutralized with 14% by weight ammonia water,
An adhesive polymer emulsion having a solid content of about 40% by weight (adhesive base) was obtained. The obtained adhesive base emulsion 1
00 parts by weight (adhesive polymer concentration: about 40% by weight) was collected, and 14% by weight aqueous ammonia was added thereto to adjust the pH to 9.3.
Was adjusted. Next, 4 parts by weight of an aziridine-based cross-linking agent (manufactured by Nippon Shokubai Chemical Co., Ltd., Chemitite PZ-33) and 5 parts by weight of diethylene glycol monobutyl ether were added to obtain an adhesive coating solution.

The pressure-sensitive adhesive coating solution was applied to a polypropylene film (release film, thickness: 50) using a roll coater.
μm) and dried at 120 ° C. for 1 minute to form a 3 μm thick pressure-sensitive adhesive layer. Next, the treated surface of a polyethylene terephthalate film (base film) having a thickness of 38 μm subjected to corona discharge treatment was bonded and pressed to transfer the pressure-sensitive adhesive layer. After the transfer, the film was heated at 60 ° C. for 48 hours, and then cooled to room temperature to produce an adhesive film. The adhesive strength of the obtained adhesive film to the SUS-304BA plate was 30 g / 25 mm, and the thickness variation was ±
It was 2 μm.

The release film was peeled from the obtained adhesive film, and a signal of a write-once compact disc (CD-R) stamper (before polishing) having a thickness of about 0.3 mm was passed through the adhesive layer. After sticking to the surface for forming unevenness for use, the back surface of the stamper was polished. After finishing the back surface polishing, the adhesive film was peeled off. The time required for attaching and detaching the pressure-sensitive adhesive film was a short time of about 1 minute in total, and did not require a special large-sized device. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Further, when the signal concavo-convex formation surface of the stamper was observed with a microscope (× 800), no contaminants were found. The results are shown in [Table 1].

Example 2 An adhesive film was produced in the same manner as in Example 1 except that the thickness of the adhesive layer was changed to 2 μm. SUS-3 of the obtained adhesive film
The adhesive strength to the 04BA plate was 15 g / 25 mm, and the thickness variation was ± 2 μm. Using the obtained adhesive film, the back surface of a stamper for read-only compact disc (CD) (before polishing) was polished in the same manner as in Example 1. The time required for attaching and detaching the adhesive film was a short time of about 1 minute in total, and did not require a special large-sized device. About the obtained stamper, when the polishing situation was evaluated, there was no local dent,
The thickness variation of the stamper was as good as ± 2 μm or less. Also, the surface of the stamper where the signal unevenness is formed is microscope (800).
X), no contaminants were found. The results are shown in [Table 1].

Example 3 In the production of the pressure-sensitive adhesive film of Example 1, an aziridine-based crosslinking agent [Nippon Shokubai Kagaku Kogyo KK, Chemitite PZ-
No. 33] was prepared in the same manner as in Example 1 except that the addition amount was 3 parts by weight. The adhesive strength of the obtained adhesive film to the SUS-304BA plate is 45 g / 2.
5 mm, and the thickness variation was ± 2 μm. Using the obtained adhesive film, a stamper for read-only compact disc (CD) (before polishing) in the same manner as in Example 1.
Was polished. The time required for attaching and detaching the adhesive film was a short time of about 1 minute in total, and did not require a special large-sized device. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Further, when the signal concavo-convex formation surface of the stamper was observed with a microscope (× 800), no contaminants were found. The results are shown in [Table 1].

Example 4 In the production of the pressure-sensitive adhesive film of Example 1, an aziridine-based crosslinking agent [Nippon Shokubai Kagaku Kogyo KK, Chemitite PZ-
33] was added in an amount of 3 parts by weight, the thickness of the pressure-sensitive adhesive layer was 5 μm,
Polyethylene terephthalate film (base film)
A pressure-sensitive adhesive film was produced in the same manner as in Example 1 except that the thickness of the adhesive film was changed to 50 μm. SU of the obtained adhesive film
The adhesive strength to the S-304BA plate is 80 g / 25 mm,
The thickness variation was ± 3 μm. Using the obtained adhesive film, the back surface of a stamper for read-only compact disc (CD) (before polishing) was polished in the same manner as in Example 1. The time required for sticking the pressure-sensitive adhesive film was about the same as that of Example 1, but it took some time to peel off without deforming the stamper. Nevertheless, the time required for sticking and peeling was about 5 minutes in total. Also, no special large-scale equipment was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. Further, when the signal concavo-convex formation surface of the stamper was observed with a microscope (× 800), no contaminants were found. The results are shown in [Table 1].

Example 5 In the production of the pressure-sensitive adhesive film of Example 1, an aziridine-based crosslinking agent [Chemiteite PZ-, manufactured by Nippon Shokubai Chemical Co., Ltd.] was used.
33] was added at 3 parts by weight, and the thickness of the pressure-sensitive adhesive layer was 10 μm.
m, and a pressure-sensitive adhesive film was produced in the same manner as in Example 1, except that the thickness of the polyethylene terephthalate film (base film) was 50 μm. The adhesive strength of the obtained adhesive film to the SUS-304BA plate is 160 g / 25.
mm and thickness variation was ± 3 μm. Using the obtained adhesive film, the back surface of a stamper for read-only compact disc (CD) (before polishing) was polished in the same manner as in Example 1. The time required for sticking the pressure-sensitive adhesive film was about the same as that of Example 1, but it took some time to peel off without deforming the stamper. Still, paste,
And the time required for peeling was about 12 minutes in total. Also, no special large-scale equipment was required. When the polishing state of the obtained stamper was evaluated, none of the stampers had any local dents, and the thickness variation of the stamper was ±
It was good within 2 μm. Further, when the signal concavo-convex formation surface of the stamper was observed with a microscope (× 800), no contaminants were found. The results are shown in [Table 1].

Comparative Example 1 In the production of the pressure-sensitive adhesive film of Example 1, an aziridine-based crosslinking agent [Nippon Shokubai Kagaku Kogyo KK, Chemitite PZ-
33] was added at 2 parts by weight, and the thickness of the pressure-sensitive adhesive layer was 10 μm.
m, and a pressure-sensitive adhesive film was produced in the same manner as in Example 1, except that the thickness of the polyethylene terephthalate film (base film) was 50 μm. The adhesive strength of the obtained adhesive film to the SUS-304BA plate was 200 g / 25.
mm and thickness variation was ± 3 μm. Using the obtained adhesive film, the back surface of a stamper for read-only compact disc (CD) (before polishing) was polished in the same manner as in Example 1. Although there was a particular problem in sticking the adhesive film, the stamper was deformed at the time of peeling. The results are shown in [Table 1].

Comparative Example 2 In the production of the pressure-sensitive adhesive film of Example 1, the amount of butyl acrylate used was 66.25 parts by weight, the amount of methyl methacrylate used was 21 parts by weight, and an aziridine-based crosslinking agent [Nippon Shokubai Chemical Co., Ltd. Co., Ltd., the amount of Chemitite PZ-33] was 5 parts by weight, the thickness of the adhesive layer was 2 μm, and the thickness of the polyethylene terephthalate film (base film) was 50 μm. Was manufactured. The adhesive strength of the obtained adhesive film to the SUS-304BA plate is 8 g / 25 mm, and the thickness variation is ± 2 μm.
m. Example 1 was prepared using the obtained adhesive film.
The back surface of the stamper for a read-only compact disk (CD) (before polishing) was polished in the same manner as described above. The time required for attaching and detaching the adhesive film was as short as about 1 minute in total, and no special large-sized device was required. When the polishing conditions of the obtained stampers were evaluated, there were no local depressions, and the thickness variation of the stampers was as good as ± 2 μm or less. However, when the signal concavo-convex formation surface of the stamper was observed with a microscope (magnification: 800), some contamination due to infiltration of the abrasive was observed around the stamper. The results are shown in [Table 1].

Comparative Example 3 In the production of the pressure-sensitive adhesive film of Example 1, the pressure-sensitive adhesive layer had a thickness of 13 μm, the polyethylene terephthalate film had a thickness of 90 μm, and the pressure-sensitive adhesive layer and the polyethylene terephthalate film (base film). A pressure-sensitive adhesive film was produced in the same manner as in Example 1 except that the thickness variation of Example 1 was increased. SUS of the obtained adhesive film
-Adhesion to the 304BA plate is 110 g / 25 mm,
The thickness variation was ± 7 μm. Using the obtained adhesive film, the back surface of a stamper for read-only compact disc (CD) (before polishing) was polished in the same manner as in Example 1. The time required for sticking the pressure-sensitive adhesive film was about the same as that of Example 1, but it took some time to peel off without deforming the stamper. Nevertheless, the time required for sticking and peeling was about 10 minutes in total. Also, no special large-scale equipment was required.

When the obtained stamper was evaluated for polishing conditions, no local dent was found. However, the thickness variation of the stamper was ± 6 μm, which was a level that would cause problems when used in injection (compression) molding. Met. or,
Observation of the signal irregularity forming surface of the stamper with a microscope (× 800) revealed no contaminants. The results are shown in [Table 1].

Comparative Example 4 A commercially available liquid for polymer protective film (trade name, manufactured by Fine Chemical Japan Co., Ltd., trade name: Clean Coat S) was added to a write-once compact disc (CD-CD) having a thickness of about 0.3 mm.
R) stamper (before polishing) on the signal uneven surface
After spin-coating to a thickness of about 30 μm after drying and drying for about 1 hour, the back surface of the stamper was polished.
In this case, a local exhaust system for exhausting the solvent and a large-scale spin coater with strictly controlled cleanliness were required.

After the polishing was completed, the protective film was peeled off and removed. However, at the time of peeling, a part of the protective film remained on the signal irregularity forming surface, so that it was necessary to perform solvent cleaning. It took about one hour to wash the solvent. When the polishing status of the obtained stamper was evaluated, no local dent was found, and the thickness variation of the stamper was as good as ± 2 μm or less. In addition, when the signal irregularity-formed surface of the stamper was observed with a microscope (magnification: 800), several foreign substances having a size of about 3 μm were found, and further cleaning was required. The results are shown in [Table 1].

[0059]

[Table 1]

[0060]

The pressure-sensitive adhesive film used in the present invention has a moderate pressure-sensitive adhesive strength because the pressure-sensitive adhesive force is limited to a specific range, and protects the signal uneven surface during polishing of the back surface of the stamper. The stamper adheres firmly to the extent that it can be obtained, and does not deform the stamper due to peeling stress when peeling. In addition, since a specific amount of the cross-linking agent is contained, contamination due to the adhesive does not remain on the signal unevenness-formed surface after peeling. Further, according to the present invention, there is no need to form a protective layer by spin coating a polymer solution on the signal uneven surface of the stamper.
Therefore, a solution application, a drying operation, and the like for forming the protective layer can be omitted, and the operation time can be greatly reduced. Since no organic solvent gas is generated when the applied polymer solution is dried, there is no risk of polluting the environment. Therefore, according to the present invention, it is possible to improve the workability of the back surface polishing step of the optical disk stamper, prevent environmental pollution, and the like.

Continuation of front page (72) Inventor Kentaro Hirai 2-1-1 Tango-dori, Minami-ku, Nagoya-shi, Aichi Mitsui Toatsu Chemicals Co., Ltd.

Claims (7)

[Claims] 1. A method of directly affixing an adhesive film to a pit unevenness and / or groove unevenness forming surface of an optical disk stamper and polishing the back surface of the stamper, wherein the adhesive film comprises a base film and Consisting of an adhesive layer formed on one surface, the adhesive layer is based on 100 parts by weight of an adhesive polymer having a functional group capable of reacting with a crosslinking agent.
It contains 0.1 to 30 parts by weight of a cross-linking agent having two or more cross-linking reactive functional groups in one molecule, has an adhesive strength to a SUS304-BA plate of 10 to 180 g / 25 mm, and
A method for polishing the back surface of a stamper for an optical disc, wherein the adhesive film has an average thickness of 20 to 300 μm and a thickness variation is within ± 5 μm of the average thickness. 2. The method for polishing a back surface of an optical disk stamper according to claim 1, wherein the adhesive force is 10 to 100 g / 25 mm. 3. The method for polishing the back surface of an optical disk stamper according to claim 1, wherein the adhesive force is 10 to 50 g / 25 mm. 4. The method according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 2 to 15 μm. 5. The method for polishing the back surface of an optical disk stamper according to claim 1, wherein the thickness variation of the adhesive film is within ± 3 μm of the average thickness. 6. The pressure-sensitive adhesive polymer wherein a) at least one main monomer selected from the group consisting of a) alkyl acrylates and alkyl methacrylates.
% By weight, b) obtained by copolymerizing a monomer mixture containing 1 to 40% by weight of a comonomer having a functional group capable of reacting with at least one crosslinking agent selected from a hydroxyl group, a carboxyl group and an amino group. 6. The method for polishing the back surface of a stamper for an optical disk according to claim 1, wherein: 7. The cross-linking agent according to claim 1, wherein the cross-linking agent is at least one cross-linking agent selected from the group consisting of an epoxy-based cross-linking agent, an aziridine-based cross-linking agent, and an isocyanate-based cross-linking agent. Polishing method for back surface of stamper for optical disc.