JP6421425B2 - Template substrate manufacturing method and nanoimprint template manufacturing method - Google Patents

Description

  The present invention relates to the technical field of nanoimprint, and in particular, a method for producing a template substrate having a flat work surface from a template for nanoimprint having a pattern-formed surface on which an uneven transfer pattern is formed, and The present invention relates to a method for newly manufacturing a template for nanoimprint from the template substrate.

  In recent years, in semiconductor lithography, the limit of the photolithography method has been pointed out due to the problem of exposure wavelength and manufacturing cost in response to the demand for miniaturization of devices. As a countermeasure, nanoimprint lithography using nanoimprint technology has been pointed out. (NIL: Nanoimprint Lithography) is drawing attention.

In nanoimprint lithography, a template (also referred to as a mold, stamper, or mold) on which a fine uneven transfer pattern is formed is brought into contact with an imprint material formed on a transfer substrate such as a semiconductor wafer. The surface of the imprint material is molded into a concavo-convex shape of the template transfer pattern, then released, and then the excess part (residual film part) is removed by dry etching, etc. This is a technique for transferring the concave / convex shape of the template transfer pattern (more specifically, the concave / convex inverted shape) to the imprint material (for example, Patent Documents 1 and 2).
In this nanoimprint lithography, once a template (also referred to as a template for nanoimprinting as appropriate) is prepared, a transfer pattern with fine irregularities can be repeatedly transferred and molded, and an expensive exposure device (stepper) is not used for this transfer process. It is also economically advantageous.

  Conventionally, as shown in FIG. 8, the template 110 has a mesa-like convex structure 113 having a pattern formation surface 111 on which a transfer pattern 112 is formed on the surface side (first side 110 a). There are forms. If it is such a form, it can suppress that parts other than the pattern formation surface 111 of the template 110 contact with a to-be-transferred substrate and imprint material in an imprint process.

  Further, there is a form in which a concave structure 114 is formed on the back side (second side 110b) of the template 110 so as to include the convex structure 113 in a plan view. (For example, patent document 3). If it is such a form, it can suppress that a bubble remains between the template 110 and imprint material by curving the pattern formation surface 111 of the template 110 in an imprint process, and a template. The mold 110 and the imprint material can be easily released from each other.

JP-T-2004-504718 JP 2002-93748 A Special table 2009-536591

Here, as the template substrate, an expensive substrate having a work surface adjusted with high precision in terms of flatness, roughness, etc. is used in order to transfer a fine transfer pattern to the transfer substrate side. . Typically, as a template substrate, a substrate made of synthetic quartz glass is mainly used in the same manner as a substrate used for a photomask, but it is more expensive than other materials.
Further, when the substrate has a mesa-like convex structure as described above or a concave structure on the back side, the substrate including the manufacturing cost becomes more expensive.

On the other hand, the uneven transfer pattern formed on the template for nanoimprint generally requires a size (width dimension) of 1/4 or less than the mask pattern formed on a conventional photomask, and further processing in the depth direction. Since accuracy is also required, in the manufacture of nanoimprint templates, transfer pattern shapes and defects are more likely to occur than in conventional photomask manufacturing.
Therefore, in order to reduce the manufacturing cost, it is required to regenerate the template substrate by removing the uneven transfer pattern from the defective nanoimprint template.

Here, as a method of removing the uneven transfer pattern from the defective nanoimprint template, for example, a polishing slurry is used as a pattern forming surface of the nanoimprint template (surface on which the uneven transfer pattern is formed). A method of polishing by pressing a surface plate to which a polishing pad made of urethane or the like is affixed can be considered.
This polishing process includes a primary polishing process using a polishing slurry mainly composed of cerium oxide having a relatively large particle size (about 0.3 to 3 μm) and a relatively small particle size (about 10 to 300 nm). And a secondary polishing treatment using a polishing slurry containing colloidal silica.

However, if the fine uneven pattern of the nanoimprint template is removed by the polishing method including the first polishing process and the second polishing process as described above, the nanoimprint template is cracked or chipped by the first polishing process. May occur.
In particular, in a template having a concave structure on the back side, since the thickness of the portion where the concave structure is formed is thinner than other portions, stress is applied to the boundary between the thin portion and the thick portion, cracks and There is a risk of chipping and the like.
Further, in the polishing method as described above, the area near the edge of the upper surface of the mesa-shaped convex structure is polished more than the central area of the upper surface by the first polishing process, and the upper surface of the convex structure is flattened. There is also a problem that it is difficult to form on a smooth surface.

  In general, the concavo-convex shape transfer pattern of the nanoimprint template has a height (depth) of about several tens of nanometers, but the transfer pattern is to be removed only by the secondary polishing process in the polishing process as described above. However, although the height (depth) of the concavo-convex shape of the transfer pattern is somewhat reduced, it is extremely difficult to completely remove the transfer pattern. The reason why the transfer pattern cannot be completely removed only by the secondary polishing treatment is not certain, but silica particles with a relatively small particle size contained in the colloidal silica as the polishing slurry enter the fine concavo-convex pattern. Therefore, it is considered that the chemical polishing action by the silica particles works in the recesses of the fine uneven pattern, and the recesses are polished.

  The present invention has been made in view of the above circumstances, and is flat from a nanoimprint template having a pattern-formed surface on which a concavo-convex transfer pattern is formed while preventing the occurrence of cracks and chips as described above. An object of the present invention is to provide a technique for reclaiming a template substrate having a work surface and making it usable for producing a new nanoimprint template.

  As a result of various studies, the inventor formed a coating filler layer on the pattern forming surface of the template, formed a planarization layer thereon, and the thickness until the planarization layer and the coating filler layer disappeared. The present invention has been completed by finding that the above problem can be solved by etching in the direction.

  That is, the invention according to claim 1 of the present invention is a method for manufacturing a template substrate having a flat work surface from a nanoimprint template having a pattern-formed surface on which an uneven transfer pattern is formed, A preparation step of preparing a template for nanoimprint, a covering filler layer forming step of forming a covering filler layer on the pattern formation surface so as to cover the pattern formation surface and be filled in the transfer pattern; A planarization layer forming step of forming a planarization layer on the coating filler layer by supplying an imprint material on the coating filler layer and bringing a planarizing member having a planar surface into contact with the imprint material. And a processed surface that forms the processed surface by etching in the thickness direction until the planarizing layer and the covering filler layer disappear. And forming step, a method for producing a template substrate, characterized by sequentially comprising a.

  In the invention according to claim 2 of the present invention, the ratio of the etching rate in the thickness direction of the covering filler layer to the etching rate in the thickness direction of the planarizing layer is 1 or less in the processing surface forming step. The etching is performed under the condition that the ratio of the etching rate in the thickness direction of the material constituting the pattern forming surface of the template to the etching rate in the thickness direction of the coating filler layer is 1 or less. A method for manufacturing a template substrate according to claim 1.

  In the invention according to claim 3 of the present invention, the ratio of the etching rate in the thickness direction of the covering filler layer to the etching rate in the thickness direction of the planarizing layer in the process surface forming step is 0.9. The value is 1.1 or less, and the ratio of the etching rate in the thickness direction of the material constituting the pattern forming surface of the template to the etching rate in the thickness direction of the coating filler layer is 0.9 or more and 1.1 or less. The method for manufacturing a template substrate according to claim 1, wherein etching is performed under conditions that result in a value.

  In the invention according to claim 4 of the present invention, the work surface forming step includes a first etching step of etching in the thickness direction until the planarizing layer disappears, and the covering filler layer comprises It is a manufacturing method of the template substrate as described in any one of Claims 1-3 including the 2nd etching process of etching in the thickness direction until it lose | disappears.

  In the invention according to claim 5 of the present invention, the covering filler layer forming step is a film forming step using an atomic layer deposition method, wherein the covering filler layer formed by the atomic layer deposition method is formed. 5. The method for manufacturing a template substrate according to claim 1, wherein the thickness is not less than ½ of the opening size of the concave portion of the transfer pattern.

  In the invention according to claim 6 of the present invention, the nanoimprint template has a first side on which the transfer pattern is provided, and a second side facing the first side, 6. The template substrate manufacturing method according to claim 1, wherein a mesa-like convex structure having the pattern forming surface as a main surface is formed on the first side. 7. is there.

  In the invention according to claim 7 of the present invention, the nanoimprint template has a first side on which the transfer pattern is provided, and a second side facing the first side, The template substrate manufacturing method according to claim 1, wherein a concave structure is formed on the second side.

  The invention according to claim 8 of the present invention is characterized in that a new transfer pattern is formed on a work surface of a template substrate manufactured by the method for manufacturing a template substrate according to claims 1 to 7. It is a manufacturing method of a template.

According to the method for producing a template substrate of the present invention, a flat work surface from a nanoimprint template having a pattern forming surface on which a concavo-convex transfer pattern is formed while preventing the occurrence of cracks and chips as described above. A template substrate having the following can be manufactured.
Moreover, according to the method for manufacturing a template for nanoimprinting of the present invention, the manufacturing cost of the template for nanoimprinting can be kept low by using the regenerated template substrate.

It is a schematic process drawing which shows an example of the manufacturing method of the template board | substrate which concerns on this invention. It is explanatory drawing which shows an example of the formation method of the covering filler layer which concerns on this invention. It is a schematic process drawing which shows an example of the formation method of the planarization layer which concerns on this invention. It is explanatory drawing which shows the process in which the surface of a coating filler layer is planarized. It is explanatory drawing which shows the process in which a flat to-be-processed surface is formed. It is a process flowchart which shows an example of the manufacturing method of the template board | substrate which concerns on this invention. It is a schematic process drawing which shows an example of the manufacturing method of the template for nanoimprint which concerns on this invention. It is explanatory drawing which shows an example of the template for nanoimprint, (a) is a schematic plan view, (b) is AA sectional drawing in (a). It is explanatory drawing which shows the other example of the template for nanoimprints.

  Hereinafter, a method for producing a template substrate according to the present invention and a method for producing a nanoimprint template according to the present invention will be described.

<Template substrate manufacturing method>
First, a method for manufacturing a template substrate according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic process diagram showing an example of a template substrate manufacturing method according to the present invention.
The template substrate manufacturing method according to the present invention has, for example, a flat processed surface 2 from a nanoimprint template 10 having a pattern forming surface 11 on which an uneven transfer pattern 12 is formed, as shown in FIG. A method of manufacturing a template substrate 1, which includes a preparation step of preparing a template 10 for nanoimprint (FIG. 1A), pattern formation so as to cover the pattern formation surface 11 and fill the transfer pattern 12 A coating filler layer forming step of forming the coating filler layer 21 on the surface 11 (FIG. 1B), supplying an imprint material on the coating filler layer 21, and the imprint material having a flat surface; A flattening layer forming step of forming a flattening layer 31 on the covering filler layer by contacting the flattening member (FIG. 1C); To a fine coating filler layer 21 disappears, and the processed surface forming step by etching in the thickness direction to form a treated surface 2 (Figure 1 (d)), in which sequentially comprises a.

  As described above, in the present invention, a primary slurry using a polishing slurry mainly composed of cerium oxide having a relatively large particle size (about 0.3 to 3 μm) as used in the conventional polishing process. Since the polishing process is not included, even if the template has the above-described concave structure, stress is applied to the boundary between the thin part and the thick part, and cracks, chips, etc. are generated. Does not occur.

  In the present invention, since the first polishing process as described above is not included, the template has a mesa-like convex structure, and a pattern forming surface is formed on the upper surface of the convex structure. However, the area near the edge of the upper surface of the mesa-shaped convex structure is polished more than the central area of the upper surface, eliminating the problem that the upper surface of the convex structure cannot be formed on a flat work surface. can do.

  Further, in the conventional regenerating method by polishing including the first polishing process as described above, a polishing allowance of about several μm (for example, 4 μm) is required. However, in the present invention, the depth disappeared from the height position of the pattern forming surface of the initial template 10 is a concavo-convex shape transfer. Since it is possible to make it the same as the depth of the pattern (for example, 60 nm), the change in height can be suppressed to about 1/100 compared with the reproducing method by the conventional polishing.

Hereinafter, each process of the manufacturing method of the template board | substrate which concerns on this invention is demonstrated.
(Template preparation process)
In the present invention, as a template for nanoimprint to be prepared, a pattern forming surface 11 on which a concavo-convex shaped transfer pattern 12 composed of a concave portion 12A and a convex portion 12B is formed as in the template 10 shown in FIG. Any nanoimprint template can be used.

  For example, a template 110 shown in FIG. 8 has a first side 110a and a second side 110b opposite to the first side 110a, and a transfer pattern 112 is formed on the first side 110a. The mesa-like convex structure 113 having the pattern forming surface 111 as an upper surface is formed, and the concave structure 114 is formed on the second side 110b so as to include the convex structure 113 in plan view. Nanoimprint templates can be used.

  Further, in the present invention, as a template for nanoimprint to be prepared, a mesa-shaped convex structure 113 having a pattern formation surface 111 as an upper surface is formed on the first side 110a as in the template 210 shown in FIG. 9A. However, the template may be a nanoimprint template in which a concave structure is not formed on the second side 110b, and further, a mesa-shaped convex structure such as a template 211 shown in FIG. 9B. Also, the concave structure on the back surface side is not formed, and the surface of the first side 110a is a flat surface, and the uneven transfer pattern 112 is formed with this flat surface as the pattern forming surface 111. It may be a template for nanoimprint.

(Coating filler layer formation process)
Next, the process of forming the coating filler layer will be described.
As shown in FIG. 1B, in the method for manufacturing a template substrate according to the present invention, the inside of the recess 12 </ b> A that covers the pattern formation surface 11 and constitutes the transfer pattern 12 on the pattern formation surface 11 of the template 10. The covering filler layer 21 is formed so as to be filled.

The material constituting the covering filler layer 21 is the thickness direction (Z direction shown in FIG. 1) of the planarizing layer 31 formed on the covering filler layer 21 in the step of forming the work surface 2 described above. The ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction of the coating filler layer 21 to the etching rate (Ep) is
Ec / Ep ≦ 1
Satisfy the relationship
The ratio (Eb / Ec) of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the coating filler layer 21 is
Eb / Ec ≦ 1
It is preferable that the relationship is satisfied.
By repeating a series of the above-described covering filler layer forming step, planarizing layer forming step, etching step for eliminating the flattening layer 31, and etching step for eliminating the covering filler layer 21, a flat workpiece is processed. This is because the template substrate 1 having the surface 2 can be obtained.
The details of this relationship will be described in the process surface forming step described later.

In the present invention, the etching rate (Ep) in the thickness direction (Z direction shown in FIG. 1) of the planarization layer 31 formed on the coating filler layer 21 in the step of forming the work surface 2 described above. The ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction of the coating filler layer 21 with respect to
0.9 ≦ Ec / Ep ≦ 1.1
The ratio (Eb / Ec) of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the coating filler layer 21 is satisfied.
0.9 ≦ Eb / Ec ≦ 1.1
It may satisfy the relationship.

If the material constituting the covering filler layer 21 satisfies the above-described relationship, a processed surface having a generally desired flatness can be obtained in one step without performing the above-described repetitive steps. Because it can.
In this case, there is a concern that the flatness of the work surface to be obtained is inferior to the case where the above-described repeating process is performed. However, since only one process is required, the process can be shortened or manufactured. This is beneficial in terms of cost reduction.
For example, if the PV (Peak to Valley) value of the reproduced processing surface 2 is 10% or less of the uneven step of the original transfer pattern 12, it can be used as a reproduction template substrate.

  Here, since the material constituting the template 10 is mainly synthetic quartz glass, silicon oxide can be given as a specific example of what is included in the material constituting the covering filler layer 21.

As a method for forming the coating filler layer 21, a vacuum film formation method such as an atomic layer deposition method (ALD method: Atomic Layer Deposition method), a sputtering film formation method, a CVD (Chemical Vapor Deposition) film formation method, or an SOG ( For example, a spin on glass (Spin On Glass) material may be used.
Among these, the atomic layer deposition method is a technique that enables film formation in units of atomic layers, and is preferable in that a coating film having a uniform film thickness can be formed with high shape followability.

For example, when a silicon oxide (SiOx) film is formed using an atomic layer deposition method, a source gas containing silicon (Si) and a reaction gas containing oxygen (O) are used in the atomic layer deposition method. Can be formed.
Further, a gas containing a plurality of elements may be used as the reaction gas. For example, a silicon oxynitride (SiON) film is formed using a source gas containing silicon (Si) and a reaction gas containing oxygen (O) and nitrogen (N), or a source gas containing silicon (Si). A fluorine-containing silicon oxide film (SiOF) film can be formed using a reaction gas containing oxygen (O) and fluorine (F).

  In the template substrate manufacturing method according to the present invention, when the coating filler layer is formed by using the above-described atomic layer deposition method, the thickness of the coating filler layer formed by the atomic layer deposition method is the template transfer pattern. It is preferable that the size of the recess is not less than ½ of the opening size of the recess. This is because, by forming the covering filler layer so as to satisfy such a condition, the uneven transfer pattern can be reliably filled with the covering filler layer.

The above will be described in more detail with reference to FIG. For example, as shown in FIG. 2A, the thickness (T ₁ ) of the covering filler layer 21 formed using the atomic layer deposition method is 1 / W of the opening size (W) of the concave portion of the transfer pattern of the template 10. When the size is less than 2, the deposited film formed by the atomic layer deposition method has a high shape following ability, and therefore the side surface and the bottom surface of the recess have the same film thickness (T ₁ ). As a result, the inside of the recess is not completely filled, and a recess having an opening dimension of (W-2 × T ₁ ) is formed. End up.

On the other hand, as shown in FIG. 2B, the thickness (T ₂ ) of the covering filler layer 21 formed by using the atomic layer deposition method is 1 / W of the opening size (W) of the concave portion of the transfer pattern of the template 10. When the size is 2 or more, the coating filler layer 21 formed on the opposing side surfaces of the recesses increases in thickness as the film formation proceeds and eventually comes into contact with each other. The inside can be reliably filled with the coating filler layer 21.

(Planarization layer forming process)
Next, a process for forming the planarizing layer will be described.
As shown in FIG. 1 (c), in the template substrate manufacturing method according to the present invention, a planarizing layer 31 is formed on the coating filler layer 21.
When the sputter film forming method, the CVD method, or the spin coating method is used for forming the covering filler layer 21, the flatness of the surface of the formed covering filler layer 21 is usually inferior. It is necessary to form.

2 is mainly intended to explain the principle characteristics of film formation by atomic layer deposition, and therefore the surface of the covering filler layer 21 in FIG. In practice, however, the boundary where the coating filler layers 21 whose film thickness increases with the progress of film formation contact each other from the side surfaces facing each other in the concave portion, that is, the center of the concave portion. There is a possibility that a slight level difference (for example, a level difference of about several nm to 10 nm) may occur in the portion.
Therefore, even when the atomic layer deposition method is used to form the coating filler layer 21, the surface irregularities of the coating filler layer 21 including the above-described slight steps are absorbed to form a flatter surface. In addition, the planarization layer 31 is preferably formed.

  The process of forming the planarization layer according to the present invention will be described in more detail with reference to FIG. FIG. 3 is a schematic process diagram showing an example of a method for forming a planarization layer according to the present invention. In order to avoid complication, FIG. 3 shows the coating filler layer 21 according to the present invention. Only the configuration on the upper side (surface side) is shown, and the lower side of the coating filler layer 21 and the template 10 are not shown.

In the step of forming the planarization layer 31 according to the present invention, nanoimprint lithography technology is applied.
That is, first, a template on which the covering filler layer 21 is formed is prepared (FIG. 3A), and the imprint material 31a is supplied onto the covering filler layer 21 (FIG. 3B). The flat surface of the flattening member 40 is brought into contact with the print material 31a, so that the imprint material 31a is in a layered form with a flat upper surface (FIG. 3C).
Next, for example, the imprint material 31a is cured by a method of irradiating the ultraviolet ray 50 (FIG. 3D), and then the planarizing member 40 is released (FIG. 3E), and the covering filler A template in which the planarizing layer 31 is formed on the layer 21 is obtained.

  In addition, as a method for supplying the imprint material 31a onto the coating filler layer 21, various methods used in nanoimprint lithography can be used. For example, an inkjet method in which the imprint material 31a is ejected in droplets. Alternatively, a known spin coating method can be used as a conventional resist coating method.

  As described above, in the present invention, the surface of the covering filler layer 21 including the step 22 shown in FIG. 3A is formed by applying the nanoimprint lithography technique to form the planarization layer 31. Even if it has unevenness, the surface unevenness can be absorbed by the planarizing layer 31 to form a flatter surface.

In the present invention, various materials used for nanoimprint lithography can be used as the imprint material 31a. The planarized layer 31 obtained by curing the imprint material 31a forms the work surface 2 as described above. In the step of performing, the ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction of the covering filler layer 21 to the etching rate (Ep) in the thickness direction of the planarization layer 31 is
Ec / Ep ≦ 1
It is preferable that the relationship is satisfied.
This is because the surface of the covering filler layer 21 can be flattened by repeating the above-described flattening layer forming step and the etching step of eliminating the flattening layer 31. The details of this relationship will be described in the process surface forming step described later.

In the present invention, the ratio of the etching rate (Ec) in the thickness direction of the covering filler layer 21 to the etching rate (Ep) in the thickness direction of the planarizing layer 31 in the step of forming the workpiece surface 2 ( Ec / Ep)
0.9 ≦ Ec / Ep ≦ 1.1
It may satisfy the relationship.
If the material constituting the planarization layer 31 satisfies the above-described relationship, a processed surface having a generally desired flatness can be obtained in a single process without performing the above-described repeating process. Because you can.

  Specific examples of the imprint material 31a include an ultraviolet curable resin and a thermoplastic resin.

In the present invention, various members having a flat surface satisfying a desired flatness can be used as the flattening member 40. For example, a synthetic quartz glass substrate used for manufacturing a photomask or a template for nanoimprinting can be used. A synthetic quartz glass substrate used for production can be suitably used.
In particular, if it is a synthetic quartz glass substrate used in the manufacture of a template for nanoimprint, it has essentially the same flatness as the level required for the processed surface of the template substrate regenerated by the present invention. preferable. Moreover, it is preferable also in the point which has ultraviolet-ray transmittance.

(Work surface forming process)
Next, the process for forming the work surface will be described.
As shown in FIG. 1D, in the method for manufacturing a template substrate according to the present invention, etching is performed in the thickness direction until the planarizing layer 31 and the covering filler layer 21 disappear, and the processed surface 2 A template substrate 1 having the following is manufactured.
Here, in the present invention, as described above, the coating filler layer 21 with respect to the etching rate (Ep) in the thickness direction (Z direction shown in FIG. 1) of the planarization layer 31 formed on the coating filler layer 21. The ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction of
Ec / Ep ≦ 1
Satisfy the relationship
The ratio (Eb / Ec) of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the coating filler layer 21 is
Eb / Ec ≦ 1
It is preferable to satisfy the relationship.
By repeating a series of the above-described covering filler layer forming step, planarizing layer forming step, etching step for eliminating the flattening layer 31, and etching step for eliminating the covering filler layer 21, a flat workpiece is processed. This is because the template substrate 1 having the surface 2 can be obtained.

  The process surface forming process according to the present invention will be described in more detail with reference to FIGS. Here, FIG. 4 is an explanatory view showing a process in which the surface of the covering filler layer 21 is flattened by the etching according to the present invention, and FIG. 5 shows a flat work surface 2 by the etching according to the present invention. It is explanatory drawing which shows the process formed.

First, the process in which the surface of the coating filler layer 21 is planarized by etching according to the present invention will be described.
For example, as in the example shown in FIG. 4, in the dry etching using the etching gas 61, the etching rate in the thickness direction (Z direction shown in FIG. 4) of the planarization layer 31 formed on the coating filler layer 21. The ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction of the coating filler layer 21 to Ep) is
Ec / Ep = 1
If the above relationship is satisfied, the covering filler layer 21 has surface irregularities such as the step 22 as shown in FIG. 3A, and is flat as shown in FIG. Even if the etching of the planarizing layer 31 proceeds, the planarizing layer 31 partially remains and the surface of the covering filler layer 21 is partially exposed, the etching rate in the thickness direction of the remaining planarizing layer 31 ( Ep) and the etching rate (Ec) in the thickness direction of the exposed coating filler layer 21 are equal, and thereafter, the same thickness amount disappears in both the planarization layer 31 and the coating filler layer 21. After all the flattening layer 31 has disappeared, the covering filler layer 21 having a flattened surface remains (FIG. 4D).

Next, a process in which the flat work surface 2 is formed by etching according to the present invention will be described.
As in the example shown in FIG. 5, for example, in the dry etching using the etching gas 62, the pattern forming surface 11 of the template 10 is configured with respect to the etching rate (Ec) in the thickness direction of the material forming the coating filler layer 21. The ratio (Eb / Ec) of the etching rate (Eb) of the material is
Eb / Ec = 1
When the relationship is satisfied, as shown in FIG. 5B, the coating filler layer 21 is etched, the coating filler layer 21 partially remains, and the surface of the template 10 is partially exposed. Since the etching rate (Ec) in the thickness direction of the remaining coating filler layer 21 and the etching rate (Eb) in the thickness direction of the exposed template 10 are equal, the coating filler layer 21, After both of the templates 10 have lost the same thickness, and all of the covering filler layer 21 has disappeared, the template substrate 1 having the flat work surface 2 can be obtained (FIG. 5C).

Here, in the example shown in FIG. 4 and FIG. 5, the etching in the thickness direction of the covering filler layer 21 with respect to the etching rate (Ep) in the thickness direction of the planarizing layer 31 formed on the covering filler layer 21 is performed. The ratio of speed (Ec) (Ec / Ep) is
Ec / Ep = 1
The ratio (Eb / Ec) of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the coating filler layer 21 is satisfied.
Eb / Ec = 1
However, in the present invention, as described above, the coating filler layer 21 has an etching rate (Ep) in the thickness direction of the planarization layer 31 formed on the coating filler layer 21. The ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction is
Ec / Ep ≦ 1
Satisfy the relationship
The ratio (Eb / Ec) of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the coating filler layer 21 is
Eb / Ec ≦ 1
Even etching that satisfies the above relationship can be suitably used.

  In this case, for example, the step of etching in the thickness direction until the planarization layer 31 disappears is the first etching step, and the step of etching in the thickness direction until the covering filler layer 21 disappears. As the second etching step, the surface of the covering filler layer 21 can be flattened by repeating the above-described flattening layer forming step (S3) and the first etching step (S4). By repeating a series of steps of the covering filler layer forming step (S2), the flattening layer forming step (S3), the first etching step (S4), and the second etching step (S5), a flat work surface A template substrate 1 having 2 can be obtained.

  However, from the viewpoint of manufacturing cost, in the first etching step (S4), the covering filler with respect to the etching rate (Ep) in the thickness direction of the planarization layer 31 formed on the covering filler layer 21 is as much as possible. It is preferable to set the conditions so that the ratio (Ec / Ep) of the etching rate (Ec) in the thickness direction of the layer 21 is 1. In the second etching step (S5), as much as possible, the coating filling The ratio of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the material layer 21 is 1 (Eb / Ec). It is preferable to set conditions. In particular, it is preferable that the value of Eb / Ec is close to 1 in the second etching step (S5). This is because the number of repeated steps can be reduced.

In the present invention, the ratio of the etching rate (Ec) in the thickness direction of the coating filler layer 21 to the etching rate (Ep) in the thickness direction of the planarization layer 31 formed on the coating filler layer 21 (Ec / Ep)
0.9 ≦ Ec / Ep ≦ 1.1
The ratio (Eb / Ec) of the etching rate (Eb) of the material constituting the pattern forming surface 11 of the template 10 to the etching rate (Ec) in the thickness direction of the material constituting the coating filler layer 21 is satisfied.
0.9 ≦ Eb / Ec ≦ 1.1
It may satisfy the relationship.
If the material constituting the covering filler layer 21 satisfies the above-described relationship, a processed surface having a generally desired flatness can be obtained in one step without performing the above-described repetitive steps. Because it can.

In the present invention, for example, synthetic quartz glass is used as a material constituting the template 10, an acrylic ultraviolet curable resin is used as a material constituting the planarization layer 31, and an etching gas in the first etching step is used. the use of a fluorine-based gas such as CF _4, the material constituting the coating filler layer 21 using a silicon oxide, the etching gas in the second etching step may be used a fluorine-based gas such as CF _4.

  In the template substrate manufacturing method according to the present invention, the first etching step (S4) and the second etching step (S5) may be performed under different conditions or under the same conditions. Etching may be used. Further, the conditions may be changed in a plurality of stages or continuously from the initial stage of the first etching step (S4) to the end stage of the second etching step (S5). .

In the method for manufacturing a template substrate according to the present invention, the uneven transfer pattern 12 may be completely removed by the etching described above, but the recess 12A having a depth of several tens of nanometers has a depth of about several nanometers. The template substrate 1 having a flat work surface 2 is regenerated by reducing the height (depth) of the transfer pattern 12 by etching until it is finished, and then performing a secondary polishing process in the conventional polishing process. May be.
If the depth of the recess 12A is reduced to about several nanometers by the etching described above, it is possible to prevent the occurrence of cracks and chips even if the above-described secondary polishing treatment is used. In addition, it is possible to suppress the region near the end of the top surface of the mesa-shaped convex structure from being polished more than the central region of the top surface.

  The secondary polishing treatment as described above is not particularly limited as long as it is a method capable of polishing the upper surface of the mesa-shaped convex structure without causing cracks or chips in the nanoimprint template 10 to be reproduced. For example, chemical mechanical polishing (CMP) using a colloidal silica containing silica particles having an average particle diameter of about several tens to several hundreds of nanometers as a polishing slurry can be used.

<Method for producing template for nanoimprint>
Next, a method for producing a nanoimprint template according to the present invention will be described with reference to the drawings.
The nanoimprint template manufacturing method according to the present invention forms a new transfer pattern on the processed surface of the template substrate manufactured by the above-described template substrate manufacturing method according to the present invention.
According to the method for producing a nanoimprint template of the present invention, the production cost of the nanoimprint template can be kept low by using the regenerated template substrate.
The new transfer pattern to be formed does not have to be the same as the transfer pattern formed on the template before regenerating the template substrate, and a desired transfer pattern can be formed.

For the formation of this new transfer pattern, a method conventionally used as a method for forming the transfer pattern of the nanoimprint template can be applied.
For example, as shown in FIG. 7A, first, a hard mask layer 71A is formed on the processed surface of the template substrate 1 manufactured by the template substrate manufacturing method according to the present invention described above.
Next, an electron beam resist is applied on the hard mask layer 71A, electron beam drawing, development, and rinsing are performed to form a resin pattern 72 (FIG. 7B). In the present invention, the method of forming the resin pattern 72 is not limited to the above method, and for example, the resin pattern 72 may be formed using a known nanoimprint technique.

Next, the hard mask layer 71A exposed from the resin pattern 72 is etched to form the hard mask pattern 71 (FIG. 7C).
Thereafter, the resin pattern 72 is removed, and then the processed surface of the template substrate 1 exposed from the hard mask pattern 71 is etched to form a new transfer pattern 82 (FIG. 7D). By removing the mask pattern 71, a nanoimprint template 80 having a new transfer pattern 82 on the pattern formation surface 81 (corresponding to the processing surface 2 of the template substrate 1) can be obtained (FIG. 7E).

The hard mask layer 71A can be used as long as it has resistance to etching when the template substrate 1 is etched to form a new transfer pattern 82, such as chromium (Cr). A thin film formed by sputtering a metal can be preferably used. Although the film thickness depends on the size of the transfer pattern 82 to be formed, it can be, for example, about 3 nm to 10 nm.
When chromium (Cr) is used as the material constituting the hard mask layer 71A, the hard mask pattern 71 can be formed by dry etching using a mixed gas of chlorine and oxygen. Further, the transfer pattern 82 can be formed by dry etching using a fluorine-based gas such as CF ₄ by using the hard mask pattern 71 as an etching mask.

  As mentioned above, although the manufacturing method of the template board | substrate concerning this invention and the manufacturing method of the template for nanoimprints concerning this invention were demonstrated, this invention is not limited to the said embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the case. It is included in the technical scope of the invention.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
<Template substrate manufacturing method>
(Template preparation process)
As a template 10 before reproduction, on the first side of a synthetic quartz glass substrate having a plane size of 6 inches square and a thickness of 0.25 inches, it has a mesa-like convex structure having a pattern forming surface 11 as a main surface, On the second side, a template having a concave structure including the convex structure in plan view was prepared.
Here, the height of the mesa-shaped convex structure is 30 μm, the size of the main surface is 26 mm × 33 mm, and the planar center of the mesa-shaped convex structure coincides with the planar center on the first side of the template. The one arranged so as to be used.
In addition, the concave structure described above has a circular opening having a diameter of 64 mm on the second side and a depth of 5 mm, so that the planar center of the concave structure coincides with the planar center on the first side of the template. What was arrange | positioned in was used.
Further, on the main surface of the above mesa-shaped convex structure, a concavo-convex line-and-space pattern having a concave portion 12A depth of 60 nm, a concave portion 12A width of 30 nm, and a convex portion 12B width of 30 nm as a transfer pattern 12. What was formed was used.

(Coating filler layer formation process)
Next, the template is mounted on an atomic layer deposition apparatus, and a source gas containing silicon (tri-dimethylaminosilane gas) and a reaction gas containing oxygen (mixed gas of O ₂ gas and H ₂ O gas) are alternately used. A silicon oxide film having a thickness of 20 nm was formed as the coating filler layer 21 on the pattern formation surface 11 by using the atomic layer deposition method to be supplied.
Here, since the silicon oxide film is formed by using an atomic layer deposition method, the pattern formation surface 11 is covered with high shape followability and the transfer pattern 12 is filled. The thickness (20 nm) of the formed silicon oxide film is not less than 1/2 of the opening size of the recess 12A of the transfer pattern 12 (that is, the width of the recess 12A, 30 nm). The twelve recesses 12A can be reliably filled.

(Planarization layer forming process)
Next, the template on which the silicon oxide film is formed is mounted on a nanoimprint apparatus, and a radical polymerization type acrylic ultraviolet curable resin is used as an imprint material 31a on the silicon oxide film by an inkjet method. Supplied.
Subsequently, as the planarizing member 40, a synthetic quartz glass substrate used in the manufacture of a template for nanoimprinting is used. The flat surface of the synthetic quartz glass substrate is brought into contact with the acrylic ultraviolet curable resin, and The acrylic ultraviolet curable resin was formed into a layered form having a flat upper surface.
Next, the acrylic ultraviolet curable resin is cured by transmitting the synthetic quartz glass substrate and irradiating ultraviolet rays, and then the synthetic quartz glass substrate is released from the silicon oxide. A template in which an acrylic resin having a film thickness of 20 nm was formed on the film as the planarizing layer 31 was obtained.

(Work surface forming process)
Next, the template on which the acrylic resin is formed is mounted on an inductively coupled plasma (ICP) type dry etching apparatus. First, the planarization layer 31 made of the acrylic resin is provided. Etching in the thickness direction until it disappears, and then etching in the thickness direction until the coating filler layer 21 composed of the silicon oxide film disappears, and all of the uneven transfer pattern 12 disappears, A template substrate 1 having a flat work surface 2 was obtained.
Here, both the etching for eliminating the planarizing layer 31 composed of the acrylic resin and the etching for eliminating the covering filler layer 21 composed of the silicon oxide film include etching gas. CF ₄ gas was used.

  The ratio of the etching rate in the thickness direction of the coating filler layer 21 to the etching rate in the thickness direction of the planarizing layer 31 is 0.98, and the ratio of the etching rate in the thickness direction of the coating filler layer 21 is The ratio of the etching rate in the thickness direction of the synthetic quartz glass constituting the pattern forming surface of the template was 0.97.

<Method for producing template for nanoimprint>
Next, the template substrate 1 obtained as described above was mounted on a sputter deposition apparatus, and a chromium thin film having a thickness of 5 nm was formed on the processed surface of the template substrate 1 as a hard mask layer 71A.
Next, an electron beam resist was applied on the chromium thin film, and electron beam drawing, development and rinsing were performed to form a 1: 1 line and space pattern resin pattern having a line width of 30 nm.
Next, the chromium thin film exposed from the above resin pattern was dry-etched using a mixed gas of chlorine and oxygen to form a chromium thin film pattern, and then the resin pattern was removed by ashing treatment using oxygen plasma.
Next, dry etching using CF ₄ gas is performed on the work surface of the template substrate 1 exposed from the chromium thin film pattern, and then the chromium thin film pattern is removed by dry etching using a mixed gas of chlorine and oxygen. Then, a template 80 having a concave and convex line-and-space pattern in which the depth of the concave portion 82A is 60 nm, the width of the concave portion 82A is 30 nm, and the width of the convex portion 82B is 30 nm as a new transfer pattern 82 on the pattern forming surface 81. Got.

DESCRIPTION OF SYMBOLS 1 ... Template substrate 2 ... Processed surface 10, 80 ... Nanoimprint template 11, 81 ... Pattern formation surface 12, 82 ... Transfer pattern 12A, 82A ... Concave part 12B, 82B ..Protrusions 21 ... covering filler layer 22 ... step 31 ... flattening layer 31a ... imprint material 40 ... flattening member 50 ... ultraviolet rays 61, 62 ... etching Gas 71 ... Hard mask pattern 71A ... Hard mask layer 72 ... Resin pattern 110, 210, 211 ... Nanoimprint template 110a ... First side 110b ... Second side 111 ..Pattern forming surface 112 ... Transfer pattern 113 ... Convex structure 114 ... Concave structure

Claims (7)

A method for producing a template substrate having a flat work surface from a nanoimprint template having a pattern-formed surface on which an uneven transfer pattern is formed,
A preparation step of preparing the nanoimprint template;
A covering filler layer forming step of forming a covering filler layer on the pattern forming surface so as to cover the pattern forming surface and be filled in the transfer pattern;
A planarization layer forming step of forming a planarization layer on the coating filler layer by supplying an imprint material on the coating filler layer and bringing a planarizing member having a planar surface into contact with the imprint material. When,
A processed surface forming step of forming the processed surface by etching in the thickness direction until the planarizing layer and the covering filler layer disappear,
In order ,
In the process surface forming step,
The ratio of the etching rate in the thickness direction of the covering filler layer to the etching rate in the thickness direction of the planarization layer is a value of 1 or less,
Etching is performed under the condition that the ratio of the etching rate in the thickness direction of the material constituting the pattern forming surface of the template to the etching rate in the thickness direction of the covering filler layer is a value of 1 or less. A method for manufacturing a substrate. A method for producing a template substrate having a flat work surface from a nanoimprint template having a pattern-formed surface on which an uneven transfer pattern is formed,
A preparation step of preparing the nanoimprint template;
A covering filler layer forming step of forming a covering filler layer on the pattern forming surface so as to cover the pattern forming surface and be filled in the transfer pattern;
A planarization layer forming step of forming a planarization layer on the coating filler layer by supplying an imprint material on the coating filler layer and bringing a planarizing member having a planar surface into contact with the imprint material. When,
A processed surface forming step of forming the processed surface by etching in the thickness direction until the planarizing layer and the covering filler layer disappear,
In order,
In the process surface forming step,
The ratio of the etching rate in the thickness direction of the covering filler layer to the etching rate in the thickness direction of the planarization layer is a value of 0.9 or more and 1.1 or less,
Etching is performed under the condition that the ratio of the etching rate in the thickness direction of the material constituting the pattern forming surface of the template to the etching rate in the thickness direction of the covering filler layer is 0.9 or more and 1.1 or less. A method for manufacturing a template substrate, comprising: The workpiece surface forming step includes
A first etching step of etching in the thickness direction until the planarizing layer disappears;
The method for manufacturing a template substrate according to claim 1, further comprising a second etching step in which etching is performed in a thickness direction until the covering filler layer disappears . The covering filler layer forming step is a film forming step using an atomic layer deposition method,
The thickness of the said covering filler layer formed by the said atomic layer deposition method is a magnitude | size of 1/2 or more of the opening dimension of the recessed part of the said transfer pattern, The any one of Claims 1-3 characterized by the above-mentioned. The manufacturing method of the template board | substrate as described in a term. The nanoimprint template has a first side on which the transfer pattern is provided, and a second side facing the first side,
The method for manufacturing a template substrate according to claim 1 , wherein a convex structure having the pattern forming surface as a main surface is formed on the first side . The nanoimprint template has a first side on which the transfer pattern is provided, and a second side facing the first side,
The method for manufacturing a template substrate according to claim 1, wherein a concave structure is formed on the second side . A method for producing a template for nanoimprinting, wherein a new transfer pattern is formed on a work surface of a template substrate produced by the method for producing a template substrate according to any one of claims 1 to 6 .

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