JP2019054235A - Pattern formation method and method for manufacturing imprint mold by use thereof, and imprint molds to be used therefor - Google Patents

Abstract

To provide: a pattern formation method for forming plural kinds of patterns different in pattern density and dimension with high precision and yield; and a method for manufacturing an imprint mold by use of the pattern formation method.SOLUTION: A pattern formation method comprises the steps of: forming, on one face of a workpiece 11, a core material pattern 21 having a low-convex part 22 for first fine pattern formation, which has a pitch double the pitch of a first fine pattern, and a high-convex part 24 for forming a second fine pattern larger, in dimension, than the first fine pattern; forming a side wall material film 41 so as to cover the core material pattern 21; subsequently, etching the side wall material film 41 and the core material pattern 21 to form a side wall pattern 45 on the remaining core material pattern 21; subsequently, removing the low-convex part 22 so that the high-convex part 24 of the core material pattern 21 is left; and etching the workpiece 11 while using the side wall pattern 45 and the remaining high-convex part 24 as an etching mask, thereby forming first and second fine patterns.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pattern forming method for simultaneously forming a plurality of types of patterns having different pattern densities and dimensions, an imprint mold manufacturing method using the same, and an imprint mold used therefor.

For example, in a semiconductor device, further miniaturization of a pattern is required due to a demand for high-speed operation and low power consumption operation.In recent years, as a technique for further improving the resolution, by photolithography using a phase shift mask, Manufactures fine patterns such as VLSI. However, in order to cope with further miniaturization, the limit of the method using only photolithography has been pointed out due to the problem of the exposure wavelength.
In order to solve such a problem, a pattern forming film is formed so as to cover the core material pattern formed by using the photolithography method described above, and the pattern forming film is etched to form a sidewall of the core material pattern. A method using a so-called side wall process is proposed in which a pattern structure is formed on the substrate, and thereafter the core material pattern is removed to leave the pattern structure, and this pattern structure is used as an etching mask (Patent Document 1). ).
In addition, in a semiconductor device, there may be a region where a wiring pattern or the like is formed with a high density and a region with a low pattern density such as a peripheral circuit region. A method of forming using a process has been proposed (Patent Document 2).
In recent years, a pattern forming technique using an imprint method has attracted attention as a fine pattern forming technique that replaces the photolithography technique. The imprint method is a pattern formation technology that transfers a fine structure at an equal magnification by using a mold member (mold) having a fine concavo-convex structure and transferring the concavo-convex structure to a molding object, and is not limited to a semiconductor device. Applications in various fields are being promoted.

JP 2009-10317 A JP 2009-246332 A

In the fine pattern forming method disclosed in Patent Document 2, a mold pattern having a first pitch twice larger than the pitch of the fine pattern to be finally formed is formed in the high-density pattern region. A fine mask layer is formed over the entire area so as to cover the pattern, and then an upper hard mask is formed in the low density pattern region. However, since the dimensions of the mold pattern and the fine mask layer are extremely fine, in a series of processes including spin coating to form the upper hard mask layer, external force such as surface tension or centrifugal force due to the material used, It may act on the fine mask layer and cause collapse, breakage, peeling or the like. When such a mold pattern or fine mask layer falls down, breaks, peels off, there is a problem that it becomes difficult to form a fine pattern in a high-density pattern region.
The present invention has been made in view of the above circumstances, and uses a pattern forming method for forming a plurality of types of patterns having different pattern densities and dimensions with high accuracy and yield, and this pattern forming method. An object of the present invention is to provide an imprint mold for easily and surely implementing an imprint mold manufacturing method, such a pattern forming method, and an imprint mold manufacturing method.

  In order to achieve such an object, the pattern forming method of the present invention is a pattern forming method in which a first fine pattern and a second fine pattern having a dimension larger than the first fine pattern are simultaneously formed on the same surface. A core pattern having a low convex portion for forming a first fine pattern having a pitch twice as large as the pitch of the first fine pattern and a high convex portion for forming the second fine pattern. Formed on one surface of the workpiece, forming a sidewall material film so as to cover at least the core material pattern, etching the sidewall material film and the core material pattern, and remaining the core material pattern A side wall pattern made of the side wall material film is formed on a side wall, the low convex portion is removed so that the high convex portion of the core material pattern remains, and the side wall pattern and before High protrusion was the like to form the the workpiece by etching the first fine pattern the second fine pattern configuration as an etching mask.

As another aspect of the present invention, the high convex portion of the core material pattern is configured to be continuous with a part of the low convex portion, and the high convex portion protrudes from the low convex portion. It was set as the structure which has the inclination which an upper part becomes small rather than the bottom part of the site | part to do on a side surface.
As another aspect of the present invention, the high convex portion of the core material pattern is separated from the low convex portion.
As another aspect of the present invention, the sidewall material film is formed after the core material pattern is subjected to a slimming treatment for reducing the core material pattern to a desired dimension.
As another aspect of the present invention, an curable resist is supplied to one surface of the workpiece, and an imprint mold has a shallow concave portion corresponding to the low convex portion and a deep concave portion corresponding to the high convex portion. The core is formed by separating the imprint mold after the resist is spread between the imprint mold and the workpiece, and the resist is cured by bringing the workpiece into close proximity. It was set as such.

As another aspect of the present invention, an electron beam sensitive or light sensitive resist is applied to one surface of the workpiece, and the high convex base and the low convex are formed by an electron beam lithography method or a photolithography method. A resist pattern to be a part is formed, and then an electron beam sensitive or light sensitive resist is applied so as to cover the base part and the low convex part, and the electron beam lithography method or the photolithography method is applied to the base part. It was set as the structure which forms the said core material pattern by forming a resist pattern and making it the said high convex part.
As another aspect of the present invention, an imprint mold having a concave portion corresponding to the low convex portion and a concave portion corresponding to a shape of the high convex portion up to the same height as the low convex portion is prepared, A curable resist is supplied to one surface of the workpiece, the imprint mold and the workpiece are brought close to each other, the resist is spread between the imprint mold and the workpiece, After the resist is cured, the imprint mold is separated to make the base part of the high convex part and the low convex part, and then the electron beam sensitive type or the light sensitive type so as to cover the base part and the low convex part. A configuration in which a core material pattern is formed by applying a resist and forming a resist pattern on the base by electron beam lithography or photolithography to form the high convex portion. It was.

  As another aspect of the present invention, a first thin film is formed on one surface of the workpiece using the first material for the core material pattern, and then the core is different in etching resistance from the first material. A second thin film is formed on the first thin film using a second material for a material pattern, and an electron beam sensitive or light sensitive resist is applied on the second thin film, and then an electron beam lithography method or a photolithography method. Forming a first etching mask, and etching the second thin film through the first etching mask to form a pattern of the second thin film on the first thin film to form an upper pattern of the high convex portion, An electron beam sensitive or light sensitive resist is applied on the upper pattern and the first thin film, and a second etching mask is formed by an electron beam lithography method or a photolithography method, (2) etching the first thin film through an etching mask to form the low convex portion, forming a base portion of the high convex portion, and forming the high convex portion integrally with the upper pattern; It was set as the structure which forms a pattern.

  The imprint mold manufacturing method of the present invention includes a base material and a concavo-convex structure located on one surface of the base material, and the concavo-convex structure is difficult or impossible to be resolved by an electron beam lithography method. In an imprint mold manufacturing method including a first fine pattern having a dimension and a second fine pattern having a dimension that can be resolved by an electron beam lithography method, any one of the above-described methods is provided on one surface of the mold substrate. The pattern forming method is used to form the recesses constituting the first fine pattern and the recesses constituting the second fine pattern.

  An imprint mold of the present invention is an imprint mold used in a pattern forming method for simultaneously forming a first fine pattern and a second fine pattern having a dimension larger than the first fine pattern on the same surface. And a concavo-convex structure region set on one surface of the substrate, and a concavo-convex structure located in the concavo-convex structure region, wherein the concavo-convex structure is twice as large as the pitch of the first fine pattern. And a second recess having an opening corresponding to the second fine pattern and deeper than the first recess.

As another aspect of the present invention, the second concave portion of the concavo-convex structure is configured to be continuous with a part of the first concave portion.
As another aspect of the present invention, the partition wall is positioned between the second recess and the first recess of the core pattern.

In the pattern forming method of the present invention, a plurality of types of patterns having different pattern densities and dimensions can be formed with high accuracy and yield by using a sidewall process. According to the present invention, a semiconductor device having a plurality of types of patterns having different pattern densities and dimensions, or an imprint mold having a plurality of types of concavo-convex structures having different pattern densities and sizes can be manufactured with high accuracy and yield. Can do.
In the imprint mold manufacturing method of the present invention, a fine pattern having dimensions that are difficult or impossible to resolve by an electron beam lithography method and a large pattern having dimensions that can be resolved are simultaneously formed on the mold substrate. Compared to the conventional imprint mold manufacturing method, in which fine pattern formation and large pattern formation are performed in separate steps, the process can be simplified. An imprint mold having a concavo-convex structure having a first fine pattern having a dimension that is difficult or impossible to image and a second fine pattern having a dimension that can be resolved by an electron beam lithography method is manufactured with high accuracy and yield. be able to.
Moreover, the imprint mold of this invention can make the implementation of the pattern formation method of this invention, and the manufacturing method of an imprint mold easy and reliable.

FIG. 1 is a process diagram for explaining an embodiment of a pattern forming method of the present invention. FIG. 2 is a process diagram for explaining an embodiment of the pattern forming method of the present invention. FIG. 3 is a process diagram for explaining another embodiment of the pattern forming method of the present invention. FIG. 4 is a process diagram for explaining another embodiment of the pattern forming method of the present invention. FIG. 5 is a process diagram for explaining another embodiment of the pattern forming method of the present invention. FIG. 6 is a schematic cross-sectional view showing an embodiment of an imprint mold of the present invention. FIG. 7 is a partially enlarged cross-sectional view of the imprint mold shown in FIG. FIG. 8 is a partially enlarged sectional view corresponding to FIG. 7 showing another embodiment of the imprint mold of the present invention. FIG. 9 is a partially enlarged sectional view corresponding to FIG. 7 showing another embodiment of the imprint mold of the present invention. FIG. 10 is a process diagram for explaining an example of forming a core material pattern in the pattern forming method of the present invention using the imprint mold of the present invention. FIG. 11 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention using the imprint mold of the present invention. FIG. 12 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 13 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 14 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 15 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 16 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 17 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 18 is a process diagram for explaining another example of forming a core material pattern in the pattern forming method of the present invention. FIG. 19 is a process chart of pattern formation for explaining another example of the workpiece used in the pattern formation method of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that the drawings are schematic or conceptual, and the dimensions of each member, the ratio of sizes between the members, etc. are not necessarily the same as the actual ones, and represent the same members. However, in some cases, the dimensions and ratios may be different depending on the drawing.
[Pattern Forming Method / Imprint Mold Manufacturing Method]
The pattern forming method of the present invention is a pattern forming method in which a first fine pattern and a second fine pattern having a size larger than the first fine pattern are simultaneously formed on the same surface. A pattern having a dimension that is difficult or impossible to be resolved by a lithography method such as a method or a photolithography method (a dimension that is less than the resolution limit (limit exposure line width) of the lithography method) can be formed. Dimensions that are difficult to resolve by the above lithography method may be possible under specific process conditions, but stable pattern formation is difficult, pattern dimension fluctuations, and pattern edge roughening It is a dimension that causes problems such as. On the other hand, the second fine pattern having a size larger than that of the first fine pattern is a pattern having a dimension that can be resolved by a lithography method such as an electron beam lithography method or a photolithography method, and does not cause the above problems. It is a pattern that can be formed by lithography.

(First embodiment)
1 and 2 are process diagrams for explaining an embodiment of the pattern forming method of the present invention.
In the present invention, first, the core material pattern 21 is formed on one surface of the workpiece 11 (FIG. 1A). In the illustrated example, the workpiece 11 is such that a hard mask material layer 14 as a first workpiece is positioned on one surface of a base material 12 as a second workpiece, and on the hard mask material layer 14. The core material pattern 21 is formed on the substrate.

  As the base material 12 that is the second processed body, for example, when the purpose of pattern formation is the manufacture of an imprint mold, an appropriate material can be selected as the base material of the imprint mold. Specifically, when the resist used in imprinting using the imprint mold to be manufactured is photocurable, a material that can transmit irradiation light for curing them can be used, for example, In addition to glass such as quartz glass, silicate glass, calcium fluoride, magnesium fluoride, and acrylic glass, sapphire and gallium nitride, and resins such as polycarbonate, polystyrene, acrylic, and polypropylene, or any laminated material thereof Can be used. Further, when the resist to be used is not photocurable, or when it is possible to irradiate light for curing the resist from the side of the pattern formation substrate used in imprinting, the base material 12 has optical transparency. In addition to the above materials, for example, metals such as silicon, nickel, titanium, and aluminum, alloys thereof, oxides, nitrides, or any laminated material thereof can be used. When the purpose of pattern formation is to manufacture semiconductor elements, fine wirings, etc., the base material 12 as the second processed body is made of metal such as silicon, nickel, titanium, aluminum, and alloys, oxides, nitrides thereof. Or these arbitrary laminated materials can be used. Furthermore, the material of the base material 12 that is the second processed body can be appropriately selected according to the purpose of pattern formation.

  As the hard mask material layer 14 that is the first processed body, a metal or a metal compound that can be dry-etched using the etching selectivity with the base material 12 that is the second processed body is used, and a vacuum process such as sputtering is performed. It can be formed by a film method. Examples of the above metals and metal compounds include metals such as chromium, tantalum, aluminum, molybdenum, titanium, zirconium, and tungsten, alloys of these metals, metal oxides such as chromium oxide and titanium oxide, chromium nitride, and titanium nitride. Metal intermetallic compounds such as gallium arsenide and the like. The thickness of such a hard mask material layer 14 depends on the etching selectivity during dry etching of the hard mask material layer 14 through the side wall pattern and the high convex portion described later, and the dryness of the substrate 12 through the hard mask described later. The thickness can be set in consideration of the etching selection ratio at the time of etching and the thickness range cannot be set generally. For example, it can be set appropriately within a range of 3 to 50 nm, preferably 3 to 10 nm.

  The core material pattern 21 formed on the hard mask material layer 14 that is the first processed body of the workpiece 11 has a pitch that is twice the pitch of the first fine pattern to be formed (pitch P1 described later). It has the low convex part 22 for the 1st fine pattern formation which has P2, and the high convex part 24 for the 2nd fine pattern formation. In the core material pattern 21, the high protrusions 24 are continuous with some of the low protrusions 22. In the illustrated example, the boundary between the high protrusions 24 and the low protrusions 22 is indicated by a chain line for convenience. Yes. The height H1 and width W1 of the low convex portion 22 constituting the core material pattern 21 and the height H2 and width W2 of the high convex portion 24 are the height and width required for the side wall pattern to be formed as described later. And can be set as appropriate in consideration of the dimension of the second fine pattern and the like. In addition, the height H2 of the high convex portion 24 is preferably at least twice the height H1 of the low convex portion 22. When the height H2 of the high convex portion 24 is less than twice the height H1 of the low convex portion 22, it is located on the side wall of the high convex portion 24 in the removal of the low convex portion 22 of the core material pattern 21 described later. The side wall pattern 45b as will be described later may fall down and disappear, which is not preferable. Examples of the material constituting the core pattern 21 include a material obtained by curing an electron beam sensitive resist, a light sensitive resist, a thermosetting resist, or the like, or polysilicon, silicon oxide, silicon nitride, carbonized carbon. Examples include silicon-based compounds such as silicon, which can be appropriately selected in consideration of the removability of a core material pattern, which will be described later, and the etching selectivity with the hard mask material layer 14. The formation of the core material pattern 21 will be described later.

  In the present invention, the core material pattern 21 may be subjected to a slimming treatment, and then a sidewall material film as a next step may be formed. In the present invention, slimming is to narrow the pattern width of the core material pattern 21 by wet etching or dry etching (including oxygen plasma treatment). For example, by performing slimming by oxygen plasma treatment, the pattern width can be reduced to about ½ without changing the pattern pitch of the core material pattern 21 formed first. When the slimming process is performed on the core material pattern 21, the height H1 and the width W1 of the low convex part 22 and the height H2 and the width W2 of the high convex part 24 after the slimming process are required for the sidewall pattern. The dimensions of the core material pattern 21 before the slimming process and the conditions for the slimming process are set so that the dimensions are set in consideration of the height, width, dimensions of the second fine pattern, and the like.

Next, a sidewall material film 41 is formed on the hard mask material layer 14 so as to cover the core material pattern 21 (FIG. 1B). The sidewall material film 41 can be formed by, for example, a low temperature vacuum film forming method such as an ALD method (atomic layer deposition method) or a CVD method (chemical vapor deposition method). In particular, the ALD method can be suitably used because it can be accurately formed at a low temperature regardless of the shape of the surface on which the atomic layer is deposited, such as an uneven surface or a curved surface.
Such a sidewall material film 41 does not damage the core material pattern 21 at a temperature sufficiently lower than the glass transition temperature of the material constituting the core material pattern 21, for example, 20 to 100 ° C., preferably about room temperature. It can be formed using a material that can be formed into a film. For example, the hard mask material layer 14 is a metal layer, and examples of the material of the sidewall material film 41 that can exhibit etching resistance in dry etching of the hard mask material layer 14 include silicon oxide, silicon nitride, and silicon oxynitride. Examples thereof include silicon-based materials, aluminum-based materials such as aluminum oxide, hafnium-based materials such as hafnium oxide, and titanium-based materials such as titanium nitride.
The sidewall material film 41 to be formed may be a single layer or a laminated film of two or more layers. The film thickness of the sidewall material film 41 is preferably set to a film thickness (a film thickness corresponding to a half pitch design) that is 1/2 of the pitch of the first fine pattern (pitch P1 described later). A series of atomic layers can be successively stacked until a desired thickness on the order of a few nm is obtained.

Next, the sidewall material film 41 and the core material pattern 21 are etched and etched back to expose the hard mask material layer 14, and the sidewall material film 41 is formed on the sidewall of the remaining core material pattern 21. leave. Thereby, the side wall pattern 45a which consists of the side wall pattern 45a located in the side wall of the low convex part 22 of the core material pattern 21 and the side wall pattern 45b located in the side wall of the high convex part 24 is formed (FIG.1 (C)). Etch back is an operation of cutting the entire surface in the thickness direction by dry etching, and can be performed using an appropriate etching gas according to the material constituting the sidewall material film 41. For example, when the sidewall material film 41 is made of silicon oxide, etching back can be performed using a fluorine-based gas such as CF ₄ , CHF ₃ , or C ₂ F ₆ as an etching gas.

Next, the low convex portion 22 is removed so that the high convex portion 24 of the core material pattern 21 remains (FIG. 2A). Such removal of the core material pattern 21 can be performed by, for example, selective dry etching using oxygen plasma. By removing the low convex portion 22 as described above, the low convex portion 22 continuing to the high convex portion 24 is removed except for a portion located at the lower portion of the side wall pattern 45b, and also for removing the low convex portion 22. Corresponding loss of height occurs in the high convex portion 24. Therefore, although the height of the high convex part 24 falls, the side wall pattern 45b located on the side wall of the high convex part 24 remains.
Next, the hard mask material layer 14 which is the first workpiece is dry-etched using the sidewall pattern 45 and the remaining high convex portions 24 as an etching mask to form a hard mask 15 (FIG. 2B). ). The hard mask 15 thus formed has a first fine pattern forming hard mask 15a located under the side wall pattern 45a, and a second fine pattern forming hard mask 15a located under the high convex portion 24 and the side wall pattern 45b. It consists of a hard mask 15b.

Next, the sidewall pattern 45 is removed, the hard mask 15 is used as an etching mask, the substrate 12 as the second workpiece is dry etched (FIG. 2C), and then the hard mask 15 is removed (FIG. 2). (D)). Thereby, the 1st fine pattern 13a of the pitch P1 and the 2nd fine pattern 13b with a dimension larger than this 1st fine pattern 13a can be simultaneously formed in the same surface of the base material 12. FIG. Further, by selecting a material suitable for the base material of the imprint mold as described above as the base material 12, the first fine pattern 13a having the pitch P1 on the same surface of the base material 12, and the first fine pattern 13a. An imprint mold provided with the second fine pattern 13b having a larger dimension than that can be manufactured.
In the present invention, ½ (half pitch) of the pitch P1 of the first fine pattern 13a is set to a dimension that makes it difficult or impossible to form a pattern by a lithography method such as an electron beam lithography method or a photolithography method. be able to. In the above example, dry etching of the substrate 12 is performed after the sidewall pattern 45 is removed, but the removal of the sidewall pattern 45 may be performed after the dry etching of the substrate 12.

  FIG. 3 is a process for explaining an example in which the shape of the high convex portion of the core material pattern formed on the hard mask material layer 14 constituting the workpiece 11 is changed in the pattern forming method described above. FIG. In this embodiment, the high convex portion 24 of the core material pattern 21 ′ formed on the hard mask material layer 14 has a bottom portion 24 b (on the side surface 24 c, which protrudes from the low convex portion 22 continuous to the high convex portion 24. The upper portion 24a has a slope that is smaller than that (shown with a chain line) (FIG. 3A). Then, the sidewall material film 41 is formed on the core material pattern 21 ′ having the high convex portion 24 having such a shape, as in the embodiment of the pattern forming method, and the sidewall material film 41 and the core material pattern are formed. An etching process is performed on 21 ′, and etching back is performed. From the side wall pattern 45a located on the side wall of the low convex portion 22 and the side wall pattern 45b located on the side wall of the high convex portion 24 of the remaining core material pattern 21 ′. A side wall pattern 45 is formed (FIG. 3B). The side wall pattern 45b formed in this way is in a state inclined toward the center of the high convex portion 24 as compared to the side wall pattern 45b (see FIG. 1C) formed in the above-described embodiment. Therefore, after that, in the step of removing the low convex portion 22 so that the high convex portion 24 of the core material pattern 21 remains, when the height of the high convex portion 24 decreases, the height increases inside the inclined sidewall pattern 45b. A part of the convex portion 24 remains (FIG. 3C). Thereby, the fall and disappearance of the sidewall pattern 45b during the process can be prevented more reliably.

(Second Embodiment)
4 and 5 are process diagrams for explaining another embodiment of the pattern forming method of the present invention.
In the present invention, first, the core material pattern 31 is formed on one surface of the workpiece 11 (FIG. 4A). In the illustrated example, the workpiece 11 is such that the hard mask material layer 14 that is the first workpiece is positioned on one surface of the base material 12 that is the second workpiece, and the workpiece in the above-described embodiment. Since it is the same as that of the body 11, description here is abbreviate | omitted.
The core material pattern 31 formed on the hard mask material layer 14 that is the first processed body of the workpiece 11 has a pitch twice as large as the pitch of the first fine pattern to be formed (pitch P1 described later). It has the low convex part 32 for 1st fine pattern formation which has P2, and the high convex part 34 for 2nd fine pattern formation. In the core material pattern 31, the high convex portion 34 is separated from the low convex portion 32, and the width G of the gap between the high convex portion 34 and the adjacent low convex portion 32 is a sidewall material film formed in a later step. It is preferably less than twice the thickness of 41. If the gap width G is twice or more the thickness of the sidewall material film 41, an annular pattern surrounding the second fine pattern is formed between the first fine pattern and the second fine pattern to be formed. Will be. Therefore, when such an annular pattern is not allowed, the interval width G is set to be less than twice the thickness of the sidewall material film 41.

The height H1 and width W1 of the low convex portion 32 constituting the core material pattern 31 and the height H2 and width W2 of the high convex portion 34 are the height and width required for the side wall pattern formed as will be described later. And can be set as appropriate in consideration of the dimension of the second fine pattern and the like. Further, the height H2 of the high convex portion 34 only needs to be larger than the height H1 of the low convex portion 32. In the dry etching of the hard mask material layer 14 which is a first workpiece to be described later, the high convex portion 34 is The height H2 can be set as appropriate so as to function as an etching mask. The material constituting the core material pattern 31 is the same as the material constituting the core material pattern 21 described above, and a description thereof is omitted here. In addition, the core material pattern 31 may be subjected to a slimming process, and then the side wall material film, which is the next process, may be formed as in the core material pattern 21 described above. The formation of the core material pattern 31 will be described later.
Next, a sidewall material film 41 is formed on the hard mask material layer 14 so as to cover the core material pattern 31 (FIG. 4B). In the formation of the sidewall material film 41, the sidewall material film 41 is also formed in the gap between the high convex portion 34 and the adjacent low convex portion 32. The formation of the sidewall material film 41 can be performed in the same manner as the formation of the sidewall material film 41 in the above-described embodiment, and description thereof is omitted here.

Next, the sidewall material film 41 and the core material pattern 31 are etched and etched back to expose the hard mask material layer 14 and leave the sidewall material film 41 on the sidewalls of the core material pattern 31. Thereby, the side wall pattern 45a which consists of the side wall pattern 45a located in the side wall of the low convex part 32 of the core material pattern 31 and the side wall pattern 45b located in the side wall of the high convex part 34 is formed (FIG.4 (C)). The formed sidewall pattern 45b is in contact with the hard mask material layer 14 and is located in the entire sidewall of the high convex portion 34, and is different from the sidewall pattern 45b in the above-described embodiment in this respect. Such etch-back can be performed in the same manner as the etch-back in the above-described embodiment, and description thereof is omitted here.
Next, the low convex portion 32 is removed so that the high convex portion 34 of the core material pattern 31 remains (FIG. 5A). Due to the removal of the low convex portion 32, the corresponding height disappears in the high convex portion 34. Therefore, the height of the high convex portion 24 is lowered so as to leave the side wall pattern 45b located on the side wall of the high convex portion 24. The removal of the low convex portion 32 of the core material pattern 31 can be performed in the same manner as the removal of the low convex portion 22 of the core material pattern 21 in the above-described embodiment, and the description thereof is omitted here.

Next, the hard mask material layer 14 which is the first workpiece is dry-etched using the sidewall pattern 45 and the remaining high protrusions 34 as an etching mask to form the hard mask 15 (FIG. 5B). ). The hard mask 15 thus formed has a first fine pattern forming hard mask 15a located under the side wall pattern 45a, and a second fine pattern forming hard mask 15a located under the high convex portion 34 and the side wall pattern 45b. It consists of a hard mask 15b.
Next, the sidewall pattern 45 is removed, the hard mask 15 is used as an etching mask, the substrate 12 as the second workpiece is dry-etched (FIG. 5C), and then the hard mask 15 is removed (FIG. 5). (D)). Thereby, the 1st fine pattern 13a of the pitch P1 and the 2nd fine pattern 13b with a dimension larger than this 1st fine pattern 13a can be simultaneously formed in the same surface of the base material 12. FIG. Further, by selecting a material suitable for the base material of the imprint mold as described above as the base material 12, the first fine pattern 13a having the pitch P1 on the same surface of the base material 12, and the first fine pattern 13a. An imprint mold provided with the second fine pattern 13b having a larger dimension than that can be manufactured.
In the present invention, ½ (half pitch) of the pitch P1 of the first fine pattern 13a is set to a dimension that makes it difficult or impossible to form a pattern by a lithography method such as an electron beam lithography method or a photolithography method. be able to. In the above example, dry etching of the substrate 12 is performed after the sidewall pattern 45 is removed, but the removal of the sidewall pattern 45 may be performed after the dry etching of the substrate 12.

Such a pattern forming method of the present invention can form a plurality of types of patterns having different pattern densities and dimensions with high accuracy and yield by using a sidewall process. Therefore, a semiconductor device having a plurality of types of patterns having different pattern densities and dimensions can be manufactured with high accuracy and yield.
In the imprint mold manufacturing method of the present invention using the pattern forming method of the present invention, a fine pattern having a dimension that is difficult or impossible to be resolved by an electron beam lithography method can be resolved on a mold substrate. It is possible to simultaneously form a large pattern with various dimensions. Further, the process can be simplified as compared with the conventional imprint mold manufacturing method in which the fine pattern formation and the large pattern formation are performed in separate processes. Thus, an imprint having a concavo-convex structure having a first fine pattern having a dimension that is difficult or impossible to be resolved by an electron beam lithography method and a second fine pattern having a dimension that can be resolved by an electron beam lithography method. The mold can be manufactured with high accuracy and yield.

Furthermore, in the imprint mold manufacturing method using the pattern forming method of the present invention described above, as described later, electron beam lithography can be replaced with imprint lithography, and in this case, an etching mask pattern is formed. The throughput of the lithography process can be improved. Such an imprint mold manufacturing method of the present invention is particularly effective when applied to the manufacture of an imprint mold having a concavo-convex structure in which the yield is poor in the manufacturing method using the conventional side wall process.
In addition, the above-mentioned embodiment is an illustration, The pattern formation method of this invention and the manufacturing method of an imprint mold are not limited to these embodiment. For example, a plurality of types of second fine patterns can be formed. In this case, core material patterns 21 and 31 having high convex portions 24 and 34 corresponding to the second fine pattern to be formed are formed, Pattern formation is performed in the same manner as in the above-described embodiment.

[Imprint mold]
Next, the imprint mold of the present invention will be described.
The imprint mold of the present invention is a pattern forming method for simultaneously forming a first fine pattern and a second fine pattern having a size larger than the first fine pattern on the same surface, and an imprint mold used for the imprint mold manufacturing method. It is a print mold.
6 is a schematic cross-sectional view showing an embodiment of the imprint mold of the present invention, and FIG. 7 is a partially enlarged cross-sectional view of the imprint mold shown in FIG. 6 and 7, the imprint mold 61 includes a base material 62, a concavo-convex structure region A set on one surface 62a of the base material, and a concavo-convex structure 63 positioned in the concavo-convex structure region A. ing. The concavo-convex structure 63 has a first recess 64 having a pitch P2 that is twice the pitch of the first fine pattern to be formed, and an opening corresponding to the second fine pattern. A deep second recess 66, and the second recess 66 is continuous with the adjacent first recess 64. In FIG. 6, as the first concave portion 64 and the second concave portion 66 included in the concavo-convex structure 63, concave portions having the same dimensions are illustrated for convenience.

When the resist used for imprinting using the imprint mold 61 is photocurable, the material of the base material 62 constituting the imprint mold 61 is a material that can transmit irradiation light for curing these. For example, in addition to glass such as quartz glass, silicate glass, calcium fluoride, magnesium fluoride, and acrylic glass, sapphire and gallium nitride, and resins such as polycarbonate, polystyrene, acrylic, and polypropylene, or Any of these laminated materials can be used. Further, when the resist to be used is not photocurable, or when light for curing the resist can be irradiated from the workpiece to be patterned, the base material 62 does not have optical transparency. In addition to the above materials, for example, metals such as silicon, nickel, titanium, and aluminum, alloys thereof, oxides, nitrides, or any laminated material thereof can be used.
The thickness of the base material 62 of the imprint mold 61 can be set in consideration of the shape of the mold, the strength of the material, suitability for handling, and the like, and can be set as appropriate within a range of about 300 μm to 10 mm, for example. Further, the base material 62 may have a so-called mesa structure in which the surface on which the concavo-convex structure region A is set has a convex structure of one step or two steps or more with respect to the surrounding region.

As described later, such an imprint mold 61 is used for imprinting in which a core material pattern is formed on one surface of a workpiece in the pattern forming method and the imprint mold manufacturing method of the present invention. is there. Therefore, the depth D1 and width W′1 of the first recess 64 and the depth D2 and width W′2 of the second recess 66 are the height and width of the low protrusion of the core material pattern to be formed. And it can be appropriately set in consideration of the height and width of the high convex portion. The depth D2 of the second recess 66 is preferably at least twice the depth D1 of the first recess 64. When the depth D2 of the second recess 66 is less than twice the depth D1 of the first recess 64, the pattern forming method and imprint mold of the present invention for forming the core material pattern using the imprint mold 61 In this manufacturing method, the sidewall pattern collapses and disappears during the pattern formation process, which is not preferable.
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern, the depth D1 and the width W′1 of the first recess 64 of the imprint mold 61 are performed. The depth D2 and the width W′2 of the second recess 66 can be appropriately set in consideration of the dimension after slimming, the slimming conditions, and the like.

In the example shown in FIG. 7, the wall surface of the second recess 66 of the imprint mold 61 is formed perpendicular to the one surface 62a of the base material 62, but as shown in FIG. The wall surface near the bottom of 66 may be inclined with respect to one surface 62 a of the base material 62. In addition, only the wall surface near the bottom of the second recess 66 may be inclined.
FIG. 9 is a partially enlarged sectional view corresponding to FIG. 7 showing another embodiment of the imprint mold of the present invention. In FIG. 9, the imprint mold 61 ′ includes a base material 62, a concavo-convex structure region A set on one surface 62 a of the base material, and a concavo-convex structure 63 positioned in the concavo-convex structure region A. . The concavo-convex structure 63 has a first recess 64 having a pitch P2 that is twice the pitch of the first fine pattern to be formed, and an opening corresponding to the second fine pattern. A deep second recess 66. A partition wall 65 is located between the second recess 66 and the first recess 64, and the second recess 66 is separated from the first recess 64.

The depth D1 and width W′1 of the first recess 64 of the imprint mold 61 ′ and the depth D2 and width W′2 of the second recess 66 are the height of the low protrusion of the core material pattern to be formed. The width and width and the height and width of the high protrusion can be set as appropriate. Further, the depth D2 of the second recess 66 may be larger than the depth D1 of the first recess 64, and the imprint mold 61 ′ is used in the pattern forming method and the imprint mold manufacturing method of the present invention described above. In this case, the depth D2 of the second concave portion 66 can be appropriately set so that the high convex portion of the core material pattern to be formed has a height that can function as an etching mask. The width G ′ of the partition wall 65 determines the width G (see FIG. 4A) between the high convex portion 34 and the adjacent low convex portion 32 in the core material pattern to be formed.
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern, the depth D1 and the width W ′ of the first concave portion 64 of the imprint mold 61 ′. 1. The depth D2 and width W′2 of the second recess 66 and the width G ′ of the partition wall 65 can be appropriately set in consideration of the dimension after slimming, slimming conditions, and the like.
The above-described embodiments are exemplifications, and the imprint mold of the present invention is not limited to these embodiments. For example, it may have a plurality of types of second recesses, and in this case, the depth of the second recesses is the same, and according to the second fine pattern for forming the opening shape and opening area. Can do.

<About the formation of the core material pattern>
Next, the formation of the core material pattern in the pattern forming method and the imprint mold manufacturing method of the present invention described above will be described.
Examples of the formation of the core material pattern include [1] to [4] exemplified below.
(Formation of core material pattern [1])
First, formation of the core material pattern using the above-described imprint mold of the present invention will be described.
FIG. 10 is a process diagram for explaining an example of forming the core material pattern 21 in the above-described pattern forming method and imprint mold manufacturing method of the present invention using the above-described imprint mold 61 of the present invention. is there. In forming the core material pattern 21, the curable resist 20 is supplied to one surface of the workpiece 11, the imprint mold 61 and the workpiece 11 are brought close to each other, and the imprint mold 61 and the workpiece are formed. The resist 20 is developed between the two (FIG. 10A).

In the illustrated example, the workpiece 11 is such that the hard mask material layer 14 as the first workpiece is positioned on one surface of the substrate 12 as the second workpiece, and the curable resist 20 is hardened. It is supplied on the mask material layer 14. Such a workpiece 11 is the same as the workpiece 11 described in the above-described pattern forming method and imprint mold manufacturing method of the present invention, and a description thereof is omitted here.
As the resist 20, a known photo-curing resist or a thermosetting resist can be used. Such a resist 20 can be supplied as a droplet to a desired part of the workpiece 11 from an inkjet head, for example. Further, the resist 20 may be supplied onto the workpiece 11 by spin coating.
Next, the resist 20 is cured to form a precursor core material pattern 20 ′, and then the imprint mold 61 is separated (FIG. 10B), and a remaining film located between the convex portions of the precursor core material pattern 20 ′ is formed. By removing, the core material pattern 21 is formed on the workpiece 11 (FIG. 10C).
Further, by using the imprint mold 61 shown in FIG. 8 to form the core material pattern in the same manner as described above, the pattern forming method of the present invention described above and the imprint mold manufacturing method shown in FIG. A core material pattern 21 'as shown in FIG.

FIG. 11 is a process diagram for explaining an example of forming the core material pattern 31 in the above-described pattern forming method and imprint mold manufacturing method of the present invention using the above-described imprint mold 61 ′ of the present invention. It is. Also in the formation of the core material pattern 31, the curable resist 30 is supplied to one surface of the workpiece 11, the imprint mold 61 ′ and the workpiece 11 are brought close to each other, and the imprint mold 61 ′ A resist 30 is developed between the workpiece 11 (FIG. 11A). The supply of the resist 30 can be the same as the supply of the resist 20 described above.
Next, the resist 30 is cured to form a precursor core material pattern 30 ′, and then the imprint mold 61 ′ is separated (FIG. 11B), and the remaining film located between the convex portions of the precursor core material pattern 30 ′. Is removed to form the core material pattern 31 on the workpiece 11 (FIG. 11C).
Thus, by using the imprint mold of the present invention, a core material pattern having a low convex portion and a high convex portion having different heights can be formed by one imprint, and the core to be formed The shape and dimensions of the material pattern are high accuracy reflecting the accuracy of the imprint mold to be used, and the pattern forming method and the imprint mold manufacturing method of the present invention can be easily and reliably performed. .

(Core pattern formation [2])
FIG. 12 is a process diagram for explaining another example of forming the core material pattern 21 in the pattern forming method and the imprint mold manufacturing method of the present invention described above.
In this example, first, an electron beam sensitive or light sensitive resist is applied to one surface of the workpiece 11, and then, the base of the low convex portion 22 and the high convex portion is formed by an electron beam lithography method or a photolithography method. A resist pattern to be 22 ″ is formed (FIG. 12A). The base portion 22 ″ of the high convex portion thus formed is continuous with some of the low convex portions 22, and in the illustrated example, The boundary is indicated by a chain line for convenience.
In the illustrated example, the workpiece 11 is such that the hard mask material layer 14 as the first processed body is positioned on one surface of the base material 12 as the second processed body, and the low convex portion 22 and the high convex portion. A resist pattern to be a base 22 ″ of the portion is formed on the hard mask material layer 14. Such a workpiece 11 is processed by the pattern forming method and the imprint mold manufacturing method described above. Since it is the same as that of the body 11, description here is abbreviate | omitted.

Next, an electron beam sensitive or light sensitive resist is applied so as to cover the low convex portion 22 and the high convex base portion 22 ″, and then the high convex base portion 22 is formed by an electron beam lithography method or a photolithography method. A resist pattern 24 'is formed on "" (FIG. 12B). Thereby, the core material pattern 21 can be formed on the to-be-processed body 11 (FIG.12 (C)).
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern 21, the low convex portion 22 and the high convex portion base 22 formed as described above. ″ And the dimension of the resist pattern 24 ′ can be appropriately set in consideration of the dimension after slimming, slimming conditions, and the like.
Further, in the electron beam lithography method or the photolithography method for forming the resist pattern 24 ', the bottom portion 24 is obtained by giving gradation to electron beam irradiation or light irradiation, or by adjusting development conditions. A resist pattern 24 ′ having a slope on the side surface 24 ′ c such that the upper portion 24 ′ a becomes smaller than ‘b’ may be formed (FIG. 13A). Thereby, it is possible to form the core material pattern 21 ′ as shown in FIG. 3A mentioned in the pattern forming method and the imprint mold manufacturing method of the present invention (FIG. 13B).

FIG. 14 is a process diagram for explaining another example of forming the core material pattern 31 in the pattern forming method and the imprint mold manufacturing method of the present invention described above.
In this example, first, an electron beam sensitive or light sensitive resist is applied to the hard mask material layer 14 which is the first processed body of the workpiece 11, and then the low convexity is formed by the electron beam lithography method or the photolithography method. A resist pattern is formed to be the portion 32 and the base portion 32 ″ of the high convex portion (FIG. 14A). Here, the base portion 32 ″ of the high convex portion is formed so as to be separated from the low convex portion 32, and the base portion 32 is formed. The width G of the gap between ″ and the adjacent low protrusion 32 is the same as the width G of the gap between the high protrusion 34 and the adjacent low protrusion 32 in the core material pattern 31 described above.

Next, an electron beam sensitive or light sensitive resist is applied so as to cover the low convex portion 32 and the high convex base portion 32 ″, and then the high convex base portion 32 is formed by an electron beam lithography method or a photolithography method. A resist pattern 34 'is formed on "" (FIG. 14B). Thereby, the core material pattern 31 can be formed on the workpiece 11 (FIG. 14C).
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern 31, the low convex portion 32 and the high convex base portion 32 formed as described above. The dimension of "", the dimension of the resist pattern 34 ', and the width of the gap between the base 32 "and the adjacent low convex part 32 can be appropriately set in consideration of the dimension after slimming, slimming conditions, and the like.

(Core pattern formation [3])
FIG. 15 is a process diagram for explaining another example of forming the core material pattern 21 in the pattern forming method and the imprint mold manufacturing method of the present invention described above.
In this example, first, the concave portions 104 formed at the pitch P <b> 2 corresponding to the low convex portions 22 and the concave portions 104 ′ corresponding to the same height as the low convex portions 22 of the high convex portions 24 are formed on the base material 102. The imprint mold 101 provided with the concavo-convex structure 103 including is prepared (FIG. 15A). The base material 102 of the imprint mold 101 can be the same as the base material constituting the above-described imprint mold of the present invention.
Next, a curable resist 20 is supplied to one surface of the workpiece 11, the imprint mold 101 and the workpiece 11 are brought close to each other, and the resist is placed between the imprint mold 101 and the workpiece 11. 20 is expanded (FIG. 15B).

In the illustrated example, the workpiece 11 is such that the hard mask material layer 14 as the first workpiece is positioned on one surface of the substrate 12 as the second workpiece, and the curable resist 20 is hardened. It is supplied on the mask material layer 14. Such a workpiece 11 is the same as the workpiece 11 described in the above-described pattern forming method and imprint mold manufacturing method of the present invention, and a description thereof is omitted here.
As the resist 20, a known photo-curing resist or a thermosetting resist can be used. Such a resist 20 can be supplied as a droplet to a desired part of the workpiece 11 from an inkjet head, for example. Further, the resist 20 may be supplied onto the workpiece 11 by spin coating.
Next, the resist 20 is cured, the imprint mold 101 is separated, and the remaining film located between the convex portions corresponding to the concave portion 104 and the concave portion 104 ′ is removed. The base 22 ″ of the portion is formed (FIG. 15C). The base 22 ″ of the high convex portion thus formed is continuous with some of the low convex portions 22, and in the illustrated example, the boundary between the two Is indicated by a chain line for convenience.
Next, an electron beam sensitive or light sensitive resist is applied so as to cover the low convex portion 22 and the high convex base portion 22 ″, and then the high convex base portion 22 is formed by an electron beam lithography method or a photolithography method. A resist pattern 24 'is formed on "" (FIG. 15D). Thereby, the core material pattern 21 can be formed on the workpiece 11.

When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern 21, the low convex portion 22 and the high convex portion base 22 formed as described above. ″ And the dimension of the resist pattern 24 ′ can be appropriately set in consideration of the dimension after slimming, slimming conditions, and the like.
Further, in the electron beam lithography method or the photolithography method for forming the resist pattern 24 ', the bottom portion 24 is obtained by giving gradation to electron beam irradiation or light irradiation, or by adjusting development conditions. A resist pattern 24 ′ having a slope on the side surface 24 ′ c so that the upper portion 24 ′ a becomes smaller than ‘b’ may be formed (see FIG. 13A). Thereby, the core material pattern 21 ′ as shown in FIG. 3A mentioned in the pattern forming method of the present invention and the imprint mold manufacturing method can be formed (see FIG. 13B). .

FIG. 16 is a process diagram for explaining another example of forming the core material pattern 31 in the pattern forming method and the imprint mold manufacturing method of the present invention described above.
In this example, first, the concave portions 104 formed at the pitch P <b> 2 corresponding to the low convex portions 22 and the concave portions 104 ′ corresponding to the same height as the low convex portions 22 of the high convex portions 24 are formed on the base material 102. Then, an imprint mold 101 ′ having a concavo-convex structure 103 having a partition wall portion 105 located between the concave portion 104 ′ and the adjacent concave portion 104 is prepared (FIG. 16A). The width G ′ of the partition wall portion 105 determines the width G (see FIG. 4A) between the high convex portion 34 and the adjacent low convex portion 32 in the core material pattern to be formed. The base material 102 of the imprint mold 101 ′ can be the same as the base material constituting the above-described imprint mold of the present invention.
Next, a curable resist 30 is supplied to one surface of the workpiece 11, the imprint mold 101 ′ and the workpiece 11 are brought close to each other, and between the imprint mold 101 ′ and the workpiece 11. Then, the resist 30 is developed (FIG. 16B).
Next, the resist 30 is cured, the imprint mold 101 ′ is separated, and the remaining film located between the concave portions 104 and the convex portions corresponding to the concave portions 104 ′ is removed. A convex base 32 ″ is formed (FIG. 16C).

Next, an electron beam sensitive or light sensitive resist is applied so as to cover the low convex portion 32 and the high convex base portion 32 ″, and then the high convex base portion 32 is formed by an electron beam lithography method or a photolithography method. A resist pattern 34 'is formed on "" (FIG. 16D). Thereby, the core material pattern 31 can be formed on the workpiece 11.
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern 31, the low convex portion 32 and the high convex base portion 32 formed as described above. The dimension of "", the width of the gap between the base 32 "and the adjacent low convex part 32, and the dimension of the resist pattern 34 'can be appropriately set in consideration of the dimension after slimming, slimming conditions, and the like.

(Formation of core material pattern [4])
FIG. 17 is a process diagram for explaining another example of forming the core material pattern 21 in the pattern forming method and the imprint mold manufacturing method of the present invention described above.
In this example, first, the first thin film 20a is formed on one surface of the workpiece 11 by using the first material for the core material pattern, and the first material for the core material pattern is different in etching resistance from the first material. A second thin film 20b is formed on the first thin film 20a by using the second material, and an electron beam sensitive or light sensitive resist is applied on the second thin film 20b. Thereafter, an electron beam lithography method or photolithography is applied. A first etching mask 25a is formed by the method (FIG. 17A).
In the illustrated example, the workpiece 11 is such that the hard mask material layer 14 as the first workpiece is located on one surface of the base material 12 as the second workpiece, and the workpiece 11 is on the hard mask material layer 14. The first thin film 20a and the second thin film 20b are stacked in this order. Such a workpiece 11 is the same as the workpiece 11 described in the above-described pattern forming method and imprint mold manufacturing method of the present invention, and a description thereof is omitted here.

As the first material and the second material for the core material pattern, materials other than the curable resist used in the formation of the core material pattern [1] to [3] can be used. Examples thereof include silicon compounds such as polysilicon, silicon oxide, silicon nitride, and silicon carbide. The processability of the first material and the second material, the ability to remove the core material pattern, and the etching selectivity with the hard mask material layer 14 It can be selected as appropriate in consideration of the above. The processability of the first material and the second material can be obtained by using materials having different etching resistances. For example, silicon nitride can be used as the first material and silicon oxide can be used as the second material.
Next, the second thin film 20b is dry-etched through the first etching mask 25a to form an upper pattern 24 ′ having a high convex portion on the first thin film 20a (FIG. 17B). In dry etching the second thin film 20b, the first thin film 20a functions as an etching stopper.
Next, an electron beam sensitive or light sensitive resist is applied so as to cover the upper pattern 24 'and the first thin film 20a, and then a second etching mask 25b is formed by electron beam lithography or photolithography. (FIG. 17C).

Next, the first thin film 20a is dry-etched through the second etching mask 25b to form the low convex portion 22, and the high convex base portion 22 ″ is formed so as to be integrated with the upper pattern 24 ′. The core material pattern 21 can be formed by forming the portion 24 (FIG. 17D) The base portion 22 ″ of the high convex portion thus formed is continuous with some of the low convex portions 22. In the illustrated example, the boundary between the two is indicated by a chain line for convenience.
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern 21, the low convex portion 22 and the high convex portion base 22 formed as described above. ″ And the dimension of the second thin film pattern 24 ′ can be appropriately set in consideration of the dimension after slimming, slimming conditions, and the like.
In addition, in the electron beam lithography method or the photolithography method for forming the second etching mask 25b described above, the electron beam irradiation or the light irradiation has gradation, or the development conditions are adjusted to adjust the first etching mask 25b. 2. By reducing the thickness of the peripheral edge of the etching mask 25b, the second thin film pattern 24 'is inclined on the side surface 24'c so that the upper part 24'a is smaller than the bottom part 24'b. (See FIG. 13A). Thereby, the core material pattern 21 ′ as shown in FIG. 3A mentioned in the pattern forming method of the present invention and the imprint mold manufacturing method can be formed (see FIG. 13B). .

FIG. 18 is a process diagram for explaining another example of forming the core material pattern 31 in the pattern forming method and the imprint mold manufacturing method of the present invention described above.
In this example, first, the first thin film 30a is formed on one surface of the workpiece 11 using the first material for the core material pattern, and the first thin film 30a has a different etching resistance from the first material. A second thin film 30b is formed on the first thin film 30a using a second material, and an electron beam sensitive or light sensitive resist is applied on the second thin film 30b, and then an electron beam lithography method or photolithography is applied. A first etching mask 35a is formed by the method (FIG. 17A).
The first material and the second material for the core material pattern can be the same as the first material and the second material in the formation of the core material pattern described with reference to FIG.
Next, the second thin film 30b is dry-etched through the first etching mask 35a to form an upper pattern 34 'having a high convex portion on the first thin film 30a (FIG. 18B). In dry etching the second thin film 30b, the first thin film 30a functions as an etching stopper.

Next, an electron beam sensitive or light sensitive resist is applied so as to cover the upper pattern 34 'and the first thin film 30a, and then a second etching mask 35b is formed by an electron beam lithography method or a photolithography method. (FIG. 18C).
Next, the first thin film 30a is dry-etched through the second etching mask 35b to form the low convex portion 32, and the high convex base portion 32 ″ is formed so as to be integrated with the upper pattern 34 ′. The core pattern 31 can be formed by forming the portion 34 (FIG. 18D). Here, the base portion 32 ″ of the high convex portion is formed so as to be separated from the low convex portion 32, and the base portion 32 ″ is formed. The width G of the gap between the adjacent low convex portions 32 is the same as the width G of the gap between the high convex portion 34 and the adjacent low convex portion 32 in the core material pattern 31 described above.
When the slimming process described in the explanation of the pattern forming method and the imprint mold manufacturing method of the present invention is applied to the core material pattern 31, the low convex portion 32 and the high convex base portion 32 formed as described above. The dimension of ″, the width G of the gap between the base 32 ″ and the adjacent low protrusion 32, and the dimension of the second thin film pattern 34 ′ should be set appropriately in consideration of the dimension after slimming, slimming conditions, etc. Can do.

  In the description of the pattern forming method and the imprint mold manufacturing method of the present invention described above, the hard mask material layer 14 as the first processed body is formed on one surface of the substrate 12 as the second processed body as the processed body. After the hard mask material layer 14 is dry-etched to form a hard mask, the substrate 12 is etched through the hard mask to form the first fine pattern 13a and the second fine pattern 13a. Although the fine pattern 13b is formed, the workpiece and pattern formation used in the present invention are not limited to the above-described embodiments. For example, the workpiece 11 consisting only of the substrate 12 is used as the workpiece, and the first fine pattern 13a and the first fine pattern 13a are directly formed on the substrate 12 without performing hard mask formation by dry etching of the hard mask material layer 14. A second fine pattern 13b (see FIG. 2D) having a size larger than that of the first fine pattern 13a may be formed.

Further, as shown in FIG. 19, a processed layer 14 </ b> A as a second processed body and a hard mask material layer 14 </ b> B as a first processed body were laminated on one surface of the base material 12 as the processed body. Using the workpiece 11 ′, the core material pattern 21 is formed on the hard mask material layer 14B which is the first workpiece of the workpiece 11 ′ by the pattern forming method of the present invention (FIG. 19A). Thereafter, a sidewall material film is formed so as to cover the core material pattern 21, the sidewall material film and the core material pattern are subjected to etching treatment, and a sidewall pattern made of the sidewall material film is formed on the sidewall of the remaining core material pattern Then, the low convex portion 22 is removed so that the high convex portion 24 of the core material pattern 21 remains, and the sidewall pattern 45 (45a, 45b) and the remaining high convex portion 24 are etched. FIG. 19 ( )), The hard mask material layer 14B is dry-etched to form a hard mask 15 comprising a hard mask 15a for forming a first fine pattern and a hard mask 15b for forming a second fine pattern having a size larger than the first fine pattern. After that, the processed layer 14A as the second processed body is dry-etched using the hard mask 15 as an etching mask, and the first fine pattern 13a and the first fine pattern 13a are formed. Alternatively, the second fine pattern 13b having a larger dimension may be formed at the same time (FIG. 19D). As the base material 12 of the workpiece 11 ′ and the workpiece layer 14A as the second workpiece, for example, a combination of a base substrate and a functional layer can be used.
Even when such a workpiece 11 ′ is used, the pattern forming method and the imprint mold manufacturing method of the present invention can be achieved by forming the core material patterns 21 ′ and 31 as described above on the workpiece 11 ′. Can be implemented.

  The present invention can be applied to various manufacturing fields in which pattern formation with a dimension smaller than the minimum dimension that can be patterned by the lithography method is required.

DESCRIPTION OF SYMBOLS 11, 11 '... Workpiece 21, 21', 31 ... Core material pattern 22, 32 ... Low convex part 24, 34 ... High convex part 41 ... Side wall material film 45, 45a, 45b ... Side wall pattern 13a ... 1st fine Pattern 13b ... 2nd fine pattern 61, 61 '... Imprint mold 62 ... Base material 63 ... Uneven structure 64 ... 1st recessed part 66 ... 2nd recessed part

In order to achieve such an object, the imprint mold of the present invention is a pattern forming method in which a first fine pattern and a second fine pattern having a dimension larger than the first fine pattern are simultaneously formed on the same surface. A core material pattern having a low convex portion for forming a first fine pattern having a pitch twice as large as a pitch of the first fine pattern and a high convex portion for forming the second fine pattern. Forming on one surface of the workpiece, forming a sidewall material film so as to cover at least the core material pattern, etching the sidewall material film and the core material pattern, and remaining the core material A sidewall pattern made of the sidewall material film is formed on a sidewall of the pattern, and the low protrusion is removed so that the high protrusion of the core material pattern remains, and the sidewall pattern and the remaining In imprint mold that uses the high protrusion and the pattern formation method by etching the workpiece as an etching mask to form a second fine pattern and the first fine pattern, a base material, the group A concavo-convex structure region set on one surface of the material, and a concavo-convex structure located in the concavo-convex structure region, wherein the concavo-convex structure has a pitch twice as large as a pitch of the first fine pattern. A first concave portion corresponding to the low convex portion for forming the first fine pattern and a second concave portion having an opening corresponding to the high convex portion for forming the second fine pattern, The depth is deeper than the first recess, and the opening of the first recess and the opening of the second recess are located on the same plane .

Another aspect of the present invention, the between the first recess and the second recess, the partition wall portion that separates the second recess and the first recess is the to have so that arrangement positions.

Claims (1)

In a pattern forming method for simultaneously forming a first fine pattern and a second fine pattern having a size larger than the first fine pattern on the same surface,
A core material pattern having a low convex portion for forming a first fine pattern having a pitch twice as large as the pitch of the first fine pattern and a high convex portion for forming the second fine pattern is formed on a workpiece. Formed on one side,
Forming a sidewall material film so as to cover at least the core material pattern;
Etching is performed on the sidewall material film and the core material pattern, and a sidewall pattern made of the sidewall material film is formed on the sidewall of the remaining core material pattern,
Removing the low convex portion so that the high convex portion of the core material pattern remains,
The pattern forming method, wherein the workpiece is etched using the sidewall pattern and the remaining high convex portion as an etching mask to form the first fine pattern and the second fine pattern.

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