JP2016122782A - Method of manufacturing substrate, mask blank, and imprint mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a substrate, in which an imprint mold fixed to a fixture of a transfer device and capable of accurately transferring a mold pattern to an object to be transferred is suitably manufactured.SOLUTION: In a method of manufacturing a substrate, after a recess is formed in a recess forming area on one main surface of the substrate equipped with two main surfaces, an etching mask film is formed on a pedestal structure forming region on the other main surface of the substrate, and in a state where a substrate abutting part of a fixture is made to abut on the inside of the recess to support the substrate, the substrate is immersed into etching liquid to perform wet etching and form the pedestal structure in the pedestal structure forming region.SELECTED DRAWING: Figure 1

Description

  The present invention is applied to the production of a fine circuit pattern of a semiconductor device, the production of an optical component to which an optical function is added by the fine pattern, and the formation of a fine pattern of a magnetic recording layer in a magnetic recording medium (magnetic disk) mounted on a hard disk drive or the like. The present invention relates to a method for producing an imprint mold, a method for producing a substrate suitably used for the production, and a method for producing a mask blank.

  In order to transfer a large amount of the same fine pattern in the production of a fine circuit pattern of a semiconductor device, the production of an optical component to which an optical function is added by the fine pattern, and the fine pattern formation of a magnetic recording layer in a magnetic recording medium mounted on a hard disk drive or the like The imprint method has been used.

  In the imprint method, an imprint mold (stamper) in which a fine mold pattern is formed is used as an original plate, and the imprint mold is directly pressed against a liquid resin such as a photocurable resin applied on a transfer object. In this method, the mold pattern is transferred to a cured liquid resin by curing with ultraviolet rays or the like. For this reason, according to the imprint method, it is possible to transfer a large amount of the same fine pattern.

  Thus, since the imprint mold serves as an original for transferring a large amount of the same fine pattern, the dimensional accuracy of the mold pattern formed on the mold directly affects the dimensional accuracy of the produced fine pattern. In addition, since the imprint mold transfers the pattern by directly pressing the liquid resin applied on the transfer object, the cross-sectional shape of the mold pattern greatly affects the shape of the fine pattern to be produced. As the degree of integration of semiconductor devices and the like increases, the required pattern dimensions become smaller and the pattern transfer is performed at the same magnification. Therefore, higher imprint mold accuracy is required. ing.

As disclosed in Patent Document 1, an imprint mold having a structure in which a transfer pattern is formed on a pedestal structure (also referred to as a mesa structure) provided at the center of the main surface of a substrate is used. It is often done. This pedestal structure is provided so that the region other than the transfer region where the mold pattern is provided on the main surface does not come into contact with the substrate (semiconductor substrate or the like) or liquid resin of the transfer object.

As an aspect of the imprint mold, for example, one disclosed in Patent Document 2 is known. This imprint mold has a configuration in which a concave portion is provided on the back main surface opposite to the front main surface on which the mold pattern is formed. Furthermore, since the concave portion is provided, the thickness of the substrate in the region including the pedestal structure where the mold pattern is formed on the main surface is thinner than the surrounding region. When the mold pattern of this imprint mold is pressed against a liquid resin such as a photo-curing resin applied to the transfer object, the substrate is thinner than the surroundings by increasing the air pressure in the recess. It is curved in the direction in which the mold pattern in the area is widened. When the mold pattern is pressed against the liquid resin in this state, the center side of the mold pattern first comes into contact with the liquid resin, and the area where the mold pattern and the liquid resin come into contact with each other starts from the concentric circle toward the outer periphery. Since it spreads in the shape, it can suppress that air is enclosed between a mold pattern and liquid resin.

Also, when the mold is peeled after the liquid resin is cured, the mold pattern in the area where the thickness of the substrate is thinner than the surroundings is increased by increasing the air pressure in the recess. To bend. Thereby, it becomes easy to peel (release) the mold pattern (imprint mold) from the cured liquid resin.

When manufacturing such an imprint mold in which a concave portion is provided on the main surface on the back side, as disclosed in FIG. 6 and the like of Patent Document 3, a fine pattern is first formed on the main surface on the front side of the substrate. Conventionally, after forming a mold pattern, a pedestal structure is formed, and a manufacturing method in which a recess on the back surface is formed is generally used. On the other hand, Patent Document 3 discloses a method of manufacturing an imprint mold using a base structure and a recess formed in advance on both main surfaces of a substrate.

JP 2009-98689 A Special table 2009-536591 JP 2014-56893 A

The height of the pedestal structure formed on the main surface of the substrate used for manufacturing the imprint mold is significantly higher than the digging depth of the mold pattern, for example, about 30 μm. Further, the processing accuracy of the base structure is not required to be as high as the processing accuracy of the mode pattern. For this reason, in the step of forming the base structure, dry etching is generally not applied, but wet etching using hydrofluoric acid or the like having a high etching rate is generally applied. The process of forming this pedestal structure is performed by the following processes, for example.

That is, first, an etching mask film having etching selectivity with respect to the wet etching solution is provided in a region where the base structure of the main surface of the substrate such as glass is formed. Next, the substrate provided with the etching mask film is immersed in a wet etching solution, and the substrate is wet etched until a pedestal structure having a predetermined height is formed. Then, the substrate on which the pedestal structure is formed is pulled up from the wet etching solution, and the etching mask film is peeled off.
Further, a recess is formed by machining on the main surface on the back side opposite to the main surface on the front side where the pedestal structure is formed.

By the way, when the imprint mold manufactured in this way is fixed to the fixing jig of the transfer device, all four end surfaces are sandwiched. Further, the main surface other than the region where the concave portion on the back side is formed is also fixed to the fixing jig of the transfer device. For this reason, the flatness required for the end face of the substrate of the imprint mold is stricter than the flatness required for the end face of the substrate of the transfer mask used for pattern transfer by photolithography. Also, the parallelism between the two opposing end faces is stricter than the parallelism required for the end face of the substrate of the transfer mask used for pattern transfer by photolithography.

Since wet etching for forming the pedestal structure on the substrate takes time, the etching solution must be circulated uniformly. The wet etching step of immersing the substrate in the wet etching solution is performed with the substrate supported by a support. Etching is less likely to proceed at the portion where the substrate support portion of the support is in contact with the substrate or at the region of the surface of the substrate adjacent to the support portion as compared to other surfaces. For this reason, it is preferable that the board | substrate support part of a support tool supports a board | substrate in the position with little influence on the wet etching which forms a base structure.

However, when performing wet etching to form a pedestal structure using a support tool that supports the substrate at a part of the end surface of the substrate, which is a support location where the influence of wet etching is relatively small, or the main surface near the end surface, There is a problem that a step is generated on the end surface of the substrate or the main surface in the vicinity of the end surface, and it is difficult to ensure the quality of flatness and parallelism required for the substrate end surface. It is possible to apply a method in which the size of the main surface of the substrate is made larger than the size required for the finished product, and the portion where the step is generated is cut and molded. However, in addition to an increase in the number of manufacturing processes, there is a problem that a possibility that a defect such as a new scratch is generated at the time of a cutting process, a polishing process after cutting, or the like is increased. Furthermore, it is necessary to increase the processing accuracy of the end face of the substrate after cutting, which increases the manufacturing burden.

Therefore, the present invention has been made in view of such a conventional problem, and the object of the present invention is to fix the mold pattern to the transfer object with high accuracy by first fixing it to the fixing jig of the transfer device. It is to provide a manufacturing method of a substrate suitable for manufacturing an imprint mold that can be transferred, and secondly, to provide a manufacturing method of a mask blank using a substrate obtained by the manufacturing method of this substrate. Third, an imprint mold that is manufactured using a mask blank obtained by this mask blank manufacturing method, can be fixed to a fixing jig of a transfer device, and can accurately transfer a mold pattern to a transfer object. It is to provide a manufacturing method.

As a result of earnest verification to solve the above problems, the present inventor first performed a step of forming a recess on the main surface on the back side of the substrate before the step of forming the base structure on the main surface on the front side of the substrate. Then, at the time of the wet etching step of forming the base structure on the main surface on the front side of the substrate, the substrate contact portion of the support for supporting the substrate was previously formed on the main surface on the back side. The substrate is supported by a support tool so as to contact the inner surface of the recess, and the substrate supported by the support tool is immersed in a wet etching solution to form a pedestal structure on the main surface on the front side of the substrate. I came to the conclusion that I should do it.
That is, in order to solve the above problems, the present invention has the following configuration.

(Configuration 1)
A step of preparing a substrate having two main surfaces, a step of forming a recess in a recess forming region on one main surface of the substrate, and a base structure forming region on the other main surface of the substrate, against an etching solution Forming an etching mask film having etching selectivity with the substrate; and contacting the substrate abutting portion of a support for supporting the substrate with the inner surface of the recess. A step of immersing the substrate in the etching solution in a state where the substrate is formed and performing wet etching on the substrate to form a pedestal structure in the pedestal structure formation region. This is a method for manufacturing a substrate.

(Configuration 2)
The support includes a substrate support portion having at least one substrate contact portion, and supports the substrate by bringing the substrate contact portion into contact with an inner side wall surface or a bottom surface of the recess. This is a method for manufacturing a substrate according to Configuration 1.
(Configuration 3)
The step of forming the etching mask film on the pedestal structure forming region of the substrate includes a step of forming the etching mask film on the other main surface of the substrate and a resist in the pedestal structure forming region on the etching mask film. Or a step of forming a film, and a step of performing etching using the resist film as a mask on the etching mask film to remove the etching mask film other than the base structure forming region. 2. The method for producing a substrate according to 2.

(Configuration 4)
4. The method for manufacturing a substrate according to any one of Structures 1 to 3, further comprising a step of removing the etching mask film after the step of forming the pedestal structure.
(Configuration 5)
5. The substrate manufacturing method according to any one of Structures 1 to 4, wherein the substrate is made of glass, and the etching solution contains hydrofluoric acid.

(Configuration 6)
6. The substrate manufacturing method according to any one of Structures 1 to 5, wherein the etching mask film is formed of a material containing chromium.
(Configuration 7)
7. The method for manufacturing a substrate according to any one of Structures 1 to 6, wherein the recess forming region is a region having a size including the pedestal structure forming region.

(Configuration 8)
The position of the center of the substrate is coincident with the position of the center of the recess, or the shift between the positions of these two centers is 100 μm or less. It is a manufacturing method.
(Configuration 9)
The substrate according to any one of Structures 1 to 8, wherein a position of a center of the substrate is coincident with a position of a center of the pedestal structure, or a deviation between positions of the two centers is 100 μm or less. It is a manufacturing method.

(Configuration 10)
The step of forming the recess in the recess forming region on one main surface of the substrate includes a flat plate-like first base material having at least one hole having a predetermined shape, and at least one flat plate shape. A substrate manufacturing method according to any one of Configurations 1 to 9, wherein a concave portion including the hole is formed in a concave portion forming region of the substrate after bonding by bonding the second base material. is there.

(Configuration 11)
The substrate is a substrate used for manufacturing an imprint mold, and the main surface on which the concave portion is formed is a surface that is chucked by a mold holding portion of a transfer device that transfers a mold pattern. It is a manufacturing method of the board | substrate in any one of the structures 1 thru | or 10 characterized.
(Configuration 12)
12. The substrate manufacturing method according to Configuration 11, wherein the pedestal structure forming region is a region where a mold pattern is formed at the time of manufacturing an imprint mold.

(Configuration 13)
A mask blank comprising a step of forming a pattern forming thin film on a main surface of a substrate manufactured by the substrate manufacturing method according to any one of Configurations 1 to 12 on which the pedestal structure is formed. It is a manufacturing method.

(Configuration 14)
14. The mask blank manufacturing method according to Configuration 13, wherein the pattern forming thin film is formed of a material containing chromium.
(Configuration 15)
The mask blank according to Configuration 14, wherein the pattern forming thin film is formed of any one of chromium metal, chromium nitride, chromium carbide, chromium carbonitride, and chromium oxycarbonitride. It is a manufacturing method.

(Configuration 16)
An imprint mold manufacturing method using a mask blank manufactured by the mask blank manufacturing method according to any one of Structures 13 to 15, wherein a resist film having a mold pattern formed on the pattern forming thin film is provided. A step of forming a mold pattern on the thin film for pattern formation by dry etching and a thin film for pattern formation on which the mold pattern is formed as a mask and molding in a region where the base structure of the substrate is formed by dry etching. And a process for forming a pattern.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the board | substrate suitable for manufacture of the imprint mold which can be fixed to the fixing jig of a transfer apparatus and can transfer a mold pattern to a transcription | transfer object with a sufficient precision can be provided.
Moreover, according to this invention, the manufacturing method of the mask blank suitable for manufacture of the said imprint mold can be provided using the board | substrate obtained by the manufacturing method of this board | substrate.
Further, according to the present invention, the mask blank obtained by the mask blank manufacturing method is manufactured, fixed to a fixing jig of a transfer device, and the mold pattern can be accurately transferred to the transfer object. A method for producing a print mold can be provided.

It is a cross-sectional schematic diagram for demonstrating the manufacturing process of the board | substrate which concerns on this invention. It is a block diagram which shows 1st Embodiment of the wet etching process which forms the base structure in this invention. It is a block diagram which shows 2nd Embodiment of the wet etching process which forms the base structure in this invention. It is a block diagram which shows 3rd Embodiment of the wet etching process which forms the base structure in this invention. It is a top view of the board | substrate obtained by this invention. It is the cross-sectional schematic for demonstrating other embodiment of the process of forming a recessed part in the one main surface of a board | substrate. (A) thru | or (c) are the cross-sectional schematic diagrams of the mask blank of this invention, respectively. It is a cross-sectional schematic diagram for demonstrating the manufacturing process of the imprint mold which concerns on this invention. It is a cross-sectional schematic diagram for demonstrating the use condition of the imprint mold of this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate.
(Substrate manufacturing method)
First, the manufacturing method of the board | substrate (imprint mold board | substrate) suitable for manufacture of the imprint mold which concerns on this invention is demonstrated.
The substrate manufacturing method according to the present invention includes a step of preparing a substrate having two main surfaces, a step of forming a recess in a recess forming region on one main surface of the substrate, Forming an etching mask film having etching selectivity with respect to the etchant on the pedestal structure forming region on the other main surface of the substrate, and a substrate support for supporting the substrate. The substrate is wet etched by immersing the substrate in the etching solution in a state where the contact portion is brought into contact with the inner surface of the recess and the substrate on which the etching mask film is formed is supported. Forming a pedestal structure in the structure forming region.

FIG. 1 is a schematic cross-sectional view for explaining the manufacturing process of the substrate according to the present invention.
As shown in FIG. 1, the method for manufacturing a substrate according to the present invention includes:
A step of preparing a substrate having two main surfaces (FIG. 1 (a)),
A step of forming a recess in the recess formation region on one main surface of the substrate ((b) in the figure)
A step of forming an etching mask film on the pedestal structure forming region on the other main surface of the substrate (FIGS. (C) to (e)),
In the state where the substrate abutting portion of the support for supporting the substrate is abutted against the inner surface of the recess to support the substrate, wet etching of the substrate is performed, and the pedestal structure is formed in the pedestal structure forming region. Forming step (figure (f), (g)),
It has.
Hereinafter, each step will be described in detail.

First, a substrate 1 having two main surfaces 1A and 1B as shown in FIG.
The substrate 1 applied to the present invention is used as an imprint mold by forming an uneven pattern, which is a mold pattern (mask pattern), on its pattern forming surface (for example, one main surface 1A). Can be arbitrarily used without particular limitation as long as the material has an appropriate strength and rigidity required for use as an imprint mold. Examples thereof include glass materials such as quartz glass, SiO ₂ —TiO ₂ -based low expansion glass, soda lime glass, aluminosilicate glass, and CaF ₂ glass, and silicon. Of these, glass materials are particularly suitable. The glass material can be processed with very high accuracy and is excellent in flatness and smoothness. Therefore, when pattern transfer is performed using the imprint mold obtained by the present invention, distortion of the transfer pattern does not occur. Can perform highly accurate pattern transfer. When the imprint mold manufactured from the substrate 1 is used for a photocurable resin such as an ultraviolet curable resin, it is preferable to form the substrate 1 with a glass material having high light transmittance.

In the present embodiment, the substrate 1 is entirely rectangular in plan view. Of course, the outer shape of the substrate 1 does not need to be limited to such a rectangular shape, and is appropriately determined according to the application, size, etc. of the imprint mold.
Further, the size (size) and the plate thickness of the substrate 1 are not particularly limited, and are appropriately determined according to the use and size of the imprint mold.

Next, the concave portion 7 is formed in the concave portion forming region 8 in one main surface of the substrate 1 (main surface on the 1B side in the present embodiment, hereinafter referred to as “back side main surface”) (FIG. 1 ( b)). The back-side main surface 1B that forms the recess 7 is a surface that is chucked by a mold holding portion of a transfer device that transfers a mold pattern.

Examples of a method for forming the concave portion 7 include machining, but may be appropriately selected according to the size, shape, and depth of the concave portion to be formed and the material of the substrate 1.

The concave portion forming region 8 has, for example, a circular shape in plan view (see FIG. 5). Of course, the shape of the recessed portion forming region 8 (same as the shape of the recessed portion 7 formed in plan view) is not limited to such a circular shape, and may be a rectangular shape or a polygonal shape. It is determined as appropriate according to the use and size.
In addition, when the planar view shape of the recessed part 7 formed is circular, it is desirable that it is a perfect circle shape. The effect of the internal pressure in the space formed by the recess 7 and the transfer device fixing device when the imprint mold is fixed to the transfer device and the transfer device on the deformation of the front main surface is a concentric distribution that is easy to adjust. It is.

Next, an etching mask film is formed on the pedestal structure formation region on the other main surface of the substrate 1 (in this embodiment, the main surface on the 1A side, hereinafter referred to as “front main surface”).
Specifically, the step of forming the etching mask film on the pedestal structure forming region on the front main surface 1A of the substrate 1 is performed by the etching mask film on the front main surface 1A of the substrate 1 as shown in the present embodiment. 2 (see FIG. 1C), a step of forming a resist pattern 3 on a predetermined pedestal structure formation region 4 on the etching mask film 2 (see FIG. 1D), and the resist Preferably, the etching mask film 2 is etched using the pattern 3 as a mask to remove the etching mask film 2 other than the base structure formation region 4 (see FIG. 1E). By performing these steps, an etching mask film pattern 2a is formed on the pedestal structure forming region 4 on the front main surface 1A of the substrate 1 as shown in FIG. The pedestal structure formation region 4 is a region where a mold pattern is formed during the manufacture of an imprint mold using the substrate obtained according to the present invention. The shape of the pedestal structure formation region 4 (that is, the plan view shape of the pedestal structure to be formed) is, for example, a rectangular shape as a whole in the present embodiment (see FIG. 5). Of course, the shape of the pedestal structure formation region 4 is not necessarily limited to such a rectangular shape, and is appropriately determined according to the use, size, and the like of the imprint mold.

The etching mask film 2 (etching mask film pattern 2a) functions as a hard mask layer (etching mask) when wet etching is performed to form a pedestal structure in the pedestal structure formation region 4 of the substrate 1. Therefore, a material having etching selectivity with respect to the substrate 1 is selected for the etching mask film 2 with respect to an etching solution used in wet etching for forming a pedestal structure in a later step. In the present invention, the etching mask film 2 is preferably formed of a material containing chromium, for example. The substrate 1 is preferably made of glass, and an etchant containing hydrofluoric acid is preferably used for wet etching of the substrate 1 in this case.

The chromium-containing material is suitable as a material for the etching mask film 2 because it has good etching selectivity with the substrate 1 made of the glass with respect to an etching solution containing hydrofluoric acid. In addition, when the etching mask film 2 is formed of a material containing chromium, the glass 1 can be formed by either wet etching or dry etching when the etching mask film 2 is removed after the base structure is formed on the substrate 1 made of glass. Since favorable etching selectivity is obtained with respect to the substrate 1 made of

Examples of the material containing chromium (Cr) include Cr alone, or Cr compounds such as Cr nitride, carbide and carbonitride, and CrN is particularly preferable when the etching mask film 2 has a single layer structure. . When the etching mask film 2 has a multilayer structure, the layer on the side in contact with the substrate 1 is preferably formed of chromium nitride. This is because a film made of CrN tends to have high adhesion to the substrate 1. The material made of CrN applied to the etching mask film 2 preferably has a chromium content of 50 atomic% or more.
The material of the etching mask film 2 varies depending on the material of the selected substrate 1 and the composition of the etchant used in the wet etching for forming the pedestal structure, and thus is not limited to the material containing chromium. Absent.

Although the method for forming the etching mask film 2 on the front main surface 1A of the substrate 1 is not particularly limited, for example, a sputtering film forming method is preferable.
Although the film thickness of the etching mask film 2 depends on wet etching conditions (etching depth or etching time) for forming the pedestal structure, it is usually preferably in the range of 50 nm to 200 nm. When the thickness of the etching mask film 2 is less than 50 nm, when the substrate 1 is wet-etched using the etching mask film pattern 2a as a mask, the etching mask film pattern 2a is etched and disappears before the processing is finished. There is a risk that. On the other hand, when the thickness of the etching mask film 2 is greater than 200 nm, the thickness of the resist pattern 3 used as an etching mask when the etching mask film 2 is etched to form the etching mask film pattern 2a is significantly increased. Since it is necessary, it is not preferable.

As a method for forming the resist pattern 3 in the pedestal structure formation region 4 on the etching mask film 2, a photolithography method is suitable. Etching for removing the etching mask film 2 other than the pedestal structure formation region 4 and forming the etching mask film pattern 2a using the resist pattern 3 as a mask is performed using the material of the etching mask film 2 and the etching mask film 2 as follows. Although it depends on the size of the region to be removed, basically, either dry etching or wet etching may be applied.
The resist pattern 3 remaining after the etching may be removed at this stage or may be left as it is. If the resist pattern 3 is left, even if there are pinholes or locally low-density regions in the etching mask film 2, the etching solution used when wet etching the substrate 1 is the pinhole. This is preferable because it can be prevented from contacting the substrate 1 through the substrate and etching the surface of the substrate 1.

  The resist pattern 3 may be formed of either positive type or negative type resist material. The resist pattern 3 may be formed of any resist material for electron beam drawing exposure and laser drawing exposure. Since the resist pattern 3 is a sparse pattern compared to the mold pattern formed in the imprint mold, the resist pattern 3 is a resist for laser drawing exposure that is inferior in resolution to an electron beam drawing exposure resist but is excellent in drawing speed. It is preferable to form the resist pattern 3. The resist pattern 3 may be formed of a photocurable resin or a thermosetting resin.

Next, a process of forming a pedestal structure in the pedestal structure forming region 4 of the substrate 1 will be described.
In the present invention, in this step, the substrate contact portion of the support for supporting the substrate 1 is brought into contact with the inner surface of the concave portion 7 of the back-side main surface 1B of the substrate 1 previously formed. Thus, in a state where the substrate 1 on which the etching mask film pattern 2a is formed is supported by a support, the substrate 1 is immersed in the etching solution and wet etching of the substrate 1 is performed. It is characterized by forming a pedestal structure.

Hereinafter, a specific embodiment of the above process will be described with reference to FIG.
FIG. 2 is a configuration diagram showing a first embodiment of a wet etching process for forming a pedestal structure in the present invention.
As shown in FIG. 2, in the present embodiment, the substrate 1 in which the etching mask film pattern 2 a is formed on the front main surface 1 </ b> A of the substrate 1 in the above-described previous process is supported by the support 52. 1 is immersed in an etching solution 51 accommodated in the treatment tank 50.

In the present embodiment, the support 52 has a structure in which the substrate support 55 is connected to the base 53 by the shaft 54, and the base 53 is installed on the bottom surface of the processing bath 50. The substrate support portion 55 includes a plurality of substrate contact portions 55a on the outer periphery thereof. Each of the plurality of substrate contact portions 55a is configured to contact an inner surface of the recess 7 formed on the back main surface 1B of the substrate 1. In the present embodiment, it is mainly brought into contact with the side wall surface of the recess 7, but it may be further brought into contact with the bottom surface. In order to stably support the substrate 1, the substrate support portion 55 preferably includes at least two or more substrate contact portions 55 a.
The shape (plan view) of the substrate support portion 55 is not particularly limited, but the plurality of substrate contact portions 55a come into contact with the inner surface of the recess 7 to stably support the substrate 1. In order to be able to do so, for example, it is preferable that the shape is the same as the shape of the recess forming region 8.

The material of the support 52 is, for example, resin, but is not particularly limited as long as the material has resistance to the etching solution 51 used in the etching process. In particular, when a liquid containing hydrofluoric acid (hydrofluoric acid) is applied to the etching liquid 51, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), ethylene The support 52 is preferably formed of a fluororesin such as tetrafluoroethylene copolymer, (ETFE), or tetrafluoroethylene-perfluorodioxole copolymer (TFE / PDD).
In the present embodiment, as shown in FIG. 2, the substrate 1 is supported on the substrate support portion 55 of the support 52 with the front main surface 1 </ b> A side facing upward.

As described above, in a state where the substrate abutting portion 55a of the support 52 is brought into contact with the inner surface of the recess 7 formed on the back main surface 1B of the substrate 1 to support the substrate 1, The substrate 1 is immersed in the etching solution 51 and wet etching of the substrate 1 is performed.
As the etching solution 51 in this case, when the substrate 1 is made of glass, an etching solution containing hydrofluoric acid (HF) is preferable. The liquid temperature of the etching solution is set as appropriate. Further, during the etching process, the etching solution may be appropriately stirred as necessary.
The etching time is appropriately determined according to the level difference of the base structure to be formed.

In this way, by performing wet etching of the substrate 1 using the etching mask film pattern 2a formed in the pedestal structure formation region 4 of the substrate 1 as a mask, the substrate 1 is formed in regions other than the pedestal structure formation region 4. The main surface 1A is etched to a predetermined depth, and a pedestal structure 5 is formed in the pedestal structure forming region 4 on the front main surface 1A of the substrate 1 as shown in FIG.

As described above, in the present embodiment (FIG. 2), the step of forming the recess 7 on the back main surface 1B of the substrate 1 is preceded by the step of forming the pedestal structure on the front main surface 1A of the substrate 1. In the wet etching process in which the recess 7 is formed and the pedestal structure 5 is then formed on the main surface 1A on the front side of the substrate 1, the recess 7 of the back main surface 1B of the substrate 1 previously formed is formed. The substrate 1 is supported by the support tool 52 so that the substrate contact portion 55a of the support tool 52 for supporting the substrate 1 is in contact with the inner surface, and the substrate 1 supported by the support tool 52 is supported. Since the wet etching is performed by being immersed in the wet etching solution 51, the end surface of the substrate by performing the wet etching while supporting the substrate with a part of the end surface of the substrate or the main surface in the vicinity of the end surface as in the conventional technique described above. Main surface near end face It does not occur a problem that the step occurs. Therefore, according to the present embodiment, it is easy to ensure the quality of flatness required for the substrate end face for imprint mold.

Note that the finally manufactured imprint mold may have a step formed on the side wall surface or the bottom surface of the recess due to the influence of the wet etching process of the present embodiment. However, it is a level difference (for example, about 30 μm) formed by the wet etching process. In general, the fixing jig of the transfer device does not contact the side wall surface and the bottom surface of the concave portion of the imprint mold. For this reason, when the imprint mold is fixed to the fixing jig, it is not affected by the step formed on the side wall surface or the bottom surface of the recess. For this reason, even if the imprint mold is fixed to the fixing jig of the transfer device and the mold pattern is transferred to the liquid resin, the pattern can be accurately transferred to the cured liquid resin.

FIG. 3 is a block diagram showing a second embodiment of the wet etching process for forming the above-described pedestal structure. In addition, the same code | symbol is attached | subjected to the location equivalent to embodiment shown in above-mentioned FIG. 2, and duplication description is abbreviate | omitted.
Also in the embodiment shown in FIG. 3, the substrate 1 is accommodated in the processing bath 50 in a state where the substrate 1 having the etching mask film pattern 2 a formed on the front main surface 1 </ b> A of the substrate 1 is supported by the support 56. It is immersed in the etching solution 51.

In the present embodiment, the support 56 has a structure in which a substrate support portion 57 is attached to a shaft 58, and the substrate support portion 57 includes a plurality of substrate contact portions 57a on the outer periphery thereof. ing. Each of the plurality of substrate contact portions 57a is configured to contact the inner surface of the recess 7 formed on the back main surface 1B of the substrate 1. In the present embodiment, it is mainly brought into contact with the side wall surface of the recess 7, but it may be further brought into contact with the bottom surface.
In the case of the present embodiment, as shown in FIG. 3, the substrate abutting portion 57 a of the support 56 is the concave portion 7 of the substrate 1 when the substrate 1 is immersed in the etching solution 51 with the main surface 1 A side facing downward. It supports in the state which contact | abutted to the surface inside.

Also in the present embodiment (FIG. 3), the substrate contact portion 57a of the support 56 for supporting the substrate 1 is provided on the back-side main surface during the wet etching step of forming the pedestal structure 5 on the front-side main surface 1A of the substrate 1. The substrate 1 is supported by the support 56 so as to be in contact with the inner surface of the concave portion 7 of 1B, and the substrate 1 supported by the support 56 is immersed in the wet etching solution 51 to perform wet etching. Therefore, there is no problem that a step is generated on the end surface of the substrate or the main surface near the end surface as in the prior art. Therefore, also in the present embodiment, it is easy to ensure the quality of flatness required for the imprint mold substrate end face.

Even in the present embodiment, there is a case where a step is formed on the side wall surface or the bottom surface of the recess due to the influence of the wet etching process, but the level difference is about the level formed by the wet etching process (for example, about 30 μm). It is. Further, as described above, when the imprint mold is fixed to the fixing jig, the imprint mold is not affected by the step formed on the side wall surface or the bottom surface of the recess. For this reason, even if the imprint mold is fixed to the fixing jig of the transfer device and the mold pattern is transferred to the liquid resin, the pattern can be accurately transferred to the cured liquid resin.

FIG. 4 is a block diagram showing a third embodiment of the wet etching process for forming the above-described pedestal structure. In addition, the same code | symbol is attached | subjected to the location equivalent to embodiment shown in above-mentioned FIG.2 and FIG.3, and duplication description is abbreviate | omitted.
In the embodiment shown in FIG. 4, the substrate 1 is accommodated in the processing tank 50 in a state where the substrate 1 having the etching mask film pattern 2a formed on the front main surface 1A of the substrate 1 is supported by the support 60. It is immersed in the etching solution 51.

  In the present embodiment, the support 60 has a substrate support portion 61 attached to a shaft 62, and the substrate support portion 61 includes a substrate contact portion 63 above the substrate support portion 61. The front end of the substrate abutting portion 63 has an adsorption structure (for example, a suction chuck mechanism or a suction cup made of the above-mentioned fluororesin), abuts on the inner bottom surface of the recess 7 of the substrate 1 and Adsorb. In other words, the substrate 1 is supported by the support 60 by the substrate contact portion 63 contacting the bottom surface inside the recess 7 and adsorbing to the bottom surface. Further, the packing member 59 is fitted over the entire periphery of the opening edge of the recess 7, and the outer peripheral edge portion of the substrate support portion 61 is in a state where the substrate contact portion 63 is attracted to the inner bottom surface of the recess 7. Are in close contact so as to push in the packing member 59.

  In the present embodiment (FIG. 4), in addition to the same effects as those of the first and second embodiments described above, the etching solution does not contact the recess 7 of the substrate 1 during the wet etching process. Therefore, it is possible to suppress the formation of steps on the side wall surface and the bottom surface of the recess 7. Further, if there is a latent flaw inside the substrate on the side wall surface or the bottom surface of the concave portion 7 during machining when the concave portion 7 is formed, the etching solution penetrates from the latent flaw and the latent flaw becomes apparent. It can be suppressed.

  After the step of forming the pedestal structure 5 described above, a step of removing the remaining etching mask film pattern 2a can be provided (see FIG. 1G). The method for removing the etching mask film pattern 2a is not particularly limited, but a method that does not damage the material of the substrate 1 is desirable. For example, when the substrate 1 is made of glass and the etching mask film pattern 2a is made of the above-mentioned chromium-based material, wet etching using a mixed solution of ceric ammonium nitrate aqueous solution and perchloric acid as an etching solution, or chlorine-based gas Dry etching using a mixed gas of oxygen gas as an etching gas is preferable.

As described above, the predetermined pedestal structure 5 is formed on the front main surface 1A of the substrate 1.
The above-mentioned recess 7 is formed in a region excluding at least the outer peripheral portion of the back side main surface 1B of the substrate 1, but the recess forming region 8 forming the recess 7 is formed in the front side main surface 1A on the opposite side. It is preferable that the pedestal structure 5 be formed in a larger area than the formation area. That is, the recess forming region 8 is preferably a region having a size including the pedestal structure forming region 4 (see FIG. 5). If the region where the recess 7 is formed is smaller than the region where the pedestal structure 5 is formed, a portion that hardly deforms in the outer mold pattern occurs in the imprint mold, and the resist film sandwiched between the mold pattern that deforms outward is formed. This is because it may be crushed. In particular, in the case of a substrate for producing an imprint mold that performs pattern transfer on a liquid resin such as a photocurable resin, the boundary portion between the concave portion 7 and the back side main surface 1B is a mold having the front side main surface 1A. If the pattern is formed on the pedestal structure forming region, the light for curing the photocurable resin cannot be normally incident, and the resin may be hardened.

In addition, as described above, the region where the recess 7 is formed is preferably a region having a size including the region where the base structure 5 is formed, but considering the rigidity of the substrate 1 on which the recess 7 is formed, When the size of the substrate 1 is about 152 mm square, the diameter of the recess 7 (in the case of a circular shape) or the length in the short side direction (in the case of a rectangular shape) is desirably 100 mm or less, and 90 mm or less. Is preferable.

  As described above, a predetermined base structure 5 is formed on the front-side main surface 1A of the substrate 1 and a substrate (imprint mold substrate) 10 having a recess 7 formed on the back-side main surface 1B is completed (FIG. 1). (See (g)).

  The center of the recess 7 of the imprint mold substrate 10 is most preferably coincident with the center of the substrate 10, and at least the deviation is preferably 100 μm or less, more preferably 50 μm or less. . In general, the center of the mold pattern (uneven pattern) formed in the pedestal structure forming region on the front side main surface is made to coincide with the center of the substrate 10, and the imprint mold on the resist film of the transfer object This is because the deformation at the time of pressing or peeling spreads sequentially from the center of the mold pattern.

  The center of the pedestal structure 5 of the imprint mold substrate 10 is most desirably coincident with the center of the substrate 10, and at least the deviation is preferably 100 μm or less, more preferably 50 μm or less. As described above, the center of the mold pattern (uneven pattern) formed in the pedestal structure forming region on the front main surface is made to coincide with the center of the substrate 10.

A transfer device (stamper device) for transferring a pattern onto an object to be transferred using an imprint mold produced from the imprint mold substrate 10 obtained according to the present invention sandwiches an end surface facing the imprint mold. In the case of the fixing method, it is desirable that the flatness of the imprint mold substrate end face is 20 μm or less, more preferably 10 μm or less. Here, the flatness is a value representing the warpage (deformation amount) of the surface indicated by TIR (Total Indicated Reading). For example, in the (148 mm × 5.0 mm) area of the substrate end surface, the least square method is used with reference to the substrate end surface. The focal plane is defined as the focal plane, and the absolute value of the height difference between the highest position of the substrate end face above the focal plane and the lowest position of the substrate end face below the focal plane.
As described above, the end face of the imprint mold substrate is required to have high flatness, but according to the present invention, it is easy to ensure the quality of flatness required for the imprint mold substrate end face. .

In the above-described embodiment, the case where the concave portion 7 is formed in the concave portion forming region 8 on the back main surface 1B of the single (one) substrate 1 by machining or the like has been described in the present invention. It is not limited.
FIG. 6 is a schematic cross-sectional view for explaining another embodiment of the step of forming a recess in the main surface on the back side of the substrate.
That is, in the step of forming the recess 7 in the recess forming region 8 on the back side main surface 1B of the substrate 1 (FIG. 1B), as shown in FIG. Hole) 6 is bonded to a flat plate-like first base material 1a and at least one flat plate-like second base material 1b, whereby the back main surface 1B of the substrate 1 after bonding. This can be done by forming a recess 7 consisting of the hole 6 of the second base material 1b and the main surface on the bonding side of the first base material 1a in the recess forming region 8.

As the material of the first base material 1a and the second base material 1b constituting the substrate 1, the aforementioned quartz glass, SiO ₂ —TiO ₂ low expansion glass, soda lime glass, aluminosilicate glass, CaF ₂ glass are used. And glass materials such as silicon and the like. Of these, glass materials are particularly suitable. Therefore, it is preferable that the first base material 1a and the second base material 1b constituting the substrate 1 include at least a base material made of glass.

  The first base material 1a and the second base material 1b may be made of the same material or different materials. When different materials are used, it is particularly preferable to combine materials having different thermal expansion coefficients. Since the first base material 1a and the second base material 1b are materials having different thermal expansion coefficients, in addition to forming the recesses 7 in the substrate 1, heating or cooling is performed when the imprint mold is released. Thus, a relative tensile stress or compressive stress acts between the first base material 1a and the second base material 1b, and the mold release becomes easier.

  In the configuration shown in FIG. 6, both the first base material 1a and the second base material 1b use one base material, but one of the first base material and the second base material is used. Alternatively, it is also possible to employ a configuration in which two or more substrates are bonded to each other.

The processing means for drilling the hole 6 having a predetermined shape in the first base material 1a is not particularly limited, and a micromachining method such as a known machining method or etching method is arbitrarily used. be able to. Specifically, for example, a fine processing method such as laser processing, cutting processing, and water jet processing may be appropriately selected in consideration of the material of the base material, the shape and size of the hole to be processed, and the like. .

Next, as means for joining the first base material 1a having the predetermined shape hole 6 and the flat plate-like second base material 1b, the first base material, the second base material, There is no need to be particularly limited as long as the method can obtain a sufficient adhesive strength. Here, the sufficient adhesive force is an adhesive force that does not cause peeling between the first base material and the second base material when the imprint mold is used.
In the present invention, specifically, methods such as a welding (welding) method, an adhesion method, an anodic bonding method, a hydrofluoric acid bonding method, and an optical welding method (optical contact) can be preferably used. What is necessary is just to select and use a suitable joining method suitably according to each material of the 1st base material 1a and the 2nd base material 1b.

  In addition, when joining the said 1st base material 1a and the 2nd base material 1b, even if it uses which joining method as mentioned above, in order to obtain strong joining force, both flat surfaces of both joining surfaces are used. In particular, the optical welding method requires high flatness and high smoothness of the joint surface. Therefore, prior to the step of joining the first base material 1a and the second base material 1b, the joining surfaces of both the first base material 1a and the second base material 1b are respectively set to a predetermined flatness (flatness). The definition of the degree is the same as described above), for example, preferably includes a step of finishing to have a flatness of about 5 μm or less. The processing means for finishing the joint surfaces of the first base material 1a and the second base material 1b so as to have a predetermined flatness is not particularly limited, and is a known machining method. A surface processing method such as an etching method can be arbitrarily used.

According to the method as described above, the holes 6 are formed on the back main surface 1B of the substrate 1 after bonding by bonding at least two substrates including the substrate formed by drilling holes of a predetermined shape. The concave portion 7 can be formed, that is, the concave portion 7 can be formed by previously drilling a hole 6 having a predetermined shape in at least one base material 1 a constituting the substrate 1. Therefore, the processing load of the processing can be reduced, and the concave portion 7 can be accurately formed on the substrate 1 after the bonding. Furthermore, since at least two base materials, ie, the base material 1a in which the holes 6 are previously drilled and the flat base material 1b are joined, the strength and rigidity of the mold can be improved by forming the recesses on one substrate. The risk of decline is reduced.
By forming the pedestal structure 5 in the pedestal structure forming region of the front main surface 1A in the same manner as the method of the embodiment described above for the bonded substrate 1 obtained as described above, The imprint mold substrate 10 can be obtained.

(Manufacturing method of mask blank)
Next, a method for manufacturing a mask blank according to the present invention will be described.
The present invention includes a step of forming a thin film for pattern formation on the main surface of the substrate on which the pedestal structure of the substrate manufactured by the substrate manufacturing method according to the present invention is formed. A manufacturing method is also provided.

(A)-(c) of Drawing 7 is a section schematic diagram of a mask blank obtained by the present invention, respectively.
That is, a mask blank (imprint mold mask blank) 20 shown in FIG. 7A is a front main surface on which the pedestal structure 5 of the mask blank substrate 10 of the present invention is formed, that is, a mold pattern of an imprint mold. The thin film 11 for pattern formation is provided on the surface to be formed (pattern formation surface).
The mask blank substrate 10 has a structure in which the thin film 11 for pattern formation is provided in a part of the region including at least the region where the pedestal structure 5 is formed, instead of the entire front main surface of the mask blank substrate 10 (FIG. 7B) Further, a structure having a thin film for pattern formation only in the base structure formation region (see FIG. 7C) may be used.

The pattern forming thin film 11 has a function as a hard mask film when performing substrate etching (digging) processing for forming a mold pattern in a region where the base structure 5 of the substrate 10 is formed. Therefore, a material having etching selectivity with respect to the substrate 10 is selected for the pattern forming thin film 11 with respect to an etching environment for forming a mold pattern in a later process. In the present invention, the pattern forming thin film 11 is preferably formed of a material containing, for example, chromium. The substrate 10 is preferably made of glass. In this case, for example, fluorine-based gas is used for dry etching of the substrate 10. The material containing chromium has etching selectivity with respect to the fluorine-based gas with respect to the substrate 10 made of the glass.

Examples of the material containing chromium (Cr) include chromium metal, chromium nitride, chromium carbide, chromium carbonitride, and chromium oxycarbonitride. In the case of the pattern forming thin film 11, chromium oxycarbonitride is particularly preferable.

The pattern forming thin film 11 in the mask blank 20 may be a single layer or a plurality of layers. For example, the mask blank which the said thin film 11 consists of a single layer film | membrane of the said chromium-type material is mentioned. Further, for example, a mask blank in which the thin film 11 is composed of a laminated film of at least an upper layer and a lower layer, the upper layer is formed of the chromium-based material, and the lower layer is formed of a material mainly containing tantalum (Ta). In this case, as a material mainly composed of tantalum, for example, Ta compounds such as TaHf, TaZr, TaHfZr, or such Ta compounds as a base material, for example, secondary materials such as B, Ge, Nb, Si, C, N, etc. There are materials with added. In addition, tantalum-based materials are necessary so that it is possible to prevent charge-up during electron beam drawing during resist pattern formation and to inspect substrate patterns (mold patterns) using a scanning electron microscope (SEM). This is preferable because it can have a function of ensuring a good conductivity.
Of course, the configuration and materials of the pattern forming thin film 11 are merely examples, and the present invention is not necessarily limited to these.

The thickness of the pattern forming thin film 11 is not particularly limited, but is preferably in the range of 2 nm to 10 nm, for example. When the film thickness of the thin film 11 is less than 2 nm, when the substrate 10 is etched using the pattern of the thin film 11 as a mask when the mold pattern is manufactured, the pattern of the thin film 11 is etched and disappears before the processing is finished. There is a fear. On the other hand, if the thickness of the thin film 11 is thicker than 10 nm, it is not preferable from the viewpoint of forming a fine pattern. Further, it may be difficult to finally remove the thin film 11 without damaging the material of the substrate 10.

A method for forming the pattern forming thin film 11 on the imprint mold substrate 10 is not particularly limited, but among these, a sputtering film forming method is preferable. The sputtering film forming method is preferable because a uniform film having a constant film thickness can be formed.
Further, the mask blank 20 of the present invention may have a form in which a resist film is formed on the pattern forming thin film 11.

(Imprint mold manufacturing method)
Next, the manufacturing method of the imprint mold concerning this invention is demonstrated.
The present invention also provides a method for producing an imprint mold using the mask blank 20 described above.
That is, the present invention is an imprint mold manufacturing method using the above-described mask blank, wherein the pattern forming thin film is formed by dry etching using a resist film having a mold pattern formed on the pattern forming thin film as a mask. Forming a mold pattern on the substrate, and forming the mold pattern in a region where the base structure of the substrate is formed by dry etching using the pattern forming thin film on which the mold pattern is formed as a mask. It is said.

FIG. 8 is a schematic cross-sectional view for explaining the manufacturing process of the imprint mold according to the present invention.
Hereinafter, the manufacturing process of the imprint mold will be described with reference to FIG.
A liquid photocurable resin (or thermosetting resin) is applied to the upper surface of the mask blank (mask blank for imprint mold) 20 of the present invention (see FIG. 8A). Next, a light irradiation process (or heat treatment) is performed on the above liquid resin while a master mold having a fine pattern is directly pressed to cure the resin, and then the master mold is peeled off. Furthermore, a resist pattern 21a is formed on the pattern forming thin film 11 by performing a descum process for removing the remaining resin film portion by ashing using oxygen plasma or the like (see FIG. 8B).

Next, the mask blank 20 on which the resist pattern 21a is formed is introduced into a dry etching apparatus, and dry etching using an etching gas (for example, chlorine-based gas, Cl ₂ or the like) is performed, thereby masking the resist pattern 21a. As shown in FIGS. 8C and 8D, the pattern forming thin film 11 is etched to form a thin film pattern 11a.
Here, the mask blank may be once taken out from the dry etching apparatus, and the remaining resist pattern 21a may be removed (see FIG. 8D).
Depending on the film configuration and material of the thin film 11, the etching process may be performed in two or more stages instead of one stage.

Next, in the same dry etching apparatus, when the substrate 10 is glass, for example, the substrate 10 is etched using the thin film pattern 11a as a mask by performing dry etching using a fluorine-based gas (CHF ₃ , CF _4, etc.). Then, as shown in FIG. 8E, a mold pattern (uneven pattern) 31 is formed in the region of the substrate 10 where the pedestal structure 5 is formed.

Further, by removing the remaining thin film pattern 11a, an imprint mold 30 in which a mold pattern 31 having a structure as shown in FIG. 8F is formed is obtained. The imprint mold 30 has a structure in which a mold pattern 31 is formed in a region where the pedestal structure 5 is formed on the front side main surface, and a recess 7 is formed on the back side main surface.

FIG. 9 is a schematic cross-sectional view for explaining the usage state of the imprint mold obtained by the present invention.
The imprint mold 30 obtained by the present invention includes a resist film (for example, a photocurable resin or a thermosetting resin) applied on a transfer target constituent layer (for example, a silicon wafer) 41 in a transfer target (transfer target) 40. ) Directly pressed against 42 to transfer the mold pattern 31. By using the imprint mold obtained by the present invention, the mold pattern can be accurately transferred to the transfer object.

As described above in detail, according to the present invention, a substrate suitable for manufacturing an imprint mold that can be fixed to a fixing jig of a transfer device and can accurately transfer a mold pattern to a transfer object is obtained. Can do.
Moreover, according to this invention, the mask blank suitable for manufacture of the said imprint mold can be obtained using the board | substrate obtained by the above.
Furthermore, according to the present invention, an imprint mold that is manufactured using the mask blank obtained as described above, is fixed to a fixing jig of a transfer device, and can accurately transfer a mold pattern to a transfer object is obtained. Can do.

Hereinafter, the present invention will be specifically described by way of examples.
Example 1
An imprint mold substrate used in this example was produced as follows.
A synthetic quartz substrate (size: about 152 mm × 152 mm × thickness (6.35 mm)) was prepared as a glass substrate.
Next, a recess having a predetermined size was formed on the back main surface of the glass substrate by machining. The size of the recess was a perfect circle with a diameter of 64 mm and a depth of 5.2 mm so as to include a later-described pedestal structure region.

Next, the glass substrate on which the recess is formed is placed in a DC sputtering apparatus equipped with a chromium (Cr) target so that the front main surface opposite to the main surface on which the recess is formed is in a positional relationship facing the chromium target. Then, an etching mask film having a structure in which a CrN layer, a CrC layer, and a CrON layer are stacked from the substrate side was formed to a thickness of 105 nm.

Next, a photoresist (THMR-iP3500 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to the top surface of the etching mask film to a thickness of 460 nm, and the outer area of a rectangle (pedestal structure forming region) having a size of 28 mm × 36 mm is applied. Exposure and development with ultraviolet light were performed to form a resist pattern for a pedestal structure.
Next, with respect to the glass substrate on which the resist pattern for the pedestal structure is formed, a resist pattern for the pedestal structure is formed by dry etching using a mixed gas of chlorine gas (Cl ₂ ) and oxygen gas (O ₂ ) as an etching gas. The etching mask film other than the protected part was removed to form an etching mask film pattern for the pedestal structure.

Next, the glass substrate on which the etching mask film pattern was formed was immersed in a predetermined etching solution according to the configuration of the embodiment of FIG. In addition, the support 52 mentioned above used the thing made from resin (PTFE). As an etching solution, a mixed solution of hydrofluoric acid and ammonium fluoride (HF concentration 6 wt%, NH ₄ F concentration 20 wt%) was used, and wet etching was performed on the glass substrate. Further, by removing the remaining resist pattern and etching mask film pattern with a mixed solution of ceric ammonium nitrate aqueous solution and perchloric acid, a pedestal structure having a depth of about 30 μm, for example, was produced.

As described above, the imprint mold substrate of this example was produced.
In addition, as for the position of the center of the said base structure, and the position of the center of the said recessed part, all the deviation | shift with the center position of a glass substrate was all 100 micrometers or less. The flatness of each end face of the substrate was finished to 20 μm or less.

Next, the mask blank was produced using said imprint mold board | substrate.
Reactive sputtering using the imprint mold substrate introduced into a DC sputtering apparatus, using a chromium (Cr) target, and using a mixed gas of argon (Ar), carbon dioxide (CO ₂ ), and nitrogen (N ₂ ) as a sputtering gas. Then, a pattern forming thin film made of a CrOCN film was formed to a thickness of 5 nm on the entire main surface on which the pedestal structure of the imprint mold substrate was formed, thereby preparing a mask blank.

Next, an imprint mold was produced using this mask blank. First, a liquid photocurable resin was applied to the upper surface of the mask blank on which the pattern forming thin film made of the CrOCN film was thus formed. Next, a light irradiation treatment is performed on the above liquid photo-curing resin while a master mold having a line and space with a half pitch of 22 nm is directly pressed to cure the resin, and then the master mold is peeled off. did. Furthermore, a resist pattern was formed on the thin film for pattern formation by performing a descum treatment in which the remaining film portion of the resin was removed by ashing using oxygen plasma or the like.

Next, the mask blank on which the resist pattern is formed is introduced into a dry etching apparatus, and dry etching is performed using a mixed gas of chlorine gas (Cl ₂ ) and oxygen gas (O ₂ ), thereby forming the resist pattern. The pattern forming thin film was etched as a mask to form a thin film pattern. The etching end point at this time was discriminated by using a plasma emission detection type end point detector.
Here, the mask blank was once taken out from the dry etching apparatus, and the remaining resist pattern was removed by oxygen plasma ashing.

Subsequently, by performing dry etching using fluorine-based gas (CHF ₃ ) in the same dry etching apparatus, the glass substrate is etched using the thin film pattern as a mask, thereby obtaining a predetermined mold pattern (uneven pattern). Formed. At this time, the etching time was adjusted so that the depth of the mold pattern was 100 nm.
Here, when a pattern inspection was performed using a scanning electron microscope (SEM), it was confirmed that a good pattern was formed in the width and depth dimensions and accuracy of the mold pattern.

Further, the remaining thin film pattern was removed with a mixed solution of ceric ammonium nitrate aqueous solution and perchloric acid to obtain an imprint mold having a structure as shown in FIG.

Next, the obtained imprint mold is fixed to a transfer device, and as shown in FIG. 9, the resist film (photocurable resin) applied on the silicon wafer in the transfer target (transfer target) is applied. The process of transferring the pattern by direct pressing was repeated, but by using the imprint mold obtained in this example, the mold pattern could be transferred to the transfer object with high accuracy.

(Example 2)
A first substrate 1a (size 152 mm × 152 mm × thickness 5.00 mm) and a second substrate 1b (size 152 mm × 152 mm × thickness) made of synthetic quartz processed into a predetermined shape, size, and plate thickness 1.30 mm) was prepared.
Both of these two base materials 1a and 1b were mirror-polished using a polishing slurry so that both main surfaces had predetermined smoothness and flatness. In particular, the polishing process was performed so that the flatness of the surface to be the bonding surface of each of the substrates 1a and 1b was 5 μm or less. In addition, polishing was performed so that the surface roughness of both main surfaces of the second substrate 1b was 0.3 nm or less in terms of arithmetic average roughness Ra.

After finishing the polishing, the first base 1a was formed by punching a hole having a circular cross section with a diameter of 64 mm centered on the main surface of the base (that is, making a hole).
Next, the first base material 1a and the second base material 1b are joined in a high temperature furnace at 1700 ° C. in a state where the joining surfaces finished to have a flatness of 5 μm or less are overlapped, A glass substrate having a recess made of the hole formed on the back main surface was obtained.

Next, in the same manner as in Example 1, a structure in which a CrN layer, a CrC layer, and a CrON layer are laminated from the substrate side on the front main surface opposite to the main surface on which the concave portion of the second base material 1b is formed. An etching mask film having a thickness of 105 nm was formed. Subsequently, in the same manner as in Example 1, the etching mask film in the outer area of the pedestal structure formation region was removed by dry etching to form an etching mask film pattern for the pedestal structure. Furthermore, the procedure similar to Example 1 was performed, and the imprint mold board | substrate of Example 2 provided with the base structure of about 30 micrometers in the base structure formation area of a front side main surface was manufactured.

In the completed imprint mold substrate of Example 2, the difference between the center position of the pedestal structure and the center position of the recess was 100 μm or less from the center position of the glass substrate. The flatness of each end face of the substrate was finished to 20 μm or less.

Next, the mask blank was produced using said imprint mold board | substrate. That is, in the same manner as in Example 1, a pattern forming thin film made of a CrOCN film was formed to a thickness of 5 nm on the entire main surface on which the pedestal structure for the imprint mold substrate was formed, thereby producing a mask blank. .

Next, using this mask blank, an imprint mold of Example 2 was produced in the same manner as Example 1.
Here, when a pattern inspection was performed using a scanning electron microscope (SEM), it was confirmed that a good pattern was formed in the width and depth dimensions and accuracy of the mold pattern.
Furthermore, an imprint mold was obtained by removing the remaining thin film pattern.

The obtained imprint mold is fixed to the transfer device, and the process of transferring the pattern by directly pressing the resist film (photo-curing resin) applied on the silicon wafer on the transfer target (transfer object) is repeatedly performed. However, by using the imprint mold obtained in this example, the mold pattern could be accurately transferred to the transfer object.
(Comparative Example 1)

In the method of manufacturing the imprint mold substrate of Comparative Example 1, in the step of forming the pedestal structure, the glass substrate is wet in a state of supporting a support tool having a structure that supports a part of the end surface or the main surface near the end surface. The same procedure as in Example 1 was performed except that the etching was performed on the glass substrate. Also, in the mask blank manufacturing method and the imprint mold manufacturing method of Comparative Example 1, the example except that the imprint mold substrate manufactured by the imprint mold substrate manufacturing method of Comparative Example 1 is applied. The same procedure as the manufacturing method of the mask blank of 1 and the manufacturing method of the imprint mold was performed.

As a result, the completed imprint mold substrate is formed with a step of less than 30 μm on the end surface at the same position as the position supported by the support during wet etching when forming the pedestal structure or the main surface near the end surface. It was. For this reason, the flatness of the end face of the imprint mold substrate of Comparative Example 1 was 20 μm or more, and the required flatness could not be satisfied.

In addition, the imprint mold of Comparative Example 1 is fixed to a transfer device, and as shown in FIG. 9 described above, a resist film (for example, a photocurable resin) applied on, for example, a silicon wafer in a transfer target (transfer target). When the step of repeating the process of transferring the pattern by directly pressing to the step), the transfer accuracy deteriorated due to the low flatness of the end face. In addition, due to the fact that a step remains in the vicinity of the end surface of the main surface on the side having the mold pattern, it was already formed on the transfer object during the step-and-repeat transfer to the transfer object. A step near the end face of the imprint mold comes into contact with the resin pattern, and the phenomenon that the resin pattern collapses has also occurred.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Etching mask film 3 Resist pattern 4 Pedestal structure formation region 5 Pedestal structure 6 Hole 7 Recess 8 Recess formation region 10 Substrate (substrate for imprint mold)
11 Pattern Forming Thin Film 20 Mask Blank (Imprint Mask Blank)
21 Resist film 30 Imprint mold 31 Mold pattern 40 Transferred body 41 Transferred body constituting layer 42 Resist film 50 Processing tank 51 Etching solution 52 Supporting tool 53 Base 54 Shaft 55 Substrate support part 56 Support tool 57 Substrate support part 58 Shaft 59 Packing member 60 Support 61 Substrate support portions 55a, 57a, 63 Substrate contact portion

Claims (16)

Providing a substrate with two major surfaces;
Forming a recess in the recess formation region on one main surface of the substrate;
Forming an etching mask film having etching selectivity with respect to the etchant on the pedestal structure forming region on the other main surface of the substrate;
The substrate contact portion of a support for supporting the substrate is brought into contact with the inner surface of the recess to support the substrate on which the etching mask film is formed, and the substrate is immersed in the etching solution. And performing wet etching of the substrate to form a pedestal structure in the pedestal structure formation region,
A method for manufacturing a substrate, comprising:   The support includes a substrate support portion having at least one substrate contact portion, and supports the substrate by bringing the substrate contact portion into contact with an inner side wall surface or a bottom surface of the recess. The method for manufacturing a substrate according to claim 1.   The step of forming the etching mask film on the pedestal structure forming region of the substrate includes a step of forming the etching mask film on the other main surface of the substrate and a resist in the pedestal structure forming region on the etching mask film. 2. The method comprising: forming a film; and performing etching using the resist film as a mask on the etching mask film to remove the etching mask film other than the base structure formation region. Or the manufacturing method of the board | substrate of 2.   4. The method for manufacturing a substrate according to claim 1, further comprising a step of removing the etching mask film after the step of forming the pedestal structure.   5. The method for manufacturing a substrate according to claim 1, wherein the substrate is made of glass, and the etching solution contains hydrofluoric acid.   6. The method for manufacturing a substrate according to claim 1, wherein the etching mask film is formed of a material containing chromium.   The method for manufacturing a substrate according to claim 1, wherein the recess formation region is a region having a size including the pedestal structure formation region.   The substrate according to any one of claims 1 to 7, wherein a position of a center of the substrate is coincident with a position of a center of the recess, or a deviation between positions of the two centers is 100 μm or less. Manufacturing method.   The position of the center of the substrate and the position of the center of the pedestal structure coincide with each other, or the shift between the positions of these two centers is 100 μm or less. A method for manufacturing a substrate.   The step of forming the recess in the recess forming region on one main surface of the substrate includes a flat plate-like first base material having at least one hole having a predetermined shape, and at least one flat plate shape. The method for manufacturing a substrate according to claim 1, wherein a concave portion made of the hole is formed in a concave portion forming region of the substrate after bonding by bonding the second base material. .   The substrate is a substrate used for manufacturing an imprint mold, and the main surface on which the concave portion is formed is a surface that is chucked by a mold holding portion of a transfer device that transfers a mold pattern. The method for manufacturing a substrate according to claim 1, wherein:   The method for manufacturing a substrate according to claim 11, wherein the pedestal structure forming region is a region where a mold pattern is formed during manufacture of an imprint mold.   A mask blank comprising a step of forming a pattern forming thin film on a main surface of the substrate manufactured by the substrate manufacturing method according to claim 1 on which the pedestal structure is formed. Manufacturing method.   The method for manufacturing a mask blank according to claim 13, wherein the pattern forming thin film is formed of a material containing chromium.   15. The mask according to claim 14, wherein the pattern forming thin film is formed of any one of chromium metal, chromium nitride, chromium carbide, chromium carbonitride, and chromium oxycarbonitride. Blank manufacturing method. An imprint mold manufacturing method using the mask blank manufactured by the mask blank manufacturing method according to claim 13,
Forming a mold pattern on the pattern forming thin film by dry etching using a resist film having a mold pattern formed on the pattern forming thin film as a mask;
And a step of forming a mold pattern in a region where the base structure of the substrate is formed by dry etching using the pattern forming thin film on which the mold pattern is formed as a mask.

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