JP2016149578A - Production method of replica template for nanoimprinting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a replica template, by which mold releasing is easy, generation of defects is reduced, and damages on a template are substantially prevented, in the production method of the replica template by a nanoimprinting method using a master template.SOLUTION: A transfer-target substrate has a protruding step structure on a light-transmitting substrate, where a pattern region in a first major surface for forming a transfer pattern is higher than a peripheral region, and has a recess on a second major surface opposing to the first major surface. In a step of forming a photo-curable resin layer on the first major surface of the transfer-target substrate, the first major surface side of the transfer-target substrate is disposed as a top side while the second major surface side of the transfer-target substrate is disposed as a bottom side; a field edge is defined; a photo-curable resin layer is formed on the protruding step structure of the transfer-target substrate; and the transfer pattern is formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a template used in a nanoimprint method for forming a fine concavo-convex pattern, and more particularly to a method for manufacturing a replica template manufactured by a nanoimprint method using a master template.

  In recent years, particularly in semiconductor devices, high speed operation and low power consumption operation are required due to further progress in miniaturization, and high technology such as integration of functions called system LSIs is required. Under such circumstances, the lithography technology, which is essential for producing semiconductor device patterns, has pointed out the limitations of the photolithographic method due to the problem of exposure wavelength as the device pattern becomes finer, and the exposure apparatus is extremely expensive. It has become to.

  In recent years, the nanoimprint lithography (NIL) method using a fine concavo-convex pattern has attracted attention as an alternative. The nanoimprint method proposed by Chou et al. In Princeton University in 1995 is expected as a technique capable of forming a fine pattern having a high resolution of about 10 nm while the apparatus price and materials used are inexpensive.

  In the nanoimprint method, a template with a nanometer-sized uneven pattern formed on the surface in advance is pressed against a transfer material such as a resin applied and formed on the surface of the substrate to be mechanically deformed to precisely transfer the uneven pattern, This is a technique for processing a substrate to be processed using a patterned nanoimprint material as a resist mask. Once the template is made, the nanostructure can be easily and repeatedly molded, so that high throughput is obtained and it is economical, and since it is a nano-processing technology with less harmful waste, not only semiconductor devices in recent years, Applications in various fields are being promoted.

  As such a nanoimprint method, a thermal nanoimprint method in which a concavo-convex pattern is transferred by heat using a thermoplastic resin, a photo nanoimprint method in which a concavo-convex pattern is transferred by ultraviolet rays using a photocurable material, and the like are known. As the transfer material, a thermoplastic resin is used in the thermal nanoimprint method, and a photocurable material such as a photocurable resin is used in the optical nanoimprint method. The optical nanoimprint method can transfer patterns at room temperature with a low applied pressure, and does not require a heating / cooling cycle like the thermal nanoimprint method and does not cause dimensional changes due to the heat of the template or resin. It is said that it is excellent in terms of sex. Hereinafter, in the present invention, the optical nanoimprint method is simply referred to as nanoimprint method.

  FIG. 5 is a process cross-sectional view showing pattern formation by a conventional nanoimprint method. As shown in FIG. 5A, first, a template 50 having a pattern to be transferred is prepared. On the other hand, a low-viscosity photocurable resin 52 is applied on the substrate 51 to be processed.

  Next, the concavo-convex pattern of the template 50 is brought into contact with the photocurable resin 52 on the substrate 51 to be pressed, and light (ultraviolet light) 53 is applied while the template 50 is pressed as shown in FIG. Is applied to cure the photocurable resin to obtain a cured photocurable resin 54.

  Next, as illustrated in FIG. 5C, the template 50 is released from the cured photocurable resin 54. After the mold release, a transfer pattern is formed by the photocurable resin 54 on the substrate 51 to be processed.

  In the nanoimprint method, the portion of the photocurable resin 54 corresponding to the convex portion of the template 50 remains as a thin remaining film on the substrate 51 to be processed. Therefore, when it is necessary to expose the surface of the substrate 51 to be processed, FIG. As shown in (d), the remaining film is removed by ion etching using oxygen gas or the like. Next, the substrate to be processed is etched using the photocurable resin as a mask to obtain a substrate to be processed 55 on which a transfer pattern is formed as shown in FIG.

  Templates used in the nanoimprint method are required to have pattern dimension stability, chemical resistance, processing characteristics, and the like. In the nanoimprint method, the pattern shape of the template must be faithfully transferred to a transfer material such as a resin. For example, in the case of the nanoimprint method, a quartz glass substrate that generally transmits ultraviolet light used for photocuring. Is used in the template.

  Conventionally, as a method for producing a nanoimprint template, an electron beam resist is applied to the entire surface of a substrate serving as a template, an electron beam drawing is performed on the electron beam resist, a resist pattern is formed, and the substrate is formed using the resist pattern as an etching mask. A method of manufacturing a mold by etching to form a concavo-convex pattern is used.

  However, drawing of a fine pattern with an electron beam takes a long time to draw using an expensive drawing apparatus, which raises the problem of increasing the manufacturing cost of the template. In addition, if foreign matter is mixed in the interface between the template and the transfer target during nanoimprinting, both of them will be damaged greatly, and the damaged mold cannot be reused normally. There was a problem that the produced expensive template was lost.

  Therefore, a replica template manufacturing method has been proposed in which a template manufactured by electron beam lithography is used as a master template as a master template, and a replica template (hereinafter referred to as a replica template) is manufactured from the master template by a nanoimprint method (for example, Patent Literature 1 to Patent Literature 4). This replica template is used for normal nanoimprint on a wafer substrate or the like. Since it is manufactured by the nanoimprint method, the manufacturing cost can be reduced. If multiple replica templates are prepared, the problem of template damage can be dealt with, and the nanoimprint production line using the template can be made into multiple lines. There are advantages. Furthermore, when producing master templates and replica templates with fine patterns, it is advantageous for maintenance and management of pattern accuracy, such as processing and inspection, by using a conventional photomask manufacturing apparatus in processes other than those specific to nanoimprinting. There is an advantage that the manufacturing cost can be reduced.

Japanese Patent No. 4671860 Japanese Patent No. 4630886 JP 2011-199052 A US2010 / 0092599A1

  However, the replica template manufacturing method described in Patent Documents 1 to 3 has no description regarding the size of the substrate to be used, and when the described manufacturing method is performed using a thick substrate, the master template adhered after nanoimprinting In many cases, it is difficult to release the substrate and the substrate to be transferred. In this release process, there are problems such as defects in the transfer pattern and damage to the master template and replica template. The manufacture of was not easy. The replica template manufacturing method described in Patent Document 4 describes a method of thinning a part of the substrate on the transfer substrate side, but does not describe the size and configuration of the substrate related to the master template and the replica template. Not.

  Therefore, the present invention has been made in view of the above problems. That is, the object of the present invention is to utilize the advantages that it is advantageous for maintenance and management of pattern accuracy and can reduce the manufacturing cost by using a conventional photomask manufacturing apparatus in a process other than the manufacturing process peculiar to nanoimprint. However, in the replica template manufacturing method of manufacturing a replica template using the master template by the nanoimprint method, it is easy to release the master template and the substrate to be transferred after nanoimprinting. An object of the present invention is to provide a replica template manufacturing method in which damage to the replica template is unlikely to occur.

  In the conventional replica template manufacturing method in which a replica template is manufactured by a nanoimprint method using a conventional photomask substrate and a manufacturing apparatus in a process other than the manufacturing process peculiar to nanoimprint, As one of the reasons why it is difficult to release from the transfer substrate, in nanoimprinting with two thick substrates, it is difficult to separate from the edge of the substrate because the substrate hardly deforms at the time of release, and when the transfer pattern area is wide, Focusing on the fact that the force at the time of mold release increases and difficult pattern transfer is difficult, making the structure that the substrate undergoes constant deformation, and limiting the transfer pattern area enables good pattern transfer. Is. In this case, it is necessary to process the back surface of either the master template and the substrate to be transferred, or both substrates, but in order to avoid pattern defects during back surface processing, the master template is not processed and the pattern is formed. The present invention has been completed by finding that it is desirable to process an untransferred substrate before the imprint process.

  In order to solve the above-described problem, a replica template manufacturing method according to the first aspect of the present invention provides a first main surface of a transfer substrate having a first main surface and a second main surface. A photocurable resin layer is formed on a surface, the photocurable resin layer and a master template having a concavo-convex pattern are brought into close contact with each other, pressed, irradiated with light to cure the photocurable resin layer, and the master The template is released from the cured photocurable resin layer, the cured photocurable resin layer is formed on the first main surface of the transferred substrate, and the cured photocurable resin layer and the transferred image are transferred. In the replica template manufacturing method of etching a substrate to form a concavo-convex transfer pattern on the first main surface of the transferred substrate, the master template has a concavo-convex pattern formed on a parallel flat quartz glass substrate. The transfer substrate has a convex step structure in which the pattern region of the first main surface forming the transfer pattern is higher than the surroundings on the light-transmitting substrate, and the first main surface has The opposing second main surface has a depression that overlaps with the pattern region of the first main surface and has a larger area than the pattern region of the first main surface, and the convex stepped structure is And a step of forming a photocurable resin layer on the first main surface of the substrate to be transferred and forming a photocurable resin layer on the first main surface of the substrate to be transferred. The first main surface side is arranged on the top side, the second main surface side of the transferred substrate is arranged on the ground side, the field edge is defined, and the convex step structure of the transferred substrate is The transfer pattern is formed by forming the photo-curing resin layer.

  The replica template manufacturing method according to the second aspect of the present invention is the replica template manufacturing method according to the first aspect, wherein the area of the convex step structure is the first of the light-transmitting substrate. 10% or less of the area of the main surface of 1 and 0.5% or more.

  A replica template manufacturing method according to a third aspect of the present invention is the replica template manufacturing method according to the first or second aspect, wherein the master template has a size of 6 inches square and a thickness of 0. .25 inch quartz glass substrate.

  The replica template manufacturing method according to the invention described in claim 4 of the present invention is the replica template manufacturing method according to any one of claims 1 to 3, wherein the indentation is a square, It has a geometric shape selected from a group of geometric shapes consisting of a rectangle, a circle and an ellipse.

  The replica template manufacturing method according to the invention described in claim 5 of the present invention is the replica template manufacturing method according to any one of claims 1 to 4, wherein the recess is the first 1 has a bottom surface parallel to the main surface, and the distance from the first main surface to the bottom surface of the recess is smaller than half the thickness of the substrate to be transferred.

  The replica template manufacturing method according to the invention described in claim 6 of the present invention is the replica template manufacturing method according to any one of claims 1 to 5, wherein the substrate to be transferred is: A metal film is formed on the first main surface.

  A method for manufacturing a replica template according to a seventh aspect of the present invention is the method for manufacturing a replica template according to the sixth aspect, wherein the metal film is chromium or a compound containing chromium. Is.

  The replica template manufacturing method according to an eighth aspect of the present invention is the replica template manufacturing method according to any one of the first to seventh aspects, wherein: Is transferred to the photocurable resin layer of the substrate to be transferred, by applying pressure or decompression to the recess portion of the substrate to be transferred using a fluid, while changing the shape of the recess portion to a curved shape. A transfer pattern is formed.

  The replica template manufacturing method according to the ninth aspect of the present invention is the replica template manufacturing method according to any one of the first to eighth aspects, wherein the uneven pattern of the master template is Is transferred to the photocurable resin layer of the substrate to be transferred, by applying pressure only to the four side surfaces of the master template, thereby forming a transfer pattern while changing the size of the pattern of the master template. It is characterized by this.

  According to the replica template manufacturing method using the nanoimprint method of the present invention, the pattern region of the first main surface of the substrate to be transferred has a step structure higher than the surroundings, and the first main surface is formed on the second main surface. By using a substrate to be transferred that has a depression that overlaps the pattern region of the surface and has a larger area than the pattern region of the first main surface, it is easy to release the master template and the substrate to be transferred after nanoimprinting. There is an effect that the transfer pattern has few defects and the master template and the replica template are hardly damaged.

  Since the replica template produced by the production method of the present invention has few defects in the template production process, a high-quality replica template having an inverted pattern of the master template can be obtained.

It is process sectional drawing which shows one Embodiment of the manufacturing method of the replica template of this invention. It is process sectional drawing which shows the manufacturing method of the replica template of this invention following FIG. It is a plane schematic diagram which shows an example of the to-be-transferred substrate used for the manufacturing method of the replica template of this invention shown in FIG. It is process sectional drawing which shows an example of the manufacturing process of the to-be-transferred substrate used for the manufacturing method of the replica template of this invention. It is process sectional drawing which shows the pattern formation by the conventional nanoimprint method.

  Hereinafter, based on drawings, the manufacturing method of the template for nanoimprinting concerning the embodiment of the present invention is explained in detail.

(Embodiment 1)
FIG. 1 and subsequent FIG. 2 are process cross-sectional views illustrating an embodiment of the replica template manufacturing method of the present invention.

  First, as shown in FIG. 1A, a transfer substrate 10 serving as a replica template is prepared by the manufacturing method of the present invention. FIG. 1A is a schematic cross-sectional view of an example of the transfer substrate 10. FIG. 3 is a schematic plan view of an example of the transfer substrate 10 used in the replica template manufacturing method of the present invention shown in FIGS. 1 and 2, and a cross-sectional view taken along line AA in FIG. 3 is shown in FIG. It is.

  In the replica template manufacturing method of the present invention, the transferred substrate 10 has a first main surface 11 and a second main surface on a parallel flat quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches. 12, the pattern region 13 of the first main surface 11 forming the transfer pattern has a convex step structure (also referred to as a mesa structure) 14 higher than the surroundings, and the first main surface 11 The second main surface 12 opposite to the first main surface 12 has a recess 15 that overlaps with the pattern region 13 of the first main surface and has a larger area than the pattern region 13 of the first main surface. The step structure is located at the center of the 6-inch square quartz glass substrate, and the area is 10% or less and 0.5% or more of the area of the first main surface of the 6-inch square quartz glass substrate. It is what I did.

  Unlike the conventional replica template manufacturing method, it is difficult to release the mold after imprinting between the master template and the substrate to be transferred that are thick, whereas the substrate to be transferred in the replica template manufacturing method of the present invention 10 has an indentation 15 that overlaps with the pattern region 13 and has a larger area than the pattern region 13, so that when the substrate 10 is released from the master template after imprinting, the transfer substrate 10 is deformed to some extent. It becomes possible to pull away from the end of 10. In addition, the substrate to be transferred 10 has an effect of extruding air around the uneven pattern even at the time of imprinting, improves the adhesion at the time of transfer with the master template, and is a photocurable resin in which the occurrence of defects is suppressed. The pattern can be transferred. With respect to this effect, the same effect can be obtained when imprinting on the transfer substrate using the produced replica template.

  As described above, in order to easily start the mold release, it is only necessary to provide a recess in at least one of the master template and the transfer substrate. However, since the master template forms a pattern by electron beam lithography and uses a mask manufacturing apparatus for dry etching or the like, it is desirable that the master template has a substrate structure that can easily be adapted to a conventional photomask manufacturing apparatus or mask process. Further, if the recess is provided in the master template, there arises a problem that defects in the master template increase due to an increase in the manufacturing process. Therefore, in the replica template manufacturing method of the present invention, no recess is provided on the master template side, but a recess is provided on the transfer substrate side.

  Therefore, in the replica template manufacturing method of the present invention, the master template is formed on a parallel flat quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches as a substrate structure suitable for a photomask manufacturing apparatus and a mask process. A master template is used in which a concavo-convex pattern is formed on the surface and does not have a step structure and a depression. The quartz glass substrate having the above-mentioned size is used with a photomask and has a high quality.

  In the replica template manufacturing method of the present invention, the transferred substrate 10 has a convex step structure (mesa structure) 14 in which the pattern region 13 of the first main surface 11 is higher than the surroundings, and the convex step structure. This prevents the transfer substrate part other than the pattern area from coming into contact with the master template at the time of nanoimprinting, and also makes it easier to release the two by reducing the contact part. Yes. The convex step structure 14 is preferably provided at the center of the first main surface of the substrate 10 to be transferred so as to perform uniform pattern transfer during nanoimprinting and not damage the transfer pattern during release. Similarly to the depression, when the imprint of a plurality of shots is performed on the substrate to be transferred using the produced replica template, a favorable pattern can be formed without causing interference with the previously imprinted pattern.

  In the present invention, a conventionally known spin coating method or inkjet coating method is used as a coating method of the photocurable resin, but the photocurable resin is controlled by controlling the coating amount by dividing the field into predetermined regions. An inkjet method that can be applied is more preferable. This is because in the nanoimprint method, it may be necessary to change the required amount of the photocurable resin to be applied according to the pattern density to be transferred. One field corresponds to one shot size for nanoimprinting.

  Furthermore, by forming the convex step structure 14, when forming the photocurable resin layer on the first main surface 11 of the substrate 10 to be transferred, the field edge is defined and the convex step is formed by the ink jet method. It is easy to apply a photocurable resin only on the structure 14 to form a uniform coating layer.

  The area of the convex step structure 14 of the transfer substrate 10 is related to the magnitude of the release force in the release step. As for mold release, it is generally known to perform a mold release process on the master template side. Although the magnitude of the release force varies depending on the material for the release treatment, when a material having higher water repellency is used, the capillary force is reduced, which may cause unfilled defects. Therefore, it is necessary to control water repellency to such an extent that unfilled defects do not occur. On the other hand, the magnitude of the release force changes in proportion to the area to be transferred. Since the force becomes stronger as the area becomes larger, the photocurable resin layer tends to break. Although it depends on the material and shape of the substrate, in a system using a 6-inch square quartz glass substrate, it is desirable that the transfer area is approximately 5 cm square or less. Therefore, in the present invention, the area of the convex step structure 14 is 10% or less of the area of the first main surface of the 6-inch square quartz glass substrate.

  On the other hand, the lower limit of the area of the convex step structure 14 relates to an error in film thickness in the coating process of the photocurable resin layer. That is, when a photocurable resin is applied using an ink jet apparatus, the amount of resin to be ejected by ink jet is limited, so that it is difficult to control the liquid amount to a desired value in a small area. Moreover, it is difficult to provide a margin for fluctuations in the liquid volume. Therefore, it is desirable to apply 1000 shots or more with an ink jet apparatus, and when a liquid amount of 3 picoliters is applied with 1 shot, it is desirable that the application is approximately 1 cm square or more. Therefore, in the present invention, the area of the convex step structure 14 is 0.5% or more of the area of the first main surface of the 6-inch square quartz glass substrate.

  The shape of the recess 15 of the transferred substrate 10 used in the replica template manufacturing method of the present invention has a shape selected from a group of geometric shapes including a square, a rectangle, a circle, and an ellipse.

  Further, the recess 15 of the transfer substrate 10 includes a bottom surface 16 parallel to the first main surface 11, and the distance (d) from the first main surface 11 to the bottom surface 16 of the recess is the thickness of the transfer substrate 10. It is preferably less than half of (t). By reducing the thickness of the substrate in the indentation region to be smaller than half the thickness (t) of the transferred substrate 10, when the master template and the transferred substrate are released after nanoimprinting, the transferred substrate 10 is removed. This is because elastically deforms and becomes easy to release.

  On the other hand, the lower limit of the distance (d) from the first main surface 11 to the bottom surface 16 of the indentation varies depending on the material of the substrate to be transferred, the indentation region, the shape / area of the step structure, etc., but retains the strength as a template. Therefore, a certain thickness or more is necessary. For example, when a circular recess having a diameter of 60 mm is provided on a 0.25 inch thick quartz glass substrate, the distance (d) is preferably at least 0.5 mm or more.

  In the replica template manufacturing method of the present invention, it is preferable that the transferred substrate 10 has a metal film formed on the first main surface 11 including the convex stepped structure 14. When the transfer substrate 10 is dry-etched to form a transfer pattern, the cured photocurable resin pattern alone may not have sufficient etching resistance. Therefore, it is preferable to use a method in which the cured photocurable resin pattern is converted into a metal film pattern, and the transferred substrate 10 is dry-etched using the metal film as a hard mask.

  As the metal film, chromium or a compound containing chromium (chromium oxide, chromium nitride, chromium oxynitride, etc.) having high resistance to a fluorine-based gas used when etching a quartz glass substrate or the like to be transferred substrate 10 is preferable. The film thickness is in the range of about 10 nm to 80 nm.

(Transfer substrate manufacturing method)
Here, a manufacturing method of the transfer substrate 10 used in the manufacturing method of the replica template of the present invention will be described with reference to the drawings. FIG. 4 is a process cross-sectional view illustrating an example of a manufacturing process of a transfer substrate used in the replica template manufacturing method of the present invention. In FIG. 4, the same reference numerals are used to indicate the same parts as in FIG.

  As shown in FIG. 4A, a transfer substrate 10a having a first main surface 11 and a second main surface 12 is prepared. As described above, in the present invention, the substrate 10a to be transferred is a parallel flat quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches.

  Next, as shown in FIG. 4B, a transfer substrate 10 b having a convex step structure (mesa structure) 14 higher than the surrounding is formed on the first main surface 11. As will be described later, a pattern region 13 is provided on the step structure 14. The convex step structure 14 can be formed by wet etching using a hydrofluoric acid aqueous solution with a predetermined region masked in advance with a resist pattern or a pattern of a resist and a metal film such as chromium. The height of the convex step structure is provided in the range of several μm to several tens of μm. The area of the pattern region 13 having a convex step structure depends on a required one-field pattern, but is set to a rectangular shape of several tens mm × several tens mm, for example.

  Next, the second main surface 12 of the substrate to be transferred 10b is processed by a conventionally known method such as counterboring to form a recess 15, and as shown in FIG. 4 (c), the first main surface 12 11 pattern region 13 has a convex step structure 14 higher than the surrounding, and overlaps with the second main surface 12 opposite to the first main surface 11 with the pattern region 13 of the first main surface. In addition, the transfer substrate 10 having the depression 15 having a larger area than the pattern region 13 on the first main surface is formed.

  Examples of the material constituting the substrate 10 to be transferred include optically polished quartz glass, soda glass, fluorite, and calcium fluoride that transmit light used for nanoimprinting, and quartz glass is used as a photomask substrate. It is more preferable because it has a high track record of use and stable quality, and can be integrated into a light-transmitting structure by providing a step structure, a dent and a concave / convex pattern, and can form a fine concave / convex pattern with high accuracy. .

  Again, returning to FIG. As shown in FIG. 1B, a photocurable resin layer 17 is formed on the convex stepped structure 14 of the first main surface 11 of the prepared substrate 10 to be transferred. On the other hand, a master template 18 provided with an uneven pattern 19 to be transferred is prepared.

  Next, as shown in FIG. 1 (c), the photocurable resin layer 17 on the convex step structure 14 of the substrate 10 to be transferred and the concave / convex pattern 19 of the master template 18 are brought into close contact with each other and pressed, and light ( UV light) 20 is irradiated to cure the photocurable resin layer.

  Next, the master template 18 is released from the cured photocurable resin. After the mold release, as shown in FIG. 1D, a transfer pattern is formed by the cured photocurable resin 21 on the convex stepped structure 14 of the first main surface 11 of the substrate 10 to be processed.

  In the nanoimprint method, a portion of the photocurable resin corresponding to the convex portion of the concave / convex pattern of the master template 18 remains as a thin residual film on the substrate to be processed, so oxygen gas was used as shown in FIG. The thin residual film is removed by ion etching or the like to form a cured photocurable resin pattern 22.

Next, using the photo-curable resin as a mask, the substrate to be processed is dry-etched using CF ₄ gas or the like, and the unevenness is transferred to the pattern region 13 of the first main surface 11 as shown in FIG. A replica template 24 on which the pattern 23 is formed is obtained.

  In the present invention, the depth of the concave portion of the concavo-convex pattern 23 formed by digging the first main surface of the transferred substrate 10 is a desired resin pattern of a photocurable resin pattern formed on a nanoimprint substrate such as a wafer substrate. Depending on the thickness of the concave / convex pattern, for example, the concave / convex pattern 23 has a concave depth of 20 nm to 100 nm.

(Reverse pattern)
In the manufacturing method of the present invention, as shown in FIG. 2 (f), the uneven pattern 23 of the obtained replica template 24 is inverted in the uneven relation and the left-right relation of the uneven pattern 19 of the master template 18 shown in FIG. It becomes a pattern. Therefore, if the master template pattern data is converted in advance corresponding to the required replica template pattern, and the replica template is produced using a master template having a pattern in which the concavo-convex relationship and the left-right relationship are reversed, it is necessary. A replica template having a desired pattern can be obtained. The method of converting the pattern data in advance is a preferable method in which the replica template manufacturing process is not burdened and the occurrence of defects does not increase.

(Embodiment 2)
In the manufacturing method of the present invention, when transferring the concave / convex pattern of the master template to the photocurable resin layer of the transferred substrate, the recessed portion is formed by applying pressure or reduced pressure to the recessed portion of the transferred substrate using a fluid. It is a preferred embodiment that the transfer pattern is formed while changing the curved shape. This is because by changing the curved shape of the indented portion, the adhesion between the master template and the transferred substrate at the time of nanoimprinting can be improved and can be easily separated at the time of mold release.

  In nanoimprinting, when the master template and the substrate to be transferred are in close contact, part of the gas such as air that exists between the two loses the escape field and remains between the patterns or in the viscous photocurable resin. Small regions called gas pockets may be formed. The above gas or gas pocket causes defects in the transfer pattern or causes pattern distortion.

  By using the method of forming a transfer pattern while changing the curved shape of the indented portion of this embodiment, gas confinement or generation of gas pockets between the master template and the substrate to be transferred and between the patterns is reduced. And pattern distortion can be prevented.

  In this embodiment, gas or liquid is used as the fluid, but gas that is easy to handle is more preferable. Nitrogen gas, helium gas, air, etc. are used as gas.

(Embodiment 3)
In the production method of the present invention, when transferring the concave / convex pattern of the master template to the photocurable resin layer of the substrate to be transferred, pressure is applied only to the four side surfaces of the master template, and the pattern size of the master template is set. Transferring while changing is the preferred embodiment. This is because, by applying pressure to the side surface of the master template and transferring the pattern by changing the size of the pattern of the master template, it is possible to correct the dimension of the pattern transferred to the substrate to be transferred.

  By changing the size of the pattern of the master template by applying pressure in this embodiment, the distance between each part of the master template and the substrate to be transferred is slightly changed, and gas confinement or gas pocket generation between patterns is reduced. This shows the effect of preventing the occurrence of defects and pattern distortion.

As described above, the replica template manufacturing method of the present invention has a convex step structure in which the pattern region of the first main surface of the substrate to be transferred is higher than the surroundings, and the second main surface has the first step described above. In the manufacture of a replica template, by using a substrate to be transferred that has a recess that overlaps the pattern region of the first main surface and has a larger area than the pattern region of the first main surface, It is advantageous in that it can be easily released from the transfer substrate, the transfer pattern has few defects, and the master template and replica template are hardly damaged. In addition, the replica template manufactured by the manufacturing method of the present invention avoids a failure at the time of releasing, so that the transfer pattern has few defects and is of high quality.
Next, an example explains the present invention.

Example 1
As a substrate to be transferred for a replica template, a pattern forming region (pattern region) is formed in the center of the first main surface of a synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches from the periphery. Has a convex step structure (mesa structure) having an area of 25 mm × 30 mm which is 30 μm higher, overlaps with the pattern region of the first main surface on the second main surface, and more than the pattern region of the first main surface. A substrate having a large area and a circular recess having a diameter of 60 mm was prepared. The thickness of the quartz glass substrate where the depression was formed was 1 mm.

On the other hand, as a master template for imprinting, an electron beam resist is applied with a thickness of 200 nm on one main surface of a synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches, followed by electron beam drawing and development. Then, after forming a resist pattern, the quartz glass was dry-etched with CF ₄ gas, and then the resist pattern was peeled off to produce a master template in which an uneven pattern was formed on the quartz glass.

  The depth of the concave portion of the pattern of the produced master template was 50 nm. The patterns were two patterns: a plurality of line and space patterns with a recess width of 40 nm and a pitch of 80 nm, and a plurality of line and space patterns with a recess width of 30 nm and a pitch of 60 nm. The master template pattern is obtained by setting in advance a pattern obtained by inverting the concavo-convex relationship and the left-right relationship of the required replica template pattern.

  Next, the application amount of the photo-curable resin for nanoimprinting on the transfer substrate was changed for each pattern by an inkjet method, and one field was applied on the convex step structure. Subsequently, using the master template, the photocurable resin is pressed against the photocurable resin on the substrate to be transferred and irradiated with ultraviolet light for exposing the photocurable resin through the master template to photocure the photocurable resin. I let you.

  Next, a release force was applied downward from two opposing end faces of the transfer substrate to release the transfer substrate from the master template. The transferred substrate has a dent, and can be separated from the end surface of the transferred substrate by being deformed to some extent. The uneven pattern of the photocurable resin is transferred onto the substrate to be transferred, and the photocurable resin pattern does not ooze out from the field on the convex step structure, and the photocurable resin is hardened by the photocurable resin cured in the field. A pattern with a uniform film thickness of 50 nm and a remaining film thickness of 15 nm was formed.

  Next, the photocurable resin remaining as a thin remaining film on the substrate to be processed is removed by performing an ion etching process using oxygen gas, and the photocurable resin having a height of 35 nm which is cured on the substrate to be processed is cured. A resin pattern was formed.

Next, the quartz glass of the substrate to be processed is dry-etched using CF ₄ gas with the photocurable resin pattern as a mask, and the irregularities made of quartz glass are formed on the pattern region on the convex step structure of the first main surface. A replica template having a transfer pattern was obtained. The pattern of the replica template is a pattern in which the concavo-convex relationship and the left-right relationship are reversed from the pattern of the master template, and a plurality of lines and spaces having a concave depth of 50 nm, a concave width of 40 nm, and a pitch of 80 nm on the convex step structure. It has two patterns: a pattern and a plurality of line and space patterns having a recess width of 30 nm and a pitch of 60 nm.

  By repeating the above replica template manufacturing method, a plurality of replica templates were produced from a single master template, but neither the master template nor the replica template was damaged, and the wafer was manufactured using the replica template. When nanoimprinting on a substrate or the like, there were few defects and a high-quality transfer pattern was obtained.

(Example 2)
A substrate to be transferred having the same size and shape as in Example 1 was produced.
Next, chromium was formed by sputtering on the first main surface including the convex step structure of the transferred substrate to form a chromium film having a thickness of 10 nm. Next, using the same master template as in Example 1, a photocurable resin layer was applied and formed on chromium on the first main surface of the substrate to be transferred in the same manner as in Example 1, and this photocurable resin layer was formed. And the master template are brought into close contact with each other and pressurized, irradiated with ultraviolet light to cure the photocurable resin layer, then the master template is released from the photocurable resin layer, and the cured photocurable resin layer is etched. Thus, a photocurable resin pattern was formed.

Next, using the photocurable resin pattern as a mask, the chromium film is patterned by dry etching with a mixed gas of chlorine and oxygen, and after removing the photocurable resin pattern with oxygen plasma, the patterned chromium film is used as a mask. A replica template in which a transfer substrate is dry-etched with CF ₄ gas, and then a chromium film pattern is removed by wet etching with an aqueous solution of ceric ammonium nitrate to form an uneven transfer pattern on the first main surface of the transfer substrate. Formed.

  In the manufacturing method of this example, since the chromium film has sufficient etching resistance when dry-transferring the transfer substrate, a highly accurate uneven pattern made of quartz glass was obtained.

(Example 3)
As a substrate to be transferred for a replica template, an area 30 mm × 30 mm which is 20 μm higher than the surrounding area as a pattern region at the center of the first main surface of a synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches. A convex stepped structure, a square shape with a side of 60 mm that overlaps with the pattern region of the first main surface on the second main surface and has a larger area than the pattern region of the first main surface. A substrate with indentations was prepared. The thickness of the quartz glass substrate where the depression was formed was 1 mm.

  Next, using the same master template as in Example 1, a photocurable resin layer was applied and formed on the first main surface of the substrate to be transferred in the same manner as in Example 1, and this photocurable resin layer and the master were then formed. The template is brought into intimate contact with pressure, while nitrogen gas is allowed to flow through the indented portion of the substrate to be transferred, the pressure in the indented portion is set to 1.5 atm, and the indented portion is curved convexly toward the master template side. The photocurable resin layer was cured by being adhered and irradiated with ultraviolet light.

Subsequently, the pressure of the hollow portion was reduced to atmospheric pressure, the master template was released from the photocurable resin layer, and the cured photocurable resin layer was etched to form a photocurable resin pattern. The subsequent steps are the same as in Example 1, using the photocurable resin pattern as a mask, dry etching the quartz glass of the substrate to be processed using CF ₄ gas, and forming a convex step structure on the first main surface. A replica template in which an uneven transfer pattern made of quartz glass was formed in the upper pattern region was obtained.

  In the manufacturing method of this example, by changing the shape of the indented portion to a curved shape, the adhesion between the master template and the transferred substrate at the time of nanoimprinting was improved, and could be easily released at the time of release.

Example 4
A substrate to be transferred having the same size and shape as in Example 3 was produced.
Next, using the same master template as in Example 1, a photocurable resin layer was applied and formed on the first main surface of the transfer substrate in the same manner as in Example 1, and then the four sides of the master template were applied. While applying pressure to the side surface of the substrate, the master template was brought into close contact with the photocurable resin layer and the template was pressed to form a transfer pattern.

  In the manufacturing method of this example, the size of the pattern transferred to the transfer substrate was corrected to the minus side by about 2 nm by changing the size of the master template pattern by applying pressure to the side surface of the master template. A transfer pattern could be formed.

10, 10a Transfer target substrate 11 First main surface 12 Second main surface 13 Pattern region 14 Step structure (mesa structure)
15 Indentation 16 Bottom surface 17 Photocurable resin layer 18 Master template 19 Uneven pattern 20 Light (ultraviolet)
21 cured photocurable resin 22 cured photocurable resin pattern 23 uneven transfer pattern 24 replica template 50 template 51 substrate to be processed 52 photocurable resin 53 light (ultraviolet)
54 Cured Photocurable Resin 55 Processed Substrate with Transfer Pattern Formed

Claims (9)

A photocurable resin layer is formed on the first main surface of a transfer substrate having a first main surface and a second main surface, and the photocurable resin layer and a master template having a concavo-convex pattern are in close contact with each other And pressurizing, irradiating light to cure the photocurable resin layer, releasing the master template from the cured photocurable resin layer, and curing the first main surface of the substrate to be transferred A replica template is formed by forming a cured photocurable resin layer, etching the cured photocurable resin layer and the transferred substrate, and forming an uneven transfer pattern on the first main surface of the transferred substrate. In the method
The master template has a concavo-convex pattern formed on a quartz glass substrate in a parallel plane,
The transfer substrate has a convex step structure in which a pattern region of the first main surface forming the transfer pattern is higher than the surroundings on a light-transmitting substrate, and is relative to the first main surface. The second main surface has a depression that overlaps the pattern region of the first main surface and has a larger area than the pattern region of the first main surface, and the convex step structure is Located in the center of the first main surface of the light transmissive substrate,
In the step of forming a photocurable resin layer on the first main surface of the transfer substrate,
The first main surface side of the transfer substrate is disposed on the top side, the second main surface side of the transfer substrate is disposed on the ground side,
Define the field edge,
A replica template manufacturing method, wherein the photocurable resin layer is formed on the convex stepped structure of the transfer substrate to form the transfer pattern.   2. The replica template according to claim 1, wherein an area of the convex step structure is not more than 10% and not less than 0.5% of an area of the first main surface of the light-transmitting substrate. Manufacturing method.   The replica template manufacturing method according to claim 1, wherein the master template is a quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches.   4. The recess according to any one of claims 1 to 3, wherein the indentation has a geometric shape selected from a group of geometric shapes consisting of squares, rectangles, circles and ellipses. Replica template manufacturing method.   The recess has a bottom surface parallel to the first main surface, and a distance from the first main surface to the bottom surface of the recess is smaller than half of the thickness of the transferred substrate. The method for manufacturing a replica template according to any one of claims 1 to 4.   The replica template manufacturing method according to claim 1, wherein a metal film is formed on the first main surface of the substrate to be transferred.   The method for manufacturing a replica template according to claim 6, wherein the metal film is chromium or a compound containing chromium. When transferring the uneven pattern of the master template to the photocurable resin layer of the substrate to be transferred,
8. The transfer pattern is formed by changing the shape of the recessed portion into a curved shape by applying pressure or decompression using a fluid to the recessed portion of the substrate to be transferred. The method for manufacturing a replica template according to any one of the above. When transferring the uneven pattern of the master template to the photocurable resin layer of the substrate to be transferred,
The transfer pattern is formed while changing the size of the pattern of the master template by applying pressure only to the side surfaces of the four sides of the master template. A method for producing a replica template according to claim 1.

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