KR20080069894A - Photo-curable composition having inherently excellent releasing property and pattern transfer property, method for transfering pattern using the same and light recordimg medium having polymer pattern layer produced using the same - Google Patents

Abstract

A radiation curing composition, a method for transferring a pattern by using the composition, and an optical recording medium using the composition are provided to improve transfer property and releasing property. A radiation curing composition comprises 100 parts by weight of a urethane-polydimethylsiloxane copolymeric prepolymer prepared by the reaction of a polyol having at least two hydroxyl groups at a molecule, a reactive polydimethylsiloxane having at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxyl group, a halogen atom, a thiol group and a (meth)acrylate group at the side chain or terminal of polydimethylsiloxane, and an aliphatic or aromatic polyisocyanate compound; 10-80 parts by weight of a mono- to tetravalent (meth)acrylate monomer; and 0.1-10 parts by weight of a photoinitiator.

Description

Photo-curable composition having inherently excellent release property and pattern transfer property, pattern transfer method using same, and optical recording medium having polymer pattern layer formed using same transfering pattern using the same and light recordimg medium having polymer pattern layer produced using the same}

The present invention relates to a photocurable composition, a pattern transfer method using the same, and an optical recording medium having a polymer pattern layer produced using the same, and more particularly, a photocurable composition having excellent releasability and pattern transfer property, using the same. A pattern transfer method and an optical recording medium having a polymer pattern layer formed using the same.

In the manufacturing process of optical recording media such as compact disks, digital versatile disks (DVD) or magnetic disks and magnetic recording media, semiconductor devices, display devices, ultra-fine electrical and electronic devices, it is necessary to form fine patterns on the substrate. Traditionally, the fine pattern is formed by a photolithography method including a light irradiation process through a photomask, a developing process and an etching process. That is, a photoresist made of photosensitive polymer material is coated on a substrate, and the photoresist is exposed to light of a predetermined wavelength through a photomask having a predetermined pattern to form a potential photoresist pattern. The latent image pattern is developed to form a photoresist pattern on the substrate, and the substrate is etched using this as an etching mask to transfer the pattern of the photomask onto the substrate.

By the way, in the photolithography method, the circuit line width (pattern line width) is governed by the wavelength of light used in the exposure process. In view of the current state of the art, it is very difficult to form an ultrafine pattern, for example, an ultrafine pattern having a line width of 100 nm or less, on a substrate using a photolithography process. In addition, in the photolithography method, since the photoresist coating, exposure, development, etching, cleaning, and the like have to go through several steps, the process is complicated, requires a lot of processing time, and requires various kinds of expensive equipment. Due to this problem, the photolithography method has disadvantages of high cost and low productivity.

Non-traditional lithographic methods have been proposed as techniques for overcoming the limitations of the photolithography method described above. One of them is the nano-imprint lithography method.

Nanoimprint lithography is an extension of the conventional press process to the nano-area. In this technique, a three-dimensional pattern is formed on a substrate by pressing a mold having a predetermined three-dimensional pattern on a nano scale and formed of a hard material such as silicon (Si), silicon dioxide, or quartz on the substrate. Repeated transfers. Specifically, the mold is a technique in which a mold is opposed to a substrate coated with a thermoplastic polymer material and then pressed to transfer a three-dimensional nanoscale pattern of the mold to the thermoplastic polymer material on the substrate. The pattern of the mold may then be transferred onto the substrate by etching the underlying substrate or depositing another material on the pattern using the transferred thermoplastic polymer material pattern as an etch mask.

Nano implant lithography techniques can be broadly classified into thermal nano imprint method, photo nano imprint method, and micro contact printing (uCP). The thermal nanoimprint method is a method of transferring a pattern of a mold by coating a thermoplastic polymer resin on a substrate, heating the substrate above the glass transition temperature of the polymer, and pressing the mold onto the polymer coating. The photo nanoimprint method is a method of transferring a pattern of a mold by coating a photocurable composition on a substrate, pressing a mold on the coating, and irradiating light of a specific wavelength such as ultraviolet light to cure the monomer. In this method, the mold is made of a transparent material through which light such as ultraviolet rays such as quartz and glass can pass. Microcontact printing is the most representative method of the soft lithography process. In this method, ink is applied to the surface of the protrusion of the micropattern of a mold made of a silicone-based elastomer having a low surface tension such as polydimethylsiloxane (PDMS), and then the mold is pressed onto the substrate to press the micropattern onto the substrate. It's a way to transcribe.

Nano implant lithography has the following advantages:

1) Since it is basically a press technology, the process can be made simple and very inexpensive.

2) Because of the use of rigid molds such as silicon and silicon dioxide, it is possible to efficiently and repeatedly transfer ultra fine patterns over large areas.

3) Since the limit resolution of the transfer pattern is determined according to the pattern shape of the mold, it is possible to easily and repeatedly transfer the three-dimensional fine patterns of 5 nm level in a batch.

However, the nanoimprint lithography technique has a problem that it is not easy to separate the mold from the substrate without damaging the polymer pattern layer formed on the substrate after the press for pattern transfer. That is, when the mold is separated from the substrate, a phenomenon in which the micropattern transferred to the substrate is damaged due to the adhesion between the mold and the polymer pattern layer is detached and attached to the mold.

In this way, if the mold release property between the mold and the polymer pattern layer on the substrate is poor, not only the damage of the transferred polymer pattern layer due to the adhesion phenomenon, the mold is contaminated and the mold cannot be used repeatedly. Therefore, improving mold release properties is one of the important challenges to be solved in nanoimprint lithography techniques.

In order to improve the problem of adhesion between the mold and the polymer pattern layer, there are the following nanoimprint lithography techniques disclosed in the prior art.

Republic of Korea Patent No. 0568581 (1) active energy ray-curable urethane oligomers; (2) a (meth) acrylate-based, vinylether or arylether-based monomer having a reactivity with the urethane-based oligomer, or a mixture thereof; (3) reactive or non-reactive compounds having a silicone group or a fluorine group, or both; And (4) discloses a composition for a micropattern forming mold comprising a photoinitiator. However, according to the tests of the inventors, the photocurable resin composition prepared according to this patent is insufficient in releasability and cannot be used for nanoimprint lithography operation using a mold having a pattern depth of 100 nm or less. Specifically, when nanoimprint lithography is performed using the above-described mold of the photocurable resin composition, when the mold is separated after photocuring, the surface of the mold is contaminated with polymer debris and the transferred pattern is also collapsed in several places. .

In addition, in the nanoimprint lithography technique, a technique of coating a fluorine-based or silicone-based oil on the surface of the mold in order to improve the mold release property by reducing the surface tension of the mold surface to reduce the adhesive force is known to those skilled in the art.

For example, Korean Patent Laid-Open Publication No. 2005-0071230 forms a self-assembled monolayer (SAM) as a release coating film on the surface of a mold for forming a microstructure by using a release agent mixed with a surfactant and an organic solvent. Disclosed is a mold for molding a microstructure having improved release property.

In the method using such a release agent coating, the release agent layer should have a thickness of several nanometers or less because it should not affect the pattern shape of the nanosize. However, forming a separate release agent layer to satisfy these conditions before forming the polymer layer has a problem of reducing productivity and raising the manufacturing cost. In addition, if the physicochemical properties of the release agent used therein are unstable, it may act as a source of contamination of the mold and / or substrate. In addition, the photocurable composition of the prior art used to form the polymer pattern layer has a problem that the reliability and persistence in terms of adhesion and mold release property with the mold and / or substrate when the nanoimprint lithography is used.

Accordingly, an object of the present invention is to provide a photocurable composition having excellent releasability from molds and / or substrates and pattern transfer properties in order to solve the above problems of the photocurable compositions of the prior art.

Another object of the present invention to provide a pattern transfer method using the photocurable composition.

Still another object of the present invention is to provide an optical recording medium manufactured using the photocurable composition.

In order to achieve the above object, one aspect of the present invention,

(a) i) a polyol having at least two hydroxyl groups per molecule; ii) a reactive polydimethylsiloxane comprising at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxy group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane; And iii) 100 parts by weight of urethane-polydimethylsiloxane copolymerized prepolymer formed by the reaction of an aliphatic or aromatic polyisocyanate compound;

Based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer,

(b) 10 to 80 parts by weight of a tetrafunctional (meth) acrylate monomer; And

(c) provides a photocurable composition comprising 0.1 to 10 parts by weight of the photoinitiator.

Another aspect of the present invention to achieve the above another object,

Forming a photocurable composition coating layer on the substrate;

Imprinting the photocurable composition coating layer using a stamper having a predetermined pattern;

Curing the composition by irradiating light capable of photocuring the composition while the stamper is buried in the photocurable composition coating layer; And

A pattern transfer method comprising the step of separating the stamper from the photocurable composition coating layer on the substrate to form a polymer pattern layer on which the pattern of the stamper is transferred on the substrate.

The photocurable composition,

a) i) a polyol having at least two hydroxyl groups per molecule; ii) a reactive polydimethylsiloxane comprising at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxy group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane; And iii) 100 parts by weight of urethane-polydimethylsiloxane copolymer prepolymer formed by the reaction of an aliphatic or aromatic polyisocyanate compound;

Based on 100 parts by weight of the urethane-polydimethylsiloxane copolymer prepolymer,

b) 10 to 80 parts by weight of a tetrafunctional (meth) acrylate monomer; And

c) It provides a pattern transfer method, characterized in that the photocurable composition comprising 0.1 to 10 parts by weight of the photoinitiator.

In order to achieve the above another object, an aspect of the present invention,

materials; And a recording layer formed on the substrate, the optical recording medium comprising:

The recording layer is a polymer pattern layer having a recording mark of a predetermined pattern consisting of a plurality of pits having a nano-size pit depth,

The polymer pattern layer provides an optical recording medium, which is formed by curing the photocurable composition according to the present invention.

The photocurable composition according to the present invention comprises a monofunctional aliphatic thiol compound having 1 to 30 carbon atoms, a monofunctional aliphatic alcohol compound having 1 to 30 carbon atoms, or a mixture thereof, based on 100 parts by weight of the urethane-polydimethylsiloxane copolymer prepolymer. 10 parts by weight may be further included.

The photocurable composition of the present invention is excellent in the releasability and pattern transferability because of its excellent releasability and pattern transferability inherently and excellent in reliability and durability. Therefore, by using the photocurable composition of the present invention, it is possible to improve the productivity of the work of repeatedly transferring the pattern of nano size or micron size. In addition, since the photocurable composition of the present invention does not require an additional process such as low-molecular release agent layer coating separately before applying the same, it is possible to eliminate the problems caused by unevenness of the release agent layer coating or physicochemical instability of the release agent. Therefore, by using the photocurable composition of the present invention, the pattern can be repeatedly repeatedly transferred efficiently onto the substrate using a stamper having a predetermined pattern.

Hereinafter, in the present invention, "release" means that the stamper used as a mold is easily separated from the transferred polymer pattern formed by curing of the photocurable composition without contamination of the stamper used as the mold and damage to the transferred pattern. it means.

Hereinafter, the photocurable composition which concerns on this invention is demonstrated in detail first.

The photocurable compositions of the invention comprise (a) i) a polyol having at least two hydroxy groups per molecule; ii) a reactive polydimethylsiloxane comprising at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxy group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane; And iii) 100 parts by weight of urethane-polydimethylsiloxane copolymerized prepolymer formed by the reaction of an aliphatic or aromatic polyisocyanate compound; Based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer, (b) 10 to 80 parts by weight of a (meth) acrylate monomer having four or less functional groups; And (c) 0.1 to 10 parts by weight of the photoinitiator.

The urethane-polydimethylsiloxane copolymer prepolymer may comprise i) a polyol having two or more hydroxy groups per molecule; ii) a reactive polydimethylsiloxane comprising at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxy group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane; And iii) an aliphatic or aromatic polyisocyanate compound.

In the present invention, the term "urethane-polydimethylsiloxane copolymerized prepolymer" is a polyurethane-polydimethylsiloxane copolymerized prepolymer, polyamidoimide-poly, formed by the reaction of a polyol component and a reactive polydimethylsiloxane with a polyisocyanate compound It means at least one of a dimethylsiloxane copolymerized prepolymer or a polyurea-polydimethylsiloxane copolymerized prepolymer. Among these components, components such as polyurethane, polyamidoimide, and polyurea strengthen the adhesiveness of the photocurable composition of the present invention and the film strength of the polymer pattern layer. In addition, the reactive polydimethylsiloxane component lowers the surface tension of the polymer pattern layer formed by photocuring of the photocurable composition of the present invention so that the photocurable composition of the present invention has inherently excellent releasability. Therefore, when the photocurable composition of the present invention is used, the nanoscale pattern transfer process can be reliably and repeatedly performed without forming a release agent layer before forming the polymer layer using the photocurable composition. Thereby, productivity of a nanoscale pattern transfer process can be improved and manufacturing cost can be reduced.

I) a polyol component, ii) a reactive polydimethylsiloxane; And iii) the component ratio of the polyisocyanate compound is 30 to 70% by weight: 15 to 65% by weight; It is preferable that it is 5-20 weight%. When the content of the polyol component is less than 30% by weight and the content of the polyisocyanate compound is more than 20%, the elasticity of the polymer pattern layer tends to decrease. When the content of the polyol component exceeds 70% by weight and the content of the polyisocyanate compound is less than 5% by weight, the strength of the polymer pattern layer tends to decrease. If the content of the reactive polydimethylsiloxane is less than 15% by weight, the effect of increasing the releasability and pattern transferability intended in the present invention tends to be insufficient. When the content of the reactive polydimethylsiloxane exceeds 65% by weight, there is a problem that the physical properties are difficult to control, such as the viscosity of the composition is too high and the adhesion to the coating is too small.

Specific examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like. Polyester-based polyols include polyethylene adipate, polybutylene adipate, polypropylene adipate, polycaprolactone and the like.

The reactive polydimethylsiloxane includes at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxyl group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane. The number of reactive groups per molecule of this reactive polydimethylsiloxane is not particularly limited, and may be one or more, preferably two or more or three or more. For example, the reactive polydimethylsiloxane may be at least one of those represented by the following formulas (1) to (4).

Here, m and n may be the same or different, respectively, and represent the integer of 1-20, Preferably the integer of 1-10; And

X ₁ To X ₆ may be the same or different, respectively, represent any one of the reactive groups represented by the following formula,

;

;

Here, k, l, o, p, q, r, s, t and u may be the same or different, respectively, each represents an integer of 0 to 10, preferably an integer of 0 to 5, and R is carbon number An alkyl group or an alkoxy group of 1 to 10, preferably an alkyl group or an alkoxy group of 1 to 5 carbon atoms, more preferably an alkyl group or an alkoxy group of 1 to 3 carbon atoms.

When m, n, k, l, o, p, q, r, s, t and u exceed the above values, the viscosity of the photocurable composition tends to increase.

Preferably, the reactive polydimethylsiloxane may be at least one of those represented by the following general formulas (5) to (7) in view of availability and economical efficiency.

Where m, n, o, and r are as defined above.

Polyisocyanate compounds include isophorone diisocyanate, 1,6-hexamethylene diisocyanate 1,8-octamethylene diisocyanate, 1,6-hexamethylene diisocyanate trimer, 4,4'-dicyclohexylmethane diisocyanate, 4, 4'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4-bromo -6-methyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-1,3-phenylene diisocyanate, poly (1,4-butanediol) tolylene 2,4-diisocyanate, poly (1,4-Butanediol) isophorone diisocyanate, poly (ethylene adipate) tolylene-2,4-diisocyanate, 2,4-toluene diisocyanate, 2,5-polene diisocyanate, 2,6- Toluene diisocyanate, 1,5-naphthalene diisocyanate and the like.

A tetrafunctional or less (meth) acrylate type monomer is a component for adjusting the viscosity of a photocurable composition, and providing photocurability to a composition. The functionality of this (meth) acrylate monomer means the number of double bonds such as (meth) acrylate present in one molecule of this monomer. The reactivity of this monomer is 4 or less, Preferably it is 2-4, More preferably, it is 2-3. If the functionality exceeds 4, the crosslinking density at the time of photocuring becomes too large, and the hardness and brittleness of the polymer pattern layer tend to be too large. The content of the (meth) acrylate monomer is preferably 10 to 80 parts by weight based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer. If the content thereof is less than 10 parts by weight, the viscosity of the photocurable composition is too high to facilitate handling, and the crosslinking density at the time of photocuring tends to be small, thereby increasing the time required for photocuring. When the content thereof exceeds 80 parts by weight, the viscosity of the photocurable composition is too low to facilitate handling, and the crosslinking density during photocuring becomes too large, so that the hardness and brittleness of the polymer pattern layer tend to be too large.

Specific examples of the tetrafunctional (meth) acrylate monomers include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxypentyl (meth Monofunctional monomers such as) acrylate and hydroxyhexyl (meth) acrylate; 1,6-hexanediol di (meth) acrylate, triphenyl glycol diacrylate, butanediol diacrylate, 1,3-butylene glycol dimethacrylate, diopentyl glycol diacrylate, ethylene glycol diacrylate, Dimethyl glycol di (meth) acrylate, triethylene glycol diacrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol diacrylate, dipropylene glycol allyl ether methacrylate, methoxylated neopentyl glycol diacryl Difunctional monomers such as rate; Trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate, epoxylated trimethylolpropane triacrylate, propylated trimethylolpropane triacrylate, glyceryl propylated triacrylate, tris (2- Trifunctional or tetrafunctional monomers such as hydroxymethyl) isocyanurate triacrylate and pentaerythritol tetraacrylate.

Photoinitiators may be conventional free radical initiators or cationic initiators or mixtures thereof. It is preferable to use a free radical initiator for the convenience of the reaction step. The free radical initiator initiates photopolymerization of the tetrafunctional (meth) acrylate monomer and the reaction of this monomer with other components by generating radicals by light irradiation. The content of the photoinitiator is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer. When the content thereof is less than 0.1 part by weight, it takes a long time to complete photopolymerization, and when the content thereof exceeds 10 parts by weight, it is difficult to control the heat of polymerization.

Specific examples of photoinitiators used in the present invention include any free radical initiator selected from the group consisting of benzyl ketals, benzoin ethers, acetophenone derivatives, ketoxime ethers, benzophenones, benzo or thioxanthone compounds do. In addition, if it is a normal polymerization initiator which can generate | occur | produce a radical by ultraviolet-ray, it will not specifically limit. The free radical photoinitiator receives ultraviolet rays to generate free radicals, which attack the double bonds of the (meth) acrylate monomers having up to 4 (meth) acrylate functional groups to photopolymerize and other components of the monomer. Causes crosslinking reaction with. Due to such photopolymerization and crosslinking reaction, the photocurable composition loses fluidity while rapidly increasing its molecular weight to form a polymer pattern layer to which the micropattern of the substrate is transferred.

The photocurable composition according to the invention is an aliphatic thiol compound having 1 to 30 carbon atoms, preferably an aliphatic thiol compound having 3 to 20 carbon atoms and / or an aliphatic alcohol compound having 1 to 30 carbon atoms, preferably an aliphatic alcohol having 3 to 20 carbon atoms The compound may further comprise 0.1 to 10 parts by weight. Their content is 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer. These can form a self-assembled monolayer on the surface of the stamper used as a mold to increase the releasability of the substrate. Preferred examples thereof include propyl mercaptan, butyl mercaptan, lauryl mercaptan, stearyl mercaptan, propyl alcohol, butyl alcohol, cetyl alcohol, lauryl alcohol, stearyl alcohol and the like.

The photocurable composition used in the present invention may also contain an appropriate amount of additives such as known stabilizers, antioxidants, thermosetting agents, surfactants, leveling agents and the like as necessary.

Next, the preparation method of the photocurable composition concerning this invention is demonstrated.

First, a polyol having two or more hydroxyl groups per molecule, a reactive polydimethylsiloxane, and an aliphatic or aromatic polyisocyanate compound are mixed and stirred to proceed with the polyurethane polymer formation reaction. In this reaction, the polyisocyanate compound reacts with the hydroxyl group of the polyol component and the reactive group of the reactive polydimethylsiloxane, thereby making the polyurethane-polydimethylsiloxane copolymerized prepolymer, polyamidoimide, referred to herein as "urethane-polydimethylsiloxane copolymerized prepolymer" for convenience. At least one of a polydimethylsiloxane copolymerized prepolymer or a polyurea-polydimethylsiloxane copolymerized prepolymer is formed.

This reaction usually proceeds in bulk without the use of a solvent. The reaction temperature is controlled from room temperature to 70 ° C, preferably from 30 ° C to 60 ° C. The higher the reaction temperature, the faster the reaction rate. The reaction time is usually 1 hour to 12 hours, preferably 1 hour to 6 hours. Side reactions may occur when the reaction time is too long or when the reaction temperature is too high.

The polyol component: the reactive polydimethylsiloxane: the mixing ratio of the polyisocyanate compound is adjusted to 30 to 70% by weight: 15 to 65% by weight: 5 to 20% by weight. The urethane-polydimethylsiloxane copolymerized prepolymer thus obtained can have excellent coating film strength and adhesiveness of components such as polyurethane, polyamidoimide, and / or polyurea and excellent release properties of the polydimethylsiloxane component.

Subsequently, based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer thus formed, 10 to 80 parts by weight of the (meth) acrylate monomer having 4 or less functional groups at room temperature to 60 ° C, preferably at room temperature to 40 ° C. Mix and stir to homogenize. The stirring time for homogenization is not particularly limited, but 0.5 hours to 2 hours is sufficient.

On the other hand, when the photocurable composition of the present invention contains an aliphatic thiol compound and / or an aliphatic alcohol compound for forming a self-assembled monolayer film, the room temperature to 40 ℃, after mixing or completion of the (meth) acrylate monomer, Preferably it is added at room temperature to 25 ° C. and homogenized. The amount of the thiol compound and / or the aliphatic alcohol compound is 0.1 to 10 parts by weight based on 100 parts by weight of the urethane-polydimethylsiloxane copolymer prepolymer. The stirring time for homogenization is not particularly limited but is 0.5 hours to 2 hours.

Finally, 0.1-10 parts by weight of the photoinitiator is added to the resultant at room temperature to 40 ° C, preferably at room temperature to 25 ° C, and homogeneous. The stirring time for homogenization is not particularly limited but is 0.5 hours to 2 hours. As such, when the mixing of all the components of the composition of the present invention is completed, the air bubbles contained in the composition are removed by a conventional method such as pumping the composition.

Next, the pattern transfer method using the photocurable composition of this invention is demonstrated.

1 is a schematic cross-sectional view for explaining a pattern transfer method and a structure of an optical disc formed thereby according to an embodiment of the present invention.

First, the metal layer 4 is formed using a conventional method such as sputtering to increase the reflectance on the substrate 1 having a predetermined pit pattern, commonly referred to as "L0 recording layer" by those skilled in the art. The substrate 1 may be appropriately selected from an acrylic resin film such as an amorphous polyolefin film, a polyester film, a polycarbonate film, a polymethyl methacrylate film, an epoxy resin film, a glass substrate, or the like depending on the use. Preferably, the substrate 1 is transparent and does not prevent the irradiated light from reaching the photocurable composition. The metal layer 4 may be gold, silver, nickel, copper or an silver-based alloy. The layer thickness of the metal layer 4 is usually 200 nm or less, preferably 100 nm or less. Silver-based alloys may be preferable in terms of increased reflectance and adhesion. The silver-based alloy is preferably a silver-palladium-copper (APC) alloy. In particular, a silver-palladium-copper (APC) alloy having a silver content of 90 to 99% by weight, a palladium content of 0.5 to 5% by weight and a copper content of 0.5 to 5% by weight may be preferably used.

Subsequently, a photocurable composition coating layer (not shown) according to the present invention is formed on the metal layer 4. The coating method is not particularly limited, but usually consists of a spin coating method.

A stamper 3 having a predetermined pattern is prepared. The stamper 3 is used to transfer the pattern in large quantities using the imprint method. Methods for producing a stamper having a predetermined pattern using a method such as photolithography are well known in the art. The substrate 1 and the stamper 3 are made to face each other with the predetermined pattern of the stamper 3 facing the substrate, and then the photocurable composition coating layer on the substrate 1 is imprinted using the stamper 3 as a mold.

Subsequently, in the state where the stamper 3 is buried in the photocurable composition coating layer, light capable of photocuring the composition is irradiated to cure the composition. When both the base material 1 and the stamper 3 are permeable, light can be irradiated from at least one of the directions (A direction or B direction) to cure the photocurable composition. Irradiation light passes through the stamper and / or substrate to reach the photocurable composition to initiate photopolymerization of the composition. The light used for photocuring the photocurable composition depends on the type of photopolymerizable monomer or prepolymer or photopolymerization initiator used, but includes ultraviolet rays, visible rays, infrared rays, electron beams, and the like. By the curing by photopolymerization, the predetermined pattern of the stamper is transferred to the photocurable composition coating layer to form the polymer pattern layer 5.

Finally, when the stamper 3 is separated from the photocurable composition pattern layer 5 on the substrate, the formation of the polymer pattern layer 5 on which the stamper pattern is transferred on the substrate 1 is completed. At this time, the protrusion of the stamper is transferred to the recessed part (pit) in the polymer pattern layer. That is, the positive image of the stamper is transferred to the negative image on the substrate.

When manufacturing a high density optical recording medium having a plurality of recording layers, such as a multilayer optical disk, a dielectric layer (not shown) is formed on the polymer pattern layer 5 to increase the reflectance, and then the polymer pattern layer is formed by the imprinting method described above. Repeat the process to form. The layer thickness of the dielectric layer varies depending on the type of material, but is usually 500 nm or less, preferably 300 nm or less, more preferably 200 nm or less, even more preferably 150 nm or less.

When the pattern transfer method of the present invention is used to form a recording layer of an optical recording medium or a magnetic recording medium, the stamper pattern has a height of 20 nm to 100 nm, preferably a height of 50 nm to 100 nm, more preferably 50 nm to The pattern may be formed by a plurality of protrusions having a height of 80 nm. By imprinting the photocurable composition coating layer using such a stamper, information of a predetermined pattern consisting of a plurality of pits having a pit depth of 20 nm to 100 nm, preferably 50 nm to 100 nm, more preferably 50 nm to 80 nm A recording mark is formed on the polymer pattern layer 5 on the substrate.

An optical recording medium obtained by the present invention shown in the lower part of FIG. 1 includes: a base material 1; And a recording layer formed on the substrate, the recording layer having a predetermined pattern of information recording marks consisting of a plurality of pits having a pit depth of 20 nm to 100 nm, preferably 50 nm to 100 nm. It is a polymer pattern layer 5, and the polymer pattern layer 5 is formed by curing the photocurable composition according to the present invention.

On the surface of the substrate 1, the L0 recording layer pattern shown by the uneven pattern of the surface of the substrate 1 in FIG. When manufacturing a high density optical recording medium having a plurality of recording layers, such as a multilayer optical disk, a dielectric layer (not shown) is formed on the polymer pattern layer (5, L1 recording layer) by a method known in the art such as sputtering. After that, the process of forming the polymer pattern layer (not shown) is repeated according to the imprint method. The dielectric layer serves as a thermal and mechanical protective layer and is made of at least one of oxides, nitrides, carbides, and fluorides. Specific examples thereof include silicon oxide (SiOx), magnesium oxide (MgOx), aluminum oxide (AlOx), titanium oxide (TiOx), vanadium oxide (VOx), chromium oxide (CrOx), nickel oxide (NiOx), and cornium oxide ( ZrOx, Germanium Oxide (GeOx), Zinc Oxide (ZnOx), Silicon Nitride (SiNX), Aluminum Nitride (AlNx), Titanium Nitride (TiNx), Cornium Nitride (ZrNx), Germanium Nitride (GeNx), Silicon Carbide (SiC) Zinc sulfide (ZnS), zinc sulfide-silicon dioxide compounds (ZnS-SiO 2), and magnesium fluoride (MgF ₂ ). When the dielectric layer is made of zinc sulfide-silicon dioxide compound (ZnS-SiO ₂ ), the molar ratio of ZnS to SiO ₂ can obtain the best properties at 8: 2.

Although described in detail in the following Examples, using the photocurable resin composition of the present invention excellent in the releasability and pattern transfer properties, even if the transfer of the nano-size pattern using the same stamper, the pattern transfer process described above on the substrate It may be repeated at least 50 times. The recording and reproducing characteristics of the polymer pattern layer obtained by imprinting once using a stamper having the same pattern and the polymer pattern layer obtained by imprinting 50 times can be almost the same. Therefore, according to the pattern transfer method using the photocurable resin composition of the present invention, it is possible to efficiently mass-produce a high density optical disk or a magnetic recording medium having a plurality of information recording layers on a substrate. Each polymer pattern may be the same pattern or different patterns.

Hereinafter, the present invention will be described in more detail with reference to Examples. This is for the purpose of illustrating the invention is not intended to limit the scope of the invention thereby.

Preparation  1-6

The photocurable compositions A to F were prepared in the following compositions and contents. First, a polypropylene glycol (LAPROL 3000) and a polydimethylsiloxane (X-22-160C) in which the sock end was blocked with a hydroxy group at 30 ° C. to 35 ° C. in a reactor equipped with a stirrer and temperature controlled by a water jacket. 6-hexamethylene diisocyanate (HMDI) and 1,6-hexamethylene isocyanate trimer (CORONATE HX) were mixed and stirred well for 4 hours to obtain a urethane-polydimethylsiloxane copolymerized prepolymer. 1,6-hexanediol diacrylate (HDDA), hydroxypropyl methacrylate, trimethoxypropyl tetraacrylate, hydroxyethyl acrylate, 2 while maintaining the temperature of the copolymerized prepolymer at about 40 ℃ to 42 ℃ Hydroxyethyl methacrylate (HEMA) was added and stirred for about 2 hours to mix well. The mixture was charged with polydimethylsiloxane (DC-1248) having a secondary hydroxyl group at room temperature and stirred for about 1 hour. Finally, a photoinitiator (IRGACURE 907) was added to the resultant at room temperature, and further stirred for 1 hour, followed by degassing using a vacuum pump to prepare photocurable compositions A to F.

TABLE 1

Photocurable Composition A (parts by weight) Photocurable Composition B (parts by weight) Photocurable Composition C (parts by weight) Photocurable Composition D (parts by weight) Photocurable Composition E (parts by weight) Photocurable Composition F (parts by weight) Polypropylene Glycol (LAPROL 3000) ^{# 1} 30 33 27.2 20.4 28 35 Dimethylsiloxane with Secondary Hydroxy Group (DC-1248) ^{# 2} 2 6 40.8 25.7 8 2 Polydimethylsiloxane (X-22-160C) ^{# 3} Terminal Blocked with Hydroxy Group 10 6 4.5 5 - 1.5 1,6-hexamethylene diisocyanate (HMDI) 8.5 6.8 4.5 8.5 7.5 9.5 1,6-hexamethylene diisocyanate trimer (CORONATE HX) ^{# 4} 0.2 One 0.2 0.2 2 1.8 1,6-hexanediol diacrylate (HDDA) 20.5 10 13 10.5 18 20 Hydroxypropyl methacrylate 3 5.6 3 - 5.5 4.8 Trimethoxypropyl tetraacrylate 2.6 13 - 9 8 7.5 Hydroxyethyl acrylate 2 5.7 3 4.5 2.5 1.8 2-hydroxyethyl methacrylate (HEMA) 6.7 6.7 - 11 2 8.1 Photoinitiator (IRGACURE 907) ^{# 5} 2.7 4 2.7 2.7 1.5 8

# 1: Buy at Hitachi Kasei.

# 2: Buy from Dow Corning Corporation.

# 3: Buy from Shin-Etsu Corporation.

# 4: Buy from Degusa AG.

# 5: Purchased from Ciba Specialty Chemicals.

Example  One

This embodiment is for explaining the principle of manufacturing an optical disk by carrying out multi-layer pattern transfer on a substrate using a plastic stamper and a photocurable resin composition A prepared in advance according to a conventional method as a mold. Figure 2a shows an atomic force microscope (AFM) picture of the plastic stamper used in this embodiment. Bright portions in this photograph represent a plurality of protrusions for forming a pit pattern on the substrate. FIG. 2B shows the profile of the pit depth of the protrusion and non-projection patterns measured by scanning along the line A indicated on the picture of FIG. 2A. The pit average depth scanned along line A in the stamper was 73.2 nm. This AFM photo and pit depth profile were obtained using Park Scientific Instrument's Autoprobe M5.

A silver-palladium-copper (APC) alloy layer having an average thickness of 30 nm was formed on the L0 recording layer of a predetermined pattern formed on the surface of a circular polycarbonate transparent substrate having a thickness of 1.1 mm and a diameter of 12 cm. In this APC alloy, the silver content was 98% by weight, the palladium content was 1% by weight and the copper content was 1% by weight. Subsequently, 1.2 g of photocurable composition A was added and spin-coated on this alloy layer. At this time, by adjusting the rotational speed of the spin coater to about 4,000 rpm to adjust the film thickness of the photocurable composition A to about 20 ~ 30㎛.

Subsequently, the photocurable composition A layer on the substrate was imprinted using the stamper. Subsequently, ultraviolet rays having a wavelength of 200 to 450 nm were irradiated from the transparent substrate side for 10 seconds with an energy of 2,000 mJ / cm 2 to cure the photocurable composition A and to separate the stamper from the substrate. As a result, a polymer pattern layer was formed on the substrate.

3 illustrates a polymer pattern layer formed on a substrate by imprinting once as described above. 3A shows an atomic force microscope (AFM) photograph of a polymer pattern layer formed on a substrate. The dark part in this photograph represents a pit imprinted by the protrusion of the stamp. FIG. 3B shows a profile of pit depth measured by scanning along a specific line on the picture of FIG. 3A. The pit average depth of this stamper was 73 nm. In addition, jitter was measured using the Time Interval Analyzer TA 720 of Yokogawa Electric Corporation for the transfer pattern shown in FIG. 3A. The jitter was 8.1%.

The nanopattern transfer test as described above for the photocurable composition A was repeated 50 times using the stamper continuously without replacing the stamper. 4 illustrates a polymer pattern layer formed on a substrate when imprinted 50 times. 4A shows an AFM photograph of a polymer pattern layer formed on a substrate. The dark part in this photograph represents a pit imprinted by the protrusion of the stamp. 4B shows a profile of pit depth measured by scanning along a specific line on the picture of FIG. 4A. The pit average depth of this stamper was 72.5 nm. In addition, jitter was measured using the Time Interval Analyzer TA720 of Yokogawa Electric Corporation for the transfer pattern shown in FIG. 4A. The jitter was 8.1%.

Comparing the first and 50th nanopattern transfer tests described above, it was found that the pit depth and jitter value of the polymer pattern layer were almost constant. In addition, it can be seen that the pit depth of the nanopatterns transferred at the first and the 50th times is almost the same as the pit depth of the stamper.

No contamination was observed in the stamper after 50 imprints. In addition, no collapse of the polymer pattern layer that occurred when the releasability and transferability were insufficient during 50 imprints.

Next, in five-layer recording using the photocurable composition A as the imprint resin in the manufacture of the optical disc by the multilayer recording, the tilt characteristic caused by the shrinkage of the resin generated during photocuring was evaluated. It was. The above-described APC alloy layer was formed on the L0 recording layer, and a zinc sulfide-silicon dioxide compound (ZnS-SiO2) dielectric layer having an average thickness of 130 nm was formed between each layer of the L1 to L5 recording layer (polymer pattern layer). Tilt characterization was performed by measuring radial tilt and tangential tilt using equipment manufactured by the present inventors. Table 2 shows the tilt measurement results.

TABLE 2

Measuring position  L0 layer  L5 layer  Δ Radius (mm) Radial tilt Tangential tilt Radial tilt (deg) Tangential Tilt (deg) Radial tilt (deg) Tangential Tilt (deg) 25 0.233 0.067 0.167 0.067 0.067 0 30 0.267 0.067 0.233 0.067 0.033 0 35 0.267 0.067 0.300 0.067 0.033 0 40 0.300 0.067 0.333 0.067 0.033 0 45 0.300 0.067 0.367 0.067 0.067 0 50 0.333 0.067 0.367 0.067 0.033 0 55 0.367 0.067 0.367 0.067 0 0

As can be seen from Table 2, when the tilt values in the L0 layer and the L5 layer were compared, it was confirmed that the difference in the tilt values in both layers was very excellent as 0.1 deg (°) or less.

Example  2

This embodiment is intended to explain the principle of manufacturing an optical disc by multi-layer pattern transfer on a substrate in the same manner as in Example 1 using a plastic stamper and a photocurable composition B prepared in advance according to a conventional method as a mold.

FIG. 5A shows an atomic force microscope (AFM) photograph of the plastic stamper used in this example. The bright portions in this photograph represent protrusions for forming a pit pattern on the substrate. FIG. 5B shows the profile of the pit depth of the protrusion and non-projection patterns measured by scanning along the line A indicated on the picture of 6a. The pit average depth scanned along the line A in the stamper was 73 nm. This AFM photo and pit depth profile were obtained using Park Scientific Instrument's Autoprobe M5.

FIG. 6 shows the polymer pattern layer formed on the substrate when the imprint test was repeated 50 times for the photocurable composition B without using the stamper continuously. 6A shows an AFM photograph of a polymer pattern layer formed on a substrate. The dark part in this photograph represents a pit imprinted by the protrusion of the stamp. FIG. 6B shows the profile of the pit depth measured by scanning along line A on the picture of FIG. 6A. The transferred pit average depth measured along line A was 72.5 nm. No contamination was observed in the stamper after 50 imprints. In addition, no collapse of the polymer pattern layer was observed during 50 imprints.

As in Example 1, the jitter value measured using the apparatus was 8.2% both after the first imprint and after 50 imprints. The tilt characteristic evaluation at the time of five-layer recording also showed similar results as in Example 1.

Example  3

This embodiment is for explaining the principle of manufacturing an optical disc by performing a multi-layer pattern transfer on a substrate in the same manner as in Example 1 using the plastic stamper and the photocurable composition C used in Example 1 as a mold.

No contamination was observed in the stamper after 50 imprints. In addition, no collapse of the polymer pattern layer was observed during 50 imprints.

As in Example 1, the jitter value measured using the apparatus was 7.9% both after the first imprint and after 50 imprints. The tilt characteristic evaluation at the time of five-layer recording also showed similar results as in Example 1.

Example  4

This embodiment is for explaining the principle of manufacturing an optical disc by performing a multi-layer pattern transfer on a substrate in the same manner as in Example 1 using the plastic stamper and the photocurable composition D used in Example 1 as a mold.

The stamper was free from contamination even after 50 imprints. In addition, no collapse of the polymer pattern layer was observed during 50 imprints.

As in Example 1, the jitter value measured using the apparatus was 8.2% both after the first imprint and after 50 imprints. The tilt characteristic evaluation at the time of five-layer recording also showed similar results as in Example 1.

Comparative example  One

The pattern transfer was performed on the substrate using the plastic stamper used in Example 1 according to the same method as Example 1, except that the photocurable composition E was used instead of the photocurable composition A.

However, the release property of the stamper and the pattern transferability were poor. That is, the surface of the stamper was contaminated by polymer debris, and collapse was observed in a part of the polymer pattern layer formed on the substrate.

Comparative example  2

A pattern transfer was performed on the substrate using the plastic stamper used in Example 1 according to the same method as Example 1, except that the photocurable composition F was used instead of the photocurable composition A.

However, the release property and pattern transfer property of the stamper were poor. That is, the surface of the stamper was contaminated by polymer debris, and collapse was observed in a part of the polymer pattern layer formed on the substrate.

From the results of the above Examples 1 to 4, it was confirmed that the photocurable resin composition according to the present invention can be repeatedly repeatedly transferred efficiently by the imprint method even with a fine pattern such as a nano size pattern because of excellent releasability and transferability. . Therefore, the photocurable resin composition of this invention can significantly improve the productivity of a high density optical disc manufacture. However, from the results of Comparative Examples 1 and 2, when the reactive polydimethyl siloxane was not used or the photocurable composition having a low content was used, it was confirmed that the transferability and the releasability were poor in order to efficiently perform the nanosize pattern transfer.

The photocurable composition of the present invention and the pattern transfer method using the same can be used for the production of optical recording media such as optical disks or magnetic recording media, semiconductor devices, display devices, ultra-fine electrical and electronic devices, and the like.

1 is a schematic cross-sectional view for explaining a pattern transfer method and a structure of an optical disc formed thereby according to an embodiment of the present invention.

Figure 2a shows an atomic force microscope (AFM) picture of the plastic stamper used in the pattern transfer method according to an embodiment of the present invention.

FIG. 2B shows the profile of the pit depth of the protrusion and non-projection patterns measured by scanning along the line A indicated on the picture of FIG. 2A.

Figure 3a shows an atomic force microscope (AFM) photograph of the polymer pattern layer formed on the substrate in the pattern transfer method according to an embodiment of the present invention.

FIG. 3B shows a profile of pit depth measured by scanning along a specific line on the picture of FIG. 3A.

Figure 4a shows an atomic force microscope (AFM) picture of the polymer pattern layer formed on the substrate when the imprint test is repeated 50 times in the pattern transfer method according to an embodiment of the present invention.

4B shows a profile of pit depth measured by scanning along a specific line on the picture of FIG. 4A.

5A shows an AFM image of a plastic stamper used in a pattern transfer method according to another embodiment of the present invention.

FIG. 5B shows the profile of the pit depth of the protrusion and non-projection patterns measured by scanning along the line A indicated on the photograph of 5a.

6A shows an AFM photograph of a polymer pattern layer formed on a substrate when an imprint test is repeated 50 times in a pattern transfer method according to another embodiment of the present invention.

FIG. 6B shows the profile of the pit depth measured by scanning along line A on the picture of FIG. 6A.

<Brief description of the major symbols in the drawings>

1: base material 3: stamper

5: polymer pattern layer

Claims (18)

(a) (i) a polyol having at least two hydroxyl groups per molecule; (ii) a reactive polydimethylsiloxane comprising at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxyl group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane; And (iii) 100 parts by weight of urethane-polydimethylsiloxane copolymerized prepolymer formed by the reaction of an aliphatic or aromatic polyisocyanate compound; Based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer, (b) 10 to 80 parts by weight of a tetrafunctional (meth) acrylate monomer; And (c) Photocurable composition comprising 0.1 to 10 parts by weight of the photoinitiator. According to claim 1, 0.1 to 10 weight percent of a monofunctional aliphatic thiol compound having 1 to 30 carbon atoms, a monofunctional aliphatic alcohol compound having 1 to 30 carbon atoms, or a mixture thereof, based on 100 parts by weight of the urethane-polydimethylsiloxane copolymerized prepolymer. It further comprises a photocurable composition. The photocurable composition according to claim 1, wherein the component ratio of the polyol component: the reactive polydimethylsiloxane: the polyisocyanate compound is 30 to 70% by weight: 15 to 65% by weight: 5 to 20% by weight. The photocurable composition according to claim 1, wherein the polyol is a polyether polyol, a polyester polyol or a mixture thereof. The photocurable composition according to claim 1, wherein the reactive polydimethylsiloxane is at least one of the following formulas (1) to (4):

Here, m and n may be the same or different, respectively, and represent the integer of 1-20; X ₁ To X ₆ may be the same or different, represents at least one of the reactive groups represented by the following formula,

, Here, k, l, o, p, q, r, s, t and u may be the same or different, and represent an integer of 0 to 10, and R represents an alkyl or alkoxy group having 1 to 10 carbon atoms. The photocurable composition of claim 1, wherein the photoinitiator is a free radical initiator or a cationic initiator. Forming a photocurable composition coating layer on the substrate; Imprinting the photocurable composition coating layer using a stamper having a predetermined pattern; Curing the composition by irradiating light capable of photocuring the composition while the stamper is buried in the photocurable composition coating layer; And A pattern transfer method comprising the step of separating the stamper from the photocurable composition coating layer on the substrate to form a polymer pattern layer on which the pattern of the stamper is transferred on the substrate. The photocurable composition, a) i) a polyol having at least two hydroxyl groups per molecule; ii) a reactive polydimethylsiloxane comprising at least one reactive group selected from the group consisting of an amino group, an epoxy group, a carboxyl group, a hydroxy group, a halogen atom, a thiol group, and a (meth) acrylate group at the side chain or the terminal of the polydimethylsiloxane; And iii) 100 parts by weight of urethane-polydimethylsiloxane copolymer prepolymer formed by the reaction of an aliphatic or aromatic polyisocyanate compound; Based on 100 parts by weight of the urethane-polydimethylsiloxane copolymer prepolymer, b) 10 to 80 parts by weight of a tetrafunctional (meth) acrylate monomer; And c) Pattern transfer method, characterized in that the photocurable composition containing 0.1 to 10 parts by weight of the photoinitiator. According to claim 7, wherein the photocurable composition based on 100 parts by weight of the urethane-polydimethylsiloxane copolymer prepolymer is a monofunctional aliphatic thiol compound having 1 to 30 carbon atoms, a monofunctional aliphatic alcohol compound having 1 to 30 carbon atoms, or a mixture thereof Pattern transfer method comprising more than 0.1 to 10 parts by weight. The method of claim 7, wherein the component ratio of the polyol component: the reactive polydimethylsiloxane: the polyisocyanate compound is 30 to 70% by weight: 15 to 65% by weight: 5 to 20% by weight. The method of claim 7, wherein the polyol is a polyether polyol, a polyester polyol or a mixture thereof. The pattern transfer method according to claim 7, wherein the reactive polydimethylsiloxane is at least one of those represented by the following general formulas (1) to (4):

Here, m and n may be the same or different, and represent the integer of 1-20; X ₁ To X ₆ may be the same or different, represents any one of the reactive groups represented by the following formula,

k, l, o, p, q, r, s, t and u may be the same or different, respectively, and represent an integer of 0 to 10, respectively, and R represents an alkyl or alkoxy group having 1 to 10 carbon atoms. 8. The method of claim 7, wherein the photoinitiator is a free radical initiator or a cationic initiator. The method of claim 7, wherein the stamper pattern is a pattern transfer method, characterized in that the pattern consisting of a plurality of protrusions having a height of 20 nm ~ 100 nm. The method of claim 7, wherein the pattern transferred to the polymer pattern layer is a recording mark of an optical recording medium. The method of claim 7, wherein the substrate is a polyolefin film, a polyester film, a polycarbonate film, an acrylic resin film, an epoxy resin film or a glass substrate. materials; And a recording layer formed on the substrate, the optical recording medium comprising: The recording layer is a polymer pattern layer having a recording mark of a predetermined pattern consisting of a plurality of pits having a pit depth of 20 nm to 100 nm, The polymer pattern layer is an optical recording medium, characterized in that formed by curing the photocurable composition according to any one of claims 1 to 6. The optical recording medium according to claim 16, wherein the polymer pattern layer is present in plural layers. 18. The optical recording medium according to claim 17, wherein a dielectric layer is formed between the plurality of polymer pattern layers.

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