JP2016146507A - Method for manufacturing template for nano-imprint lithography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a template for nano-imprint lithography capable of precisely forming a desired reversion pattern by preventing deformation of a resist pattern.SOLUTION: A hard mask layer is provided on a principal plane of a substrate serving as a template for nano-imprint lithography, and a resist pattern is formed on the hard mask layer. At least a coating film in a lowermost layer is formed at temperature lower than glass transition temperature of resin constituting the resist pattern using an atomic layer deposition method, and thereafter, the coating film on an upper face of the resist pattern is removed to expose the resist pattern. The hard mask layer exposed after removing the resist pattern is etched to form a hard mask pattern, and the hard mask pattern is used for an etching mask to etch the substrate, thereby forming a desired transfer pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a template used in nanoimprint lithography in which a fine uneven transfer pattern is transferred to a resin formed on a transfer substrate.

In semiconductor device manufacturing, photolithography technology using a photomask has been used in the past, and in recent years, as a technology for further improving the resolution, photolithography using a phase shift mask has been used to make fine devices such as VLSI. The pattern is manufactured.
However, in order to cope with further miniaturization, the limitations of the above-described photolithography method have been pointed out due to the problem of exposure wavelength and the problem of manufacturing cost, and EUV using a reflective mask as the next generation lithography technology. (Extreme Ultra Violet) lithography and nanoimprint lithography (NIL) using a template have been proposed.
In particular, nanoimprint lithography is attracting attention because it is economically advantageous because it does not use an expensive exposure apparatus (stepper) such as photolithography.

  In the nanoimprint lithography described above, a template (also referred to as a mold, a stamper, or a mold) on which a fine concavo-convex shape transfer pattern is formed is closely attached to a resin formed on a substrate to be transferred such as a semiconductor wafer, The shape of the surface side of the resin is molded into the concavo-convex shape of the transfer pattern of the template, and then the template is released, and then the excess resin portion (residual film portion) is removed by dry etching or the like. This is a technique for transferring the concave / convex shape (more specifically, the concave / convex inverted shape) of the template transfer pattern to a resin on the transfer substrate (for example, Patent Documents 1 and 2).

In order to form a desired resin pattern using the nanoimprint lithography technique, for example, as shown in FIG. 6A, first, a nanoimprint lithography template 100 having a concavo-convex shaped transfer pattern, and an ultraviolet curable A substrate to be transferred 211 provided with a resin 212 is prepared. Next, the template 100 is brought into close contact with the resin 212 provided on the substrate to be transferred 211 and irradiated with ultraviolet rays 230 to cure the resin 212 (FIG. 6 ( b)) After that, the template 100 is released (FIG. 6C).
Next, the cured resin pattern 212a on the transfer substrate 211, for example, by performing dry etching by reactive ion 240 such as oxygen ions, to remove excess residual film portion of the thickness T _R (FIG. 6 (D)), a desired resin pattern 212b having a concavo-convex shape inverted from the transfer pattern of the template 100 is obtained (FIG. 6E).
Here, the thickness T _R of the residual film portion of the above, in nanoimprint lithography, and is called a RLT (Residual Layer Thickness).

In order to manufacture the template used for the nanoimprint lithography as described above, for example, as shown in FIG. 7A, first, a substrate 111 provided with a hard mask layer 112 on a main surface is prepared, and a substrate 111 is formed thereon. An electron beam resist is applied, and exposure, development, and the like are performed using an electron beam (EB) lithography technique to form a resist pattern 113 (FIG. 7B).
Next, the hard mask layer 112 exposed from the resist pattern 113 is etched to form a hard mask pattern 112a (FIG. 7C), and then the resist pattern 113 is removed (FIG. 7D). ).
Next, the substrate 111 exposed from the hard mask pattern 112a is etched (FIG. 7E), and then the hard mask pattern 112a is removed to form a nanoimprint lithography template 100 having a transfer pattern 120 having a desired uneven shape. Is obtained (FIG. 7 (f)).

Moreover, the template for nanoimprint lithography can also be manufactured using the technique of the above-mentioned nanoimprint lithography (for example, patent document 3).
That is, if the transferred substrate 211 in FIG. 6 is replaced with a template substrate in which a hard mask layer is provided on the main surface, after the process shown in FIG. By performing the process shown in f), a replica template (replica template) having a transfer pattern with the concavo-convex shape inverted can be manufactured from the parent template (master template).

JP-T-2004-504718 JP 2002-93748 A JP 2006-91089 A JP 2008-290316 A

As described above, in nanoimprint lithography, the resin pattern formed on the substrate to be transferred is a pattern whose concavo-convex shape is inverted from the transfer pattern of the template for nanoimprint lithography (see, for example, FIG. 6).
For example, when it is desired to form a hole pattern (concave hole pattern) on the substrate to be transferred, the transfer pattern of the template for nanoimprint lithography is a pillar pattern (convex columnar pattern).

When the pillar pattern (convex columnar pattern) as described above is formed as a transfer pattern of a template for nanoimprint lithography, the electron beam resist used for manufacturing the template for nanoimprint lithography may be a negative type. preferable.
If a negative type electron beam resist is used, it is only necessary to irradiate only the pillar pattern portion with an electron beam. Usually, the area ratio of the total area of the pillar pattern to the entire substrate is 50% or less. This is because the writing time can be shortened compared to the case of using a type of electron beam resist.

  However, at present, electron beam resists that satisfy the requirements of resolution and sensitivity that can be used in the manufacture of a template for nanoimprint lithography exist in the positive type, but the negative type has no practical resistance.

  Here, as a method for inverting the pattern while using a positive resist pattern, a method of spin coating an SOG (Spin On Glass) material on the resist pattern, a CVD (Chemical Vapor Deposition) method, a vapor deposition method, or the like. A method of forming an inversion pattern by the inversion layer by forming an inversion layer by removing the inversion layer until the surface of the resist pattern is exposed, and then removing the resist pattern is proposed. (Patent Document 4).

However, when the SOG or CVD method is used to form the inversion layer, since a high temperature is usually required, the resist pattern is deformed by heat, and a desired inversion pattern cannot be accurately formed. .
For example, the glass transition temperature of a resin constituting a general positive electron beam resist is about 100 ° C. to 150 ° C., whereas the heat treatment temperature when using SOG is about 400 ° C. When using this method, it is usually necessary to heat the substrate at 200 ° C. or higher.

On the other hand, when a vapor deposition method or a sputtering method is used to form the inversion layer, there is a problem in shape followability (also called step coverage or step coverage).
For example, in a film formation method using a vapor deposition method or a sputtering method, when there is a step such as an uneven shape in a film formation target, a film is likely to be formed at a corner of a flat portion or a protrusion, whereas a corner of a recess Tends to be difficult to form a film.
That is, in the film-forming method such as the vapor deposition method or the sputtering method, for example, when the resist pattern is a hole pattern with a high aspect ratio, it is difficult to form a film on the bottom portion (particularly, the end portion of the bottom portion). A film is formed only at the corners of the upper surface.
Therefore, when the evaporation method or the sputtering method is used to form the inversion layer, it is not possible to form an inversion layer that faithfully follows the shape of the resist pattern. It cannot be formed.

  The present invention has been made in view of the above circumstances, and in forming a transfer pattern of a template for nanoimprint lithography, the drawing time can be reduced, the resist pattern can be prevented from being deformed, and a desired inversion pattern can be accurately formed. An object of the present invention is to provide a method for producing a template for nanoimprint lithography.

  As a result of various studies, the present inventor has provided a hard mask layer on the main surface of a substrate to be a template for nanoimprint lithography, formed a resist pattern thereon, and formed at least a lowermost coating film with an atomic layer deposition method. Is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern, and then the resist film is exposed by removing the coating film on the upper surface of the resist pattern, and then exposed after removing the resist pattern. The present invention finds that the above problem can be solved by etching a hard mask layer to form a hard mask pattern and etching the substrate using this hard mask pattern as an etching mask to form a desired transfer pattern. Is completed.

  That is, the invention according to claim 1 of the present invention is a method for manufacturing a template for nanoimprint lithography having a concavo-convex shaped transfer pattern on a main surface of a substrate, comprising: a hard mask layer provided on the main surface of the substrate; On top of the resist pattern, and using the atomic layer deposition method at a temperature lower than the glass transition temperature of the resin constituting the resist pattern, and from the resist pattern Forming a coating film covering the upper surface of the exposed hard mask layer, and leaving the coating film covering the upper surface of the hard mask layer by dry etching, while leaving the coating film on the upper surface of the resist pattern; Removing and exposing the resist pattern; removing the exposed resist pattern; Etching the hard mask layer at a portion exposed by removing the dyst pattern to form a hard mask pattern, and etching the substrate exposed from the hard mask pattern to form the concavo-convex shaped transfer pattern And a step of removing the hard mask pattern in order, and in the step of forming the coating film, the thickness of the coating film formed on the upper surface of the resist pattern is set to the bottom side of the resist pattern. It is a manufacturing method of the template for nanoimprint lithography characterized by setting it as 1/2 or more of an opening size.

  In the invention according to claim 2 of the present invention, the step of forming the coating film alternately supplies a gas containing silicon and a gas containing one or more of oxygen, nitrogen, and fluorine. It is a manufacturing method of the template for nanoimprints of Claim 1 characterized by including the process to do.

  The invention according to claim 3 of the present invention is a method for manufacturing a template for nanoimprint lithography having a concavo-convex shaped transfer pattern on a main surface of a substrate, comprising: a hard mask layer provided on the main surface of the substrate; On top of the resist pattern, and using the atomic layer deposition method at a temperature lower than the glass transition temperature of the resin constituting the resist pattern, and from the resist pattern Forming a first coating film covering an upper surface of the exposed hard mask layer; forming a second coating film on the first coating film; and The first coating film and the second coating film on the upper surface of the resist pattern while leaving at least a part of the first coating film and the second coating film on the upper surface. And exposing the resist pattern, removing the exposed resist pattern, and etching the hard mask layer exposed by removing the resist pattern to form a hard mask pattern. Forming the second coating film by sequentially including a step, a step of etching the substrate exposed from the hard mask pattern to form the uneven transfer pattern, and a step of removing the hard mask pattern The step of forming is a film forming step using an atomic layer deposition method, and is a step of forming the second coating film at a temperature different from that of the first coating film. It is a manufacturing method of the template for use.

  The invention according to claim 4 of the present invention is a method for manufacturing a template for nanoimprint lithography having a concavo-convex shaped transfer pattern on a main surface of a substrate, comprising: a hard mask layer provided on the main surface of the substrate; On top of the resist pattern, and using the atomic layer deposition method at a temperature lower than the glass transition temperature of the resin constituting the resist pattern, and from the resist pattern Forming a first coating film covering an upper surface of the exposed hard mask layer; forming a second coating film on the first coating film; and The first coating film and the second coating film on the upper surface of the resist pattern while leaving at least a part of the first coating film and the second coating film on the upper surface. And exposing the resist pattern, removing the exposed resist pattern, and etching the hard mask layer exposed by removing the resist pattern to form a hard mask pattern. Forming the second coating film by sequentially including a step, a step of etching the substrate exposed from the hard mask pattern to form the uneven transfer pattern, and a step of removing the hard mask pattern The step of forming is a film forming step using an atomic layer deposition method, and is a step of forming the second coating film using a gas containing an element different from the first coating film. It is the manufacturing method of the template for the nanoimprint lithography characterized.

  In the invention according to claim 5 of the present invention, the step of forming the first coating film includes a gas containing silicon and a gas containing any one or more of oxygen, nitrogen, and fluorine. The method for producing a template for nanoimprint lithography according to claim 3, further comprising a step of alternately supplying.

  The invention according to claim 6 of the present invention is the method for producing a template for nanoimprint lithography according to claim 3, wherein the second coating film is made of a material containing silicon. is there.

According to the present invention, at least the lowermost coating film is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern using an atomic layer deposition method, and the resist pattern is formed using this coating film. Since it is possible to form a pattern in which the unevenness is reversed, it is possible to obtain a reversal pattern having a high shape following property even for a shape having a high aspect ratio while preventing deformation of the resist pattern in the formation of the transfer pattern. .
In addition, since a reverse pattern of the resist pattern can be obtained, the resist drawing time is shortened while using a positive resist even for a transfer pattern suitable for a negative resist like the above-mentioned pillar pattern. can do.
Therefore, according to the method for manufacturing a template for nanoimprint lithography according to the present invention, nanoimprint lithography having a transfer pattern accurately formed in a desired shape while achieving a reduction in manufacturing cost associated with shortening a drawing time. Templates can be manufactured.

It is a schematic process drawing which shows an example of the manufacturing method of the template for nanoimprint lithography concerning this invention. It is a schematic process drawing which shows an example of the manufacturing method of the template for nanoimprint lithography concerning this invention following FIG. It is explanatory drawing about an example of the coating film formed using the atomic layer deposition method. It is a schematic process drawing which shows the other example of the manufacturing method of the template for nanoimprint lithography which concerns on this invention. It is a schematic process drawing which shows the other example of the manufacturing method of the template for nanoimprint lithography which concerns on this invention following FIG. It is a schematic process drawing which shows an example of the conventional nanoimprint lithography. It is a schematic process drawing which shows an example of the manufacturing method of the conventional template for nanoimprint lithography.

  Hereinafter, a method for manufacturing a template for nanoimprint lithography according to the present invention will be described with reference to the drawings.

(First embodiment)
First, a first embodiment of a method for manufacturing a template for nanoimprint lithography according to the present invention will be described with reference to FIGS.
Here, FIG. 1 is a schematic process diagram showing an example of the first half of the method for manufacturing a template for nanoimprint lithography according to the present embodiment (the first embodiment) of the present invention, and FIG. It is a schematic process drawing which shows an example of the subsequent process.

  A method for manufacturing a template for nanoimprint lithography according to the present embodiment (first embodiment) of the present invention is a method for manufacturing a template for nanoimprint lithography having a concavo-convex shaped transfer pattern on the main surface of the substrate, The resist pattern is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern by using a step of forming a resist pattern on the hard mask layer provided on the main surface and an atomic layer deposition method. Forming a coating film covering the upper surface and side surfaces of the hard mask layer and the upper surface of the hard mask layer exposed from the resist pattern; and leaving the coating film covering the upper surface of the hard mask layer, Removing the coating film on the upper surface to expose the resist pattern; and Forming a hard mask pattern by etching a portion of the hard mask layer exposed by removing the resist pattern, and etching the substrate exposed from the hard mask pattern. A step of forming the uneven transfer pattern and a step of removing the hard mask pattern are sequentially provided.

  For example, in order to obtain the nanoimprint lithography template 10 by the manufacturing method of the present embodiment, first, as shown in FIG. 1A, a substrate 11 having a hard mask layer 12 provided on the main surface is prepared.

  The substrate 11 can be used as long as it can be applied to a template for nanoimprint lithography. However, the substrate 11 has high surface flatness to obtain transfer accuracy, and excellent resistance to a cleaning liquid used for cleaning in the template manufacturing process. A synthetic quartz glass substrate or the like is generally used.

As the material of the hard mask layer 12, any material can be used as long as the etching selectivity with the substrate 11 is sufficient. For example, chromium (Cr), molybdenum (Mo), titanium (Ti), tantalum (Ta) ), A metal such as aluminum (Al), an oxide such as the metal, a nitride, or the like can be used.
The hard mask layer 12 may be a multilayer film of two or more layers made of different materials.

Among the materials described above, a chromium-based material is a preferable material because it has a strong resistance to a fluorine-based gas plasma used for dry etching of a quartz glass substrate and is easily wet-etched.
For example, when a synthetic quartz glass substrate is used as the substrate 11, a chromium (Cr) sputtering film can be used as the hard mask layer 12, and the film thickness depends on the size of the transfer pattern to be formed. The range may be about several nm to 10 nm.

Next, as shown in FIG. 1B, a resist pattern 13 is formed on the hard mask layer 12. Here, as the resist constituting the resist pattern 13, various resists used for a photomask or the like can be used.
However, in nanoimprint lithography, in order to cope with further miniaturization as compared with photolithography using a conventional photomask, it is necessary to use an electron beam resist having a high resolution as a resist related to the transfer pattern of the template 10. From the viewpoint of manufacturing cost, it is necessary to use a resist having a certain degree of sensitivity in order to suppress an increase in writing time.
In the present invention, for example, a positive electron beam resist ZEP520A manufactured by Nippon Zeon can be used as a resist that satisfies the above requirements.

  Next, as shown in FIGS. 1C and 1D, the upper surface of the resist pattern 13 is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern 13 by using an atomic layer deposition method. And a side surface and a coating film 14 covering the upper surface of the hard mask layer 12 exposed from the resist pattern 13, and then covering the upper surface of the hard mask layer 12 as shown in FIG. The coating film 14 on the upper surface of the resist pattern 13 is removed, leaving the resist pattern 13 exposed.

As a method of removing the coating film 14 on the upper surface of the resist pattern 13 described above, dry etching using an etching gas capable of removing the material constituting the coating film 14 can be used.
For example, if the material constituting the coating film 14 includes silicon (Si), a fluorine-based gas (CF ₄ , CHF ₃ , C ₂ F _6, etc.) or a mixed gas thereof is used as an etching gas. be able to.

  Here, the atomic layer deposition method (ALD method: Atomic Layer Deposition method) uses two kinds of gases, a source gas containing metal or silicon, and a reactive gas containing oxygen, fluorine, or the like, alternately on the substrate. This is a technology for forming a thin film in units of layers. This process consists of four steps: supplying gas containing metal or silicon, removing excess gas, supplying gas containing oxygen, etc., and removing excess gas. This is a film formation technique for repeatedly forming a film having a desired thickness.

For example, when forming a SiO ₂ film on a substrate, a source gas containing silicon and a reaction gas containing oxygen are used alternately. Similarly, a SiN film can be formed on a substrate using a source gas containing silicon and a reaction gas containing nitrogen.
Further, a gas containing a plurality of elements may be used as the reaction gas. For example, a SiON film is formed on the substrate using a source gas containing silicon and a reaction gas containing oxygen and nitrogen, or a substrate using a source gas containing silicon and a reaction gas containing oxygen and fluorine, A SiOF film can also be formed thereon.

  As described above, since the atomic layer deposition method can form a thin film in units of atomic layers, it has a high shape following property, and has a lower temperature than a general CVD (Chemical Vapor Deposition) method. It is also possible to form a film at (for example, room temperature).

Therefore, if the above-described atomic layer deposition method is used for forming the coating film 14 as in the present invention, the temperature lower than the glass transition temperature of the resin constituting the resist pattern 13 while satisfying high shape followability. Thus, the coating film 14 can be formed.
For example, in the present invention, when the above-mentioned positive electron beam resist ZEP520A manufactured by ZEON Corporation is used as the resist for forming the resist pattern 13, the glass transition temperature is 105 ° C. What is necessary is just to form the coating film 14 below (for example, the range of about 20-100 degreeC). This is because the resist pattern can be prevented from being deformed by heat within such a temperature range.

  If the above-described atomic layer deposition method is used to form the coating film 14 as in the present invention, the upper and side surfaces of the resist pattern 13 and the hard pattern exposed from the resist pattern 13 can be obtained with high shape following ability. A coating film 14 covering the upper surface of the mask layer 12 can be formed.

  As described above, in the deposition method such as the vapor deposition method or the sputtering method, for example, when the resist pattern is a hole pattern having a high aspect ratio, it is difficult to form a film on the bottom portion (particularly the end portion of the bottom portion). A film is formed only on the flat part and the corner part of the upper surface, and it is impossible to form an inversion layer that faithfully follows the shape of the resist pattern, and therefore it is impossible to accurately form a desired inversion pattern. There's a problem.

  On the other hand, with the atomic layer deposition method, for example, even when the concavo-convex shape has an aspect ratio of 2000 to 1, uniform film formation on the top surface, side surface, and bottom surface is possible. In general, the electron beam resist used in semiconductor-related lithography has an aspect ratio of about 3 to 1, and therefore, if the above-described atomic layer deposition method is used to form the coating film 14 as in the present invention, the figure is shown in FIG. As shown in FIG. 1C, a uniform coating film 14 that sufficiently follows the shape of the resist pattern 13 can be formed. Therefore, according to the present invention, the reverse pattern of the resist pattern 13 can be formed with high accuracy.

Here, as described above, since the atomic layer deposition method can form a thin film in units of atomic layers, it tends to have high film thickness controllability in addition to shape followability.
That is, when the atomic layer deposition method is used to form the coating film 14 as in the present invention, the coating formed on the top and side surfaces of the resist pattern 13 and the top surface of the hard mask layer 12 exposed from the resist pattern 13. The film 14 tends to increase in film thickness at the same film formation speed in any part.
Therefore, in the present invention, as shown in FIG. 1D, the thickness (T) of the coating film 14 formed on the upper surface of the resist pattern is equal to the opening dimension (W) on the bottom side of the resist pattern 13. A value of 1/2 or more is preferable.

The above reason will be described with reference to FIG.
FIG. 3 is an explanatory diagram of an example of a coating film formed using an atomic layer deposition method.
If the coating film formed using the atomic layer deposition method is formed in the same direction as described above, it is formed on the upper surface of the resist pattern 13, for example, as shown in FIG. When the thickness (T) of the coating film 14 is less than half the opening dimension (W) on the bottom side of the resist pattern 13, the thickness of the coating film 14 formed on the side surface of the resist pattern 13 is also The thickness of the central portion of the coating film 14 formed on the upper surface of the hard mask layer 12 in the opening of the resist pattern 13 is also the same value as T.

Then, as shown in FIG. 3B, after the coating film 14 is formed, the coating film 14 on the upper surface of the resist pattern 13 is removed by dry etching to expose the upper surface of the resist pattern 13. As described above, the thickness of the coating film 14 formed on the upper surface of the resist pattern 13 and the thickness of the central portion of the coating film 14 formed on the upper surface of the hard mask layer 12 in the opening of the resist pattern 13 are as follows. Because of the same thickness (T), the central portion of the hard mask layer 12 in the opening of the resist pattern 13 is also exposed.
That is, an undesired portion of the hard mask layer 12 is also exposed, and a desired pattern (an inverted pattern of the resist pattern 13) cannot be obtained.

  On the other hand, if the thickness (T) of the coating film 14 formed on the upper surface of the resist pattern is a value equal to or larger than ½ of the opening dimension (W) on the bottom side of the resist pattern 13, the opening of the resist pattern 13 is formed. Is filled with the coating film 14 grown from each of the two opposing side walls at the opening of the resist pattern 13, and therefore, after the coating film 14 is formed, the surface of the upper surface of the resist pattern 13 is covered by dry etching. Even if the covering film 14 is removed and the upper surface of the resist pattern 13 is exposed, the central portion of the hard mask layer 12 in the opening of the resist pattern 13 is not exposed.

  That is, when it is desired to fill the concave resist pattern with the coating film by using the atomic layer deposition method, in principle, the optimum value depends on the opening size of the concave portion of the resist pattern, regardless of the depth of the concave portion of the resist pattern. The film thickness of the coating film 14 is determined.

  Here, the film thickness (T) of the coating film 14 is preferably thinner. This is because the film formation time by the atomic layer deposition method can be shortened. Further, the thinner the film thickness (T) of the coating film 14 is in the subsequent process, that is, the process of removing the coating film 14 on the upper surface of the resist pattern 13 and exposing the upper surface of the resist pattern 13. Such time can be shortened.

In the present invention, after the coating film 14 is formed on the upper and side surfaces of the resist pattern 13 and the upper surface of the hard mask layer 12 exposed from the resist pattern 13, the coating formed on the upper surface of the resist pattern 13 is formed. The film 14 may be removed by surface polishing to expose the resist pattern 13.
In this case, since dry etching is not used to remove the coating film 14, even if the coating film 14 at a position higher than the upper surface of the resist pattern 13 is removed by polishing, it is lower than the upper surface of the resist pattern 13. The coating film 14 at the position remains, and therefore the hard mask layer 12 in the opening of the resist pattern 13 is not exposed including the central portion.
For the surface polishing, for example, chemical mechanical polishing (CMP) can be used.

  In the present invention, after the coating film 14 is formed on the upper surface and side surfaces of the resist pattern 13 and the upper surface of the hard mask layer 12 exposed from the resist pattern 13, the upper layer portion of the coating film 14 is subjected to surface polishing. Then, the resist film 13 may be exposed by removing the coating film 14 remaining on the upper surface of the resist pattern by dry etching.

For example, the surface step (center recess) of the coating film 14 shown in FIG. 3A is removed by surface polishing to flatten the surface, and then left on the upper surface of the resist pattern 13 by dry etching. The resist film 13 may be exposed by removing the covering film 14.
In this case, the thickness of the coating film 14 remaining on the upper surface of the resist pattern 13 by the surface polishing becomes thinner than the thickness of the central portion of the coating film 14 on the upper surface of the hard mask layer 12 in the opening of the resist pattern 13. Therefore, even if the coating film 14 remaining on the upper surface of the resist pattern 13 is removed by subsequent dry etching, the coating film 14 on the upper surface of the hard mask layer 12 in the opening of the resist pattern 13 remains. Therefore, the hard mask layer 12 in the opening of the resist pattern 13 is not exposed including the central portion.

Next, as shown in FIG. 2F, the exposed resist pattern 13 is removed. As a method of removing the resist pattern 13, for example, dry etching using oxygen gas can be used.
By this step, an inverted pattern composed of the coating film 14 remains on the hard mask layer 12.

Next, as shown in FIG. 2G, the hard mask layer 12 in an area exposed by removing the resist pattern 13 is etched to form a hard mask pattern 12a.
For example, when the substrate 11 is a synthetic quartz glass substrate, the hard mask layer 12 is a film containing chromium (Cr), and the coating film 14 is silicon oxide (SiO ₂ ), by dry etching using a chlorine-based gas, A hard mask pattern 12a can be formed.

Next, as shown in FIG. 2H, the substrate 11 exposed from the hard mask pattern 12a is etched to form an uneven transfer pattern 20.
For example, when the substrate 11 is a synthetic quartz glass substrate and the hard mask layer 12 is a film containing chromium (Cr), a fluorine-based gas (CF ₄ , CHF ₃ , C ₂ F _6, etc.), or these The concavo-convex shaped transfer pattern 20 can be formed by dry etching using the mixed gas.
Here, when the coating film 14 is silicon oxide (SiO ₂ ), the coating film 14 can also be removed by the etching process of the substrate 11 with the fluorine-based gas.
When the coating film 14 is made of a material other than a silicon-based material, the coating film 14 may be removed after the hard mask pattern 12a is formed. It may be performed after the pattern 20 is formed.

Finally, as shown in FIG. 2 (i), the hard mask pattern 12 a is removed to obtain the nanoimprint lithography template 10 of the present invention having the concavo-convex transfer pattern 20 on the main surface of the substrate 11.
The method for removing the hard mask pattern 12a may be wet etching in addition to dry etching. For example, when the hard mask layer 12 is a film containing chromium (Cr), the hard mask pattern 12a can be removed by wet etching using a ceric ammonium nitrate aqueous solution.

As described above, according to the present invention, a coating film is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern using an atomic layer deposition method, and the resist pattern is formed using this coating film. Since it is possible to form a pattern in which the unevenness is reversed, it is possible to obtain a reversal pattern having a high shape following property even for a shape having a high aspect ratio while preventing deformation of the resist pattern in the formation of the transfer pattern. .
Moreover, the resist drawing time can be shortened while using a positive resist even for a transfer pattern suitable for a negative resist like the above-described pillar pattern.
Therefore, according to the method for manufacturing a template for nanoimprint lithography according to the present invention, nanoimprint lithography having a transfer pattern accurately formed in a desired shape while achieving a reduction in manufacturing cost associated with shortening a drawing time. Templates can be manufactured.

(Second Embodiment)
Next, a second embodiment of the method for manufacturing a template for nanoimprint lithography according to the present invention will be described with reference to FIGS.
Here, FIG. 4 is a schematic process diagram showing an example of the first half of the method for manufacturing a template for nanoimprint lithography according to the present embodiment (second embodiment) of the present invention, and FIG. It is a schematic process drawing which shows an example of the subsequent process.

  A method for producing a template for nanoimprint lithography according to the present embodiment (second embodiment) of the present invention is a method for producing a template for nanoimprint lithography having a concavo-convex shaped transfer pattern on the main surface of the substrate. The resist pattern is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern by using a step of forming a resist pattern on the hard mask layer provided on the main surface and an atomic layer deposition method. Forming a first coating film covering the upper surface and side surfaces of the hard mask layer and the upper surface of the hard mask layer exposed from the resist pattern; and a second coating film on the first coating film And forming at least a part of the first coating film and the second coating film on the upper surface of the hard mask layer, and Removing the first coating film and the second coating film on the upper surface of the strike pattern to expose the resist pattern; removing the exposed resist pattern; and removing the resist pattern Etching the hard mask layer at the exposed portion to form a hard mask pattern, etching the substrate exposed from the hard mask pattern to form the uneven transfer pattern, and the hard And a step of removing the mask pattern in order.

  In the first embodiment described above, all of the coating film constituting the reverse pattern of the resist pattern is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern using the atomic layer deposition method. However, in the second embodiment, by using the atomic layer deposition method, the first coating that forms part of the reverse pattern of the resist pattern at a temperature lower than the glass transition temperature of the resin that forms the resist pattern. Although the cover film is formed, the second cover film constituting the remaining portion of the reversal pattern is formed by a method or condition different from the method of forming the first cover film.

As described above, the atomic layer deposition method can form a film at a low temperature and has high shape followability and film thickness controllability. However, it is necessary to increase the film thickness of the coating film. There is a disadvantage that the film takes time.
Therefore, in the present embodiment, first, the first coating film is formed at a low temperature using an atomic layer deposition method, and then the second coating film is applied by another method, for example, an SOG material. By using the forming method or the CVD method, it is possible to prevent the resist pattern from being deformed, and to obtain a reverse pattern of the resist pattern with high shape followability, while taking the above film formation time. Disadvantages are improved.

  For example, as shown in FIGS. 4A to 4C, also in this embodiment, a substrate 11 provided with a hard mask layer 12 on the main surface is prepared (FIG. 4A). A resist pattern 13 is formed on the mask layer 12 (FIG. 4B), and the resist pattern 13 is formed at a temperature lower than the glass transition temperature of the resin constituting the resist pattern 13 by using an atomic layer deposition method. Until the coating film (first coating film 15) covering the upper surface and side surfaces of the metal film and the upper surface of the hard mask layer 12 exposed from the resist pattern 13 is formed (FIG. 4C). It is the same process as the embodiment.

  However, in the present embodiment, as shown in FIG. 4D to FIG. 5E, after that, a step of forming a second coating film 16 on the first coating film 15 ( 4D), the first coating film 15 on the upper surface of the resist pattern 13 while leaving at least part of the first coating film 15 and the second coating film 16 on the upper surface of the hard mask layer 12. And the step of removing the second coating film 16 to expose the resist pattern 13 (FIG. 5E), which is different from the first embodiment described above.

Here, since the shape of the resist pattern 13 has already been accurately transferred by the previously formed first coating film 15, a high temperature is required for the subsequent formation of the second coating film 16. A film forming method such as a method of applying and forming an SOG material, a CVD method, or the like can also be used.
More specifically, as shown in FIG. 4C, the resist pattern 13 is covered with the first coating film 15 with a high shape following property, and thereafter, for example, the resin glass constituting the resist pattern 13 Even if the second coating film 16 is formed at a temperature higher than the transition temperature, the shape of the resist pattern 13 is maintained unless the first coating film 15 is deformed.

Further, as described above, since the shape of the resist pattern 13 has already been transferred with high accuracy by the first coating film 15 previously formed, the subsequent formation of the second coating film 16 requires atomic atoms. It is also possible to use a film forming method that is inferior in shape followability as compared with the layer deposition method, such as a vapor deposition method or a sputtering method.
More specifically, for example, even when the resist pattern 13 is a hole pattern with a high aspect ratio, the first coating film 15 formed by the atomic layer deposition method has a high shape following property and has a bottom portion (particularly a bottom portion). 2), the second coating film 16 formed by vapor deposition or sputtering is formed with a gap between the first coating film 15 and the first coating film 15, for example. However, if the first coating film 15 exists until the step of forming the hard mask pattern 12a is completed, the shape of the resist pattern 13 is maintained.

In the present embodiment, atomic layer deposition may be used to form the second coating film 16. In this case, for example, the second coating film 16 may be formed at a temperature different from the first coating film 15, for example, at a higher temperature, or different from the first coating film 15. The second coating film 16 may be formed using a gas containing an element.
This is because, by changing the film formation conditions and materials as described above, the film formation rate of the second coating film 16 can be made faster than that of the first coating film 15 and the like.

In addition, although the material which comprises the 2nd coating film 16 can be suitably selected according to a use, it is the same material system as the material which comprises the 1st coating film 15, and a process is simplified. It is preferable in that it can be performed. That is, the same etching conditions can be used for the removal of the first coating film 15 and the removal of the second coating film 16, and the process of the manufacturing method according to the present invention can be simplified.
For example, when the hard mask layer 12 is a film containing chromium (Cr), the material forming the first coating film 15 and the material forming the second coating film 16 are both made of a material containing silicon. It is preferable to be configured. The first coating film 15 and the second coating film 16 are removed by dry etching using a fluorine-based gas (CF ₄ , CHF ₃ , C ₂ F _6, etc.) or a mixed gas thereof. This is because it can be performed in the same process.

The second coating film 16 is formed using the method as described above (FIG. 4D), and then the first coating film 15 and the second coating film 16 on the upper surface of the hard mask layer 12 are formed. After removing the first coating film 15 and the second coating film 16 on the upper surface of the resist pattern 13 while leaving at least a part of the resist pattern 13 (FIG. 5E) By performing the same process as in the first embodiment, the nanoimprint lithography template 10 of the present invention can be obtained.
For example, the exposed resist pattern 13 is removed by dry etching using oxygen gas (FIG. 5F), and the hard mask layer 12 exposed by removing the resist pattern 13 is etched and hardened. A mask pattern 12a is formed (FIG. 5G), and the substrate 11 exposed from the hard mask pattern 12a is etched to form a portion that becomes the transfer pattern 20 (FIG. 5H). The mask pattern 12a is removed to obtain the nanoimprint lithography template 10 of the present invention having the uneven transfer pattern 20 on the main surface of the substrate 11 (FIG. 5 (i)).

  In this embodiment as well, as in the first embodiment described above, the second coating film 16 is formed on the first coating film 15 and then formed on the upper surface of the resist pattern 13. The first coating film 15 and the second coating film 16 may be removed by surface polishing to expose the resist pattern 13.

  Similarly, after forming the second coating film 16 on the first coating film 15, the surface layer is planarized by removing the upper layer portion of the second coating film 16 by surface polishing, Thereafter, the first coating film 15 and the second coating film 16 remaining on the upper surface of the resist pattern may be removed by dry etching to expose the resist pattern 13.

  As described above, according to the method for manufacturing a template for nanoimprint lithography according to the present embodiment (second embodiment) of the present invention, the resist pattern is prevented from being deformed, and the resist pattern is inverted with high shape followability. In addition, it is possible to shorten the film formation time of the coating films (first coating film and second coating film) for forming the reverse pattern.

  In the above description, the form in which the first coating film 15 and the second coating film 16 are formed as the coating film formed on the resist pattern 13 has been described. The coating film is not limited to two layers, and may be a multilayer film structure of three or more layers that further includes a coating film on the second coating film 16.

  As mentioned above, although each embodiment was described about the manufacturing method of the template for nanoimprint lithography concerning the present invention, the present invention is not limited to the above-mentioned 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 falls within the technical scope of the invention.

DESCRIPTION OF SYMBOLS 10 ... Template for nanoimprint lithography 11 ... Board | substrate 12 ... Hard mask layer 12a ... Hard mask pattern 13 ... Resist pattern 14 ... Coating film 15 ... 1st coating film 16 ... 2nd coating film 20 ... Transfer pattern 100 ... Template for nanoimprint lithography 111 ... Substrate 112 ... Hard mask layer 112a ... Hard mask pattern 113 ... Resist pattern 120 ... Transfer pattern 211 ... Substrate to be transferred 212 ... Resin 212a, 212b ... Resin pattern 230 ... UV 240 ... Reactive ion

Claims (6)

A method for producing a template for nanoimprint lithography having a concavo-convex transfer pattern on a main surface of a substrate,
Forming a resist pattern on a hard mask layer provided on the main surface of the substrate;
An atomic layer deposition method is used to cover the upper and side surfaces of the resist pattern and the upper surface of the hard mask layer exposed from the resist pattern at a temperature lower than the glass transition temperature of the resin constituting the resist pattern. Forming a cover film;
Removing the coating film on the top surface of the resist pattern while leaving the coating film covering the top surface of the hard mask layer by dry etching, and exposing the resist pattern;
Removing the exposed resist pattern;
Etching the hard mask layer at a portion exposed by removing the resist pattern to form a hard mask pattern;
Etching the substrate exposed from the hard mask pattern to form the uneven transfer pattern;
Removing the hard mask pattern;
In order,
In the step of forming the coating film, the thickness of the coating film formed on the upper surface of the resist pattern is ½ or more of the opening size on the bottom side of the resist pattern. Template manufacturing method.   2. The method according to claim 1, wherein the step of forming the coating film includes a step of alternately supplying a gas containing silicon and a gas containing one or more of oxygen, nitrogen, and fluorine. The manufacturing method of the template for nanoimprint of description. A method for producing a template for nanoimprint lithography having a concavo-convex transfer pattern on a main surface of a substrate,
Forming a resist pattern on a hard mask layer provided on the main surface of the substrate;
Using an atomic layer deposition method, a top surface and a side surface of the resist pattern and a top surface of the hard mask layer exposed from the resist pattern are covered at a temperature lower than the glass transition temperature of the resin constituting the resist pattern. Forming a coating film of 1;
Forming a second coating film on the first coating film;
The first coating film and the second coating on the upper surface of the resist pattern while leaving at least part of the first coating film and the second coating film on the upper surface of the hard mask layer Removing the film to expose the resist pattern;
Removing the exposed resist pattern;
Etching the hard mask layer at a portion exposed by removing the resist pattern to form a hard mask pattern;
Etching the substrate exposed from the hard mask pattern to form the uneven transfer pattern;
Removing the hard mask pattern;
In order,
The step of forming the second coating film is a film forming step using an atomic layer deposition method, and the step of forming the second coating film at a temperature different from that of the first coating film A method for producing a template for nanoimprint lithography, wherein: A method for producing a template for nanoimprint lithography having a concavo-convex transfer pattern on a main surface of a substrate,
Forming a resist pattern on a hard mask layer provided on the main surface of the substrate;
Using an atomic layer deposition method, a top surface and a side surface of the resist pattern and a top surface of the hard mask layer exposed from the resist pattern are covered at a temperature lower than the glass transition temperature of the resin constituting the resist pattern. Forming a coating film of 1;
Forming a second coating film on the first coating film;
The first coating film and the second coating on the upper surface of the resist pattern while leaving at least part of the first coating film and the second coating film on the upper surface of the hard mask layer Removing the film to expose the resist pattern;
Removing the exposed resist pattern;
Etching the hard mask layer at a portion exposed by removing the resist pattern to form a hard mask pattern;
Etching the substrate exposed from the hard mask pattern to form the uneven transfer pattern;
Removing the hard mask pattern;
In order,
The step of forming the second coating film is a film forming process using an atomic layer deposition method, and the second coating film is formed using a gas containing an element different from that of the first coating film. A method for producing a template for nanoimprint lithography, which is a step of forming a film.   The step of forming the first coating film includes a step of alternately supplying a gas containing silicon and a gas containing one or more of oxygen, nitrogen, and fluorine. A method for producing a template for nanoimprint lithography according to claim 3 or 4.   The method for producing a template for nanoimprint lithography according to claim 3, wherein the second coating film is made of a material containing silicon.

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