JP2015115524A - Method of manufacturing imprint mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an imprint mold capable of more improving etching durability of a resin pattern and sufficiently satisfying further request of subdivision and having high dimensional uniformity and an uneven pattern having low defect density.SOLUTION: A method of manufacturing an imprint mold includes the steps of: forming a resin pattern 31 on a main surface 11 of a base material 10 to be processed; irradiating the resin pattern 31 with ionization radiation; and etching the base material 10 to be processed using the resin pattern 31 irradiated with the ionization radiation as a mask. A resin composition constituting the resin pattern 31 includes a polymer having a halogen atom in the constitutional unit.

Description

  The present invention relates to a mold manufacturing method used in an imprint method for forming a fine uneven pattern.

  Nanoimprint technology as a microfabrication technology uses a mold member (imprint mold) in which a fine concavo-convex pattern is formed on the surface of a substrate, and transfers the fine concavo-convex pattern onto a workpiece such as an imprint resin. This is a pattern formation technique for transferring a fine concavo-convex pattern at an equal magnification (see Patent Document 1). In particular, with the progress of further miniaturization of wiring patterns and the like in semiconductor devices, nanoimprint technology is gaining more and more attention in semiconductor device manufacturing processes and the like.

  In the imprint mold used in the nanoimprint technique, a concavo-convex pattern with a finer dimension is required in accordance with the progress of the miniaturization of dimensions in a semiconductor device. Such an imprint mold is generally manufactured as follows.

  First, a blank having a hard mask material film (for example, a chromium compound film) formed on the main surface of an imprint mold substrate (for example, a quartz substrate) is prepared, and the blanks on the hard mask material film of the blank is prepared. Etching is performed using the formed resist pattern as a mask to form a hard mask pattern having a dimension corresponding to the dimension of the fine concavo-convex pattern. Thereafter, an etching process using the hard mask pattern as a mask is performed to form a fine uneven pattern on the main surface of the substrate for imprint mold.

  The resist pattern needs to be formed with a dimension according to the dimension of the hard mask pattern, that is, a dimension according to the dimension of the fine uneven pattern of the imprint mold. On the other hand, since the resist pattern must not disappear during the etching process of the hard mask material film, the resist material constituting the resist pattern has excellent etching resistance under the conditions of the hard mask material film etching process. It is required to be.

  However, even a resist pattern composed of a resist material having excellent etching resistance tends to have a relatively high resist pattern height and an increased aspect ratio as its dimensions are miniaturized. is there. When the aspect ratio becomes large in this way, problems such as the resist pattern falling down and the uneven pattern dimension becoming non-uniform are likely to occur. In particular, in imprint molds used to fabricate semiconductor devices, the requirements for dimensional uniformity and defect density of the concavo-convex pattern are severe, so that the aspect ratio of the resist pattern can be reduced as much as possible. The proposal of the resist material which is excellent in tolerance, and the method of improving the etching tolerance of a resist pattern are earnestly desired.

  In such a background, conventionally, a resist layer having a concavo-convex pattern formed by heating or irradiating with UV light is irradiated with ionizing radiation or far ultraviolet light, and at least the outermost surface carbon of the resist layer is irradiated. -A method of modifying the surface of a resist pattern by increasing the carbon bond density has been proposed (see Patent Document 2).

US Pat. No. 5,722,905 Japanese Patent No. 5052968

  In the above-mentioned Patent Document 2, by irradiating a resist layer having a concavo-convex pattern with ionizing radiation or far ultraviolet light, the carbon-carbon bond density of at least the outermost surface of the resist layer is increased. It is disclosed that the etching resistance can be improved.

  As a resist material constituting the resist layer disclosed in Patent Document 2, a resist material generally used in imprint technology is exemplified, but the surface modification method disclosed in Patent Document 2 Therefore, the effect of improving the dry etching resistance when these resist materials are used has a problem that it is difficult to obtain the dry etching resistance that can sufficiently satisfy the demand for further miniaturization.

  In view of such problems, the present invention can further improve the etching resistance of the resin pattern, can sufficiently satisfy the demand for further miniaturization, has high dimensional uniformity, and has a low defect density. It aims at providing the manufacturing method of the imprint mold which has a pattern.

  In order to solve the above problems, the present invention provides a pattern forming step of forming a resin pattern on a main surface of a substrate to be processed, an ionizing radiation irradiation step of irradiating the resin pattern with ionizing radiation, and the ionizing radiation. A substrate etching step of etching the substrate to be processed using the resin pattern irradiated with a mask as a mask, and the resin composition constituting the resin pattern contains a polymer having a halogen atom in a structural unit An imprint mold manufacturing method is provided (Invention 1).

  According to the said invention (invention 1), the resin composition which comprises a resin pattern contains the polymer which has a halogen atom in a structural unit, and ionizing radiation is given with respect to the resin pattern comprised by the said resin composition. Irradiation can make the etching resistance of the resin pattern extremely excellent. As a result, it is possible to manufacture an imprint mold with high dimensional uniformity and low defect density that can sufficiently satisfy the demand for further miniaturization of the concavo-convex pattern.

  In the present invention, the resin pattern may be directly formed on the main surface of the substrate to be processed, or may be formed on a hard mask layer or the like provided on the main surface of the substrate to be processed. Good. In the latter case, the hard mask layer is etched using the resin pattern irradiated with ionizing radiation as a mask to form a hard mask pattern, and the substrate to be processed can be etched using the hard mask pattern as a mask.

  The reason why the etching resistance of the resin pattern is improved in the above invention (Invention 1) is considered as follows.

  In general, a resin pattern is etched by an etching action of an etchant (etching gas) that has penetrated inside the resin pattern surface in addition to an etching action on the surface of the resin pattern by an etchant (etching gas). Since the resin composition contains a polymer having a halogen atom in the structural unit, the bond between the halogen atom and the carbon atom is broken by the irradiation of ionizing radiation to the resin pattern, and the halogen atom is desorbed. . Thereby, the free volume of the resin pattern decreases. As a result, it is presumed that the etchant (etching gas) does not easily enter the resin pattern and the etching resistance is improved.

  In the said invention (invention 1), it is preferable that the said resin composition contains the polymer which has a structural unit shown to following formula (I) (invention 2).

（式（Ｉ）中、Ｒ₁は、水素原子又は炭素数１〜４の炭化水素基若しくは置換可アルキル基を表し、Ｒ₂は、炭素数１〜４の炭化水素基又は置換可アルキル基を表し、Ｘはハロゲン原子を表す。）

(In the formula (I), R ₁ represents a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group, and R ₂ represents a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group. X represents a halogen atom.)

  According to the said invention (invention 2), it has a halogen group and a carbonyl group (ester group) in the side chain of the structural unit shown by said formula (I), Therefore A halogen atom is easy to detach | leave and it is easy to produce a radical. Depolymerization of the polymer is likely to occur. As a result, the free volume of the resin pattern is further reduced, and the etching resistance can be further improved.

In the above invention (invention 2), wherein in formula (I), is preferably R ₁ is a hydrocarbon group having 1 to 4 carbon atoms (invention 3), and more preferably R ₁ is a methyl group ( Invention 4). In the above invention (invention 2 to 4), wherein in formula (I), is preferably R ₂ is a hydrocarbon group having 1 to 4 carbon atoms (Invention 5), the R ₂ is a methyl group Is more preferable (Invention 6).

  In the said invention (invention 1-6), the said pattern formation process irradiates an active energy ray to the resin layer comprised by the said resin composition formed on the main surface of the said workpiece, and patterns It may include a step of forming a latent image and a step of developing the resin layer on which the pattern latent image is formed (Invention 7), and may be formed on the main surface of the workpiece. An imprint material is supplied onto a resin layer composed of the resin composition, and a mask pattern composed of the imprint material is formed using an imprint mold having an uneven pattern corresponding to the resin pattern. Including an imprint process and a resin layer etching process for etching the resin layer using a mask pattern formed of the imprint material as a mask. Even better (invention 8).

  According to the present invention, the imprint mold having a concavo-convex pattern that can further improve the etching resistance of the resin pattern, can sufficiently satisfy the demand for further miniaturization, has high dimensional uniformity, and low defect density. The manufacturing method of can be provided.

FIG. 1 is a process flow diagram showing the respective steps of a method for manufacturing an imprint mold according to an embodiment of the present invention in cross-sectional views. FIG. 2 is a process flow diagram showing each step of the method of forming a resin pattern by imprint lithography in a cross-sectional view in one embodiment of the present invention. FIG. 3 is a cross-sectional view showing a schematic configuration of an imprint mold that can be used to form a resist pattern in an embodiment of the present invention. FIG. 4 is a diagram showing the results of IR spectrum measurement in Experimental Example 1.

  Hereinafter, an imprint mold manufacturing method according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a process flow diagram showing the steps of an imprint mold manufacturing method according to an embodiment of the present invention in cross-sectional views, and FIG. It is a process flowchart which shows each process of the method of forming a pattern with sectional drawing.

  As shown in FIG. 1A, in the imprint mold manufacturing method according to this embodiment, a hard mask layer 20 is formed on the main surface 11, and a resin layer 30 is formed on the hard mask layer 20. An imprint mold substrate 10 is prepared.

  As the base material 10 for imprint molds, according to the uses (uses for optical imprinting, thermal imprinting, etc.) of the imprint mold 1 manufactured in the first embodiment (see FIG. 1G). A substrate that can be selected as appropriate and is generally used in manufacturing an imprint mold (for example, quartz glass, soda glass, fluorite, calcium fluoride substrate, magnesium fluoride substrate, acrylic glass, etc. Glass substrate, polycarbonate substrate, polypropylene substrate, resin substrate such as polyethylene substrate, transparent substrate such as laminated substrate obtained by laminating two or more substrates arbitrarily selected from these; nickel substrate, titanium substrate, aluminum substrate, etc. A metal substrate; a semiconductor substrate such as a silicon substrate or a gallium nitride substrate) can be used. The thickness of the imprint mold base material 10 can be appropriately set in the range of, for example, about 300 μm to 10 mm in consideration of the strength of the substrate, handling suitability and the like. In the first embodiment, “transparent” means that the transmittance of light having a wavelength of 300 to 450 nm is 85% or more, preferably 90% or more, and particularly preferably 95% or more.

  Examples of the material constituting the hard mask layer 20 include metals such as chromium, titanium, tantalum, silicon, and aluminum; chromium-based compounds such as chromium nitride, chromium oxide, and chromium oxynitride; tantalum oxide, tantalum oxynitride, and boron oxide. A tantalum compound such as tantalum tantalum or tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride, or the like can be used alone or in combination of two or more selected arbitrarily.

  The hard mask layer 20 is used as a mask when the imprint mold substrate 10 is etched after being patterned in a hard mask pattern forming step (see FIG. 1F) described later. Therefore, it is preferable to select the constituent material of the hard mask layer 20 in consideration of the etching selection ratio and the like according to the type of the imprint mold substrate 10. For example, when the imprint mold substrate 10 is a quartz glass substrate, a metal chromium film or the like can be suitably selected as the hard mask layer 20.

  The thickness of the hard mask layer 20 is appropriately set in consideration of the etching selection ratio according to the type of the imprint mold substrate 10, the aspect ratio of the fine uneven pattern 2 in the imprint mold 1, and the like. For example, when the imprint mold substrate 10 is quartz glass and the hard mask layer 20 is a metal chromium film, the thickness of the hard mask layer 20 is about 3 to 10 nm.

  The resin layer 30 formed on the hard mask layer 20 is made of a predetermined positive resin composition. Such a resin composition includes a polymer having a halogen atom in a structural unit. As such a polymer, for example, a polymer having a structural unit represented by the following formula (I) or (II) is used.

（式（Ｉ）中、Ｒ₁は、水素原子、又は炭素数１〜４の炭化水素基若しくは置換可アルキル基を表し、Ｒ₂は、炭素数１〜４の炭化水素基又は置換可アルキル基を表し、Ｘはハロゲン原子を表す。）

(In the formula (I), R ₁ represents a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group, and R ₂ represents a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group. And X represents a halogen atom.)

式（II）中、Ｒ₃は、水素原子、又は炭素数１〜４の炭化水素基若しくは置換可アルキル基を表し、Ｒ₄は、少なくとも一つの水素がハロゲン置換された、炭素数１〜４の炭化水素基を表す。

In the formula (II), R ₃ represents a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group, and R ₄ has 1 to 4 carbon atoms in which at least one hydrogen is halogen-substituted. Represents a hydrocarbon group.

In the structural unit represented by the above formula (I), R ₁ and R ₂ are preferably each independently a hydrocarbon group having 1 to 4 carbon atoms, and both R ₁ and R ₂ are methyl groups. Particularly preferred. In the structural unit represented by the above formula (I), X is preferably fluorine, chlorine or the like, and particularly preferably chlorine. Specifically, the polymer preferably has a structural unit represented by the following formula (III).

  Moreover, as the structural unit contained in the polymer and represented by the above formula (II), for example, those represented by the following formulas (IV) to (VI) are preferable.

  As will be described later, in the imprint mold manufacturing method according to the first embodiment, a resin pattern 31 (FIG. 1) formed by patterning the resin layer 30 on the main surface 11 of the substrate 10 for imprint mold. (B)) is irradiated with ionizing radiation to improve the etching resistance of the resin pattern 31 (see FIG. 1C). When the resin composition has a structural unit represented by the above formula (I) or (II) (that is, the structural unit contains a halogen atom), the halogen atom is eliminated by irradiation with ionizing radiation, and the structural unit. By having an ester group (carbonyl group) therein, it is considered that radicals are generated by the irradiation of ionizing radiation to cause depolymerization of the polymer, and the free volume of the resin pattern 31 can be reduced. As a result, it is assumed that the etching resistance of the resin pattern 31 can be improved.

  The weight average molecular weight measured by the gel permeation chromatograph (GPC) of the said polymer should just be about 10,000-100,000. It is considered that when the weight average molecular weight of the polymer is within such a range, the effect of reducing the free volume of the resin pattern 31 by irradiation with ionizing radiation is excellent, and the etching resistance can be effectively improved.

  Content of the said polymer in the said resin composition is 80-100 mass%, for example, Preferably it is 95-100 mass%. When the content of the polymer in the resin composition is within the above range, the free volume of the resin pattern 31 can be effectively reduced and the etching resistance can be improved.

  In addition to the above polymer, the resin composition contains components generally contained in the imprint resin composition, such as an acid generator, a surfactant, a release agent, and an organic solvent, as necessary. May be.

  The method for forming the resin layer 30 on the hard mask layer 20 is not particularly limited. For example, the resin composition is applied on the hard mask layer 20 by a conventionally known coating method (spin coating method or the like). Thereafter, a method of forming by heating (pre-baking) and the like can be mentioned. The thickness of the resin layer 30 is preferably about 60 nm or less, and particularly preferably about 10 to 60 nm.

  Next, as shown in FIG. 1B, a resin pattern 31 is formed by patterning the resin layer 30 on the hard mask layer 20. Examples of the method for forming the resin pattern 31 include a photolithography method and an imprint lithography method.

  As a method of forming the resin pattern 31 by photolithography, for example, an electron beam drawing apparatus or the like is used to form a pattern latent image (electron beam irradiation site 32) by electron beam drawing on the resin layer 30, and predetermined development is performed. Examples thereof include a method of forming the resin pattern 31 through development processing using a liquid and rinsing processing using a predetermined rinsing liquid.

  As a method of forming the resin pattern 31 by imprint lithography, first, droplets of the imprint resin 40 are supplied onto the resin layer 30 as shown in FIG.

  In the step shown in FIG. 2A, the imprint resin 40 supplied onto the resin layer 30 exhibits etching resistance more than that of the resin layer 30 under the etching conditions in the later-described step (see FIG. 2D). The resin material is not particularly limited as long as it can be used, and a resin material that can be generally used in the imprint method can be used.

  Next, as shown in FIG. 2B, a predetermined imprint mold 50 is brought into contact with the imprint resin 40 supplied on the resin layer 30, and the imprint pattern 51 of the imprint mold 50 is imprinted. The imprint resin 40 is wetted and spread on the resin layer 30 while filling the print resin 40. Then, as shown in FIG. 2C, the imprint resin 40 filled in the fine concavo-convex pattern 51 is cured by ultraviolet irradiation or the like, and then the imprint mold 50 is peeled off, and the imprint resin 40 is configured. A resist pattern 41 is formed.

  The fine concavo-convex pattern 51 of the imprint mold 50 is a structure formed by inverting the fine concavo-convex pattern 2 of the imprint mold 1 (see FIG. 1E) manufactured in the imprint mold manufacturing method according to this embodiment. And has a size slightly larger than the fine uneven pattern 2.

  As will be described later, the resin pattern 30 is etched by using the resist pattern 41 formed on the resin layer 30 as a mask to form a resin pattern 31 (see FIG. 2D), and the resin pattern 31 is ionized. The etching resistance of the resin pattern 31 is improved by irradiating with radiation (see FIG. 1C). Due to the irradiation with the ionizing radiation, the free volume of the resin pattern 31 is reduced, and as a result, the dimension of the resin pattern 31 is slightly reduced (about 1 to 10 nm). Therefore, the dimension of the resin pattern 31 after irradiation with ionizing radiation is slightly smaller (about 2 to 20 nm) than the dimension of the resist pattern 41 formed using the imprint mold 50. Then, the fine concavo-convex pattern 2 of the imprint mold 1 is formed with a dimension corresponding to the dimension of the resin pattern 31 after irradiation with ionizing radiation. The dimension of the fine concavo-convex pattern 51 of the imprint mold 50 is as follows. The imprint mold 1 having the fine concavo-convex pattern 2 according to the design dimension can be produced by being slightly larger (about 2 to 20 nm) than the design dimension of the fine concavo-convex pattern 2 of the imprint mold 1 to be manufactured. .

  Although the dimension of the fine unevenness | corrugation pattern 2 of the imprint mold 1 manufactured in this embodiment is not specifically limited, It is preferable that it is a finer dimension, for example, the shape of the fine unevenness | corrugation pattern 2 is a line and space. In the case of a shape, the width in the short direction is preferably about 5 to 50 nm, and particularly preferably about 10 to 20 nm. Since the dimension of the fine uneven pattern 2 of the imprint mold 1 is as fine as the above range, the effect of this embodiment (the effect of improving the etching resistance of the resin pattern 31) is remarkably exhibited, and the dimensional uniformity is high. This makes it possible to manufacture an imprint mold having a low defect density.

  The resin pattern 31 after irradiation with ionizing radiation is formed with the same size as the fine concavo-convex pattern 2 of the imprint mold 1 manufactured in the present embodiment, but is high enough to withstand the etching process of the hard mask layer 20. It is necessary to have That is, the aspect ratio (height / width) of the resin pattern 31 tends to increase as the size of the fine uneven pattern 2 of the imprint mold 1 to be manufactured becomes finer. When the aspect ratio of the resin pattern 31 is increased, there is a high possibility that the resin pattern 31 may fall down or the dimensions of the fine uneven pattern 2 of the imprint mold 1 may be uneven. However, in this embodiment, the resin pattern 31 can be irradiated with ionizing radiation to improve etching resistance. Therefore, even if the size of the fine concavo-convex pattern 2 of the imprint mold 1 to be manufactured is reduced, Accordingly, it is not necessary to increase the resin pattern 31 and the aspect ratio of the resin pattern 31 can be set small. Therefore, the imprint mold manufacturing method according to the present embodiment is useful for manufacturing the imprint mold 1 having the fine concavo-convex pattern 2 having the fine dimensions as described above, and in particular, further miniaturization of the dimensions is required. It can be said that it is useful for the manufacture of an imprint mold (imprint mold for semiconductor devices) used for producing a semiconductor device.

  The imprint mold 50 used for forming the resist pattern 41 may be one in which a fine uneven pattern 51 is formed on one surface (main surface) 53 of a flat substrate 52. It is good (see FIG. 3A), and has a convex structure portion 54 on one surface 53 side of the flat substrate 52, and the fine uneven pattern 51 is formed on the main surface 55 of the convex structure portion 54. May be used (see FIG. 3B)

  Subsequently, as shown in FIG. 2D, the resin layer 30 is dry-etched using the resist pattern 41 from which the remaining film has been removed as an etching mask as necessary to form a resin pattern 31.

  Thereafter, as shown in FIG. 1C, the resin pattern 31 is irradiated with ionizing radiation 60. The resin composition constituting the resin pattern 31 in the present embodiment includes a polymer having a structural unit represented by the above formula (I) or (II), and the polymer is irradiated with ionizing radiation 60. As the halogen atoms are eliminated, depolymerization occurs and the free volume of the resin pattern 31 is reduced. Since the free volume is reduced, the etching gas can be prevented from entering the resin pattern 31, and as a result, the etching resistance of the resin pattern 31 can be improved.

  Examples of the ionizing radiation 60 applied to the resin pattern 31 in the step shown in FIG. 1C include an electron beam, hard X-ray, soft X-ray, and γ-ray.

  The conditions for irradiating the resin pattern 31 with the ionizing radiation 60 are not particularly limited. For example, when the resin pattern 31 is irradiated with an electron beam as the ionizing radiation 60, the acceleration voltage in the electron beam irradiation can be in the range of 30 to 300 kV, and the irradiation dose can be in the range of 2 to 4000 Mrad. Moreover, in FIG.1 (c), although the ionizing radiation 60 is irradiated from the upper direction of the resin pattern 31, it is not limited to such an aspect, The ionizing radiation 60 is from the imprint mold base material 10 side. May be irradiated. Furthermore, the irradiation treatment with the ionizing radiation 60 can be performed in an air atmosphere, a nitrogen atmosphere, or a vacuum atmosphere.

  Subsequently, as shown in FIG. 1D, the hard mask layer 20 is dry-etched using the resin pattern 31 that is irradiated with ionizing radiation 60 and has improved etching resistance as an etching mask. 21 is formed.

  Finally, as shown in FIG. 1E, the imprint mold substrate 10 is subjected to a dry etching process using the hard mask pattern 21 as an etching mask to form fine irregularities on the main surface 11 of the imprint mold substrate 10. Pattern 2 is formed and hard mask pattern 21 is removed. Thereby, the imprint mold 1 which has the fine uneven | corrugated pattern 2 can be manufactured.

  As described above, according to the imprint mold manufacturing method of the present embodiment, the resin pattern 31 is irradiated with the ionizing radiation 60 on the resin pattern 31 used as a mask for forming the hard mask pattern 21. Etching resistance can be improved. Therefore, the aspect ratio of the resin pattern 31 can be reduced, and the hard mask pattern 21 with high dimensional uniformity and low defect density can be formed. As a result, the imprint mold 1 with high dimensional uniformity and low defect density can be manufactured.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example etc. are given and this invention is demonstrated further in detail, this invention is not limited to the following Example etc. at all.

[Example 1]
A quartz substrate is prepared as an imprint mold base material 10 in which a hard mask layer 20 made of Cr having a thickness of 3 nm is provided on the main surface 11 and contains a polymer having a structural unit represented by the following formula (III). A positive resist (product name: ZEP520A, manufactured by Nippon Zeon Co., Ltd.) was diluted to 16% by mass with methoxybenzene, applied on the hard mask layer 20 by spin coating, and subjected to a heat treatment at 180 ° C. for 3 minutes. A resin layer 30 having a thickness of 30 nm was formed (see FIG. 1A).

  Next, an imprint resin 40 having the following composition is supplied onto the resin layer 30 by an ink jet method, and an imprint mold 50 having a line-and-space-like fine uneven pattern 51 (dimension in the short direction of the fine uneven pattern 51: 20 nm). ) Was used to form a resist pattern 41 (see FIGS. 2A to 2C).

<Imprint resin composition>
・ 38% by mass of isobornyl acrylate
・ 20% by mass of ethylene glycol diacrylate
・ Butyl acrylate 38% by mass
2-hydroxy-2-methyl-1-phenyl-propan-1-one 2% by mass
・ 2-perfluorodecylethyl acrylate 1% by mass
・ Methyl perfluorooctanolate 1% by mass

  After the residual film of the resist pattern 41 is removed by ashing, the resin layer 30 is dry-etched using an etching gas (oxygen) using the resist pattern 41 as a mask, and a resin pattern 31 (short dimension: 18 nm, height) : 30 nm, aspect ratio: 1.67) (see FIG. 2D).

  Then, the electron beam was irradiated to the one part area | region of the resin pattern 31 in air | atmosphere atmosphere using the electron beam irradiation apparatus (refer FIG.1 (c)). The electron beam irradiation conditions were an acceleration voltage of 175 kV and an irradiation dose of 500 Mrad to 2400 Mrad.

Then, the hard mask layer 20 was dry-etched (etching gas: Cl ₂ + O ₂ ) using the resin pattern 31 in which a part of the region was irradiated with the electron beam as a mask to form the hard mask pattern 21 (FIG. 1). (See (d)).

  When the main surface 11 of the substrate 10 for imprint mold in which the hard mask pattern 21 was formed in this way was confirmed with an electron microscope, a hard mask pattern was not formed on the region of the resin pattern 31 that was irradiated with the electron beam. 21 was formed. Further, the resin pattern 31 remained on the hard mask pattern 21. On the other hand, the resin pattern 31 did not remain in the region of the resin pattern 31 where the electron beam was not irradiated, and the desired hard mask pattern 21 was not formed.

[Comparative Example 1]
A resin pattern 31 was formed in the same manner as in Example 1 except that a positive resist material containing a polymer having no halogen atom as a structural unit (product name: mr-I 7000E, manufactured by Microresist) was used. After irradiating a partial region of the resin pattern 31 with an electron beam, a dry etching process was performed using the resin pattern 31 as a mask to form a hard mask pattern 21.

  When the main surface 11 of the substrate 10 for imprint mold in which the hard mask pattern 21 was formed in this way was confirmed with an electron microscope, the resin pattern 31 irrespective of whether or not the resin pattern 31 was irradiated with an electron beam. Did not remain, and the desired hard mask pattern 21 was not formed.

[Comparative Example 2]
A resin pattern 31 is formed in the same manner as in Comparative Example 1 except that the resin layer 30 has a thickness of 60 nm and the resin pattern 31 is not irradiated with an electron beam, and dry etching is performed using the resin pattern 31 as a mask. A hard mask pattern 21 was formed.

  The main surface 11 of the substrate 10 for imprint mold in which the hard mask pattern 21 was formed in this way was confirmed with an electron microscope. As a result, although the hard mask pattern 21 was formed, defects due to the collapse of the resin pattern 31 were observed. It was confirmed that this occurred.

[Example 2]
The resin layer 30 formed in the same manner as in Example 1 was irradiated with an electron beam using an electron beam drawing apparatus to form a pattern latent image. The resin layer 30 is developed using a developer (product name: ZED-N50, manufactured by Nippon Zeon Co., Ltd.), rinse solution (product name: ZMD-B, manufactured by Nippon Zeon Co., Ltd.), and isopropyl alcohol ( A rinsing process using IPA) was performed to form a resin pattern 31 (dimension in the short direction: 18 nm, height: 30 nm, aspect ratio: 1.67) (see FIG. 1B).

  Then, the electron beam was irradiated to the one part area | region of the resin pattern 31 in air | atmosphere atmosphere using the electron beam irradiation apparatus (refer FIG.1 (c)). The electron beam irradiation conditions were an acceleration voltage of 175 kV and an irradiation dose of 500 Mrad to 2400 Mrad.

Then, the hard mask layer 20 was dry-etched (etching gas: Cl ₂ + O ₂ ) using the resin pattern 31 in which a part of the region was irradiated with the electron beam as a mask to form the hard mask pattern 21 (FIG. 1). (See (d)).

  When the main surface 11 of the substrate 10 for imprint mold in which the hard mask pattern 21 was formed in this way was confirmed with an electron microscope, a hard mask pattern was not formed on the region of the resin pattern 31 that was irradiated with the electron beam. 21 was formed. Further, the resin pattern 31 remained on the hard mask pattern 21. On the other hand, the resin pattern 31 did not remain in the region of the resin pattern 31 where the electron beam was not irradiated, and the desired hard mask pattern 21 was not formed.

[Experimental Example 1]
The resin layer 30 formed in the same manner as in Example 1 is irradiated with an electron beam (acceleration voltage: 175 kV, irradiation dose: 2400 Mrad) and included in each of the electron beam irradiation site and the electron beam non-irradiation site of the resin layer 30. The IR spectrum of the polymer was measured. The measurement results are shown in FIG. 4A is an IR spectrum of a polymer contained in an electron beam irradiation site, and FIG. 4B is an IR spectrum of a polymer contained in an electron beam non-irradiation site.

As shown in FIG. 4, in the IR spectrum of the polymer contained in the electron beam irradiation site, a change in peak was observed (1700-1800 cm ^−1), which can be judged as the elimination of the halogen atom of the structural unit. Near, see the circled portion in FIGS. 4 (a) and 4 (b)). From this, by irradiating a resin pattern comprising a resin composition containing a polymer having the structural unit represented by the above formula (III) with ionizing radiation such as an electron beam, halogen atoms are removed from the irradiated site. It is believed that the free volume can be reduced.

  As is clear from the above-described Examples 1 and 2 and Comparative Examples 1 and 2, the resin pattern 31 used as a mask for forming the hard mask pattern 21 is irradiated with ionizing radiation such as an electron beam after irradiation. The etching resistance of the resin pattern 31 can be improved. As a result, even if the aspect ratio of the resin pattern 31 is small, the desired hard mask pattern 21 can be formed with high accuracy, and an imprint mold with high dimensional uniformity and low defect density can be manufactured. .

  The present invention is useful as a method for manufacturing an imprint mold used in a nanoimprint process for forming a fine uneven pattern on a semiconductor substrate or the like in the process of manufacturing a semiconductor device.

DESCRIPTION OF SYMBOLS 1 ... Imprint mold 2 ... Fine uneven | corrugated pattern 10 ... Base material for imprint molds (base material to be processed)
DESCRIPTION OF SYMBOLS 11 ... Main surface 30 ... Resin layer 31 ... Resin pattern 40 ... Imprint resin (imprint material)
41. Resist pattern (pattern)
50 ... Imprint mold 51 ... Fine uneven pattern

Claims (8)

A pattern forming step of forming a resin pattern on the main surface of the substrate to be processed;
An ionizing radiation irradiation step of irradiating the resin pattern with ionizing radiation;
A substrate etching step of etching the substrate to be processed using the resin pattern irradiated with the ionizing radiation as a mask,
The resin composition which comprises the said resin pattern contains the polymer which has a halogen atom in a structural unit, The manufacturing method of the imprint mold characterized by the above-mentioned. The said resin composition contains the polymer which has a structural unit shown to following formula (I), The manufacturing method of the imprint mold of Claim 1 characterized by the above-mentioned.

(In the formula (I), R ₁ represents a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group, and R ₂ represents a hydrocarbon group having 1 to 4 carbon atoms or a substituted alkyl group. And X represents a halogen atom.) In the formula (I), the production method of the imprint mold according to claim 2, wherein R ₁ is a hydrocarbon group having 1 to 4 carbon atoms. In the said formula (I), R < ₁ > is a methyl group, The manufacturing method of the imprint mold of Claim 2 or 3 characterized by the above-mentioned. In the formula (I), the production method of the imprint mold according to claim 2, wherein R ₂ is a hydrocarbon group having 1 to 4 carbon atoms. In the formula (I), the production method of the imprint mold according to any one of claims 2-5, wherein R ₂ is a methyl group. The pattern forming step includes
Forming a pattern latent image by irradiating an active energy ray to a resin layer formed of the resin composition formed on the main surface of the workpiece; and
The method for producing an imprint mold according to claim 1, further comprising: developing the resin layer on which the pattern latent image is formed. The pattern forming step includes
The imprint material is supplied onto the resin layer formed of the resin composition, which is formed on the main surface of the workpiece, and the imprint mold having an uneven pattern corresponding to the resin pattern is used. An imprint process for forming a mask pattern composed of an imprint material;
A method for producing an imprint mold according to claim 1, further comprising: a resin layer etching step of etching the resin layer using a mask pattern made of the imprint material as a mask. .

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