JP5698958B2 - Method for producing imprint mold - Google Patents

Description

  The present invention relates to an imprint mold, a method for producing the same, and a method for producing a fine structure.

  Recently, imprint lithography capable of forming a fine pattern with high throughput has attracted attention. Imprint lithography forms a film made of a curable resin composition on the surface of a substrate, presses the film surface with a mold, transfers the fine pattern of the mold to the film surface, and cures the film to which the fine pattern has been transferred. Thus, a fine pattern is formed on the substrate surface.

  Since the fine pattern formed by imprint lithography corresponds to the fine pattern of the mold to be used, the importance of the mold in imprint lithography is high. In order to prevent the resin composition from adhering, the mold fine pattern is usually subjected to a mold release treatment using a fluorine-containing self-assembled monolayer or the like.

  However, when imprint lithography is repeatedly performed, there has been a problem that the mold release process applied to the fine pattern deteriorates (for example, see Non-Patent Document 1). When imprint lithography is performed using a mold whose mold release process has deteriorated, not only the transfer accuracy is lowered, but the mold itself is also damaged.

  When a re-molding process is performed on the fine pattern of the mold, high throughput, which is one of the features of imprint lithography, is impaired. The fine pattern of the mold is usually formed by electron beam (EB) lithography. In EB lithography, the more complex the pattern is, the more time it takes to form it. Therefore, if the mold is damaged, it cannot be easily reproduced. Therefore, there has been a demand for the development of a mold that can be easily reproduced without the need for a mold release process or a remolding process. The mold is also required to be excellent in the shape retention of a fine pattern in order to maintain the transfer accuracy.

Y.Tada, H.Yoshida, and A.Miyauchi, J.Photopolym.Sci.Technol., 20, p545,2007

  An object of the present invention is to provide an imprint mold having a high releasability and easily reproducible and having excellent shape retention of a fine pattern, a method for producing the same, and a method for producing a fine structure. That is.

  As a result of intensive studies to solve the above problems, the present inventors have found the following findings. That is, the present applicant has previously developed a side chain crystalline polymer as described in JP-A-9-251923. The side chain crystalline polymer is a polymer that reversibly causes a crystalline state and a fluidized state in response to a temperature change. As described in JP-A-9-251923, the adhesive layer of an adhesive tape is usually used. Used for.

As a result of repeated studies on this side chain crystalline polymer, the present inventors have found the following new findings.
(I) The side chain crystalline polymer in a crystalline state is excellent in releasability.
(Ii) Thermal imprinting on the side chain crystalline polymer can be performed at a relatively low temperature, and can be performed efficiently in a short time.

  Therefore, if a master type fine pattern is thermally imprinted on the side chain crystalline polymer, a mold in which the master type fine pattern is efficiently transferred in a short time can be obtained. Further, since the fine pattern of the mold is made of a side chain crystalline polymer having excellent releasability, it is not necessary to perform a release treatment or a re-release treatment on the fine pattern of the mold. Moreover, the mold can be easily reproduced by repeatedly using the master mold.

On the other hand, an ultraviolet curable resin composition is often employed as a curable resin composition that forms a film to which a fine pattern of a mold is transferred. Imprint lithography for the ultraviolet curable resin composition is usually performed as follows.
(I) First, the surface of the film made of the ultraviolet curable resin composition is pressurized with the mold, and the fine pattern of the mold is transferred to the surface of the film.
(II) Next, ultraviolet rays are irradiated to cure the film having the fine pattern transferred to the surface, and then the mold is removed from the cured film to obtain a fine structure.

  Here, in the step (II), when the ultraviolet curable resin composition is cured by irradiating with ultraviolet rays, heat is generated. However, the shape of the fine pattern made of the side chain crystalline polymer tends to collapse due to this heat. was there.

  The present inventors have further studied based on these findings described above. As a result, the heat resistance of the side chain crystalline polymer can be improved by introducing an ultraviolet curable functional group into the side chain crystalline polymer and curing the polymer, and as a result, it occurs in imprint lithography. It has been found that the shape of the fine pattern can be prevented from collapsing by heat, and that the above problems can be solved, and the present invention has been completed.

That is, this invention consists of the following structures.
(1) An ultraviolet curable side chain comprising a surface layer having a fine pattern on its surface and a support layer for supporting a back surface opposite to the surface of the surface layer, wherein the surface layer has an ultraviolet curable functional group. An imprint mold comprising a crystalline polymer.
(2) The mold for imprint according to (1), wherein the ultraviolet curable side chain crystalline polymer is obtained by reacting a side chain crystalline polymer with a compound having an ultraviolet curable functional group.
(3) The mold for imprints according to (1) or (2), wherein the ultraviolet curable functional group is a (meth) acryloyloxy group.
(4) The ultraviolet curable side chain crystalline polymer is crystallized at a temperature lower than the melting point, and exhibits fluidity at a temperature equal to or higher than the melting point, for imprinting according to any one of (1) to (3) mold.
(5) The mold for imprints according to any one of (1) to (4), wherein a release treatment is not performed on the fine pattern.
(6) The mold for imprints according to any one of (1) to (5), wherein the fine pattern is on a nano to micrometer scale.

(7) A first step of laminating a surface layer made of an ultraviolet curable side chain crystalline polymer having an ultraviolet curable functional group on the support layer, and the surface of the surface layer in a master mold having a fine pattern, A second step of pressurizing at a temperature equal to or higher than the melting point of the ultraviolet curable side chain crystalline polymer, and then setting the temperature of the surface layer to a temperature lower than the melting point of the ultraviolet curable side chain crystalline polymer. After crystallizing the functional polymer, peeling the master mold from the surface of the surface layer, and transferring the fine pattern of the master mold to the surface of the surface layer, and after the second process, Or after the said 3rd process, an ultraviolet-ray is irradiated and the said ultraviolet curing type side chain crystalline polymer is hardened, The manufacturing method of the mold for imprint characterized by the above-mentioned.
(8) The method for producing an imprint mold according to (7), wherein the ultraviolet curable side chain crystalline polymer is cured by irradiating ultraviolet rays after the second step.
(9) The method for producing an imprint mold according to (7) or (8), wherein a release process is not performed on the fine pattern of the master mold.

(10) A method for producing a microstructure using the imprint mold according to any one of (1) to (6) above, wherein the film made of a curable resin composition is formed with the imprint mold. Pressurizing the surface, transferring the fine pattern of the imprint mold to the surface of the film, curing the film having the fine pattern transferred to the surface, and then peeling the imprint mold from the cured film And a step of obtaining a fine structure.
(11) The curable resin composition is composed of an ultraviolet curable resin composition, and the surface of the film made of the ultraviolet curable resin composition is pressed with the imprint mold to transfer the fine pattern onto the surface of the film. Then, the method for producing a fine structure according to (10), wherein the film having the fine pattern transferred onto the surface is cured by irradiating ultraviolet rays.

  Since the ultraviolet curable side chain crystalline polymer according to the present invention is excellent in releasability in a crystalline state, a mold pattern made of the ultraviolet curable side chain crystalline polymer has a release treatment or a rerelease treatment. Therefore, high throughput of imprint lithography is not impaired. In addition, since UV curable side-chain crystalline polymer can be thermally imprinted at a relatively low temperature, a master-type fine pattern can be efficiently heat-imprinted in a short time to form a mold fine pattern. . In addition, the mold can be easily reproduced by repeatedly using the master mold.

  Furthermore, since the ultraviolet curable side chain crystalline polymer has an ultraviolet curable functional group, it can be cured by ultraviolet rays to improve heat resistance. Therefore, the heat generated by imprint lithography can reduce the mold fineness. It can suppress that the shape of a pattern collapses.

It is a schematic side view which shows one Embodiment concerning the mold for imprint of this invention. (A)-(d) is process drawing which shows the manufacturing method of the mold for imprint shown in FIG. (A)-(d) is process drawing which shows one Embodiment which manufactures a microstructure using the mold for imprint shown in FIG.

<Imprint mold>
Hereinafter, an embodiment of the imprint mold of the present invention will be described in detail with reference to FIG. As shown in the figure, an imprint mold 10 according to this embodiment includes a surface layer 1 and a support layer 5.

  The surface layer 1 is made of a side chain crystalline polymer having an ultraviolet curable functional group, that is, an ultraviolet curable side chain crystalline polymer. The ultraviolet curable side chain crystalline polymer is a polymer that crystallizes at a temperature below the melting point and exhibits fluidity at a temperature above the melting point. That is, the ultraviolet curable side chain crystalline polymer reversibly causes a crystalline state and a fluid state in response to a temperature change.

  The surface layer 1 made of an ultraviolet curable side chain crystalline polymer has a fine pattern 2 formed on the surface 1a thereof, and the fine pattern 2 is also made of an ultraviolet curable side chain crystalline polymer. The ultraviolet curable side chain crystalline polymer in the crystalline state has a high releasability. Therefore, the fine pattern 2 also has a high releasability, and therefore it is not necessary to perform a conventional release treatment or re-release treatment on the fine pattern 2.

  Moreover, the ultraviolet curable functional group which an ultraviolet curable side chain crystalline polymer has is a functional group which hardens | cures by ultraviolet irradiation. Therefore, when the ultraviolet curable side chain crystalline polymer is irradiated with ultraviolet rays, it is cured and heat resistance is improved.

  The ultraviolet curable side chain crystalline polymer is obtained by reacting a side chain crystalline polymer with a compound having an ultraviolet curable functional group. Specifically, the side-chain crystalline polymer includes, for example, a (meth) acrylate having a linear alkyl group having 16 or more carbon atoms, a (meth) acrylate having an alkyl group having 1 to 6 carbon atoms, and hydroxy It consists of a copolymer obtained by polymerizing (meth) acrylate having an alkyl group.

  Examples of the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms include 16 to 16 carbon atoms such as cetyl (meth) acrylate, stearyl (meth) acrylate, eicosyl (meth) acrylate, and behenyl (meth) acrylate. (Meth) acrylate having 22 linear alkyl groups can be mentioned. Examples of the (meth) acrylate having 1 to 6 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) ) Acrylate, hexyl (meth) acrylate and the like, and these may be used alone or in combination of two or more.

  The (meth) acrylate having a hydroxyalkyl group reacts with a compound having an ultraviolet curable functional group, which will be described later. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Examples thereof include hydroxyhexyl (meth) acrylate, and these may be used alone or in combination of two or more.

  The polymerization rate of the side chain crystalline polymer is, for example, 20 to 99 parts by weight of the (meth) acrylate having a linear alkyl group having 16 or more carbon atoms and (meth) acrylate having an alkyl group having 1 to 6 carbon atoms. Is preferably 0 to 70 parts by weight and (meth) acrylate having a hydroxyalkyl group is 1 to 20 parts by weight.

  The polymerization method is not particularly limited, and for example, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method and the like can be employed. For example, when the solution polymerization method is employed, the monomer can be polymerized by mixing the monomer exemplified above in a solvent and stirring at about 40 to 90 ° C. for about 2 to 10 hours.

  The weight average molecular weight of the side chain crystalline polymer is preferably 100,000 or more, more preferably 400,000 to 800,000. If the weight average molecular weight is too small, the strength of the fine pattern 2 may be lowered and easily damaged. Moreover, when the said weight average molecular weight is too large, there exists a possibility that the reactivity with the compound which has an ultraviolet curable functional group may fall. 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 measurement value to polystyrene.

  On the other hand, in the compound having the ultraviolet curable functional group, examples of the ultraviolet curable functional group include a (meth) acryloyloxy group and a vinyl group, and a (meth) acryloyloxy group is preferable.

  As the compound having an ultraviolet curable functional group, an isocyanate compound is preferable in reacting with the (meth) acrylate having a hydroxyalkyl group of the side chain crystalline polymer. Examples of the isocyanate compound include 2-methacryloyloxyethyl isocyanate represented by the following formula (I), 2-acryloyloxyethyl isocyanate represented by the following formula (II), and the following formula (III). 1,1-bis (acryloyloxymethyl) ethyl isocyanate and the like are preferable.

  Examples of other isocyanate compounds other than the isocyanate compounds represented by the formulas (I) to (III) include 2- (meth) acryloyloxypropyl isocyanate, 2- (meth) acryloyloxybutyl isocyanate, ( And (meth) acryloyl isocyanate, 1- (4-vinylphenyl) -1-methylethyl isocyanate, and the like. These exemplified isocyanate compounds may be used alone or as a mixture.

  The reaction between the side chain crystalline polymer and the compound having an ultraviolet curable functional group is performed by mixing the side chain crystalline polymer and the compound at a predetermined ratio, and then in an inert gas atmosphere such as nitrogen gas, in an amount of 40-80. It is preferable to stir at about 1 ° C. for about 1 to 6 hours.

  The mixing ratio of the side chain crystalline polymer and the compound having an ultraviolet curable functional group is, for example, a ratio of 1 to 180 parts by weight of the compound having an ultraviolet curable functional group with respect to 100 parts by weight of the side chain crystalline polymer. The ratio is preferably 10 to 50 parts by weight. If the proportion of the side chain crystalline polymer is too small or the proportion of the compound is too large, crystallization is difficult even if the obtained ultraviolet curable side chain crystalline polymer is cooled to a temperature below the melting point. Further, when the proportion of the side chain crystalline polymer is too large or the proportion of the compound is too small, it becomes difficult to cure even when irradiated with ultraviolet rays.

  A photopolymerization initiator is used for curing the ultraviolet curable functional group. The photopolymerization initiator may be appropriately selected according to the composition of the ultraviolet curable functional group, and is not particularly limited. Moreover, the said photoinitiator can use a commercial item. Examples of commercially available photopolymerization initiators include “IRGACURE 184” and “IRGACURE 500” manufactured by Ciba Japan.

  As a weight average molecular weight of the ultraviolet curable side chain crystalline polymer obtained, 100,000 or more are preferable and 400,000-800,000 are more preferable. If the weight average molecular weight is too small, the strength of the fine pattern 2 may be lowered and easily damaged. On the other hand, if the weight average molecular weight is too large, even if the ultraviolet curable side chain crystalline polymer is heated to a temperature equal to or higher than the melting point, it becomes difficult to exhibit fluidity, so that thermal imprinting becomes difficult. The weight average molecular weight is a value obtained by measuring an ultraviolet curable side chain crystalline polymer by GPC and converting the obtained measurement value to polystyrene.

  Here, the melting point of the UV-curable side-chain crystalline polymer means a temperature at which a specific portion of the polymer originally aligned in an ordered arrangement becomes disordered by a certain equilibrium process, and is a differential thermal scanning. It is a value obtained by measuring with a calorimeter (DSC) under measurement conditions of 10 ° C./min.

  The mold 10 is used at a temperature below the melting point at which the ultraviolet curable side chain crystalline polymer is in a crystalline state. Therefore, the melting point is preferably 30 ° C. or higher, and more preferably 50 to 60 ° C. On the other hand, if the melting point is too low, the temperature range in which the mold 10 can be used becomes narrow, which is not preferable. The fine pattern 2 of the mold 10 is formed by thermal imprinting as will be described later. Therefore, if the melting point is too high, it is difficult to perform thermal imprinting, which is not preferable. The melting point can be arbitrarily set by changing the composition of the side chain crystalline polymer described above.

  In many cases, the melting point of the UV-curable side chain crystalline polymer does not change before and after UV irradiation. That is, the melting point of the UV curable side chain crystalline polymer after UV curing is often substantially the same as the melting point of the UV curable side chain crystalline polymer before UV curing.

  Further, the ultraviolet curable side chain crystalline polymer after ultraviolet curing is crystallized at a temperature lower than the melting point, and exhibits a fluidity by phase transition at a temperature higher than the melting point. That is, the ultraviolet curable side-chain crystalline polymer reversibly causes a crystalline state and a fluid state in response to a temperature change in any state before and after ultraviolet irradiation.

  Various types of additives such as an anti-aging agent and a crosslinking agent can be added to the ultraviolet curable side chain crystalline polymer. When a crosslinking agent is added, it is preferable to copolymerize a polar monomer with an ultraviolet curable side chain crystalline polymer as a crosslinking component that undergoes a crosslinking reaction with the crosslinking agent. Examples of the polar monomer include carboxyl group-containing ethylenically unsaturated monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid. These may be used alone or in combination of two or more. May be used.

  The thickness of the surface layer 1 made of the above-described ultraviolet curable side chain crystalline polymer is suitably about 0.01 to 1,000 μm. The thickness of the surface layer 1 means the thickness at which the distance between the surface 1a and the back surface 1b opposite to the surface 1a is the largest in the direction perpendicular to the surface 1a. The fine pattern 2 is preferably on a nano to micrometer scale. The shape of the fine pattern 2 is not particularly limited, and a desired one can be adopted.

On the other hand, the support layer 5 supports the back surface 1 b of the surface layer 1 and imparts rigidity to the mold 10. Examples of the material constituting the support layer 5 include silicon, silicone, and (SiO ₂ ) glass. The thickness of the support layer 5 is suitably about 10 to 1,000 μm.

  The surface 5a of the support layer 5 that supports the surface layer 1 is preferably subjected to a surface treatment. Thereby, the surface 5a is roughened and the adhesiveness of the support layer 5 and the surface layer 1 can be improved. Examples of the surface treatment include corona discharge treatment, plasma treatment, blast treatment, chemical etching treatment, and primer treatment.

  Here, the surface layer 1 made of an ultraviolet curable side chain crystalline polymer usually has ultraviolet transparency. When imprint lithography is performed on the ultraviolet curable resin composition, the support layer 5 is preferably made of a material having ultraviolet transparency. Thereby, since the mold 10 as a whole has ultraviolet transparency, the ultraviolet curable resin composition can be irradiated with ultraviolet rays through the mold 10.

<Method for producing imprint mold>
Next, an embodiment of a method for manufacturing the mold 10 will be described in detail with reference to FIG. As shown in FIG. 2A, first, the surface layer 1 made of an ultraviolet curable side chain crystalline polymer is laminated on the support layer 5 (first step). The surface 5a of the support layer 5 on which the surface layer 1 is laminated is preferably roughened by surface treatment in order to improve adhesion with the surface layer 1. The lamination is performed by applying a coating solution obtained by adding an ultraviolet curable side chain crystalline polymer to a solvent on the support layer 5 and drying it.

  The application can be generally performed by a knife coater, a roll coater, a calendar coater, a comma coater or the like. Further, depending on the coating thickness and the viscosity of the coating solution, a gravure coater, a rod coater, a spin coater or the like can be used.

  The surface layer 1 can be laminated by laminating the surface layer 1 formed into a sheet shape or a film shape by extrusion molding or calendering on the support layer 5 in addition to the above application.

After laminating the surface layer 1 on the support layer 5, as shown in FIG. 2 (b), the master mold 20 is disposed above the surface layer 1. The material constituting the master mold 20 is preferably a material having low affinity for the ultraviolet curable side chain crystalline polymer, and examples thereof include silicon, silicone, and (SiO ₂ ) glass. Further, in order to allow the surface layer 1 to be irradiated with ultraviolet rays through the master mold 20, it is preferable to employ a material having ultraviolet transparency as a material constituting the master mold 20.

  A fine pattern 21 is formed on the surface 20 a of the master mold 20 facing the surface 1 a of the surface layer 1. The reverse pattern of the fine pattern 21 becomes the fine pattern 2 of the mold 10. Therefore, the fine pattern 21 has a shape opposite to the desired fine pattern 2. The fine pattern 21 is preferably a nano to micrometer scale, and can be formed by EB lithography.

  The master mold 20 is moved in the direction of arrow A, and the surface 1a of the surface layer 1 is pressurized with the master mold 20 as shown in FIG. 2 (c) (second step). This pressurization is performed at a temperature equal to or higher than the melting point of the ultraviolet curable side chain crystalline polymer. Thereby, the ultraviolet curable side chain crystalline polymer becomes a fluid state, and thermal imprinting for transferring the fine pattern 21 of the master mold 20 to the surface 1a of the surface layer 1 becomes possible.

  The pressurizing temperature is preferably a temperature of the melting point + 10 ° C. to the melting point + 30 ° C. of the ultraviolet curable side chain crystalline polymer. As a result, the ultraviolet curable side-chain crystalline polymer is in an appropriate fluid state, the transfer accuracy by the master mold 20 is improved, and thermal imprinting at a relatively low temperature is achieved. On the other hand, when the pressurizing temperature is too low, the flow state of the ultraviolet curable side chain crystalline polymer is low, and the transfer accuracy by the master mold 20 may be lowered. On the other hand, if the pressurization temperature is too high, the ultraviolet curable side-chain crystalline polymer is heated more than necessary, which is economically disadvantageous because it requires a lot of heat energy.

  For adjusting the pressurizing temperature, for example, a heating means such as a heater is disposed on the back surface 20b opposite to the front surface 20a of the master mold 20, and the surface temperature of the fine pattern 21 is heated to a predetermined temperature by the heating means. The atmospheric temperature can be adjusted to a temperature equal to or higher than the melting point of the ultraviolet curable side chain crystalline polymer. As other pressurization conditions, a pressure of about 0.1 to 100 MPa and a pressurization time of about 5 to 300 seconds are preferable.

  Further, it is preferable to irradiate the surface layer 1 with ultraviolet rays while the surface 1 a of the surface layer 1 is pressurized with the master mold 20 to cure the ultraviolet curable side chain crystalline polymer that forms the surface layer 1. Thereby, the fine pattern 2 can be formed with high dimensional accuracy. The following reason is guessed as this reason. That is, as shown in FIG. 2 (c), when the surface layer 1 in a state where the surface 1a is pressed with the master mold 20 is irradiated with ultraviolet rays, the influence of curing shrinkage is reduced by the press of the master mold 20, Therefore, it is assumed that the fine pattern 2 can be formed with high dimensional accuracy.

  The ultraviolet irradiation direction is not particularly limited as long as the surface layer 1 can be irradiated with ultraviolet rays. That is, when the support layer 5 has ultraviolet transparency, the surface layer 1 may be irradiated with ultraviolet rays from the back surface 5 b side of the support layer 5. Further, when the master mold 20 is made of a material having ultraviolet transparency, the surface layer 1 may be irradiated with ultraviolet rays through the master mold 20. Other ultraviolet irradiation conditions are not particularly limited as long as the ultraviolet curable side chain crystalline polymer can be cured with ultraviolet rays.

  After the UV curable side chain crystalline polymer is UV cured, the surface layer 1 is cooled to a temperature below the melting point of the UV curable side chain crystalline polymer using a cooling means such as a fan. As a result, the ultraviolet curable side chain crystalline polymer enters a crystalline state.

  Then, as shown in FIG. 2 (d), the master mold 20 is moved in the direction of the arrow B, and the master mold 20 is peeled from the surface 1a of the surface layer 1 formed of the crystalline UV curable side chain crystalline polymer. (Third step). At this time, the ultraviolet curable side-chain crystalline polymer in a crystalline state has a high releasability as described above. Therefore, the master mold 20 can be peeled off from the surface layer 1 without performing the mold release process on the fine pattern 21 of the master mold 20, and productivity can be improved.

  When the master mold 20 is peeled off from the surface layer 1, the fine pattern 21 of the master mold 20 is transferred to the surface 1a of the surface layer 1, and the mold 10 having the fine pattern 2 opposite to the fine pattern 21 is obtained. Furthermore, if each process mentioned above is repeatedly performed using the master type | mold 20, the mold 10 can be reproduced easily.

  In the embodiment, the surface layer 1 is irradiated with ultraviolet rays while the surface 1a of the surface layer 1 is pressurized with the master die 20, and the ultraviolet curable side chain crystalline polymer forming the surface layer 1 is cured. Was described as an example. That is, in the above embodiment, the case where the step of irradiating ultraviolet rays to cure the ultraviolet curable side chain crystalline polymer is described as an example, but this step is performed after the third step, that is, the master. You may carry out after peeling the type | mold 20 from the surface layer 1. FIG.

<Microstructure manufacturing method>
Next, an embodiment in which a microstructure is manufactured using the mold 10 will be described in detail with reference to FIG. 3, taking as an example a case where an ultraviolet curable resin composition is used as the curable resin composition. As shown in FIG. 3A, first, a film 52 is formed on the surface of the substrate 51.

As a material constituting the substrate 51, for example, silicon, (SiO ₂ ) glass, etc., polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, Examples include synthetic resins such as ethylene polypropylene copolymer and polyvinyl chloride. The substrate 51 preferably has flexibility, and the thickness thereof is, for example, about 50 to 300 μm, preferably about 100 to 150 μm.

  The film 52 is made of an ultraviolet curable resin composition. The ultraviolet curable resin composition is cured by being irradiated with ultraviolet rays, and various known ones can be employed. For example, the coating film 52 may be formed by adding an ultraviolet curable resin composition to a predetermined solvent to obtain a coating solution, coating the coating solution on the surface of the substrate 51 and drying the coating solution. The application can be performed, for example, by spin coating, slit coating, spray coating, roller coating, or the like. The thickness of the uncured film 52 is, for example, about 0.01 to 1000 μm, preferably about 0.01 to 500 μm.

  After the film 52 is formed on the surface of the substrate 51, the mold 10 is disposed above the film 52 as shown in FIG. This arrangement is performed so that the fine pattern 2 of the mold 10 faces the coating 52. Next, the mold 10 is moved in the direction of arrow C, and the surface of the film 52 is pressurized with the mold 10 as shown in FIG. Thereby, the fine pattern 2 of the mold 10 is transferred to the film 52.

  As pressurization conditions, the pressure is about 0.1 to 100 MPa, and the pressurization time is about 5 to 300 seconds. The coating 52 to which the fine pattern 2 has been transferred is cured by irradiating the coating 52 in a state where the surface of the coating 52 is pressurized with the mold 10, that is, in the state shown in FIG. At this time, when the ultraviolet curable resin composition that forms the film 52 is cured by ultraviolet irradiation, heat is generated. However, the fine pattern 2 is composed of an ultraviolet curable side chain crystalline polymer that is ultraviolet cured and has excellent heat resistance. Therefore, the shape can be maintained.

  The ultraviolet irradiation direction is not particularly limited as long as the coating film 52 can be irradiated with ultraviolet rays. That is, when the substrate 51 has ultraviolet transparency, the coating film 52 may be irradiated with ultraviolet rays from the back side of the substrate 51. When the support layer 5 of the mold 10 is made of a material having ultraviolet transparency, the entire mold 10 has ultraviolet transparency as described above. Can be irradiated with ultraviolet rays.

  Next, as shown in FIG. 3 (d), the mold 10 is moved in the direction of arrow D to peel the mold 10 from the cured coating 53. At this time, the fine pattern 2 of the mold 10 is not subjected to the release treatment, but the fine pattern 2 has high releasability for the above-described reason, and therefore the hard coat 53 is applied when the mold 10 is peeled off. The load is small. Therefore, when the mold 10 is peeled from the cured film 53, the microstructure 50 composed of the cured film 53 to which the fine pattern 2 is transferred with dimensional accuracy and the substrate 51 is obtained. In addition, as thickness of the cured film 53, it is 0.01-1000 micrometers, for example, Preferably it is about 0.01-500 micrometers.

  In the obtained fine structure 50, the remaining film 54 is removed by, for example, oxygen reactive ion etching, and the surface of the substrate 51 is exposed between the adjacent cured films 53 and 53, and then the cured film 53 is used as a mask. Etching can be performed, or aluminum or the like can be lifted off and used for wiring or the like.

  In the above embodiment, the ultraviolet curable resin composition is described as an example of the curable resin composition. However, as another curable resin composition, for example, a thermoplastic resin composition such as polymethyl methacrylate (PMMA) is used. Things can also be used. Moreover, although the said embodiment demonstrated the case where hardening of the film | membrane with which the fine pattern was transcribe | transferred in the state pressurized by the mold, hardening of the said film | membrane can also be performed after peeling a mold.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to a following example.

  Production of the UV-curable side chain crystalline polymer used in the following Examples and the side chain crystalline polymer used in the Comparative Examples is as follows. In the following description, “part” means part by weight.

<Synthesis example>
First, 43 parts of behenyl acrylate, 47 parts of methyl acrylate, 10 parts of 2-hydroxyethyl acrylate, and perbutyl ND (manufactured by NOF Corporation) as a polymerization initiator were mixed at a ratio of 0.4 part, and these were mixed with acetic acid. The mixture was adjusted to a solid content of 30 parts with a mixed solvent of ethyl: heptane = 7: 3 (weight ratio) to obtain a mixed solution.

  Subsequently, this mixed liquid was stirred at 55 ° C. for 4 hours to polymerize these monomers to obtain a side chain crystalline polymer solution. The obtained side chain crystalline polymer had a weight average molecular weight of 550,000 and a melting point of 55 ° C. In addition, the said weight average molecular weight is a value which measured the side chain crystalline polymer by GPC, and converted the obtained measured value into polystyrene. The said melting | fusing point is the value which measured the side chain crystalline polymer on the measurement conditions of 10 degree-C / min by DSC.

  100 parts of the solution of the obtained side chain crystalline polymer in terms of solid content, 13 parts of 2-acryloyloxyethyl isocyanate represented by the formula (II) (“Karenz AOI” manufactured by Showa Denko KK) Part, 0.1 part of dibutylhydroxytoluene (BHT) as an antioxidant and 0.2 part of di-n-butyltin dilaurate (DBTDL) as a catalyst were mixed at a temperature of 60 ° C. in a nitrogen gas atmosphere. The mixture was stirred for 4 hours to obtain an ultraviolet curable side chain crystalline polymer solution. The obtained ultraviolet curable side chain crystalline polymer had a weight average molecular weight of 650,000 and a melting point of 55 ° C.

<Production of imprint mold>
As shown in FIG. 2, an imprint mold was produced. Each member used is as follows.
Surface layer: The ultraviolet curable side chain crystalline polymer obtained in the above synthesis example was used.
Support layer: 625 μm thick silicon was used. The surface of the support layer that supports the surface layer was dry-etched as a surface treatment. The dry etching process was performed with SF ₆ gas.
Master mold: A mold made of SiO ₂ glass having a fine pattern formed on the surface by EB lithography was used. The master-type fine pattern has a pattern dimension of 350 nm to 10 μm and a pattern depth of 350 nm. The master mold fine pattern was not subjected to mold release treatment.

The pressurizing conditions are as follows.
Pressurization temperature: 70 ° C. (melting point of UV curable side chain crystalline polymer + 15 ° C.)
Pressure: 5MPa
Pressurization time: 60 seconds In addition, adjustment of the said pressurization temperature is performed by arrange | positioning a heater in the back surface of a master type | mold, and heating so that the surface temperature of a master type | mold fine pattern may be set to 70 degreeC with this heater. It was.

  The mold was produced as follows. First, a surface layer was laminated on the support layer (see FIG. 2A). This lamination supports a coating solution in which 2.2 g of a photopolymerization initiator (“IRGACURE 500” manufactured by Ciba Japan Co., Ltd.) is added to 100 g of the ultraviolet curable side chain crystalline polymer solution obtained in the above synthesis example. The coating was performed on the layer with a spin coater and dried at an ambient temperature of 100 ° C. The thickness of the laminated surface layer was 1 μm.

Next, a master mold was placed above the surface layer (see FIG. 2B), and the surface of the surface layer was pressurized with the master mold under the pressure condition (see FIG. 2C). And the ultraviolet curing side chain crystalline polymer which forms a surface layer was hardened by irradiating with ultraviolet rays while maintaining the pressurized state by the master mold. Ultraviolet irradiation uses a high-power UV spot irradiation device “Toscure 251” manufactured by Harrison Toshiba Lighting Co., Ltd., and 400 mW / cm ² of ultraviolet rays emitted from the device is applied to the entire surface layer through a master mold. The irradiation was performed at room temperature (23 ° C.) for 6 seconds.

  Next, the temperature of the surface layer was cooled to room temperature (23 ° C.), which is a temperature lower than the melting point of the ultraviolet curable side chain crystalline polymer, using a fan. And the master type | mold was peeled from the surface of the surface layer, and the mold was obtained (refer FIG.2 (d)).

<Evaluation>
About the obtained mold, the shape retention of the fine pattern of the mold was evaluated. The evaluation method is shown below, and the results are shown in Table 1.

(Fine pattern shape retention)
First, the height of the fine pattern of the mold was measured with an atomic force microscope using a sensing lever. Next, after heat-treating the mold under the condition of exposure at 110 ° C. for 2 minutes, the height of the fine pattern was measured in the same manner as before the heat treatment. And the height of the fine pattern before and behind heat processing was applied to following formula (i), and shape retention (%) was computed.

[Comparative example]
First, in place of the UV-curable side-chain crystalline polymer solution, the side-chain crystalline polymer solution obtained in the above synthesis example was used, and a photopolymerization initiator was not added to this solution. Then, a surface layer having a thickness of 1 μm was laminated on the support layer.

  Next, the master mold was peeled off from the surface of the surface layer in the same manner as in the above example except that no ultraviolet irradiation was performed, and a mold was obtained. About the obtained mold, the shape retention of the fine pattern of the mold was evaluated in the same manner as in the above example. The results are shown in Table 1.

  As is apparent from Table 1, it can be seen that the example is superior in the shape retention of the fine pattern than the comparative example. Further, the fine pattern of the mold of the example was observed with a scanning electron microscope (magnification: 12,000 times). As a result, the reverse pattern of the master-type fine pattern was accurately transferred to the surface of the mold surface layer. Moreover, as a result of visually observing the master-type fine pattern after peeling, the ultraviolet curable side chain crystalline polymer was not adhered. From these results, it is understood that a fine mold pattern can be formed by thermally imprinting a master fine pattern on an ultraviolet curable side chain crystalline polymer. In addition, it can be said that the master-type fine pattern does not need to be subjected to a mold release process and is excellent in productivity. Furthermore, since the shape retention of the fine pattern is excellent, it is expected that if the mold of the example is used, imprint lithography can be performed without performing a mold release process on the fine pattern of the mold.

DESCRIPTION OF SYMBOLS 1 Surface layer 1a, 20a Surface 1b, 20b Back surface 2,21 Fine pattern 5 Support layer 10 Imprint mold 20 Master mold 50 Fine structure 51 Substrate 52 Film 53 Cured film 54 Residual film

Claims (3)

A first step of laminating a surface layer made of an ultraviolet curable side chain crystalline polymer having an ultraviolet curable functional group on a support layer;
A second step of pressurizing the surface of the surface layer with a master mold having a fine pattern at a temperature equal to or higher than the melting point of the ultraviolet curable side chain crystalline polymer;
Next, after the temperature of the surface layer is set to a temperature lower than the melting point of the ultraviolet curable side chain crystalline polymer to crystallize the ultraviolet curable side chain crystalline polymer, the master mold is peeled off from the surface of the surface layer. A third step of transferring the fine pattern of the mold to the surface of the surface layer,
After the second step or the third step, the ultraviolet curable side chain crystalline polymer is cured by irradiating with ultraviolet rays, and the imprint mold manufacturing method is characterized.   The method for producing an imprint mold according to claim 1, wherein the ultraviolet curable side chain crystalline polymer is cured by irradiating ultraviolet rays after the second step.   The method for producing an imprint mold according to claim 1, wherein a release process is not performed on the fine pattern of the master mold.

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