JP2015210497A - Fine pattern formation method, molding body, wire grid polarizer and transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine pattern formation method, molding body formed by the fine pattern formation method, wire grid polarizer, and transfer device that enhance a transfer property by limiting a wavelength required for hardening ultraviolet curable resin.SOLUTION: A fine pattern formation method is configured to: irradiate a surface of a stamper (50) including a fine pattern (52) having a release layer (55) with an ultraviolet ray in a state where a surface of ultraviolet curable resin (41) provided in a substrate (21) is pushed against the surface thereof to harden ultraviolet curable resin (41); transfer the fine pattern (52) on the surface; contain a photoinitiator whose light absorption wavelength is equal to or more than 380 nm in the ultraviolet curable resin (41); and has wavelength limiting means that limits an ultraviolet irradiation wavelength to the ultraviolet curable resin (41) to equal to or more than 380 nm.

Description

  The present invention relates to a fine pattern forming method for transferring a fine pattern onto a surface of an ultraviolet curable resin by a stamper, a molded body formed by the fine pattern forming method, a wire grid polarizer, and a transfer device.

  Conventionally, as a nanoimprint technology, there is a method in which an ultraviolet curable resin is applied on a transparent resin film, irradiated with ultraviolet rays while pressing a stamper having a fine pattern, and the fine pattern is transferred onto the surface of the ultraviolet curable resin. Are known. The ultraviolet curable resin contains a photopolymerization initiator, and photopolymerization is initiated by light absorption of the photopolymerization initiator to cure the ultraviolet curable resin. Thereafter, the ultraviolet curable resin having the fine pattern transferred to the surface is removed from the stamper.

  A molded body in which an ultraviolet curable resin is formed on a transparent resin film is used as a wire grid polarizer or the like in which a metal layer is formed on the surface of a fine pattern.

  By the way, from the viewpoint of the reproducibility of the shape of the fine pattern and the releasability of the stamper, a release layer made of fluorine or silicon is formed on the surface where the fine pattern is formed. The release layer is very thinly coated with a thickness equivalent to a monomolecular film of about several nm on the surface of the stamper.

  By interposing a release layer between the ultraviolet curable resin and the stamper, the cured ultraviolet curable resin can be easily removed from the stamper, and transfer can be performed repeatedly.

Japanese Patent No. 4981419 Japanese Patent No. 5209901 Japanese Patent No. 5264113

  However, conventionally, when the transfer is repeated, a part of the ultraviolet curable resin gradually remains on the stamper surface side, and the fine pattern formed on the surface of the ultraviolet curable resin becomes defective, and the number of times of transfer cannot be increased. There has occurred.

  It is considered that this is because the release layer receives strong energy having a short wavelength of the irradiation wavelength, so that the release layer is decomposed and the release effect is weakened. As a result, the transferability is lowered.

  The present invention has been made in view of such points, and is formed by a fine pattern forming method in which the wavelength necessary for curing an ultraviolet curable resin is limited to improve transferability, and the fine pattern forming method. A molded body, a wire grid polarizer, and a transfer device are provided.

  As a result of intensive studies, the present inventors have decided to limit the wavelength necessary for curing the ultraviolet curable resin. That is, in the present invention, the irradiation wavelength of a short wavelength of less than 380 nm is cut, and the ultraviolet curable resin is cured by the irradiation wavelength limited to 380 nm or more. Thereby, decomposition | disassembly of a mold release layer by the strong energy of a short wavelength can be suppressed, and it becomes possible to improve transferability. The present invention is specifically shown as follows.

  The present invention cures the ultraviolet curable resin by irradiating the surface of the stamper having a fine pattern provided with a release layer with the ultraviolet ray being pressed against the surface of the ultraviolet curable resin provided on the substrate. A method for forming a fine pattern by transferring the fine pattern to the surface, wherein the ultraviolet curable resin contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more, and ultraviolet rays to the ultraviolet curable resin. It has a wavelength limiting means which limits the irradiation wavelength of 380 nm or more.

  With this configuration, it is possible to limit the irradiation wavelength of the ultraviolet ray irradiated to the ultraviolet curable resin pressed against the stamper through the release layer to 380 nm or more, and to the ultraviolet curable resin, the light absorption wavelength is 380 nm or more. By including a polymerization initiator, the release layer provided on the stamper surface does not receive strong energy of a short wavelength as in the past, and the release layer can be decomposed even if the number of times of transfer is increased compared to the conventional case. Can be suppressed. Therefore, according to the fine pattern forming method of the present invention, defects in the fine pattern formed on the surface of the ultraviolet curable resin can be suppressed and the number of transfers can be increased as compared with the conventional method.

  In the present invention, as the wavelength limiting means, a light source limited to an irradiation wavelength of 380 nm or more can be used. For example, the light source is a single wavelength LED light source.

  Alternatively, in the present invention, as the wavelength limiting means, a band pass filter that limits the irradiation wavelength to 380 nm or more can be used in the middle of the light irradiation path from the light source to the ultraviolet curable resin.

  Alternatively, in the present invention, a transparent substrate that absorbs an irradiation wavelength of less than 380 nm is used as the wavelength limiting means, and the ultraviolet light can be irradiated from the transparent substrate side.

  Moreover, in this invention, it is preferable to make thickness of the said ultraviolet curable resin into the range of 0.5 micrometer or more and 5 micrometers or less.

  Moreover, the molded body in the present invention has a base material and an ultraviolet curable resin layer formed on the surface of the base material, and the surface of the ultraviolet curable resin layer is formed by the method described in any one of the above. A fine pattern is formed.

  The wire grid polarizer in the present invention is characterized in that a metal layer is formed on at least a part of the surface of the fine pattern of the molded body.

  Further, the present invention cures the ultraviolet curable resin by irradiating the surface of the stamper having a fine pattern provided with a release layer with the ultraviolet ray being pressed against the surface of the stamper. And a transfer device for transferring the fine pattern onto the surface, characterized by comprising wavelength limiting means for limiting an irradiation wavelength of ultraviolet rays to the ultraviolet curable resin to 380 nm or more.

  In the present invention, as the wavelength limiting means, a light source limited to an irradiation wavelength of 380 nm or more, or a bandpass filter that limits the irradiation wavelength to 380 nm or more in the middle of the light irradiation path from the light source to the ultraviolet curable resin. At least one of them can be used.

  According to the present invention, even when repetitive transfer is performed, decomposition of the release layer can be suppressed as compared with the conventional case, and therefore, the residual amount of resin on the stamper surface can be suppressed and transferability can be improved. Thereby, the productivity (yield) of the molded body and wire grid polarizer of the present invention can be improved.

FIG. 1A is a schematic cross-sectional view of a molded body according to the present embodiment, and FIG. 1B is a schematic plan view of the molded body. 2A is a schematic cross-sectional view of the wire grid polarizer according to the present embodiment, and FIG. 2B is a schematic plan view of the wire grid polarizer. 1 is a schematic view of a roll-to-roll type transfer apparatus according to the present embodiment. It is a partial expansion schematic diagram of the transfer hardening part of a transfer apparatus. It is a partial schematic diagram which shows the transfer hardening part of a transfer apparatus, and is a figure for demonstrating a 1st wavelength limiting means. It is a partial schematic diagram which shows the transfer hardening part of a transfer apparatus, and is a figure for demonstrating a 2nd wavelength limiting means. It is a partial schematic diagram which shows the transfer hardening part of a transfer apparatus, and is a figure for demonstrating a 3rd wavelength limitation means. FIG. 8A is a diagram showing a spectral distribution when a high-pressure UV lamp is used as the light source according to the present embodiment, and FIG. 8B shows a spectral distribution when a metal halide lamp is used as the light source according to the present embodiment. FIG. It is a graph which shows the relationship between the wavelength and the light transmittance in the base material from which material differs. It is a cross-sectional schematic diagram for demonstrating a batch type transfer method. FIG. 11A is a schematic plan view of transfer defects observed in the wire grid polarizer in the comparative example, and FIG. 11B is a schematic plan view of transfer defects observed in the wire grid polarizer in the present example.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  The present invention limits the wavelength of ultraviolet rays irradiated to cure the ultraviolet curable resin to a predetermined wavelength in the process of transferring a fine pattern onto the resin surface with the stamper pressed against the surface of the ultraviolet curable resin layer. There is a characteristic part to do.

  In the present invention, a molded body and a wire grid polarizer described below can be manufactured by a method for forming a fine pattern having the above-described characteristic portions. First, a molded body formed by the fine pattern forming method of the present invention and a structure of a wire grid polarizer using the molded body will be described.

  FIG. 1A is a schematic cross-sectional view of a molded body according to the present embodiment, and FIG. 1B is a schematic plan view of the molded body.

  The molded body 20 according to the present embodiment includes a base material 21 and an ultraviolet curable resin layer 22 provided on the surface 21 a of the base material 21.

  As shown in FIGS. 1A and 1B, a fine pattern 25 is formed on the surface 22 a of the ultraviolet curable resin layer 22 by providing a plurality of grid-like convex portions 23.

  The base material 21 is disposed on the back side of the ultraviolet curable resin layer 22 to improve the strength of the molded body 20 while maintaining the flexibility of the molded body 20.

  The pitch P of the grid-like convex portions 23 is about 80 to 140 nm, the height H1 is about 80 to 140 nm, and the grid width D is about 0.25 × pitch P to 0.4 × pitch Pnm. The film thickness H2 of the ultraviolet curable resin layer 22 is about 0.5 μm to 5 μm.

  Examples of the ultraviolet curable resin constituting the ultraviolet curable resin layer 22 include trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, propoxylated glyceryl triacrylate, and pentane. Erythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, trisacryloyloxyethyl phosphate, trifunctional The above polyester acrylate oligomer, trifunctional or higher Tan acrylate oligomer, tri- or higher functional epoxy acrylate oligomer, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane trimethacrylate, propoxylated trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, propoxylated glyceryl trimethacrylate, Pentaerythritol tetramethacrylate, ethoxylated pentaerythritol tetramethacrylate, ditrimethylolpropane tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, tris (2-hydroxyethyl) isocyanurate trimethacrylate, trismeta Acryloyloxyethyl phosphate 3 or more functional groups of the polyester methacrylate oligomer, trifunctional or higher urethane methacrylate oligomer and one or more of such tri- or higher-functional epoxy methacrylate oligomer.

  The ultraviolet curable resin layer 22 according to the present embodiment is obtained by curing an ultraviolet curable resin containing a photopolymerization initiator having a light absorption wavelength of 380 nm or more with ultraviolet rays having a wavelength of 380 nm or more.

  Although the upper limit of the light absorption wavelength of the photopolymerization initiator is not particularly limited, it is preferably about 430 nm in consideration of the absorption peak wavelength of the commercially available photopolymerization initiator.

  Examples of the photopolymerization initiator having a light absorption wavelength of 380 nm to 430 nm include diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis ( 2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium and the like. These photopolymerization initiators can be applied alone, but can also be used in combination of two or more. For example, Darocur (registered trademark) TPO (manufactured by BASF, absorption peak wavelength; 295 nm, 368 nm, 380 nm, 393 nm), Irgacure (registered trademark) 784 (manufactured by BASF, absorption peak wavelength: 398 nm, 470 nm), Darocur (registered trademark) ) 4265 (manufactured by BASF, absorption peak wavelength; 240 nm, 272 nm, 380 nm). The blending ratio of the photopolymerization initiator is about 0.5 to 5% by weight with respect to the ultraviolet curable resin.

  In addition, the ultraviolet curable resin layer 22 (ultraviolet curable resin) may have other conventional additives such as a flow regulator, a leveling agent, an extender, a plasticizer, as necessary, within a range that does not impair the original purpose. Agents, mold release agents, antioxidants, and the like.

  2A is a schematic cross-sectional view of the wire grid polarizer according to the present embodiment, and FIG. 2B is a schematic plan view of the wire grid polarizer. In FIG. 2, members denoted by the same reference numerals as those in FIG. 1 are the same as those in FIG.

  A wire grid polarizer (wire grid polarizing film) 30 can be obtained by depositing a metal layer (metal wire) 27 on the molded body 20 according to the present embodiment shown in FIG.

  As shown in FIG. 2A, a metal layer 27 is formed on one side surface of each grid-like convex portion 23 of the wire grid polarizer 30 via a dielectric layer 26. Therefore, as shown in FIG. 2B, a plurality of metal layers 27 extending in one direction are arranged at intervals. The dielectric layer 26 may not be formed. In such a case, the metal layer 27 is formed directly on the surface of the grid-like convex portion 23.

  The dielectric constituting the dielectric layer 26 may be substantially transparent in the visible region. A dielectric material having high adhesion between the material constituting the ultraviolet curable resin layer 22 and the metal constituting the metal layer 27 can be suitably used. For example, silicon (Si) oxides, nitrides, halides, carbides or their composites (dielectrics in which other elements, simple substances, or compounds are mixed in a dielectric), aluminum (Al), chromium ( Cr), yttrium (Y), zirconium (Zr), tantalum (Ta), titanium (Ti), barium (Ba), indium (In), tin (Sn), zinc (Zn), magnesium (Mg), calcium ( A simple substance of a metal oxide such as Ca), cerium (Ce), copper (Cu), nitride, halide, carbide or a composite thereof can be used.

  The metal constituting the metal layer 27 preferably has a high light reflectance in the visible light region and has high adhesion to the material constituting the dielectric layer 26. For example, it is preferably composed of aluminum (Al), silver (Ag), or an alloy thereof. From the viewpoint of cost, it is more preferable to be made of aluminum or an alloy thereof.

  A fine pattern 25 having an uneven cross-sectional shape provided on the surface of the ultraviolet curable resin layer 22 constituting the molded body 20 shown in FIG. 1 and the wire grid polarizer 30 shown in FIG. 2 is formed by a transfer device described below. It has been done.

  FIG. 3 is a schematic diagram of a roll-to-roll type transfer apparatus according to the present embodiment. In the transfer apparatus 100, first, the film-like base material 21 wound in a roll shape is continuously fed out from the feeding roll 31. The substrate 21 is conveyed to the application unit 40, and the ultraviolet curable resin 41 is applied by the application unit 40. The ultraviolet curable resin 41 contains the above-described photopolymerization initiator having a light absorption wavelength of 380 nm or more. That is, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, bis (η5-2,4-cyclopentadien-1-yl) -bis (photopolymerization initiator having a light absorption wavelength of 380 nm or more and 430 nm or less. 2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium and the like are included. Specifically, for example, Darocur (registered trademark) TPO (manufactured by BASF, absorption peak wavelength; 295 nm, 368 nm, 380 nm, 393 nm), Irgacure (registered trademark) 784 (manufactured by BASF, absorption peak wavelength: 398 nm, 470 nm) Darocur (registered trademark) 4265 (manufactured by BASF, absorption peak wavelength; 240 nm, 272 nm, 380 nm), and the like can be used. In this Embodiment, it is suitable to contain the compounding ratio of a photoinitiator about 0.5 to 5% by weight% with respect to ultraviolet curable resin.

  In addition, other conventional additives such as a flow regulator, a leveling agent, a bulking agent, a plasticizer, a mold release agent, an oxidation agent may be added to the ultraviolet curable resin 41 as long as the original purpose is not impaired. An inhibitor or the like can be included.

  In addition, the viscosity of the ultraviolet curable resin 41 is preferably several mPa · s to 100 mPa · s, for example, and several mPa · s to 50 mPa · s in view of high-speed productivity. The viscosity of the ultraviolet curable resin can be easily adjusted by adding an appropriate amount of a solvent such as a low-viscosity monofunctional monomer or ethanol.

  Then, the film-like sheet | seat in which the ultraviolet curable resin 41 was apply | coated to the surface of the base material 21 is conveyed to the transfer hardening part 60 which has the roll-shaped stamper (transfer roll) 50. FIG. As shown in FIG. 3, the sheet is sandwiched between the roll stamper 50 and the nip roll 56 and tension is applied to press the sheet against the outer peripheral surface of the roll stamper 50.

  As shown in FIG. 3, the transfer curing unit 60 is provided with a light source 51 facing the roll stamper 50 at a predetermined interval.

  FIG. 4 is a partially enlarged schematic view of a transfer curing portion of the transfer device. As shown in FIG. 4, an uneven fine pattern 52 is formed on the surface of the roll-shaped stamper 50. The grid-like convex portions 54 constituting the fine pattern 52 extend in a direction perpendicular to the conveyance direction A of the sheet 53 in which the ultraviolet curable resin 41 is applied to the surface of the base material 21. Therefore, the fine pattern 52 has a structure in which convex portions and concave portions are continuous in the transport direction A. In FIG. 4, the ratio of the height to the width of the fine pattern 52 is changed from that in FIGS. 1 and 2 for easy illustration.

  As shown in FIG. 4, a release layer 55 is formed on the surface of the fine pattern 52. The release layer 55 is formed of a release agent such as fluorine or silicon. Examples of commercially available release agents include Daikin Industries, Ltd. OPTOOL (registered trademark) HD2100, Harves Durasurf (registered trademark), Sumitomo 3M Novec (registered trademark), and the like.

  As shown in FIG. 4, the ultraviolet curable resin 41 in the sheet 53 is in pressure contact with the fine pattern 52 of the roll stamper 50 through the release layer 55. Accordingly, the sheet 53 is conveyed by the roll stamper 50 while a fine pattern (which is a reverse pattern to the fine pattern 52 of the roll stamper 50) is transferred onto the surface of the ultraviolet curable resin 41, and at a position facing the light source 51. The ultraviolet curable resin 41 is cured by the ultraviolet light emitted from the light source 51. As described above, the ultraviolet curable resin layer 22 is obtained by curing the ultraviolet curable resin 41 containing a photopolymerization initiator having a light absorption wavelength of 380 nm or more with ultraviolet rays having a wavelength of 380 nm or more.

  Then, the protective film F1 is supplied from the supply roll 70 shown in FIG. 3, and the protective film F1 is overlaid on the surface of the sheet 53 on which the fine pattern is formed. And the sheet | seat 53 with the protective film F1 is wound up by the winding roll 80. FIG.

  In order to manufacture a wire grid polarizer (wire grid polarizing film), a metal is formed by sputtering or vacuum deposition on the fine pattern 25 side formed on the surface of the film-like sheet 53 obtained by the transfer device 100 of FIG. To do. Preferably, the metal layer 27 is formed on one side surface of the fine pattern 25. At this time, the metal layer 27 can be appropriately formed on one side surface of the grid-like convex portion 23 by depositing metal toward one side surface of the grid-like convex portion 23 shown in FIG. 2A.

  In the present embodiment, in the fine pattern forming method, wavelength limiting means for limiting the wavelength of ultraviolet light emitted from the light source 51 shown in FIG. 4 is provided to improve transferability. Specifically, ultraviolet light having a short wavelength of less than 380 nm is cut so that strong energy having a short wavelength does not act on the release layer 55.

  Hereinafter, the wavelength limiting means will be described in detail. FIG. 5 is a partial schematic view showing a transfer curing portion of the transfer device, and is a view for explaining the first wavelength limiting means. In FIG. 5, members denoted by the same reference numerals as those in FIGS. 3 and 4 indicate the same parts as those in FIGS. 3 and 4. In FIG. 5, as in FIG. 4, the surface of the roll-shaped stamper 50 is provided with a fine pattern 52 and a release layer 55 having a concavo-convex shape, which are omitted in the drawing.

  In FIG. 5, a light source 63 limited to an irradiation wavelength of 380 nm or more is used as the first wavelength limiting means. That is, the first wavelength limiting unit has a configuration in which the wavelength of the ultraviolet light UV1 irradiated from the light source 63 is limited to 380 nm or more. The light source 63 is preferably a single wavelength LED in which the irradiated ultraviolet light UV1 is limited to a wavelength of 380 nm or more. For example, LEDZero series from Fine Sensing can be used. The emission wavelength of the single wavelength LED is, for example, 400 nm (380 nm to 410 nm) or 395 ± 5 nm.

  In the present embodiment, the ultraviolet curable resin 41 contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more. Therefore, the ultraviolet curable resin 41 can be appropriately cured by the ultraviolet light UV1 having a wavelength of 380 nm or more emitted from the light source 63.

  In the configuration shown in FIG. 5, ultraviolet light having a short wavelength of less than 380 nm is not irradiated from the light source 63, so that the release layer 55 is not decomposed by strong energy having a short wavelength as in the prior art. A fine pattern formed on the surface can be formed without defects and the number of transfers can be increased.

  Conventionally, the durability of the release layer coated on the stamper surface made of Ni or the like is about 200 times transfer (1 m / min, roll shape) in a roll-to-roll type fine pattern transfer device. The circumferential length of the stamper 50 was 82 mm, about 1 hour). That is, when the transfer exceeds 200 times, the release layer is separated by the strong energy of short wavelength in the ultraviolet light, and the ultraviolet curable resin cannot be easily released from the stamper. At this time, the ultraviolet curable resin remained on the stamper surface, and a transfer shape defect was formed on the molded body. As shown in the experiment described later, when the transfer defect is a wire grid polarizer, several hundreds of large black spot defects in mm units appeared.

  On the other hand, in the present embodiment, the roll-to-roll type fine pattern transfer device can perform transfer of several thousand times or more, and the optical performance of the wire grid polarizer can be achieved even if transfer is performed several thousand times or more. There were only a few fine black spots (size on the μm level) that had no effect.

  FIG. 6 is a partial schematic view showing a transfer curing portion of the transfer apparatus, and is a view for explaining the second wavelength limiting means. In FIG. 6, members denoted by the same reference numerals as those in FIGS. 3 and 4 indicate the same parts as those in FIGS. 3 and 4. In FIG. 6, as in FIG. 4, the surface of the roll stamper 50 is provided with a fine pattern 52 and a release layer 55 having a concavo-convex shape, which are omitted in the drawing.

  In FIG. 6, a band pass filter 65 serving as a second wavelength limiting unit is provided between the light source 64 and the roll stamper 50. That is, the band pass filter 65 is located in the middle of the light irradiation path from the light source 64 to the ultraviolet curable resin 41. The “intermediate” may be anywhere in the light irradiation path, and is preferably directly above the roll stamper 50.

  The band-pass filter 65 shown in FIG. 6 is configured to limit the irradiation wavelength to the ultraviolet curable resin 41 to 380 nm or more, that is, to cut a short wavelength of less than 380 nm. As the bandpass filter 65, for example, a dielectric multilayer film having a structure in which a dielectric thin film having a high refractive index and a dielectric thin film having a low refractive index are alternately laminated on a base material such as glass is used. It is done.

  As the light source 64 shown in FIG. 6, for example, a high-pressure UV lamp, a metal halide lamp, or the like can be used.

  FIG. 8A is a diagram showing a spectral distribution when a high-pressure UV lamp is used as the light source according to the present embodiment, and FIG. 8B shows a spectral distribution when a metal halide lamp is used as the light source according to the present embodiment. FIG.

  As shown in FIG. 8A, the spectral distribution of the high-pressure UV lamp is about 250 nm to about 570 nm, and the high-pressure UV lamp emits a broadband wavelength. Similarly, in the metal halide lamp shown in FIG. 8B, the spectral distribution is about 250 nm to about 570 nm.

  When the ultraviolet light UV2 including a short wavelength of less than 380 nm is irradiated from the light source 64 in this way, the wavelength of less than 380 nm is cut by the bandpass filter 65 as the wavelength limiting means, and the ultraviolet light UV3 passing through the bandpass filter 65 is obtained. Is limited to those having a wavelength of 380 nm or more.

  As a result, the sheet 53 that is in close contact with the surface of the roll stamper 50 via the release layer 55 is irradiated with ultraviolet light UV3 limited to a wavelength of 380 nm or more.

  In the present embodiment, the ultraviolet curable resin 41 contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more. Therefore, the ultraviolet curable resin 41 can be appropriately cured by the ultraviolet light UV3 limited to an irradiation wavelength of 380 nm or more by the bandpass filter 65.

  In this way, in the configuration of FIG. 6, since the ultraviolet light having a short wavelength is cut by the bandpass filter 65, the release layer 55 is not decomposed by the strong energy of the short wavelength unlike the conventional case, and compared with the conventional case. Even if the number of times of transfer is increased, the occurrence of transfer defects can be suppressed.

  According to the configuration of FIG. 6, it is not necessary to limit the light source 64 in particular, and the conventionally used light source 64 or the like can be used.

  FIG. 7 is a partial schematic diagram illustrating a transfer curing unit of the transfer apparatus, and is a diagram for explaining a third wavelength limiting unit. In FIG. 7, members denoted by the same reference numerals as those in FIGS. 3 and 4 indicate the same parts as those in FIGS. 3 and 4. In FIG. 7, as in FIG. 4, the surface of the roll stamper 50 is provided with a fine pattern 52 and a release layer 55 having a concavo-convex shape, which are omitted in the drawing.

  FIG. 7 is a partially enlarged schematic view showing a part thereof in an enlarged manner. A transparent base material is used as the third wavelength limiting means for absorbing the irradiation wavelength of less than 380 nm on the base material 21 shown in the partially enlarged schematic view of FIG.

  As shown in FIG. 7, the ultraviolet light UV <b> 4 irradiated from the light source 66 first enters the substrate 21. Therefore, the ultraviolet light UV5 entering the ultraviolet curable resin 41 from the base material 21 by cutting (light absorption) the irradiation wavelength of less than 380 nm at the base material 21 is an ultraviolet light with the irradiation wavelength of less than 380 nm cut. Thus, the ultraviolet light having a wavelength of less than 380 nm is controlled not to enter the ultraviolet curable resin 41.

  Although the base material 21 which absorbs an irradiation wavelength of less than 380 nm is not particularly limited, it is preferable to use, for example, a film made of triacetyl cellulose (TAC). By using the TAC film, the substrate 21 can appropriately absorb the irradiation wavelength of less than 380 nm.

  FIG. 9 is a graph showing the relationship between the wavelength and the light transmittance in base materials made of different materials. The horizontal axis in FIG. 9 indicates the wavelength, and the vertical axis indicates the light transmittance.

  As shown in FIG. 9, in the TAC film, the light transmittance for ultraviolet light having a wavelength of less than 380 nm can be suppressed to about 3% or less. In other words, the TAC film can absorb 97% or more of ultraviolet light having a wavelength of less than 380 nm.

  On the other hand, polycarbonate (PC), cycloolefin polymer (COP), and polyethylene terephthalate (PET) all have extremely high light transmittance of about 85% to 90% with respect to ultraviolet rays having a wavelength of less than 380 nm.

  In the present embodiment, the ultraviolet curable resin 41 contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more. Therefore, the ultraviolet curable resin 41 can be appropriately cured by the ultraviolet rays limited to the wavelength of 380 nm or more by the base material 21.

  In this way, in the configuration of FIG. 7, the ultraviolet light having a short wavelength is cut by the base material 21, so that the release layer 55 is not decomposed by the strong energy of the short wavelength as in the conventional case, and compared with the conventional case. Even if the number of times of transfer is increased, the occurrence of transfer defects can be suppressed.

  In the embodiment shown in FIG. 7, a high-pressure UV lamp, a metal halide lamp, or the like can be used as the light source 66 in the same manner as in FIG. 6, and is not particularly limited.

  In FIG. 7, unlike FIG. 6, the band-pass filter 65 that cuts ultraviolet light having a wavelength of less than 380 nm may not be provided, but may be provided.

  Further, as shown in FIG. 5, the first wavelength limiting means using the light source 63 in which the irradiation wavelength is limited to 380 nm or more, and the wavelength of less than 380 nm between the light source 64 and the roll stamper 50 as shown in FIG. When the second wavelength limiting means provided with the bandpass filter 65 to be cut is used, the material of the base material 21 used for the sheet 53 is not limited. Therefore, polycarbonate (PC), cycloolefin polymer (COP), polyethylene terephthalate (PET), polyethylene naphthalate, polystyrene, polyethylene, acrylic, polyimide-based highly permeable film, or the like can be used for the substrate 21. 5 and 6, it is possible to use a TAC film for the base material 21.

  5 and 6 may be configured to cure the ultraviolet curable resin by irradiating ultraviolet light from the roll stamper 50 side. In such a case, the roll stamper 50 needs to be formed of a transparent material instead of Ni or the like.

  As shown in FIG. 5, the transfer device 100 shown in FIG. 3 uses a light source 63 such as a single wavelength LED restricted to an irradiation wavelength of 380 nm or more, as shown in FIG. 5, or as shown in FIG. A band pass filter 65 that cuts a wavelength of less than 380 nm is provided between the light source 64 and the roll stamper 50.

  In the present embodiment, the thickness of the ultraviolet curable resin 41 is preferably in the range of 0.5 μm or more and 5 μm or less. The thickness of the ultraviolet curable resin 41 here is a thickness when the ultraviolet curable resin 41 is applied on the base material 21 and before the fine pattern 25 is formed on the surface by pressing the roll-shaped stamper 50. It is thickness. Therefore, as shown in FIG. 1, the thickness of the ultraviolet curable resin layer 22 in a state where the fine pattern 52 of the roll stamper 50 is pressed and cured and contracted on the surface is about 0.4 μm to 4.5 μm.

  If the thickness of the ultraviolet curable resin 41 becomes too thick, uniform photocuring cannot be performed in the film thickness direction, and the curing shrinkage increases, causing a problem that the sheet 53 is warped, and the thickness of the ultraviolet curable resin 41 is increased. If the thickness is too thin, when foreign matter such as dust adheres to the base material 21, the foreign matter cannot be properly embedded in the ultraviolet curable resin 41 and a fine pattern cannot be appropriately formed on the surface. Arise.

  In order to solve the above problem, the thickness of the ultraviolet curable resin 41 was set in the range of 0.5 μm to 5 μm. The thickness of the ultraviolet curable resin 41 is preferably 1 μm or more, and more preferably 2 μm or more. Thereby, the influence of the above-described foreign matter can be suppressed.

  As described above, the inventors press the roll-shaped stamper 50 having the fine pattern 52 provided with the release layer 55 on the surface of the ultraviolet curable resin 41 laminated on the base material 21. In the method for forming the fine pattern 25 in which the ultraviolet curable resin 41 is irradiated with ultraviolet rays to cure the ultraviolet curable resin 41, the ultraviolet curable resin 41 contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more, By providing a wavelength limiting means for limiting the irradiation wavelength to 380 nm or more, the durability of the release layer 55 provided on the surface of the roll stamper 50 is improved because the roll stamper 50 is not exposed to short wavelength light. The present inventors have found that transferability can be improved.

  In other words, the durability of the release layer 55 provided on the surface of the roll-shaped stamper 50 is improved by the above configuration. Therefore, even if the UV curable resin layer 22 is peeled off from the roll-shaped stamper 50 by repeatedly transferring, the roll It is difficult for the ultraviolet curable resin to remain on the surface of the stamper 50, and it is possible to suppress the occurrence of a transfer shape defect in the fine pattern 25 transferred to the molded body 20 as the number of transfers increases.

  In the present embodiment, as the wavelength limiting unit, the first wavelength limiting unit using the light source 63 whose irradiation wavelength is limited to 380 nm or more, and the second band-pass filter 65 that cuts a wavelength of less than 380 nm are used. A wavelength limiting means and a third wavelength limiting means using a substrate that absorbs wavelengths less than 380 nm were presented. These wavelength limiting means may be used alone, or a plurality of wavelength limiting means may be combined. In addition, the wavelength limiting means that can limit the irradiation wavelength to 380 nm or more is not limited to the above three types, and other wavelength limiting means may be used.

  As described above, in the present embodiment, the case where the fine pattern is continuously formed by the roll-to-roll type transfer device has been described. However, the present invention is not limited to this, and the same effect can be obtained in the batch-type transfer device shown in FIG. Play.

  FIG. 10 is a schematic cross-sectional view for explaining the batch transfer method. As shown in FIG. 10A, a fine pattern having a concavo-convex cross section is formed on the surface of the stamper 90 (on the lower surface side in FIG. 10A), and a release layer 91 is provided along the surface of the fine pattern. As shown in FIG. 10A, an ultraviolet curable resin 41 is applied to the surface of the base material 21, and the surface of the stamper 90 on which a fine pattern is formed is pressed against the surface of the ultraviolet curable resin 41.

  In the state of FIG. 10A, ultraviolet light is irradiated by the light source 92 disposed on the base 21 side, and the ultraviolet curable resin 41 is cured.

  The ultraviolet curable resin 41 contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more. Therefore, the ultraviolet curable resin 41 can be cured by ultraviolet light having a wavelength of 380 nm or more.

  In FIG. 10B, the stamper 90 is separated from the ultraviolet curable resin layer 22. As shown in FIG. 10B, the fine pattern 25 is transferred to the surface of the ultraviolet curable resin layer 22.

  In a batch type transfer apparatus, the light source 92 in FIG. 10A is a light source such as a single wavelength LED limited to a wavelength of 380 nm or more, or a band pass filter that cuts a wavelength less than 380 nm between the light source 92 and the stamper 90. Is provided. Or the transparent base material which absorbs the irradiation wavelength of less than 380 nm like the TAC film for the base material 21 is used.

  As described above, it is possible to prevent the release layer 91 from being decomposed or the like without being exposed to ultraviolet rays having a short wavelength of less than 380 nm. Therefore, the number of times of transfer can be increased as compared with the conventional case, and the occurrence of transfer defects can be suppressed, and transferability can be effectively improved.

  Hereinafter, although the formation method of the fine pattern in this invention is demonstrated using a comparative example and an Example, these are described for description, Comprising: The range of this invention is limited to the following Example is not.

(Comparative Example 1)
An MLR3000B-27 metal halide (manufactured by Sen Special Light Source) is used as an ultraviolet light source, and a roll stamper having a fine pattern with a pitch (P) of 100 nm, a grid width (D) of 30 nm, and a height (H1) of 100 nm by Ni electroforming. used. The circumferential length of the roll stamper is 260 mm. Optool (registered trademark) HD2100 (manufactured by Daikin Industries) was previously coated on the surface on which the fine pattern of the roll stamper was formed by a processing method designated by the manufacturer. It was immersed in Optool (registered trademark) HD2100Z, pulled up, left to stand at 24 ° C. and 50% RH for 2 hours, and dried. Next, after immersing and rinsing in a rinse liquid Durasurf (registered trademark) HD-ZV (manufactured by Harves Co., Ltd.), it was dried at 24 ° C. and 50% RH for 2 hours to form a release layer. A PET film (manufactured by Toyobo) was used as the transparent substrate.

  In addition, 32% by weight of trimethylolpropane triacrylate (TMPTA), 32.5% by weight of 1,9 nonanediol diacrylate, 33% by weight of N-vinyl-2-pyrrolidone (NVP), and 0.1% of silicon diacrylate. 5% by weight and 2% by weight of Irgacure (registered trademark) 184 (manufactured by BASF, absorption peak wavelength; 246 nm, 280 nm, 333 nm) as a photopolymerization initiator were blended to prepare an ultraviolet curable resin.

  And said ultraviolet curable resin was apply | coated on PET film, and transfer hardening was implemented continuously.

  When the stamper was visually observed and the molded body after transfer curing was observed, the resin adhered to the stamper surface and the transfer shape defect of the molded body appeared after about 200 rotations (about 1 hour) of transfer curing.

  Subsequently, aluminum was obliquely deposited on the molded body to form a wire grid polarizing film.

  FIG. 11A is a schematic plan view of a transfer defect observed in a wire grid polarizer in a comparative example.

  As shown in FIG. 11A, a black spot defect 95 having a diameter of 100 μm or more (some of which is several mm) was visually observed. This black spot defect 95 is a spot where aluminum, which is a metal, is deposited at a place where the grid-like convex portion has been removed from the molded body 20 and appears as a black spot. In Comparative Example 1, it was found that 100 or more black spot defects 95 shown in FIG. 11A exist.

(Comparative Example 2)
The base film was TAC (Fuji Film Co., Ltd.), and a molded body was obtained in the same manner as in Comparative Example 1. The transmittance of the TAC film at a wavelength of 380 nm is about 3% (see FIG. 9). As described above, since the TAC film does not transmit light having a wavelength of less than 380 nm, an ultraviolet curable resin containing Irgacure (registered trademark) 184 as a photopolymerization initiator having absorption peak wavelengths of 246 nm, 280 nm, and 333 nm is cured. Thus, it was impossible to obtain a molded body having a fine pattern on the surface.

Example 1
Photopolymerization of Darocur (registered trademark) TPO (manufactured by BASF, absorption peak wavelengths; 295 nm, 368 nm, 380 nm, 393 nm) starting with photopolymerization at 380 nm or longer, which is longer than the optical absorption wavelength of the TAC film, is used as the base film. A molded product was obtained in the same manner as in Comparative Example 1 using the agent.

  In Example 1, the adhesion of the resin to the stamper surface on which the fine pattern was formed and the transfer shape defect of the molded body were not observed in the transfer curing of about 4500 times (about 20 hours).

  In the same manner as in Comparative Example 1, aluminum was obliquely deposited on the molded body to form a wire grid polarizing film. FIG. 11B is a schematic plan view of a transfer defect observed in the wire grid polarizer in this example. In Example 1, the minute black spots 96 having a diameter of about several tens of μm shown in FIG. 11B were observed. However, the number of the black spots 96 is 5 or less, and both the size and the number do not cause a problem with respect to the optical performance. Met.

(Comparative Example 3)
The base film was a PET film, and a molded body was obtained in the same manner as in Example 1. As shown in FIG. 9, the transmittance of the PET film at a wavelength of 380 nm is about 87%.

  In the same manner as in Example 1, aluminum was obliquely deposited on the molded body to form a wire grid polarizing film.

  In Comparative Example 3, resin adhesion to the stamper surface on which the fine pattern was formed and transfer shape defects of the molded body were observed in the transfer curing of about 200 times (about 1 hour). When the transfer shape defect (black spot defect) was evaluated in the same manner as in Comparative Example 1, it was found that there were 100 or more black spot defects 95 (having a diameter of 100 μm or more (some of which were several mm) visually) shown in FIG. 11A. It was.

  In Comparative Example 3, as in Example 1, the ultraviolet curable resin contains Darocur (registered trademark) TPO that starts photopolymerization at 380 nm or more, and therefore it is possible to cure the ultraviolet curable resin. However, since the base film was made of PET, it was found that the release property was affected by the short wavelength of less than 380 nm and the transferability was lowered.

(Comparative Example 4)
The base film was changed to COP (Arton (registered trademark), manufactured by JSR), and a molded body was obtained in the same manner as in Example 1. As shown in FIG. 9, the transmittance of the COP film at a wavelength of 380 nm is about 90%. And aluminum was diagonally vapor-deposited on the molding, and the wire grid polarizing film was formed.

  In Comparative Example 4, resin adhesion to the stamper surface and transfer shape defects of the molded product were observed in the transfer curing of about 200 times (about 1 hour). When the transfer shape defect (black spot defect) was evaluated in the same manner as in Comparative Example 1, it was found that there were 100 or more black spot defects 95 (having a diameter of 100 μm or more (some of which were several mm) visually) shown in FIG. 11A. It was.

  In Comparative Example 4, as in Example 1, the ultraviolet curable resin contains Darocur (registered trademark) TPO that starts photopolymerization at 380 nm or more, and thus it is possible to cure the ultraviolet curable resin. However, since the base film was made of COP, it was found that the release property was affected by a short wavelength of less than 380 nm and the transferability was lowered.

(Example 2)
A band-pass filter that transmits light with a wavelength of 380 nm to 430 nm and blocks light with other wavelengths is provided between the metal halide lamp light source and the roll stamper. A molded body was obtained in the same manner as in Comparative Example 3. Further, aluminum was obliquely deposited on the molded body to form a wire grid polarizing film.

  In Example 2, the resin adhesion to the stamper surface and the transfer shape defect of the molded body were not observed in the transfer curing of about 4600 times (about 20 hours). In Example 2, fine black spots 96 having a diameter of about several tens of μm shown in FIG. 11B were observed in the wire grid polarizing film. However, the number of black spots 96 is 5 or less, and both the size and the number are related to optical performance. On the other hand, the level was not problematic.

(Example 3)
A band-pass filter that transmits light with a wavelength of 380 nm to 430 nm and blocks light with other wavelengths is provided between the metal halide lamp light source and the roll stamper. A molded body was obtained in the same manner as in Comparative Example 4. Further, aluminum was obliquely deposited on the molded body to form a wire grid polarizing film.

  In Example 3, the resin adhesion to the stamper surface and the transfer shape defect of the molded body were not observed in the transfer curing of about 4600 times (about 20 hours). In Example 3, fine black spots 96 having a diameter of about several tens of μm shown in FIG. 11B were observed in the wire grid polarizing film. However, the number of black spots 96 is 5 or less, and both the size and the number are related to optical performance. On the other hand, the level was not problematic.

Example 4
An LED light source (LEDZero PinCure (registered trademark), manufactured by Fine Sensing Co., Ltd.) having a peak wavelength at a wavelength of 390 nm was used. The illuminance was 0.35 W / cm ² . A molded body was obtained in the same manner as in Comparative Example 4. Further, aluminum was obliquely deposited on the molded body to form a wire grid polarizing film.

  In Example 4, the resin adhesion to the stamper surface and the transfer shape defect of the molded body were not observed in the transfer curing of about 4600 times (about 20 hours). In Example 4, fine black spots 96 having a diameter of about several tens of μm as shown in FIG. 11B were observed in the wire grid polarizing film. However, the number of black spots 96 is 5 or less, and both the size and the number are related to optical performance. On the other hand, the level was not problematic.

  According to the method for forming a fine pattern of the present invention, it is possible to provide a molded body having no defects continuously. And a molding can be applied to manufacture of a wire grid polarizer, the antireflection film by a fine pattern, etc. Each of these optical elements has a fine pattern formed on the surface with high accuracy and has no transfer shape defect (or very few defects), so that it can exhibit excellent optical performance.

DESCRIPTION OF SYMBOLS 20 Molded body 21 Base material 21a Base material surface 22 UV curable resin layer 22a UV curable resin layer surface 23, 54 Lattice-shaped convex portions 25, 52 Fine pattern 26 Dielectric layer 27 Metal layer 30 Wire grid polarizer 40 Application 41 UV curable resin 50 Roll-type stamper 51, 63, 64, 66, 92 Light source 53 Sheet 55, 91 Release layer 60 Transfer curing part 65 Band pass filter 90 Stamper 95 Black spot defect 96 Black spot 100 Transfer device F1 Protective film

Claims (10)

The ultraviolet curable resin is cured by irradiating ultraviolet rays in a state where the surface of the ultraviolet curable resin provided on the substrate is pressed against the surface of the stamper having the fine pattern provided with the release layer. A fine pattern forming method for transferring the fine pattern,
The ultraviolet curable resin contains a photopolymerization initiator having a light absorption wavelength of 380 nm or more, and has wavelength limiting means for limiting the irradiation wavelength of ultraviolet rays to the ultraviolet curable resin to 380 nm or more. A method for forming a fine pattern.   2. The fine pattern forming method according to claim 1, wherein a light source limited to an irradiation wavelength of 380 nm or more is used as the wavelength limiting means.   The method for forming a fine pattern according to claim 2, wherein the light source is a single wavelength LED light source.   The bandpass filter which restrict | limits an irradiation wavelength to 380 nm or more is used in the middle of the light irradiation path | route from a light source to the said ultraviolet curable resin as said wavelength limitation means. Method for forming a fine pattern.   The fine pattern according to any one of claims 1 to 4, wherein a transparent base material that absorbs an irradiation wavelength of less than 380 nm is used as the wavelength limiting means, and the ultraviolet rays are irradiated from the transparent base material side. Forming method.   6. The method for forming a fine pattern according to claim 1, wherein the ultraviolet curable resin has a thickness in a range of 0.5 to 5 [mu] m.   A substrate and an ultraviolet curable resin layer formed on the surface of the substrate, and the fine pattern is formed on the surface of the ultraviolet curable resin layer by the method according to claim 1. Molded product characterized by being made.   A wire grid polarizer, wherein a metal layer is formed on at least a part of the surface of the fine pattern of the molded body according to claim 7. The ultraviolet curable resin is cured by irradiating ultraviolet rays in a state where the surface of the ultraviolet curable resin provided on the substrate is pressed against the surface of the stamper having the fine pattern provided with the release layer. A transfer device for transferring the fine pattern,
2. A transfer apparatus comprising wavelength limiting means for limiting an irradiation wavelength of ultraviolet rays to the ultraviolet curable resin to 380 nm or more.   As the wavelength limiting means, at least one of a light source limited to an irradiation wavelength of 380 nm or more, or a bandpass filter that limits the irradiation wavelength to 380 nm or more in the middle of a light irradiation path from the light source to the ultraviolet curable resin. The transfer device according to claim 9, wherein the transfer device is used.

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