JP2009206339A - Mask blank for imprint molding and method for manufacturing imprint mold - Google Patents

Abstract

An imprint mold mask blank capable of forming a fine glass pattern with high pattern accuracy is provided.
An imprint mold mask blank 10 having a glass substrate 1 and a thin film 2 formed on the substrate, wherein the thin film 2 is made of Ta or Ta compound, or Si or Si compound. It consists of a laminated film of an upper layer 4 made of a material that has a main component and can be etched by a dry etching process using a fluorine-based gas, and a lower layer 3 made of Cr or a Cr compound.
[Selection] Figure 1

Description

  The present invention relates to an imprint mold manufacturing method used for manufacturing an optical component having an optical function added by an integrated circuit such as a semiconductor or a fine pattern, and a mask blank for imprint mold used for the manufacturing.

  In general, in a manufacturing process of a semiconductor device, a fine pattern is formed using a photolithography method. In addition, a number of substrates called photomasks are usually used for forming this fine pattern. This photomask is generally provided with a light-shielding fine pattern made of a metal thin film or the like on a translucent glass substrate, and a photolithography method is also used in the production of this photomask.

  This photomask and imprint mold serve as a master for transferring a large amount of the same fine pattern. The dimensional accuracy of the pattern formed on the photomask directly affects the dimensional accuracy of the fine pattern to be produced. In addition, since the imprint mold is a system in which a pattern is transferred by directly pressing against a resist film coated on a transfer object, the cross-sectional shape of the pattern also greatly affects the shape of the fine pattern to be produced. As the degree of integration of semiconductor circuits improves, the size of the pattern becomes smaller, and higher accuracy of the photomask and imprint mold is required. In particular, the imprint mold is a transfer method that directly presses as described above, and since pattern transfer is performed at the same magnification, the required accuracy is the same as that of a semiconductor circuit pattern. High accuracy is required.

  In the production of a conventional imprint mold, a mask blank in which a thin film such as chromium is formed on a translucent substrate such as quartz glass is used, and after applying a resist on this mask blank, electron beam exposure or the like is used. Then, a resist pattern is formed, and the thin film is etched by using the resist pattern as a mask to form a thin film pattern (mask pattern).

  Further, in an imprint mold used for a transfer object coated with a photocurable resin, a step pattern is produced by etching a translucent substrate using a thin film pattern as a mask for the purpose of irradiating light during transfer. However, also in this case, the pattern size and accuracy of the translucent substrate are directly affected by the size and accuracy of the thin film pattern. Therefore, in order to produce an imprint mold in which a fine pattern with high accuracy is finally formed, it is necessary to form the thin film pattern in the mask blank with high pattern accuracy.

By the way, as a means for etching a thin film containing, for example, chromium, wet etching using cerium nitrate cerium nitrate or dry etching using a mixed gas of chlorine and oxygen is usually used.
Conventionally, a method of forming a thin film pattern composed of a plurality of layers by using multi-stage etching (Patent Document 1 below), or reducing the thickness of a resist, in order to improve the non-uniformity of the etching width and depth of the chromium film. In order to make this possible, a method of forming a thin film pattern using a resist pattern as a mask, and forming a thin film pattern of the second and subsequent layers using the formed thin film pattern as a mask (Patent Document 2 below) is known.

JP-T-2005-530338 JP 2006-78825 A

  As the degree of integration of semiconductor circuits improves, the pattern dimensions are required to be further miniaturized. When the pattern dimensions are miniaturized, for example, when a wet etching method is used, there is a problem in etching the chromium pattern. Is known to occur. That is, in the wet etching using cerium nitrate cerium, there is an advantage that the problem of resist receding and disappearance does not occur so much. On the other hand, the cross-sectional shape of the chromium pattern does not become vertical. There is a problem such as generation of an etching bias that is etched in the lateral direction of the pattern cross section.

  On the other hand, for example, dry etching using a mixed gas of chlorine and oxygen has a problem of resist receding and disappearance, but a vertical chrome pattern cross-sectional shape can be obtained compared to wet etching, so that a fine pattern can be formed. Is advantageous.

  Further, when the pattern dimensions are miniaturized, the resist film thickness is also limited. In other words, if the resist film thickness is approximately three times or more the pattern width, problems such as reduced resolution during resist exposure, pattern collapse after resist pattern formation, and resist stripping occur, so a fine pattern is formed. For this purpose, it is desirable to reduce the resist film thickness. However, for example, when a chromium pattern is formed by dry etching, the resist gradually disappears by etching. Therefore, if the resist film thickness is made too thin, the resist disappears before the completion of the chromium pattern formation, and the chromium portion that should not be etched. As a result, the fine pattern cannot be formed.

  As a method of solving the non-uniformity of the etching width and depth of the chromium film, a method of forming a thin film pattern composed of a plurality of layers using multi-stage etching as disclosed in Patent Document 1 is known. It has been. In this method, the etching stopper improves the non-uniformity of the etching depth, but the method of preventing the resist width from retreating which causes the non-uniformity of the etching width and the thinning of the resist necessary for forming a fine pattern There is no disclosure of a method or the like that makes it possible to solve this problem, and it has not yet fully solved the problems of the prior art in realizing a fine pattern.

  Further, as a method for enabling the thinning of the resist, as disclosed in Patent Document 2, a thin film pattern is formed using the resist pattern as a mask, and the second and subsequent layers are formed using the formed thin film pattern as a mask. A method of forming a thin film pattern is known. In this method, an oxygen-containing chlorine-based gas is used as an etching gas used for etching a thin film with a resist pattern as a mask. However, during dry etching, etching is performed not only in the thickness direction of the resist but also in the lateral direction of the cross section. As the resist pattern advances and recedes, there may be a case where very good pattern accuracy cannot be obtained as a result.

  Further, unlike the case of a general photomask, the problem in manufacturing an imprint mold is not only the formation of the fine pattern as described above. That is, in order to function as an imprint mold for transferring a pattern to a photocurable resin, it is necessary to finally remove a thin film pattern (mask pattern) formed for etching a glass substrate. Therefore, even if a dry (etching) process or a wet process is used to remove such a thin film pattern, it is necessary to remove the thin film pattern so as not to damage the glass pattern after the removal. There is. For that purpose, the thin film material on the glass substrate in the mask blank used for imprint mold production can be easily removed (or peeled off) by wet treatment or dry treatment so as not to damage the glass pattern in the end. It needs to be considered from a viewpoint.

  Therefore, the present invention has been made in view of such conventional circumstances, and the object of the present invention is to firstly form a fine glass pattern with high pattern accuracy in the manufacture of an imprint mold. It is to provide a mask blank for imprint mold, and secondly, to provide a method for manufacturing an imprint mold in which a high-precision fine glass pattern is formed using this mask blank.

That is, in order to solve the above problems, the present invention has the following configuration.
(Configuration 1)
An imprint mold mask blank comprising a glass substrate and a thin film formed on the glass substrate, the imprint mold being produced by etching the thin film and the glass substrate, wherein the thin film Is composed of at least an upper layer and a lower layer laminated film, and the upper layer is mainly composed of either tantalum (Ta) or a tantalum compound, or silicon (Si) or a silicon compound, and a dry etching process using a fluorine-based gas. The imprint mold mask blank is characterized in that the lower layer is formed of chromium (Cr) or a chromium compound.

(Configuration 2)
The upper layer of the thin film is an imprint mold mask blank according to Configuration 1, wherein the upper layer of the thin film is made of a material containing tantalum nitride as a main component.
(Configuration 3)
The upper layer of the thin film is an imprint mold mask blank according to Configuration 1, wherein the upper layer of the thin film is formed of a material mainly composed of a silicon compound of molybdenum (Mo).
(Configuration 4)
4. The imprint mold mask blank according to claim 1, wherein the lower layer of the thin film is formed of chromium nitride.

(Configuration 5)
5. The imprint mold mask blank according to claim 1, wherein the upper layer of the thin film has a thickness in a range of 5 nm to 20 nm.
(Configuration 6)
6. The imprint mold mask blank according to any one of Structures 1 to 5, wherein the resist film formed on the thin film has a thickness of 100 nm or less.

(Configuration 7)
Using the resist pattern formed on the thin film in the imprint mold mask blank according to any one of Structures 1 to 6, the upper layer of the thin film is etched by a dry etching process using a fluorine-based gas, and the upper layer Forming the lower layer pattern by etching the lower layer of the thin film by a dry etching process using a mixed gas of oxygen and chlorine, using the upper layer pattern as a mask, and forming the lower layer pattern And a step of etching the glass substrate by a dry etching process using a fluorine-based gas using the mask as a mask.

As in Configuration 1, the mask blank for imprint mold of the present invention comprises a glass substrate and a thin film formed on the glass substrate, and the imprint is performed by etching the thin film and the glass substrate. An imprint mold mask blank for producing a mold, wherein the thin film comprises at least an upper layer and a lower layer laminated film, and the upper layer is tantalum (Ta) or a tantalum compound, or silicon (Si) or a silicon compound. And a material that can be etched by a dry etching process using a fluorine-based gas (such as CHF ₃ , C ₄ F ₈ , CF _4, or a mixture of any of these and oxygen). The lower layer is formed of chromium (Cr) or a chromium compound.

  According to such an imprint mold mask blank of the present invention, a fine mask pattern can be formed with high pattern accuracy in the manufacture of an imprint mold. Moreover, a highly accurate fine pattern can be formed also about the glass pattern formed by dry etching using the fine mask pattern formed in the said mask blank as an etching mask. Therefore, an imprint mold in which a high-precision fine glass pattern is formed using the mask blank for imprint mold of the present invention can be obtained.

Here, as the glass substrate in the mask blank of the present invention, a glass substrate is generally such as quartz glass or SiO ₂ -TiO ₂ system low-expansion glass. Since these glass substrates are excellent in flatness and smoothness, when pattern transfer is performed using the imprint mold obtained by the present invention, highly accurate pattern transfer can be performed without causing distortion of the transfer pattern.

The mask blank of the present invention is a mask blank for dry etching used for patterning the thin film and the glass substrate on the glass substrate by dry etching to produce an imprint mold.
In order to accurately form a fine pattern, for example, a pattern having a half pitch of less than 32 nm, the resist is thinned, the etching progress in the lateral direction of the resist pattern cross section (resist retreat) is suppressed, and the lateral etching of the thin film pattern cross section is suppressed. Although there is a problem of suppressing the progress (isotropicity of etching), when a thin film pattern is formed by wet etching, the etching progresses in the lateral direction of the thin film pattern cross section, so that a fine pattern is formed. Sometimes dry etching is preferred as in the present invention.

  When forming a thin film pattern by dry etching, there are methods of reducing the resist etching speed and shortening the etching time of the thin film that is patterned using the resist pattern as a mask in order to reduce the resist thickness.

Conventionally, when an imprint mold is manufactured by dry etching a mask blank having a thin film containing chromium as a main component, a mixed gas of chlorine and oxygen is generally used as an etching gas. However, in general, resists have a very low dry etching resistance to an etching gas containing oxygen, which has been a problem. In the present invention, using the resist pattern formed on the mask blank as a mask, the upper layer of the thin film is a fluorine-based gas (such as CHF ₃ , C ₄ F ₈ , CF _4, or a mixed gas of any of these and oxygen). Using the formed upper layer pattern as a mask, the lower layer is etched using a mixed gas of oxygen and chlorine. In dry etching with an etching gas that does not substantially contain oxygen, the etching progress in the vertical and horizontal directions of the resist pattern is smaller compared to dry etching with a chlorine-based gas containing oxygen, and the consumption of the resist in the cross-sectional direction during etching is small. In the present invention, as the dry etching of the upper layer of the thin film in the mask blank, dry etching using an etching gas substantially free of oxygen is possible because the amount of the resist can be suppressed and the dimensional change of the resist can be suppressed. Is preferred. Note that “substantially free of oxygen” means that the content is 5% or less even when oxygen is not contained at all or even when oxygen is generated in the etching apparatus. . Although a chlorine-based gas containing oxygen is used for the lower layer etching, the dimensional change of the resist is not a problem because the upper layer pattern is used as a mask. Therefore, the lower layer pattern can be formed with the same good pattern accuracy as the upper layer pattern.

  In order to shorten the etching time of the thin film on the glass substrate, there are a method of increasing the dry etching rate of the thin film forming the pattern and a method of decreasing the thickness of the thin film forming the pattern. In imprint mold manufacturing, the thin film mainly functions as a hard mask layer (etching mask layer). Therefore, since the thin film needs to have a certain thickness or more, there is a limit to reducing the thickness of the thin film. . Therefore, it is necessary to select a material having a high dry etching rate as a thin film (pattern forming layer). In the mask blank for imprint molds of this invention, the said thin film on a glass substrate consists of a laminated film of an upper layer and a lower layer at least.

  Of the thin film, the upper layer has a function of ensuring adhesion with a resist in addition to a function as a hard mask layer. In the present invention, the upper layer of the thin film is formed of a material mainly composed of Ta or a compound thereof, or silicon or a silicon compound. The upper layer preferably has a high dry etching rate by fluorine-based gas etching and has sufficient resistance to cleaning. From this point of view, the upper layer material specifically includes, for example, Ta compound such as Ta alone or TaX, TaSiX (where X is at least one of N, O, B, Nb, and V), Alternatively, MoSi, Si, SiX, MoSiX (where X is at least one of N, O, B, Nb, and V) are preferable. In particular, Ta nitride (for example, TaN) has a characteristic that it is difficult to oxidize. Further, when B is contained in Ta, an amorphous structure is easily obtained, and the line edge roughness can be reduced.

  The upper layer of the thin film mainly has a function of a hard mask layer, and from the viewpoint of forming a fine pattern, in the present invention, the film thickness is preferably in the range of 5 to 20 nm. When the thickness of the upper layer is less than 5 nm, when the lower layer is etched using the upper layer pattern as a mask, the upper layer pattern may be etched away before the processing is completed, which is not preferable. On the other hand, when the thickness of the upper layer is greater than 20 nm, when the glass substrate described later is dry-etched with a fluorine-based gas, the upper layer film is not fully removed, and the remaining thin film is removed. This is not preferable because it may damage the glass pattern.

  In addition, the lower layer of the thin film functions as a hard mask (etching mask) when the glass substrate is dry-etched using a fluorine-based gas. In the present invention, the lower layer of such a thin film is formed of chromium (Cr) or a Cr compound material. In addition, the lower layer of such a thin film needs to be removed last after the glass substrate is etched to form a glass pattern. For example, the glass pattern is removed without damaging the glass pattern by wet treatment or dry etching treatment. It is important to be able to do it. From such a point of view, in the present invention, the lower layer is formed of chromium (Cr) or a Cr compound. For example, Cr alone or a Cr compound such as CrN, CrC, CrCN, or CrO is preferable. Among these, Cr nitride (for example, CrN), in particular, has an amorphous crystal structure and no crystal grain boundary, so that the etching edge becomes smooth during pattern formation by dry etching. That is, the line edge roughness is reduced and the pattern accuracy can be further improved.

  Of the thin films, the lower layer formed of Cr or a Cr compound material mainly has a function as an etching mask layer, and in the present invention, depending on the digging depth of the glass substrate, The film thickness is preferably in the range of 5 to 20 nm.

  In addition to the function as a hard mask layer, the upper and lower layers of the thin film have sufficient conductivity to prevent charge-up during electron beam drawing during resist pattern formation. It is preferable to have a function to do this. Therefore, it is desirable to select the materials for the upper layer and the lower layer from such a viewpoint.

  In addition, as described above, the upper layer of the thin film needs to ensure adhesion with the resist, but depending on the material of the upper layer as represented by the Si-based material, the adhesion with the resist is low. For example, the surface of the thin film may be treated with an adhesion improver such as HMDS (Hexamethyldisilazane).

  The method for forming a thin film composed of an upper layer and a lower layer on a glass substrate is not particularly limited, but a sputtering film forming method is particularly preferable. The sputtering film forming method is preferable because a uniform film having a constant film thickness can be formed. When a CrN film is formed as a lower layer of the thin film by a sputtering film formation method, a chromium (Cr) target is used as a sputtering target, and a sputtering gas introduced into the chamber is nitrogen gas as an inert gas such as argon gas or helium gas. A gas mixture is used. Further, when a TaN film, for example, is formed as an upper layer of the thin film by a sputtering film formation method, a tantalum target is used as the sputtering target, and the sputtering gas introduced into the chamber is nitrogen gas or inert gas such as argon gas or helium gas. A gas mixture is used.

  Moreover, the mask blank of this invention may be a form which formed the resist film on the said thin film.

  Further, according to the present invention, as in Structure 7, the upper layer of the thin film is etched by a dry etching process using a fluorine-based gas using the resist pattern formed on the thin film in the mask blank of the present invention as a mask. Forming a lower layer pattern by etching the lower layer of the thin film by a dry etching process using a mixed gas of oxygen and chlorine, using the upper layer pattern as a mask, and forming the lower layer pattern And a step of etching the glass substrate by a dry etching process using a fluorine-based gas as a mask.

In the present invention, in the manufacture of the imprint mold, using the resist pattern on the mask blank as a mask as described above, the upper layer of the thin film is dry-etched using a fluorine-based gas to form an upper layer pattern, Subsequently, using the upper layer pattern as a mask, the lower layer of the thin film is dry-etched using a mixed gas of oxygen and chlorine. Therefore, the object of dry etching using the resist pattern formed on the mask blank as a mask is Since only the upper layer of the thin film can be used and the thickness of the upper layer of the thin film can be optimized from the viewpoint of fine pattern formation, even if the thickness of the resist film is made thinner than before, the resist film thickness does not become insufficient. A pattern can be formed.
In addition, since the upper layer is simultaneously etched away with a fluorine-based etching gas when digging glass, the thin film after completion of digging can be peeled off without adversely affecting the glass pattern.

  In the present invention, for example, from the viewpoint of forming a fine pattern with a half pitch of less than 32 nm, the film thickness of the resist film formed on the thin film can be made 100 nm or less, particularly in the range of 40 to 80 nm. Is preferred.

ADVANTAGE OF THE INVENTION According to this invention, the mask blank for imprint molds which can form a fine glass pattern with high pattern precision in manufacture of an imprint mold can be provided.
Moreover, according to this invention, the manufacturing method of the imprint mold in which the highly accurate fine glass pattern was formed using this mask blank can be provided.

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view of an imprint mold mask blank according to the present embodiment, and FIG. 2 is a schematic cross-sectional view for explaining an imprint mold manufacturing process using the mask blank.
As shown in FIG. 1, an imprint mold mask blank (hereinafter simply referred to as a mask blank) 10 used in the present embodiment is a thin film 2 made of a laminated film of an upper layer 4 and a lower layer 3 on a glass substrate 1. It is the structure of having. The mask blank 10 is manufactured as follows.

A synthetic quartz substrate (size 152 mm × 152 mm × thickness 6.35 mm) is introduced as a glass substrate 1 into a sputtering apparatus, and a chromium target is sputtered with a mixed gas of argon and nitrogen (mixing flow rate ratio 9: 1), and CrN (Cr : N = 9: 1 atomic ratio) The lower layer 3 made of a film was formed with a thickness of 10 nm. Subsequently, the tantalum (Ta) target is sputtered with a mixed gas of argon and nitrogen (mixing flow rate ratio 3: 2) without leaving in the atmosphere, and the upper layer 4 made of a TaN (Ta: N = 7: 3 atomic ratio) film is formed. Was formed to a thickness of 10 nm.
An electron beam drawing resist (ZEP520A manufactured by Nippon Zeon Co., Ltd.) is applied to a thickness of 50 nm on the upper surface of the mask blank in which the laminated film of the CrN film and the TaN film is formed on the quartz substrate in this manner, and a predetermined baking process is performed. A resist film was formed on the mask blank 10.

  Next, a line and space pattern having a half pitch of 20 nm was drawn on the resist film of the mask blank 10 using an electron beam drawing machine, and then the resist film was developed to form a resist pattern 6 (FIG. 2A). reference).

Next, the mask blank 10 on which the resist pattern 6 is formed is introduced into a dry etching apparatus, and dry etching using a fluorine-based (CHF ₃ ) gas is performed, whereby the TaN film of the upper layer 4 using the resist pattern 6 as a mask. Was etched to form a TaN film (upper layer 4) pattern (upper layer pattern 7) as shown in FIG. 2 (b). The etching end point at this time was determined by using a reflection optical end point detector.
Here, the mask blank was once taken out from the dry etching apparatus, and the remaining resist pattern 6 was removed with an aqueous sulfuric acid solution (see FIG. 2C).

Next, the mask blank is again introduced into the same dry etching apparatus, and dry etching is performed using a mixed gas of oxygen and chlorine (O ₂ : Cl ₂ = 2: 8 flow ratio), thereby using the upper layer pattern 7 as a mask. The CrN film of the lower layer 3 was etched to form a pattern (lower layer pattern 8) of the CrN film (lower layer 3) as shown in FIG. The etching end point at this time was determined by using a reflection optical end point detector.

Subsequently, by performing dry etching using a fluorine-based (CHF ₃ ) gas in the same dry etching apparatus, the glass substrate 1 is etched using the CrN film pattern 8 of the lower layer 3 as a mask. A glass pattern 9 shown in (e) was formed. At this time, the etching time was adjusted so that the depth of the glass pattern 9 was 70 nm. The TaN film pattern of the upper layer 4 was simultaneously etched by dry etching using this fluorine-based gas.

  Here, in order to confirm the cross-sectional shape of the pattern, the evaluation blank produced in the same manner as above was broken and the cross-section of the pattern was observed with a scanning electron microscope. As a result, the TaN film pattern disappeared and the CrN film pattern 8 The surface of was exposed. And it confirmed that the width | variety of the glass pattern 9 was almost the same as the width | variety of the said CrN film | membrane pattern 8, and the depth of the glass pattern 9 was uniform.

  Next, a photoresist (iP3500, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied to a thickness of 460 nm on the mask blank on which the glass pattern 9 is formed, and exposure and development with ultraviolet light are performed, and the pedestal structure shown in FIG. A resist pattern 11 was formed.

Next, the CrN film other than the portion protected by the resist pattern 11 is removed from the mask blank on which the resist pattern 11 is formed by wet etching with a ceric ammonium nitrate solution, and hydrofluoric acid and ammonium fluoride are removed. 2 (g) is obtained by performing wet etching on the glass substrate with a mixed solution (HF concentration: 4.6 wt%, NH ₄ F concentration: 36.4 wt%) and removing the resist pattern 11 with sulfuric acid / hydrogen peroxide. Thus, a base structure 12 having a depth of, for example, about 15 μm was produced. Further, the CrN film pattern 8 was removed with a ceric ammonium nitrate solution to obtain an imprint mold 20 having a structure shown in FIG.

  The obtained imprint mold 20 was good because both the upper layer pattern 7 and the lower layer pattern 8 of the thin film had a vertical cross-sectional shape, and the pattern accuracy of these patterns was also good. A pattern with good dimensions and accuracy was obtained.

In the present embodiment, the CrN film pattern 8 is finally removed by wet processing, but may be removed by dry etching using, for example, chlorine gas.
In the present embodiment, the TaN is used as the upper layer 4. However, instead of TaN, Ta compounds such as TaB, TaGe, TaNb, and TaV and their oxides, nitrides, oxynitrides, and the like are used. Tantalum silicide (TaSi), TaSiO, TaSiN, TaSiON, or the like, or molybdenum silicide (MoSi), MoSiO, MoSiN, MoSiON, or the like can be used. Further, as the lower layer 3, for example, CrC, CrO, CrCN, CrOCN or the like may be used instead of CrN.

  In the above-described embodiment, the upper TaN film is etched using the resist pattern 6 formed on the mask blank 10 as a mask to form the TaN film (upper layer 4) pattern 7, and then the remaining resist pattern. 6 is removed (step of FIG. 2 (c)), but without removing the resist pattern 6, the lower CrN film is etched using the upper layer pattern 7 as a mask to obtain a CrN film (lower layer). The pattern 8 of 3) is formed. Thereafter, the remaining resist pattern 6 and upper TaN film pattern 7 may be removed by dry etching using, for example, chlorine gas. In this case, the glass substrate is subsequently etched using the lower CrN film pattern as a mask.

  In another embodiment, the upper TaN film is etched using the resist pattern 6 formed on the mask blank 10 as a mask to form a TaN film (upper layer 4) pattern 7, and then the upper layer is formed. The lower CrN film is etched using the pattern 7 as a mask to form a pattern 8 of the CrN film (lower layer 3). Subsequently, the glass substrate is dry-etched using a fluorine-based gas using the lower layer pattern 8 as a mask. At the same time, the remaining resist pattern 6 and the upper TaN film pattern 7 may be removed by fluorine-based gas etching.

It is the cross-sectional schematic of the mask blank for imprint molds of this invention. It is a cross-sectional schematic diagram for demonstrating the manufacturing process of the imprint mold of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Thin film 3 Lower layer 4 Upper layer 6 Resist pattern 7 Upper layer pattern 8 Lower layer pattern 9 Glass pattern 10 Mask blank 11 for imprint molds Resist pattern 12 Base structure 20 Imprint mold

Claims (7)

1. An imprint mold mask blank for producing an imprint mold by etching a thin film and the glass substrate, comprising a glass substrate and a thin film formed on the glass substrate,
   The thin film comprises at least an upper layer and a lower layer laminated film,
   The upper layer is formed of a material that has tantalum (Ta) or a tantalum compound, or silicon (Si) or a silicon compound as a main component, and can be etched by a dry etching process using a fluorine-based gas.
   The imprint mold mask blank, wherein the lower layer is made of chromium (Cr) or a chromium compound.
2.   2. The imprint mold mask blank according to claim 1, wherein the upper layer of the thin film is made of a material mainly composed of tantalum nitride.
3.   2. The mask blank for imprint mold according to claim 1, wherein the upper layer of the thin film is formed of a material mainly composed of a silicon compound of molybdenum (Mo).
4.   4. The imprint mold mask blank according to claim 1, wherein the lower layer of the thin film is formed of chromium nitride.
5.   5. The imprint mold mask blank according to claim 1, wherein a film thickness of an upper layer of the thin film is in a range of 5 nm to 20 nm.
6.   6. The imprint mold mask blank according to claim 1, wherein a film thickness of the resist film formed on the thin film is 100 nm or less.
7.   The upper layer of the thin film is etched by a dry etching process using a fluorine-based gas using the resist pattern formed on the thin film in the mask blank for imprint mold according to any one of claims 1 to 6 as a mask. A step of forming an upper layer pattern; a step of etching the lower layer of the thin film by a dry etching process using a mixed gas of oxygen and chlorine using the upper layer pattern as a mask; and forming the lower layer pattern; And a step of etching the glass substrate by a dry etching process using a fluorine-based gas using a pattern as a mask.

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