JP2014079903A - Production method of mold for imprinting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide techniques in the production of a mold for imprinting, by which dimensional fluctuations in a pattern can be decreased and a pattern can be minimized while productivity of the mold for imprinting is increased.SOLUTION: A production method of a mold for imprinting includes: a first step of forming a hard mask layer 2 and a resist layer on a substrate 1, and then forming a resist pattern 3a by exposure and development; a second step of forming a mask pattern 4a in a pitch narrower than that of the resist pattern 3a on the hard mask layer 2 by a self-matching double patterning process using the resist pattern 3a as a core pattern; and a third step of etching the hard mask layer 2 by using the mask pattern 4a to form a hard mask pattern and then etching the substrate 1 by using the hard mask pattern to form a concavo-convex pattern.

Description

  The present invention relates to a method for manufacturing an imprint mold.

  An imprint technique and an imprint lithography technique (hereinafter also simply referred to as an imprint technique) are known as pattern transfer duplication techniques. In this imprint technique, an original pattern (hereinafter referred to as “imprint mold”) in which a concavo-convex pattern is formed on a main surface of a substrate or a sheet or a film is transferred to a transfer target body through a resist layer made of UV curable resin or the like. Alternatively, it is a technique for directly transferring the uneven pattern. When manufacturing an imprint mold to be used in the imprint technology, for example, a mold manufacturing blank is used in which a hard mask layer is formed on the main surface of a substrate made of synthetic quartz as a base material (for example, Patent Documents). 1).

Hereinafter, a specific manufacturing procedure of the imprint mold will be described by taking an optical imprint mold using synthetic quartz as a substrate as an example.
First, a hard mask layer is formed on the main surface of a substrate made of synthetic quartz that has been appropriately precisely polished, and a resist is applied on the hard mask layer to form a resist layer. Next, the resist layer is exposed (pattern drawing) and developed to form a resist pattern. Next, the hard mask pattern is formed by etching the hard mask layer using the resist pattern as a mask. Next, the substrate is etched using the hard mask pattern as a mask. Finally, the imprint mold is completed in which the hard mask pattern is removed to form an uneven pattern on the main surface of the substrate.

  By the way, in the imprint mold, the pattern miniaturization is continuously demanded. In particular, for applications that require an extremely fine uneven pattern with a pattern pitch of 30 nm or less, the resist layer exposure process is currently performed by the electron beam direct writing method. In the electron beam direct writing method, a resist having sensitivity to an electron beam is formed in the resist layer when forming a dimensional region of an extremely fine pattern that cannot be formed by a reduction projection exposure method (photolithography technology) using an exposure mask. A resist pattern is exposed (pattern drawing) by coating and forming, and directly irradiating the resist layer with an electron beam, and then developing processing to generate a desired pattern.

  When an imprint mold is manufactured by a lithography method (electron beam lithography method) employing an electron beam direct drawing method, the desired pattern dimensions can be obtained from the resist material and the type of developer used in the subsequent development process. Whether or not a desired very fine pattern can be formed (that is, resolution limit) is determined. For example, in the case of using a non-chemical amplification type resist material made of a polymer compound (hereinafter referred to as “polymer resist”), the lower the developer (organic solvent), the higher the resolution. can get. On the other hand, the more the fine pattern is formed, that is, the higher the resolution is obtained by using a poor solvent, the more the exposure required for electron beam drawing increases. Productivity decreases. In the electron beam lithography method, at present, the pitch of a line & space pattern (also referred to as an LS pattern) is 36 nm (nanometer), the half pitch is 18 nm, and the hole pattern dimension (diameter) is 12.5 nm (nanometer). ) Can be formed up to a minute pattern.

JP 2011-73305 A JP 2011-215243 A

As described above, in a polymer resist that is a non-chemical amplification type, the higher the developing solution composed of an organic solvent, the higher the resolution. However, on the other hand, the electron that exposes the resist layer in electron beam exposure (pattern drawing) as necessary and sufficiently so as to form a very fine pattern, that is, to obtain high resolution using a poor solvent. The radiation dose (hereinafter referred to as “required exposure”) increases, and as a result, the productivity in the pattern drawing process decreases.
Further, the variation in pattern dimensions deteriorates when the pattern formed on the substrate approaches the resolution limit. For example, when describing LWR (Line Width Roughness), which is one index of variation in pattern dimensions, in an LS pattern with a half pitch of about 48 nm, the LWR is about 3 nm with a 3σ value, and the half pitch is about 20 nm. When the LS pattern is changed, the LWR deteriorates to about 5 nm. The same applies to LER (Line Edge Roughness), which is another index of pattern dimensional variation. An outline of the relationship between LWR and pattern pitch is shown in FIG. Further, as described above, the electron beam direct writing method that is superior to the reduction projection exposure method using the exposure mask still has a resolution limit.

  The main object of the present invention is to improve the productivity in the pattern drawing process by the electron beam direct drawing method when manufacturing an imprint mold, and to reduce the size variation of the pattern while reducing the pattern size variation. It is to provide a technology capable of achieving the above. In addition, the technology for manufacturing imprint molds on the surface with finer concavo-convex patterns (less than the resolution limit in the electron beam drawing method, or less) than the pattern dimensions that cannot be realized by the electron beam direct drawing method alone. It is to provide.

The first aspect of the present invention is:
A substrate constituting the imprint mold, at least a hard mask layer on the main surface thereof, and a resist layer formed thereon, and a predetermined treatment on the resist layer, thereby forming a resist pattern at a desired predetermined pitch. A first step of forming;
A second step of forming a mask pattern at a pitch narrower than the pitch of the resist pattern on the hard mask layer by a self-aligning double patterning method using the resist pattern as a core pattern;
A hard mask pattern is formed by etching the hard mask layer using the mask pattern, and an uneven pattern is formed on the main surface of the substrate by etching the substrate using the hard mask pattern. 3 steps,
It is a manufacturing method of the mold for imprint characterized by comprising.

The second aspect of the present invention is:
The predetermined process in the first step of the first aspect is an electron beam direct writing method in which a resist layer is exposed with an electron beam to draw a pattern, and then a development process is performed to form a resist pattern. It is a manufacturing method of the mold for imprints as described in the 1st mode characterized by the above-mentioned.

The third aspect of the present invention is:
The first process according to the first aspect is characterized in that the predetermined process of the first step of the first aspect is an imprint method performed by pressing an imprint mold having an uneven pattern on the main surface of the substrate against the resist layer. It is a manufacturing method of the mold for imprint as described in aspect.

The fourth aspect of the present invention is:
The imprint for imprint according to the first, second or third aspect, further comprising a step of narrowing the width of the resist pattern between the first step and the second step of the first aspect. It is a manufacturing method of a mold.

According to a fifth aspect of the present invention,
The first step includes
Forming a hard mask layer and a resist layer in order on the main surface of the substrate;
Forming a resist pattern by applying a predetermined treatment to the resist layer,
The second step includes
Forming a mask layer in a state of covering an upper surface and side surfaces of the resist pattern and an exposed surface of the hard mask layer not covered with the resist pattern;
Etching the mask layer so that the upper surface of the resist pattern is exposed, thereby leaving a part of the mask layer as the mask pattern on both side surfaces of the resist pattern. It is the manufacturing method of the mold for imprint as described in a 1st, 2nd or 3rd aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the productivity in the pattern drawing process by an electron beam direct drawing method can be improved in the mold for imprint. Further, the pattern can be miniaturized while reducing the dimensional variation of the pattern. Furthermore, an imprint mold having a very fine pattern on the main surface that cannot be formed by the electron beam direct writing method alone can be produced.

It is the schematic of the relationship between LWR and pattern pitch. It is a process flow figure explaining the manufacturing method of the imprint mold concerning a 1st embodiment of the present invention (the 1). It is a process flow figure explaining the manufacturing method of the imprint mold concerning a 1st embodiment of the present invention (the 2). It is a process flow figure (the 3) explaining the manufacturing method of the mold for imprints concerning a 1st embodiment of the present invention. It is a figure which shows the relationship between a pattern dimension and required exposure amount. It is a process flowchart (the 1) explaining the manufacturing method of the mold for imprint which concerns on the 2nd Embodiment of this invention. It is a process flowchart (the 2) explaining the manufacturing method of the imprint mold which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
2 to 4 are process flow diagrams for explaining a method for manufacturing an imprint mold according to the first embodiment of the present invention. Hereinafter, each step will be described.

  First, as shown in FIG. 2 (A), a substrate 1 to be a base (base material) of an imprint mold to be manufactured is prepared, and a hard mask layer 2 is provided on one main surface of the substrate 1. Form. As the substrate 1, for example, a light-transmitting substrate made of synthetic quartz or the like, more specifically, a substrate that transmits light having a wavelength for curing an imprint resist (photo-curing resin) in the photo-imprinting method is used. Can do. Next, the hard mask layer 2 is formed on the main surface of the substrate 1 by, for example, sputtering. As the hard mask layer 2, for example, when the substrate 1 is a quartz substrate, a single-layer metal film (such as chromium nitride) containing chromium is formed.

  Next, as shown in FIG. 2B, a resist layer 3 is formed on the hard mask layer 2. The resist layer 3 is formed, for example, by applying a positive resist on the hard mask layer 2 by spin coating or the like, and then baking if necessary. As a resist material used for forming the resist layer 3, a resist having sensitivity to an electron beam (for example, ZEP520A manufactured by Nippon Zeon Co., Ltd.) can be used. Here, the resist material used for forming the resist layer 3 is not limited to a positive type, and may be a negative type.

  Next, as shown in FIG. 2C, a desired design pattern is drawn on a part of the resist layer 3 by irradiation (exposure) with an electron beam e. In this step, the substrate of FIG. 2B is set on a sample stage of an electronic drawing apparatus (not shown), the resist layer 3 is exposed by an electron beam direct drawing method, and a pattern is drawn. In that case, if the resist layer 3 is a positive type resist, a part (exposed portion) of the resist layer 3 irradiated with the electron beam e is solubilized in the developer.

  Next, as shown in FIG. 2D, a resist pattern 3a is formed by developing the substrate of FIG. 2C after the exposure (pattern drawing) of the resist layer 3 in the previous step. The resist pattern 3a is obtained by dissolving and removing a part (solubilized portion) of the resist layer 3 with a developer when the resist layer 3 that has been exposed (pattern drawing) is developed.

Next, as shown in FIG. 3A, a mask layer is formed on the main surface of the substrate of FIG. 2D so as to cover the upper and side surfaces of the resist pattern 3a and the exposed portion of the hard mask layer 2. 4 is formed. For example, a silicon oxide film (SiO ₂ ) is formed as the mask layer 4. The mask layer 4 is desirably formed by an ALD (Atomic Layer Deposition) method in order to cover the upper surface and side surfaces of the resist pattern 3a with a uniform film thickness.

  Next, as shown in FIG. 3B, the mask layer 4 is etched by a predetermined amount. Specifically, the mask layer 4 is etched (etched back) so that the upper surface of the resist pattern 3a and the mask layer 4 covering the exposed portion of the hard mask layer 2 are exposed. Thereby, a part of the mask layer 4 remains as a mask pattern 4a on both side surfaces of the resist pattern 3a. The mask pattern 4a is formed adjacent to the side surface of the resist pattern 3a. Further, two mask patterns 4a are formed on the left and right sides for each resist pattern 3a. For this reason, two mask patterns 4a are formed between two adjacent resist patterns 3a with a gap therebetween. Etching of the mask layer 4 is performed, for example, by dry etching using a fluorine-based gas.

  Next, the resist pattern 3a is completely removed by etching. Etching (removal) of the resist pattern 3a is performed by, for example, plasma etching using oxygen and argon. As a result, as shown in FIG. 3C, a plurality of (double) mask patterns 4 a remain on the hard mask layer 2 of the substrate 1.

  Next, the hard mask layer 2 is etched using the mask pattern 4a as an etching mask. As a result, as shown in FIG. 4A, a hard mask pattern 2a is formed on the main surface of the substrate 1 following the shape of the mask pattern 4a. For example, when the hard mask layer 2 is a chromium nitride film, the hard mask layer 2 is etched by dry etching using a chlorine-based gas and an oxygen gas.

Next, as shown in FIG. 4B, the substrate 1 is etched using the hard mask pattern 2a as an etching mask. Thereby, an uneven pattern (hereinafter also referred to as a mold pattern) 1a is formed on the main surface of the substrate 1 following the shape of the hard mask pattern 2a. Etching of the substrate 1 is performed by dry etching using a fluorine-based gas, for example, when the substrate 1 is synthetic quartz.
At this time, when the substrate 1 is a quartz substrate and the mask pattern 4a is a silicon oxide film (SiO ₂ ), the mask pattern 4a is also etched away by the etching process of the substrate 1.
After the substrate 1 is etched, as shown in FIG. 4C, by removing the hard mask pattern 2a, or when the residue of the mask pattern 4a remains on the hard mask pattern 2a, the residue is removed. In addition, by removing the hard mask pattern 2a, only the mold pattern 1a is left on the substrate 1. The removal of the hard mask pattern 2a is performed by, for example, a wet etching process using a chromium etching solution.

  Through the above steps, the substrate 1 integrally having the uneven mold pattern 1a, that is, the imprint mold is obtained.

<Effect of the first embodiment>
In the semiconductor manufacturing field, a double patterning technique has already been put into practical use as one of techniques for miniaturizing a pattern.
In the first embodiment of the present invention, the uneven mold pattern 1a is formed on the substrate 1 using a self-aligned double patterning (SADP) method. Specifically, the resist pattern 3a formed by the electron beam direct writing method is used as a core pattern (core) to form a finer mask pattern 4a, and the hard mask pattern 2a is formed using the mask pattern 4a. Forming. As a result, the hard mask pattern 2a can be formed at half the pitch of the resist pattern 3a. Then, the concave / convex mold pattern 1a can be formed on the substrate 1 at the same pitch as the hard mask pattern 2a, and an imprint mold having a concave / convex pattern having a desired predetermined pattern pitch is obtained.

  Here, in the present invention, in forming a fine pattern (18 nm half pitch) at a level that can be realized even by an electron beam direct writing method, the process becomes complicated when considered simply. A patterning technique is employed with the result that high technical effects can be realized. This will be described in detail below.

(Improvement of LWR)
For example, when the concave / convex mold pattern 1a is formed on the main surface of the substrate 1 at a 36 nm pitch (18 nm half pitch) close to the resolution limit of the electron beam resist ZEP520A, the resist pattern 3a is used as a design value from the beginning. When the electron beam direct writing method is used alone and directly, the dimensional variation (LWR) of the pattern becomes as large as about 5 nm (3σ value). On the other hand, according to the present embodiment, first, a resist pattern is formed on the substrate 1 by a direct electron beam drawing method at a pitch of 72 nm (36 nm half pitch) corresponding to twice the desired pattern pitch. 3a is formed. Therefore, good pattern quality can be obtained when the pattern dimension variation (LWR) is about 3 nm (3σ value). Then, using this resist pattern 3a as a core pattern, a mask pattern 4a having a pitch of 36 nm (half pitch of 18 nm) is formed by the SADP method. Then, an uneven mold pattern 1a is formed on the main surface of the substrate 1, and the imprint mold is completed. By this SADP method, the dimensional variation (LWR) of the pattern is further improved from about 3 nm.
That is, compared to the case where the resist pattern 3a is directly formed at a pitch of 36 nm by the electron beam direct writing method alone and an imprint mold is manufactured, the mold manufacturing method according to the present invention increases the dimensional variation of the pattern with certainty. Can be reduced.

(Higher sensitivity, shorter exposure time)
When a fine resist pattern is directly formed by a direct electron beam lithography method using a polymer type resist, it is necessary to develop with a developer with a poorer solvent. In that case, higher resolution is obtained as the solvent of the developer is a poor solvent. However, the necessary exposure amount increases exponentially as the pattern becomes finer (see FIG. 5).
For example, when the ZEP520A is used as a resist material and the 18 nm LS pattern (18 nm half pitch, 36 nm pitch) is formed, the required exposure amount increases to about 675 μC / cm ² (the drawing acceleration voltage is 100 kV, and the developer is, for example, fluorocarbon. And a mixture of isopropyl alcohol). On the other hand, when forming a 36 nm LS pattern (36 nm half pitch, 72 nm pitch), the developer may be a relatively better solvent than the mixture of fluorocarbon and isopropyl alcohol, for example, acetic acid-n-amyl. The necessary exposure amount at that time decreases to about 115 μC / cm ² (the drawing acceleration voltage is 100 kV). This means that, in the case of forming a 36 nm LS pattern, the exposure (pattern drawing) time of the resist layer can be reduced to 1/6 as compared with the case of forming an 18 nm LS pattern.
Further, in the hole pattern, the required exposure amount is about 160 μC / cm ² to form a hole array pattern with a 50 nm pitch, whereas the required exposure amount is about to form a hole array pattern with a 25 nm pitch. , Approximately 10 times that of 1600 μC / cm ² (exposure accelerating voltage is 100 kV, different developers). This means that if a hole pattern with a 50 nm pitch is to be formed, the exposure (pattern drawing) time of the resist layer can be reduced to 1/10 as compared with the case of forming a hole pattern with a 25 nm pitch. Means.
That is, compared to the case where the resist pattern 3a is directly formed at a desired predetermined pattern pitch by the electron beam direct writing method alone and the mold for imprinting is manufactured, the mold manufacturing method of the present invention produces more in the drawing process. The property can be improved from 6 times to 10 times.
Here, for example, a hole array pattern with a pitch of 25 nm (a pattern for bit patterned media) is directly applied to a resist layer in a region of a radius of 15 mm to a radius of 30 mm of a magnetic medium for 2.5 inch hard disk drive with a point beam type electron beam directly. When exposure and pattern drawing are performed by a drawing apparatus, a very long time (number of days) of about 14 to 21 days is required from the start to the end of pattern drawing. Therefore, according to the mold manufacturing method of the present invention, the time required for this pattern drawing process can be greatly shortened from 1.4 days to 2.1 days, which is about 1/10.

  The inventor of the present application has focused on this point, and has come up with the present invention, thinking that the disadvantage associated with the adoption of the double patterning technology can be reduced or eliminated by a trade-off with the profit obtained thereby. That is, in the present invention, by adopting the double patterning technique, the pitch of the resist pattern 3a formed by the electron beam direct writing method is expanded to twice the pitch of the final desired mold pattern 1a. By reducing the required exposure, the total work time required for manufacturing the imprint mold was reduced. Further, in that case, among the double patterning techniques, the working time is reduced by adopting the SADP method in particular.

Specifically, for example, when a pattern having a desired pattern pitch is exposed to a desired area without enlarging the pattern pitch, it is assumed that the exposure time required for the exposure is 480 hours (20 days). If the exposure time of 1/8 (6 to 10 times in the above example, the reciprocal of the average value) is sufficient due to the expansion of the pitch, the time is shortened by 420 hours (17.5 days). For this reason, if the increase in the work time accompanying the process addition in FIGS. 3A to 3C is within 420 hours, the increase in the process addition can be completely canceled by the time reduction. it can. As a result, the working time can be greatly shortened and the dimensional variation of the pattern can be greatly reduced without increasing the working time. That is, it is possible to satisfy both the request for reducing the working time and the request for reducing the dimensional variation of the pattern at the same time.
Further, since the pattern drawing (exposure) time is shortened, the following advantages can be obtained. That is, when the pattern drawing (exposure) time (period) becomes long, when an environmental change that adversely affects resist drawing occurs from the start to the end of pattern drawing, that is, when an earthquake or the like occurs, for example, As a result, a positional deviation of pattern drawing occurs. In addition, when the power supply voltage fluctuates due to lightning or the like, the pattern drawing position deviation, the exposure amount fluctuation, and the like occur due to the influence. In addition, all pattern drawing processes performed so far may be wasted. Also, the exposure apparatus may need to be adjusted depending on the magnitude of the earthquake. Furthermore, when the pattern drawing (exposure) time (period) becomes long, instability in operation of the electron beam drawing apparatus (for example, fluctuation of exposure amount, positional deviation of pattern drawing, etc.) tends to appear in the pattern drawing result. In addition, there is a high probability that an unexpected instability of the operation of the electron beam drawing apparatus (for example, variation in exposure amount, positional deviation of pattern drawing, etc.) will occur. In this respect, if the drawing time is shortened, there is an advantage that such a risk can be reduced.
Furthermore, the adoption of the SADP method requires only one exposure / development, so that the number of working steps and the working time can be reduced compared with the case of employing other double patterning technology that requires two times. Can do.
As described above, the present invention can realize a high technical effect as a result by adopting the double patterning technique which is likely to suffer from the cost disadvantage due to the complicated process.

(Improvement of resolution limit)
When a fine resist pattern is directly formed by the electron beam direct writing method alone, the performance limit of the electron beam drawing apparatus, the limit of the resist performance, the type or configuration of the mold manufacturing substrate, etc. are determined by these. There is a resolution limit. For example, the resolution limit when the ZEP520A is used as a resist material is an 18 nm LS pattern (18 nm half pitch, 36 nm pitch). Therefore, the imprint of the present invention is not only in terms of improvement in pattern drawing productivity and pattern size variation but also in the case of focusing only on the resolution limit, that is, how fine a pattern can be formed. According to the mold manufacturing method, a pattern pitch that is half the dimension (pattern pitch) of an extremely fine pattern that can be formed by an electron beam direct writing method can be simply realized. Specifically, a 9 nm LS pattern can be formed by the SADP method using an 18 nm LS pattern (18 nm half pitch, 36 nm pitch) close to the resolution limit of the resist pattern that can be formed by the electron beam direct writing method as a core pattern. become able to.

<Second Embodiment>
6 and 7 are process flow diagrams illustrating a method for manufacturing an imprint mold according to the second embodiment of the present invention.

  First, as shown in FIG. 6 (A), the pattern size is larger than the final product, which is an imprint mold (hereinafter simply referred to as a mold) having an uneven pattern having a desired pattern pitch. In addition, an intermediate mold 5 having a concavo-convex pattern 5a having a double pattern pitch is prepared. The intermediate mold 5 may form a resist pattern by an electron beam direct drawing method. On the other hand, as shown in FIG. 6B, a substrate 1 is prepared as a base for an imprint mold as a final product, and a hard mask layer 2 and a resist are formed on one main surface of the substrate 1. Layer 3 is formed in sequence.

  Next, the pattern is transferred to the substrate 1 that is a transfer target by using the intermediate mold 5 by the imprint method. Specifically, as shown in FIG. 6C, the concave / convex pattern 5a of the intermediate mold 5 and the resist layer 3 of the substrate 1 are made to face each other, and then, as shown in FIG. Press against 1 and hold. Further, in a state where the intermediate mold 5 is pressed against the substrate 1, the resist layer 3 is cured by irradiating light onto the imprinting resist layer 3 made of, for example, a photocurable resin.

  Next, as shown in FIG. 7A, by removing the intermediate mold 5 from the substrate 1, the unevenness pattern 5 a of the intermediate mold 5 is reversed to the imprint resist layer 3 on the substrate 1. The transfer is formed. Thereafter, as shown in FIG. 7B, a thin film (residual film) of the imprint resist layer 3 covering the surface of the hard mask layer 2 (the portion corresponding to the convex portion of the concavo-convex pattern of the mold 5) is formed. It is removed by ozone plasma etching or the like. Thereby, a resist pattern 3 a is formed on the hard mask layer 2 of the substrate 1. Subsequent steps are performed in the same manner as in the first embodiment.

<Effects of Second Embodiment>
In the second embodiment of the present invention, a resist pattern is formed by an electron beam direct writing method to produce an imprint mold (intermediate mold 5). And the said intermediate mold 5 comprises the uneven | corrugated pattern formed with the pattern pitch of 2 times the final desired pattern pitch. Then, using the intermediate mold 5, a resist pattern 3a is formed on the hard mask layer 2 of the mold production substrate 1 which is a transfer target, by imprinting.
Here, first, since the intermediate mold 5 is formed with a pattern pitch twice as large as the final desired pattern pitch, the uneven pattern (5a) is compared with the case where the pattern is formed with the final desired pattern pitch. The dimensional variation (i.e., LWR or LER) is small and good.
Next, when the resist pattern 3a is formed by the imprint method, the dimensional variation of the concave / convex pattern (5a) of the intermediate mold 5 is compared with the resist pattern 3a obtained in the first embodiment. In general, the dimensional variation of the obtained resist pattern 3a becomes better. This is considered to be due to a buffering effect (smoothing effect) due to the thickness of the release agent formed on the surface of the uneven pattern of the intermediate mold 5 during imprinting.
The dimensional variation of the resist pattern 3a formed in the second embodiment follows the hard mask pattern 2a formed after using the resist pattern 3a as a core pattern, or the hard mask pattern 2a. This is also reflected in the uneven mold pattern 1a of the substrate 1 to be formed. For this reason, it is possible to produce an imprint mold which is a final product including the mold pattern 1a having a better dimensional variation in the uneven pattern than in the first embodiment.

<Modifications>
The technical scope of the present invention is not limited to the above-described embodiments, and includes various modifications and improvements as long as the specific effects obtained by the constituent elements of the invention and combinations thereof can be derived.

  With respect to the substrate 1, there is no material limitation as long as the material satisfies the mechanical strength required for the imprint mold. For example, in addition to the quartz substrate exemplified in the above embodiment, a glass material such as soda lime glass or aluminosilicate glass, or a resin film (sheet) may be used. As long as it is a mold for optical imprinting, it is sufficient if it can transmit light with a wavelength sufficient to cure the imprint resist (that is, photocurable resin). In addition, it is possible to use materials other than glass materials, for example, metal materials such as silicon, ceramic materials, or a composite thereof. The non-transparent material can be used as a mold for thermal imprinting or room temperature imprinting. In particular, a glass material is suitable as a substrate material because it can be processed with very high accuracy and is excellent in flatness and smoothness.

  The material constituting the hard mask layer 2 and the material constituting the mask layer 4 can be arbitrarily changed as long as the above-described imprint mold manufacturing method can be performed.

  The material constituting the resist layer 3 used in the electron beam direct writing method is not limited to the polymer type resist, but may be a chemical amplification type resist, an inorganic resist, or the like that has a practical sensitivity to the electron beam. For example, the selection can be arbitrarily changed.

  The imprint resist used in the imprint method is limited to a photo-curing resin when the photoimprint method is used, but in the case of thermal imprint or room temperature imprint, the imprint necessary for each imprint technique is used. The printing resist can be arbitrarily selected and changed.

  In the first embodiment, the removal of the mask pattern 4a and the etching of the substrate 1 are performed in a lump (one etching) from (A) to (B) in FIG. 4A, after the hard mask pattern 2a is formed by etching the hard mask layer 2, the mask pattern 4a is removed, and then the substrate 1 can be etched using the hard mask pattern 2a. .

  In the first embodiment and the second embodiment, the double patterning method is adopted. However, in the present invention, as an application example, a process related to double patterning is substantially performed three times. By repeating the above, the resist pattern may be formed with a wide pitch corresponding to a multiple of the desired pattern pitch. Moreover, in the said 1st Embodiment and 2nd Embodiment, although SADP method is used as a double patterning method, unless the effect of invention is impaired, it is not limited to this.

  The imprint mold obtained by the production method according to the present invention is not limited in its application, and can be used or applied in various fields.

DESCRIPTION OF SYMBOLS 1 ... Substrate 1a ... Mold pattern 2 ... Hard mask layer 2a ... Hard mask pattern 3 ... Resist layer 3a ... Resist pattern 4 ... Mask layer 4a ... Mask pattern 5 ... Intermediate mold 5a ... Uneven pattern

Claims (5)

A substrate constituting the imprint mold, at least a hard mask layer on the main surface thereof, and a resist layer formed thereon, and a predetermined treatment on the resist layer, thereby forming a resist pattern at a desired predetermined pitch. A first step of forming;
A second step of forming a mask pattern at a pitch narrower than the pitch of the resist pattern on the hard mask layer by a self-aligned double patterning method using the resist pattern as a core pattern;
A hard mask pattern is formed by etching the hard mask layer using the mask pattern, and an uneven pattern is formed on the main surface of the substrate by etching the substrate using the hard mask pattern. 3 steps,
A method for producing an imprint mold, comprising: The predetermined process of the first step is an electron beam direct writing method in which a resist layer is exposed by an electron beam to draw a pattern, and then a development process is performed to form a resist pattern. 2. A method for producing an imprint mold according to 1. 2. The imprint according to claim 1, wherein the predetermined process in the first step is performed by an imprint method in which an imprint mold having an uneven pattern on a main surface of a substrate is pressed against the resist layer. Method for manufacturing mold. The method for producing an imprint mold according to claim 1, 2 or 3, further comprising a step of narrowing a width of the resist pattern between the first step and the second step. The first step includes
Forming a hard mask layer and a resist layer in order on the main surface of the substrate;
Forming a resist pattern by applying a predetermined treatment to the resist layer,
The second step includes
Forming a mask layer in a state of covering an upper surface and side surfaces of the resist pattern and an exposed surface of the hard mask layer not covered with the resist pattern;
Etching the mask layer so that the upper surface of the resist pattern is exposed, thereby leaving a part of the mask layer as the mask pattern on both side surfaces of the resist pattern. The manufacturing method of the mold for imprint of Claim 1, 2 or 3.

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