CN112203821B

CN112203821B - Pattern master, method for manufacturing pattern master, method for manufacturing mold, and method for manufacturing substrate

Info

Publication number: CN112203821B
Application number: CN201980035676.5A
Authority: CN
Inventors: 梅泽朋一
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2018-05-30
Filing date: 2019-05-17
Publication date: 2022-11-04
Anticipated expiration: 2039-05-17
Also published as: CN112203821A; JPWO2019230460A1; TW202012139A; CN115503159A; WO2019230460A1; JP6956869B2

Abstract

A pattern master having a fine uneven pattern on a surface thereof, a method for manufacturing the pattern master, a method for manufacturing a mold, and a method for manufacturing a base having an uneven structure on a surface thereof, wherein the pattern master comprises a base and an uneven structure layer provided on one surface of the base, at least one surface of the base is made of a material having an etching stop function, the base is exposed to a bottom of at least a part of recesses in the uneven structure layer, and a variation in a bottom point position of each recess of the uneven pattern in a direction perpendicular to the one surface in the uneven pattern is 20nm or less.

Description

Pattern master, method for manufacturing pattern master, method for manufacturing mold, and method for manufacturing base

Technical Field

The present invention relates to a pattern master having a fine uneven pattern on a surface thereof, a method for manufacturing the pattern master, a method for manufacturing a mold using the pattern master, and a method for manufacturing a substrate having an uneven structure on a surface thereof.

Background

In a transparent substrate such as a lens or cover glass made of glass or plastic, an antireflection structure or an antireflection film may be provided on a light incident surface in order to reduce loss of transmitted light due to surface reflection. For example, as an antireflection structure against visible light, a fine uneven structure having a pitch shorter than the wavelength of visible light, a so-called moth-eye structure, is known.

As a method for forming a moth-eye structure, a pattern transfer technique by a nanoimprint method is attracting attention from the viewpoint of throughput (see japanese patent application laid-open No. 2015-029118 (hereinafter, patent document 1)). Nanoimprinting is a technique in which a mold having an uneven pattern is pressed against a resist applied to a workpiece, and the resist is mechanically deformed or fluidized to precisely transfer a fine pattern to a resist film. After the pattern transfer, for example, the object is etched using the resist to which the pattern is transferred as a mask, whereby an uneven structure can be formed on the surface of the object. In addition, a mold having a concave-convex pattern is also generally referred to as a mold, a stamper, or a template. Hereinafter, the mold having the uneven pattern for imprinting is referred to as a mold.

As a mold used in the nanoimprint method, for example, a mold having an uneven structure including an anodized porous alumina layer on a substrate is known (international publication No. 2010/087139 (hereinafter, patent document 2) and japanese patent application laid-open No. 2012-137534 (hereinafter, patent document 3)).

Further, japanese patent application laid-open No. 2007-268831 (hereinafter, patent document 4) discloses a method of manufacturing a mold, in which a resist layer is formed on a substrate, exposure and pattern formation by development are performed on the resist layer, and the patterned resist layer is etched using as a mask to manufacture a mold in which a concave-convex pattern is formed on a surface of the substrate. Patent document 4 discloses a method of manufacturing a mold, in which a laminate of the same material having different surface orientations is used as a substrate, and a mold having an uneven pattern with a constant uneven depth is manufactured by using an etching rate that varies depending on the surface orientation.

In the nanoimprint method, the same mold can be used repeatedly many times, but the mold deteriorates with the number of times of repetition. Therefore, for example, in the field of manufacturing optical elements, surface processing, and the like, it is necessary to duplicate a mold having the same pattern to prepare a plurality of molds in advance. In order to copy the mold, a master mold (pattern master (original disc)) having an inverse concave-convex structure with respect to the concave-convex structure of the mold is used.

Jp 2013-185188 a (hereinafter, patent document 5) and jp 2015-059977 a (hereinafter, patent document 6) disclose a method of forming a fine uneven structure layer made of gibbsite on a substrate surface and etching the substrate surface using the uneven structure layer as a mask. In particular, patent document 5 describes a method for manufacturing a pattern master used for manufacturing a mold.

Disclosure of Invention

Technical problem to be solved by the invention

In the production of the molds of

patent documents

2 and 3, in order to form the moth-eye structure, it is necessary to repeat anodization and etching, which takes time. In the production of the mold of patent document 4, it takes time to perform the steps of exposing and developing the resist. In the manufacture of molds, an increase in throughput is desired.

On the other hand, as in patent document 5, when a pattern master is produced using an uneven structure layer made of gibbsite as an etching mask and an imprint mold is produced using the pattern master, a mold can be produced with a higher throughput than in the past.

However, it is known that: when imprinting is performed using a mold manufactured using a pattern master manufactured by the method described in patent document 5, there may be a problem that the height of the irregularities of the irregularity pattern formed on the surface of the workpiece is extremely small, or a desired irregularity pattern cannot be formed. Further, the inventors have found, through intensive studies: since the variation in the height position of the peak of the convex portion in the concave-convex pattern of the mold is large, a large variation occurs in the thickness of the residual film of the resist at the time of imprinting, which is a cause of this problem. Further, it was found that the variation in the height position of the apex of the convex portion of the mold was the variation in the height position of the base of the concave portion in the concave-convex pattern of the pattern master.

The present invention has been accomplished in view of the above circumstances. The purpose of the present invention is to provide a pattern master in which variations in the height of the bottom points of the recesses of an uneven pattern are suppressed, a method for manufacturing the pattern master, a method for manufacturing a mold using the pattern master, and a method for manufacturing a substrate having an uneven structure on the surface.

Means for solving the technical problem

The following means are included in specific means for solving the above-described problems.

< 1 > a pattern master having a fine uneven pattern on a surface thereof, the pattern master comprising a substrate and an uneven structure layer provided on one surface of the substrate and including a plurality of projections and a plurality of recesses along the uneven pattern, at least the one surface of the substrate being made of a material having an etching stop function, the substrate being exposed to bottoms of at least some of the recesses of the uneven structure layer, and a variation in bottom point position of each recess of the uneven pattern in a direction perpendicular to the one surface being 20nm or less in the uneven pattern.

< 2 > the pattern master according to < 1 >, wherein the uneven pattern is uneven and has an average period of 400nm or less.

< 3 > such as < 1 > or < 2 >, wherein in the uneven pattern, the variation in the position of the apex of each convex portion in the direction perpendicular to the one surface exceeds 5nm.

The pattern master of any one of < 4 > and < 1 > to < 3 >, wherein an interdiffusion layer in which a material constituting the concavo-convex structure layer and a material constituting the one surface of the base are mixed with each other is formed in an interface region between the concavo-convex structure layer and the base.

< 5 > such as < 1 > to < 4 >, wherein the one surface of the substrate is made of silicon oxide.

< 6 > the pattern master as defined in any one of < 1 > to < 4 >, wherein said one surface of said substrate is made of metal.

The pattern master of any one of < 7 > and < 1 > to < 6 >, wherein the concavo-convex structure layer is a layer containing silicon as a main component.

The pattern master of any one of < 8 > and < 1 > to < 4 >, wherein the concavo-convex structure layer is a layer containing silicon as a main component, and the one surface of the base is a layer containing nickel as a main component.

< 9 > such as < 8 >, wherein a nickel silicide layer is formed in an interface region between the concavo-convex structure layer and the substrate.

The pattern master of any one of < 10 > such as < 7 > to < 9 >, wherein the concavo-convex structure layer is made of polycrystalline or amorphous silicon.

The pattern master of < 11 > as defined in any of < 1 > to < 10 >, wherein the substrate is composed of a laminate comprising: a 1 st layer comprising the one surface; and a 2 nd layer made of a different material from the 1 st layer.

< 12 > a method for manufacturing a pattern master, comprising preparing a laminate having a layer to be processed and a thin film containing aluminum in this order on one surface of a substrate, wherein at least the one surface of the substrate is made of a material having an etching stop function, subjecting the thin film containing aluminum to a warm water treatment to form a 1 st uneven structure layer made of an alumina hydrate, etching the 1 st uneven structure layer and the layer to be processed from the 1 st uneven structure layer side until the 1 st uneven structure layer is removed, and wherein the one surface of the substrate is exposed to at least a part of a recessed portion formed in the layer to be processed, and processing the layer to be processed into a 2 nd uneven structure layer including a plurality of projecting portions and a plurality of recessed portions.

< 13 > the method of manufacturing a pattern master as < 12 >, wherein in the etching step, when the etching rate of the 1 st uneven structure layer is Ra, the etching rate of the layer to be processed is Rw, and the etching rate of the base is Rs,

and etching the layer to be processed after exposing the layer to be processed to the recessed portion of the 1 st uneven structure layer under the condition of Rw > Ra > Rs.

< 14 > such as < 12 > or < 13 > wherein at least one of the surfaces of the substrate is made of silicon oxide or metal.

The method of manufacturing a pattern master of < 15 > such as < 12 > to < 14 >, wherein the layer to be processed is a layer containing silicon as a main component.

The method of manufacturing a pattern master of < 16 > such as < 12 > to < 15 >, wherein in the etching, an etching gas containing halogen atoms is used.

< 17 > the method for manufacturing a pattern master as < 16 >, wherein the halogen atom is a fluorine atom.

The method of manufacturing a pattern master of < 18 > such as < 12 > to < 17 >, wherein the thin film containing aluminum has a film thickness of 2nm to 20nm.

The method of manufacturing a pattern master of < 19 > such as < 12 > to < 18 >, wherein the etching step is followed by a heat treatment.

< 20 > a method for producing a mold, wherein the pattern master of any one of < 1 > to < 11 > is used,

and manufacturing a mold having a transferred concave-convex pattern of the pattern master on a surface thereof.

< 21 > and < 20 > are the methods for producing a mold, wherein a resin composition layer is formed along the uneven pattern on the surface of the pattern master, the resin composition layer is cured to form a resin layer having a transferred uneven pattern of the uneven pattern, and the resin layer is peeled from the pattern master to obtain a flexible mold having the transferred uneven pattern on the surface.

< 22 > a method for producing a substrate having an uneven structure on a surface thereof, which comprises using the pattern master described in any one of < 1 > to < 11 > to produce a mold having a 1 st transfer uneven pattern having the uneven pattern transferred thereto on a surface thereof, applying a resist to one surface of a substrate to be processed, pressing the 1 st transfer uneven pattern of the mold against the resist to thereby transfer the 1 st transfer uneven pattern to the resist to form a 2 nd transfer uneven pattern, curing the resist having the 2 nd transfer uneven pattern formed thereon to thereby form a 2 nd resin layer having the 2 nd transfer uneven pattern, and etching the 2 nd resin layer and the substrate to be processed from the 2 nd resin layer side using the 2 nd resin layer having the 2 nd transfer uneven pattern as a mask to thereby form the uneven pattern on the surface of the substrate to be processed.

Effects of the invention

According to an embodiment of the present invention, it is possible to provide a pattern master in which the positional deviation of the bottom of the concave portion of the uneven pattern is suppressed.

Drawings

Fig. 1 is a schematic cross-sectional view of a pattern master according to embodiment 1 of the present invention.

Fig. 2 is an enlarged view of a part of the pattern master shown in fig. 1.

Fig. 3 is a scanning electron microscope image obtained by imaging the concave-convex pattern of the pattern master according to the embodiment of the present invention from a direction perpendicular to one surface of the substrate.

Fig. 4 is a scanning electron microscope image obtained by imaging the concave-convex pattern of the pattern master of another embodiment of the present invention from a direction perpendicular to one surface of the substrate.

Fig. 5 is a scanning electron microscope image of the concave-convex pattern of the pattern master of still another embodiment of the present invention taken from a direction perpendicular to one surface of the base.

Fig. 6 is a view schematically showing an interdiffusion layer formed between a relief structure layer and a base in a pattern master according to an embodiment.

Fig. 7 is a schematic cross-sectional view of a pattern master according to embodiment 2 of the present invention.

Fig. 8 is a diagram showing a process for manufacturing a pattern master according to embodiment 2.

Fig. 9 is a diagram showing a manufacturing process of a flexible mold according to an embodiment of the present invention.

Fig. 10 is a view showing a manufacturing process of a substrate having an uneven structure on a surface thereof.

Fig. 11 is a scanning electron microscope image obtained by photographing the surface of the pattern master of the example.

Fig. 12 is a scanning electron microscope image obtained by taking a cross section of the pattern master of the example.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the scale of each component in the drawings is appropriately different from the actual scale for easy visual recognition.

"Pattern original disc"

A pattern master according to embodiment 1 of the present invention will be described. Fig. 1 is a schematic cross-sectional view of a pattern master 1 according to embodiment 1.

The pattern master 1 has a fine uneven pattern 2 on the surface. The pattern master 1 includes a substrate 10 and a concavo-convex structure layer 20, and the concavo-convex structure layer 20 is provided on one surface 10a of the substrate 10 and includes a plurality of convex portions 22a and a plurality of concave portions 22b along the concavo-convex pattern 2. At least one surface 10a of the base 10 is made of a material different from the concavo-convex structure layer 20, and particularly, one surface 10a of the base 10 is made of a material having an etching stop function. Here, the material having the etching stop function means a material having an etching rate lower than that of the concave-convex structure layer 20 with respect to an etching gas when the concave-convex structure layer 20 is formed by etching. In particular, a material having an etching rate lower than that of the concave-convex structure layer 20 with respect to an etching gas containing at least one of a rare gas, an oxygen gas, a fluorine-based gas, and a chlorine-based gas is preferable.

The uneven pattern 2 is mainly composed of a plurality of convex portions 22a and a plurality of concave portions 22b of the uneven structure layer 20. That is, the uneven structure layer 20 includes convex portions 22a and concave portions 22b along the uneven pattern 2. Most of the convex portions 2a and the concave portions 2b of the concave-convex pattern 2 coincide with the convex portions 22a and the concave portions 22b of the concave-convex structure layer 20.

Fig. 2 is a partially enlarged view of the pattern master 1 shown in fig. 1. The substrate 10 is exposed to the bottom of at least a part of the recesses 22b in the recess 22b of the concavo-convex structure layer 20. In this case, the substrate 10 may have a configuration in which the one surface 10a of the substrate 10 is exposed to the bottom of the concave portion 22b of the uneven structure layer 20, or a configuration in which the substrate 10 is exposed to the bottom of the concave portion 22b of the uneven structure layer 20 and the concave portion 10b is also formed in a part of the substrate 10. In these cases, the concave portions 2b of the concave-convex pattern 2 are constituted by the concave portions 22b of the concave-convex structure layer 20 and the one surface 10a of the substrate 10, or constituted by the concave portions 22b of the concave-convex structure layer 20 and the concave portions 10b provided on the substrate 10.

In the uneven pattern 2 of the pattern master 1, the positional deviation α of the bottom point of each concave portion 2b in the direction perpendicular to the one surface 10a of the substrate 10 is 20nm or less.

Here, the bottom point of the concave portion 2b refers to a point located at the deepest position of each concave portion 2b in the direction perpendicular to the one surface 10a of the base 10. As shown in fig. 2, the positional deviation α of the bottom point of each concave portion 2b is a distance from the bottom point of the deepest concave portion to the bottom point of the shallowest concave portion among the plurality of concave portions 2b. Hereinafter, the position of the bottom point of the recess (or the position of the bottom point) refers to the position of the bottom point of the recess in the direction perpendicular to the one surface 10a of the substrate 10.

On the other hand, in the uneven pattern 2 of the pattern master 1, it is more preferable that the positional deviation of the apexes of the projections 2a in the direction perpendicular to the one surface 10a of the base 10 is smaller. However, it may exceed 5nm.

Here, the apex of the convex portion 2a refers to a point located at the highest position of each convex portion 2a in the direction perpendicular to the one surface 10a of the base 10. As shown in fig. 2, the positional deviation β of each convex portion 2a is a distance from the apex of the highest convex portion to the apex of the lowest convex portion among the plurality of convex portions 2 a. Hereinafter, the position of the apex of the convex portion (or the apex position) refers to the position of the apex of the convex portion in the direction perpendicular to the one surface 10a of the base 10.

The positional deviation of the bottom points of the recesses and the peaks of the protrusions was obtained by measuring the height of the pattern portion with an Atomic Force Microscope (AFM), and extracting 10 bottom points of the recesses and 10 peaks of the protrusions at random. The difference between the deepest and shallowest of the extracted 10 recess bottom points is defined as the deviation of the position of the recess bottom point. Then, the difference between the highest and lowest of the extracted 10 convex peaks is defined as the positional deviation of the convex peaks.

Further, regarding the degree of the deviation of the positions of the bottom points and the deviation of the positions of the top points of the concave portions of the concave-convex pattern, a Scanning Electron Microscope (SEM) image can be taken and observed of the cross section of the pattern master 1.

The height difference of the unevenness in the uneven pattern 2 is preferably 100nm or more, more preferably 200nm or more, and still more preferably 300nm or more. In view of preventing reflection, it is preferable that the difference in height between the irregularities is large. However, from the viewpoint of mechanical strength, it is 1 μm or less, and more preferably 500nm or less. The height difference referred to herein is a distance from the bottom point of the concave portion to the top point of the convex portion, and a distance between the center of variation in the top point position of the convex portion 2a and the center of variation in the bottom point position of the concave portion 2b of the uneven pattern 2 can be regarded as a height difference of the unevenness of the uneven pattern 2.

The uneven pattern 2 preferably has an average period of 400nm or less and is uneven. The average period is preferably 300nm or less, more preferably 200nm or less. Here, the period refers to an arrangement period of the convex portions or the concave portions, and as shown in fig. 1, the period can be determined by a distance T between the convex portions that are closest to each other across 1 concave portion in the concave-convex pattern 2 ₁ Or the distance T between the recesses closest to each other with 1 projection therebetween ₂ And (4) showing. In the uneven pattern 2, the arrangement period of the convex portions 2a and the concave portions 2b is not constant. Further, the convex portion shape and the concave portion shape are not uniform.

The average period can be obtained by, for example, taking a surface image of the fine uneven structure by SEM, performing image processing and binarization, and performing statistical processing.

The uneven pattern 2 may be composed of a plurality of isolated convex portions and a concave portion region surrounding the convex portions, or may be composed of isolated concave portions and a convex portion region surrounding the concave portions. In the former case, the shape and arrangement of the convex portions and the shape of the concave portion region may be uneven, and in the latter case, the shape and arrangement of the concave portions and the shape of the convex portion region may be uneven. Further, the uneven pattern may be formed unevenly in the convex region and the concave region.

Fig. 3 to 5 are SEM images obtained by imaging the concave-convex pattern of the pattern master of the example of the present invention from a direction perpendicular to the substrate. In each figure, a portion visually recognized as white is a convex portion, and a portion visually recognized as dark gray is a concave portion. In any case, the concave portions and the convex portions are formed unevenly in a sea-island structure-like uneven pattern. In the present specification, the term "uneven unevenness" refers to a sea-island structure-like unevenness in which the shapes of the concave portions and the convex portions are different from each other and the arrangement of the concave portions and the convex portions is not regular. In fig. 3, a concave-convex pattern is formed which is composed of a plurality of isolated convex portions and a concave portion region surrounding the convex portions. In fig. 4, a concave-convex pattern is formed, which is composed of a plurality of isolated concave portions and convex portions surrounding the concave portions. In fig. 5, the intermediate uneven pattern of fig. 3 and 4 is formed by mixing the continuous convex portion region and the continuous concave portion region.

As shown in fig. 6, it is preferable that an interdiffusion layer 15 in which a material constituting the concave-convex structure layer 20 and a material constituting one surface 10a of the base 10 are mixed with each other is formed in an interface region between the concave-convex structure layer 20 and the base 10.

By providing the interdiffusion layer 15, the adhesion between the uneven structure layer 20 and the substrate 10 can be improved. Since the concavo-convex structure layer 20 has high adhesiveness to the substrate 10, when manufacturing a flexible mold described later, it is possible to suppress peeling of the concavo-convex structure layer 20 and the substrate 10 when peeling the flexible mold from the concavo-convex structure layer.

As described above, the one surface 10a of the substrate 10 may be made of a material having a lower etching rate than the concave-convex structure layer 20 with respect to the etching gas used for etching the concave-convex structure layer 20. For example, when the uneven structure layer 20 is silicon, a fluorine-based gas, for example, sulfur hexafluoride (SF) is used as the gas for etching the uneven structure layer 20 ₆ ) And trifluoromethane (CHF) ₃ ) Preferably, the material having a lower etching rate than the uneven structure layer 20 with respect to the gas includes a metal such as nickel (Ni) and chromium (Cr), and silicon oxide (SiO) ₂ ) Sapphire, etc. When the uneven structure layer 20 is Cr, chlorine gas is suitable as a gas for etching the uneven structure layer 20, and sapphire is an example of a material having an etching rate lower than that of the uneven structure layer 20.

One surface 10a of the substrate 10 is preferably made of an oxide such as silicon oxide or sapphire, a nitride or carbide of a metal or the like, or a metal. Examples of the metal include nickel and chromium. The one surface 10a of the substrate 10 may be selected from these materials to function as an etching stopper in relation to the material of the uneven structure layer 20 and the etching gas.

On the other hand, the uneven structure layer 20 is preferably a layer containing silicon as a main component. The layer containing silicon as a main component means a layer containing silicon in an amount of 50 atomic% or more. The layer containing silicon as a main component is particularly preferably a polycrystalline silicon layer or an amorphous silicon layer.

In the case where the uneven structure layer 20 is a layer containing silicon as a main component, the one surface 10a of the base is preferably made of a material containing nickel as a main component. In this case, a nickel silicide layer as the interdiffusion layer 15 may be formed in the interface region between the concavo-convex structure layer 20 and the substrate 10. It is preferable that a nickel silicide layer be formed at the interface because adhesion between the uneven structure layer 20 and the substrate 10 is improved.

As for the base 10, at least one surface 10a may be made of a material having an etching stop function, but the entire base may be composed of the same material. On the other hand, the substrate 10 may be a laminate of 2 or more layers including a 1 st layer including one surface 10a and a 2 nd layer made of a material different from the 1 st layer.

Fig. 7 is a schematic cross-sectional view of the pattern master 3 according to embodiment 2.

The pattern master 3 includes all the structures of the pattern master 1 of embodiment 1. The pattern master 3 is different from the pattern master 1 of embodiment 1 in that the base 10 has a structure including a 1 st layer 11 having one surface 10a and a 2 nd layer 12 laminated in contact with the 1 st layer. The 1 st layer 11 is an etching stopper layer that functions as an etching stopper when the uneven structure layer 20 is formed by etching.

As the 1 st layer 11, the material constituting the one surface 10a of the substrate 10 described in embodiment 1 can be used. That is, a metal layer of silicon oxide, nickel, or the like can be used as the 1 st layer 11. The 1 st layer 11 can be formed on the 2 nd layer 12 by sputtering or the like.

As the 2 nd layer 12, for example, a silicon wafer can be used.

In this configuration, the same effects as those of the pattern master 1 of embodiment 1 can be obtained.

Method for manufacturing pattern master "

A method for manufacturing a pattern master according to an embodiment of the present invention will be described. Fig. 8 is a diagram showing steps of a method for manufacturing a pattern master according to an embodiment of the present invention, and this manufacturing method is a method for manufacturing the pattern master 3 according to embodiment 2 described above, as an example.

In the method for manufacturing a pattern master, first, a laminate 5 is prepared, the laminate 5 including a layer 20a to be processed and a thin film 25 containing aluminum in this order on one surface 10a of a base 10, and at least one surface 10a of the base 10 is made of a material having an etching stop function with respect to the layer 20a to be processed (step 1). Here, a substrate 10 in which a 1 st layer 11 serving as an etching stopper layer is formed on one surface of a 2 nd layer 12 is used.

Subsequently, the aluminum-containing thin film 25 is subjected to warm water treatment (step 2). For example, each laminate 5 is immersed in pure water 6 contained in a vessel 7 and subjected to a warm water treatment. By this warm water treatment, the textured layer 26 made of alumina hydrate is formed (step 3).

Then, the textured layer 26 and the layer to be processed 20a are etched from the textured layer 26 side made of alumina hydrate until the textured layer 26 is removed and the one surface 10a of the substrate 10 is exposed to the recessed portion provided on the layer to be processed 20a (step 4), and the layer to be processed 20a is processed into the textured layer 20 including the raised portions 22a and the recessed portions 22b (step 5).

Through the above steps, the pattern master 3 having the fine uneven pattern 2 on the surface can be obtained.

After the etching, a laminate including the substrate 10 and the uneven structure layer 20 provided on one surface 10a thereof may be subjected to a heat treatment, and the laminate after the heat treatment may be used as a pattern master.

It is known that: when the aluminum-containing thin film 25 is treated with warm water, aluminum oxide hydrate (Al) is formed on the surface thereof ₂ O ₃ ·H ₂ O) a fine textured structure as a main component. Here, the term "alumina hydrate" as a main component meansThe content of alumina hydrate in the textured layer is 50 mass% or more.

The aluminum-containing thin film 25 is preferably made of any one of aluminum, aluminum oxide, aluminum nitride, or aluminum oxynitride. Further, the film 25 may be made of an aluminum alloy. The "aluminum alloy" is a compound or a solid solution containing aluminum as a main component and at least one of elements such as silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), zinc (Zn), chromium (Cr), titanium (Ti), and nickel (Ni). In the thin film 25, the composition ratio of aluminum to all metal elements is preferably 80 mol% or more from the viewpoint of forming a textured structure (aluminum mineralized by water). Such a thin film containing aluminum as a main component is modified into an alumina hydrate such as gibbsite by warm water treatment, and an uneven structure is formed on the surface thereof.

The method for forming the thin film 25 containing aluminum on the layer to be processed 20a is not particularly limited. For example, a vapor phase method typified by a vapor deposition method, a sputtering method, an ion plating method, or a chemical vapor deposition method, or a sol-gel method in which an aluminum precursor solution is applied by a liquid phase method typified by a spin coating method, a dip coating method, or an ink jet method and then sintered can be used.

In the present specification, the "hot water treatment" refers to a treatment in which hot water is applied to a thin film containing aluminum. The hot water treatment is, for example, a method of immersing the laminate 5 having the aluminum-containing thin film 25 formed thereon in water at room temperature (preferably pure water in particular) and then boiling the water, a method of immersing the laminate 5 in hot water kept at a high temperature, a method of exposing the laminate to high-temperature steam, or the like. For example, in the present embodiment, the pure water 6 in the container 7 is heated and boiled by the heating plate 8, and the layered bodies 5 are immersed in each other. The time for boiling and immersion and the temperature of the hot water are appropriately set according to the desired uneven structure. The reference time is preferably 1 minute or more, and particularly, 3 minutes or more and 15 minutes or less. From the viewpoint of the mineralization of water and aluminum, the temperature of the warm water is preferably 60 ℃ or higher, and particularly preferably higher than 90 ℃. The higher the temperature, the shorter the treatment time. For example, when an aluminum thin film having a thickness of 10nm is boiled in warm water at 100 ℃ for 3 minutes, an uneven structure having randomly arranged uneven portions, that is, an uneven pattern of uneven portions, in which the interval between the projected portions is 50 to 300nm and the height of the projected portions is 50 to 100nm, can be obtained. The variation in the depth position of the concave portion and the height position of the convex portion is also large, and usually, the variation is 5nm or more or 10nm or more.

The thickness of the uneven structure layer 26 made of alumina hydrate (hereinafter, referred to as the 1 st uneven structure layer 26.) formed after the warm water treatment is defined as the height from the surface of the layer 20a to be processed to the apex of the convex portion. The thickness of the 1 st uneven structure layer 26 is preferably 130nm or more, and more preferably 200nm or more. The conditions for obtaining the uneven structure layer of 130nm or more vary depending on the material of the thin film containing aluminum as a precursor thereof, but the film thickness is preferably set to a film thickness of approximately 2nm or more and 20nm or less. Under the same hot water treatment conditions, the thickness of the uneven structure layer increases as the thickness of the aluminum film increases.

The thickness of the aluminum-containing thin film 25 and the thickness of the uneven structure layer 26 obtained by subjecting the thin film 25 to the hot water treatment can be determined by taking a cross-sectional SEM image in each step. However, since the cross section cannot be exposed in actual production, the thin film 25 may be produced by previously obtaining the relationship between the film thickness and the film formation time, the relationship between the film thickness of the thin film 25 and the thickness of the uneven structure layer 26, and the like, and using the previously obtained relationship.

In the method of manufacturing the pattern master of the present embodiment, the surface shape is receded by etching along the uneven structure from the side of the fine uneven structure made of the alumina hydrate, and the uneven structure reflecting the shape of the uneven structure of the alumina hydrate is formed on the layer to be processed 20 a. The uneven structure "reflecting" the aluminum-containing thin film means a state of a degree of similarity in some undulations without having a positional accuracy of the degree of (so-called transfer) of the convex or concave portion at a position corresponding one-to-one to each of the convex or concave portion of the uneven structure.

The laminate including the substrate 10 and the layer 20a to be processed is a member which becomes the pattern master 1 by processing the layer 20a to be processed. The shape of the substrate 10 is not particularly limited, and may be determined as appropriate according to the pattern master 1 to be manufactured. For example, a wafer-shaped or rectangular flat substrate can be used as the base 10. Further, a three-dimensionally shaped member having one curved surface (for example, a spherical surface) can also be used as the base.

At least one surface 10a of the substrate 10 may be made of a material having a lower etching rate than the layer to be processed 20a and functioning as an etching stopper when the layer to be processed 20a is etched.

The layer to be processed 20a is a layer of the concavo-convex structure layer 20 processed by etching to have convex portions and concave portions along the concavo-convex pattern of the pattern master 1. The layer to be processed 20a is preferably made of a material which has a higher etching rate than the 1 st concavo-convex structure layer 26 made of an oxide of aluminum oxide and is easily etched. If the etching selectivity of the layer 20a to be processed with respect to the 1 st uneven structure layer 26 is high, the layer 20a to be processed is etched more quickly than the 1 st uneven structure layer 26 after the layer 20a to be processed is exposed to the recessed portion of the 1 st uneven structure layer 26. Thus, the layer to be processed 20a can be processed into the 2 nd uneven structure layer 20 having irregularities with a greater level difference than the level difference of the 1 st uneven structure layer 26.

In the etching step, in order to suppress shape degradation due to side etching, anisotropic etching is preferably performed by irradiating an energy beam from the surface side of the fine uneven structure. Examples of such etching include reactive ion etching and reactive ion beam etching.

The etching gas G can be selected from argon (Ar) and oxygen (O) ₂ ) Nitrogen (N) ₂ ) Difluoromethane (CH) ₂ F ₂ ) Trifluoromethane (CHF) ₃ ) Tetrafluoromethane (CF) ₄ ) Octafluorocyclobutane (C) ₄ H ₈ ) Sulfur hexafluoride (SF) ₆ ) Carbon monoxide (CO) and carbon dioxide (CO) ₂ ) And chlorine (Cl) ₂ ) 1 or more of them. In particular, the etching gas preferably contains a halogen atom such as fluorine, chlorine, bromine, iodine, and astatine, and particularly preferably contains a fluorine atom. The pressure in the apparatus during etching is preferably 0.5Pa or more.

In the etching step, it is preferable that etching of the layer to be processed 20a after exposure to the recessed portion of the 1 st uneven structure layer 26 made of alumina hydrate is performed under the conditions of Rw > Ra > Rs, where Ra is an etching rate of the 1 st uneven structure layer 26, rw is an etching rate of the layer to be processed, and Rs is an etching rate of one surface of the base.

If the etching rate Rw of the layer to be processed 20a is greater than the etching rate Ra of the 1 st uneven structure layer 26, the etching of the layer to be processed 20a exposed to the recessed portions of the 1 st uneven structure layer 26 proceeds more rapidly than the etching of the 1 st uneven structure layer 26. Thus, the layer 20a to be processed can be processed into the 2 nd uneven structure layer 20 having unevenness with a height difference larger than that of the 1 st uneven structure layer 26.

The 1 st uneven structure layer 26 made of alumina hydrate has uneven unevenness, and the height of the convex portion and the depth of the concave portion are uneven, and differ from convex portion to concave portion. Therefore, the time from the start of etching to the exposure of the layer to be processed 20a to each recess of the 1 st uneven structure layer 26 is different. That is, the timing of starting the etching depends on the shape of the 1 st uneven structure layer 26 and differs according to the position of the surface of the layer 20a to be processed. Therefore, if the one surface 10a of the substrate 10 is exposed to the bottom of the recess at the position where the etching of the layer 20a to be processed is started early, the bottom of the recess formed at another position of the layer 20a to be processed may not reach the one surface 10a of the substrate 10.

However, since the etching rate Rs of the one surface 10a of the base 10 is smaller than the etching rate Ra of the layer 20a to be processed, in the case of being exposed from the recess formed on the layer 20a to be processed by etching the one surface 10a of the base 10, the progress of etching in the one surface 10a becomes slow. Although the one surface 10a of the base 10 is also slightly etched, since the etching rate of the layer 20a to be processed is larger than that of the base 10, etching of the recess in the layer 20a to be processed which does not reach the one surface 10a of the base 10 proceeds more quickly.

When the etching is performed using the 1 st uneven structure layer having uneven portions with low uniformity such as gibbsite as a mask in the case where there is no surface functioning as an etching stopper, the positional deviation of the bottom points of the recessed portions is large and exceeds 20nm. However, according to the manufacturing method of the present embodiment, since the 1 st layer 11 constituting the one surface 10a of the substrate 10 functions as the etching stopper as described above, the positions of the bottom points of the recesses 2b of the uneven pattern 2 formed by etching can be aligned in the vicinity of the one surface 10a of the substrate 10. Therefore, the positional deviation of the bottom points of the plurality of concave portions 2b of the uneven pattern 2 can be set to 20nm or less. Further, by adjusting the etching conditions, the variation can be set to 10nm or less, or 5nm or less. On the other hand, since the influence of uneven unevenness of the 1 st uneven structure layer remains at the apex positions of the respective convex portions of the uneven pattern 2, the variation in apex positions is generally larger than the variation in the positions of the base points.

As described above, according to the method of manufacturing a pattern master of the above-described embodiment, the thin film containing aluminum is formed on the layer to be processed provided on the surface of the base, and the pattern master in which the variation in the height of the bottom of the concave portion of the uneven pattern is suppressed can be obtained by a very simple process such as warm water treatment or etching treatment. Therefore, the pattern master can be manufactured with high throughput.

When the heat treatment is performed after the etching, it is preferable to perform the etching under the condition that the uneven structure layer 20 and the surface 10a having the etching stopper function are diffused into each other. For example, when the uneven structure layer 20 is made of silicon and the etching stopper layer is made of nickel, the heat treatment is preferably performed at a temperature of 350 ℃. There are advantages that the strength of the interface is increased by interdiffusion of the relief layer and the etch stop layer, and the durability when used as a pattern master is increased.

Method for manufacturing mould "

A method for manufacturing a mold according to an embodiment of the present invention will be described. A method of manufacturing a mold according to an embodiment is a method of manufacturing a mold having a transferred uneven pattern having the uneven pattern on a surface thereof, using the pattern master. Here, a case of manufacturing a flexible mold as a mold will be described. Fig. 9 is a diagram illustrating steps of a method of manufacturing a flexible mold according to an embodiment.

First, a pattern master is prepared (step 11). Here, the pattern master 3 of embodiment 2 is used. A resin composition layer 30, which is a material of a flexible mold, is formed on the uneven pattern 2 of the pattern master 3 (step 12). For example, the resin composition layer 30 is formed by applying an ultraviolet curable resin composition to the surface of the uneven pattern 2.

Then, the resin composition is cured to form the resin layer 31 (step 13). When the resin composition is an ultraviolet-curable resin composition, the resin composition is cured by irradiation with Ultraviolet (UV) light.

As the resin layer, for example, dimethylpolysiloxane (PDMS) is preferable. The resin composition is not limited to the ultraviolet curable type, and may be a thermosetting type resin, and in the case of the thermosetting type, it can be cured by heating.

Then, the resin layer 31 obtained by curing the resin composition is peeled from the pattern master 3 (step 14). The transfer concave-convex pattern 32 is formed by transferring the concave-convex pattern 2 of the pattern master 3 to one surface of the resin layer 31. The resin layer 31 provided with the transferred uneven pattern 32 is a flexible mold (hereinafter referred to as a flexible mold 31).

The transfer concave-convex pattern 32 of the flexible mold 31 is a reverse pattern of the concave-convex pattern 2 of the pattern master 3. In the uneven pattern 2 of the pattern master 3, since the variation of the bottom points of the concave portions is suppressed, the transferred uneven pattern 32 as a reverse pattern becomes the variation α of the positions of the apexes of the convex portions 32a ₂ Suppression is obtained. Preferably the deviation alpha of the vertex position ₂ Is 20nm or less. Deviation alpha ₂ Preferably 10nm or less, more preferably 5nm or less. On the other hand, the deviation β of the bottom point position of the concave portion 32b of the transferred uneven pattern 32 ₂ The smaller the size, the more preferable the size, but the deviation β (see fig. 1.) of the peak position of the convex portion 2a of the concave-convex pattern 2 corresponding to the pattern master 3 may exceed 5nm.

As described above, in the flexible mold 31, the variation in the positions of the apexes of the convex portions 32a of the concave-convex pattern 32 is suppressed, and the convex portions have a uniform height. Therefore, when the mold is used for nanoimprinting, the thickness of the resist residual film can be made uniform, and a good uneven pattern can be formed on the surface of the workpiece.

The flexible mold 31 can be used for forming an uneven structure on the surface of various substrates. For example, the present invention can be used to form an uneven pattern that functions as an antireflection structure on the surface of an optical element.

In the above-described method for manufacturing a mold using the pattern master, for example, nickel is electroformed on the uneven pattern of the pattern master, an electroformed product having the transferred uneven pattern of the pattern master is formed, and the electroformed product is peeled off, whereby a mold made of the electroformed product can also be manufactured. In this case, too, a mold having a small variation in the apex position of the convex portion to which the uneven pattern is transferred can be produced. Therefore, as in the case of the flexible mold, the thickness of the resist remaining film can be made uniform, and a good uneven pattern can be formed on the surface of the workpiece.

Method for producing substrate having uneven structure on surface "

A method for manufacturing a substrate having an uneven structure on a surface thereof according to an embodiment of the present invention will be described. Fig. 10 is a diagram illustrating steps of a method for manufacturing a substrate according to an embodiment.

First, a flexible mold is produced using the pattern master. The manufacturing process of the flexible mold is the same as the manufacturing method of the flexible mold according to the above-described embodiment. Here, the flexible mold 31 obtained through the above-described flexible mold manufacturing process is used, but a mold manufactured by electroforming using a pattern master may be used.

The substrate to be processed is preferably an optical member such as a sapphire substrate, various glass substrates, or a lens.

For example, an ultraviolet curable resist 50 is applied to a flat surface of the substrate 40 (step 21). The flexible mold 31 is pressed against the resist 50 so that the transferred uneven pattern 32 is pressed against the resist 50 (step 22).

Ultraviolet rays are irradiated onto the resist 50 through the substrate 40 to be processed, and the resist 50 is cured (step 23). The resist 50 is cured to form a resin layer 51 having a 2 nd transfer uneven pattern 52 on the surface thereof, which is obtained by transferring the 1 st transfer uneven pattern 32 of the flexible mold 31.

The flexible mold 31 is peeled from the surface of the resin layer 51 (step 24). Thereby, a structure having the resin layer 51 having the 2 nd transfer uneven pattern 52 on the sapphire substrate 40 was obtained. At this time, since the height of the apex of the convex portion of the flexible mold 31 is uniform, the remaining film thickness of the resist becomes uniform.

The 2 nd transfer concave-convex pattern 52 of the resin layer 51 becomes the same concave-convex pattern as the concave-convex pattern 2 of the pattern master 3. Therefore, the deviation α of the bottom point position of the concave portion 52b ₃ The deviation beta of the peak position of the convex part 52a is restrained ₃ Is large. The magnitude of the deviation slightly changes by repeating the transfer, but the bottom point position deviation α ₃ Preferably 20nm or less, more preferably 10nm or less, and further preferably 5nm or less. On the other hand, the deviation β of the apex position of the convex portion 52a ₃ Over 5nm. The small deviation of the bottom point position of the concave portion 52b means that the remaining film thickness of the resist is uniform.

Next, etching is performed using the resin layer 51 as a mask (step 25).

As a pretreatment, the residual film of the resin layer 51 is removed. The resin layer 51 remaining from the recesses 52b of the transferred uneven pattern 52 of the resin layer to the substrate 40 is a residual film, and the residual film is removed by etching or ashing to expose the surface of the substrate 40. If the residual film has variations, it takes time to remove the thick residual film, and the ashing process causes the shape of the discharge portion to be gentle and the height to be reduced, which results in a reduction in the function as a mask when etching the substrate. However, in the present embodiment, since the flexible mold 31 is used, the thickness of the residual film is uniform, and the residual film in each concave portion 52b can be removed well for a certain residual film processing time. For removing the residual film, oxygen, argon, fluorine-based gas, or the like can be used.

After the substrate 40 is exposed to the recesses 52b of the resin layer 51, the substrate 40 is etched using an etching gas having a large etching selectivity with respect to the resin layer 51. By this etching, the uneven pattern 42 corresponding to the 2 nd transfer uneven pattern 52 of the resin layer 51 can be formed on the surface of the substrate 40 to be processed (step 25).

In this way, the substrate 41 having a fine uneven pattern on the surface can be produced.

Examples

Hereinafter, a method for manufacturing a pattern master according to an embodiment of the present invention will be described.

A laminate comprising a substrate having a nickel layer laminated on a silicon wafer and a silicon layer formed on the nickel layer is prepared. The nickel layer is the 1 st layer comprising one surface of the substrate, and the silicon wafer corresponds to the 2 nd layer. The silicon layer formed on the nickel layer is a layer to be processed. The thickness of the nickel layer was set to 20nm and the thickness of the silicon layer was set to 300 nm.

Then, an aluminum film of 10nm was formed as a thin film containing aluminum on the surface of the silicon layer by a sputtering method. Next, the laminate having the aluminum film formed thereon was immersed in warm water at 100 ℃ for 3 minutes and subjected to warm water treatment, thereby obtaining a 1 st uneven structure layer made of an alumina hydrate. Then, the surface on which the 1 st uneven structure layer was formed was etched using a reactive ion etching apparatus. Etching is performed until the 1 st concavo-convex structure layer is removed. Further, SF was used as an etching gas ₆ And CHF ₃ The mixed gas of (2).

By the above etching, the 1 st concavo-convex structure layer is removed, and the layer to be processed is processed into a 2 nd concavo-convex structure layer including convex portions and concave portions, thereby obtaining a pattern master having a fine concavo-convex pattern on the surface.

Fig. 11 and 12 are SEM images of the surface and cross section of the pattern master manufactured by the above-described manufacturing method. In the image of the surface shown in fig. 11, the convex portions were observed to be white and the concave portions were observed to be black, and a concave-convex pattern in which uneven concave-convex portions were formed was found. The image of the cross section shown in fig. 12 clearly shows that: etching is stopped in the nickel layer, the bottom point position of the recess is on the surface of the nickel layer, and a concave-convex pattern with very small deviation of the bottom point position of the recess is formed. In addition, the image shown in fig. 12 includes a cross section of the side wall of the slope shape of the concave portion (or the convex portion). In this example, an uneven pattern having a height of a projection (depth of a recess) of about 300nm was obtained.

The disclosure of japanese patent application No. 2018-103819, filed on 2018, 5, and 30, is incorporated herein by reference in its entirety.

All documents, patent documents, and technical standards described in the present specification are incorporated by reference into the present specification to the same extent as if each document, patent document, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A pattern master having a fine uneven pattern on the surface thereof,

the pattern master comprises a base and a concavo-convex structure layer provided on one surface of the base and including a plurality of convex portions and a plurality of concave portions along the concavo-convex pattern,

at least the one face of the substrate is made of a material having an etching stop function,

the substrate is exposed to the bottom of at least a part of the recesses of the concavo-convex structure layer,

in the uneven pattern, a deviation of a bottom point position of each concave portion of the uneven pattern in a direction perpendicular to the one surface is 20nm or less,

an interdiffusion layer is formed in an interface region between the concavo-convex structure layer and the substrate, and the interdiffusion layer is formed by mixing a material constituting the concavo-convex structure layer and a material constituting the one surface of the substrate.

2. The pattern master according to claim 1,

the uneven pattern is uneven and has an average period of 400nm or less.

3. The pattern master according to claim 1 or 2,

in the uneven pattern, a variation in position of a vertex of each convex portion of the uneven pattern in a direction perpendicular to the one surface exceeds 5nm.

4. The pattern master according to claim 1 or 2,

the one face of the substrate is made of silicon oxide.

5. The pattern master according to claim 1 or 2,

the one face of the base is made of metal.

6. The pattern master according to claim 1 or 2,

the concavo-convex structure layer is a layer with silicon as a main component.

7. The pattern master according to claim 1 or 2,

the concavo-convex structure layer is a layer having silicon as a main component, and the one surface of the substrate is a layer having nickel as a main component.

8. The pattern master according to claim 7,

and a nickel silicide layer is formed in the interface area of the concave-convex structure layer and the substrate.

9. The pattern master according to claim 6,

the concave-convex structure layer is made of polycrystalline or amorphous silicon.

10. The pattern master according to claim 1 or 2,

the substrate is composed of a laminate including: a 1 st layer comprising the one face; and a 2 nd layer made of a different material from the 1 st layer.

11. A method of manufacturing a pattern master, comprising the steps of:

preparing a laminate comprising a layer to be processed and a thin film containing aluminum in this order on one surface of a base, at least the one surface of the base being made of a material having an etching stop function,

subjecting the film containing aluminum to warm water treatment, thereby forming a 1 st concavo-convex structure layer made of alumina hydrate,

etching the 1 st concavo-convex structure layer and the layer to be processed from the 1 st concavo-convex structure layer side until the 1 st concavo-convex structure layer is removed and the one surface of the base is exposed to at least a part of a concave portion formed on the layer to be processed, processing the layer to be processed into a 2 nd concavo-convex structure layer including a plurality of convex portions and a plurality of concave portions,

after the etching step, heat treatment is performed under a condition that the 2 nd uneven structure layer and the surface of the base body having the etching stop function are diffused into each other.

12. The method of manufacturing a pattern master according to claim 11,

in the etching step, when the etching rate of the 1 st uneven structure layer is Ra, the etching rate of the layer to be processed is Rw, and the etching rate of the base is Rs,

and etching the processed layer after being exposed to the concave part of the 1 st concave-convex structure layer is carried out under the condition that Rw is more than Ra and Rs.

13. The method of manufacturing a pattern master according to claim 11 or 12,

at least the one surface of the substrate is made of silicon oxide or metal.

14. The method of manufacturing a pattern master according to claim 11 or 12,

the layer to be processed is a layer containing silicon as a main component.

15. The method of manufacturing a pattern master according to claim 11 or 12,

in the etching, an etching gas containing halogen atoms is used.

16. The method of manufacturing a pattern master according to claim 15,

the halogen atom is a fluorine atom.

17. The method of manufacturing a pattern master according to claim 11 or 12,

the thin film containing aluminum has a film thickness of 2nm to 20nm.

18. A method for manufacturing a mold, wherein,

using the pattern master according to any one of claims 1 to 10,

19. The method of manufacturing a mold according to claim 18,

forming a resin composition layer along the concave-convex pattern of the surface of the pattern master,

curing the resin composition layer, thereby forming a resin layer having a transferred concavo-convex pattern of the concavo-convex pattern,

and peeling the resin layer from the pattern master to obtain a flexible mold having the transfer concave-convex pattern on the surface.

20. A method for producing a substrate having a concavo-convex structure on a surface thereof,

using the pattern master according to any one of claims 1 to 10, producing a 1 st transfer concave-convex pattern mold having the concave-convex pattern transferred to the pattern master on a surface thereof,

a resist is applied to one surface of a substrate to be processed,

pressing the 1 st transfer uneven pattern of the mold against the resist, thereby transferring the 1 st transfer uneven pattern onto the resist to form a 2 nd transfer uneven pattern,

curing the resist on which the 2 nd transfer concave-convex pattern is formed, thereby forming a 2 nd resin layer having the 2 nd transfer concave-convex pattern,

etching the 2 nd resin layer and the substrate to be processed from the 2 nd resin layer side using the 2 nd resin layer having the 2 nd transferred uneven pattern as a mask, thereby forming an uneven pattern on the surface of the substrate to be processed.