JP6642689B2 - Imprint template and imprint method - Google Patents

Description

  The present invention relates to an imprint template and an imprint method used for nanoimprint lithography for transferring a fine transfer pattern to a resin formed on a transfer substrate.

  In recent years, in semiconductor lithography, the limitations of photolithography have been pointed out due to problems with exposure wavelengths and manufacturing costs in response to the demand for miniaturization of devices, and nanoimprint lithography using nanoimprint technology has (NIL: Nanoimprint Lithography) is attracting attention.

  In nanoimprint lithography, an imprint template (also referred to as a mold, stamper, or mold) having a finely patterned transfer pattern formed on its surface is brought into contact with a resin formed on a substrate to be transferred, such as a semiconductor wafer, The surface of the resin is molded into a concavo-convex shape of a transfer pattern of an imprint template, and then released, and then an excess portion (remaining film portion) is removed by dry etching or the like to obtain a transfer-receiving substrate. (For example, Patent Documents 1 and 2).

  In this nanoimprint lithography, once a template for imprint is prepared, a transfer pattern having a fine uneven shape can be repeatedly transferred and molded. Since this transfer step does not use an expensive exposure apparatus (stepper), it is economically advantageous. It is.

  In order to transfer the transfer pattern of the imprint template to the resin of the transfer substrate with high positional accuracy by the nanoimprint lithography as described above, it is necessary to precisely position the imprint template and the transfer substrate. Generally, alignment is performed by optically detecting the alignment mark of the concavo-convex structure provided on the imprint template and the alignment mark provided on the transfer target substrate from the imprint template side. Do.

  FIG. 10 is a cross-sectional view showing an example of a conventional imprint template. As shown in FIG. 10, the imprint template 101 has a first concave structure 113 and a second concave structure 114 whose base 111 is dug down from the main surface 112. In the imprint template 101, the first concave structure 113 forms a transfer pattern, and the second concave structure 114 forms an alignment mark.

FIG. 11 is a process chart showing an example of a conventional method for manufacturing an imprint template.
In order to manufacture the imprint template 101, for example, as shown in FIG. 11, first, a hard mask layer 160 is formed on the main surface of the base material 111A (FIG. 11A), and then an electron beam is formed. A resist having a resist pattern portion 170a for forming the first concave structure 113 and a resist pattern portion 170b for forming the second concave structure 114 on the hard mask layer 160 using a plate making technique such as drawing. A pattern 170 is formed (FIG. 11B).

Next, a portion of the hard mask layer 160 exposed from the resist pattern 170 is etched to form a hard mask pattern portion 161a for forming the first concave structure 113 and a hard mask for forming the second concave structure 114. A hard mask pattern 161 having a pattern portion 161b is formed, and then the resist pattern 170 is removed (FIG. 11C).
Next, the portion of the base material 111A exposed from the hard mask pattern 161 is etched to form a first concave structure 113 and a second concave structure 114 (FIG. 11D). Is removed to obtain an imprint template 101 (FIG. 11E).

As described above, in forming the resist pattern 170, since the resist pattern portion 170a and the resist pattern portion 170b are formed in the same step by using a plate making technique such as electron beam lithography, the resist pattern portion 170a and the resist pattern portion 170b are formed. And the relative position accuracy with respect to can be made high.
Therefore, the relative position accuracy between the hard mask pattern portion 161a and the hard mask pattern portion 161b is also high, and the relative position accuracy between the first concave structure 113 and the second concave structure 114 is also high. Becomes

Further, as described above, since the first concave structure 113 and the second concave structure 114 are formed in the same etching step using the hard mask pattern 161 as an etching mask, their depths are usually the same. It will be. That is, as shown in FIG. 10, if the distance from the main surface 112 to the bottom surface of the first recessed structures 113 and H _11, the distance from the main surface 112 to the bottom surface of the second concave structure 114 was H ₁₂ , H ₁₁ and H ₁₂ are the same value.

Here, in order to use the imprint template 101 as described above to transfer the transfer pattern (first concave structure 113) to the resin of the transfer target substrate with high positional accuracy (that is, for alignment), When the main surface 112 of the imprint template 101 is brought into contact with the resin formed on the substrate to be transferred, not only the transfer pattern (the first concave structure 113) but also the alignment marks of the imprint template 101 are formed. The second concave structure 114 will also be filled with the resin.
When the second concave structure 114 is filled with the resin, the refractive index of the material (generally, synthetic quartz glass) constituting the base 111 of the imprint template 101 and the refractive index of the resin become Since the values are almost the same, there is a problem that it is difficult to optically identify the second concave structure 114, that is, to optically identify the alignment mark of the imprint template 101.

  As described above, the reason for bringing the imprint template 101 into contact with the resin on the transfer substrate for alignment is that the alignment was performed with the imprint template 101 away from the transfer substrate. This is because, when the imprint template 101 is later brought into contact with the resin on the substrate to be transferred, a positional shift (so-called lock deviation) occurs in the process of bringing the imprint template 101 into contact with the resin on the substrate to be transferred.

  To solve this problem, as shown in FIG. 12, a high refractive film 115 having a higher refractive index than the material forming the base 111 is formed on the bottom surface of the second concave structure 114. Even if the second concave structure 114 is filled with a resin, a method has been proposed that enables optical identification as an alignment mark of the imprint template 102 (for example, Patent Documents 3 and 4). ).

In order to manufacture the imprint template 102, for example, as shown in FIG. 13, first, the above-described imprint template 101 is prepared (FIG. 13A), and the main surface is formed using a technique such as sputtering. A high refractive film 115A is formed on the bottom surface of the first concave structure 113, and on the bottom surface of the second concave structure 114 (FIG. 13B).
Next, a resist film 182 is formed thereon, and the step substrate is pressed against the resist film 182 so that the thickness (H ₁₅ ) of the region where the second concave structure 114 is formed is reduced to the first concave structure 113. The resist film 182 is deformed so as to be thicker than the film thickness (H ₁₄ ) in the region where it is present (FIG. 13C).
Thereafter, the resist film 182 is dry-etched by a predetermined thickness to leave the resist film 182 only inside the second concave structure 114 (FIG. 13D).
Next, the high refraction film 115A exposed from the resist film 182 is removed by dry etching, and finally, the resist film 182 inside the second concave structure 114 is removed, and the bottom surface of the second concave structure 114 is removed. The imprint template 102 having the high refractive film 115 thereon is obtained (FIG. 13E).

JP 2004-504718 A JP-A-2002-93748 JP 2007-103915 A JP 2013-168604 A

However, as the transfer pattern becomes finer (that is, the opening width of the first concave structure 113 of the imprint template 102 decreases), the depth of the first concave structure 113 (that is, The distance H ₁₁ ) to the bottom surface of the first concave structure 113 also becomes shallower.
More specifically, at present, the opening width of the first concave structure 113 is about 20 nm and its depth is about 60 nm. However, when the opening width of the first concave structure 113 is further reduced, In such a fine concave structure, an aspect ratio of about 2 is a limit of a processing technique, and a depth thereof is, for example, 40 nm or less.
As described above, in the conventional manufacturing method shown in FIG. 11, the depth of the first recessed structures 113 of imprint templates 102 and (H ₁₁₎ of the second recessed structures 114 depth (H ₁₂₎ Has the same value, the depth (H ₁₂ ) of the second concave structure 114 also becomes shallow (for example, 40 nm or less).

On the other hand, the thickness (H ₁₃ ) of the high-refractive-index film 115 currently needs to be about 15 nm to enable optical identification, but the depth (H ₁₃ ) ₁₂ ), the thickness of the resist film 182 shown in FIG. 13D also becomes thin, and the resist film 182 disappears in the step of dry-etching and removing the high refractive film 115A exposed from the resist film 182. Also, the high refractive film 115 on the bottom surface of the second concave structure 114 cannot have a required film thickness.
Therefore, even in the imprint template 102, it is difficult to optically identify the alignment mark, and there is a problem that high-precision alignment cannot be performed.

  The present invention has been made in view of the above circumstances, and even if the transfer pattern of the imprint template is miniaturized, high-precision alignment is possible, and the transfer pattern is accurately positioned on the resin of the substrate to be transferred. A main object is to provide an imprint template that enables transfer.

That is, the invention according to claim 1 of the present invention is an imprint template having a first concave structure and a second concave structure whose bases are dug down from the main surface, wherein the first surface is formed from the main surface. the distance to the bottom surface of the concave structure and H _1, the distance from the main surface to the bottom surface of the second concave structure when the H _2,
H ₂ > H ₁
Is a template for imprint, which satisfies the following relationship.

  Also, the invention according to claim 2 of the present invention is characterized in that a second material having a refractive index different from that of the first material forming the base is formed on the bottom surface of the second concave structure. The imprint template according to claim 1, wherein a material film is formed.

Further, the invention according to claim 3 of the present invention is characterized in that a distance from the main surface to the bottom surface of the second concave structure is H ₂ and a thickness of the second material film is H ₃ ,
H ₂ ≧ H ₃
3. The imprint template according to claim 2, wherein the following relationship is satisfied.

  In the invention according to claim 4 of the present invention, the second concave structure forms an alignment mark of the imprint template. It is a template.

The invention according to claim 5 of the present invention is characterized in that the imprint template optically aligns the second concave structure with an alignment mark provided on the transfer-receiving substrate, and An imprint template used in an imprint method for transferring a concave structure to a curable resin formed on the substrate to be transferred, wherein a distance from the main surface to a bottom surface of the first concave structure is H _1. and then, the distance from the main surface to the bottom surface of the second concave structure and H _2, the thickness of the second material layer and H _3, the wavelength of the detection light used for the optical alignment and lambda, The refractive index at the wavelength λ of the first material constituting the base portion is n ₁ , the refractive index at the wavelength λ of the second material constituting the second material film is n _2, and the wavelength λ of the curable resin is the refractive index before curing when the n ₃ in Stomach,
If n ₂ > n ₁ ,
2 × [{(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ } −H ₂ × n ₁ ] ≧ λ / 8
Satisfies the relationship
If n ₁ > n ₂ ,
2 × [H ₂ × n ₁ − {(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ }] ≧ λ / 8
The imprint template according to claim 3, wherein the relationship satisfies the following relationship:

The invention according to claim 6 of the present invention, the distance to the bottom surface of the first recessed structures and H ₁ from the main surface, the distance from the main surface to the bottom surface of the second concave structure H _2, and the thickness of the second material film is H ₃ ,
H ₂ −H ₁ ≧ H ₃
The imprint template according to any one of claims 3 to 5, wherein the following relationship is satisfied.

The invention according to claim 7 of the present invention has a first concave structure and a second concave structure in which a base is dug down from a main surface, and the base is provided on a bottom surface of the second concave structure. Using an imprint template on which a second material film made of a second material having a different refractive index from the first material forming the first material is formed, and a transfer substrate having an alignment mark. The second concave structure of the template is optically aligned with the alignment mark provided on the substrate to be transferred, and the first concave structure is transferred to the curable resin formed on the substrate to be transferred. a imprint method of the distance from the main surface of the imprint template to the bottom surface of the first recessed structures and H _1, the distance from the main surface to the bottom surface of the second recessed structures H ₂ , The thickness of the two-material film is H ₃ , the wavelength of the detection light used for the optical alignment is λ, the refractive index at the wavelength λ of the first material constituting the base is n _1, and the second material is In the case where the refractive index of the second material constituting the film at a wavelength λ is n ₂ and the refractive index of the curable resin before curing at a wavelength λ is n ₃ ,
If n ₂ > n ₁ ,
2 × [{(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ } −H ₂ × n ₁ ] ≧ λ / 8
Satisfies the relationship
If n ₁ > n ₂ ,
2 × [H ₂ × n ₁ − {(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ }] ≧ λ / 8
Is satisfied.

  ADVANTAGE OF THE INVENTION According to this invention, even if miniaturization of the transfer pattern of the template for imprint advances, highly accurate alignment with respect to a to-be-transferred substrate is possible, and a transfer pattern can be transferred to the resin of a to-be-transferred substrate with sufficient positional accuracy. it can.

Diagram for explaining imprint template 1 Diagram for explaining imprint template 2 FIG. 4 is a view for explaining an example of an imprint method according to the present invention. FIG. 6 is a view for explaining an example of alignment using the imprint template 2. FIG. 4 is a view for explaining an example of a resin pattern formed using the imprint template 2. The figure explaining an example of 1st Embodiment of the manufacturing method of the template 1 for imprints. FIG. 6 is a view for explaining an example of the first embodiment of the imprint template 1 following FIG. The figure explaining an example of 2nd Embodiment of the manufacturing method of the template 1 for imprints. FIG. 4 is a view for explaining an example of a method for manufacturing the imprint template 2. Sectional view showing an example of a conventional imprint template Process diagram showing an example of a method for manufacturing a conventional imprint template FIG. 4 is a diagram illustrating an imprint template 102. FIG. 4 illustrates an example of a method for manufacturing the imprint template 102.

  Hereinafter, the imprint template and the imprint method according to the present invention will be described in detail.

<Imprint template>
First, an imprint template according to the present invention will be described.
FIG. 1 is a diagram illustrating the imprint template 1, and FIG. 2 is a diagram illustrating the imprint template 2.
As shown in FIG. 1, the imprint template 1 has a first concave structure 13 and a second concave structure 14 in which a base 11 is dug down from a main surface 12, and a first concave structure 13 is formed from the main surface 12. the distance to the bottom surface of the concave structure 13 and H _1, when the distance from the main surface 12 to the bottom surface of the second concave structure 14 and the H _2, satisfies the relationship of H _2> H _1.

  By satisfying the above relationship, in the imprint template 2 manufactured from the imprint template 1, even if the transfer pattern is miniaturized, the second pattern formed on the bottom surface of the second concave structure 14 is formed. The two-material film 15 can be maintained at a required film thickness, high-precision alignment can be performed, and the transfer pattern can be transferred onto the resin of the transfer target substrate with high positional accuracy. The details will be described in the method for manufacturing an imprint template according to the present invention described later.

As shown in FIG. 2, the imprint template 2 is formed on the bottom surface of the second concave structure 14 from a second material having a different refractive index from the first material forming the base 11. A two-material film 15 is formed.
The imprint template 2 shown in FIG. 2 is manufactured from the above-described imprint template 1, which will be described in detail in the method for manufacturing an imprint template according to the present invention described below.
In the imprint template 2, the first concave structure 13 forms a transfer pattern, and the second concave structure 14 forms an alignment mark.

Here, the distance from the main surface 12 to the bottom surface of the second concave structure 14 and H _2, the thickness of the second material layer 15 in the case of the H _3, satisfy the relationship of H ₂ ≧ H ₃ Preferably, there is.
If there is a portion of the imprint template 2 that protrudes from the main surface 12, the thickness of the curable resin on the transfer target substrate corresponding to the protruding portion becomes thin during the imprint process. . This is because, when the substrate to be transferred having such a thinned resin portion is etched, the surface of the substrate to be transferred cannot be uniformly processed.
Therefore, it is preferable to satisfy the above relationship so that the second material film 15 does not protrude from the main surface 12.

The distance from the main surface 12 to the bottom surface of the first concave structure 13 is H ₁ , the distance from the main surface 12 to the bottom surface of the second concave structure 14 is H _2, and the thickness of the second material film 15 is Is H ₃ ,
H ₂ −H ₁ ≧ H ₃
Is preferably satisfied.
By satisfying the above relationship, even if the transfer pattern is miniaturized, the surface of the area where the alignment mark is formed on the transfer target substrate on which the pattern is transferred using the imprint template 2 is damaged. This is because that can be prevented. Details will be described in an imprint method according to the present invention described later.

<Imprint method>
Next, the imprint method according to the present invention will be described.
FIG. 3 is a diagram illustrating an example of an imprint method according to the present invention, FIG. 4 is a diagram illustrating an example of alignment using the imprint template 2, and FIG. FIG. 3 is a diagram illustrating an example of a resin pattern formed using a template 2.

  To transfer the transfer pattern composed of the first concave structure 13 to the curable resin 30 formed on the transfer substrate 20 using the imprint template 2, first, as shown in FIG. As shown, the main surface 12 of the imprint template 2 is disposed so as to face the curable resin 30 formed on the transfer substrate 20.

  Next, as shown in FIG. 3B, the imprint template 2 is brought into contact with the curable resin 30 formed on the transfer substrate 20 to form an alignment mark of the imprint template 2. The position information of the alignment mark 21 of the transferred substrate 20 facing the second concave structure 14 and the second concave structure 14 is detected by the detector 40 using the detection light 41, so that the imprint template 2 The alignment with the substrate to be transferred 20 is performed.

  The optical identification of the second concave structure 14 in the alignment step shown in FIG. 3B will be described in detail with reference to FIG.

  As shown in FIG. 4, when the imprint template 2 is brought into contact with the curable resin 30 for alignment, the curable resin 30 is filled in the second concave structure 14 of the imprint template 2.

Here, the main surface 12 adjacent to the second concave structure 14 and the second concave structure 14 including the second material film 15 are applied to the imprint template 2 from the back side (the side opposite to the main surface 12). The difference between the optical path lengths of the detection light beams 41a and 41b that enter and pass through the curable resin 30 and are reflected on the surface of the transfer substrate 20 is based on the fact that the wavelength of the detection light beams 41a and 41b is λ, 11, the refractive index at the wavelength λ of the first material constituting the second material film 15 is n ₁ , the refractive index at the wavelength λ of the second material constituting the second material film 15 is n ₂ , When the refractive index before curing is n ₃ and n ₂ > n ₁ ,
2 × [{(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ } −H ₂ × n ₁ ] ≧ λ / 8
become,
If n ₁ > n ₂ ,
2 × [H ₂ × n ₁ − {(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ }] ≧ λ / 8
become.

In order to obtain a contrast in a fine concavo-convex structure, the difference in the optical path length between the concave portion and the convex portion is important. It is possible enough.
Therefore, in imprint template 2,
If n ₂ > n ₁ ,
2 × [{(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ } −H ₂ × n ₁ ] ≧ λ / 8
Preferably satisfy the relationship
If n ₁ > n ₂ ,
2 × [H ₂ × n ₁ − {(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ }] ≧ λ / 8
It is preferable to satisfy the following relationship.

  As the second material forming the second material film 15, for example, a material containing at least one kind of a metal material and its oxide, nitride, oxynitride, or the like can be used. Specific examples of the above metal material include, for example, chromium (Cr), molybdenum (Mo), tantalum (Ta), tungsten (W), zirconium (Zr), titanium (Ti), and the like.

  In the nanoimprint lithography, an ultraviolet curable resin is often used as the curable resin 30, and the detection light 41a, 41b is light in a wavelength range where the above ultraviolet curable resin is not cured. Generally, a wavelength in the visible light range around 633 nm is used.

The refractive index of SiO ₂ , which is a general material of an imprint template, at a wavelength of 633 nm is 1.45. The refractive index of a curable resin used in an imprint method at a wavelength of 633 nm is generally Is about 1.5.

  Returning to FIG. 3, after the imprint template 2 and the transfer-receiving substrate 20 are aligned, as shown in FIG. After curing, the imprint template 2 is released from the mold to obtain a cured resin pattern 31 on the transfer substrate 20, as shown in FIG.

Here, as shown in FIG. 3D, the resin pattern 31 has a resin pattern portion 31a corresponding to the first concave structure 13 and a resin pattern portion 31b corresponding to the second concave structure 14. .
The height of the resin pattern portions 31a and 31b will be described in detail with reference to FIG.

As shown in FIG. 5, the imprint templates 2, if the distance from the main surface 12 to the bottom surface of the first recessed structures 13 is H _1, the convex of the resin pattern portion 31a corresponding to the first recessed structures 13 the height of the parts also becomes H _1.
Similarly, in the imprint templates 2, from the main surface 12 a distance to the bottom surface of the second concave structure 14 is a H _2, the thickness of the second material layer 15 formed on the bottom surface In the case of H ₃ , the height of the convex portion of the resin pattern portion 31b corresponding to the second concave structure 14 is (H ₂ −H ₃ ).

Therefore, if H ₁ , H ₂ , and H ₃ satisfy the relationship of H ₂ −H ₁ ≧ H ₃ , then H ₂ −H ₃ ≧ H ₁ , which corresponds to the second concave structure 14. The height (H ₂ −H ₃ ) of the resin pattern portion 31 b is higher than the height (H ₁ ) of the resin pattern portion 31 a corresponding to the first concave structure 13.
Therefore, when the transfer target substrate 20 is etched using a resin pattern satisfying the above relationship, the protrusion of the resin pattern portion 31a corresponding to the first concave structure 13 constituting the transfer pattern of the imprint template 2 is formed. Earlier, the protrusion of the resin pattern portion 31b corresponding to the second concave structure 14 constituting the alignment mark of the imprint template 2 does not disappear.

Here, when etching the transferred substrate 20, it is usual to end the etching before the convex portion of the resin pattern portion 31 a corresponding to the first concave structure 13 constituting the transfer pattern disappears. It is.
Therefore, when the transfer substrate 20 is etched using a resin pattern that satisfies the above relationship, the second concave structure 14 forming the alignment mark of the imprint template 2 is completed at the end of the etching process. Therefore, the protrusion of the resin pattern portion 31b corresponding to the above remains, and it is possible to prevent the surface of the area of the transfer substrate 20 where the alignment mark 21 is formed from being etched and damaged.

<Method of manufacturing imprint template>
Next, a method for manufacturing the imprint template will be described.
6 and 7 are diagrams illustrating an example of the first embodiment of the method of manufacturing the imprint template 1, and FIG. 8 is an example of the second embodiment of the method of manufacturing the imprint template 1. FIG. 9 is a diagram illustrating an example of a method of manufacturing the imprint template 2.

(Method of manufacturing imprint template 1)
(First embodiment)
First, a method for manufacturing the imprint template 1 will be described.
In order to manufacture the imprint template 1, for example, as shown in FIG. 6, first, a hard mask layer 60 is formed on the main surface of the substrate 11A (FIG. 6A), and then the electron beam is formed. A resist having a resist pattern portion 70a for forming the first concave structure 13 and a resist pattern portion 70b for forming the second concave structure 14 on the hard mask layer 60 using a plate making technique such as drawing. A pattern 70 is formed (FIG. 6B).

  Next, a portion of the hard mask layer 60 exposed from the resist pattern 70 is etched to form a hard mask pattern portion 61a for forming the first concave structure 13 and a hard mask for forming the second concave structure 14. A hard mask pattern 61 having a pattern portion 61b is formed, and then the resist pattern 70 is removed (FIG. 6C).

  Next, a thick resist film 81 is locally formed on the region of the hard mask pattern portion 61a, and the base material 111A exposed from the opening of the hard mask pattern portion 61a is covered with the resist film 81 (FIG. d)). In the step shown in FIG. 6D, the base material 11A is exposed from the opening of the hard mask pattern portion 61b.

Then, a predetermined amount of base 11A of the portion exposed from the opening of the hard mask pattern portion 61b (i.e., H ₂ -H ₁ equivalent) is etched (FIG. 7 (e)), then, removing the resist film 81 (FIG. 7F).

Then, a predetermined amount of base 11A of the portion exposed from the hard mask pattern 61 (i.e., H ₁ equivalent) is etched to form a first recessed structures 13 and the second recessed structures 14 (FIG. 7 ( g)) Then, the hard mask pattern 61 is removed to obtain the imprint template 1 (FIG. 7 (h)).

As described above, by using the resist film 81 of a thick film, the distance from the main surface 12 to the bottom surface of the first recessed structures 13 and H _1, from the main surface 12 to the bottom surface of the second recessed structures 14 distance when the H _2, it is possible to manufacture the imprint template 1 having a first recessed structures 13 satisfy the relationship of H _2> H ₁ and the second recessed structures 14.

Here, as shown in FIG. 6B, in forming the resist pattern 70, the resist pattern portion 70a and the resist pattern portion 70b are formed in the same step by using a plate making technique such as electron beam drawing. The relative positional accuracy between the pattern portion 70a and the resist pattern portion 70b can be made high.
Therefore, the relative positional accuracy between the hard mask pattern portion 61a and the hard mask pattern portion 61b is also high, and the relative positional accuracy between the first concave structure 13 and the second concave structure 14 is also high. It can be.

(Second embodiment)
Next, another example of the method for manufacturing the imprint template 1 will be described with reference to FIG. The manufacturing method according to the second embodiment utilizes the phenomenon that the etching rate of the base material 11A is improved by ion implantation.

  In order to manufacture the imprint template 1 according to the present embodiment, first, ions are locally applied to a region where the second concave structure 14 is formed from above the main surface of the base material 11A using an ion implantation apparatus. Inject 90. The acceleration energy of the implanted ions is used in a range of about 10 keV to 1 MeV (FIG. 8A).

  As described above, by locally implanting the ions 90 into the region where the second concave structure 14 is to be formed, the etching rate of the substrate 11A in this region is reduced to the substrate 11A in the region where the ions 90 are not implanted. Higher than the etching rate of

  The elements of the ions used for the ion implantation are not particularly limited, but phosphorus (P), antimony (Sb), nitrogen (N), boron (B), aluminum (Al), gallium, which have been used for semiconductors. (Ga), indium (In), silicon (Si), lead (Pb), argon (Ar), xenon (Xe) and the like are preferable.

The dose of the implanted ions is preferably in the range of about 5 × 10 ¹⁰ ions / cm ² to 1 × 10 ¹⁸ ions / cm ² . If it is less than 5 × 10 ¹⁰ ions / cm ² , the effect of improving the etching rate is small, while if it exceeds 1 × 10 ¹⁸ ions / cm ² , the transmittance of the base 11 may be reduced.

Next, a hard mask pattern portion 61a for forming the first concave structure 13 and a hard mask pattern for forming the second concave structure 14 are formed on the main surface of the base material 11A into which the ions 90 are locally implanted. A hard mask pattern 61 having a mask pattern portion 61b is formed (FIG. 8B).
Note that the hard mask pattern 61 shown in FIG. 8B can be formed in the same manner as in the above-described steps of FIGS. 6A to 6C, and a description thereof will be omitted.

  Next, a predetermined amount of the base material 11A exposed from the hard mask pattern 61 is etched to form a first concave structure 13 and a second concave structure 14 (FIG. 8C). The pattern 61 is removed to obtain the imprint template 1 (FIG. 8D).

As described above, by locally injecting the ions 90 into the hard mask pattern portion 61b, the etching rate of the base material 11A exposed from the opening of the hard mask pattern portion 61b is increased from the opening of the hard mask pattern portion 61a. It becomes faster than the etching rate of the exposed substrate 11A.
Thus, by controlling the dose amount of the implanted ions, as shown in FIG. 8 (d), the distance from the main surface 12 to the bottom surface of the first recessed structures 13 and H _1, second from the main surface 12 the distance to the bottom surface of the second concave structure 14 when the H _2, H _2> satisfy the relationship of H _1, producing the imprint template 1 having a first recessed structures 13 and the second recessed structures 14 can do.

  Here, in the above-described first embodiment, in order to form the first concave structure 13 and the second concave structure 14, an etching process shown in FIG. 7E and a process shown in FIG. Although two etching steps of the etching step were required, in the second embodiment, the etching step for forming the first concave structure 13 and the second concave structure 14 is the same as that shown in FIG. One etching step shown in c) is sufficient. Therefore, in the second embodiment, the number of manufacturing steps can be shorter than that in the first embodiment.

  Since the hard mask pattern 61 shown in FIG. 8B can be formed in the same manner as in the steps of FIGS. 6A to 6C in the first embodiment, it is the same as in the first embodiment. In addition, the relative positional accuracy between the hard mask pattern portion 61a and the hard mask pattern portion 61b can be made high. Therefore, the relative positional accuracy between the first concave structure 13 and the second concave structure 14 can be made high.

(Method of manufacturing imprint template 2)
Next, a method for manufacturing the imprint template 2 will be described.
In order to manufacture the imprint template 2, for example, as shown in FIG. 9, first, the above-described imprint template 1 is prepared (FIG. 9A), and the main surface is formed using a method such as a sputtering method. 12, a second material film 15A is formed on the bottom surface of the first concave structure 13 and on the bottom surface of the second concave structure 14 (FIG. 9B).

Next, a resist film 82 is formed thereon, and the stepped substrate is pressed against the resist film 82 so that the thickness (H ₅ ) of the region where the second concave structure 14 is formed is reduced to the first concave structure 13. The resist film 82 is deformed so as to be thicker than the film thickness (H ₄ ) in the region where it is present (FIG. 9C).
Thereafter, a predetermined thickness of the resist film 82 (H ₅ or more thick) by dry etching, a state where only the inside resist film 82 remains in the second recessed structures 14 (FIG. 9 (d)).

Here, a distance H ₁ from the main surface 12 to the bottom surface of the first concave structure 13, a film thickness H _{4 in} a region where the first concave structure 13 is formed, and a second concave structure 14 are formed. relationship thickness H ₅ regions, so long as it satisfies the _{H 5 ≧ H 4 + H 1} , as shown in FIG. 9 (d), the second material layer 15A are all formed on the major surface 12 The thickness of the resist film 82 that is exposed from the resist film 82 and does not remain inside the first concave structure 13 and remains inside the second concave structure 14 is H it is possible to realize a state where _two.

  Next, the second material film 15A exposed from the resist film 82 is removed by dry etching, and finally, the resist film 82 inside the second concave structure 14 is removed, and the bottom surface of the second concave structure 14 is removed. To obtain an imprint template 2 having a second material film 15 thereon (FIG. 9E).

As described above, the imprint template 2 is manufactured from the imprint template 1. In the imprint template 1, the depth (H ₂ ) of the second concave structure 14 is set to the first concave structure 13. (H ₁ ).
Therefore, as the transfer pattern becomes finer (that is, the opening width of the first concave structure 13 of the imprint template 2 is reduced), the depth (H ₁ ) of the first concave structure 13 is reduced. Even if it becomes shallower (for example, 40 nm or less), the depth (H ₂ ) of the second concave structure 14 can be made the same as the conventional depth (for example, 60 nm).

  Therefore, the thickness of the resist film 82 shown in FIG. 9D can be made the same as the conventional thickness (for example, 60 nm). Therefore, the second material film 15A exposed from the resist film 82 is dry-etched. Even after the removal step, the resist film 82 can be left in the second concave structure 14 as in the related art.

  Therefore, the film thickness of the second material film 15 on the bottom surface of the second concave structure 14 can remain the same as the conventional film thickness (for example, 15 nm). The thickness of the second material film 15 is such that even when the second concave structure 14 is filled with resin in the pattern transfer using the imprint template 2, the second concave structure 14 is aligned. This is a film thickness that can be optically identified as a mark.

  Therefore, even when the transfer pattern is miniaturized, high-precision alignment can be performed in pattern transfer using the imprint template 2.

  As above, the imprint template and the imprint method according to the present invention have been described, but the present invention is not limited to the above embodiment. The above embodiment is an exemplification, and those having substantially the same configuration as the technical idea described in the claims of the present invention and exerting the same operation and effect in any case are the present invention. It is included in the technical scope of the invention.

1, 2 Imprint template 11 Base 11A Base 12 Main surface 13 First concave structure 14 Second concave structure 15, 15A Second material film 20 Transferred substrate 21 Alignment mark 30 Curable resin 31 Resin pattern 31a, 31b Resin pattern part 40 Detector 41, 41a, 41b Detection light 50 Ultraviolet ray 60 Hard mask layer 61 Hard mask pattern 61a, 61b Hard mask pattern part 70 Resist pattern 70a, 70b Resist pattern part 81, 82 Resist film 90 Ion 101, 102 Imprint template 111 Base 111A Base 112 Main surface 113 First concave structure 114 Second concave structure 115, 115A High refractive film 120 Transfer receiving substrate 121 Alignment mark 132a, 132b Resin pattern 160 Domasuku layer 161 hard mask pattern 161a, 161b hard mask pattern portion 170 a resist pattern 170a, 170b resist pattern 182 resist film

Claims (3)

An imprint template having a first concave structure and a second concave structure whose base is dug down from the main surface,
The first concave structure forms a transfer pattern of the imprint template,
The second concave structure forms an alignment mark of the imprint template,
An opening width of the first concave structure includes a pattern smaller than 20 nm;
A second material film made of a second material having a different refractive index from the first material forming the base is formed on the bottom surface of the second concave structure,
The distance to the bottom surface of the first recessed structures and H ₁ from the main surface,
The distance from the main surface to the bottom surface of the second concave structure is H ₂ ,
When the thickness of the second material film is H ₃ ,
H ₂ > H ₁
And H ₂ ≧ H ₃
And
H ₂ −H ₁ ≧ H ₃
Satisfies the relationship
The first material constituting the base includes SiO ₂ ,
The second material forming the second material film is a metal material containing any one of chromium (Cr), molybdenum (Mo), tantalum (Ta), tungsten (W), and zirconium (Zr); or And an oxide, nitride, or oxynitride of the metal material. The imprint template,
Imprinting for optically aligning the second concave structure with an alignment mark provided on the transferred substrate and transferring the first concave structure to a curable resin formed on the transferred substrate. An imprint template used in the method,
The distance from the main surface to the bottom surface of the first recessed structures and H _1, the distance to the bottom surface of the second concave structure and H ₂ from the main surface, the thickness of the second material film H ₃ and
The wavelength of the detection light used for the optical alignment is λ,
The refractive index at a wavelength λ of the first material constituting the base is n ₁ ,
The refractive index at the wavelength λ of the second material constituting the second material film is n ₂ ,
In the case where the refractive index of the curable resin before curing at a wavelength λ is n ₃ ,
n ₂ > n ₁ , and
2 × [{(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ } −H ₂ × n ₁ ] ≧ λ / 8
The imprint template according to claim 1, wherein the following relationship is satisfied. 3. The imprint template according to claim 1 or 2, and a transfer substrate having an alignment mark, wherein the second concave structure of the imprint template and an alignment mark provided on the transfer substrate are used. Optically aligning and transferring the first concave structure to a curable resin formed on the transfer-receiving substrate,
The distance from the main surface of the imprint template to the bottom surface of the first recessed structures and H _1, the distance from the main surface to the bottom surface of the second concave structure and H _2, the second material Let the film thickness be H ₃ ,
The wavelength of the detection light used for the optical alignment is λ,
The refractive index at a wavelength λ of the first material constituting the base is n ₁ ,
The refractive index at the wavelength λ of the second material constituting the second material film is n ₂ ,
In the case where the refractive index of the curable resin before curing at a wavelength λ is n ₃ ,
n ₂ > n ₁ , and
2 × [{(H ₂ −H ₃ ) × n ₃ + H ₃ × n ₂ } −H ₂ × n ₁ ] ≧ λ / 8
An imprint method characterized by satisfying the following relationship :

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