JP2014194960A - Template for nano imprint, pattern forming method using template for nano imprint, and method of manufacturing template for nano imprint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a template having a loop cutting structure in which loop cut occurring in a side wall transfer process is stably performed, and also to provide a pattern forming method utilizing the template and a method of manufacturing the template.SOLUTION: A template for nano imprint includes an uneven shaped transfer pattern on the substrate main surface. In an uneven shape, a first side wall has an inclined shape and a second side wall has a vertical shape.

Description

  The present invention relates to nanoimprint lithography for transferring and forming a fine concavo-convex pattern, and more particularly to a nanoimprint template, a pattern formation method using a nanoimprint template, and a method for manufacturing a nanoimprint template.

  In recent years, semiconductor devices require high-speed operation and low power consumption operation 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 that is essential for producing semiconductor device patterns has pointed out the limitations of the photolithography system due to the problem of the exposure wavelength as the device pattern becomes finer, and the exposure apparatus is extremely expensive. It is becoming.

  In recent years, the nanoimprint lithography (NIL) method using a fine concavo-convex pattern has attracted attention as an alternative. The nanoimprint lithography 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 imprint method, a template with a nanometer-sized concavo-convex pattern formed on the surface in advance is pressed against a material to be transferred such as resin formed on the surface of the substrate to be transferred, so that the concavo-convex pattern is precisely transferred. This is a technique for processing a transfer substrate using a patterned imprint 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 to various fields such as optical members and magnetic recording media are being promoted. Such imprinting methods include a thermal imprinting method in which a concavo-convex pattern is transferred by heat using a thermoplastic material, or a light that transfers a concavo-convex pattern by irradiating light such as ultraviolet rays using a photocurable material. The imprint method is known. The optical imprint method can transfer a pattern at a low applied pressure at room temperature, and does not require a heating / cooling cycle like the thermal imprint 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 productivity.

  In recent years, in order to meet the demand for further miniaturization, as a method for forming a semiconductor device pattern such as a semiconductor memory or a pattern for a template for nanoimprinting, a sidewall material film is formed on a sidewall of a pattern serving as a core material. A sidewall transfer process for forming and forming a fine pattern by etching using the sidewall pattern as a mask has been developed. In this sidewall transfer process, a closed loop (hereinafter referred to as a loop) structure is formed around the pattern serving as the core material. FIG. 20A is a plan view showing a state in which the sidewall material film 12 is deposited on the core material pattern 11 and the sidewall material film is entirely dug by etching back to expose the upper surface of the core material pattern and the surface of the transferred substrate. Unnecessary portions of the loop structure 13 generated at this time must be cut in a subsequent process.

  For example, Patent Document 1 describes a method of producing a nanoimprint template by a sidewall transfer process and cutting a loop on the template. Patent Document 2 describes that a template is manufactured by a side wall transfer process, the template is used for transfer to a wafer, and a loop is cut on the transferred wafer. FIG. 20B is a view after the loop structure is cut by a process such as photolithography to form the sidewall pattern 15 after removing the core material pattern in FIG. However, since the cutting operation of the loop increases the process load, a side wall transfer process that does not cause a loop has been proposed. Patent Document 3 proposes a method of cutting a loop during etch back by forming a slope at the end of a core material when using the sidewall transfer process method.

JP 2010-284922 A JP 2010-239209 A JP 2011-129756 A

  However, in the method of Patent Document 3, a loop cutting structure in which an end portion of a core material pattern has an inclined shape is manufactured by a photolithography method, and SRAF is provided at a pattern end portion of a photomask, and indirectly by the SRAF structure. An inclined shape is formed. In this photolithography method, the tilt shape is indirectly controlled using a small difference in exposure dose, so the material dependence is strong, and it is necessary to redesign the optimum pattern for each material. Further, since the inclined shape also changes with process variations such as exposure and development conditions, there is a problem that stable loop cutting is difficult. In particular, it has been difficult to stably produce the inclination angle, width, length, and the like of the inclined structure at the pattern end. Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a template and a template having a loop cutting structure that can stably cut a loop that occurs during the sidewall transfer process. The object is to provide a pattern forming method and a template manufacturing method.

  In order to solve the above problems, the present invention uses nanoimprint lithography in a pattern transfer method of a loop cutting structure. The template for nanoimprinting according to one embodiment of the present invention includes an uneven transfer pattern on the substrate main surface, and the uneven shape has a first side wall having an inclined shape, and a second side wall has It has a vertical shape.

A template for nanoimprinting according to another embodiment of the present invention includes a concavo-convex shape transfer pattern on a substrate main surface, and the concavo-convex shape has a step shape on a first side wall,
The second side wall has a vertical shape.

The pattern forming method according to the embodiment of the present invention includes a step of making the nanoimprint template light-transmissive and dropping a photocurable film on a transfer substrate by inkjet,
A process of irradiating light through the nanoimprint template to cure the photocurable film in a state where the uneven pattern transfer pattern of the nanoimprint template is pressed against the photocurable film, and the nanoimprint template and the coating Separating the transfer substrate;
The pattern formed by curing the photo-curing film is used as a core material pattern, the side wall material film is deposited by ALD method, and the loop structure of the side wall material film is cut by etch back, and the side wall pattern is formed on the side wall of the core material pattern. Forming the step.

  A method of manufacturing a nanoimprint template according to an embodiment of the present invention includes: preparing a substrate having a hard mask; processing the hard mask on the substrate; partially opening the hard mask; and opening the hard mask. A hard mask processing step for forming a hard mask opening around the edge, a resist forming step for providing a resin resist on the substrate, and the periphery of the hard mask opening are covered with the resist at the opening edge of the hard mask. A resist opening forming step of forming a resist opening so as to have a second side exposed from the resist, except for a portion covered by the resist covering the first side and the first side; And a substrate etching process for etching the substrate exposed from the hard mask opening and the resist opening to form a recess, and covering the first side The end face on the hard mask opening of the gate has an inclined shape, and the inclined resist forms an inclined shape on the side wall of the first side, and the hard side exposed from the resist on the side wall of the second side. A vertical shape is formed by the mask opening end.

  A method for manufacturing a template for nanoimprinting according to another embodiment of the present invention includes a step of preparing a substrate having a hard mask, processing the hard mask on the substrate, partially opening the hard mask, and opening the hard mask. A hard mask processing step for forming a hard mask opening around the edge, a resist forming step for providing a resin resist on the substrate, and the periphery of the hard mask opening are covered with the resist at the opening edge of the hard mask. A resist opening forming step of forming a resist opening so as to have a second side exposed from the resist except for a portion covered by the resist covering the first side and the first side; Etching the substrate exposed from the hard mask opening and the resist opening to form a recess, a substrate etching step, reducing the resist surface, A resist surface treatment step for receding the dyst side wall, and alternately repeating the substrate etching step and the resist surface treatment step, forming a step shape on the side wall of the first side, and forming a step shape on the side wall of the second side. Is characterized in that a vertical shape is formed by the open end of the hard mask exposed from the resist.

  According to the nanoimprint template of the present invention, it is possible to stably transfer the loop cutting structure. Moreover, in the pattern formation method using the nanoimprint template of the present invention, loop cutting can be stably performed. Moreover, according to the method for producing a template for nanoimprinting of the present invention, a template having a loop cutting structure can be produced.

It is the cross-sectional schematic diagram which showed the structure of the template of this invention. It is the plane schematic diagram which showed the structure of the template which concerns on the 1st Embodiment of this invention. It is the cross-sectional schematic diagram which showed the structure of the template which concerns on the 1st Embodiment of this invention, and is the alpha-alpha and AA sectional view taken on the line of FIG. It is the cross-sectional schematic diagram which showed the to-be-transferred material and the to-be-transferred substrate imprinted with the template which concerns on the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows the process flow of a side wall transcription | transfer process, Fig.5 (a) is FIG. 4ZZ sectional view taken on the line. It is the cross-sectional schematic diagram which showed the structure of the template which concerns on the 1st modification in the 1st Embodiment of this invention, and is the sectional view on the AA line of FIG. It is the cross-sectional schematic diagram which showed the to-be-transferred material and the to-be-transferred substrate imprinted with the template which concerns on the 1st modification in the 1st Embodiment of this invention. It is the plane schematic diagram which showed the structure of the template which concerns on the 2nd modification in the 1st Embodiment of this invention. FIG. 9 is a schematic cross-sectional view showing a configuration of a template according to a second modification in the first embodiment of the present invention, and is a cross-sectional view taken along line BB in FIG. 8. It is the plane schematic diagram which showed the structure of the template which concerns on the 2nd Embodiment of this invention. FIG. 11 is a schematic cross-sectional view showing a configuration of a template according to a second embodiment of the present invention, and is a cross-sectional view taken along line γ-γ and CC in FIG. 10. It is the cross-sectional schematic diagram which showed the to-be-transferred material and the to-be-transferred substrate imprinted with the template which concerns on the 2nd Embodiment of this invention. It is the cross-sectional schematic diagram which showed the 1st manufacturing method of the template of this invention. It is a top view of FIG.13 (c) which concerns on the 1st manufacturing method of the template of this invention. It is a top view which shows the modification of FIG. 14 which concerns on the 1st manufacturing method of the template of this invention. It is the cross-sectional schematic diagram which showed the 2nd manufacturing method of the template of this invention. It is a top view of FIG.16 (b) which concerns on the 2nd manufacturing method of the template of this invention. It is a plane schematic diagram which shows the modification of arrangement | positioning or pattern of the loop cutting structure which concerns on the manufacturing method of the template of this invention. It is the cross-sectional schematic diagram which showed the 3rd manufacturing method of the template of this invention. It is a schematic diagram which shows a prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention uses nanoimprint lithography as a transfer method of a loop cutting structure, and refer to the drawings for embodiments of the nanoimprint template, the pattern formation method using the nanoimprint template, and the nanoimprint template manufacturing method of the present invention. While explaining.

[Template for nanoimprint]
The nanoimprint template (hereinafter referred to as template) of the present invention will be described.
FIG. 1 is a cross-sectional view schematically showing the configuration of the template of the present invention. On the substrate main surface 20 of the substrate 10, a pattern of the concavo-convex shape 30 for transfer is formed. The concavo-convex shape for transfer has a convex portion 40 and a concave portion 50, and forms a circuit pattern for a semiconductor, a recording element pattern for a magnetic recording medium, and the like.

  When used for optical nanoimprinting, the substrate is a light-transmitting substrate and the material is, for example, a glass substrate such as quartz glass, soda glass, fluorite, calcium fluoride substrate, magnesium fluoride substrate, acrylic glass, polycarbonate substrate, polypropylene It can create from resin substrates, such as a board | substrate and a polyethylene substrate. Moreover, a laminated substrate formed by laminating two or more substrates arbitrarily selected from these can also be used. The term “light transmittance” as used herein means that the transmittance of light having a wavelength of 300 to 450 nm is 70% or more, and more preferably 90% or more.

  When used for thermal nanoimprinting, the substrate does not necessarily have optical transparency. For example, a metal substrate such as a nickel substrate, a titanium substrate, or an aluminum substrate, a semiconductor substrate such as a silicon substrate, or a gallium nitride substrate may be used. it can. The thickness of the template substrate can be set as appropriate within a range of, for example, about 300 μm to 10 mm in consideration of the strength of the substrate, handling suitability, and the like.

(First embodiment)
FIG. 2 is a plan view schematically showing the configuration of the template according to the first embodiment of the present invention, and shows a part of the pattern of the concavo-convex shape for transfer shown in FIG. The concave portion 50 has a concave shape with respect to the reference surface 35, and has a periphery 60 that is a contact side between the concave portion 50 and the reference surface 35. In the present embodiment, the reference surface 35 is a surface that coincides with the height of the substrate main surface 20 of FIG. FIG. 2 shows a line-and-space pattern example in which rectangular concave portions are arranged in parallel at regular intervals as a typical shape of the planar shape of the concave portions. The planar shape of the recess is not limited to a rectangle, and may have various shapes. On the short side of the periphery of the recess, an inclined side wall 70 having an inclined surface of the recess is formed, and a vertical side wall 80 is formed on the long side. In the present invention, the term “perpendicular” may be an angle that allows the sidewall pattern to be formed without any problem during the etch back in the sidewall transfer process, and is preferably 85 to 90 degrees.

  3A is a cross-sectional view taken along one-dot chain line α-α in FIG. Recesses 50 are formed at periodic intervals, and the side walls of the cross section are vertical. FIG. 3B is a cross-sectional view taken along one-dot chain line AA in FIG. The inclined side wall 70 has an inclined shape so that the opening of the recessed portion expands from the recessed portion bottom surface 90 toward the reference surface 35. As described above, the concave portion of the template of the present embodiment has a structure having both the inclined side wall and the vertical side wall on the side wall of the concave portion.

  In the template of this embodiment, when imprinting is performed on the material to be transferred, a transfer convex portion having an inclined shape is formed at the end portion. In the case of optical nanoimprinting, a photocurable film such as an ultraviolet curable resin is used as a transfer material, a template is pressed against the photocurable film, and light is irradiated to transfer the pattern. When a thin film of a transfer material remains on the transfer substrate after imprinting, the remaining film may be removed by ashing with oxygen plasma or the like. Further, if necessary, a slimming process for narrowing the transfer convex portion by plasma treatment or the like may be performed before the deposition of the sidewall material film. Subsequently, the transfer convex portion is used as a core material pattern, and a sidewall material film is deposited so as to cover the transfer convex portion.

  FIG. 4 is a schematic diagram of a cross-section of the pattern edge when a pattern is transferred onto a transfer material by imprinting and a side wall material film is deposited for the side wall transfer process using the template having the recesses of this embodiment. Examples of the substrate to be transferred 110 include a semiconductor wafer substrate, glass for patterned media, or template blanks for producing a copy template. The transfer convex portion 120 is formed on a transfer material such as an organic resist that is a photocurable film by imprinting, and has an inclined shape portion 130 at an end portion. The inclined shape of this end becomes a loop cutting structure. The side wall material film 140 is deposited so as to cover the entire convex portion using the transfer convex portion as a core material pattern. For the deposition of the sidewall material film, a CVD (Chemical Vapor Deposition) method or an ALD (Atomic Layer Deposition) method is used, but the ALD method is particularly preferable.

  Since the ALD method is an atomic layer deposition method using a saturated surface reaction, it is possible to deposit atomic layers one by one. Since the film formation amount by the ALD method is about 0.1 nm to 0.2 nm / cycle, the controllable film formation amount is about the same. For this reason, the deposition of the sidewall material film on the side surface of the resist pattern is more uniform than the case of using a widely used CVD method (thermal CVD, plasma CVD, etc.), and is more uniform on the side surface and upper surface of the resist pattern. It is possible to deposit a side wall material film.

  Furthermore, when an organic resist is used as the core material, the resist pattern shape is not damaged because the film can be formed at a low temperature, and the resist pattern shape is easily maintained, and the sidewall mask shape is good. In a general CVD method, it is difficult to achieve both a low temperature process that does not damage the shape of the organic resist pattern and a uniform coverage on the side and top surfaces of the resist pattern. Coverability is achieved.

  In particular, in the sidewall transfer process, the variation in the thickness of the sidewall material film is directly linked to the variation in the pattern CD (Critical Dimension). The uniformity of the sidewall material film is important. Therefore, when the ALD method is used in the sidewall transfer process, the ALD method is preferable because the sidewall pattern becomes uniform and has a more vertical shape, and the dimensional controllability of a fine pattern is remarkably improved.

  The sidewall material film can be selected as appropriate depending on the etching selection ratio with the substrate to be transferred and the core material pattern, for example, silicon-based silicon oxide, silicon nitride, silicon oxynitride, etc., aluminum-based aluminum-based, hafnium oxide, etc. Examples thereof include titanium-based materials such as hafnium-based and titanium nitride. When the transfer substrate is a metal film, a silicon-based side wall material film is preferable.

  FIG. 5 is a schematic diagram showing the sidewall transfer process, and FIG. 5A is a ZZ cross-section of FIG. The side wall material film 140 covers the transfer convex portion 120 which is a core material pattern. After deposition of the sidewall material film, the upper surface of the core material pattern, the inclined shape portion, and the substrate to be transferred are exposed by etching back that uniformly digs up the entire surface by etching as shown in FIG. Thereby, sidewall patterns 145 are formed on both sides of the core material pattern. As for the etch back amount, when the inclination angle in FIG. 4 is θ and the deposited film thickness D is D / COSθ, the sidewall material film deposited on the inclined shape portion can be removed by etching back, and the loop can be cut.

  After the etch back, the core material pattern is removed as shown in FIG. When the core material pattern is an organic resist, the core material pattern can be easily removed by plasma treatment using an oxygen-based gas. Further, the pattern can be transferred to the transfer substrate by etching using the sidewall pattern 145 formed on the sidewall as a mask.

  When the value of the inclination angle θ is small, the amount of etchback is small and a sufficiently high side wall pattern can be left, but the length of the loop cutting structure becomes long. Further, the inclined portion of the end portion of the side wall pattern becomes long, and it becomes difficult to manufacture the end portion of the transferred substrate with high accuracy. When the inclination angle θ is large, the amount of etch back increases, and the height of the remaining side wall pattern decreases, but the loop cutting structure can be shortened. Considering them, the range of the inclination angle is preferably 20 to 60 degrees, and more preferably 25 to 45 degrees. Further, the inclined shape may be formed from a plurality of inclination angles in the range of 20 degrees to 60 degrees.

Thus, since the template of this embodiment has a structure having both the inclined shape side wall and the vertical shape side wall on the side wall of the recess, a loop cutting structure can be realized by imprint lithography in the side wall transfer process. In the sidewall transfer process using an organic resist as the core material pattern, imprint lithography is used for transfer, and direct transfer is performed by pressing the template against the transfer material. The inclined shape which is a cutting structure can also be stably produced with little variation between patterns.
This makes it possible to stably form the sidewall material film with the loop cut.

  In addition, imprint lithography does not require a complicated exposure apparatus as compared with the photolithography process, and the manufacturing cost can be reduced. In particular, when a replication template is created from a master template using a sidewall transfer process, it is preferable because a replication template having the same shape can be replicated a plurality of times because of excellent stability of the transfer shape.

(First variation of the first embodiment)
Next, a first modification of the first embodiment will be described.
Parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate. FIG. 6 is a cross-sectional view taken along one-dot chain line AA in FIG. 2, and is a diagram showing a first modification of the template of the first embodiment. The plan view of the modified embodiment is the same as FIG. 2, and the α-α cross section of FIG. 2 is also the same as FIG. As shown in FIG. 2, an inclined side wall 70 whose side wall has an inclined surface is formed on the short side around the recess 50, and a vertical side wall 80 is formed on the long side.

  As shown in FIG. 6, the present modified embodiment is different from the first embodiment in that the concave bottom surface side of the side wall has an inclined shape and the edge of the concave opening on the reference surface side has a vertical shape. The structure having the vertical portion 85 at the edge of the concave opening of the inclined side wall 70 can be formed by using a hard mask on the reference surface 35 as an etching mask, as will be described in detail later.

  In the template of this embodiment, when imprinting is performed on the material to be transferred, a transfer convex portion in which the concave portion is inverted is formed. A vertical shape is formed below the end of the transfer convex portion, and an inclined shape is formed on the upper side. Subsequently, the transfer convex portion is used as a core material pattern, and a sidewall material film is deposited so as to cover the transfer convex portion.

  FIG. 7 is a schematic view of a cross section when a pattern is transferred to a transfer material using a template having a concave portion of the present embodiment, and a sidewall material film is deposited for the sidewall transfer process. The transfer protrusion 120 is formed by imprinting an organic resist or the like on the transfer material, and has an inclined shape portion 130 and a vertical shape portion 160 at the end. The vertical shape portion is formed on the bottom surface side of the convex portion, and the inclined shape surface is formed on the top portion side of the convex portion. The side wall material film 140 is deposited so as to cover the entire convex portion using the transfer convex portion as a core material pattern. Thereafter, the upper surface of the core material pattern, the inclined shape portion, the vertical shape portion and the substrate to be transferred are exposed by etch back. The etch back amount can be cut by looping back by D / COS θ + h when the inclination angle in FIG. 7 is θ, the deposited film thickness D, and the height h of the vertical shape portion on the bottom surface side of the convex portion.

  This modified embodiment can shorten the loop cutting structure by having a vertical shape and an inclined shape at the end. Thereby, layout design restrictions can be relaxed. Further, the etch back amount is increased by the height of the vertical portion, and the thickness of the remaining side wall pattern is reduced. However, the transferred substrate may have a structure having a hard mask so that the side wall pattern may be thin.

  Further, as shown in FIG. 6, the template according to this modification has a vertical portion 85 at the edge of the concave opening of the inclined side wall 70. Since the vertical shape portion can be formed by using a hard mask (not shown) on the reference surface 35 as an etching mask, a loop cutting structure including an inclined side wall and a vertical shape portion can be accurately manufactured. The depth of the vertical shape portion 85 can be selected as appropriate depending on the side wall material film, the material of the base substrate, etc., but is preferably 1/3 or less of the depth of the entire recess, and more preferably 1/4 or less. After the deposition of the sidewall material film, etch back is performed to cut the loop in the same manner as described in FIG. 5, and after the sidewall pattern is formed, the sidewall pattern is transferred to the substrate to be transferred in the same manner as in the first embodiment. be able to.

(Second modification of the first embodiment)
Next, a second modification of the first embodiment of the nanoimprint template of the present invention will be described. Parts having the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate. FIG. 8 is a schematic plan view showing the configuration of a template according to the second modification of the present invention, and shows a part of the pattern of the concavo-convex shape for transfer shown in FIG. The concave portion 50 has a concave shape with respect to the reference surface 35, and has a periphery 60 that is a contact side between the concave portion 50 and the reference surface 35. FIG. 8 shows an example of a line-and-space pattern in which rectangular concave portions are arranged in parallel at regular intervals as a representative shape of the planar shape of the concave portions. The planar shape of the recess is not limited to a rectangle, and may be various shapes. A step-shaped side wall 270 having a stepped side wall is formed on the short side around the recess, and a vertical side wall 80 is formed on the long side. 8 is the same as that of FIG. 3A.

  9 is a cross-sectional view taken along one-dot chain line BB in FIG. The step-shaped side wall 270 has a step shape so that the opening of the recess extends from the recess bottom surface 90 toward the reference surface. As for the step shape, one step is formed by the step cross section 200 and the step side surface 210, and FIG. 9 shows an example in which the step is formed in three steps from the bottom surface of the recess to the reference surface. As described above, the concave portion of the template of the second modification has a structure in which both the step-shaped side wall and the vertical side wall have different shapes on the side wall of the concave portion.

  When imprinting is performed on the material to be transferred with the nanoimprint template having the concave portion of the second modified form, a transfer convex portion having a step shape is formed at the end portion. When performing the side wall transfer process, the transfer convex portion is used as a core material pattern, and a side wall material film is deposited so as to cover the transfer convex portion. Thereafter, similar to the process described with reference to FIG. 5, the loop can be cut by etch back. The amount of etch back is determined in accordance with the height of the side surface of the step, the length of the step cross section, and the deposited film of the sidewall material film.

  In the second modification, the shape of the loop removal structure can be adjusted by the number of steps of the step shape. The height of the step side surface and the length of the step cross section in FIG. 9 can be appropriately selected according to various conditions such as the side wall material film and the material of the transfer substrate, but the length of the step cross section 200 depends on the thickness of the deposited film. Longer is preferred.

  As described above, the template of the second modified form has a structure having both the step-shaped side wall and the vertical-shaped side wall on the side wall of the concave portion of the unit, so that a loop cutting structure is realized by imprint lithography in the side wall transfer process. It becomes possible. Further, as shown in FIG. 9, the template of this modification has a step-shaped side wall, and the uppermost step of the recess opening edge is formed by using a hard mask (not shown) on the reference surface 35 as an etching mask. Since it can be formed, a loop cutting structure having a step shape can be manufactured with high accuracy. After the deposition of the sidewall material film, etch back is performed to cut the loop in the same manner as described in FIG. 5, and after the sidewall pattern is formed, the sidewall pattern is transferred to the substrate to be transferred in the same manner as in the first embodiment. be able to.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. Portions that perform the same functions as those in the first embodiment have the same names, and will not be described as appropriate. FIG. 10 is a plan view schematically showing the configuration of the template according to the second embodiment of the present invention, and shows a part of the pattern of the concavo-convex shape for transfer shown in FIG. The convex portion 40 has a convex shape that is formed higher than the reference surface 36, and has a periphery 61 that is a contact side between the convex portion 40 and the reference surface 36. FIG. 10 shows an example of a line-and-space pattern in which rectangular convex portions are arranged in parallel at regular intervals as a representative shape of the planar shape of the convex portions. The planar shape of the convex portion is not limited to a rectangle, and may be various shapes. An inclined side wall 71 whose side wall has an inclined surface is formed on the short side around the protrusion, and a vertical side wall 81 is formed on the long side.

  FIG. 11A is a cross-sectional view taken along one-dot chain line γ-γ in FIG. The convex portions 40 are formed at periodic intervals, and the side wall of the cross section has a vertical shape. FIG. 11B is a cross-sectional view taken along one-dot chain line CC in FIG. The inclined side wall 71 has an inclined shape so that the bottom of the convex portion extends from the upper surface 91 of the convex portion toward the reference surface 36. Thus, the convex part of the template of this embodiment has a structure which has both the inclined shape side wall and the vertical shape side wall on the side wall of the convex part.

  In the template of this embodiment, when imprinting is performed on the transfer material, a transfer recess having an inclined shape is formed at the end. When performing the sidewall transfer process after imprinting the transfer recess, a sidewall material film is deposited so as to cover the transfer recess.

  FIG. 12 is a schematic diagram of a cross section of a pattern end when a pattern having a convex portion according to the present embodiment is used to transfer a pattern onto a transfer material by imprinting and deposit a sidewall material film for the sidewall transfer process. . The transfer substrate 110 may be a semiconductor wafer substrate, glass for patterned media, or template blanks for producing a copy template. The transfer recess 121 is formed on a transfer material such as an organic resist, which is a photocurable film, by imprinting, and has an inclined portion 130 at the end. The inclined shape of this end becomes a loop cutting structure. A sidewall material film 140 is deposited so as to cover the transfer recess. The method for depositing the sidewall material film and the material for the sidewall material film can be the same as those in the first embodiment.

  After the sidewall material film is deposited, the upper surface of the core material pattern, the inclined shape portion, and the substrate to be transferred are exposed by etching back that uniformly digs the entire surface by etching. When the inclination angle in FIG. 12 is θ and the deposited film thickness D is the etch back amount, the sidewall material film deposited on the inclined portion can be removed by etching back by D / COSθ, and the loop can be cut.

  After the etch back, the core material pattern is removed, and the pattern is transferred to the transfer substrate by etching using the side wall pattern formed on the side wall as a mask. If the core material pattern is an organic resist, the core material pattern can be easily removed by plasma treatment using an oxygen-based gas.

  When the value of the inclination angle θ is small, the amount of etchback is small and a sufficiently high side wall pattern can be left, but the length of the loop cutting structure becomes long. Further, the inclined portion of the end portion of the side wall pattern becomes long, and it becomes difficult to manufacture the end portion of the transferred substrate with high accuracy. When the inclination angle θ is large, the amount of etch back increases, and the height of the remaining side wall pattern decreases, but the loop cutting structure can be shortened. Considering them, the range of the inclination angle is preferably 20 to 60 degrees, and more preferably 25 to 45 degrees. The inclined shape may be formed from a plurality of inclination angles in the range of 20 degrees to 60 degrees.

As described above, the template according to the present embodiment has a structure in which both the inclined side wall and the vertical side wall are provided on the side wall of the convex portion. Therefore, the loop cutting structure can be realized by imprint lithography in the side wall transfer process. . In the sidewall transfer process using an organic resist as the core material pattern, imprint lithography is used for transfer, and direct transfer is performed by pressing the template against the transfer material. The inclined shape which is a cutting structure can also be stably produced with little variation between patterns.
This makes it possible to stably form the sidewall material film with the loop cut.

  In addition, imprint lithography does not require a complicated exposure apparatus as compared with the photolithography process, and the manufacturing cost can be reduced. In particular, when a replication template is created from a master template using a sidewall transfer process, it is preferable because a replication template having the same shape can be replicated a plurality of times because of excellent stability of the transfer shape.

  In the modified embodiment of the second embodiment, it is possible to produce a loop removal structure similar to the modified embodiment of the first embodiment by forming the resist in various three-dimensional shapes by electron beam drawing or imprint lithography. .

[Method of manufacturing template for nanoimprint]
(First manufacturing method)
Next, the 1st manufacturing method of the template for nanoimprint of this invention is demonstrated.
The first manufacturing method corresponds to the template manufacturing method of the first embodiment or the first modification of the first embodiment. FIG. 13 is a cross-sectional view of a template showing the first manufacturing method. First, as shown in FIG. 13A, blanks having a hard mask 310 on a substrate 300 are prepared. The hard mask serves as a mask for processing the transfer substrate, and the material is, for example, a metal such as chromium, titanium, tantalum, silicon, or aluminum; a chromium-based compound such as chromium nitride, chromium oxide, or chromium oxynitride; A tantalum compound such as tantalum oxide, tantalum oxynitride, tantalum boride, tantalum oxynitride, tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride or the like may be used alone or in combination of two or more selected arbitrarily. it can. A thickness of about several nm to 50 nm is preferably used.

  Next, as shown in FIG. 13B, the hard mask is patterned to form openings. For the patterning of the hard mask, a conventionally known method may be used. A resin resist is applied on the hard mask, drawing is performed using an electron beam drawing apparatus or the like, and then an opening is formed in the hard mask by development and etching. can do. The shape of the opening of the hard mask can be various shapes around the opening end of the hard mask. Next, as shown in FIG. 13C, a resist is applied, drawing and development are performed, and the resist on the hard mask opening is opened. Furthermore, in this manufacturing method, the side surface of the resist opening is inclined.

  FIG. 14 is a plan view of FIG. 13C, showing the positional relationship between the hard mask opening 401 and the resist opening 402. The one-dot chain line DD cross section of FIG. 14 corresponds to FIG. The hatched portion in FIG. 14 shows the hard mask exposed portion 400 exposed from the resist opening. The dot portion shows the resist 410. A region surrounded by a solid line of the resist region represents a resist inclined portion 420 in which the resist has an inclined shape. White portions in the hard mask openings indicate the substrate exposed portions 430 where the transferred substrate is exposed. A region surrounded by a dotted line of the resist region shows a hard mask opening resist coating portion 440 in which the hard mask is opened and covered with the resist. FIG. 14 shows a line-and-space pattern example in which rectangular hard mask openings are arranged in parallel in the region of the resist opening as a typical pattern shape. There are a plurality of hard mask openings in one resist opening, the short side 450 of the opening end of the hard mask opening is covered with a resist, and the long side 460 is covered with a resist covering the short side. Except for the part where it is, it is exposed from the resist.

  Further, as shown in FIG. 14, the resist inclined portion may be formed in the entire area around the resist opening, or not only in the entire area around the resist opening as shown in FIG. 15, but only on the side where the hard mask opening resist coating portion 440 exists. It may be formed. In FIG. 14, the resist inclined portion includes the end portion of the pattern. However, as shown in FIG. 15, the resist inclined portion does not need to include the end portion of the pattern.

  As a method for forming the resist inclined portion, an inclined shape can be formed by providing a drawing energy with a gradient depending on a drawing position when drawing with an electron beam or a laser after applying a resin resist to a substrate. In addition, when the resist inclined portion is formed all around the resist opening, it can be formed by electron beam drawing or laser drawing. However, the resist opening may be inclined according to the development conditions or the surface treatment of the resist after development. After forming the resist opening having an inclined shape, the substrate is dug by dry etching to form a recess as shown in FIGS.

  In the present manufacturing method, as shown in the plan view of FIG. 14, there are sides where the periphery of the hard mask opening is covered with an inclined resist and sides exposed from the resist. In this way, an inclined side wall and a vertical side wall can be formed. The side wall of the edge of the hard mask opening end covered with the resist having the inclined shape becomes an inclined shape by etching. The tilt angle of the substrate can be adjusted by determining the tilt angle of the resist in consideration of the selectivity between the resist and the etching of the substrate. On the other hand, the side wall of the edge of the hard mask opening end exposed from the resist has a vertical shape because the hard mask serves as an etching mask.

  FIGS. 13 (d) to 13 (f) show the progress of the etching process. By further etching from the state shown in FIG. 13 (d), the hard mask opening end is exposed from the resist as shown in FIG. 13 (e). Can be made. By further etching, the state shown in FIG. In FIG. 13 (f), the etching proceeds in the vertical direction without forming any more inclined shape of the side wall as the hard mask becomes the etching mask during the etching. As a result, the end of the loop cutting structure is determined using the hard mask end as an etching mask, so that the variation in the loop cutting structure can be reduced and it can be stably manufactured with high accuracy.

  Next, the remaining resist (not shown) is peeled off, and then the hard mask is peeled off as shown in FIG. 13G, thereby completing the nanoimprint template. The hard mask may be peeled off entirely, the hard mask may be left on the substrate as it is, or a part of the hard mask that is not necessary may be removed and left. It is also possible to complete etching at the stage of FIG. 13D or FIG. 13E and peel the resist and hard mask to form a final template. Further, by controlling the resist inclination shape by electron beam drawing, the inclination shape can be a curved surface having a plurality of inclination angles. As described above, the nanoimprint template of the present invention can be produced.

(Second manufacturing method)
Next, the 2nd manufacturing method of the template for nanoimprint of this invention is demonstrated.
The second manufacturing method corresponds to the template manufacturing method according to the second modification of the first embodiment. FIG. 16 is a cross-sectional view of a template showing the second manufacturing method. First, blanks having a hard mask on a substrate are prepared, and the hard mask is patterned as shown in FIG. 16A to form openings. The process up to this point is exactly the same as the first manufacturing method.

  Next, as shown in FIG. 16B, a resist is applied, drawing and development are performed, and the resist on the hard mask opening is opened. In the present embodiment, the resist sidewall is not inclined but may be a vertical shape used in normal processing. FIG. 17 is a plan view of FIG. 16B and shows the positional relationship between the hard mask opening 401 and the resist opening 402. The alternate long and short dash line EE corresponds to FIG. The hatched portion in FIG. 17 shows the hard mask exposed portion 400 exposed from the resist opening. The dot portion shows the resist 410. The white area in the hard mask opening indicates the substrate exposed portion 430 where the substrate is exposed. A region surrounded by a dotted line of the resist region shows a hard mask opening resist coating portion 440 in which the hard mask is opened and covered with the resist. FIG. 17 shows a line-and-space pattern example in which rectangular hard mask openings are arranged in parallel in a resist opening region as a typical pattern shape. There are a plurality of hard mask openings in one resist opening, the short side 450 of the opening end of the hard mask opening is covered with a resist, and the long side 460 is covered with a resist covering the short side. Except for the part where it is, it is exposed from the resist.

  After the resist opening is formed, the substrate is dug by dry etching to form a recess as shown in FIGS. In this embodiment, the substrate is not etched to the final depth at once, but is etched in stages. FIG. 16C is a diagram after the first etching. The substrate is dug to a desired depth and etching is temporarily stopped. Next, as shown in FIG. 16D, after the first substrate etching, the resist is subjected to a surface treatment to reduce the thickness of the resist. As the surface treatment method, a method of scraping the surface with oxygen, chlorine or fluorine plasma, or a treatment of exposing to a chemical solution such as ozone water or an alkaline aqueous solution can be used. A plasma etching process capable of continuously processing the substrate without taking it out of the etching chamber is preferable, and a method of exposing to oxygen plasma is more preferable because the side wall of the resist opening can be efficiently retracted. By the surface treatment, the resist is entirely reduced and the side wall of the resist opening is retracted. The amount of retreat may be appropriately selected depending on the desired step shape, but is preferably larger than the thickness of the sidewall material film deposited by the sidewall process.

  Next, the substrate is etched a second time as shown in FIG. Thereby, a step shape is formed on the side wall of the substrate. Etching conditions may be the same as the first etching. Thereafter, the resist is entirely reduced by surface treatment again, and the side wall of the resist opening is retracted. It is preferable that the amount of the receding is the same as the film thickness for depositing the sidewall material film or more than that to expose the entire hard mask opening end from the resist. Alternatively, the entire resist may be peeled off. Next, the substrate is etched a third time under the same conditions as the first and second etching. As a result, the state shown in FIG. Thus, the step shape of a desired number of steps can be obtained by alternately repeating the substrate etching step and the resist surface treatment step.

  In the present manufacturing method, as shown in the plan view of FIG. 17, there are sides where the periphery of the hard mask opening is covered with the resist, and sides exposed from the resist, By alternately repeating the substrate etching step and the resist surface treatment step as in the step shown in FIG. 16, the side wall having a step shape and the side wall having a vertical shape can be formed. The side wall at the edge of the hard mask opening end covered with the resist has a step shape by alternately performing substrate etching and resist surface treatment. On the other hand, the side wall of the edge of the hard mask opening end exposed from the resist has a vertical shape because the hard mask serves as an etching mask.

  In addition, when etching the uppermost step on the main surface side, which is the final step shape forming step as shown in FIG. 16F, the hard mask opening end is also exposed from the resist, and the exposed hard portion is exposed. Etching is preferably performed using the mask opening end as a mask. As a result, the end of the loop cutting structure is determined using the hard mask end as an etching mask, so that the variation in the loop cutting structure can be reduced and it can be stably manufactured with high accuracy.

  Next, the resist is peeled off as shown in (f), and then the hard mask is peeled off as shown in FIG. 16 (g) to complete the nanoimprint template. For the template for nanoimprint, the entire surface of the hard mask may be peeled off, the hard mask may be left on the substrate as it is, or a part of the hard mask that is not necessary may be removed. .

(Modification)
Moreover, FIG. 18 is a figure which shows the case where level | step difference shape is formed in addition to both the rectangular short sides of a recessed part as a modification. FIG. 18A shows an example in which a plurality of L-shaped hard mask openings are formed. By forming the resist opening so as to cover the end of the opening with the resist, a step shape can be formed only at the end of the L-shaped pattern. FIG. 18B shows an example in which a plurality of rectangular hard mask openings are formed, and only the short side on one side of the pattern is covered with a resist. Therefore, a step shape can be formed only on one side of the rectangle. FIG. 18 (c) is an example in which a plurality of rectangular hard mask openings are formed, which are covered with a short-side resist on one side of the pattern and covered with the resist between adjacent patterns. Is different. The edges of adjacent patterns are alternately covered with resist. Therefore, a step shape can be formed alternately with the adjacent pattern at the end of the rectangular pattern. The method of forming the resist openings in FIG. 18 can be used in the same manner in the first manufacturing method, and side walls having a stepped shape or an inclined shape can be formed at the ends of patterns having various shapes.

(Third production method)
Next, the 3rd manufacturing method of the template for nanoimprint of this invention is demonstrated. FIG. 19 shows an example in which the template of the second embodiment is manufactured by the third manufacturing method. First, as shown in FIG. 19A, a substrate having a hard mask 310 is prepared on a substrate 300, and a resist is applied. As the resist, an electron beam sensitive resist or a curable resin for imprint lithography can be used. Next, as shown in FIG. 19B, the resist is patterned by drawing and developing with an electron beam. At the time of drawing, the drawing energy is given a gradient so that the end of the resist has an inclined shape. Alternatively, as another method, the resist can be patterned by performing imprinting using the template according to the first embodiment of the present invention. Next, as shown in FIG. 19C, the hard mask is etched to transfer the resist shape to the hard mask. At this time, the inclined shape of the pattern end is also transferred to the hard mask. Next, as shown in FIG. 19D, the transferred substrate is etched using the hard mask as an etching mask. If the hard mask remains after the desired depth of etching, the hard mask is removed after the substrate is etched to complete the nanoimprint template. The inclination shape can be controlled by the ratio of the etching rate of the resist, the hard mask, and the substrate.

  Moreover, you may produce the template of 1st Embodiment using a 3rd manufacturing method. In that case, the resist of FIG. 19A is formed in accordance with the shape to be dug into the substrate. Although not shown, as an example, a line-and-space space-like opening is formed in the resist. The end of the opening is inclined or stepped, and the other side walls are vertical. Such a shape can be formed by a method of drawing with a gradient in drawing energy by electron beam drawing or by imprint lithography. Thereafter, the hard mask and the substrate are etched in the same manner as in FIGS. 19 (c) and 19 (d). As described above, a template having the cross-sectional structure shown in FIG.

[Example 1]
As a template blank, a hard mask functioning as a substrate etching mask was formed by sputtering on the main surface of a synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches. The hard mask was made of a chromium film having a good etching selectivity with respect to the quartz of the substrate, and the film thickness was 7 nm. Next, an electron beam resist was applied onto the chromium film, drawn with an electron beam, and developed to form a resist pattern. The resist pattern was a line and space pattern in which a plurality of rectangular patterns were arranged at regular intervals. Next, the chromium film as a hard mask was dry-etched with a mixed gas of oxygen and chlorine.

  Thereafter, the resist was peeled off, and a template having a hard mask with a line-and-space pattern in which the hard mask openings became a space pattern and a line pattern between the hard mask openings was prepared. The long side of the hard mask opening was 1000 μm and the short side was 30 nm. The line pattern width between the hard mask openings was 90 nm.

  Next, a positive type electron beam resist was applied to the template, drawn with an electron beam drawing apparatus, and developed. The drawing pattern was set in a rectangular shape so as to include a plurality of hard mask openings. In addition, the drawing energy was drawn with a gradient so that a resist inclined portion was formed around the entire periphery of the resist opening. The resist residual film was made thicker by gradually reducing the writing energy, and the side walls of the resist were inclined. In this example, the resist was applied with a thickness of 200 nm, and the inclination angle of the resist inclined portion was 30 degrees.

  Further, a resist coating portion in which the hard mask is opened and the substrate is directly coated with the resist without using the hard mask is provided at both ends on the short side of the hard mask opening. The coating amount of the resist coating portion was 90 nm on each side. In this embodiment, the edge of the short side of the hard mask opening is included in the resist inclined portion in plan view.

  Next, the substrate exposed from the hard mask opening and the resist opening was dry-etched to a desired depth by using a fluorine-based gas, which is a substrate etching gas, in a dry etching apparatus to form a recess. The etching selectivity between the synthetic quartz glass substrate and the resist was 1 to 1. During etching, the entire periphery of the hard mask opening was exposed from the resist by reducing the thickness of the resist. Thereby, the short side of the hard mask opening was also etched using the hard mask as a mask.

  A concave portion is formed in the shape of the hard mask opening region, and an inclined side wall having a shape extending from the bottom surface of the concave portion toward the main surface is formed on the short side of the hard mask opening, and a vertical shape portion is formed near the main surface of the side wall. Been formed. The depth of the vertical part is 10 nm. The inclination angle of the side wall was 30 degrees, and the length of the orthogonal projection of the inclined side wall toward the concave bottom surface was 90 nm. The depth of the entire recess was 60 nm. Next, the remaining resist was thinned, and the hard mass was peeled off by wet etching with a ceric ammonium nitrate aqueous solution to complete a template for nanoimprinting.

  Furthermore, imprinting was performed using the template of this example. As a substrate to be transferred, template blanks in which a chromium film as a hard mask was formed on synthetic quartz glass were used. A resist for imprinting was dropped onto the blanks by inkjet, the template was pressed, and ultraviolet rays were irradiated from the template side to cure the resist. Thereafter, the substrate to be transferred and the template were separated. A transfer convex portion having the same shape as the concave portion of the template was formed on the transfer substrate.

Next, the transfer convex portion was used as a core material pattern, and a side wall material film to be a side wall pattern was deposited by the ALD method. The material of the sidewall material film was SiO ₂ and the deposited film thickness was 30 nm. Next, the sidewall material film was etched back and dug down uniformly. Etchback was performed by dry etching using a fluorine-based gas. The etch back amount was 60 nm for etch back in consideration of the deposition amount and the tilt angle. After the etch-back, in order to confirm the remaining loop pattern, all the loop patterns were cut when observed using SEM.

  The resist that is the core material pattern was removed by plasma treatment using an oxygen-based gas, and the hard mask was processed by dry etching using a mixed gas of chlorine and oxygen using the sidewall pattern as a mask. Further, the sidewall pattern was removed by wet treatment, and the substrate was processed by dry etching with a fluorine-based gas using the hard mask as a mask. Thereafter, the hard mask was peeled off, and a copy template having a line and space in which the pitch of the template used as a master was halved could be produced.

[Example 2]
As a template blank, a hard mask functioning as a substrate etching mask was formed by sputtering on the main surface of a synthetic quartz glass substrate having a size of 6 inches square and a thickness of 0.25 inches. The hard mask was made of a chromium film having a good etching selectivity with respect to the quartz of the substrate, and the film thickness was 7 nm. Next, an electron beam resist was applied onto the chromium film, drawn with an electron beam, and developed to form a resist pattern. The resist pattern was a line and space pattern in which a plurality of rectangular patterns were arranged at regular intervals. Next, the chromium film as a hard mask was dry-etched with a mixed gas of oxygen and chlorine.

  Thereafter, the resist was peeled off, and a template having a hard mask with a line-and-space pattern in which the hard mask openings became a space pattern and a line pattern between the hard mask openings was prepared. The long side of the hard mask opening was 1000 μm and the short side was 30 nm. The line pattern width between the hard mask openings was 90 nm.

  Next, an electron beam resist is applied to the template, and both ends on the short side of the rectangular hard mask opening are covered with the resist, and other portions of the hard mask opening are exposed from the resist. did. In this example, the resist was applied with a thickness of 300 nm, and the coating amount of the resist coating portion in which the hard mask was opened and the substrate was directly coated with the resist was 90 nm on each side. Next, the substrate exposed from the hard mask opening and the resist opening was etched using a fluorine-based gas, which is a substrate etching gas, in a dry etching apparatus. In the first etching, etching was performed for 20 nm corresponding to 1/3 of the depth of 60 nm of the recess to be finally formed.

  Next, the gas in the chamber was replaced with oxygen, which is a gas for resist surface treatment. By exposing the resist surface to oxygen plasma, the entire resist film was reduced and the resist side wall was retracted. The time of exposure to oxygen plasma and the receding amount of the resist side wall were adjusted with reference to data obtained by testing in advance. In this example, the resist side wall was exposed to oxygen plasma for 45 nm by the time required to recede.

  Next, the gas was replaced with a gas for substrate etching, and the substrate was etched a second time. The substrate was additionally etched by 20 nm, which is 1/3 of the desired depth. The etching gas and etching conditions were the same as the first substrate etching.

  Next, the gas was replaced again with a gas for resist surface treatment. By exposing the resist surface to oxygen plasma, the resist sidewall was retracted. The oxygen plasma treatment was performed for a time sufficient to expose the short side of the hard mask opening end from the resist, and the entire periphery of the hard mask opening was exposed from the resist.

  Next, the substrate etching gas was replaced, and the substrate was etched a third time. The substrate was additionally etched by 20 nm corresponding to 1/3 of the desired depth. The etching gas and etching conditions were the same as the first etching. At this time, the short side of the hard mask opening end was also etched using the hard mask as a mask.

  As described above, a recess having a three-step shape can be formed on the side wall on the short side of the hard mask. The overall depth of the recess was 60 nm, the height of the step side, which is the depth of one step, was 20 nm, and the length of the step cross section in the direction of the short side of the recess was 90 nm. Next, the remaining resist was thinned, and the hard mass was peeled off by wet etching with a ceric ammonium nitrate aqueous solution to complete a template for nanoimprinting.

Furthermore, imprinting was performed using the template of this example.
As a substrate to be transferred, template blanks in which a chromium film as a hard mask was formed on synthetic quartz glass were used. A resist for imprinting was dropped onto the blanks by inkjet, the template was pressed, and ultraviolet rays were irradiated from the template side to cure the resist. Thereafter, the substrate to be transferred and the template were separated. A transfer convex portion having the same shape as the concave portion of the template was formed on the transfer substrate.

Next, the transfer convex portion was used as a core material pattern, and a side wall material film to be a side wall pattern was deposited by the ALD method. The material of the sidewall material film was SiO ₂ and the deposited film thickness was 30 nm. Next, the sidewall material film was etched back and dug down uniformly. Etchback was performed by dry etching using a fluorine-based gas. The etch back was performed for 60 nm in consideration of the amount of the sidewall material film deposited and the height of the step shape. After the etch-back, in order to confirm the remaining loop pattern, all the loop patterns were cut when observed using SEM.

  The resist that is the core material pattern was removed by plasma treatment using an oxygen-based gas, and the hard mask was processed by dry etching using a mixed gas of chlorine and oxygen using the sidewall pattern as a mask. Further, the sidewall pattern was removed by wet treatment, and the substrate was processed by dry etching with a fluorine-based gas using the hard mask as a mask. Thereafter, the hard mask was peeled off, and a copy template having a line and space in which the pitch of the template used as a master was halved could be produced.

Industrial applicability

The template of the present invention is useful for a sidewall transfer process during a manufacturing process of a device such as a semiconductor memory or a replication process of a nanoimprint template. In addition, there is a possibility of application to manufacture by imprinting a three-dimensional structure pattern that requires a complicated shape.
The template manufacturing method of the present invention is useful for manufacturing a template used in the sidewall transfer process. In addition, there is a possibility of application to the manufacture of an imprint template for a three-dimensional structure pattern that requires a complicated shape.

DESCRIPTION OF SYMBOLS 10, 300 ... Board | substrate 11 ... Core material pattern 13 ... Loop structure 20 ... Substrate main surface 30 ... Concavity and convex shape 35, 36 ... Reference plane 40 ... Convex part 50 for transfer ... Recesses 60, 61 ... Periphery 70, 71 ... Inclined shaped side walls 80, 81 ... Vertical shaped side walls 85 ... Vertical shaped part 90 ... Concave bottom surface 91 ... Convex part upper surface 110 ... Transfer substrate 120 ... Transfer convex part 121 ... Transfer concave part 125, 126 ... Core material pattern upper surface 130 ... Inclined shape part 140 ... Side wall material film 145 ... Side wall pattern 200 ... Step cross section 210 ... Step side face 270 ... Step-shaped side wall 310 ... Hard mask 320, 410 ... Resist 400 ... Hard mask exposure part 401 ... Hard mask opening 402 ...・ Regist opening 420 Gist inclined portion 430 ... substrate exposed portion 440 ... hard mask opening resist coating unit 450 ... short sides 460 ... long sides

Claims (10)

  A template for nanoimprinting, comprising a substrate main surface with a concavo-convex shape transfer pattern, wherein the concavo-convex shape has a first side wall having an inclined shape and a second side wall having a vertical shape. Characteristic template for nanoimprint.   2. The nanoimprint template according to claim 1, wherein the first side wall has an inclined shape and a vertical shape.   A template for nanoimprinting, comprising a substrate main surface having a concavo-convex transfer pattern, wherein the concavo-convex shape has a first side wall having a step shape and a second side wall having a vertical shape. Characteristic template for nanoimprint.   The said uneven | corrugated shape is carrying out rectangular shape, it has an inclined shape or a level | step difference shape in a pair of opposing side wall, and the other opposing side wall is a perpendicular | vertical shape. Nanoimprint template.   The nanoimprint template according to any one of claims 1 to 4, wherein the nanoimprint template has optical transparency. A pattern forming method using the nanoimprint template according to claim 5, wherein a step of dropping a photocurable film on a transfer substrate by inkjet,
In a state where the uneven pattern transfer pattern of the nanoimprint template is pressed against the photocurable film, the step of irradiating light through the nanoimprint template to cure the photocurable film;
Separating the nanoimprint template and the substrate to be transferred;
A pattern formed by curing a photocurable film is used as a core material pattern, and a side wall material film is deposited by an ALD method;
A pattern forming method using a template for nanoimprinting, comprising: a step of cutting a loop structure of a sidewall material film by etch back and forming a sidewall pattern on a sidewall of a core material pattern. A method for producing a template for nanoimprinting having a concave-convex shaped transfer pattern having concave portions on a substrate main surface,
A step of preparing a substrate having a hard mask, and a step of processing the hard mask on the substrate, partially opening the hard mask, and forming a hard mask opening around the opening end of the hard mask When,
A resist forming step of providing a resin resist on the substrate;
The periphery of the hard mask opening is exposed from the resist except for the first side where the opening end of the hard mask is covered with the resist and the portion covered with the resist covering the first side. A resist opening forming step of forming a resist opening so as to have a side of
A substrate etching step of etching the substrate exposed from the hard mask opening and the resist opening to form a recess,
The end surface on the hard mask opening of the resist covering the first side has an inclined shape, and the inclined shape resist forms an inclined shape on the side wall of the first side,
A method for producing a template for nanoimprinting, characterized in that a vertical shape is formed on the side wall of the second side by a hard mask opening end exposed from a resist.   The region having the inclined shape of the resist includes a hard mask opening end on the first side in a plan view. In the substrate etching step, the hard mask opening end on the first side is included in the substrate etching process. Etching the substrate using the exposed hard mask opening end as a mask, forming an inclined shape on the bottom side of the recess on the side wall of the first side, and forming a vertical shape on the substrate main surface side 8. The method for producing a template for nanoimprinting according to claim 7, wherein: A method for producing a template for nanoimprinting having a concave-convex shaped transfer pattern having concave portions on a substrate main surface,
A step of preparing a substrate having a hard mask, and a step of processing the hard mask on the substrate, partially opening the hard mask, and forming a hard mask opening around the opening end of the hard mask When,
A resist forming step of providing a resin resist on the substrate;
The periphery of the hard mask opening is exposed from the resist except for the first side where the opening end of the hard mask is covered with the resist and the portion covered with the resist covering the first side. Forming a resist opening so as to have a side of the resist opening; and
Etching the substrate exposed from the hard mask opening and the resist opening to form a recess, and a substrate etching step;
A resist surface treatment step of reducing the resist surface and receding the resist sidewall,
The substrate etching process and the resist surface treatment process are alternately repeated to form a step shape on the side wall of the first side, and a vertical shape is formed on the side wall of the second side by the hard mask opening end exposed from the resist. A method for producing a template for nanoimprinting, comprising:   In the substrate etching step, the substrate etching for forming the uppermost step on the step-shaped substrate main surface side is such that the hard mask opening end on the first side is also exposed from the resist, and the exposed hard mask opening end is Etching as a mask, The manufacturing method of the template for nanoimprints of Claim 9 characterized by the above-mentioned.

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