TWI461504B - Adhesive sheet for mold fixing, adhesive tape for mold fixing, and manufacturing method of fine structure - Google Patents

Description

Adhesive sheet for mold fixing, adhesive tape for mold fixing, and manufacturing method of fine structure

The present invention relates to an adhesive sheet and an adhesive tape for fixing a mold used in imprint lithography, and a method for producing a fine structure.

Recently, an imprint lithography system which can efficiently form a fine pattern on the surface of a substrate to increase throughput has been attracting attention. The lithography method forms a film composed of a curable resin composition on the surface of the substrate, presses the surface of the film with a mold, transfers the fine pattern of the mold, and hardens the film of the transferred fine pattern. A method of forming a fine pattern on the surface of the substrate (for example, see Non-Patent Document 1).

Since the fine pattern formed by the lithography corresponds to the fine pattern of the mold used, the importance of the mold in the imprint lithography is quite high. The mold is usually used in a state where it is fixed to the pedestal by a jig such as a vacuum chuck or a mechanical chuck.

However, in order to set the vacuum chucking mechanism to the pedestal, it is necessary to perform microfabrication on the pedestal, which has a problem of an increase in cost. Further, when the outer peripheral portion of the mold is fixed by a mechanical chuck, the center portion of the mold is deflected by its own weight, and there is a problem that the surface smoothness of the mold cannot be ensured. Imprint lithography with a mold with a smooth surface does not provide sufficient transfer accuracy. This problem is quite significant in large molds.

On the other hand, it is considered that if an adhesive sheet or an adhesive tape is used instead of a vacuum chuck or a mechanical chuck as a fixing means for the mold, the problem caused by the above clamp should be solved.

However, an adhesive sheet or an adhesive tape composed of a general acrylic adhesive has the following problems. In other words, when a UV curable resin composition is used as the curable resin composition, for example, after the film is cured by UV irradiation, the mold is vertically peeled off from the cured film. However, if the film is hardened, it is difficult to peel the mold, so that a large load is applied to the above-mentioned adhesive sheet or the adhesive tape during the vertical peeling. Generally, the adhesive sheet and the adhesive tape have insufficient fixing force to the mold, and if the load is applied, the mold will fall off from the adhesive sheet or the adhesive tape. In addition, since the general adhesive sheet and the adhesive tape system cannot be reused, the economy is low.

[Non-Patent Document 1] Matsui Shinji, "Nano Imprinting Micro-Film Technology", Surface Science, Vol25, No. 10, pp628-634, 2004

An object of the present invention is to provide an adhesive sheet for mold fixing, an adhesive tape for mold fixing, and a method for producing a fine structure in which a mold can be fixed with a high fixing force while ensuring smoothness of the surface.

The adhesive sheet for mold fixing of the present invention contains a side chain crystalline polymer as a main component. The side chain crystalline polymer is crystallized at a temperature at which the melting point is not reached, and exhibits fluidity at a temperature above the melting point, and the storage elastic modulus G' at the melting point + 10 ° C is 1 × 10 ² Up to 1 × 10 ⁵ Pa.

The adhesive tape for mold fixing of the present invention is formed by providing an adhesive layer on both surfaces of a base film, and at least the adhesive layer on the side of the mold is composed of the above-mentioned adhesive sheet for mold fixing.

The manufacturing method of the fine structure of the present invention uses the aforementioned adhesive sheet for mold fixing, and includes the following steps (i) to (iv):

(i) the step of interposing the aforementioned adhesive sheet between the mold and the pedestal;

(ii) a step of fixing the mold to the pedestal via the adhesive sheet after the temperature of the adhesive sheet is equal to or higher than the melting point of the side chain crystalline polymer, and the temperature is not at the temperature of the melting point ;

(iii) a step of pressurizing the surface of the film composed of the curable resin composition by a fixed mold to transfer the fine pattern of the mold;

(iv) a step of curing the film of the transferred fine pattern to obtain a fine structure.

Further, the "sheet" in the present invention is not limited to a sheet shape, and the concept of a sheet shape or a film shape is not included as long as the effect of the present invention is not impaired.

According to the present invention, since the mold is fixed to the pedestal by the adhesive sheet or the adhesive tape, the pedestal does not need to be processed as in the prior art, so that the cost can be reduced, and the mold can be fixed to the pedestal while ensuring the smoothness of the surface.

Further, the adhesive layer of the adhesive sheet or the adhesive tape of the present invention reversibly becomes a crystalline state and a flowing state corresponding to a temperature change, and contains a side chain crystal having a specific value in a storage elastic modulus G' in a flowing state. The polymer is the main component. Since the side chain crystalline polymer exhibits high fluidity in a flowing state, the aforementioned adhesive sheet or adhesive tape containing the side chain crystalline polymer as a main component penetrates well on the surface of the mold or the pedestal. The fine concavities and convexities or voids can exhibit a so-called anchor effect in the process of changing from a flowing state to a crystalline state, resulting in a high fixing force. Therefore, if the adhesive sheet or the adhesive tape is used, even if a large load is applied during the process of vertically peeling the mold from the hardened film, the mold can be prevented from falling off. Further, since the adhesive sheet or the adhesive tape is a phase changer using a side chain crystalline polymer, it can be reused.

<Adhesive sheet for mold fixing>

The adhesive sheet for mold fixing of the present invention (hereinafter sometimes referred to as "adhesive sheet") contains a side chain crystalline polymer as a main component. The side chain crystalline polymer is crystallized at a temperature not at the melting point, and undergoes phase transfer at a temperature equal to or higher than the melting point to exhibit fluidity. In other words, the side chain crystalline polymer is reversibly in a crystalline state and a flowing state in response to a change in temperature.

The side chain crystalline polymer has a storage elastic modulus G' of from 1 × 10 ² to 1 × 10 ⁵ Pa at a melting point of +10 ° C, and preferably 2 × 10 ² to 9 × 10 ⁴ Pa. Thereby, the side chain crystalline polymer in a flowing state exhibits high fluidity, and the aforementioned adhesive sheet containing the side chain crystalline polymer as a main component also exhibits high fluidity. As a result, the above-mentioned adhesive sheet penetrates seamlessly into fine irregularities or voids existing on the surface of the mold or the pedestal. When the adhesive sheet in this state is cooled to a temperature that does not reach the melting point, the side chain crystalline polymer exhibits a anchoring effect due to crystallization, so that a high fixing force can be obtained.

On the other hand, if the storage elastic modulus G' at the melting point + 10 ° C is less than 1 × 10 ² Pa, the cohesive force of the adhesive sheet is lowered, and the fixing force is also lowered. Further, when the storage elastic modulus G' is more than 1 × 10 ⁵ Pa, the fluidity of the side chain crystalline polymer is lowered, so that it is difficult to obtain the anchoring effect and the fixing force is lowered.

The side chain crystalline polymer preferably has a storage elastic modulus G' at the melting point of -10 ° C of from 1 × 10 ⁵ to 1 × 10 ⁹ Pa, preferably from 1 × 10 ⁶ to 1 × 10 ⁸ Pa. Thereby, the elasticity required to visualize the aforementioned anchoring effect can be ensured. Further, since the side chain crystalline polymer in the crystalline state has moderate elasticity, the above-mentioned adhesive sheet can function as a cushioning material. Therefore, it is possible to follow the bending or the micro bumps of the substrate, and the transfer failure can be prevented.

On the other hand, if the storage elastic modulus G' at the melting point of -10 ° C is too small, the elasticity of the side chain crystalline polymer in the crystal state may be insufficient, and it may be difficult to obtain the anchoring effect. Further, if the storage elastic modulus G' is too large, it is difficult for the adhesive sheet to function as a cushioning material, which is not preferable. The storage elastic modulus G' is a value measured by a dynamic viscoelasticity measuring device as described in the synthesis example described later.

Here, the aforementioned melting point of the side chain crystalline polymer means a temperature at which a specific portion of the polymer which is initially integrated into an orderly arrangement is disordered by a certain balancing procedure, by means of the difference The value measured by a scanning calorimeter (DSC) under the measurement conditions of 10 ° C / min.

The above melting point is preferably 30 to 70 ° C and preferably 30 to 60 ° C. When the melting point is too low, when the temperature changes when the mold is fixed and the temperature rises, the ambient temperature easily exceeds the melting point, and the side chain crystalline polymer exhibits fluidity, so that the fixing force is lowered and the mold is lowered. Will fall off the adhesive sheet. Further, when the melting point is too high, a large amount of thermal energy is required in order to bring the side chain crystalline polymer into a flowing state, which is disadvantageous in terms of economy.

When the storage elastic modulus G' and the melting point are to be specific values, the composition or molecular weight of the side chain crystalline polymer can be arbitrarily changed. The composition of the above-mentioned side chain crystalline polymer may be, for example, 20 to 100 parts by weight of a (meth) acrylate having a linear alkyl group having 16 or more carbon atoms, and an alkyl group having 1 to 6 carbon atoms. a polymer obtained by polymerizing 0 to 70 parts by weight of an acrylate and 0 to 10 parts by weight of a polar monomer.

The (meth) acrylate having a linear alkyl group having 16 or more carbon atoms may, for example, be cetyl (meth) acrylate, stearyl (meth) acrylate or eicosyl (meth) acrylate. (meth) acrylate having a linear alkyl group having 16 to 22 carbon atoms such as behenyl (meth) acrylate, and the (meth) acrylate having an alkyl group having 1 to 6 carbon atoms can be exemplified For example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, etc., and the polar monomer may, for example, be acrylic acid, methacrylic acid or croton. Ethylene-unsaturated monomer containing carboxyl group such as acid, itaconic acid, maleic acid or fumaric acid; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylic acid Ethylene-unsaturated monomers having a hydroxyl group such as 2-hydroxyhexyl ester may be used alone or in combination of two or more.

Among the monomers exemplified above, the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms has a considerable influence on the storage elastic modulus G' and the melting point. When a (meth) acrylate having a linear carbon group having a low carbon number among the (meth) acrylate is used in a large amount, the storage elastic modulus G′ and the melting point tend to be the specific values described above. . Specifically, it is preferred to use a (meth) acrylate having a linear alkyl group having 16 to 18 carbon atoms in a proportion of 30 parts by weight or more, preferably 30 to 40 parts by weight. Specific examples include copolymerization of 5 to 15 parts by weight of behenyl acrylate, 30 to 40 parts by weight of stearyl acrylate, 45 to 55 parts by weight of methyl acrylate, and 0 to 10 parts by weight of acrylic acid. Things and so on.

Further, in the (meth) acrylate having an alkyl group having 1 to 6 carbon atoms, when butyl acrylate is used, the storage elastic modulus G' and the melting point tend to be the specific values described above. Specific examples thereof include a copolymer obtained by polymerizing 40 to 50 parts by weight of behenyl acrylate, 45 to 55 parts by weight of butyl acrylate, and 0 to 10 parts by weight of acrylic acid.

The polymerization method is not particularly limited, and examples thereof include a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and an emulsion polymerization method. For example, when the solution polymerization method is employed, the monomer exemplified above may be mixed with a solvent and stirred at about 40 to 90 ° C for about 2 to 10 hours to polymerize the monomer.

The weight average molecular weight of the side chain crystalline polymer is preferably 5,000 or more, more preferably 5,000 to 900,000. If the weight average molecular weight is too small or too large, the storage elastic modulus G' and the melting point may deviate from the above-mentioned specific values. In addition, when the weight average molecular weight is too small, the cohesive force is lowered and the fixing power is lowered. If the weight average molecular weight is too large, the side chain crystalline polymer is hard to be displayed even if the pressure-sensitive adhesive sheet has a temperature equal to or higher than the melting point. The shackles of liquidity. The weight average molecular weight is a value obtained by measuring a side chain crystalline polymer by gel permeation chromatography (GPC) and converting the obtained measured value into polystyrene.

The thickness of the aforementioned adhesive sheet is preferably 15 to 400 μm, more preferably 120 to 150 μm. If the thickness of the above-mentioned adhesive sheet is too thin, the fixing force is lowered, and it is also difficult to function as a cushioning material, which is not preferable. Further, if the thickness of the adhesive sheet is too thick, it is difficult to prepare an adhesive sheet having a uniform thickness, which is not preferable.

It is preferable to provide a film which is subjected to release treatment, that is, a release film, on both sides of the adhesive sheet. The release film may be, for example, a release coating agent such as a silicone on the surface of a film made of polyethylene terephthalate or the like. When a release film is provided on both surfaces of the adhesive sheet, for example, a coating liquid in which a side chain crystalline polymer is added to a solvent is applied onto the release film and dried to obtain an adhesive sheet, and the adhesive sheet is obtained thereon. The surface is provided with a release film.

Various additives such as a crosslinking agent, a tackifier, a plasticizer, an anti-aging agent, and an ultraviolet absorber may be added to the coating liquid. The above coating can be generally carried out by a knife coater, a roll coater, a carriage coater, a comma coater or the like. Further, depending on the coating thickness and the viscosity of the coating liquid, it may be carried out by a gravure coater, a rod coater or the like. Further, the pressure-sensitive adhesive sheet may be formed into a sheet shape by, for example, extrusion molding or calendering, in addition to the above coating.

<Adhesive tape for mold fixing>

The adhesive tape for mold fixing of the present invention (hereinafter sometimes referred to as "adhesive tape") is formed by providing an adhesive layer on both surfaces of a base film, and at least the adhesive layer on the mold side is fixed by the mold of the present invention described above. Made of adhesive sheets. Thereby, the same effect as the above-mentioned adhesive sheet can be obtained, and since the base film is contained, the effect of being higher in rigidity than the adhesive sheet and more excellent in handleability can be obtained.

The foregoing substrate film may, for example, be polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamine, polyimine, polycarbonate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid B. A synthetic resin film such as an ester copolymer, an ethylene-polypropylene copolymer, or a polyvinyl chloride.

The base film may be composed of a single layer or a laminate, and has a thickness of usually about 25 to 250 μm. In order to improve the adhesion to the adhesive layer, the surface of the base film may be subjected to surface treatment such as corona treatment, plasma treatment, sand blasting, chemical etching treatment, primer treatment or the like.

When an adhesive layer is provided on one surface of the base film on the mold side, a coating liquid in which the side chain crystalline polymer is added to a solvent is applied to one side of the base film and dried. . The thickness of the adhesive layer is preferably 5 to 60 μm, more preferably 10 to 60 μm, still more preferably 10 to 40 μm.

The adhesive layer on the other side is not particularly limited, and for example, it may be composed of the above-described adhesive sheet for mold fixing of the present invention, similarly to the adhesive layer of one side. In this case, the side chain crystalline polymer of the one-sided adhesive layer and the side chain crystalline polymer of the other adhesive layer may have the same composition or different compositions.

Further, an adhesive layer containing a pressure-sensitive adhesive may be used as the adhesive layer on the other side. The pressure-sensitive adhesive is an adhesive polymer such as a natural rubber adhesive, a synthetic rubber adhesive, a styrene/butadiene latex adhesive, an acrylic adhesive, or the like. The thickness of the adhesive layer on one side and the thickness of the adhesive layer on the other side may be the same thickness or different thicknesses.

<Manufacturing method of fine structure>

In the first embodiment of the method for producing a fine structure of the present invention, the use of the mold fixing adhesive sheet of the present invention for fixing the mold and using the UV curable resin composition as the curable resin composition is exemplified. As an example, it will be described in detail with reference to FIG.

As shown in Fig. 1(a), first, the above-described mold fixing adhesive sheet 1 of the present invention is placed between the mold 10 and the pedestal 15. Examples of the material constituting the mold 10 include ruthenium, polyfluorene oxide, ruthenium dioxide (SiO ₂ ) glass, nickel, and polyethylene terephthalate. A predetermined fine pattern 11 is formed on the surface 10a of the mold 10. The fine pattern 11 is preferably in the order of nanometer (nm) to micrometer (μm). The thickness of the mold 10 is preferably about 10 to 2,000 μm. The thickness of the mold 10 means the thickness at which the distance between the surface 10a and the back surface 10b becomes maximum.

The material constituting the pedestal 15 may, for example, be cerium oxide glass or the like. The pedestal 15 is a system that stably supports the mold 10, and its thickness is preferably, for example, 1 to 2 mm.

After the adhesive sheet 1 is placed between the mold 10 and the pedestal 15, the mold 10 is fixed to the pedestal 15 via the adhesive sheet 1. The fixing is performed by setting the temperature of the sinter-adhesive sheet 1 to a temperature higher than a melting point of the side chain crystalline polymer, preferably a temperature of +10° C. or more, and then making the temperature not reach the melting point. Preferably, it is carried out at a temperature of -10 ° C or lower.

When such a specific temperature change occurs, the side chain crystalline polymer changes from a flowing state to a crystalline state, whereby the anchoring effect is exhibited for the reason described above, so that the surface smoothness can be ensured. The mold 10 is fixed to the pedestal 15 with a high fixing force. The temperature adjustment of the adhesive sheet 1 can be performed by adjusting the ambient temperature and the temperature of the pedestal 15 by using temperature adjustment means such as a gas, a fan, or a heater.

On the other hand, as shown in FIG. 1(b), the film 21 is formed on the surface of the substrate 20. Examples of the material constituting the substrate 20 include ruthenium and ruthenium dioxide glasses, and examples thereof include polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, and polyimide. A synthetic resin such as polycarbonate, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-polypropylene copolymer, or polyvinyl chloride. The thickness of the substrate 20 is preferably 50 to 300 μm, more preferably 100 to 150 μm. The substrate 20 is preferably made flexible.

The film 21 is composed of a UV curable resin composition. The UV curable resin composition is cured by irradiation with UV (ultraviolet rays), and various conventional materials can be used. The film 21 is formed by, for example, adding a UV curable resin composition to a predetermined solvent to obtain a coating liquid, and applying the coating liquid onto the surface of the substrate 20 and drying it. The coating can be carried out, for example, by a spin coating method, a slit coating method, a spray coating method, a roll coating method, or the like. The thickness of the uncured film 21 is preferably 0.01 to 1000 μm, more preferably 0.01 to 500 μm.

After the film 21 is formed on the surface of the substrate 20, the mold 10 is placed above the film 21. This arrangement is performed such that the fine pattern 11 of the mold 10 and the film 21 face each other. Next, the mold 10 is moved together with the pedestal 15 in the direction of the arrow A, and as shown in Fig. 1(c), the surface of the film 21 is pressed by the mold 10. Thereby, the fine pattern of the mold 10 is transferred to the film 21.

The pressurization conditions are about 0.1 to 100 MPa and the pressurization time is about 5 to 300 seconds. The curing of the film 21 by the transfer of the fine pattern 11 is performed by irradiating the film 21 with UV in a state where the surface of the film 21 is pressed by the mold 10, that is, in the state shown in Fig. 1(c).

The UV irradiation direction is not particularly limited as long as it can illuminate the film 21 with UV. In other words, when the substrate 20 has UV transparency, the film 21 may be irradiated with UV from the back side of the substrate 20. Further, the adhesive sheet 1 is usually UV-permeable. Therefore, when the pedestal 15 and the mold 10 are made of a material having UV permeability, the film 21 can be irradiated with UV from the back side of the pedestal 15 via the pedestal 15, the adhesive sheet 1, and the mold 10.

Next, as shown in FIG. 1(d), the mold 10 is moved together with the pedestal 15 in the direction of the arrow B, and the mold 10 is peeled off from the cured film 22. This peeling is usually performed by vertical peeling in order to suppress damage of the hardened film 22. When this vertical peeling is performed, a large load is applied to the adhesive sheet 1. Since the adhesive sheet 1 fixes the mold 10 with a high fixing force for the above reasons, even if the load is applied, the falling of the mold 10 can be suppressed.

When the mold 10 is peeled off from the cured film 22, the fine structure 25 composed of the cured film 22 of the transferred fine pattern 11 and the substrate 20 can be obtained. The thickness of the hardened film 22 is preferably 0.01 to 1000 μm, more preferably 0.01 to 500 μm.

The obtained fine structure 25 can be removed by, for example, oxygen reactive ion etching, and the surface of the substrate 20 is exposed from the adjacent hardened films 22 and 22, and then the cured film 22 is used as a mask. The cover is subjected to etching treatment, or aluminum or the like is lifted and used for use in wiring or the like. Further, when the novel fine structure 25 is continuously manufactured, the above steps may be repeated.

On the other hand, when the mold 10 is broken or when other fine structures having different fine patterns are produced, it is necessary to remove the mold 10 from the pedestal 15 and replace it with another mold. In this case, the pressure-sensitive adhesive sheet 1 may be heated to a temperature equal to or higher than the melting point of the side chain crystalline polymer by the temperature adjustment means. Thereby, since the side chain crystalline polymer exhibits fluidity, the fixing force of the adhesive sheet 1 is lowered, so that the mold 10 can be easily removed. The adhesive sheet 1 can be reused many times by performing the same operation as described above.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the invention. For example, in the embodiment of the manufacturing method of the fine structure described above, the case of using the mold fixing adhesive sheet of the present invention to produce a fine structure is described. However, the fine structure may be used by using the mold fixing adhesive tape of the present invention. It is manufactured by replacing the aforementioned adhesive sheet. At this time, the adhesive tape is attached to the pedestal via the adhesive layer on the other side so that the adhesive layer containing the one side of the side chain crystalline polymer faces the mold side.

In the above-described embodiment, a UV curable resin composition is used as the curable resin composition. However, as the other curable resin composition, for example, polymethyl methacrylate (PMMA) may be used. ) a thermoplastic resin composition. In the above-described embodiment, the case where the film of the transferred fine pattern is cured while being pressed by the mold is described. However, the curing of the film may be performed after the mold is peeled off.

Hereinafter, the present invention will be described in detail by way of Synthesis Examples and Examples, but the present invention is not limited to the following Synthesis Examples and Examples. In the following description, "parts" means parts by weight.

(Synthesis Example 1)

First, 45 parts of behenyl acrylate, 50 parts of butyl acrylate, and 5 parts of acrylic acid, PERBUTYL ND (manufactured by NOF Corporation) as a polymerization initiator, and as a chain transfer agent A mixture of 6 parts of an alkyl mercaptan (n-dodecylmercaptan) (Japanese fat) was stirred at 80 ° C for 4 hours to polymerize the monomers. The resulting copolymer had a weight average molecular weight of 7,000 and a melting point of 37 °C. Further, the storage elastic modulus G' at the above melting point + 10 ° C was 3 × 10 ² Pa, and the storage elastic modulus G' at the melting point - 10 ° C was 5 × 10 ⁶ Pa.

(Synthesis Example 2)

First, 45 parts of behenyl acrylate, 50 parts of butyl acrylate, 5 parts of acrylic acid, and PERBUTYL ND (manufactured by NOF Corporation) as a polymerization initiator were mixed at a ratio of 0.5 parts at 55 ° C. hour. Next, after raising the temperature to 80 ° C, 0.5 part of PERHEXYL PV (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator was added and stirred for 2 hours to polymerize the monomers. The obtained copolymer had a weight average molecular weight of 670,000 and a melting point of 46 °C. Further, the storage elastic modulus G' at the above melting point + 10 ° C was 7 × 10 ³ Pa, and the storage elastic modulus G' at the melting point - 10 ° C was 1 × 10 ⁶ Pa.

(Synthesis Example 3)

First, it is mixed with 15 parts of icosyl acrylate, 30 parts of stearyl acrylate, 50 parts of methyl acrylate, 5 parts of acrylic acid, and PERBUTYL ND (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator. And stirred at 55 ° C for 4 hours. Next, after raising the temperature to 80 ° C, 0.5 part of PERHEXYL PV (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator was added and stirred for 2 hours to polymerize the monomers. The obtained copolymer had a weight average molecular weight of 650,000 and a melting point of 41 °C. Further, the storage elastic modulus G' at the above melting point + 10 ° C was 8 × 10 ⁴ Pa, and the storage elastic modulus G' at the melting point - 10 ° C was 2 × 10 ⁷ Pa.

(Comparative Synthesis Example 1)

First, PERBUTYL ND (manufactured by NOF Corporation) of 0.5 parts of 20 parts of behenyl acrylate, 25 parts of stearyl acrylate, 50 parts of methyl acrylate, and 5 parts of acrylic acid as a polymerization initiator, and as The chain transfer agent was mixed in a ratio of 6 parts of n-dodecyl mercaptan (Japanese fat) and stirred at 80 ° C for 4 hours to polymerize the monomers. The resulting copolymer had a weight average molecular weight of 7,000 and a melting point of 40 °C. Further, the storage elastic modulus G' at the above melting point + 10 ° C was 5 × 10 ¹ Pa, and the storage elastic modulus G' at the melting point - 10 ° C was 5 × 10 ⁷ Pa.

(Comparative Synthesis Example 2)

First, it is mixed with 65 parts of behenyl methacrylate, 30 parts of butyl methacrylate, 5 parts of methacrylic acid, and 0.5 parts of PERBUTYL ND (manufactured by NOF Corporation) as a polymerization initiator. It was stirred at 55 ° C for 4 hours. Next, after raising the temperature to 80 ° C, 0.5 part of PERHEXYL PV (manufactured by Nippon Oil Co., Ltd.) as a polymerization initiator was added and stirred for 2 hours to polymerize the monomers. The resulting copolymer had a weight average molecular weight of 250,000 and a melting point of 35 °C. Further, the storage elastic modulus G' at the above melting point + 10 ° C was 5 × 10 ⁵ Pa, and the storage elastic modulus G' at the melting point - 10 ° C was 9 × 10 ⁵ Pa.

The copolymers of the above Synthesis Examples 1 to 3 and Comparative Synthesis Examples 1 and 2 are shown in Table 1. In addition, the weight average molecular weight is a value obtained by measuring a copolymer by GPC and converting the obtained measured value into polystyrene. The above melting point was measured using DSC under the measurement conditions of 10 ° C / min. The storage elastic modulus G' was measured using a dynamic viscoelasticity measuring device "DMS 6100" manufactured by Seiko Instruments Inc. at a temperature of 10 Hz, 5 ° C / min, and -100 to 400 ° C at a melting point of ± 10 ° C. The value obtained by storing the elastic modulus G'.

As is apparent from Table 1, in the synthesis examples 1 and 2, the storage elastic modulus G' and the melting point were controlled to the specific values described above by using butyl acrylate as a main component. Further, in Synthesis Example 3, the stearyl acrylate having a lower carbon number among the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms was prepared in a ratio of 30 parts by weight, and was stored. The elastic modulus G' and the melting point are controlled at the aforementioned specific values.

(Examples 1 to 3 and Comparative Examples 1, 2) <Production of Adhesive Sheets>

First, each of the copolymers obtained in the above Synthesis Examples 1 to 3 and Comparative Synthesis Examples 1 and 2 was adjusted to a solid content of 30% using ethyl acetate to obtain each copolymer solution. Next, an adhesive solution was prepared by adding an isocyanate crosslinking agent in an amount of 0.5 part by weight to 100 parts of each of the copolymer solutions, and the adhesive solution was applied to a polyethylene terephthalate having a thickness of 100 μm. One side of the ester film (PET film) was dried and an adhesive tape having an adhesive layer having a thickness of 40 μm was formed.

<evaluation>

For each of the adhesive tapes obtained above, the vertical peel strength was evaluated. The evaluation method is as follows, and the results are shown in Table 2.

[Vertical peel strength]

First, the above adhesive tape was fixed to a plate made of an acrylic resin. In this fixing, the other side of the PET film opposite to the one surface on which the adhesive layer is formed is attached to the platen by using an acrylic adhesive ("AS5020" manufactured by Yoshiko Oils Co., Ltd.). get on. Thereby, the adhesive layer is placed upward with respect to the platen.

Then, a positive cube made of stainless steel (SUS) having a length of 10 mm was adhered to the above-mentioned adhesive layer under the following conditions and pressed at 2 kg for 5 seconds, and then the positive cube was perpendicularly formed from the aforementioned adhesive layer at a speed of 300 mm/min. Stripped. The vertical peel strength at this time was measured by a load cell.

(60 ° C)

The positive cube was adhered to the pressure-sensitive adhesive layer at an ambient temperature of 60 ° C and pressurized, and then peeled off vertically.

(60 ° C → 23 ° C)

After the positive cube and the aforementioned adhesive layer were adhered and pressurized at an ambient temperature of 60 ° C, the ambient temperature was lowered to 23 ° C, and after standing at this ambient temperature for 20 minutes, it was peeled off vertically.

As is apparent from Table 2, in terms of the vertical peel strength at 60 → 23 ° C, Examples 1 to 3 exhibited very high fixing forces as compared with Comparative Examples 1 and 2. Further, as a result of the vertical peel strength of 60 ° C, it was found that the examples 1 to 3 can be easily removed by heating to a temperature higher than the melting point.

1. . . Mold fixing adhesive sheet

10. . . Mold

10a. . . Mold surface

10b. . . The back of the mold

11. . . Fine pattern

15. . . Pedestal

20. . . Substrate

twenty one. . . Film

twenty two. . . Hardened film

25. . . Microstructure

26. . . Residual film

Fig. 1 (a) to (d) are process diagrams showing an embodiment in which a fine structure is produced by using the adhesive sheet for mold fixing of the present invention.

1. . . Mold fixing adhesive sheet

10. . . Mold

10a. . . Mold surface

10b. . . The back of the mold

11. . . Fine pattern

15. . . Pedestal

20. . . Substrate

twenty one. . . Film

twenty two. . . Hardened film

25. . . Microstructure

26. . . Residual film

Claims (8)

An adhesive sheet for mold fixing, which comprises a side chain crystalline polymer as a main component, and the side chain crystalline polymer is a (meth) acrylate 20 having a linear alkyl group having 16 to 22 carbon atoms. a polymer obtained by polymerizing 0 to 70 parts by weight of a (meth) acrylate having an alkyl group having 1 to 6 carbon atoms, and 0 to 10 parts by weight of a polar monomer, the aforementioned side chain crystalline polymer The melting point is 30 to 70 ° C, and crystallizes at a temperature not reaching the melting point, and exhibits fluidity at a temperature above the melting point, and the storage elastic modulus G' at the above melting point + 10 ° C is 1 × In the case of 10 ² to 1 × 10 ⁵ Pa, the storage elastic modulus G' at the above-mentioned melting point -10 ° C is 1 × 10 ⁵ to 1 × 10 ⁹ Pa. The adhesive sheet for mold fixing according to the first aspect of the invention, wherein the side chain crystalline polymer is 5 to 15 parts by weight of behenyl acrylate, 30 to 40 parts by weight of stearyl acrylate, and methyl acrylate. A copolymer obtained by polymerizing 45 to 55 parts by weight, and 0 to 10 parts by weight of acrylic acid. The adhesive sheet for mold fixing according to the first aspect of the invention, wherein the side chain crystalline polymer is 40 to 50 parts by weight of behenyl acrylate, 45 to 55 parts by weight of butyl acrylate, and 0 to 5,000 acrylate. 10 parts by weight of the copolymer obtained by polymerization. An adhesive tape for fixing a mold, which is formed by providing an adhesive layer on both sides of a base film, and at least the adhesive layer on the mold side is applied for a patent It is composed of the adhesive sheet for fixing the mold of the first item. A method for manufacturing a fine structure, which is a method for producing a fine structure by using an adhesive sheet for mold fixing according to the first aspect of the patent application, comprising the steps of: interposing the adhesive sheet between a mold and a pedestal; After the temperature of the adhesive sheet is higher than the melting point of the side chain crystalline polymer, the temperature is set to a temperature that does not reach the melting point, and the mold is fixed to the pedestal via the adhesive sheet; The step of pressurizing the surface of the film formed of the curable resin composition to transfer the fine pattern of the mold; and the step of curing the film of the transferred fine pattern to obtain a fine structure. The method for producing a fine structure according to the fifth aspect of the invention, wherein the temperature of the adhesive sheet is at a temperature of +10 ° C or more after the melting point of the side chain crystalline polymer, and the temperature becomes the melting point -10 The temperature below °C, and the mold is fixed to the pedestal via the adhesive sheet. The method for producing a fine structure according to the fifth aspect of the invention, wherein the curable resin composition is composed of a UV curable resin composition, and a film composed of the UV curable resin composition is formed by a mold. After the surface is pressed, the fine pattern is transferred, and after the UV is irradiated to cure the film, the mold is vertically peeled off from the cured film. The manufacturing method of the fine structure of the fifth aspect of the invention, wherein the fine pattern of the mold is in the range of nanometers (nm) to micrometers (μm).