JP6277643B2 - Manufacturing method of mold for nanoimprint - Google Patents

Description

  The present invention relates to a method for manufacturing a mold for nanoimprint and a mold for nanoimprint manufactured using the method for manufacturing a mold for nanoimprint.

  At present, structures having a fine concavo-convex structure formed on the surface of a substrate are widely used. Examples of the use of the structure in which the fine concavo-convex structure is formed include antireflection, alignment film, water repellency, heat dissipation, and adhesion.

  As a method for forming a fine concavo-convex structure on the substrate surface, for example, after applying a photoresist on the surface of the optical member, this photoresist is exposed and developed to form a resist pattern, and further, the resist pattern is exposed. By corroding the portion, a photolithographic method (see Patent Document 1) for forming a fine concavo-convex structure for each product on the surface of the optical member, or by forming a resist pattern with a submicron pitch by patterning with an electron beam on the surface of the optical member An electron beam lithography method (see Patent Document 2) is proposed in which a fine concavo-convex structure is formed on the surface of the optical member by forming and transferring this resist pattern onto the surface of the optical member by dry etching.

  The photolithographic method is an effective method for manufacturing a large amount of products that require high dimensional accuracy and position accuracy, and is used for manufacturing semiconductor devices and the like. Further, the electron beam lithography method is an effective method for manufacturing a small variety of products requiring high dimensional accuracy and position accuracy, and is used for manufacturing a photomask used for the photolithography method.

  However, the photolithography method and the electron beam lithography method require expensive and special equipment such as an original plate such as a photomask, a high-precision optical device such as an exposure apparatus, and an electron beam device such as a drawing apparatus, and the cost increases. . In addition, it is difficult to form a fine concavo-convex structure in a large area of several tens of centimeters or more due to device limitations. Furthermore, since the electron beam lithography method requires a lot of time for electron beam drawing, the productivity is particularly bad.

  Therefore, these methods are not suitable for manufacturing a product (for example, an antireflection film or the like) that requires a fine concavo-convex structure but does not require high dimensional accuracy and position accuracy. It is also difficult to manufacture these products in a large area.

  In addition to these methods, there is a nanoimprint method as one of the methods for forming a fine relief structure. The nanoimprint method is a method of mechanically transferring a pattern by pressing a mold, which is an original plate on which patterns such as fine grooves and holes, are formed, onto a transfer material (see Non-Patent Document 1). Although the principle of the nanoimprint method is relatively simple, it has attracted attention in recent years because it has been demonstrated that very fine patterns such as several tens to several nm can be transferred.

  However, a mold used for the nanoimprint method is generally manufactured by using a part of a semiconductor device or photomask manufacturing process such as a photolithography method or an electron beam lithography method. Therefore, the nanoimprint method also has a problem that the manufacturing cost of the mold is high. It is also difficult to produce a large area mold.

  Therefore, as a method for manufacturing a nanoimprint mold, a method using a phenomenon in which a fine structure is spontaneously formed has been proposed. For example, there has been proposed a method for producing a liquid crystal alignment film by forming a plurality of columnar objects inclined on the surface of a base material by oblique vapor deposition, and transferring them to a transfer material as a mold ( (See Patent Document 3). According to this method, cost and time can be suppressed and productivity is improved as compared with the case where a mold is manufactured by a photolithography method or an electron beam lithography method.

  However, the method described in Patent Document 3 does not mention the detailed shape of the fine uneven structure of the manufactured nanoimprint mold, and the controllability of the shape is unclear. In addition, since a flat substrate is used, there is a problem that it is difficult to form a fine uneven structure uniformly over a large area.

  As a method for transferring a fine concavo-convex structure formed by a photolithographic method, an electron beam lithography method, or the method of Patent Document 3 to a large area, the fine concavo-convex structure formed in a small area is duplicated on a plurality of films, A method is conceivable in which these are joined together and attached to a roll to form a roll-shaped mold. However, even when using a roll-shaped mold in which the replicated films are joined together, defects occur in the fine concavo-convex structure at the part where the films are joined together. It is difficult to manufacture.

Japanese Patent Laid-Open No. 50-70040 JP 2001-272505 A JP 2007-47250 A

Applied Physics Letters, vol. 67, p. 3314, 1995

The prior art described above has the following three problems.
The first problem is that expensive and special equipment such as a photolithography method and an electron beam lithography method is required.
The second problem is that the shape of the fine uneven structure (for example, the period of the fine uneven structure) cannot be easily controlled.
The third problem is that the fine concavo-convex structure cannot be uniformly transferred over a large area.

  The objective of this invention is providing the mold for nanoimprint manufactured using the manufacturing method of the mold for nanoimprint which can solve the said three subject, and the manufacturing method of the mold for nanoimprint.

In order to achieve the above object, one embodiment of the present invention relates to a method for producing a mold for nanoimprinting, in which a roll-shaped substrate is disposed in one region in a sputtering chamber partitioned by a shielding plate, and the other The process of disposing the sputter target in the region of the above, and rotating the roll-shaped base material, applying a predetermined power to the electrode under the sputter target and performing plasma discharge , randomly on the surface of the roll-shaped base material A step of forming an inorganic layer having a plurality of protrusions formed in an array by a sputtering method , and the shielding plate has openings having a uniform width in a direction parallel to the length direction of the roll-shaped substrate. In the inorganic layer forming step, the sputter particles flying from the sputter target pass through the opening of the shielding plate and reach the surface of the roll-shaped base material, so that the surface of the roll-shaped base material To form a projection for, and you characterized in that joint without forming a protrusion with respect to the roll-shaped substrate.

The free machine layer, can be used chromium or chromium compound (e.g., chromium nitride, chromium oxide, etc.). Further, in this method for producing a mold for nanoimprint, it is possible to control the period in which the protrusions are arranged by changing the sputtering conditions.

Further, the protrusions can be formed to be inclined at an arbitrary angle with respect to the surface of the roll-shaped substrate.

  According to the method for producing a mold for nanoimprinting of the present invention, a nanoimprinting mold having a fine concavo-convex structure can be easily produced without using an expensive and special equipment method such as a photolithography method or an electron beam lithography method. it can.

  Moreover, according to the method for producing a mold for nanoimprinting of the present invention, the shape of the fine uneven structure can be easily controlled, and therefore the shape of the fine uneven structure can be appropriately selected according to the application.

  Moreover, according to the method for producing a mold for nanoimprinting of the present invention, a fine concavo-convex structure can be formed on a roll-shaped substrate without joints. Therefore, a large-area product can be easily manufactured by transferring this.

  In particular, when the oblique deposition method is used, it is difficult to form a fine concavo-convex structure uniformly in a large area. However, according to the method for producing a mold for nanoimprinting of the present invention, the fine concavo-convex structure is formed into a roll-shaped base. It can be uniformly formed by inclining at a predetermined angle with respect to the surface of the material. Therefore, by transferring this, a product such as an alignment film that requires an inclined fine concavo-convex structure can be manufactured in a large area.

Sectional drawing which illustrates typically each process of the manufacturing method of the mold for nanoimprint which concerns on one Embodiment of this invention. The SEM (Scanning Electron Microscope) image which looked down at the section of the inorganic layer which has a plurality of projections in the manufacturing method of the present invention Sectional drawing which illustrates typically the protrusion formed in the upper surface of the inorganic layer in the manufacturing method of this invention The figure which illustrates typically the process of forming the inorganic layer which has an unevenness | corrugation in a roll-shaped base material.

  Hereinafter, a method for producing a mold for nanoimprinting and a mold for nanoimprinting according to an embodiment of the present invention will be described in detail with reference to FIG.

  First, as shown to Fig.1 (a), the base material 10 is prepared, the inorganic layer 11 which has the some protrusion 12 is formed on the surface of the base material 10, and the mold 13 for nanoimprint is obtained.

  The material of the substrate 10 is not particularly limited as long as conditions such as mechanical strength and surface roughness necessary for use as a mold substrate are satisfied. For example, quartz glass, silicon, nickel, chromium and the like can be mentioned. In the later step, when transferring the fine concavo-convex structure of the nanoimprint mold 13, quartz glass may be used when the mold is required to be transparent for reasons such as using a UV nanoimprint method. However, other materials may be used if there is no problem in the implementation of this embodiment.

  The material of the inorganic layer 11 can be appropriately selected according to the formation method of the inorganic layer 11 and the like. For example, when the inorganic layer 11 is formed by a sputtering method, chromium or a chromium compound (for example, chromium nitride, chromium oxide, etc.) is preferable. When the nanoimprint mold 13 is required to be transparent, a transparent material such as silicon dioxide may be used. However, other materials may be used if there is no problem in the implementation of this embodiment.

  In consideration of forming the inorganic layer 11 so that a plurality of protrusions 12 are formed in the inorganic layer 11, a sputtering method is preferable. Of the sputtering methods, the reactive sputtering method is particularly preferable. According to the reactive sputtering method, the discharge power, the sputtering gas pressure, the ratio of the reactive gas flow rate to the total sputtering gas flow rate, the distance between the sputtering target and the substrate 10 (hereinafter referred to as the TS position), the film formation. This is because the shape of the inorganic layer 11 (also referred to as the shape of the protrusions 12) can be easily controlled by changing the time as a parameter. However, other formation methods may be used as long as there is no problem in implementation of this embodiment.

  Here, the protrusion 12 will be described. The protrusion 12 refers to a portion of the inorganic layer 11 where irregularities are formed on the upper surface of the inorganic layer 11. For example, as shown in FIG. 2 (a) and FIG. 3 (a), in addition to a columnar material in which an inorganic material has grown directly in a columnar shape on a substrate, as shown in FIG. 2 (c) and FIG. 3 (b) The protrusion may be formed by growing an inorganic layer on the substrate and locally growing an inorganic material on the inorganic layer.

In addition, the period of the concavo-convex structure to be described later is a value obtained by observing a cross-section of the columnar object or the inorganic layer 11 on which the protrusion is formed with an SEM and measuring the width of the protrusion 12 seen in the cross-section. Here, the width w of the protrusion 12 will be described with reference to FIGS. 3 (a) and 3 (b). The width w of the protrusion 12 is the width of the groove between the bottom of the groove between the protrusion contacting with the left side and the protrusion contacting with the right side when attention is paid to any protrusion 12 in the sectional view. Indicates the horizontal distance to the bottom. Since the concavo-convex structure is formed by arranging the protrusions 12, the width w of the protrusions 12 can be considered as the period of the concavo-convex structure.
Since the protrusions 12 are formed at random, the shape of each protrusion 12 is different. Therefore, the period of the concavo-convex structure was calculated from the average value of the width w of five protrusions 12 extracted at random from the cross-sectional SEM image.

Further, the depth of the concavo-convex structure is a value obtained by observing the cross section of the inorganic layer 11 with an SEM and measuring the height of the protrusion 12 seen in the cross section. Here, the height of the protrusion 12 will be described with reference to FIGS. 3 (a) and 3 (b). The height d of the protrusion 12 is the depth to the bottom of the groove between the protrusion 12 in contact with the left side with respect to the tip of the protrusion 12 when an arbitrary protrusion 12 is noted in the cross-sectional view. This is a value obtained by measuring the depth d2 to the bottom of the groove between d1 and the protrusion contacting on the right side and calculating the average value of the depth d1 and the depth d2.
Since the protrusions 12 are formed at random, the shape of each protrusion 12 is different. Therefore, the depth of the concavo-convex structure was calculated from the average value of the heights d obtained by randomly extracting five protrusions 12 from the cross-sectional SEM image.

For example, in the case of sputtering chromium using Ar as the sputtering gas and introducing nitrogen as the reactive gas, the discharge power is 600 W, the sputtering gas pressure is 0.3 Pa, the ratio of the reactive gas flow rate is 10%, T When the -S position is 250 mm and the film formation time is 10 minutes, the inorganic layer 11 having the surface form shown in FIG. In this case, the period of the concavo-convex structure (which may also be referred to as the width of the protrusion 12) is 27 nm, and the depth of the concavo-convex structure is 12 nm.
In the above case, for example, assuming that the discharge power is 800 W, the sputtering gas pressure is 0.2 Pa, the ratio of the reactive gas flow rate is 7%, the TS position is 250 mm, and the film formation time is 10 minutes, FIG. The inorganic layer 11 having the surface morphology shown in b) is obtained. In this case, the period of the concavo-convex structure is 61 nm, and the depth of the concavo-convex structure is 35 nm.
In the above case, for example, assuming that the discharge power is 800 W, the sputtering gas pressure is 0.2 Pa, the ratio of the reactive gas flow rate is 7%, the TS position is 250 mm, and the film formation time is 40 minutes, FIG. The inorganic layer 11 having the surface form shown in c) is obtained. In this case, the period of the concavo-convex structure is 221 nm, and the depth of the concavo-convex structure is 60 nm.

  As described above, according to the experiment by the inventors, the shape of the inorganic layer 11 could be easily controlled by controlling the parameters described above. For this reason, according to the method for producing a mold for nanoimprinting of the present invention, the shape of the fine concavo-convex structure can be appropriately selected according to the application.

  Further, the shape of the substrate 10 is not limited to a flat plate shape, and may be a roll shape. Below, the method to form the inorganic layer 11 seamlessly on a roll-shaped base material using sputtering method is demonstrated with reference to FIG.

  As shown in FIG. 4A, a base material 30 is prepared in a sputtering chamber, a partial shielding plate 51 is installed between the base material 30 and the sputter target 50, and the base material 30 is rotated. A predetermined power is applied to the electrode under the sputtering target 50 to cause plasma discharge, and the inorganic layer 31 is formed on the surface of the substrate 30.

  Here, the partial shielding plate 51 refers to a shielding plate having openings of uniform width in the length direction of the cylinder. Sputtered particles flying from the sputter target 50 reach the substrate 30 only at locations corresponding to partial openings of the shielding plate 51.

  As shown in FIG. 4A, when the openings of the partial shielding plate 51 are arranged in parallel with the sputter target 50, the sputtered particles reach the surface of the substrate 30 almost perpendicularly. Therefore, as shown in FIG. 4B, a roll-shaped nanoimprint mold 33 having an inorganic layer 31 in which protrusions grow perpendicularly to the surface of the substrate 30 is obtained.

  On the other hand, as shown in FIG. 4C, when the relative positional relationship between the sputter target 50 and the opening of the partial shielding plate 51 is changed, the sputtered particles are placed on the surface of the substrate 40. It reaches from a predetermined angle α. Therefore, as shown in FIG. 4D, a roll-shaped nanoimprint mold 43 having an inorganic layer 41 in which protrusions are grown at an angle α with respect to the surface of the substrate 40 is obtained.

  In FIG. 4C, the arrangement of the partial shielding plate 51 is changed. However, the same effect can be obtained when the arrangement of the partial shielding plate 51 is fixed and the arrangement of the sputter target 50 is changed. Thus, the protrusions can be grown with an inclination relative to the surface of the substrate 40.

  When the method for forming an inorganic layer on the roll-shaped substrate described with reference to FIG. 4 is used, the inorganic layer grows sequentially over the entire surface of the roll, so that a joint is generated in the fine concavo-convex structure. Absent. Therefore, if this is used as a mold and a fine uneven structure is transferred, a product with a large area can be produced without causing defects such as joints. In particular, when the columnar material is grown on the flat plate by oblique vapor deposition, there is a problem that the film thickness and the shape of the columnar material become non-uniform, but according to the method of the present invention, the protrusion is inclined. Even when grown, the film thickness and the shape of the protrusions can be made uniform over the entire roll-shaped mold.

  Next, a process of transferring the fine uneven structure of the manufactured nanoimprint mold to a transfer material will be described. As shown in FIG. 1B, a substrate 20 is prepared, a transfer material 21 is formed on the substrate 20, and the fine uneven structure of the nanoimprint mold 13 is transferred to the transfer material 21. The fine concavo-convex structure formed body 22 shown in 1 (c) is obtained.

  The method for transferring the fine uneven structure of the nanoimprint mold 13 to the transfer material 21 is not particularly limited as long as the fine uneven structure of the inorganic layer 11 is transferred. For example, UV nanoimprint method, thermal nanoimprint method and the like can be mentioned. However, other transfer methods may be used if there is no problem in the implementation of this embodiment.

  The material of the base material 20 can be appropriately selected according to the transfer method used. For example, when the UV nanoimprint method is used, quartz glass, silicon, polyethylene terephthalate (hereinafter referred to as PET), and the like can be given. In addition, for example, when the thermal nanoimprint method is used, quartz glass, silicon and the like are preferable. When a polymer film such as PET is used, the temperature at which the substrate 20 is heated during transfer needs to be within a range in which the physical properties of the substrate 20 do not change. However, other materials may be used if there is no problem in the implementation of this embodiment.

  The material of the transfer material 21 can be appropriately selected according to the transfer method used. For example, when a UV nanoimprint method is used, a photocurable resin may be used. For example, when using the thermal nanoimprint method, a thermoplastic resin may be used. However, other materials may be used if there is no problem in the implementation of this embodiment.

  The method for forming the transfer material 21 can be appropriately selected according to the viscosity of the resin used. Examples thereof include a bar coating method, a spin coating method, and a die coating method. However, other formation methods may be used as long as there is no problem in implementation of this embodiment.

  The obtained fine concavo-convex structure formed body 22 can be used for applications such as antireflection, alignment film, water repellency, heat dissipation, and adhesion.

(Example)
Examples of the nanoimprint mold according to the embodiment of the present invention will be described below.
First, a base material 10 made of a silicon wafer was prepared, and an inorganic layer 11 made of chromium nitride having a thickness of 100 nm was formed on the surface of the base material 10 by a reactive sputtering method to obtain a nanoimprint mold 13 (FIG. 1 ( a)).

  The chromium target used for this sputtering has a purity of 99.995%. The TS position was 250 mm. 90 sccm of argon and 10 sccm of nitrogen were introduced into the sputtering chamber, the pressure in the sputtering chamber was set to 0.3 Pa, and 600 W was applied to the electrode under the target by a DC power source to cause plasma discharge.

  FIG. 2A shows a surface SEM image of the inorganic layer 11 made of chromium nitride. The inorganic layer 11 has a plurality of protrusions 12 on the upper surface, and the period of the formed uneven structure was 27 nm.

  Next, a substrate 20 made of a PET film was prepared, and a photocurable resin was applied to the surface of the substrate 20 with a bar coater to form a transfer material 21 having a film thickness of 5 μm (FIG. 1B). .

  Next, the nanoimprint mold 13 is pressed against the material to be transferred 21 formed on the substrate 20 so that the surface of the inorganic layer 11 is in contact with the UV light from the substrate 20 side. The transfer material 21 was cured, and the nanoimprint mold 13 was released to obtain a fine concavo-convex structure formed body 22 (FIG. 1C).

  In this example, the nanoimprint mold 13 having the fine concavo-convex structure shown in FIG. 2B or FIG. 2C is obtained by changing the sputtering conditions when the inorganic layer 11 is formed by the reactive sputtering method. Is obtained.

  The method for producing a nanoimprint mold and the nanoimprint mold of the present invention are expected to be used in a wide range of fields in which it is required to form a fine relief structure. For example, it is expected to be used for applications such as antireflection, alignment film, water repellency, heat dissipation, and adhesion.

10, 20, 30, 40 Base material 11, 31, 41 Inorganic layer 12 Protrusion 13, 33, 43 Nanoimprint mold 21 Transfer material 22 Fine concavo-convex structure formed body 50 Sputter target 51 Partial shielding plate

Claims (4)

A method for producing a mold for nanoimprinting,
Arranging a roll-shaped substrate in one region in the sputtering chamber partitioned by a shielding plate, and disposing a sputtering target in the other region;
While rotating the roll-shaped substrate, a predetermined electric power is applied to the electrode under the sputter target to perform plasma discharge, and a plurality of randomly formed surfaces are formed on the surface of the roll-shaped substrate. A step of forming an inorganic layer having a protrusion by a sputtering method ,
The shielding plate has an opening having a uniform width in a direction parallel to the length direction of the roll-shaped substrate,
In the inorganic layer forming step, the sputtered particles flying from the sputter target pass through the opening of the shielding plate and reach the surface of the roll-shaped base material, so that the surface of the roll-shaped base material is The method for producing a mold for nanoimprint , wherein the projection is formed and the projection is formed seamlessly with respect to the roll-shaped substrate . The method for producing a mold for nanoimprint according to claim 1, wherein the inorganic layer is made of chromium or a chromium compound. The method for producing a mold for nanoimprinting according to claim 1 or 2 , wherein a period in which the protrusions are arranged is controlled by changing sputtering conditions. The production of the nanoimprint mold according to any one of claims 1 to 3, wherein the protrusion is formed to be inclined at an arbitrary angle with respect to the surface of the roll-shaped substrate. Method.