Imprint mold and manufacturing method therefor, and template set

Abstract

This imprint mold comprises: a base material that has a first surface and a second surface located on the opposite side therefrom; a relief pattern that is formed in a pattern region on the first surface side of the base material; and a relief structure for alignment that is formed in an alignment region on the first surface side of the base material. The imprint mold is used for transferring the relief pattern to an imprint resin which has been supplied onto a transfer-receiving substrate. The relief pattern has a recessed pattern and a protruding pattern. The relief structure for alignment has a recessed section and a protruding section. A first imaginary plane including a top section of the protruding section is located further to the second surface side than a second imaginary plane including a top section of the protruding pattern, to such an extent that during an imprint process using the imprint mold, the relief structure for alignment can be filled with the imprint resin.

Description

Imprint mold, method for manufacturing the same, and template set

[0001] The present disclosure relates to an imprint mold, a method for manufacturing the same, and a template set.

[0002] Nanoimprint technology, which is known as a microfabrication technology, is a pattern forming technology that uses an imprint mold having an uneven pattern formed on the surface of a base material to transfer the uneven pattern at equal magnification to a workpiece such as a transfer substrate. In particular, with the further miniaturization of wiring patterns and the like in semiconductor devices, nanoimprint technology has attracted attention as one means in the manufacturing processes and the like thereof.

[0003] In nanoimprint technology, an imprint mold having a fine uneven transfer pattern formed on a pattern surface is brought into contact with resin supplied to the surface of a transfer-receiving substrate such as a semiconductor wafer, thereby filling the transfer pattern with the resin, and then curing the resin in this state, thereby forming an uneven pattern in which the uneven shape of the transfer pattern of the imprint mold is transferred onto the resin. The uneven pattern formed on a transfer-receiving substrate using an imprint mold is used as it is as a part of constituent elements of a product, or is used for processing the transfer-receiving substrate and the like. Therefore, it is required that the uneven shape of the transfer pattern of the imprint mold is transferred to the resin with high precision.

[0004] Imprint molds are required to have pattern dimension stability, chemical resistance, processing characteristics, and the like. Since the shape of the transfer pattern of the imprint mold must be faithfully transferred to the resin, imprint molds are generally manufactured using quartz glass that transmits ultraviolet light used for photocuring.

[0005] In the exposure process of semiconductor device manufacturing, as element patterns become smaller, there is a need to improve the accuracy of alignment, which involves superimposing the upper element pattern onto the lower element pattern. Alignment is performed by measuring the arrangement of pattern layers already formed on the wafer, which is the substrate to be processed, and matching the shot position of the pattern layer to be exposed to the arrangement of pattern layers on the wafer. To enable such alignment, wafer alignment marks are formed on each shot belonging to the pattern layer on the wafer.

[0006] Known alignment methods include die-by-dye alignment and global alignment. Die-by-dye alignment is a method of aligning each shot to be exposed for each shot belonging to a specific pattern layer already formed on the wafer. Alignment marks formed on the shots of the specific pattern layer corresponding to the shot to be exposed are detected and their coordinates are measured, and the position of the shot to be exposed on the wafer is determined based on the measurement results. Alternatively, positional misalignment is detected by simultaneously detecting the alignment marks formed on each shot and the alignment marks formed on the imprint mold, and the exposure position is determined to minimize this misalignment. On the other hand, global alignment is an alignment method in which the alignment marks of multiple specific shots selected from all shots belonging to a specific pattern layer already formed on the wafer are detected, and the exposure position is determined based on the arrangement of the alignment marks. Die-by-dye alignment has the advantage of high alignment accuracy for each shot because alignment is performed for each shot, but it also has the disadvantage of a long total alignment time because many shots are often applied to a single wafer.

[0007] In the imprint method, global alignment makes it difficult to maintain the position of the imprint mold with high precision because force is applied to the imprint mold during the imprinting of each shot after alignment measurement, resulting in a decrease in alignment accuracy. Therefore, die-by-dialignment is used, and the imprint mold is provided with alignment marks for positioning along with the raised and recessed patterns to be transferred.

[0008] Japanese Patent Publication No. 2013-519236

[0009] Alignment between the imprint mold and the substrate is performed with resin filled between the imprint mold and the substrate. Substrates used in semiconductor manufacturing processes have predetermined spaces between adjacent shots, and alignment marks are formed in these spaces. If alignment is performed with resin filled between the alignment marks of the imprint mold and the substrate, detection of the alignment marks may become difficult if the refractive index difference between the imprint mold and the resin is minimal.

[0010] In the technology described in Patent Document 1, a film made of a high-contrast material is formed in the recesses of the alignment marks of the imprint mold, which has the effect of making the alignment marks easily detectable even when the recesses of the alignment marks are filled with imprint resin. On the other hand, in the imprint mold disclosed in Patent Document 1, the uneven pattern (the pattern to be transferred to the substrate to be processed) and the alignment marks are formed on the same plane. Therefore, when processing the substrate to be transferred using a pattern formed on the substrate to be transferred corresponding to the uneven pattern of the imprint mold, there is a problem that the substrate to be transferred is processed according to the pattern formed on the substrate to be transferred corresponding to the alignment marks.

[0011] In view of the above issues, this disclosure aims to provide an imprint mold capable of preventing the transfer substrate from being processed by a pattern formed according to an alignment-based uneven structure, a method for manufacturing the same, and a template set.

[0012] To achieve this objective, as one embodiment of the present disclosure, an imprint mold is provided which is used to transfer the uneven pattern to an imprint resin supplied onto a transfer substrate, comprising a substrate having a first surface and a second surface located opposite to the first surface, an uneven pattern formed in a pattern region on the first surface side of the substrate, and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the uneven pattern has a concave pattern and a convex pattern, and the alignment uneven structure has a concave portion and a convex portion, and when a first virtual plane including the top of the convex portion and a second virtual plane including the top of the convex pattern are defined, the first virtual plane is located on the second surface side of the second virtual plane, and the first virtual plane is located on the second surface side of the second virtual plane to the extent that the imprint resin can be filled into the alignment uneven structure during imprint processing using the imprint mold.

[0013] As one embodiment of the present disclosure, a method for manufacturing an imprint mold is provided, comprising a substrate having a first surface and a second surface located opposite to the first surface, an uneven pattern formed in a pattern region on the first surface side of the substrate, and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the method is used to transfer the uneven pattern onto an imprint resin supplied onto a transfer substrate, and includes the steps of: forming the uneven pattern in a pattern region set on the first surface of the substrate; forming recesses and protrusions in an alignment region set on the first surface of the substrate; and forming the alignment uneven structure having the recesses and protrusions by positioning the tops of the protrusions formed in the alignment region on the second surface side of the first surface, wherein the alignment uneven structure is formed to a depth such that the imprint resin can fill the alignment uneven structure during an imprint process using the imprint mold.

[0014] As one embodiment of the present disclosure, a template set is provided for manufacturing an imprint mold used to transfer the uneven pattern onto an imprint resin supplied onto a transfer substrate, the template set comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the alignment uneven structure of the imprint mold has a recessed structure provided on the first surface of the substrate and a recess and a protrusion formed on the bottom surface of the recessed structure, the template set comprises a first template and a second template, the first template having a first uneven structure corresponding to the uneven pattern and a second uneven structure corresponding to the recess and the protrusion, and the second template having a protrusion structure corresponding to the recess.

[0015] According to this disclosure, it is possible to provide an imprint mold capable of preventing the transfer substrate from being processed by a pattern formed according to the alignment uneven structure, a method for manufacturing the same, and a template set.

[0016] Figure 1 is a cross-sectional view showing a schematic configuration of an imprint mold according to an embodiment of the present disclosure. Figure 2A is a partially enlarged cross-sectional view showing a schematic configuration of an alignment surface in an embodiment of the present disclosure. Figure 2B is a partially enlarged cross-sectional view showing a schematic configuration of another aspect of the alignment surface in an embodiment of the present disclosure. Figure 2C is a partially enlarged cross-sectional view showing a schematic configuration of another aspect of the recess and protrusion of the alignment surface in an embodiment of the present disclosure. Figure 2D is a partially enlarged cross-sectional view illustrating potential problems that may occur when the imprint resin is not sufficiently filled into the alignment surface. Figure 2E is a schematic diagram showing image data used to calculate the radius of curvature of the corners of the protrusions in an embodiment of the present disclosure. Figure 3 is a plan view showing one aspect of the alignment surface in an embodiment of the present disclosure. Figure 4 is a plan view showing another aspect of the alignment surface in an embodiment of the present disclosure. Figure 5A is a cutaway view showing one step in the method for manufacturing an imprint mold according to an embodiment of the present disclosure. Figure 5B is a cutaway view showing one step in the method for manufacturing an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 5A. Figure 5C is a cutaway view showing one step in the method for manufacturing an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 5B. Figure 5D is a cutaway view showing one step in the method for manufacturing an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 5C. Figure 5E is a cutaway view showing one step in the method for manufacturing an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 5D. Figure 5F is a cutaway view showing one step in another embodiment of the method for manufacturing an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 5D. Figure 5G is a cutaway view showing one step in another embodiment of the method for manufacturing an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 5F. Figure 5H is a cross-section view showing a step in another embodiment of the method for manufacturing an imprint mold according to the present disclosure, which follows the step shown in Figure 5G.Figure 5I is a partially enlarged cross-section view illustrating the process of forming a high-contrast film on an alignment uneven structure in the process shown in Figure 5H. Figure 5J is a partially enlarged cross-section view illustrating the process of forming a high-contrast film on an alignment uneven structure in the process shown in Figure 5H, following the process shown in Figure 5I. Figure 6A is a cross-section view showing the schematic configuration of the first template of the template set in an embodiment of the present disclosure. Figure 6B is a cross-section view showing the schematic configuration of the second template of the template set in an embodiment of the present disclosure. Figure 7A is a cross-section view illustrating one step in a method of forming a first resist pattern, a second resist pattern, and a resist pattern used to form an uneven pattern and alignment uneven structure of an imprint mold in an embodiment of the present disclosure using a template set. Figure 7B is a cross-section view illustrating one step in a method of forming a first resist pattern, a second resist pattern, and a resist pattern used to form an uneven pattern and alignment uneven structure of an imprint mold in an embodiment of the present disclosure using a template set, following the process shown in Figure 7A. Figure 7C is a cross-section view showing a step in a method for forming a first resist pattern, a second resist pattern, and a resist pattern used to form the uneven pattern and alignment uneven structure of an imprint mold according to an embodiment of the present disclosure, using a template set, and following the step shown in Figure 7B. Figure 8A is a cross-section view showing a step in an imprint method using an imprint mold according to an embodiment of the present disclosure. Figure 8B is a cross-section view showing a step in an imprint method using an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 8A. Figure 8C is a cross-section view showing a step in an imprint method using an imprint mold according to an embodiment of the present disclosure, following the step shown in Figure 8B. Figure 9 is a cross-section view showing a schematic configuration of a transfer substrate processed using a main transfer pattern formed by an imprint mold according to an embodiment of the present disclosure.

[0017] Embodiments of this disclosure will be described with reference to the drawings. In these drawings, the shape, scale, aspect ratio of each part may be altered or exaggerated from the actual object in order to facilitate understanding. In this specification, a numerical range expressed using "~" means a range that includes the numbers written before and after "~" as the lower limit and upper limit, respectively. In this specification, a numerical range expressed using "~" means a range that includes the numbers written before and after "~" as the lower limit and upper limit, respectively. For example, a numerical range defined by the expression "10 nm to 100 nm" is the same as a numerical range defined by "10 nm or more and 100 nm or less". In this specification, terms such as "film," "sheet," and "plate" are not distinguished from each other based on differences in designation. For example, "plate" is a concept that also includes components that can be generally called "sheets" or "films."

[0018] A first aspect of this disclosure is an imprint mold used to transfer the uneven pattern to an imprint resin supplied onto a transfer substrate, comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the uneven pattern has a concave pattern and a convex pattern; the alignment uneven structure has a concave portion and a convex portion; and when a first virtual plane including the top of the convex portion and a second virtual plane including the top of the convex pattern are defined, the first virtual plane is located on the second surface side of the second virtual plane, and the first virtual plane is located on the second surface side of the second virtual plane to the extent that the imprint resin can be filled into the alignment uneven structure during an imprint process using the imprint mold.

[0019] A second aspect of this disclosure is an imprint mold in which, in the first aspect, the first virtual plane and the second virtual plane are planes substantially parallel to the first surface, and the length between the first virtual plane and the second virtual plane along the thickness direction of the substrate is 10 nm to 100 nm.

[0020] A third aspect of this disclosure is an imprint mold in which, in the first or second aspect, a high-contrast film is provided on the bottom surface of the recess of the alignment uneven structure, the film being made of a material different from the material constituting the substrate and having optical properties different from those of the substrate.

[0021] A fourth aspect of this disclosure is, in the third aspect described above, an imprint mold provided continuously on the bottom and side surfaces of the recesses of the alignment uneven structure.

[0022] A fifth aspect of this disclosure is an imprint mold in which, in the fourth aspect described above, the thickness of the high-contrast film located near the bottom surface among the high-contrast films provided along the side surface is thicker than the thickness of the high-cottonlast film provided at the end of the side surface.

[0023] A sixth aspect of this disclosure is an imprint mold in which, in the third aspect described above, the film thickness of the high-contrast film is less than or equal to the depth of the recess of the alignment uneven structure.

[0024] A seventh aspect of this disclosure is an imprint mold in which the thickness of the high-contrast film is 1 nm to 50 nm, in the third or fourth aspect described above.

[0025] An eighth aspect of this disclosure is that, in any of the first to seventh aspects, the alignment uneven structure is an imprint mold provided adjacent to the uneven pattern.

[0026] A ninth aspect of this disclosure is an imprint mold having, in any of the first to eighth aspects, a recessed structure for alignment, a recessed structure, and the recessed portion and the protruding portion provided on the bottom surface of the recessed structure.

[0027] A tenth aspect of this disclosure is an imprint mold in which, in a plan view from the first surface side of the substrate, the length between the recess closest to the outer edge of the recessed structure and the outer edge of the recessed structure is 1 μm or more.

[0028] An eleventh aspect of this disclosure is an imprint mold in which, in any of the first to tenth aspects, the width of the recess of the alignment uneven structure is 0.8 μm or less.

[0029] A twelfth aspect of this disclosure is an imprint mold in which, in any of the third to seventh aspects described above, the width of the recess of the alignment uneven structure is 0.1 μm or more.

[0030] A thirteenth aspect of this disclosure is an imprint mold in which, in the eleventh aspect described above, the radius of curvature of the corners of the protrusions of the alignment uneven structure is 7 nm to 25 nm in a cross-sectional view along the thickness direction of the substrate.

[0031] A fourteenth aspect of this disclosure is a method for manufacturing an imprint mold used to transfer the uneven pattern to an imprint resin supplied onto a transfer substrate, comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, the method comprising: forming the uneven pattern in a pattern region set on the first surface of the substrate; forming recesses and protrusions in an alignment region set on the first surface of the substrate; and forming the alignment uneven structure having the recesses and protrusions by positioning the tops of the protrusions formed in the alignment region on the second surface side of the first surface, wherein the alignment uneven structure is formed to a depth such that the imprint resin can fill the alignment uneven structure during an imprint process using the imprint mold.

[0032] A 15th aspect of this disclosure is a method for manufacturing an imprint mold in which, in the step of forming the alignment uneven structure described in the 14th aspect, a resist pattern having a recessed pattern that exposes the recesses and protrusions formed in the alignment region is formed, and the first surface of the substrate is etched using the resist pattern as a mask to form the alignment uneven structure.

[0033] A sixteenth aspect of this disclosure is a method for manufacturing an imprint mold, wherein, in the fourteenth or fifteenth aspect, a first resist pattern corresponding to the uneven pattern is formed in the pattern region, a second resist pattern corresponding to the recesses and protrusions is formed in the alignment region, and the first surface of the substrate is etched using the first resist pattern and the second resist pattern as a mask to form the uneven pattern, as well as the recesses and protrusions.

[0034] A 17th aspect of this disclosure is a method for manufacturing an imprint mold in which a resist pattern is formed by an imprint process using a template having a convex structure corresponding to the concave pattern of the resist pattern, in the 15th aspect described above.

[0035] A 18th aspect of this disclosure is a method for manufacturing an imprint mold in which the first resist pattern and the second resist pattern are formed by an imprint process using a template having an uneven structure corresponding to the first resist pattern and an uneven structure corresponding to the second resist pattern, in accordance with the 16th aspect.

[0036] A 19th aspect of this disclosure is a method for manufacturing an imprint mold, which includes a step of forming a high-contrast film on the bottom surface of the recess of the alignment uneven structure, in any of the 14th to 18th aspects described above.

[0037] A 20th aspect of the present disclosure is a template set used to manufacture an imprint mold used to transfer the uneven pattern onto an imprint resin supplied onto a transfer substrate, the template set comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the alignment uneven structure of the imprint mold has a recessed structure provided on the first surface of the substrate and recesses and protrusions formed on the bottom surface of the recessed structure, the template set comprising a first template and a second template, the first template having a first uneven structure corresponding to the uneven pattern and a second uneven structure corresponding to the recesses and protrusions, and the second template having a protrusion structure corresponding to the recessed structure.

[0038] [Imprint Mold] The imprint mold 1 according to this embodiment comprises a base material 2 having a first surface 21 and a second surface 22 located on the opposite side of the first surface 21, an uneven pattern 3 formed in the pattern region PA on the first surface 21 side of the base material 2, and an alignment uneven structure 4 formed in the alignment region AA on the first surface 21 side of the base material 2 (see Figures 1, 2A, and 2B).

[0039] The base material 2 is a general base material for imprint molds, and examples thereof include glass substrates such as quartz glass substrates, soda glass substrates, fluorite substrates, calcium fluoride substrates, magnesium fluoride substrates, alkali-free glass substrates such as barium borosilicate glass, alumino borosilicate glass, and alumino silicate glass; resin substrates such as polycarbonate substrates, polypropylene substrates, polyethylene substrates, polymethyl methacrylate substrates, and polyethylene terephthalate substrates; semiconductor substrates such as silicon substrates and gallium nitride substrates; and laminated substrates formed by laminating two or more substrates arbitrarily selected from the above, and it is preferable to use a transparent substrate or the like. In the present embodiment, "transparent" means capable of transmitting light having a wavelength that can cure the imprint resin, and means that the transmittance for light with a wavelength of 160 nm to 400 nm is 60% or more, preferably 90% or more, and particularly preferably 95% or more.

[0040] The shape of the base material 2 in plan view is not particularly limited, and examples thereof include a substantially rectangular shape. When the base material 2 is a quartz glass substrate generally used for optical imprinting, the shape of the base material 2 in plan view is usually substantially rectangular.

[0041] The size of the base material 2 (the size in plan view) is also not particularly limited, but when the base material 2 is the above quartz glass substrate, for example, the size of the base material 2 is approximately 152 mm × 152 mm. In addition, the thickness of the base material 2 can be appropriately set, for example, in the range of approximately 300 μm to 10 mm in consideration of strength, handling suitability and the like.

[0042] The uneven pattern 3 formed in the pattern region PA has a recessed pattern 31 and a raised pattern 32. The shape, dimensions, etc. of the uneven pattern 3 can be appropriately set according to the shape, dimensions, etc. required for the product manufactured using the imprint mold 1 according to this embodiment. For example, the shape of the uneven pattern 3 can be a line and space shape, a pillar shape, a hole shape, a grid shape, a staircase shape, etc. The dimensions of the uneven pattern 3 can be set to, for example, about 10 nm to 500 nm. The dimensions of the uneven pattern 3 are defined by the shape of the uneven pattern 3. For example, the dimensions of the uneven pattern 3 are as follows: if the shape of the uneven pattern 3 is line and space, it is the length in the shorter direction (width direction) of the space-shaped recessed pattern 31 or the line-shaped convex pattern 32; if the shape of the uneven pattern 3 is pillar-shaped, it is the diameter or diagonal length of the pillar-shaped convex pattern 32; if the shape of the uneven pattern 3 is hole-shaped, it is the diameter or diagonal length of the hole-shaped recessed pattern 31; if the shape of the uneven pattern 3 is grid-shaped, it is the length in the shorter direction (width direction) of the grid-shaped recessed pattern 31 or convex pattern 32; and if the shape of the uneven pattern 3 is staircase-shaped, it is the length in the shorter direction of the tread of each step of the staircase-shaped recessed pattern 31 or convex pattern 32.

[0043] When viewing a cross-section along the thickness direction of the substrate 2, the angle of the side wall of the convex pattern 32 with respect to the bottom surface of the concave pattern 31 (the rising angle of the convex pattern 32) is preferably less than 90°, and particularly preferably between 85° and 89°. In other words, the cross-sectional shape of the convex pattern 32 is preferably tapered. Since the angle of the side wall of the convex pattern 32 is less than 90° and the cross-sectional shape of the convex pattern 32 is tapered, the mechanical strength of the convex pattern 32 can be improved, thereby preventing damage to the convex and concave pattern 3 caused by foreign matter or the like when foreign matter or the like is present on the transfer substrate 90 (see Figure 8A, etc.) during the imprint process using the imprint mold 1.

[0044] The alignment uneven structure 4 formed in the alignment area AA has a recess 41 and a protrusion 42. The dimensions of the recess 41 and the protrusion 42 only need to be such a degree that enables alignment between the imprint mold 1 and the transfer target substrate 90 (see FIG. 8A and the like), and may be, for example, about 100 nm to 3 μm. Note that the dimensions of the recess 41 and the protrusion 42 may be different from the dimensions of the uneven pattern 3 formed in the pattern area PA, or may be substantially the same.

[0045] The shapes (shapes in plan view) of the recess 41 and the protrusion 42 of the alignment uneven structure 4 are not particularly limited, and may be determined in consideration of, for example, the shape of the alignment mark 93 formed on the transfer target substrate 90 on which imprint processing using the imprint mold 1 according to the present embodiment is performed. For example, the plan view shapes of the recess 41 and the protrusion 42 of the alignment uneven structure 4 may be a lattice shape (see FIG. 3) or a line-and-space shape (see FIG. 4).

[0046] In the imprint mold 1 according to this embodiment, a first virtual plane VP1 is defined that includes the top 421 of the convex portion 42 of the alignment uneven structure 4, and a second virtual plane VP2 is defined that includes the top 321 of the convex pattern 32 of the uneven pattern 3. Both the first virtual plane VP1 and the second virtual plane VP2 are planes substantially parallel to the first surface 21. "Substantially parallel" means that the angle with the first surface 21 is 5° or less. In this embodiment, the top 321 of the convex pattern 32 of the uneven pattern 3 is located on the same plane as the first surface 21 of the base material 2. That is, the second virtual plane VP2 includes the first surface 21 of the base material 2. At this time, the first virtual plane VP1 should be located on the second surface 22 side of the second virtual plane VP2 to the extent that the imprint resin 94 can be filled into the alignment uneven structure 4 during the imprint process using the imprint mold 1. Specifically, the length between the first virtual plane VP1 and the second virtual plane VP2 (length along the thickness direction of the substrate 2), that is, the depth D43 of the recessed structure 43 of the alignment uneven structure 4, is preferably 10 nm to 100 nm, and more preferably 15 nm to 80 nm. By positioning the first virtual plane VP1 on the second surface 22 side of the second virtual plane VP2, that is, by positioning the top 421 of the convex portion 42 of the alignment uneven structure 4 on the second surface 22 side of the first surface 21, when processing the substrate 90 using the main transfer pattern 96 formed on the substrate 90 by an imprint process using the imprint mold 1, a resist pattern is formed in the scribed area of ​​the substrate 90 corresponding to the alignment uneven structure 4, thereby preventing the scribed area from being processed.Furthermore, if the length D43 between the first virtual plane VP1 and the second virtual plane VP2 is less than 10 nm, the thickness of the resist pattern 97 formed in correspondence with the alignment uneven structure 4 may be insufficient, and there is a risk that the scribe area on the transfer substrate 90 may be processed. If the length D43 exceeds 100 nm, there is a risk that the imprint resin 94 may not be sufficiently filled into the alignment uneven structure 4 during the imprint process using the imprint mold 1, and the resist pattern 97 formed in correspondence with the alignment uneven structure 4 may break, causing defects, or the shape of the resist pattern 97 may become uneven, which may result in the scribe area on the transfer substrate 90 being processed. In addition, the formation accuracy of the alignment uneven structure 4 may decrease, and as a result, the alignment accuracy may decrease.

[0047] In this embodiment, the alignment uneven structure 4 has a recessed structure 43 formed on the first surface 21 of the base material 2, and the recessed portion 41 and the convex portion 42 only need to be formed on the bottom surface 431 of the recessed structure 43. As will be described later, the recessed portion 41 and the convex portion 42 of the alignment uneven structure 4 can be formed in the same process as the uneven pattern 3 when manufacturing the imprint mold 1 according to this embodiment (see Figure 5B). At the stage where they are formed in the same process as the uneven pattern 3, the top portion 421 of the convex portion 42 of the alignment uneven structure 4 is located on the same plane as the top portion 321 of the convex pattern 32 of the uneven pattern 3. Therefore, because the alignment uneven structure 4 has a recessed structure 43, even if the recessed portion 41 and the convex portion 42 of the alignment uneven structure 4 are formed in the same process as the uneven pattern 3, the top portion 421 of the convex portion 42 can be positioned on the second surface 22 side of the first surface 21, and the imprint mold 1 can be manufactured efficiently.

[0048] In a plan view from the first surface 21 side of the substrate 2, the length L43 between the nearest recess 41 to the outer edge 432 of the recessed structure 43 and the outer edge 432 of the recessed structure 43 should be 1 μm or more, and may be between 1 μm and 20 μm. Having a length L43 of 1 μm or more prevents stray light unnecessary for alignment from entering from the outer edge 432 during alignment of the imprint mold 1 and the transfer substrate 90, thus preventing a decrease in detection accuracy. The length L43 should be the length between the nearest recess 41 and the outer edge 432 in a direction perpendicular to each side of the outer edge 432, which is approximately rectangular in plan view.

[0049] A high-contrast film 5 is provided on the bottom surface of the recess 41 of the alignment uneven structure 4. This film is made of a material different from the material constituting the base material 2 and has optical properties different from the optical properties (transmittance and reflectance) of the base material 2. The alignment uneven structure 4 is provided adjacent to the uneven pattern 3. The alignment uneven structure 4 is used for alignment by imprinting using the imprint mold 1, utilizing the alignment marks 93 formed corresponding to each shot area of ​​the transfer substrate 90 (see Figure 8A, etc.). Therefore, if the alignment uneven structure 4 is provided at a position far from the uneven pattern 3, alignment with respect to each shot area of ​​the transfer substrate 90 may become difficult, and the imprint resin may not adequately fill the alignment uneven structure 4 during imprinting. On the other hand, by providing the alignment uneven structure 4 adjacent to the uneven pattern 3, the imprint resin between each shot area of ​​the transfer substrate 90 and the uneven pattern 3 can adequately fill the alignment uneven structure 4. When the alignment-oriented uneven structure 4 is filled with imprint resin, the refractive index difference between the substrate 2 of the imprint mold 1 and the imprint resin becomes small, making it difficult to detect the alignment-oriented uneven structure 4 and thus difficult to align. In this embodiment, a high-contrast film 5 is provided on the bottom surface of the recess 41 of the alignment-oriented uneven structure 4, so that alignment can be easily performed even when the alignment-oriented uneven structure 4 is filled with imprint resin.

[0050] Furthermore, the contrast of the recesses 41 of the alignment uneven structure 4 with respect to the substrate 2 is a concept that includes not only the difference in optical properties (transmittance and reflectance) when the optical properties (transmittance and reflectance) of the recesses 41 of the alignment uneven structure 4 differ from those of the substrate 2, but also the difference in optical properties (transmittance and reflectance) when the optical properties (transmittance and reflectance) of both are the same (the difference in transmittance and reflectance is zero). The same optical properties of both include cases where the optical properties of both are so different that it is difficult or impossible to detect the recesses 41 of the alignment uneven structure 4 in the optical system of the alignment device.

[0051] The material constituting the high-contrast film 5 (high-contrast material) is not particularly limited, but it is sufficient that it is different from the material constituting the substrate 2, and that it is a material capable of forming a high-contrast film 5 having different optical properties such as transmittance and reflectance compared to the substrate 2. Preferably, the high-contrast material is a material in which the contrast of the high-contrast film 5 with respect to the substrate 2 is higher than the contrast of the recesses 41 of the alignment uneven structure 4 with respect to the substrate 2. For example, one or more metal materials and their oxides, nitrides, oxynitrides can be cited. Specific examples of metal materials include, for example, chromium (Cr), molybdenum (Mo), tantalum (Ta), and tungsten (W). The film thickness of the high-contrast film 5 should be less than or equal to the depth of the recesses 41 of the alignment uneven structure 4, sufficient contrast can be obtained, and sufficient light (UV) can be transmitted to the extent that the imprint resin filled in the recesses 41 of the alignment uneven structure 4 can be cured. For example, the film thickness of the high-contrast film 5 should be 1 nm or more, preferably 3 nm to 50 nm, and more preferably 5 nm to 50 nm. If the film thickness of the high-contrast film 10 is less than 1 nm, pinholes may be formed, or it may become difficult to recognize (detect) the high-contrast film 5 (alignment uneven structure 4) when aligning the imprint mold 1 and the transfer substrate 90. If it exceeds 50 nm, it may become difficult to cure the imprint resin filled in the recesses 41 of the alignment uneven structure 4. The "depth" of the recess 41 refers to the length from the top surface of the convex portion 42 adjacent to the recess 41 to the bottom surface of the recess 41 (length in the thickness direction of the substrate 2).

[0052] In the imprint mold 1 according to this embodiment, it is sufficient that a high-contrast film 5 is provided on the bottom surface of the recess 41, and the material constituting the high-contrast film 5 (high-contrast material) may be deposited on the bottom surface 431 of the recessed structure 43 or the top surface 421 of the convex portion 42, as long as alignment with the substrate 90 to be transferred is possible during the imprint process described later.

[0053] In this embodiment, the high-contrast film 5 may be provided continuously on the bottom surface and the side surface 41A of the recess 41 (see Figures 2B and 2C). In a cross-sectional view, the high-contrast film 5 provided on the bottom surface of the recess 41 is configured such that the film thickness T512 near the side surface 41A is thinner than the film thickness T511 at approximately the center of the in-plane direction of the bottom surface of the recess 41. During the imprint process using the imprint mold 1, the alignment uneven structure 4 of the imprint mold 1 and the alignment marks 93 of the transfer substrate 90 (see Figure 8A) are superimposed, and the imprint mold 1 and the transfer substrate 90 are optically aligned using the alignment mechanism of the imprint device. Optical alignment using the alignment mechanism of the imprint device is performed by detecting the alignment uneven structure 4 (high-contrast film 5) along the thickness direction of the imprint mold 1. If a high-contrast film 5 is not provided on the side surface 41A of the recess 41, the thinness of the film thickness at the periphery of the high-contrast film 5 will cause the periphery of the high-contrast film 5 to blur when the alignment uneven structure 4 is detected, making it difficult to detect the periphery of the high-contrast film 5. In the imprint mold 1 shown in Figure 2B, the high-contrast film 5 is provided continuously on the bottom surface and side surface 41A of the recess 41. As a result, the film thickness at the peripheral edge of the high-contrast film 5 in the thickness direction of the imprint mold 1 becomes equal to the length of the high-contrast film 5 provided on the side surface 41A (length in the thickness direction of the imprint mold 1), making it easy to detect the periphery of the high-contrast film 5. Note that the film thickness T52 of the high-contrast film 5 provided on the side surface 41A of the recess 41 is thinner than the film thickness T511 of the high-contrast film 5 provided on the bottom surface. Furthermore, as described later, when the corners 422 of the protrusion 42 have a rounded shape (see Figure 2B), the high-contrast film 5 provided on the side surface 41A of the recess 41 is configured to have a relatively thick film thickness near the bottom surface of the recess 41 and a relatively thin film thickness near the corners 422 of the protrusion 42, and the high-contrast film 5 does not need to be provided on the rounded corners 422.

[0054] In the imprint mold 1 according to this embodiment, the width W41 of the recess 41 of the alignment uneven structure 4 (see Figures 3 and 4) may be 0.8 μm or less, 0.1 μm to 0.8 μm, or 0.12 μm to 0.75 μm. When the depth of the alignment uneven structure 4 (the sum of the depth D43 of the recess structure 43 and the depth of the recess 41) is relatively deep (for example, about 200 nm to 300 nm), during the imprint process using the imprint mold 1, the imprint resin 94 on the transfer substrate 90 may not sufficiently fill the recess 41, and a thin layer of imprint resin 94 may adhere to the side surface 41A of the recess 41, for example (see Figure 2D). If the imprint resin 94 is cured in this state and the imprint mold 1 is pulled away, the thin layer of imprint resin 94 adhered to the side surface 41A may break, and defects may occur due to the broken pieces of imprint resin. To prevent such a situation from occurring, it is desirable to sufficiently fill the recesses 41 of the alignment uneven structure 4 with imprint resin 94. If the width W41 of the recesses 41 is 0.8 μm or less, the imprint resin 94 can be sufficiently filled into the recesses 41 by capillary force, thereby suppressing the occurrence of defects due to the fracture of the imprint resin 94.

[0055] Regarding the filling of the recess 41 with imprint resin 94 by capillary force, we will examine this using a circular pipe model in which the recess 41 having a width W 41 is considered as a circular pipe with radius r. In this circular pipe model, the capillary pressure P (Pa) is expressed by the following formula (1): P = 2γcosθ / r ... (1) In the above formula (1), r is the radius of the circular pipe (m), and γ is the surface free energy of the imprint resin 94 (J / m ２ ) or surface tension (N / m), and θ represents the contact angle (rad) of the imprint resin 94. As shown in formula (1), the capillary pressure P depends on the surface free energy γ and contact angle θ of the imprint resin 94, but for example, if the diameter of the circular tube (width W41 of the recess 41) is 0.8 μm, the surface free energy γ of the imprint resin 94 is 0.025 J / m ２As described above, if the contact angle θ is 35° or less, the pressure will be 1 atmosphere (101.325 kPa) or more, and it is presumed that a capillary force can be obtained that can contribute to filling the recesses 41 with the imprint resin 94. If the diameter of the circular tube (width W41 of the recesses 41) is smaller than 0.8 μm, the lower limit of the surface free energy γ of the imprint resin 94 can be further reduced, and the upper limit of the contact angle θ can be further increased, thereby increasing the capillary pressure P and making it easier to fill the recesses 41 with the imprint resin 94. Furthermore, if the imprint atmosphere during the imprint process using the imprint mold 1 (the gas that fills the space between the uneven pattern 3 formed on the pattern region PA of the first surface 21 of the substrate 2 of the imprint mold 1 and the imprint resin 94 when they are brought into contact, then the surface free energy of the surface of the recesses 41 of the alignment uneven structure 4 should be a predetermined value (for example, 0.020 J / m). ２ If the surface free energy of the surface of the recess 41 is less than or equal to a predetermined value (for example, 0.020 J / m), the contact angle θ of the imprint resin 94 with respect to the surface of the recess 41 becomes relatively larger, which relatively reduces the capillary pressure P in the above formula (1), making it difficult for the imprint resin 94 to fill the recess 41. ２ If the contact angle θ of the imprint resin 94 with respect to the surface of the recess 41 becomes relatively smaller, and the capillary pressure P in the above formula (1) becomes relatively larger, so that the imprint resin 94 can be sufficiently filled into the recess 41. The surface of the recess 41 may be subjected to a surface treatment to make its surface free energy greater than a predetermined value.

[0056] In order to manufacture an imprint mold 1 in which a high-contrast film 5 is provided at least on the bottom surface of the recess 41, it is necessary to deposit the high-contrast material constituting the high-contrast film 5 on the bottom surface of the recess 41. For this purpose, it is preferable that the width W41 of the recess 41 is 0.1 μm or more. If the width W41 of the recess 41 becomes relatively small, the uniformity of the high-contrast film 5 provided on the bottom surface of the recess 41 (uniformity of the film thickness, density, etc. of the high-contrast film 5) may deteriorate.

[0057] In the imprint mold 1 according to this embodiment, the corners 422 of the protrusions 42 of the alignment uneven structure 4 may have a rounded shape (see Figures 2B and 2C). When the imprint mold 1 is pulled away from the imprint resin 94 that has been filled into the recesses 41 of the alignment uneven structure 4 and hardened, if the corners 422 of the protrusions 42 do not have a rounded shape, stress tends to concentrate on the portion of the hardened imprint resin 94 to which the corners 422 of the protrusions 42 have been transferred, which may cause the imprint resin 94 to break. As in this embodiment, by having the corners 422 of the protrusions 42 have a rounded shape, when the imprint mold 1 is pulled away from the hardened imprint resin 94, the stress applied to the portion to which the corners 422 of the protrusions 42 have been transferred is dispersed, thereby suppressing the breakage of the imprint resin 94.

[0058] The radius of curvature R1 of the rounded corner portion 422 should be such that it can distribute the stress applied to the imprint resin 94 when the imprint mold 1 is pulled away from the hardened imprint resin 94. For example, it should be 7 nm or more, 12 nm or more, or approximately 12 nm to 25 nm. The imprint mold 1 according to this embodiment was manufactured by varying the depth D43 of the recessed structure 43 in the range of 20 nm to 100 nm, and the radius of curvature R1 of the corner 422 of the convex portion 42 and the depth D43 of the recessed structure 43 were determined. The radius of curvature R1 was 12.1 nm when the depth D43 of the recessed structure 43 was 20 nm, 15.0 nm when the depth D43 of the recessed structure 43 was 40 nm, 19.0 nm when the depth D43 of the recessed structure 43 was 70 nm, and 25.0 nm when the depth D43 of the recessed structure 43 was 100 nm. When the depth D43 of the recessed structure 43 was 0 nm, i.e., when there was no recessed structure 43, the radius of curvature R1 was 4.2 nm.

[0059] The corners 434 of the recessed structure 43 on the first surface 21 side of the substrate 2 may also have a rounded shape (see Figure 2B). In this case, the radius of curvature R2 of the corners 434 of the recessed structure 43 only needs to be smaller than the radius of curvature R1 of the corners 422 of the recess 42, for example, about 5 nm or less. Because the radius of curvature R2 of the corners 434 of the recessed structure 43 is smaller than the radius of curvature R1 of the corners 422 of the recess 42, the rounded shape of the corners 434 of the recessed structure 43 can be transferred with high precision to the imprint resin 90 on the substrate 90 by the imprint process using the imprint mold 1. Furthermore, because the radius of curvature R2 of the corners 434 of the recessed structure 43 is 5 nm or less, the transfer accuracy of the main transfer pattern 96 formed by the imprint process using the imprint mold 1 can be improved, and for example, the roughness of the main transfer pattern 96 can be reduced to ±2 nm or less. The transfer accuracy of the rounded corners 434 of the concave structure 43 is an important factor in the alignment accuracy when multiple imprint processes are performed on the substrate 90 to be transferred.

[0060] In this embodiment, the radii of curvature R1 and R2 may be values ​​calculated as follows. Note that, although an example of how to calculate the radius of curvature R1 is described below, the radius of curvature R2 can be calculated in the same manner. Furthermore, the calculation methods for the radii of curvature R1 and R2 are not limited to those described below.

[0061] First, image data of the cross-section of the imprint mold 1 is obtained. The image data of the cross-section only needs to include the corners 422 and 434 from which the radius of curvature is calculated.

[0062] Next, the image data of the cross-section is converted to 256-level image data, a predetermined threshold is set, and the 256-level image data is binarized into areas below the threshold and areas above the threshold. This results in a region A where the contrast is relatively light visually. Ｌ And, region A where the contrast is relatively darker. Ｄ Binarized image data can be obtained that is divided into two parts (see Figure 2E). In the example shown in Figure 2E, the recess 41 is in the thin region A. Ｌ Represented as such, the convex portion 42 is concentrated in region A. Ｄ It is represented as follows.

[0063] Next, from the binarized image data, a straight line (line segment Lu) is determined to be the top 421 of the convex portion 42, a straight line (line segment Ls) is determined to be the side surface 41A of the concave portion 41, and a curve (Lc) is determined to be the contour line of the corner 422 of the convex portion 42.

[0064] The area S of the region enclosed by the line segment obtained by extending the line segment (line segment Lu) identified as the top 421 of the convex portion 42, the line segment obtained by extending the line segment (line segment Ls) identified as the side surface 41A of the concave portion 41, and the curve (Lc) identified as the contour line of the corner 422 of the convex portion 42 is calculated. The area S can be calculated, for example, by measuring the number of pixels in the region enclosed by the line segments obtained by extending line segments Lu and Ls respectively and the curve Lc, and multiplying this number of pixels by the unit area of ​​one pixel. From the calculated area S, the radius of curvature R1 is calculated using the following formula (2).

[0065] In the above formula (2), S represents "the area of ​​the region enclosed by the line segments obtained by extending line segments Lu and Ls, respectively, and the curve Lc," and θ represents "the angle formed by line segments Lu and Ls."

[0066] In the imprint mold 1 according to the above embodiment, the recesses 41 and protrusions 42 of the alignment uneven structure 4 are formed on the bottom surface 431 of the recess structure 43, and the top 421 of the protrusion 42 is located on the second surface 22 side of the substrate 2 rather than the first surface 21. Therefore, it is possible to prevent the substrate 90 to be transferred from being processed by the resist pattern formed in correspondence with the alignment uneven structure 4 during the imprint process using the imprint mold 1.

[0067] [Method for Manufacturing Imprint Molds] A method for manufacturing an imprint mold according to this embodiment will now be described. The method for manufacturing the imprint mold 1 in this embodiment includes the steps of: preparing a mold substrate 20 having a first surface 201 and a second surface 202 located on the opposite side of the first surface 201; forming a relief pattern 3 in a pattern formation area (a region corresponding to the pattern area PA in the imprint mold 1) set on the first surface 201 of the mold substrate 20; and forming an alignment relief structure 4 in an alignment mark formation area (a region corresponding to the alignment area AA in the imprint mold 1) set on the first surface 201 of the mold substrate 20.

[0068] The mold substrate 20 can be a general substrate for imprint molding, such as a glass substrate such as a quartz glass substrate, soda glass substrate, fluorite substrate, calcium fluoride substrate, magnesium fluoride substrate, barium borosilicate glass, aluminoborosilicate glass, or other alkali-free glass substrate; a resin substrate such as a polycarbonate substrate, polypropylene substrate, polyethylene substrate, polymethyl methacrylate substrate, or polyethylene terephthalate substrate; a semiconductor substrate such as a silicon substrate or gallium nitride substrate; or a laminated substrate formed by laminating two or more substrates arbitrarily selected from these. It is preferable to use a transparent substrate. In this embodiment, "transparent" means that it is possible to transmit light of a wavelength that can cure the imprint resin, and that the transmittance of light rays with wavelengths of 160 nm to 400 nm is 60% or more, preferably 90% or more, and particularly preferably 95% or more.

[0069] The planar shape of the molding substrate 20 is not particularly limited, and examples include a roughly rectangular shape. When the molding substrate 20 is a quartz glass substrate commonly used for optical imprinting, the planar shape of the molding substrate 20 is usually roughly rectangular.

[0070] The size of the molding substrate 20 (size in plan view) is not particularly limited, but if the molding substrate 20 is the above-mentioned quartz glass substrate, for example, the size of the molding substrate 20 is approximately 152 mm x 152 mm. The thickness of the molding substrate 20 can be appropriately set in a range of approximately 300 μm to 10 mm, taking into consideration strength, handling suitability, etc.

[0071] Next, a first resist pattern 61 corresponding to the uneven pattern 3 is formed in the area where the pattern is to be formed on the first surface 201 of the mold substrate 20, and a second resist pattern 62 corresponding to the alignment uneven structure 4 is formed in the area where the alignment marks are to be formed on the first surface 201 of the mold substrate 20 (see Figure 5A).

[0072] The first resist pattern 61 and the second resist pattern 62 may be formed, for example, by imprint lithography, electron beam lithography using an electron beam lithography apparatus, or photolithography using a photomask having predetermined openings and light-shielding portions.

[0073] When forming the first resist pattern 61 and the second resist pattern 62 (see Figure 5A) by imprint lithography, a template set including multiple templates (see Figures 6A and 6B) can be used. For example, the template set may include a first template 81 and a second template 82. The first template 81 has a base portion 810 having a first surface 811 and a second surface 812 located opposite the first surface 811, and a first uneven structure 813 formed on the first surface 811 that corresponds to the uneven pattern 3, and a second uneven structure 814 that corresponds to the recesses 41 and protrusions 42 of the alignment uneven structure 4 (see Figure 6A). The second template 82 has a base portion 820 having a first surface 821 and a second surface 822 located opposite the first surface 821, and a protrusion structure 823 formed on the first surface 821 that corresponds to the recesses 43 of the alignment uneven structure 4 (see Figure 6B). The first template 81 is used to form the first resist pattern 61 and the second resist pattern 62. The second template 82 is used to form the resist pattern 71 (see Figure 5C), which will be described later.

[0074] An example of a method for forming a first resist pattern 61 and a second resist pattern 62 using a template set will be described. Imprint resin 80 is supplied to the first surface 201 of the mold substrate 20 (see Figure 7A). The method of supplying the imprint resin 80 is not particularly limited. For example, the imprint resin 80 may be supplied discretely to the first surface 201 of the mold substrate 20 by an inkjet method (see Figure 7A), or the imprint resin 80 may be supplied to the first surface 201 of the mold substrate 20 using a coating machine such as a spin coater or spray coater.

[0075] The first template 81 is brought close to the imprint resin 80 supplied to the first surface 201 of the mold substrate 20, and the imprint resin 80 is brought into contact with the first uneven structure 813 and the second uneven structure 814 of the first template 81, thereby filling the first uneven structure 813 and the second uneven structure 814 with the imprint resin 80 (see Figure 7B).

[0076] The imprint resin 80 filled in the first uneven structure 813 and the second uneven structure 814 is cured. The method for curing the imprint resin 80 can be appropriately selected according to the curing type of the imprint resin 80. For example, if the imprint resin 80 is a photocuring type, light (e.g., ultraviolet light) can be irradiated onto the imprint resin 80 via the first template 81 or the mold substrate 10. If the imprint resin 80 is a thermosetting type, heat can be applied to the imprint resin 80. If the imprint resin 80 is a thermoplastic type, the first template 81 can be brought into contact with the imprint resin 80 that has been heated and softened, and then the imprint resin 80 can be cured by letting it cool.

[0077] Subsequently, the first template 81 is separated from the cured imprint resin 80. In this way, the first resist pattern 61 for forming the uneven pattern 3 and the second resist pattern 62 for forming the recesses 41 and the protrusions 4 can be formed (see Figure 5A).

[0078] Using the first resist pattern 61 and the second resist pattern 62 formed on the first surface 201 of the molding substrate 20 as described above, the first surface 201 of the molding substrate 20 is etched. This allows the uneven pattern 3, as well as the recesses 41 and protrusions 42, to be formed on the first surface 201 of the molding substrate 20 simultaneously in a single etching process (see Figure 5B).

[0079] Next, imprint resin 80 is supplied to the first surface 201 on which the uneven pattern 3, and the recesses 41 and protrusions 42 are formed. The second template 82 is then brought close to the imprint resin 80 to bring it into contact with the protrusion structure 823 of the second template 82 (see Figure 7C). By curing the imprint resin 80 in this state, the protrusion structure 823 of the second template 82 is transferred to the imprint resin 80. Then, by separating the second template 82 from the imprint resin 80, a resist pattern 71 having a recessed pattern 72 for forming the recessed structure 43 of the alignment uneven structure 4 is formed (see Figure 5C). The recesses 41 and protrusions 42 formed on the first surface 201 of the molding substrate 20 are exposed through this recessed pattern 72. The constituent materials of the imprint resin 80 used to form the resist pattern 71, the method of supplying the imprint resin 80, and the curing method may be the same as those of the constituent materials of the imprint resin 80 used to form the first resist pattern 61 and the second resist pattern 62, and the method of supplying the imprint resin 80.

[0080] As described above, the resist pattern 71 formed on the first surface 201 of the molding substrate 20 is used as a mask to perform an etching process on the first surface 201 of the molding substrate 20 (see Figure 5D). The uneven pattern 3 formed on the first surface 201 of the molding substrate 20 is masked by the resist pattern 71 and is therefore not subjected to the etching process. On the other hand, the recesses 41 and protrusions 42 are exposed via the recess pattern 72, so etching causes the tops 421 of the protrusions 42 to be located on the second surface 202 side of the first surface 201 of the molding substrate 20. At the same time, a recessed structure 43 is formed on the first surface 201 of the molding substrate 20. As a result, the recesses 41 and protrusions 42 are formed on the bottom surface 431 of the recessed structure 43. This forms an alignment uneven structure 4 on the first surface 201 of the molding substrate 20.

[0081] When etching the first surface 201 of the molding substrate 20 using the resist pattern 71 as a mask (see Figure 5D), the etching process may be performed so that the corners 422 of the protrusions 42 have a rounded shape (rounded shape). In this etching process, for example, by applying isotropic dry etching, the corners 422 of the protrusions 42 can be rounded with a predetermined radius of curvature R1 (see Figures 2B and 2C). Specifically, in dry etching, the corners 422 of the protrusions 42 can be rounded with a predetermined radius of curvature R1 by changing the pressure conditions of the etching gas. The pressure conditions of the etching gas can be adjusted, for example, within a range of about 0.1 Pa to 10 Pa. It is also possible to round the corners 422 of the protrusions 42 with a predetermined radius of curvature R1 by performing dry etching under highly anisotropic, low-pressure conditions, followed by isotropic wet etching.

[0082] Finally, the high-contrast material constituting the high-contrast film 5 is deposited on the bottom surface of the recess 41, thereby forming the high-contrast film 5 on the bottom surface of the recess 41 exposed from the recess pattern 72 of the resist pattern 71 (see Figure 5E). A conventionally known film deposition method (for example, CVD, PVD, sputtering, etc.) can be used to form the high-contrast film 5. Then, the resist pattern 71 is removed from the first surface 201 of the mold substrate 20. This allows the imprint mold 1 according to this embodiment (see Figure 1) to be manufactured.

[0083] In the above description, the high-contrast film 5 is formed on the bottom surface of the recess 41 by depositing the high-contrast material constituting the high-contrast film 5 on the bottom surface of the recess 41 (see Figure 5E), but the invention is not limited to this embodiment.

[0084] For example, after an etching process to form the alignment uneven structure 4 (see Figure 5D), the resist pattern 71 is removed from the first surface 201 of the mold substrate 20, and a high-contrast material film 51 is formed to cover the first surface 201 of the mold substrate 20 (see Figure 5F). Next, a resist layer 73 is formed in the region where the high-contrast film 5 is to be formed, i.e., the resist layer 73 is thicker than the alignment uneven structure 4 (see Figure 5G). The resist layer 73 can be formed, for example, by an imprint process using a template having recesses at positions corresponding to the alignment uneven structure 4 on the mold substrate 20. Then, the resist layer 73 and the high-contrast material film 51 are removed by etching, leaving the high-contrast material film 51 continuous with the bottom surface and side surface 41A of the recess 41 of the alignment uneven structure 4 (see Figure 5H). This makes it possible to form a high-contrast film 5 continuous with the bottom surface and side surface 41A of the recess 41 of the alignment uneven structure 4.

[0085] As a result of the etching process described above (see Figure 5D), if the corners 422 of the protrusion 42 are rounded (rounded), after the resist layer 73 is removed by etching and the high-contrast material film 51 formed on the top 421 of the protrusion 42 is exposed (see Figure 5I), as etching progresses further, the upper end of the high-contrast material film 51 along the side surface 41A is etched while maintaining the shape of the high-contrast material film 51 before etching. Because the corners 422 have a rounded shape with a predetermined radius of curvature R1, and the portion of the high-contrast material film 51 formed along the corners 422 also has a rounded shape, the upper end of the high-contrast material film 51 along the side surface 41A will have a rounded shape (see Figure 5J). Therefore, when the etching of the high-contrast material film 51 on the top 421 of the protrusion 42 is completed and the top 421 is exposed, the film thickness at the upper end of the high-contrast material film 51, which is continuous from the bottom surface to the side surface 41A, is relatively thick near the bottom surface of the recess 41 and relatively thin near the corner 422 of the protrusion 42 (near the upper end). In this way, the imprint mold 1 (see Figure 1) according to this embodiment can be manufactured.

[0086] [Imprint Method] An imprint method using the imprint mold 1 according to this embodiment will be described. Prepare the imprint mold 1 and a transfer substrate 90 having a first surface 91 and a second surface 92 located on the opposite side of the first surface 91, with alignment marks 93 formed in the scribe area of ​​the first surface 91. Supply imprint resin 94 to the first surface 91 of the transfer substrate 90 (see Figure 8A). The method of supplying imprint resin 94 to the first surface 91 of the transfer substrate 90 is not particularly limited. For example, the imprint resin may be supplied discretely to the first surface 91 of the transfer substrate 90 by an inkjet method, or the imprint resin 94 may be applied to the first surface 91 of the transfer substrate 90 using a coating machine such as a spin coater or spray coater.

[0087] The imprint mold 1 is brought close to the imprint resin 94 supplied to the first surface 91 of the substrate 90 to be transferred, and the imprint resin 94 is brought into contact with the imprint mold 1. In this state, the imprint mold 1 and the shot area of ​​the substrate 90 are aligned using the alignment uneven structure 4 of the imprint mold 1 and the alignment marks 93 of the substrate 90 to form the molded resin layer 95 (see Figure 8B). The alignment of the imprint mold 1 and the shot area of ​​the substrate 90 can be performed by overlapping the alignment uneven structure 4 of the imprint mold 1 and the alignment marks 93 formed on the substrate 90 and optically detecting the alignment using the alignment mechanism of the imprint device (not shown). The molded resin layer 95 can be formed by filling the uneven pattern 3 and the alignment uneven structure 4 of the imprint mold 1 with the imprint resin 94.

[0088] The imprint mold 1 is brought into contact with the resin layer 95 to be molded, and light (for example, ultraviolet light) is irradiated onto the resin layer 95 through the imprint mold 1 to cure the resin layer 95. After that, the imprint mold 1 is pulled away from the cured resin layer 95 (see Figure 8C).

[0089] In this way, a main transfer pattern 96, on which the raised and recessed pattern 3 of the imprint mold 1 is transferred, can be formed on the shot area of ​​the first surface 91 of the substrate 90 to be transferred (see Figure 8C). At the same time, an alignment transfer pattern 97, on which the alignment raised and recessed structure 4 is transferred, is formed on the scribe area of ​​the first surface 91 of the substrate 90 to be transferred (see Figure 8C). The first surface 91 of the substrate 90 on which the main transfer pattern 96 and the alignment transfer pattern 97 are formed is then subjected to an etching process using the main transfer pattern 96 and the alignment transfer pattern 97 as etching masks. At this time, the portion of the first surface 91 of the substrate 90 that is exposed via the main transfer pattern 96 is etched, thereby transferring the main transfer pattern 96 to the first surface 91 of the substrate 90. On the other hand, the scribe area on the first surface 91 of the substrate 90 is protected by the alignment transfer pattern 97, and the alignment transfer pattern 97 remains until the etching process using the main transfer pattern 96 as a mask is completed (see Figure 9). Therefore, the scribed area on the first surface 91 of the substrate 90 to be transferred is protected from etching. Thus, by using the imprint mold 1 according to this embodiment in the imprint process, the main transfer pattern 96 can be transferred to the shot area on the first surface 91 of the substrate 90 with high precision, and the scribed area can be prevented from being processed unintentionally.

[0090] In the imprint mold 1 according to this embodiment, if the corners 422 of the convex portion 42 of the alignment uneven structure 4 have a rounded shape, the width W41 of the recess 41 of the alignment uneven structure 4 is 0.8 μm or less, so that the imprint resin 94 can be sufficiently filled into the recess 41 by capillary force, and the occurrence of defects due to the breakage of the rising imprint resin 94 can be suppressed. Furthermore, because the corners 422 of the convex portion 42 of the alignment uneven structure 4 have a rounded shape (see Figure 2B), when the imprint mold 1 is pulled away from the hardened imprint resin 94, the stress applied to the portion to which the corners 422 of the convex portion 42 have been transferred is dispersed, so that the breakage of the imprint resin 94 can be suppressed.

[0091] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0092] 1...Imprint mold 2...Substrate 21...First surface 22...Second surface 3...Recessed pattern 31...Concave pattern 32...Convex pattern 4...Recessed structure for alignment 41...Recess 42...Convex part 43...Recessed structure

Claims

1. An imprint mold used to transfer the uneven pattern to an imprint resin supplied onto a transfer substrate, comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the uneven pattern has a concave pattern and a convex pattern; the alignment uneven structure has a concave portion and a convex portion; when a first virtual plane including the tops of the convex portions and a second virtual plane including the tops of the convex patterns are defined, the first virtual plane is located on the second surface side of the second virtual plane than the second virtual plane; and the first virtual plane is located on the second surface side of the second virtual plane to the extent that the imprint resin can be filled into the alignment uneven structure during imprint processing using the imprint mold.

2. The imprint mold according to claim 1, wherein the first virtual plane and the second virtual plane are planes substantially parallel to the first surface, and the length between the first virtual plane and the second virtual plane along the thickness direction of the substrate is 10 nm to 100 nm.

3. The imprint mold according to claim 1 or 2, wherein a high-contrast film is provided on the bottom surface of the recess of the alignment uneven structure, the film being made of a material different from the material constituting the substrate and having optical properties different from those of the substrate.

4. The imprint mold according to claim 3, wherein the high-contrast film is continuously provided on the bottom and side surfaces of the recesses of the alignment uneven structure.

5. The imprint mold according to claim 4, wherein the thickness of the high-contrast film located near the bottom surface, among the high-contrast films provided along the side surface, is thicker than the thickness of the high-cottonlast film provided at the end of the side surface.

6. The imprint mold according to claim 3, wherein the thickness of the high-contrast film is less than or equal to the depth of the recess of the alignment uneven structure.

7. The imprint mold according to claim 6, wherein the film thickness of the high-contrast film is 1 nm to 50 nm.

8. The imprint mold according to claim 1 or 2, wherein the alignment uneven structure is provided adjacent to the uneven pattern.

9. The imprint mold according to claim 1 or 2, wherein the alignment uneven structure comprises a concave structure and the concave portion and the convex portion provided on the bottom surface of the concave structure.

10. The imprint mold according to claim 9, wherein, in a plan view from the first surface side of the substrate, the length between the recess closest to the outer edge of the recessed structure and the outer edge of the recessed structure is 1 μm or more.

11. The imprint mold according to claim 1 or 2, wherein the width of the recess in the alignment uneven structure is 0.8 μm or less.

12. The imprint mold according to claim 3, wherein the width of the recess in the alignment uneven structure is 0.1 μm or more.

13. The imprint mold according to claim 11, wherein, in a cross-sectional view along the thickness direction of the substrate, the radius of curvature of the corners of the protrusions of the alignment uneven structure is 7 nm to 25 nm.

14. A method for manufacturing an imprint mold used to transfer the uneven pattern onto an imprint resin supplied onto a transfer substrate, comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, the method comprising: forming the uneven pattern in a pattern region set on the first surface of the substrate; forming recesses and protrusions in an alignment region set on the first surface of the substrate; and forming the alignment uneven structure having the recesses and protrusions by positioning the tops of the protrusions formed in the alignment region on the second surface side of the first surface, wherein the alignment uneven structure is formed to a depth such that the imprint resin can be filled into the alignment uneven structure during an imprint process using the imprint mold.

15. The method for manufacturing an imprint mold according to claim 14, wherein, in the step of forming the alignment uneven structure, a resist pattern having a recessed pattern that exposes the recess and the protrusion formed in the alignment region is formed, and the first surface of the substrate is etched using the resist pattern as a mask to form the alignment uneven structure.

16. A method for manufacturing an imprint mold according to claim 14 or 15, comprising forming a first resist pattern corresponding to the uneven pattern in the pattern region, forming a second resist pattern corresponding to the recesses and protrusions in the alignment region, and etching the first surface of the substrate using the first resist pattern and the second resist pattern as a mask to form the uneven pattern, as well as the recesses and protrusions.

17. The method for manufacturing an imprint mold according to claim 15, wherein the resist pattern is formed by an imprint process using a template having a convex structure corresponding to the concave pattern of the resist pattern.

18. A method for manufacturing an imprint mold according to claim 16, wherein the first resist pattern and the second resist pattern are formed by an imprint process using a template having an uneven structure corresponding to the first resist pattern and an uneven structure corresponding to the second resist pattern.

19. A method for manufacturing an imprint mold according to claim 14 or 15, comprising the step of forming a high-contrast film on the bottom surface of the recess of the alignment uneven structure.

20. A template set used to manufacture an imprint mold used to transfer the uneven pattern onto an imprint resin supplied onto a transfer substrate, comprising: a substrate having a first surface and a second surface located opposite to the first surface; an uneven pattern formed in a pattern region on the first surface side of the substrate; and an alignment uneven structure formed in an alignment region on the first surface side of the substrate, wherein the alignment uneven structure of the imprint mold has a recessed structure provided on the first surface of the substrate and recesses and protrusions formed on the bottom surface of the recessed structure; the template set comprises a first template and a second template, the first template having a first uneven structure corresponding to the uneven pattern and a second uneven structure corresponding to the recesses and protrusions; and the second template having a protrusion structure corresponding to the recessed structure.

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