JP6252769B2 - Imprint transfer product, imprint transfer mold, and imprint transfer method - Google Patents

Description

  The present disclosure relates to a technical field to which nanoimprint lithography is applied, and more particularly, to an imprint transfer product, an imprint transfer mold for forming the transfer product, and an imprint transfer method.

  In recent years, attention has been focused on nanoimprint lithography that transfers a concavo-convex structure to a molding material by pressing fine irregularities formed on a transfer mold (mold) against the molding material (transfer material). According to this imprint technique, a fine structure from nm scale to μm scale can be formed. For this reason, development aimed at application to various fields such as displays, optical devices, and semiconductor devices is underway.

  Typical imprint methods include a thermal method using a thermoplastic material and an optical method using an ultraviolet (UV) curable material. Typical imprint transfer methods include a flat plate method and a roll method. The flat plate method is often used when transfer accuracy is good and a high aspect ratio is required or when more precise molding is required. On the other hand, the roll method is excellent in productivity and has an uneven structure on a long object. Can be formed efficiently. In any method, improvement in productivity is required in order to manufacture a device having a fine structure in a large amount at a low cost. In particular, in recent years, in order to manufacture a device with a large area, there has been a demand for a large imprint area.

  Patent Document 1 discloses an example of such an imprint technique. Patent Document 1 discloses that a nano-imprint roll having a large area can be produced at low cost by repeating an operation of transferring a concavo-convex shape using a small-area original plate on a large-area roll surface.

JP 2007-203576 A

  According to the prior art, when a large-area imprint transfer mold is manufactured, a transfer using a small-area mold is repeated, so that a step can be formed in the uneven shape at the joint. When a transfer mold having such a step is pressed against the transfer material, air is trapped between the transfer mold and the transfer material, and a transfer defect may occur.

  In order to solve the above problem, an imprint transfer mold according to an aspect of the present disclosure includes a first region, a second region adjacent to the first region, and having an average thickness larger than that of the first region. A concavo-convex structure having In the first region, the height of the plurality of irregularities in the portion adjacent to the second region is monotonously decreased in the direction from the first region toward the second region, or in the second region, the height The heights of the plurality of irregularities in the portion adjacent to the first region are monotonously decreasing in the direction from the second region toward the first region.

  An imprint transfer product according to another aspect of the present disclosure includes a base material and a concavo-convex structure formed on the base material. The concavo-convex structure has a first region and a second region adjacent to the first region and having an average remaining film thickness smaller than that of the first region. In the first region, the height of the plurality of irregularities in the portion adjacent to the second region is monotonously decreased in the direction from the first region toward the second region, or in the second region, the height The heights of the plurality of irregularities in the portion adjacent to the first region are monotonously decreasing in the direction from the second region toward the first region.

  An imprint transfer method according to still another aspect of the present disclosure is a method for producing an imprint transfer product using the above-described imprint transfer mold. The method includes pressing the imprint transfer mold against a transfer material on a substrate, curing the transfer material, and peeling the imprint transfer mold from the transfer material.

  According to the above aspect, air confinement between the transfer mold and the transfer material can be relaxed and the occurrence of defective transfer defects can be suppressed.

It is a figure which shows an example of the method of producing a transfer mold of a large area, (a) is an original plate, (b) is a plurality of film molds, (c) is an assembly of a plurality of film molds, (d) Indicates a transcription type. It is sectional drawing which shows the example of the junction part of two adjacent film type | molds. It is sectional drawing which expands and shows the junction part of two adjacent film type | molds. It is sectional drawing which shows a mode that the transfer type | mold is produced from the film type | mold. It is sectional drawing which shows an example of a transfer type | mold. It is sectional drawing which shows the condition which forms the transcription | transfer material from a transfer type | mold using a roller. It is sectional drawing which shows the transcription | transfer material which has a transfer defect defect. It is a figure which shows the method of producing the transfer type | mold in Embodiment 1 of this indication, (a) is an original plate, (b) is a several film type, (c) is an aggregate | assembly of a plurality of film types, ( d) shows a transfer mold. 3 is a diagram illustrating an example of an original plate in Embodiment 1. FIG. 3 is a cross-sectional view showing an example of two adjacent film-type joints in Embodiment 1. FIG. FIG. 3 is an enlarged cross-sectional view of two adjacent film-type joints in the first embodiment. FIG. 3 is a cross-sectional view illustrating a state where a transfer mold is manufactured from the film mold in the first embodiment. 3 is a cross-sectional view showing a transfer mold in Embodiment 1. FIG. It is sectional drawing which shows the condition which forms the transfer material from the transfer type | mold using the roller in Embodiment 1. FIG. FIG. 3 is a cross-sectional view showing a transferred product in Embodiment 1. It is sectional drawing which shows the example of the junction part of the two adjacent film type | molds in the modification of Embodiment 1. It is sectional drawing which expands and shows the junction part of the two adjacent film type | molds in the modification of Embodiment 1. FIG. It is sectional drawing which shows a mode that the transfer type | mold is produced from the film type | mold in the modification of Embodiment 1. FIG. 6 is a cross-sectional view showing a transfer mold in a modified example of Embodiment 1. It is sectional drawing which shows the condition which forms the transfer material from the transfer type | mold using the roller in the modification of Embodiment 1. FIG. 6 is a cross-sectional view showing a transfer product in a modified example of Embodiment 1. It is a figure which shows the method of producing the transfer type | mold in Embodiment 2 of this indication, (a) is an original plate, (b) is a film type, (c) is a plurality of film types, (d) is a plurality of types. The film type assembly is shown in FIG. FIG. 6 is a cross-sectional view showing a transfer mold and a transfer product in Embodiment 2. FIG. 6 is a cross-sectional view showing a transferred product in Embodiment 2. It is sectional drawing which shows an example of the light emitting element in Embodiment 3 of this indication. It is a figure which shows a diffraction grating pattern. It is a graph which shows the dependence of the light extraction efficiency with respect to the height of an uneven structure. It is a graph which shows the dependence of the light extraction efficiency with respect to the pitch of an uneven structure. It is a figure for demonstrating the size in a transfer type | mold. It is a figure which shows the relationship between the level | step difference of a transfer type | mold, and uneven | corrugated height. It is sectional drawing which shows the transcription | transfer type | mold and transcription | transfer material in embodiment in which the inclined surface was formed between the 1st area | region and the 2nd area | region. It is sectional drawing of the transcription | transfer material in embodiment in which the slope was formed between the 1st area | region and the 2nd area | region. It is sectional drawing which shows the transcription | transfer material whose unevenness height of a 2nd area | region is the fixed value (alpha). It is sectional drawing which shows the transcription | transfer material whose unevenness | corrugation height of the part away from the 1st area | region in the 2nd area | region is the fixed value (beta). It is a figure which shows a several triangular film type. It is a figure which shows the aggregate | assembly which connected the several triangular film type. It is a figure which shows several hexagonal film type | molds. It is a figure which shows the aggregate | assembly which connected the some hexagonal film type | mold. It is a figure which shows an example of the uneven structure which has a line and space pattern. It is a figure which shows an example of the uneven structure in which randomness was suppressed. It is a figure which shows the other example of the uneven structure in which randomness was suppressed. It is a figure for demonstrating the Fourier component of a random pattern. It is a figure for demonstrating the average period of an uneven structure. It is another figure for demonstrating the average period of an uneven structure.

  Prior to describing the embodiments of the present disclosure, the knowledge underlying the present disclosure will be described.

  As a method for producing an imprint transfer mold having a large area, there is a method of performing electroforming using a mold obtained by connecting a plurality of relatively small molds, in addition to the conventional method described above. FIG. 1 shows an example of such a method. First, as shown in FIG. 1A, an original plate (master mold) 101 having a desired uneven shape formed on the surface is prepared. A plurality of film molds (replica molds) 102 shown in FIG. 1B are produced by transferring the concavo-convex shape onto the film using the original plate 101. Next, as shown in FIG. 1 (c), the plurality of film molds 102 are connected to produce a large-area film mold assembly. A large-area imprint transfer mold 103 as shown in FIG. 1 (d) can be produced by performing electroforming using this film mold assembly as a mold and a metal such as Ni.

  Here, the “original plate” (master mold) refers to a mold from which a transfer mold is produced. “Film mold” (replica mold) refers to a mold for producing a transfer mold from an original plate. The film mold can be formed from a sheet-like material that can be easily joined to form a large area. The “transfer mold” refers to a mold used for producing a transfer product by nanoimprint lithography. “Transfer” refers to a product obtained by pressing a transfer mold against a transfer material, curing the transfer material, and peeling the transfer mold. The transferred material can be used, for example, as an optical sheet having a concavo-convex structure provided on an optical element such as an organic EL element or a light extraction structure.

  The transfer mold 103 has a transfer mold step 103A at a portion corresponding to a place where the film molds 102 are joined together. 2A to 2D are diagrams for explaining a process in which the transfer type step 103A is generated. FIG. 2A schematically shows a cross section of two film molds 102 adjacent to each other. When these film molds 102 are joined together, an overlapping portion 102A may occur at the boundary between them. FIG. 2B is an enlarged view of the overlapping portion 102A. Such an overlapping portion 102A may occur at the boundary of each set of two film molds 102 adjacent to each other. As shown in FIG. 2C, when the film mold 102 is joined and electroformed with a metal such as Ni, and the film mold 102 is peeled off, a transfer mold 103 as shown in FIG. 2D is obtained. The transfer mold 103 produced in this way has a transfer mold step 103A at a location corresponding to the joint of the film mold 102.

  FIG. 3 is a diagram illustrating a state where the transfer mold 103 illustrated in FIG. 2D is pressed against the transfer material 301 provided on the base material 302 using a roller 303. As shown in the drawing, when the transfer mold 103 having the transfer mold step 103A is used, a region 304 where the uneven shape on the surface of the transfer mold 103 is not reflected is generated in the transfer material 301. This is because air does not escape when the roller 303 is pressed against the transfer mold 103 due to the step 103A of the transfer mold formed along the direction perpendicular to the moving direction of the roller 303 (the direction perpendicular to the paper surface in FIG. 3). It is because it is trapped. As a result, the transfer material 103 is insufficiently filled into the transfer mold 103, and a region 304 in which the uneven shape is not formed correctly occurs.

  In the roll method, normally, the air accumulated in the concavo-convex structure can be released along with the flow of the transfer material 301. However, if there is a transfer mold step 103A, the width of the space between the transfer mold 103 and the substrate 302 changes sharply, so that air cannot be sufficiently released. When the transfer material 301 is cured in a state where the region 304 in which air is confined is present, a transfer product 305 having a transfer defect defect 301A is produced as shown in FIG.

  In order to prevent such a defective transfer defect 301A from occurring, for example, a method in which a plurality of film molds 102 are bonded after accurately aligning the transfer mold 103 so that the transfer mold step 103A does not occur. Can be considered. However, considering that the scale of the size handled by the imprint technique is on the order of nm to μm, such accurate alignment is not easy. In order to manufacture the transfer mold 103 having a large area and without the step 103A of the transfer mold without affecting the concavo-convex shape, a highly accurate alignment device is separately required, and the equipment cost for manufacturing the transfer mold 103 and The subject that man-hours increase arises.

  Based on the above findings, the inventor of the present application diligently studied a method that does not require high-precision alignment and realizes a large-area transfer by an imprint technique. As a result, by devising the height of the concavo-convex structure around the part where the step occurs, it is possible to effectively transfer the air staying between the transfer mold and the transfer material, and to produce a transfer product that is less prone to transfer defects It came to.

  Specifically, the inventor of the present application gradually changes the height of at least one of the concave and convex portions of the concavo-convex structure in the vicinity of the step of the transfer mold, and suppresses a steep change in the height of the transfer mold. It has been found that the air staying in the concavo-convex structure can be effectively released when pressed. As a result, the transfer material can be sufficiently filled around the stepped portion, and a transfer product in which transfer defects are hardly generated can be manufactured.

  An embodiment of the present disclosure devised by the inventor based on the above examination will be described below.

  First, an outline of an embodiment of the present disclosure will be described.

  (1) An imprint transfer according to an aspect of the present disclosure includes a base material and a concavo-convex structure formed on the base material. The concavo-convex structure has a first region and a second region adjacent to the first region and having an average remaining film thickness smaller than that of the first region. In the first region, the height of the plurality of irregularities in the portion adjacent to the second region is monotonously decreased in the direction from the first region toward the second region, or in the second region, the height The heights of the plurality of irregularities in the portion adjacent to the first region are monotonously decreasing in the direction from the second region toward the first region.

  (2) In one embodiment, the height of the plurality of projections and depressions in the portion close to the second region in the first region, and the plurality of portions in the portion close to the first region in the second region The height of the unevenness decreases monotonously in the direction from the first region to the second region.

  (3) In one embodiment, the height of the plurality of projections and depressions in the portion close to the second region in the first region, and the plurality of portions in the portion close to the first region in the second region The height of the unevenness decreases monotonously in the direction from the second region toward the first region.

  (4) In an embodiment, an inclined surface is formed at a boundary between the first region and the second region.

  (5) In a certain embodiment, each planar shape of the said 1st area | region and the said 2nd area | region is either a triangle, a square, and a hexagon.

  (6) In a certain embodiment, the height of each unevenness | corrugation in the said 1st area | region and the said 2nd area | region is in the range of 0.4 micrometer-2 micrometers.

  (7) In a certain embodiment, the pitch of the unevenness | corrugation in the said 1st area | region and the said 2nd area | region exists in the range of 0.6 micrometer-2.2 micrometers.

  (8) In one embodiment, the difference between the remaining film thickness of the portion closest to the second region in the first region and the remaining film thickness of the portion closest to the first region in the second region is 3 μm or less. It is.

  (9) In a certain embodiment, the said base material and the said uneven structure are formed of the translucent material.

  (10) In one embodiment, the substrate is formed using at least one of silicon, quartz, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, cyclic olefin polymer, polydimethylsiloxane, polyimide, and silicon resin. ing.

  (11) In one embodiment, the concavo-convex structure is formed using at least one of thermosetting resin, UV curable resin, metal paste, sol-gel solution, organometallic solution, hydrogen silsesquioxane, and room temperature curable glass. ing.

  (12) In one embodiment, the uneven structure includes a diffraction grating structure in which a plurality of concave portions and a plurality of convex portions are periodically arranged in a two-dimensional manner, or a plurality of concave portions and a plurality of convex portions each having a stripe shape. It has a structure periodically arranged in one dimension.

  (13) In an embodiment, the concavo-convex structure has a structure in which a plurality of concave portions and a plurality of convex portions are arranged in a two-dimensional random pattern.

  (14) In one embodiment, when the minimum value of the short side of the ellipse inscribed in each of the plurality of concave portions and the plurality of convex portions is w, the spatial frequency component of the pattern of the concave-convex structure Among them, a component smaller than 1 / (2w) is suppressed as compared with the case where the plurality of concave portions and the plurality of convex portions are arranged at random.

  (15) In an embodiment, the concavo-convex structure is configured such that a predetermined number or more of recesses or protrusions do not continue in one direction.

  (16) In an embodiment, a cross-sectional shape when cutting each of the plurality of recesses and the plurality of projections on a plane parallel to an array surface of the plurality of recesses and the plurality of projections is a quadrangle, The concavo-convex structure is configured such that three or more concave portions or convex portions are not continuous in the arrangement direction.

  (17) In an embodiment, a cross-sectional shape when the plurality of recesses and the plurality of projections are cut in a plane parallel to an array surface of the plurality of recesses and the plurality of projections is a hexagonal shape. The concavo-convex structure is configured such that four or more concave portions or convex portions are not continuous in the arrangement direction.

  (18) An imprint transfer mold according to another aspect of the present disclosure is an imprint transfer mold used for producing any of the above imprint transfer products, and includes a first region and the first region. And a concavo-convex structure having a second region having an average thickness larger than that of the first region. In the first region, the height of the plurality of irregularities in the portion adjacent to the second region is monotonously decreased in the direction from the first region toward the second region, or in the second region, the height The heights of the plurality of irregularities in the portion adjacent to the first region are monotonously decreasing in the direction from the second region toward the first region.

  (19) In one embodiment, the uneven structure has at least one of silicon, quartz, glass, diamond, silicon carbide, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, cyclic olefin polymer, polydimethylsiloxane, polyimide, and silicon resin. It is formed using one.

  (20) A method according to another aspect of the present disclosure is a method of producing an imprint transfer product using any of the above imprint transfer molds, wherein the imprint transfer mold is applied to a transfer material on a substrate. , A step of curing the transfer material, and a step of peeling the imprint transfer mold from the transfer material.

  Hereinafter, a more specific embodiment of the present disclosure will be described with reference to FIG. In the accompanying drawings, the dimensions and shapes of the constituent elements do not necessarily accurately represent actual dimensions and shapes. In order to facilitate understanding, specific dimensions and shapes may be highlighted.

(Embodiment 1)
Embodiment 1 relates to a transfer product having a concavo-convex structure in which the height of a convex portion varies depending on the position, and a transfer mold for producing such a transfer product. Here, “the height of the unevenness” means a difference in height between the adjacent concave and convex portions.

FIG. 5 is a diagram schematically showing a process of manufacturing the transfer mold 503 in the present embodiment. This step is basically the same as the step described with reference to FIG. 1, but differs in that the height of the unevenness formed on the original plate 501 shown in FIG. 5A is not uniform. Specifically, as shown in FIG. 6, the original plate 501 has a shape in which the height of the convex portion is constant and the height of the concave portion decreases toward the right side in FIG. 6. Accordingly, the height of the unevenness in the original 501 is higher toward the right side in FIG. The original plate 501 can be manufactured by forming irregularities on a substrate formed of quartz (SiO ₂ ) or the like by a method such as dry etching. As shown in the drawing, in order to make the height of the unevenness non-uniform, the thickness of the resist may be changed depending on the position and the etching depth may be made non-uniform when the original 501 is manufactured.

  In order to produce the transfer mold 503 shown in FIG. 5D, first, a plurality of film molds 502 are produced as shown in FIG. 5B by transferring the concavo-convex shape from the original 501 to the film. On the surface of each film mold 502, a concavo-convex structure in which the concavo-convex shape is inverted with respect to the shape shown in FIG. 6 is formed. Subsequently, as shown in FIG. 5 (c), a plurality of film molds 502 are joined together to produce an aggregate of large-area film molds 502. By performing electroforming using this film-type assembly as a mold and a metal such as Ni, a large-area imprint transfer mold 503 shown in FIG. 5D can be produced. The transfer mold 503 thus manufactured is a combination of a plurality of regions having the same concavo-convex shape as in FIG.

  The transfer mold 503 has a step at a portion corresponding to a place where the film molds 102 are connected to each other. 7A to 7D are diagrams for explaining a process in which a step is generated. FIG. 7A is a cross-sectional view schematically showing two film molds 502 adjacent to each other. When these film molds 502 are joined together, a height shift may occur at the boundary between them. In the above description (FIG. 2A), it is assumed that the overlapping portion 102A is generated in the two film molds 102. However, here, as shown in FIG. 7A, the two film molds 502 have a step without overlapping. The case where it is joined to is assumed. FIG. 7B is an enlarged view of a portion 502A where a height shift has occurred. Such misalignment can occur at the boundaries of each set of two film molds 502 adjacent to each other. As shown in FIG. 7C, when the film mold 502 is used for electroforming with a metal such as Ni and the film mold 502 is peeled off, a transfer mold 503 shown in FIG. 7D is obtained.

  The transfer mold 503 thus manufactured has a transfer mold first area 503a and a transfer mold second area 503b having different average thicknesses at a boundary corresponding to the joint of the film mold 502. In the transfer mold first area 503a, the heights of the plurality of irregularities in the vicinity of the transfer mold second area 503b monotonously decrease in the direction from the transfer mold first area 503a to the transfer mold second area 503b. doing. Further, the height of the plurality of projections and depressions in the portion adjacent to the transfer mold first area 503a in the transfer mold second area 503b is monotonous in the direction from the transfer mold second area 503b to the transfer mold first area 503a. Has increased. With such a structure, the gap between the transfer mold first area 503a closest to the transfer mold second area 503b and the transfer mold second area 503b closest to the transfer mold first area 503a. The height difference is relaxed, and air is easily released when pressed.

  FIG. 8 illustrates a transfer material 701 (for example, a thermosetting resin or a UV curable resin) provided on a base material 702 formed of glass or the like using a roller 703 using the transfer mold 503 shown in FIG. 7D. It is a figure which shows the condition currently pressed. In order to allow air between the transfer mold 503 and the transfer material 701 to escape and facilitate the filling of the transfer material 701, the roller 703 is assumed to travel on the surface of the transfer mold 503 in the direction from right to left in FIG. As described above, when the roll-type imprint is performed using the transfer mold 503, the transfer material can be filled in the vicinity of the step portion 701A at the time of pressing. As a result, when the transfer mold 503 is peeled after the transfer material 701 is cured with heat or UV light, a transfer product 705 with reduced generation of transfer defects as shown in FIG. 9 can be manufactured.

  The transfer product 705 thus manufactured includes a base material 702 and a concavo-convex structure made of a transfer material 701 formed on the base material 702. This concavo-convex structure has a first region 701a of the transferred material and a second region 701b of the transferred material. The second region 701b of the transferred material is adjacent to the first region 701a of the transferred material, and has an average remaining film thickness (average thickness of a portion excluding a plurality of convex portions from the transferred material 701). A) is small. In the first region 701a of the transcript, the height of the plurality of irregularities in the portion adjacent to the second region 701b of the transcript monotonously decreases in the direction from the first region 701a of the transcript toward the second region 701b of the transcript. doing. In addition, the height of the plurality of irregularities in the portion of the second region 701b of the transfer that is close to the first region 701a of the transfer is also in the direction from the first region 701a of the transfer toward the second region 701b of the transfer. It is decreasing monotonously.

  In the present embodiment, as shown in FIG. 5C, the four film molds 502 are joined to form a square aggregate, but the present disclosure is not limited to such an example. The number of film molds 102 and the manner of bonding may be appropriately determined according to the size and shape of the transfer product to be produced. Further, in order to make the unevenness of the transfer mold 503 uneven, the heating temperature is increased within the film plane when the film mold 502 is produced instead of the method of making the unevenness of the unevenness of the original 501 uneven. May be biased. In consideration of processing accuracy, a portion where the height of the concavo-convex structure is changed may be limited to a specific range. For example, the height of the concavo-convex structure may be changed within a range of 100 μm or less on both sides of the boundary between the transfer mold first region 503a and the transfer mold second region 503b in the transfer mold 503.

  In the present embodiment, the bonding shown in FIG. 7A is assumed as a method of bonding the film mold 502, but this is an example. For example, there may be a joint as shown in FIG. 10A. In this example, similar to the situation shown in FIG. 2A, the overlapping portion 502 </ b> A is generated between the two film molds 502. FIG. 10B is an enlarged view showing the overlapping portion 502A. When electroforming is performed using such an assembly of film molds 502 as shown in FIG. 10C, a transfer mold 503 shown in FIG. 10D is obtained. Even in such a transfer mold 503, since the height of the unevenness in the first area 503a of the transfer mold is suppressed to be low in the vicinity of the step, the same effect as described above can be obtained. As shown in FIG. 11, when the transfer material 701 is pressed by the transfer mold 503 using the roller 703, the transfer material 701 is cured, and the transfer mold 503 is peeled off, a transfer product 705 shown in FIG. 12 is obtained. This transfer product 705 also has a structure similar to the transfer product 705 shown in FIG.

  In the present embodiment, a metal such as Ni is exemplified as the material of the transfer mold 503, but is not limited thereto. For example, silicon (Si), quartz, glass, diamond, silicon carbide (SiC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polycarbonate (PC), cyclic olefin polymer (COP), polydimethylsiloxane ( The transfer mold 503 may be formed using at least one of PDMS), polyimide (PI), and silicon resin.

  Moreover, in this embodiment, although glass was illustrated as a material of the base material 702, it is not limited to this. For example, the substrate 702 may be formed using at least one of Si, quartz, PET, PMMA, PC, COP, PDMS, PI, and silicon resin.

  In this embodiment, a thermosetting resin or a UV curable resin is used as the transfer material 701, but the transfer material 701 is not limited thereto. For example, at least one of a metal paste, a sol-gel solution, an organometallic solution, hydrogen silsesquioxane (HSQ), and room temperature cured glass may be used as the transfer material 701.

(Embodiment 2)
Embodiment 2 relates to a transfer product having a concavo-convex structure in which the height of the recesses differs depending on the position, and a transfer mold for producing such a transfer product. Hereinafter, the description will focus on the points different from the first embodiment, and description of common matters will be omitted.

  FIG. 13 is a diagram schematically showing a process of manufacturing the transfer mold 904 in the present embodiment. This step is different from the step shown in FIG. 5 of Embodiment 1 in that the transfer to the film mold is performed twice. The original plate 501 shown in FIG. 13A and the film mold 502 shown in FIG. 13B are the same as those in the first embodiment. In the present embodiment, the film mold 502 is further transferred as a mold to produce a plurality of film molds 903 shown in FIG. Similar to the shape shown in FIG. 6, the surface of each film mold 903 has a concavo-convex structure in which the height of the convex portions is constant and the height of the concave portions varies depending on the position. Subsequently, as shown in FIG. 13 (d), a plurality of film molds 903 are joined together to produce a large-area film mold assembly. By performing electroforming using this film mold assembly as a mold and a metal such as Ni, a large-area imprint transfer mold 904 shown in FIG. 13E can be manufactured. The transfer mold 904 manufactured in this manner is a combination of a plurality of regions having shapes in which the irregularities are inverted with respect to the shapes shown in FIGS. 6 and 7D. That is, each region of the transfer mold 904 has a structure in which the height of the concave portion is constant and the height of the convex portion varies depending on the position.

  FIG. 14A is a cross-sectional view schematically showing a state where transfer is performed to a transfer material 1001 on a substrate 1002 using a transfer mold 904. In the present embodiment, the height of the plurality of irregularities in the portion adjacent to the transfer mold second area 904b in the transfer mold first area 904a is directed from the transfer mold first area 904a to the transfer mold second area 904b. The direction is increasing monotonously. Further, the height of the plurality of irregularities in the portion adjacent to the transfer mold first area 904a in the transfer mold second area 904b is monotonous in the direction from the transfer mold second area 904b to the transfer mold first area 904a. Has decreased. With such a structure, the concave portion 904c closest to the transfer-type second region 904b in the transfer-type first region 904a and the convex portion 904d closest to the transfer-type first region 904a in the transfer-type second region 904b The height difference between the two is relaxed, and air can be easily released.

  Also in this embodiment, in order to allow the air between the transfer mold 904 and the transfer material 1001 to escape and to facilitate the filling of the transfer material 701, the roller runs on the surface of the transfer mold 904 from right to left in FIG. 14A. It shall be. As described above, when the roll-type imprint is performed using the transfer mold 904, the transfer material can be filled in the vicinity of the stepped portion at the time of pressing. As a result, when the transfer mold 904 is peeled after the transfer material 1001 is cured with heat or UV light, a transfer product 1005 with suppressed generation of transfer defects as shown in FIG. 14B can be manufactured.

  The transfer material 1005 thus manufactured includes a base material 1002 and a concavo-convex structure made of a transfer material 1001 formed on the base material 1002. This concavo-convex structure has a first region 1001a of the transferred material and a second region 1001b of the transferred material. The second region 1001b of the transcript is adjacent to the first region 1001a of the transcript, and has an average remaining film thickness (average thickness of a portion excluding a plurality of convex portions from the transfer material 1001). A) is small. In the first region 1001a of the transcript, the height of the plurality of irregularities in the portion adjacent to the second region 1001b of the transcript monotonously increases in the direction from the first region 1001a of the transcript toward the second region 1001b of the transcript. doing. On the other hand, in the second region 1001b of the transferred product, the height of the plurality of irregularities in the portion adjacent to the first region 1001a of the transferred product is in the direction from the second region 1001b of the transferred product toward the first region 1001a of the transferred product. It is decreasing monotonously.

(Embodiment 3)
In the third embodiment, an example will be described in which the transfer product produced in the first or second embodiment is used as a light extraction structure in a light emitting element such as an organic EL element. When using a transcription | transfer material for such a use, a base material and an uneven structure are formed with a translucent material. The height of the unevenness of the transferred material is not necessarily uniform as shown below. For this reason, it is possible to use, as the light extraction structure, a transfer product in which the height of the unevenness in the first and second embodiments differs depending on the position.

  A light emitting element is often provided with a light extraction structure in order to efficiently extract light generated from the light emitting material to the outside. FIG. 15A is a cross-sectional view schematically showing an example of such a light emitting element. The light-emitting element 1 is an organic EL element, and has a structure in which a reflective electrode 11, an organic light-emitting layer 12, a transparent electrode 13, a transparent substrate 14, a light extraction structure 15, and a transparent substrate 16 are stacked in this order. . The light extraction structure 15 has an uneven structure 151 on the surface.

  The light extraction structure 15 can be realized by a diffraction grating pattern as shown in FIG. 15B, for example. In the diffraction grating pattern shown in FIG. 15B, a plurality of concave portions (white portions in FIG. 15B) and a plurality of convex portions (black portions in FIG. 15B) are periodically arranged in two dimensions. By providing such a light extraction structure 15, a part of light incident at an incident angle exceeding the critical angle can be extracted outside without being totally reflected.

  In order to use the transfer product in Embodiment 1 or 2 as the light extraction structure 15 as described above, it is necessary to appropriately design the height and pitch (period) of the unevenness. Further, depending on the height of the step between the transfer mold regions, the transfer product may not be formed normally. Therefore, a preferable uneven height, pitch, and step height will be described.

<Height of uneven structure>
FIG. 16A is a graph showing the dependence of light extraction efficiency on the height of the concavo-convex structure. This graph shows the result of calculating the light extraction efficiency using the light extraction structure having the diffraction grating pattern shown in FIG. 15B, setting the height of the unevenness to 0.4 μm or more at which light diffraction occurs. As this result shows, even if the height of the concavo-convex structure changes in the range of 0.4 μm to 2 μm, the rate of change in light extraction efficiency is about 2%. Therefore, if irregularities having a height of 0.4 μm or more can be formed in the transferred material, even if the height is spatially changed within the above range, the optical characteristics are not significantly affected.

<Pitch of uneven structure>
FIG. 16B is a graph showing the dependence of the light extraction efficiency on the pitch of the concavo-convex structure. “Pitch” means an average value of the distance between two adjacent convex portions (or concave portions). FIG. 16B shows the result of calculating the light extraction efficiency with the height of the unevenness set to 0.8 μm in the diffraction grating pattern as shown in FIG. 15B. Even if the pitch of the concavo-convex structure changes in the range from 0.6 μm to 2.2 μm, the rate of change in light extraction efficiency is about 3%. Therefore, if the concavo-convex structure having a pitch of 0.6 μm or more can be formed in the transferred material, the optical characteristics are not significantly affected. Further, the pitch may vary spatially within the range of 0.6 μm to 2.2 μm. In addition, when using the uneven | corrugated structure which has a non-periodic pattern mentioned later, what is necessary is just to consider an average period as "pitch." The average period in various uneven patterns will be described later.

<Step height>
With respect to a transfer product having a concavo-convex structure, the possibility of transfer with respect to the height of the step and the height of the concavo-convex will be described.

  As shown in FIG. 17A, in the transfer mold 904 according to the second embodiment, the height of the step is x, the height of the convex portion with respect to the concave portion is y, and the width of the convex portion is z. FIG. 17B shows whether or not a transcription product can be produced when z is set to 1.5 μm and several transcription molds having different x and y are produced. In consideration of filling the uneven portion of the transfer material, the step height x is preferably higher than the uneven height y. From FIG. 17B, when x is 3 μm and y is within 2 μm, a transfer product can be prepared normally. However, when x and y exceed these values, resin filling becomes insufficient, and the uneven shape transfer is normal. It may not be possible.

(Other embodiments)
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments. Various modifications of these embodiments and forms constructed by combining components in different embodiments are also included in the present disclosure. Hereinafter, other embodiments will be exemplified.

<Configuration with inclined surface>
In the above embodiment, it has been described that the transfer product is produced by imprinting using a transfer mold in which a step in a direction perpendicular to the uneven arrangement surface is generated, but the present invention is not limited to such a structure. Even if an inclined surface is formed between the first region and the second region of the transfer mold, the same effect can be obtained. For example, as shown in FIG. 18A, a transfer having an inclined surface 1301A at the boundary between a transfer-type first region 1304a and a transfer-type second region 1304b where the height of the convex portion is constant and the height of the concave portion is not uniform. Imprinting may be performed using the mold 1304. As a result, as shown in FIG. 18B, the uneven structure having the inclined surface 1301A at the boundary between the first region 1301a of the transferred material and the second region 1301b of the transferred material while the height of the convex portion in the uneven structure changes. A transfer product 1305 formed on the base material 1302 is produced. Even if it is such a transfer object 1305, generation | occurrence | production of a transfer defect is suppressed and it can use suitably for various uses.

<Configuration having a portion where the uneven height does not change>
In the above-described embodiment, the configuration in which the height of the concave portion or the convex portion changes monotonously toward the step on both sides of the step of the transferred material is not limited to such a structure. For example, a transcript 1405 as shown in FIG. 19A may be produced. In this transferred product 1405, in the first region 1401a of the transferred product having a relatively large average remaining film thickness, the height of the unevenness increases as it approaches the second region 1401b of the transferred material, and the average remaining film thickness is relatively small. In the second region 1401b of the transferred material, a concavo-convex structure 1401 having a concavo-convex height of a constant value α is formed on the base material 1402. Even with such a transferred product 1405, the same effect as that of the above-described embodiment can be obtained. Contrary to this example, the height of the unevenness in the first region 1401a of the transfer product is made constant, and the height of the unevenness in the 1401b of the second region transfer product is made smaller as it approaches the first region 1401a of the transfer product. Good. Alternatively, a transcript 1505 as shown in FIG. 19B may be produced. In this example, the transferred material 1505 has a monotonous change in the height of the unevenness in a portion close to the boundary between the first region 1501a of the transferred material and the second region 1501b of the transferred material, but is separated from the boundary. In the portion, a concavo-convex structure in which the concavo-convex height is maintained at a constant value β is formed on the base material 1502. Even with such a structure, the same effect can be obtained.

  Not only these examples, but the uneven structure in the transfer product according to the present disclosure is such that the height of the plurality of unevenness in the portion close to the second region in the first region is monotonous in the direction from the first region toward the second region. It is only necessary that the height of the plurality of irregularities in the second region is close to the first region in the direction from the second region to the first region. In the first region, the height of the plurality of irregularities in the portion close to the second region decreases monotonously in the direction from the first region toward the second region, and in the portion close to the first region in the second region The structure in which the height of the plurality of irregularities is monotonously decreasing in the direction from the second region toward the first region may be employed. For example, for each region, a configuration in which the height of the unevenness is relatively low at the end portion and the height of the unevenness is relatively high in the central portion is conceivable. Even such a configuration is effective because a steep change in height between two adjacent regions can be suppressed.

<How to arrange transcription molds>
In the above-described embodiment, the transfer-type original plate is a quadrangle, but is not limited to this shape. For example, a triangular original plate may be used. 20A and 20B show an example in which a plurality of film molds 1601 produced from a triangular original plate are connected to form a film mold 1602 that is an aggregate of hexagonal film molds. 21A and 21B show an example in which a plurality of film molds 1701 produced from hexagonal masters are connected to form a film mold 1702 that is an aggregate of hexagonal film molds. Even if a transfer mold and a transfer product are produced from such a film-type assembly, the occurrence of transfer defects can be suppressed. In these examples, if imprinting is performed from the left to the right in FIGS. 20B and 21B, the air staying in the concavo-convex portion can be effectively released to facilitate the filling of the transfer material into the transfer mold. The transfer mold may be prepared so that the remaining film thickness of the transferred material is thinner on the left side and thicker on the right side.

<Uneven pattern>
In the above embodiment, the concavo-convex structure pattern is the diffraction grating pattern shown in FIG. 15B, but is not limited to this. For example, as shown in FIG. 22A, each has a structure (line and space) in which a plurality of stripe-shaped concave portions (white) and a plurality of convex portions (black) are arranged one-dimensionally periodically or randomly. May be. Moreover, as shown to FIG. 22B and FIG. 22C, the pattern which has randomness may be sufficient. Here, the “pattern having randomness” is not limited to a completely random pattern, but the same type of blocks (minimum unit of concave portions or convex portions) does not appear continuously more than a predetermined number of times in the uneven direction. Includes a structure in which randomness is suppressed. FIG. 22B shows a quadrangular cross-sectional shape when cutting each of the plurality of recesses and the plurality of projections on a plane parallel to the arrangement surface of the concavo-convex structure, and three or more recesses or projections are not continuous in the arrangement direction. An example of the adjusted pattern is shown. FIG. 22C shows a hexagonal cross-section when each of the plurality of concave portions and the plurality of convex portions is cut in a plane parallel to the arrangement surface of the concave-convex structure, and four or more concave portions or convex portions are continuous in the arrangement direction. An example of a pattern adjusted so as not to occur is shown. Here, the “arrangement direction” refers to the horizontal direction and the vertical direction in the example illustrated in FIG. 22B, and refers to three directions perpendicular to the hexagonal side in the example illustrated in FIG. 22C.

  In the structure in which randomness is suppressed as shown in FIGS. 22B and 22C, the light extraction efficiency can be increased as compared with a completely random structure. Here, “a structure in which randomness is suppressed” means a structure that is not a completely random structure but is adjusted so that the same type of blocks does not appear more than a predetermined number of times in one direction.

  Such suppression of large blocks can also be confirmed by Fourier transforming the pattern. “Fourier transform of the pattern” means that the height of the concave portion and the flat portion of the convex portion with respect to the reference surface is expressed as a two-dimensional function with respect to coordinates x and y in the array surface, and the two-dimensional function is Fourier transformed. means. FIG. 23 is a diagram showing the amplitude of the spatial frequency component by Fourier-transforming the pattern. FIG. 23 (a) shows the result in a pattern in which randomness is suppressed so that three or more blocks of the same type do not continue in the arrangement direction, and FIG. 23 (b) shows a completely random pattern (appearance of concave and convex portions). The results are shown at a probability of 1/2). The center of the distribution diagram on the right side of FIG. 23 represents a component having a spatial frequency of 0 (DC component). In this figure, the spatial frequency is displayed so as to increase from the center toward the outside. As understood from this figure, it is confirmed that the low frequency component is suppressed in the spatial frequency of the suppressed random pattern shown in FIG. 23 (a) as compared with the random pattern shown in FIG. 23 (b). it can. In particular, it can be seen that a component smaller than 1 / (2w) among the spatial frequency components is suppressed.

FIG. 24 is a diagram for explaining an average period in each of a pattern (a) in which two types of unit structures (blocks) having a width w are randomly arranged and a pattern (b) in which the unit structures are periodically arranged. In the random structure shown in FIG. 24A, the average period in the arrangement direction is 4w. On the other hand, in the periodic structure shown in FIG. 24 (b), the average period in the arrangement direction is 2w. Note that the average period w _exp when the blocks are arranged at random is obtained by the calculation shown in the balloon of FIG. That is, in the random structure shown in FIG. 24A, the probability that a concave portion or convex portion having a width w exists is ½, and the probability that a continuous concave portion or convex portion having a width 2w exists is (½). ² . In general terms, the probability that a continuous concave or convex portion having a width nw (n is an arbitrary natural number) exists in each of the x direction and the y direction is (1/2) ⁿ . Therefore, the average length w _{exp in} the x direction and the y direction of the same kind of structure (concave or convex) in the random concavo-convex structure is obtained as 2w by the following calculation.

  Since the average period is the sum of the average length of the concave portions and the average length of the convex portions, it is 4w.

  Even in a structure in which randomness is suppressed as shown in FIGS. 22B and 22C, the average period can be obtained in the same way as described above. FIG. 25 shows a method for obtaining the average period from the structure pattern. Here, for each of the horizontal direction and the vertical direction shown in FIG. 25, an ellipse (including a perfect circle) inscribed in a region composed of a group of consecutive unit structures of the same type is considered. The average value of the size of the white part in the lower diagram of FIG. 25 can be obtained by calculating the average value of the lengths of the axes of the ellipses inscribed in the white part. The same applies to the black part. A value obtained by adding these average values is defined as an average period.

  The uneven shape may not be a structure that stands vertically with respect to the arrangement surface, but may be a tapered shape, that is, a shape having an inclined surface. In addition, the concave portion and the convex portion may include a fine structure that is sufficiently smaller than their width and height.

  The imprint transfer product of the present disclosure can be applied to, for example, a flat panel display, a backlight for a liquid crystal display device, a light source for illumination, and a semiconductor device.

DESCRIPTION OF SYMBOLS 1 Light emitting element 11 Reflective electrode 12 Organic light emitting layer 13 Transparent electrode 14 Transparent substrate 15 Light extraction structure 16 Transparent substrate 101,501 Master 102,502,903,1601,1701,1702 Film type 103,503,904,1304 Transfer type 103A Transfer mold step 301, 701, 1001 Transfer material 301A Transfer defect defect 302, 702, 1002, 1302, 1402, 1502 Base material 303, 703 Roller 304 region 305, 705, 1005, 1305, 1405, 1505 Transfer material 503a, 904a 1304a Transfer-type first region 503b, 904b, 1304b Transfer-type second region 701a, 1001a, 1301a, 1401a, 1501a Transcript first region 701b, 1001b, 1301b, 1401b, 1501b Second region of transcript

Claims (20)

A substrate;
An uneven structure formed on the substrate;
With
The concavo-convex structure has a first region and a second region adjacent to the first region and having a smaller average remaining film thickness than the first region,
In the first region, the height of the plurality of irregularities in the portion close to the second region is monotonously decreasing in the direction from the first region to the second region, or
The heights of the plurality of irregularities in the part adjacent to the first region in the second region is decreased monotonically for direction from the second region to the first region,
The upper surface of the convex portion in the second region is lower than the upper surface of the convex portion in the first region,
Imprint transcript.   The heights of the plurality of irregularities in the portion close to the second region in the first region, and the heights of the plurality of irregularities in the portion close to the first region in the second region are The imprint transfer product according to claim 1, which monotonously decreases in a direction from the first region toward the second region.   The heights of the plurality of irregularities in the portion close to the second region in the first region, and the heights of the plurality of irregularities in the portion close to the first region in the second region are The imprint transfer product according to claim 1, wherein the imprint transfer product monotonously decreases in a direction from the second region toward the first region. Are pre Symbol inclined surface formed at a boundary between the first region and the second region, the imprint transcript according to any one of claims 1 to 3.   5. The imprinted transfer product according to claim 1, wherein the planar shape of each of the first region and the second region is any one of a triangle, a quadrangle, and a hexagon.   6. The imprinted transfer product according to claim 1, wherein the height of each unevenness in the first region and the second region is in a range of 0.4 μm to 2 μm.   The imprint transfer product according to any one of claims 1 to 6, wherein a pitch of the unevenness in the first region and the second region is in a range of 0.6 µm to 2.2 µm.   8. The difference between the remaining film thickness of the portion closest to the second region in the first region and the remaining film thickness of the portion closest to the first region in the second region is 3 μm or less. The imprint transfer product according to any one of the above.   The imprint transfer product according to any one of claims 1 to 8, wherein the base material and the concavo-convex structure are formed of a translucent material.   The base material is formed using at least one of silicon, quartz, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, cyclic olefin polymer, polydimethylsiloxane, polyimide, and silicon resin. The imprint transfer product according to any one of the above.   The uneven structure is formed using at least one of a thermosetting resin, a UV curable resin, a metal paste, a sol-gel solution, an organometallic solution, hydrogen silsesquioxane, and room temperature curable glass. The imprint transfer product according to any one of the above.   The concavo-convex structure has a diffraction grating structure in which a plurality of concave portions and a plurality of convex portions are periodically arranged in a two-dimensional manner, or a plurality of stripe-shaped concave portions and a plurality of convex portions that are each periodically arranged in a one-dimensional manner. The imprint transfer product according to claim 1, wherein the imprint transfer product has a structure.   The imprinted transfer product according to any one of claims 1 to 11, wherein the concavo-convex structure has a structure in which a plurality of concave portions and a plurality of convex portions are arranged in a two-dimensional random pattern.   When the minimum value of the short side of the ellipse inscribed in each of the plurality of concave portions and the plurality of convex portions is w, 1 / (2w) of the spatial frequency components of the pattern of the concavo-convex structure The imprinted transfer product according to claim 13, wherein a smaller component is suppressed as compared with a case where the plurality of concave portions and the plurality of convex portions are arranged at random.   The imprinted transfer product according to claim 14, wherein the concavo-convex structure is configured such that a predetermined number or more of recesses or protrusions do not continue in one direction.   The cross-sectional shape of each of the plurality of recesses and the plurality of projections cut in a plane parallel to the arrangement surface of the plurality of recesses and the plurality of projections is a quadrangle, and three or more recesses or projections The imprinted transfer product according to claim 15, wherein the concavo-convex structure is configured so as not to be continuous in the arrangement direction.   The cross-sectional shape when each of the plurality of recesses and the plurality of projections is cut in a plane parallel to the arrangement surface of the plurality of recesses and the plurality of projections is hexagonal, and four or more recesses or projections The imprint transfer product according to claim 15, wherein the concavo-convex structure is configured so that the portions do not continue in the arrangement direction. An imprint transfer mold used for producing the imprint transfer product according to any one of claims 1 to 17,
A concavo-convex structure having a first region and a second region adjacent to the first region and having an average thickness larger than that of the first region,
In the first region, the height of the plurality of irregularities in the portion close to the second region is monotonously decreasing in the direction from the first region to the second region, or
The heights of the plurality of irregularities in the part adjacent to the first region in the second region is decreased monotonically for direction from the second region to the first region,
The upper surface of the convex portion in the first region is lower than the upper surface of the convex portion in the second region,
Imprint transfer type.   The uneven structure is formed using at least one of silicon, quartz, glass, diamond, silicon carbide, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, cyclic olefin polymer, polydimethylsiloxane, polyimide, and silicon resin. The imprint transfer mold according to claim 18. A method for producing an imprint transfer using the imprint transfer mold according to claim 18, comprising:
Pressing the imprint transfer mold against a transfer material on a substrate;
Curing the transfer material;
Peeling the imprint transfer mold from the transfer material;
Including methods.

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