JP7124585B2 - Manufacturing method of replica mold - Google Patents

Description

The present disclosure relates to a replica mold manufacturing method.

Nanoimprint technology, known as microfabrication technology, uses an imprint mold in which a fine uneven pattern is formed on the surface of a base material, and the fine uneven pattern is transferred to the workpiece by transferring the fine uneven pattern to the same size. It is a pattern forming technology that transfers. In particular, with the further miniaturization of wiring patterns and the like in semiconductor devices, nanoimprint technology has attracted attention in the manufacturing processes thereof.

A mold having a fine concavo-convex pattern used in such nanoimprint technology can be manufactured, for example, by electron beam (EB) lithography. Although the mold manufactured in this way has high accuracy in the shape and dimensions of the fine uneven pattern, the manufacturing cost is high. In some cases, defects may occur in the transfer pattern formed on the printed resin, etc., or the fine uneven pattern of the mold may be damaged.

If the mold is replaced with a new mold when a defect in the transferred pattern or damage to the fine uneven pattern of the mold occurs in this way, the cost of the product manufactured through the nanoimprint process will increase. Therefore, when performing a nanoimprint process on an industrial scale, generally, a mold manufactured by electron beam (EB) lithography or the like as described above is used as a master mold, and a replica mold prepared by nanoimprint lithography using the master mold. etc. are used.

The replica mold is prepared by preparing a replica mold substrate having a base material and convex structures protruding from the surface of the base material, and transferring a fine concavo-convex pattern of the master mold onto the upper surface of the convex structure parts of the replica mold substrate. Manufactured by When transferring the fine concave-convex pattern of the master mold onto the upper surface of the convex structure of the replica mold substrate, it is important to align the replica mold substrate and the master mold with high accuracy. By performing these alignments with high accuracy, it is possible to improve the positional accuracy on the upper surface of the convex structure portion of the fine concavo-convex pattern.

In general, the alignment of the replica mold substrate and the master mold is performed using alignment marks provided on both. As an alignment mark for aligning both, conventionally, an alignment mark formed of a dielectric material having a refractive index different from that of the imprint mold (see Patent Document 1) cannot be filled with imprint resin. An alignment mark consisting of a concavo-convex structure with deep recesses (see Patent Document 2), an alignment mark made of a material different from that of the imprint mold and capable of being imaged by an imaging device (see Patent Document 3), and a non-transfer area of the mold. Alignment marks (see Patent Document 4), etc., are known which are formed of a structure lower than the height of a mesa structure having a transfer region as an upper surface.

JP 2011-97051 A JP 2011-29642 A JP 2008-100507 A JP 2012-134319 A

The imprint mold described in Patent Document 4 has a non-transfer area around the mesa structure 300 on the substrate, and an alignment mark 400 made of a convex structure is formed in the non-transfer area. In manufacturing this imprint mold, a master mold 200 provided with an alignment mark 250 and a replica mold substrate 100 having a mesa structure 300 and an alignment mark 400 formed in a non-transfer region are prepared. By observing both the alignment marks 400 and 250 from the back side of the master mold 200 using the imaging device 700 or the like, the alignment of the master mold 200 and the replica mold substrate 100 can be performed with high accuracy (Fig. 13).

In recent years, along with the miniaturization of patterns and multilayering of pattern layers in products manufactured using nanoimprint technology, the positional accuracy of the fine uneven pattern formed on the upper surface of the mesa structure 300 of the replica mold substrate 100 on the upper surface of the mesa structure 300 is required to be further improved. In order to further improve the positional accuracy of the fine concavo-convex pattern, alignment marks 250 of master mold 200 and alignment marks 400 of replica mold substrate 100 should be more aligned when master mold 200 and replica mold substrate 100 are aligned. It is desirable to observe in close proximity.

However, in the replica mold substrate 100 for manufacturing the imprint mold described in Patent Document 4, the alignment mark 400 lower than the mesa structure 300 is formed in the non-transfer region one step below the mesa structure 300. , it is physically difficult to reduce the distance between the master mold 200 and the alignment mark 250 .

In view of the above problems, the present disclosure provides a method of manufacturing a replica mold that enables highly accurate alignment between a master mold and a replica mold substrate and enables formation of an uneven pattern with extremely high positional accuracy. as one purpose.

In order to solve the above problems, as one embodiment of the present disclosure, there is provided a method for manufacturing a replica mold having a transferred pattern by transferring a concavo-convex pattern of a master mold to a replica mold substrate, the replica mold substrate comprising: comprises a transparent substrate having a first surface and a second surface opposite to the first surface; a convex structure projecting from the first surface of the transparent substrate; and projecting from the first surface of the transparent substrate. and an alignment structure portion positioned around the convex structure portion in plan view from the first surface side of the transparent base material, wherein the master mold includes a first surface and a second surface facing the first surface. a transparent substrate having a surface, and the concave-convex pattern formed on the first surface of the transparent substrate and its surroundings, and formed at a position facing the alignment structure portion of the replica mold substrate. an imprint resin supply step of supplying imprint resin onto the protruded structure portion of the replica mold substrate; and the alignment mark of the master mold and the alignment of the replica mold substrate. an alignment step of aligning the master mold and the replica mold substrate by bringing the structure portions close to each other; a transfer step of developing the imprint resin between the concave-convex pattern of the master mold and the convex structure portion of the replica mold substrate by bringing it into contact with the resin; A curing step of curing the imprint resin developed between the convex structures of the mold, a releasing step of separating the master mold from the cured imprint resin, and after the releasing step, the cured imprint a first etching step of forming the transfer pattern on the convex structure by etching the replica mold substrate using a resin as a mask; and after the first etching step, the alignment structure portion of the replica mold substrate. and a second etching step of etching the alignment structure such that the upper surface of the alignment structure is substantially flush with the first surface of the transparent substrate .

The protrusion height of the alignment structure portion in the replica mold substrate may be equal to or less than the protrusion height of the protrusion structure portion, and the difference between the protrusion height of the alignment structure portion and the protrusion height of the protrusion structure portion is The positions of the master mold and the replica mold substrate are below the depth of focus of an image pickup device, and in the alignment step, the image pickup device picks up images of the alignment structures and the alignment marks of the master mold facing each other. can be matched.

An alignment mark may be formed on the upper surface of the alignment structure so as to face the alignment mark of the master mold .

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a method of manufacturing a replica mold that enables highly accurate alignment between a master mold and a replica mold substrate and enables formation of an uneven pattern with extremely high positional accuracy.

FIG. 1 is a plan view showing a schematic configuration of a replica mold substrate according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, showing a schematic configuration of a replica mold substrate according to an embodiment of the present disclosure. FIG. 3 is a partially enlarged cut end view showing a schematic configuration of a convex structure portion and an alignment structure portion of a replica mold substrate according to an embodiment of the present disclosure. FIG. 4 is a cut end view showing a schematic configuration of a master mold in one embodiment of the present disclosure. FIGS. 5A to 5D are process flow diagrams showing respective steps of a method for manufacturing a replica mold according to an embodiment of the present disclosure, using cut end surfaces. FIGS. 6(A) to 6(D) are process flow diagrams showing respective steps of the method of manufacturing a replica mold according to an embodiment of the present disclosure, which are subsequent to FIG. 5, by cutting end surfaces. FIG. 7 is a cut end view showing a schematic configuration near the convex structure and the alignment structure of the replica mold in one embodiment of the present disclosure. FIGS. 8A to 8D are process flow diagrams showing respective steps of a method for manufacturing a replica mold substrate according to an embodiment of the present disclosure, using cut end surfaces. FIGS. 9(A) to 9(D) are process flow diagrams showing respective steps of a method for manufacturing a replica mold substrate according to an embodiment of the present disclosure, which are subsequent to FIG. . FIGS. 10A to 10C are process flow diagrams showing respective steps of a method for manufacturing a replica mold substrate according to another embodiment of the present disclosure by cutting end faces. FIGS. 11A to 11E are process flow diagrams showing respective steps of a method for manufacturing a replica mold substrate according to another embodiment of the present disclosure by cutting end faces. FIG. 12 is a cut end view showing a schematic configuration of a replica mold substrate and a master mold in another embodiment of the present disclosure. FIG. 13 is a cut end view schematically showing a conventional alignment method using substrates for a master mold and a replica mold.

Embodiments of the present disclosure will be described with reference to the drawings.
In the drawings, in order to facilitate understanding, the shape, scale, ratio of vertical and horizontal dimensions, etc. of each part may be changed from the real thing or exaggerated. In this specification and the like, a numerical range represented by "to" means a range including the numerical values described before and after "to" as lower and upper limits, respectively. In this specification and the like, terms such as "film", "sheet", and "plate" are not distinguished from each other based on the difference in designation. For example, "plate" is a concept that includes members that can be generally called "sheets" and "films."

In the replica mold manufacturing method according to the present embodiment, the replica mold 1 is manufactured by transferring the uneven pattern 22 of the master mold 20 to the replica mold substrate 10 . Therefore, in describing the replica mold manufacturing method, the configurations of the replica mold substrate 10 and the master mold 20 will be described.

[Substrate for replica mold]
FIG. 1 is a plan view showing a schematic configuration of a replica mold substrate in this embodiment, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 showing a schematic configuration of the replica mold substrate in this embodiment. , and FIG. 3 is a partially enlarged cut end view showing the schematic configuration of the convex structure and the alignment structure of the replica mold substrate in this embodiment.

As shown in FIGS. 1 and 2, the replica mold substrate 10 according to the present embodiment includes a replica transparent substrate 11 having a first surface 11A and a second surface 11B facing the first surface 11A; A convex structure 12 protruding from the first surface 11A of the transparent substrate 11, a plurality of (four in the illustrated example) alignment structures 13 protruding from the first surface 11A, and formed on the second surface 11B side. and a recessed portion 14 in which the

As the transparent base material 11 for replicas, substrates generally used for replica molds, such as quartz glass substrates, soda glass substrates, fluorite substrates, calcium fluoride substrates, magnesium fluoride substrates, barium borosilicate glass, amino Glass substrates such as non-alkali glass substrates such as borosilicate glass and aluminosilicate glass, resin substrates such as polycarbonate substrates, polypropylene substrates, polyethylene substrates, polymethyl methacrylate substrates, polyethylene terephthalate substrates, and 2 arbitrarily selected from these A transparent substrate such as a laminated substrate obtained by laminating the above substrates can be used. In this embodiment, the term “transparent” means that light having a wavelength capable of curing the imprint resin can be transmitted, and means that the transmittance of light having a wavelength of 150 nm to 400 nm is 60% or more. However, it is preferably 90% or more, particularly preferably 95% or more.

The planar view shape of the replica transparent substrate 11 is not particularly limited, and may be, for example, a substantially rectangular shape. When the replica transparent substrate 11 is made of a quartz glass substrate that is generally used for optical imprinting, the shape of the replica transparent substrate 11 in a plan view is generally rectangular.

The size of the replica transparent substrate 11 (the size in plan view) is also not particularly limited. The size is about 152 mm×152 mm. Further, the thickness of the replica transparent base material 11 can be appropriately set in the range of, for example, about 300 μm to 10 mm in consideration of strength, handling suitability, and the like.

The convex structure 12 protruding from the first surface 11A of the replica transparent substrate 11 is provided substantially in the center of the replica transparent substrate 11 in plan view. The shape of the convex structure portion 12 in plan view is substantially rectangular. The size of the protruding structure 12 is appropriately set according to the product to be manufactured through imprint processing using the replica mold substrate 10, and is set to approximately 30 mm×25 mm, for example.

Projection height T _{12 of convex structure 12} (length along the thickness direction of replica transparent base material 11 between first surface 11A of replica transparent base material 11 and upper surface part 12A of convex structure 12) is not particularly limited as long as the replica mold substrate 10 of the present embodiment and the replica mold 1 (see FIG. 6D) produced therefrom can achieve the purpose of providing the convex structure portion 12. For example, It can be set to about 10 μm to 100 μm.

A hard mask layer (not shown) may be formed on the upper surface portion 12A of the convex structure portion 12 . Materials constituting the hard mask layer include, for example, metals such as chromium, titanium, tantalum, silicon, and aluminum; chromium-based compounds such as chromium nitride, chromium oxide, and chromium oxynitride; Examples include tantalum, tantalum compounds such as tantalum boride oxynitride, titanium nitride, silicon nitride, silicon oxynitride, and the like, and one of these may be used alone, or two or more arbitrarily selected may be used in combination. can.

Alignment structures 13 protruding from the first surface 11A of the replica transparent substrate 11 are provided around the convex structures 12 . In the present embodiment, the alignment structures 13 are provided in the vicinity of each of the four corners of the first surface 11A of the transparent substrate 11 for replica, but are not limited to this aspect. The alignment structures 13 are provided, for example, in the vicinity of two diagonal corners of the first surface 11A of the transparent base material 11 for replica, as long as they can be aligned with the master mold 20. Alternatively, it may be provided in the vicinity of each of three arbitrarily selected corners of the first surface 11A. Further, the alignment structure portion 13 may be provided along each of the two opposing sides of the first surface 11A that is substantially rectangular in plan view. Since the alignment structures 13 are used for alignment with the master mold 20 , they need only be provided at positions facing the alignment marks 25 of the master mold 20 .

Protrusion height T _{13 of alignment structure 13} (length along the thickness direction of replica transparent substrate 11 between first surface 11A of replica transparent substrate 11 and upper surface 12A of convex structure 12) may be equal to or less than the protrusion height T ₁₂ of the protruding structure portion 12 . If the projection height T ₁₃ of the alignment structure portion 13 is higher than the projection height T ₁₂ of the convex structure portion 12, the master mold 20 may and the alignment structure 13 may come into contact with each other.

The difference ΔT between the protrusion height T ₁₂ of the convex structure portion 12 and the protrusion height T ₁₃ of the alignment structure portion 13 is the imaging element 40 (FIG. 5 (B)) or less. Alignment between the master mold 20 and the replica mold substrate 10 is performed by applying the master mold 20 to the imprint resin 30 (see FIG. 5A) supplied to the upper surface portion 12A of the convex structure portion 12 of the replica mold substrate 10. This is performed while the uneven pattern 22 is in contact with the master mold 20. If the difference ΔT between the protrusion height T 12 of the protrusion structure ₁₂ and the protrusion height T ₁₃ of the alignment structure 13 exceeds the depth of focus, the master mold 20 and the At the time of alignment with the replica mold substrate 10, the alignment marks 15 and 25 of both cannot be simultaneously recognized by the imaging device 40, and there is a possibility that the accuracy of alignment is lowered. For example, the difference ΔT may be about 0 μm to 5 μm, preferably about 0 μm to 1 μm.

A concave alignment mark 15 is provided on the upper surface portion 13A of the alignment structure portion 13 . The shape (planar view shape) of the alignment mark 15 may be appropriately set according to the shape of the alignment mark 25 of the master mold 20. Examples thereof include a substantially square shape, a substantially cross shape, a substantially square shape, and the like. be done.

The size of the alignment mark 15 may be such that the alignment mark 15 can be recognized by the imaging device 40 (see FIG. 5B) or the like. For example, if the alignment mark 15 has a substantially square shape in plan view, the length of one side thereof may be about 1 μm to 100 μm.

A recess 14 having a predetermined size is formed on the second surface 11B of the transparent substrate 11 for replica. Due to the formation of the recessed portion 14, during the imprinting process using the replica mold 1 (see FIG. 6D) produced from the replica mold substrate 1 according to the present embodiment, especially with the imprinting resin. At the time of contact or peeling of the replica mold 1, the replica transparent substrate 11, particularly the upper surface portion 12A of the convex structure portion 12, can be curved. As a result, when the imprint resin is brought into contact with the upper surface portion 12A of the convex structure portion 12, gas is sandwiched between the uneven pattern 2 formed on the upper surface portion 12A of the convex structure portion 12 and the imprint resin. In addition, the uneven pattern 2 is transferred to the imprint resin, and the replica mold 1 can be easily peeled off from the formed resist pattern.

It is preferable that the planar view shape of the recessed portion 14 is substantially circular. Due to the substantially circular shape, the projections of the replica mold 1 can be adjusted during the imprinting process, particularly when the upper surface portion 12A of the convex structure portion 12 is brought into contact with the imprinting resin or when the replica mold 1 is peeled off from the imprinting resin. The upper surface portion 12A of the structural portion 12 can be curved substantially uniformly within its plane.

The size of the recessed portion 14 in a plan view is such that the projected structure portion 12 is included in the projection area obtained by projecting the recessed portion 14 onto the first surface 11A side of the transparent base material 11 for replica. , is not particularly limited. If the projected area is too large to include the convex structure 12, the entire surface of the upper surface 12A of the convex structure 12 of the replica mold 1 may not be curved effectively.

[Master mold]
Next, the master mold in this embodiment will be described. FIG. 4 is a cut end view showing a schematic configuration of the master mold in this embodiment.

The master mold 20 in this embodiment includes a master transparent substrate 21 having a first surface 21A and a second surface 21B facing the first surface 21A, and a pattern area on the first surface 21A of the master transparent substrate 21. 211, and alignment marks 25 provided in a non-pattern area 212 surrounding the pattern area 211 on the first surface 21A of the transparent base material 21 for master. The master mold 20 forms a transfer pattern (concavo-convex pattern) 2 obtained by transferring the concavo-convex pattern 22 on the upper surface portion 12A of the convex structure portion 12 of the replica mold substrate 10 described above, and the replica mold 1 (see FIG. 6D )) is used for manufacturing.

As the master transparent substrate 21, substrates commonly used for imprint molds, such as quartz glass substrates, soda glass substrates, fluorite substrates, calcium fluoride substrates, magnesium fluoride substrates, barium borosilicate glass, amino Glass substrates such as non-alkali glass substrates such as borosilicate glass and aluminosilicate glass, resin substrates such as polycarbonate substrates, polypropylene substrates, polyethylene substrates, polymethyl methacrylate substrates, polyethylene terephthalate substrates, and 2 arbitrarily selected from these A transparent substrate such as a laminated substrate formed by laminating the above substrates may be used.

The planar view shape of the master transparent base material 21 is not particularly limited, and may be, for example, a substantially rectangular shape. When the master transparent base material 21 is made of a quartz glass substrate that is generally used for optical imprinting, the shape of the master transparent base material 21 is generally rectangular in plan view.

The size of the master transparent base material 21 (the size in plan view) is not particularly limited either. The size is about 152 mm×152 mm. Further, the thickness of the master transparent base material 21 can be appropriately set in the range of, for example, about 300 μm to 10 mm in consideration of strength, handling suitability, and the like.

The shape, dimensions, etc. of the concave-convex pattern 22 correspond to the shape, dimensions, etc. required for the replica mold 1 (product manufactured using the replica mold 1) manufactured from the replica mold substrate 10 in this embodiment. can be set as appropriate. For example, the shape of the concave-convex pattern 22 includes a line-and-space shape, a pillar shape, a hole shape, a lattice shape, and the like. Also, the dimension of the uneven pattern 22 can be set to, for example, about 10 nm to 200 nm.

The alignment mark 25 is configured by a concave structure formed within the non-patterned area 212 on the first surface 21A. The alignment marks 25 are provided at positions facing the alignment structures 13 of the replica mold substrate 10 .

The shape of the concave structure forming the alignment mark 25 in plan view can be appropriately set so as to correspond to the shape of the alignment mark 15 of the replica mold substrate 10 . When the planar view shape of the alignment mark 15 is a substantially square shape or a substantially cross shape, for example, the planar view shape of the concave structure that constitutes the alignment mark 25 is the substantially square or substantially cross shape alignment mark 15 physically. Any shape that can be included is sufficient. Further, when the planar view shape of the alignment mark 15 is substantially square-shaped, for example, the planar-view shape of the concave structure forming the alignment mark 25 is physically included in the substantially square-shaped alignment mark 15 . It may be substantially cross-shaped, substantially square-shaped, or the like.

A recess 24 having a predetermined size is formed on the second surface 21B of the transparent base material 21 for master. By forming the recessed portion 24, when the replica mold 1 (see FIG. 6(D)) is produced by imprinting the replica mold substrate 10 using the master mold 20, especially with the imprint resin. At the time of contact or peeling of the master mold 20, the transparent master substrate 21, particularly the pattern region 211 provided with the uneven pattern 22, can be curved. As a result, when the uneven pattern 22 and the imprint resin are brought into contact with each other, it is possible to prevent gas from being trapped between the uneven pattern 22 and the imprint resin. The master mold 20 can be easily peeled off from the resist pattern to which the pattern 22 is transferred.

It is preferable that the planar view shape of the recessed portion 24 is substantially circular. The substantially circular shape allows the pattern region 211 of the master mold 20 to be aligned with the pattern region 211 during the imprinting process, particularly when the uneven pattern 22 and the imprinting resin are brought into contact with each other or when the master mold 20 is peeled off from the imprinting resin. It can be curved substantially uniformly in the plane.

The size of the recessed portion 24 in a plan view is large enough to include the pattern region 211 (concavo-convex pattern 22) in the projected region of the recessed portion 24 projected onto the first surface 21A side of the transparent master substrate 21. It is not particularly limited as long as it is low. If the projection area has a size that cannot include the pattern area 211 (the uneven pattern 22), the entire surface of the pattern area 211 of the master mold 20 may not be effectively curved.

[Manufacturing method of replica mold]
Next, a method of manufacturing a replica mold according to the present embodiment using the master mold 20 and the replica mold substrate 10 having the above-described configurations will be described. 5 and 6 are process flow diagrams showing respective steps of the replica mold manufacturing method according to the present embodiment by cutting end faces.

First, the master mold 20 having the above configuration and the replica mold substrate 10 having the hard mask layer 16 formed on the upper surface portion 12A of the convex structure portion 12 are prepared. The imprint resin 30 is supplied to the portion 12A (see FIG. 5A).

The imprint resin 30 (resist material) is not particularly limited, and resin materials generally used for imprint processing (eg, ultraviolet curable resin, thermosetting resin, etc.) can be used. The imprint resin 30 includes a release agent for easily separating the master mold 20, and adhesion for improving adhesion to the upper surface portion 12A (hard mask layer 16) of the convex structure portion 12 of the replica mold substrate 10. A drug or the like may be included.

The amount of the imprint resin 30 supplied to the upper surface portion 12</b>A of the convex structure portion 12 may be an amount that can completely fill the uneven pattern 22 of the master mold 20 with the imprint resin 30 .

Next, the uneven pattern 22 formed on the first surface 21A of the master mold 20 is brought into contact with the imprint resin 30 supplied to the upper surface portion 12A of the convex structure portion 12, thereby The imprint resin 30 is spread between the convex structure portion 12 of the replica mold substrate 10 and the upper surface portion 12A, and the uneven pattern 22 is filled with the imprint resin 30 (see FIG. 5B). By observing the alignment marks 25 of the master mold 20 and the alignment marks 15 of the replica mold substrate 10 in this state (the state in which the imprint resin 30 is not yet cured), the master mold 20 and the replica mold can be identified by observing the alignment marks 25 of the master mold 20 and the alignment marks 15 of the replica mold substrate 10 with the imaging device 40 or the like. Alignment with the substrate 10 is performed.

In the present embodiment, the alignment mark 15 formed on the upper surface portion 13A of the alignment structure portion 13 and the alignment mark 25 of the master mold 20 can be observed with the imaging device 40 or the like in a state of being extremely close to each other. The alignment mark 15 and the alignment mark 25 can be easily recognized, and their alignment can be performed with high accuracy.

After the alignment of both is completed, the imprint resin 30 is irradiated with light to be cured, and then the master mold 20 is released. As a result, a resist pattern 31 is formed by transferring the uneven pattern 22 to the upper surface portion 12A of the convex structure portion 12 of the replica mold substrate 10 (see FIG. 5C).

Subsequently, the remaining film of the resist pattern 31 is removed (see FIG. 5D), and using the resist pattern 31 as a mask, a replica is formed by a dry etching process using, for example, a chlorine-based (Cl ₂ +O ₂ ) etching gas. A hard mask pattern 17 is formed by etching the hard mask layer 16 formed on the upper surface portion 12A of the convex structure portion 12 of the mold substrate 10 (see FIG. 6A).

Then, using the hard mask pattern 17 as a mask, the replica mold substrate 10 is subjected to a dry etching process to form an uneven pattern 2 on the upper surface portion 12A of the convex structure portion 12 (see FIG. 6B).

Thereafter, the hard mask pattern 17 remaining on the upper surface portion 12A of the convex structure portion 12 is removed, and a resist pattern 51 is formed to cover the first surface 11A of the replica transparent base material 11 so as to expose the alignment structure portion 13. (See FIG. 6(C)). The resist pattern 51 is formed by forming a resist layer covering the first surface 11A of the replica transparent base material 11, and then exposing and developing the resist layer so as to expose only the alignment structure portion 13. obtain. Then, using the resist pattern 51 as a mask, the first surface 11A of the replica transparent substrate 11 is dry-etched or wet-etched to remove the alignment structures 13, thereby manufacturing the replica mold 1 (FIG. 6(D)). Dry etching treatment for replica transparent substrate 11 (dry etching treatment for forming uneven pattern 2 (see FIG. 6B)) and dry etching treatment for removing alignment structure 13 (see FIG. 6D) )) can be performed by appropriately selecting an etching gas according to the type of the constituent material of the replica transparent substrate 11 . As an etching gas, for example, a fluorine-based gas or the like can be used. Further, hydrofluoric acid or the like may be used as an etchant in the wet etching process for the replica transparent substrate 11 (wet etching process for removing the alignment structure 13 (see FIG. 6D)).

The removal of the alignment structure 13 may be performed until the first surface 11A of the transparent substrate 11 for replica becomes substantially flush, but at least the protrusion height T13 of the alignment structure ₁₃ is reduced to the level before the dry etching process. Alternatively, the alignment structure 13 may be etched so as to be lower than before the wet etching process. Preferably, the protrusion height T ₁₃ of the alignment structure 13 is continuously imprinted (by step-and-repeat) on a plurality of transfer regions on a substrate to be transferred such as a silicon wafer using the replica mold 1. , the concave-convex pattern 2 has already been transferred to one transfer region on the substrate to be transferred and a resist pattern is formed thereon, and imprint processing is performed on a transfer region adjacent to the transfer region. The alignment structure 13 is etched and removed so that the alignment structure 13 does not interfere with (contact with) the resist pattern. More preferably, when the replica mold 1 is viewed from the side, the upper surface portion 13A of the alignment structure portion 13 is located first relative to the line segment L connecting the outer edge portion of the convex structure portion 12 and the outer edge portion of the first surface 11A of the replica mold 1. The alignment structure 13 is etched and removed so as to be positioned on the surface 11A side (see FIG. 7). In this case, the difference ΔT between the protrusion height T 12 of the protrusion structure ₁₂ and the protrusion height T ₁₃ of the alignment structure 13 becomes smaller as the alignment structure 13 is brought closer to the protrusion structure 12 . On the other hand, if the alignment structure portion 13 and the convex structure portion 12 are in complete contact with each other, or if the alignment structure portion 13 and the convex structure portion 12 are too close to each other, the unevenness of the master mold 20 is caused by the imprint resin 30 . When the pattern 22 is brought into contact (see FIG. 5B) and the imprint resin 30 overflows from the upper surface portion 12A of the convex structure portion 12, the imprint resin 30 flows into the alignment mark 15. Sometimes. As a result, the alignment marks 15 and 25 are recognized by the imaging element 40 (see FIG. 5B) by matching the refractive indices of the master transparent base material 21, the replica transparent base material 11, and the imprint resin 30. may become difficult. Therefore, it is preferable that the convex structure 12 and the alignment structure 13 are spaced apart by 10 μm or more.

For example, the replica mold substrate 10 uses a quartz glass substrate having a size of 152 mm×152 mm as the replica transparent base material 11, and has a convex structure portion 12 having a size of about 30 mm×25 mm and a protrusion height T ₁₂ of 30 μm. It is assumed that it is positioned at the center of the first surface 11A of the replica transparent substrate 11 . Also, the depth of the uneven pattern 22 of the master mold 20 is assumed to be 60 nm. When the alignment structure 13 having a size of about 40 μm×40 μm in plan view is positioned at a distance of 60 μm from each side of the convex structure 12, the protrusion height T ₁₂ of the protrusion structure 12 and the protrusion height of the alignment structure 13 are The difference ΔT from the height T ₁₃ should be 110 nm or more. When the alignment structure 13 is positioned at a distance of 200 μm from each side of the convex structure 12, the difference ΔT should be 180 nm or more.

That is, the protrusion height T ₁₂ of the convex structure 12, the distance D1 between the outer edge of the convex structure 12 and the outer edge of the first surface 11A of the replica transparent substrate 11, the outer edge of the alignment structure 13 and the replica In relation to the distance D2 from the outer edge of the first surface 11A of the transparent base material 11 and the depth D3 of the uneven pattern 22 of the master mold 20, the difference ΔT is preferably within the range shown by the following formula.
ΔT≧T ₁₂ (1−(D2/D1))+D3

In the method of manufacturing a replica mold according to the present embodiment, the alignment marks 15 of the replica mold substrate 10 and the alignment marks 25 of the master mold 20 can be aligned in a state of being extremely close to each other. Positioning can be performed with high precision, and as a result, the uneven pattern 2 can be formed with extremely high positional precision.

[Manufacturing method of substrate for replica mold]
A method for manufacturing the replica mold substrate described above will be described. 8 and 9 are process flow charts showing respective steps of the method for manufacturing a replica mold substrate according to the present embodiment by cutting end faces.

First, it has a first surface 11A′ and a second surface 11B′ facing the first surface 11A′, and a hard mask layer 50′ is formed on the first surface 11A′, and the second surface 11B′ side A transparent substrate 11' having recesses 14' formed therein is prepared, and a resist pattern 60' having openings corresponding to the alignment marks 15 is formed on the hard mask layer 50' (see FIG. 8A). ).

As the transparent substrate 11', a substrate commonly used as a replica mold substrate, such as a quartz glass substrate, a soda glass substrate, a fluorite substrate, a calcium fluoride substrate, a magnesium fluoride substrate, barium borosilicate glass, and aminoborosilicate. Glass substrates such as non-alkali glass substrates such as glass and aluminosilicate glass substrates, resin substrates such as polycarbonate substrates, polypropylene substrates, polyethylene substrates, polymethyl methacrylate substrates, polyethylene terephthalate substrates, and two or more arbitrarily selected from among these substrates A transparent substrate such as a laminated substrate formed by laminating substrates can be used.

The shape of the transparent base material 11 ′ in plan view is not particularly limited, and may be, for example, a substantially rectangular shape. When the transparent base material 11' is made of a quartz glass substrate generally used for optical imprinting, the shape of the transparent base material 11' in plan view is generally rectangular.

The size of the transparent base material 11' (the size in plan view) is not particularly limited, either. It is about 152 mm x 152 mm. In addition, the thickness of the transparent base material 11' can be appropriately set, for example, in the range of about 300 μm to 10 mm in consideration of strength, handling suitability, and the like.

Materials constituting the hard mask layer 50′ include, for example, metals such as chromium, titanium, tantalum, silicon, and aluminum; chromium-based compounds such as chromium nitride, chromium oxide, and chromium oxynitride; Tantalum compounds such as tantalum boride and tantalum boride oxynitride, titanium nitride, silicon nitride, silicon oxynitride, etc., may be mentioned, and one of these may be used alone or two or more arbitrarily selected may be used in combination. be able to.

The hard mask layer 50' constitutes a hard mask pattern 51' for forming the alignment mark 15, the convex structure 12, and the alignment structure 13 in the process described later. Therefore, the thickness of the hard mask layer 50' depends on the etching selectivity according to the material forming the transparent base material 11', the depth of the alignment marks 15 on the replica mold substrate 10, and the protrusion height of the convex structure 12. It is appropriately set in consideration of _T12 and the like. For example, the thickness of the hard mask layer 50' can be appropriately set within a range of approximately 10 nm to 100 nm.

The method of forming the hard mask layer 50' on the first surface 11A' of the transparent substrate 11' is not particularly limited, and examples thereof include sputtering, PVD (Physical Vapor Deposition), CVD (Chemical Vapor Deposition), and the like. and a known film forming method.

The resist pattern 60' is formed by forming a resist layer by spin coating or the like so as to cover the hard mask layer 50' on the first surface 11A' of the transparent substrate 11', and applying a photoresist having a predetermined opening in the resist layer. It can be formed by performing exposure processing and development processing through a mask (not shown).

The material constituting the resist layer is not particularly limited, and for example, a negative-type or positive-type photosensitive material can be used, but it is preferable to use a positive-type photosensitive material. The thickness of the resist layer is not particularly limited, and can be appropriately set in consideration of the selection ratio according to the constituent material of the hard mask layer 50', the thickness of the hard mask layer 50', and the like.

Next, using the resist pattern 60′ as an etching mask, the hard mask layer 50′ exposed from the opening is dry-etched using, for example, a chlorine-based (Cl ₂ +O ₂ ) etching gas, and the remaining resist pattern 60′ is etched. to remove As a result, a hard mask pattern 51' having openings corresponding to the alignment marks 15 is formed (see FIG. 8B).

Subsequently, using the hard mask pattern 51' as an etching mask, the transparent substrate 11' exposed from the opening of the hard mask pattern 51' is dry-etched to form the alignment mark 15 (see FIG. 8C). The dry etching treatment of the transparent base material 11' can be performed by appropriately selecting an etching gas according to the type of material constituting the transparent base material 11'. As an etching gas, for example, a fluorine-based gas or the like can be used.

Next, a resist pattern 61' corresponding to the convex structure portion 12 and the alignment structure portion 13 is formed on the hard mask pattern 51' (see FIG. 8D). The resist pattern 61' is formed by forming a resist layer by spin coating or the like so as to cover the hard mask pattern 51' on the first surface 11A' of the transparent base material 11' and the alignment marks 15, and applying a predetermined amount to the resist layer. It can be formed by performing exposure processing and development processing through a photomask (not shown) having openings. The material constituting the resist layer is not particularly limited, and for example, a negative-type or positive-type photosensitive material can be used, but it is preferable to use a positive-type photosensitive material. The thickness of the resist layer is not particularly limited, and can be appropriately set in consideration of the selection ratio according to the constituent material of the hard mask pattern 51', the thickness of the hard mask pattern 51', and the like.

Using the resist pattern 61′ as an etching mask, the hard mask pattern 51′ exposed from the opening of the resist pattern 61′ is dry-etched using, for example, a chlorine-based (Cl ₂ +O ₂ ) etching gas to form a hard mask pattern. 52' is formed (see FIG. 9(A)).

Subsequently, using the hard mask pattern 52' as an etching mask, the transparent substrate 11' exposed from the opening of the hard mask pattern 52' is dry-etched or wet-etched to form the convex structure 12 and the alignment structure 13. (See FIG. 9B). The dry etching treatment of the transparent base material 11' can be performed by appropriately selecting an etching gas according to the type of material constituting the transparent base material 11'. As an etching gas, for example, a fluorine-based gas or the like can be used. In addition, the wet etching treatment of the transparent base material 11' can be performed by appropriately selecting an etchant according to the type of the constituent material of the transparent base material 11'. As an etchant, for example, hydrofluoric acid or the like can be used.

Since the alignment structure 13 formed as described above has substantially the same protrusion height as the protrusion structure 12, the protrusion height of the alignment structure 13 is lower than the protrusion height of the protrusion structure 12. There is a need to. Therefore, after removing the hard mask pattern 52', a resist pattern 62' is formed so as to expose only the alignment structure 13 (see FIG. 9C), and the resist pattern 62' is used as an etching mask. The alignment structure 13 exposed from the opening of the pattern 62' is dry etched. As a result, the protrusion height of the alignment structure portion 13 can be reduced (see FIG. 9D), and the replica mold substrate 10 according to this embodiment is manufactured.

In the manufacturing method described above, the alignment structures 13 are formed after the alignment marks 15 are formed. They may be formed in the same process. FIG. 10 is a process flow diagram showing each process of a method for manufacturing a replica mold substrate according to another embodiment of the present disclosure by cutting end faces. Components similar to those shown in FIGS. 8 and 9 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, a resist pattern 63' corresponding to the convex structure portion 12, the alignment structure portion 13 and the alignment mark 15 is formed on the hard mask layer 50' (see FIG. 10A). Next, using the resist pattern 63′ as an etching mask, the hard mask layer 50′ exposed from the opening of the resist pattern 63′ is dry-etched using, for example, a chlorine-based (Cl ₂ +O ₂ ) etching gas. A hard mask pattern 53' is formed (see FIG. 10B).

Subsequently, using the hard mask pattern 53′ as an etching mask, the transparent substrate 11′ exposed from the opening of the hard mask pattern 53′ is dry-etched or wet-etched, thereby removing the convex structure 12, the alignment structure 13, and the alignment structures. A mark 15 is formed (see FIG. 10(C)).

Since the alignment structure 13 formed as described above has substantially the same protrusion height as the protrusion 12 , the protrusion height T ₁₃ of the alignment structure 13 is equal to the protrusion height of the protrusion 12 . It is preferably lower than _T12 . For this purpose, after removing the hard mask pattern 53', a resist pattern 62' is formed so as to expose only the alignment structure 13 (see FIG. 9C), and the resist pattern 62' is used as an etching mask. The alignment structure 13 exposed from the opening of the resist pattern 62' is dry-etched. As a result, the protrusion height T13 of the alignment structure ₁₃ can be reduced (see FIG. 9D), and the replica mold substrate 10 according to this embodiment is manufactured.

Further, when the convex structure 12 is formed by wet etching, the alignment structure 13 and the alignment mark 15 having a protrusion height _T13 lower than that of the convex structure 12 are formed at the same time as the convex structure 12 is formed. good too. FIG. 11 is a process flow diagram showing each process of a method for manufacturing a replica mold substrate according to another embodiment of the present disclosure by cutting end faces. Components similar to those shown in FIGS. 8 to 10 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, a resist pattern 631' corresponding to the convex structure 12 and a resist pattern 632' corresponding to the alignment structure 13 and the alignment marks 15 are formed on the hard mask layer 50' (see FIG. 11A). Next, using the resist patterns 631′ and 632′ as etching masks, the hard mask layer 50′ exposed from the openings of the resist patterns 631′ and 632′ is etched using, for example, chlorine-based (Cl ₂ +O ₂ ) etching gas. Then, a hard mask pattern 531' corresponding to the convex structure 12 and a hard mask pattern 532' corresponding to the alignment structure 13 and the alignment mark 15 are formed (see FIG. 11B).

As will be described later, the convex structures 12, the alignment structures 13 and the alignment marks 15 are formed by wet etching using the hard mask patterns 531′ and 532′ as masks. The hard mask pattern 532' is peeled off during the wet etching process. Thereby, the protrusion height of the alignment structure portion 13 can be reduced. Therefore, the dimensions of the hard mask pattern 532' and the resist pattern 632' for forming the hard mask pattern 532' can be appropriately set to such an extent that the hard mask pattern 532' is peeled off during the wet etching process.

Subsequently, using the hard mask patterns 531' and 532' as etching masks, the transparent substrate 11' exposed from the openings of the hard mask patterns 531' and 532' is wet-etched.

At the beginning of the wet etching process, etching progresses downward (in the thickness direction of the transparent base material 11′) from the outer edges of the hard mask patterns 531′ and 532′ (see FIG. 11C), and gradually the transparent base material is etched. Etching progresses in the in-plane direction of 11' (see FIG. 11(D)). That is, etching progresses isotropically. After the hard mask pattern 532' is peeled off, the wet etching process is continued on the transparent substrate 11' using the hard mask pattern 531' as a mask. Since the hard mask pattern 532′ is peeled off during the wet etching process, the protrusion height T ₁₃ of the alignment structure 13 is lower than the protrusion height T ₁₂ of the convex structure 12. (See FIG. 11(E)). Thus, the replica mold substrate 10 according to this embodiment is manufactured.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

In the above-described embodiment, the replica mold substrate 10 includes the alignment structure portion 13 having a lower projection height than the protruding structure portion 12, but the present invention is not limited to this aspect. do not have. For example, as shown in FIG. 12, the master mold 20 may include an alignment structure 23 protruding from the first surface 21A of the transparent base material 21 for master. In this case, the projection height T ₂₃ of the alignment structure 23 may be lower than the projection height T ₁₂ of the convex structure 12 of the replica mold substrate 10 .

DESCRIPTION OF SYMBOLS 10... Substrate for replica mold 11... Transparent base material for replica 11A... 1st surface 11B... 2nd surface 12... Convex structure part 13... Alignment structure part 15... Alignment mark 16... Hard mask layer 1... Replica mold 2... Uneven pattern 20... Master mold 21... Transparent substrate for master 22... Concavo-convex pattern 25... Alignment mark

Claims (4)

A method for manufacturing a replica mold having a transferred pattern by transferring a pattern of protrusions and recesses of a master mold to a substrate for a replica mold, the method comprising:
The replica mold substrate comprises: a transparent substrate having a first surface and a second surface facing the first surface; a projecting structure projecting from the first surface of the transparent substrate; an alignment structure projecting from the first surface and positioned around the convex structure in a plan view from the first surface of the transparent substrate;
The master mold comprises a transparent substrate having a first surface and a second surface facing the first surface, and the uneven pattern formed on the first surface of the transparent substrate and its surroundings, an alignment mark formed at a position facing the alignment structure portion of the replica mold substrate,
an imprint resin supplying step of supplying an imprint resin onto the protruded structure portion of the replica mold substrate;
an alignment step of aligning the master mold and the replica mold substrate by bringing the alignment marks of the master mold and the alignment structures of the replica mold substrate close to each other;
By bringing the concavo-convex pattern of the master mold into contact with the imprint resin supplied onto the protruding structure of the replica mold substrate, the concavo-convex pattern of the master mold and the protruding structure of the replica mold substrate are aligned. a transfer step of developing the imprint resin in between;
a curing step of curing the imprint resin developed between the uneven pattern of the master mold and the convex structure portion of the replica mold substrate;
a releasing step of separating the master mold from the cured imprint resin;
a first etching step of forming the transfer pattern on the convex structure by etching the replica mold substrate using the cured imprint resin as a mask after the mold release step ;
After the first etching step, a second etching is performed to etch the alignment structure so that the top surface of the alignment structure of the replica mold substrate is substantially flush with the first surface of the transparent base material. A method for manufacturing a replica mold, comprising the steps of: 2. The method of manufacturing a replica mold according to claim 1, wherein the protrusion height of the alignment structure in the replica mold substrate is equal to or less than the protrusion height of the convex structure. a difference between the protrusion height of the alignment structure and the protrusion height of the convex structure is less than or equal to the depth of focus of the imaging element;
3. The replica according to claim 2, wherein in the alignment step, the master mold and the replica mold substrate are aligned while imaging the alignment structures and the alignment marks of the master mold facing each other with the imaging device. Mold manufacturing method. 4. The method of manufacturing a replica mold according to claim 1, wherein an alignment mark is formed on the upper surface of the alignment structure so as to face the alignment mark of the master mold.

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