TECHNICAL FIELD

The present invention relates to a template used in nanoimprint lithography transferring a fine transfer pattern onto a resin formed on a transfer substrate, and a template blank used of producing the template. In addition, the present invention also relates to a template used in nanoimprint lithography transferring a fine transfer pattern onto a resin formed on a transfer substrate, and more particularly to a production method of a template substrate for imprinting having a first step structure on a main surface of a base, a second step structure on the first step structure, and a light shielding film on an upper surface of the first step structure, a production method of a template for imprinting, and a template used in the production methods.

BACKGROUND ART

Nanoimprint lithography is known as a technology for transferring and forming a fine pattern, for example, in the production of a device for semiconductor.

The above nanoimprint lithography is a technique in which a template (also referred to as a mold or a stamper) for imprinting having a fine concavo-convex shape transfer pattern formed on a surface thereof is brought into contact with a resin formed on a transfer substrate such as a semiconductor wafer, after that, the resin is cured, and the concavo-convex shape (more specifically, the concavo-convex inverted shape) of the transfer pattern of the template is transferred onto the resin.

As a method of nanoimprint lithography, there are a thermal imprinting method of curing a resin by heating and a photo imprinting method of curing a resin by light exposure. For applications requiring high positioning accuracy, a photo imprinting method that is not affected by expansion or contraction due to heating is mainly used (for example, Patent Documents 1 and 2).

In the template used for nanoimprint lithography as described above, a mesa-shaped step structure is provided on the main surface of the base so that only a predetermined region (referred to as a transfer pattern region) in which a transfer pattern in a concavo-convex shape is formed is in contact with the resin formed on the transfer substrate, and the transfer pattern is formed on the upper surface of the mesa-shaped step structure (for example, Patent Document 3). Incidentally, in the template having such a structure, the upper surface of the mesa-shaped step structure becomes the transfer pattern region.

The step difference (height from the main surface of the base to the upper surface of the step structure) of the mesa-shaped step structure as described above is determined, for example, by the mechanical precision of the imprinting apparatus to be used. However, the step difference requires typically about 30 μm.

In addition, in nanoimprint lithography, as the number of transfer patterns is increased, the adhesion area between the template and the resin is increased, so that a force against the frictional force between the template and the resin is required for releasing. In particular, since transfer patterns for semiconductor applications are small in size and high in pattern density, a large force is required for releasing.

Therefore, there has been proposed a method in which, by forming the depression part on the back surface side (the side opposite to the side on which the transfer pattern is formed) of the template, the thickness of the template in a predetermined region (region including the transfer pattern region) where the transfer pattern is formed is reduced to facilitate the bending, and during releasing, by bending the transfer pattern region of the template convexly toward the transfer substrate side, the template is partly released sequentially from the outer edge part of the transfer region (for example, Patent Document 4).

CITATION LIST

Patent Document

Patent Document 1: JP 2004-504718 APatent Document 2: JP 2002-93748 APatent Document 3: JP 2014-56893 APatent Document 4: JP 2009-536591 APatent Document 5: JP 2007-103924 A

SUMMARY OF INVENTION

Technical Problem

In the above-described photo imprinting method, in order to suppress unintended curing of the resin in the non-transfer region during the imprinting, it has been proposed to provide a light shielding member to a non-pattern part (a part different from the transfer pattern region) of the template (for example, Patent Document 5).

However, it is usually difficult to uniformly provide the light shielding member on the side surface of the mesa-shaped step structure as illustrated inFIGS. 9(A), 7(B), and7(D) of Patent Document 5. Patent Document 5 also does not disclose details of the production method of obtaining the above-described form as illustrated inFIGS. 9(A), 7(B), and7(D).

In addition, in the form in which the light shielding member is provided only on the main surface of the base as illustrated inFIG. 9(C)of Patent Document 5, for example, as described above, in a case where there is a step difference of about 30 μm between the upper surface of the mesa-shaped step structure and the main surface of the base, the exposure light leaking from the part where the mesa-shaped step structure and the main surface of the base are in contact with each other spreads and is emitted onto the resin according to the distance of the step difference, so that there is also a problem that the resin at an unintended part is cured.

In particular, since it takes time for dry etching to form a mesa-shaped step structure with a step difference of about 30 μm, the step structure is usually formed by wet etching. Therefore, the cross-sectional shape of the part where the mesa-shaped step structure and the main surface of the base are in contact with each other is hard to be a right angle, and the cross-sectional shape becomes the rounded shape. Then, in the rounded shape part (the part where the mesa-shaped step structure and the main surface of the base are in contact with each other), it is difficult to form the light shielding member with the same thickness as the other parts, and thus, the exposure light easily leaks.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a template and a template blank and a production method of a template substrate for imprinting for producing a template for imprinting, a production method of a template for imprinting, and a template used for the production methods capable of suppressing influence of leakage of exposure light (irradiation to an unintended region) during imprinting while maintaining a required height (distance from a main surface of a base) of a transfer pattern region.

Solution to Problem

That is, according to the present invention, there is provided a template to be used for imprint lithography transferring a transfer pattern in a concave and convex structure to a resin on a transfer substrate, the template characterized by comprising: on a main surface of abase, a first step structure, a second step structure on the first step structure, and the transfer pattern at an upper surface of the second step structure; wherein an outer side region of the second step structure at an upper surface of the first step structure is covered with a light shielding film.

According to the present invention, there is provided a template to be used for imprint lithography transferring a transfer pattern in a concave and convex structure to a resin on a transfer substrate, the template characterized by comprising: on a main surface of a base, a first step structure, a second step structure on the first step structure, and at an upper surface of the second step structure, a first concave and convex structure body configuring the transfer pattern, and a second concave and convex structure body configuring an alignment mark; wherein an outer side region of the second step structure at an upper surface of the first step structure is covered with a light shielding film; and a high contrast film configured by a film of a different material from a material configuring the base, is formed on the light shielding film and on a bottom surface of a concave part in the second concave and convex structure body.

In the invention, when a distance in a vertical direction from the main surface of the base to an upper surface of the light shielding film on the first step structure is regarded as H1, and a distance in a vertical direction from a main surface of the base to a bottom surface of a concave part in the transfer pattern at an upper surface of the second step structure is regarded as H2, a relation: H1<H2is preferably satisfied.

In the invention, when a distance in a vertical direction from the main surface of the base to an upper surface of the light shielding film on the first step structure is regarded as H1, a distance in a vertical direction from the main surface of the base to an upper surface of the second step structure is regarded as H3,a distance in a horizontal direction from an outer edge of the main surface of the base to an outer edge of an upper surface of the first step structure is regarded as D1, and a distance in a horizontal direction from the outer edge of the main surface of the base to an outer edge of the upper surface of the second step structure is regarded as D2, a relation: H1≤H3×(D1/D2) is preferably satisfied.

The invention further preferably comprises a depression part including the second step structure at an opposite side surface to the main surface of the base in a planar view.

In the invention, the depression part preferably includes the first step structure in a planar view.

In the invention, a transmittance of the light shielding film with a wave length of 365 nm is preferably 10% or less.

According to the present invention, there is provided a template blank for producing a template to be used for imprint lithography transferring a transfer pattern in a concave and convex structure to a resin on a transfer substrate, the template blank characterized by comprising: on a main surface of a base, a first step structure, a second step structure on the first step structure; wherein an outer side region of the second step structure at an upper surface of the first step structure is covered with a light shielding film.

In the invention, when a distance in a vertical direction from the main surface of the base to an upper surface of the light shielding film on the first step structure is regarded as H1, and a distance in a vertical direction from the main surface of the base to an upper surface of the second step structure is regarded as H4, a relation: H1<H4is preferably satisfied.

In the invention, when a distance in a vertical direction from the main surface of the base to an upper surface of the light shielding film on the first step structure is regarded as H1, a distance in a vertical direction from the main surface of the base to an upper surface of the second step structure is regarded as H4, a distance in a horizontal direction from an outer edge of the main surface of the base to an outer edge of an upper surface of the first step structure is regarded as D1, and a distance in a horizontal direction from the outer edge of the main surface of the base to an outer edge of the upper surface of the second step structure is regarded as D2, a relation: H1≤H4×(D1/D2) is preferably satisfied.

The invention further preferably comprises a depression part including the second step structure at an opposite side surface to the main surface of the base in a planar view.

In the invention, the depression part preferably includes the first step structure in a planar view.

In the invention, a transmittance of the light shielding film with a wave length of 365 nm is preferably 10% or less.

According to the present invention, there is provided a production method of a template substrate for imprinting, the template substrate including a first step structure on a main surface of a base, a second step structure on the first step structure, and a light shielding film on an upper surface of the first step structure, the production method characterized by comprising steps of: a multistep template substrate with a light shielding material layer preparing step of preparing a multistep template substrate with a light shielding material layer including the first step structure, the second step structure, and a light shielding material layer on an upper surface of the first step structure and on an upper surface of the second step structure; a resin layer forming step of forming a first resin layer on the light shielding material layer formed on the upper surface of the first step structure, and forming a second resin layer thinner than a thickness of the first resin layer, on the light shielding material layer formed on the upper surface of the second step structure; a second resin layer removing step of removing the second resin layer while leaving the first resin layer by dry etching; and a light shielding film forming step of etching the light shielding material layer using the first resin layer left as a mask to remove the light shielding material layer formed on the upper surface of the second step structure while leaving the light shielding material layer formed on the upper surface of the first step structure; in this order, wherein the resin layer forming step includes: a resin thickness specifying step of, using a template for specifying resin thickness including a concave part in a main surface side contacting a resin, pushing an upper surface of an outer peripheral part of the concave part in the template for specifying resin thickness against a first resin dropped onto the light shielding material layer formed on the upper surface of the first step structure, and pushing a bottom surface of the concave part in the template for specifying resin thickness against a second resin dropped onto the light shielding material layer formed on the upper surface of the second step structure; and a depth of the concave part in the template for specifying resin thickness is smaller than a height from the upper surface of the first step structure to the upper surface of the second step structure.

In the invention, the resin layer forming step preferably includes: the resin thickness specifying step, and a resin curing step of irradiating an ultraviolet ray for curing the first resin and the second resin in a state the template for specifying resin thickness is pushed against, to form the first resin layer and the second resin layer.

In the invention, the multistep template substrate with a light shielding material layer preparing step is preferably provided with: a multistep template substrate preparing step of preparing a multistep template substrate including the first step structure and the second step structure; and a light shielding material layer forming step of forming a light shielding material layer on the upper surface of the first step structure and on the upper surface of the second step structure; in this order.

In the invention, the multistep template substrate preparing step is preferably provided with: a one step template substrate preparing step of preparing a one step template substrate including a one step structure on the main surface of the base; an etching mask forming step of forming an etching mask in a region becoming a transfer pattern region at an upper surface of the step structure in the one step template substrate; and a multistep forming step of forming a first step structure as a bottom step and a second step structure as an upper step by etching the step structure using the etching mask.

According to the present invention, there is provided a production method of a template for imprinting, the template including a first step structure on a main surface of a base, a second step structure on the first step structure, a light shielding film on an upper surface of the first step structure, and a transfer pattern in a concave and convex structure at an upper surface of the second step structure, the production method characterized by comprising steps of: a multistep template with a light shielding material layer preparing step of preparing a multistep template with a light shielding material layer including the first step structure, the second step structure, a transfer pattern in a concave and convex structure at the upper surface of the second step structure and a light shielding material layer on an upper surface of the first step structure and on an upper surface of the second step structure; a first and second resin layer forming step of forming a first resin layer on the light shielding material layer formed on the upper surface of the first step structure, and forming a second resin layer thinner than a thickness of the first resin layer, on the light shielding material layer formed on the upper surface of the second step structure; a second resin layer removing step of removing the second resin layer while leaving the first resin layer by dry etching; and a light shielding film forming step of etching the light shielding material layer using the first resin layer left as a mask to remove the light shielding material layer formed on the upper surface of the second step structure while leaving the light shielding material layer formed on the upper surface of the first step structure; in this order, wherein the first and second resin layer forming step includes: a first and second resin thickness specifying step of, using a template for specifying first and second resin thickness including a concave part in a main surface side contacting a resin, pushing an upper surface of an outer peripheral part of the concave part in the template for specifying first and second resin thickness against a first resin dropped onto the light shielding material layer formed on the upper surface of the first step structure, and pushing a bottom surface of the concave part in the template for specifying first and second resin thickness against a second resin dropped onto the light shielding material layer formed on the upper surface of the second step structure; and a depth of the concave part in the template for specifying first and second resin thickness is smaller than a height from the upper surface of the first step structure to the upper surface of the second step structure.

According to the present invention, there is provided a production method of a template for imprinting, the template including a first step structure on a main surface of a base, a second step structure on the first step structure, a light shielding film on an upper surface of the first step structure, and a transfer pattern in a concave and convex structure on an upper surface of the second step structure, the production method characterized by comprising steps of: a multistep template with a light shielding material layer preparing step of preparing a multistep template with a light shielding material layer including: the first step structure, the second step structure; a first concave and convex structure body configuring the transfer pattern and a second concave and convex structure body configuring an alignment mark, at an upper surface of the second step structure; and a light shielding material layer on the upper surface of the first step structure and on the upper surface of the second step structure; a first and second resin layer forming step of forming a first resin layer on the light shielding material layer formed on the upper surface of the first step structure, and forming a second resin layer thinner than a thickness of the first resin layer, on the light shielding material layer formed on the upper surface of the second step structure; a second resin layer removing step of removing the second resin layer while leaving the first resin layer by dry etching; a light shielding film forming step of forming a light shielding layer on the upper surface of the first step structure by etching the light shielding material layer using the first resin layer left as a mask to remove the light shielding material layer formed on the upper surface of the second step structure while leaving the light shielding material layer formed on the upper surface of the first step structure; a high contrast layer forming step of forming a high contrast layer on the light shielding material layer, on an upper surface of a convex part and on a bottom surface of a concave part in the first concave and convex structure body, as well as on an upper surface of a convex part and on a bottom surface of a concave part in the second concave and convex structure body; a third to fifth resin layer forming step of forming a third resin layer on the high contrast layer formed on the light shielding film, forming a fourth resin layer thinner than a thickness of the third resin layer on the high contrast layer formed on the upper surface of the convex part and the bottom surface of the concave part in the first concave and convex structure body, and forming a fifth resin layer thicker than a thickness of the fourth resin layer on the high contrast layer formed on the upper surface of the convex part and on the bottom surface of the concave part in the second concave and convex structure; a fourth resin layer removing step of removing the fourth resin layer while leaving the third resin layer and the fifth resin layer by dry etching; and a high contrast film forming step of etching the high contrast layer using the third resin layer and the fifth resin layer left as a mask to remove the high contrast layer formed on the upper surface of the convex part and the bottom surface of the concave part in the first concave and convex structure body as well as on the upper surface of the convex part in the second concave and convex structure body while leaving the high contrast layer formed on the light shielding film, and on the bottom surface of the concave part in the second concave and convex structure body; in this order, wherein the first and second resin layer forming step includes: a first and second resin thickness specifying step of, using a template for specifying first and second resin thickness including a concave part in a main surface side contacting a resin, pushing an upper surface of an outer peripheral part of the concave part in the template for specifying first and second resin thickness against a first resin dropped onto the light shielding material layer formed on the upper surface of the first step structure, and pushing a bottom surface of the concave part in the template for specifying first and second resin thickness against a second resin dropped onto the light shielding material layer formed on the upper surface of the second step structure; a depth of the concave part in the template for specifying first and second resin thickness is smaller than a height from the upper surface of the first step structure to the upper surface of the second step structure; the third to fifth resin layer forming step includes: a third to fifth resin thickness specifying step of, using a template for specifying third to fifth resin thickness including a concave part in a main surface side contacting a resin, and a depression formed at a bottom surface side of the concave part, pushing an upper surface of an outer peripheral part of the concave part in the template for specifying third to fifth resin thickness against a third resin dropped onto the high contrast layer formed on the light shielding film, pushing a bottom surface of the concave part in the template for specifying third to fifth resin thickness against a fourth resin dropped onto the high contrast layer formed on the upper surface of the convex part and on the bottom surface of the concave part in the first concave and convex structure body as well as against a fifth resin dropped onto the high contrast layer formed on the upper surface of the convex part and the bottom surface of the concave part in the second concave and convex structure body, and pushing a bottom surface of the depression against the fifth resin; and a depth of the concave part in the template for specifying third to fifth resin thickness excluding the depression part is smaller than a height from the upper surface of the high contrast layer formed on the light shielding film to the upper surface of the high contrast layer formed on the bottom surface of the concave part in the first concave and convex structure body.

In the invention, the first and second resin layer forming step preferably includes: the first and second resin thickness specifying step; and a first and second resin curing step of irradiating an ultraviolet ray for curing the first resin and the second resin in a state the template for specifying first and second resin thickness is pushed against, to form the first resin layer and the second resin layer.

In the invention, the multistep template with a light shielding material layer preparing step is preferably provided with: a multistep template preparing step of preparing a multistep template including the first step structure, the second step structure, and the transfer pattern at an upper surface of the second step structure; and a light shielding material layer forming step of forming a light shielding material layer on the upper surface of the first step structure and on the upper surface of the second step structure; in this order.

In the invention, the multistep template preparing step is preferably provided with: a one step template preparing step of preparing a one step template including a one step structure on the main surface of the base and the transfer pattern at the upper surface of the step structure; an etching mask forming step of forming an etching mask in a region at the upper surface of the step structure in the one step template where the transfer pattern is formed; and a multistep forming step of forming a first step structure as a bottom step and a second step structure as an upper step by etching the step structure using the etching mask; in this order.

In the invention, the multistep template with light shielding material layer preparing step is preferably provided with: a multistep template preparing step of preparing a multistep template including the first step structure, the second step structure, and the transfer pattern at an upper surface of the second step structure; and a light shielding material layer forming step of forming a light shielding material layer on the upper surface of the first step structure and on the upper surface of the second step structure; in this order; and the multistep template preparing step is provided with: a one step template substrate preparing step of preparing a one step template substrate including a one step structure on the main surface of the base; an etching mask forming step of forming an etching mask in a region becoming the transfer pattern at an upper surface of the step structure in the one step template substrate; a multistep forming step of forming a first step structure as a bottom step and a second step structure as an upper step by etching the step structure using the etching mask; and a transfer pattern forming step of forming the transfer pattern at the upper surface of the second step structure; in this order.

According to the present invention, there is provided a template characterized by comprising a concave part in a main surface side contacting a resin.

According to the present invention, there is provided a template characterized by comprising a concave part in a main surface side contacting a resin, and a depression formed at a bottom surface side of the concave part.

The present invention further preferably comprises a mark for position matching at the main surface side.

Preferably, the invention further comprises a mark for position matching at the main surface side, wherein the mark for position matching is a depression formed at an outer side of the concave part in the main surface, and a depth of the depression formed at a bottom surface side of the concave part and the depth of the depression formed at the outer side of the concave part are the same.

In the invention, the bottom surface size of the concave part is preferably 10 mm×10 mm or more and 70 mm×70 mm or less.

In the invention, the depth of the concave part is preferably 0.3 μm or more and 10 μm or less.

Preferably, the invention is used in the production method of a template substrate for imprinting and the depth of the concave part is smaller than a height from the upper surface of the first step structure to the upper surface of the second step structure in the template substrate for imprinting.

In the invention, the bottom surface of the concave part preferably is in a size enclosing the upper surface of the second step structure in the template substrate for imprinting.

In the invention, a region surrounded by the outer edge of the upper surface of the outer peripheral part of the concave part is preferably: in a shape and an area same as those of a region surrounded by the outer edge of the upper surface of the first step structure in the template substrate for imprinting; or in a size enclosing the region surrounded by the outer edge of the upper surface of the first step structure in the template substrate for imprinting.

Preferably, the invention is used in the production method of a template for imprinting, and the depth of the concave part is smaller than a height from the upper surface of the first step structure to the upper surface of the second step structure in the template for imprinting.

In the invention, a bottom surface of the concave part is preferably in a size enclosing the upper surface of the second step structure in the template for imprinting.

In the invention, a region surrounded by an outer edge of an upper surface of an outer peripheral part of the concave part is preferably: in a shape and an area same as those of a region surrounded by an outer edge of an upper surface of the first step structure in the template for imprinting; or in a size enclosing the region surrounded by the outer edge of the upper surface of the first step structure in the template for imprinting.

Advantageous Effects of Invention

In the template according to the present invention, it is possible to suppress the influence of the leakage of exposure light (irradiation to an unintended region) during the imprinting while maintaining the required height (the distance from the main surface of the base) of the transfer pattern region.

In addition, it is possible to easily produce the above-described template by using the template blank according to the present invention.

According to a production method of a template substrate for imprinting of the present invention, it is possible to produce a template substrate for imprinting having a first step structure on a main surface of a base, having a second step structure on the first step structure, and having a light shielding film on an upper surface of the first step structure without generating a defective part or a thin film part in the light shielding film.

In addition, according to a production method of a template for imprinting of the present invention, it is possible to produce a template for imprinting having a first step structure on a main surface of a base, having a second step structure on the first step structure, having a light shielding film on an upper surface of the first step structure, and having a transfer pattern in a concave and convex structure on an upper surface of the second step structure without generating a defective part or a thin film part in the light shielding film.

Then, in the template for imprinting produced by the production method of the template for imprinting according to the present invention, it is possible to suppress influence of leakage of exposure light (irradiation to an unintended region) during imprinting while maintaining a required height (a distance from the main surface of the base) of the transfer pattern region.

In addition, by using the template substrate for imprinting produced by the production method of the template substrate for imprinting according to the present invention, it is possible to easily produce the template for imprinting as described above.

