JP6357753B2 - Manufacturing method of nanoimprint mold - Google Patents

Description

  The present invention relates to a nanoimprint mold used in a nanoimprint method for forming a fine uneven pattern and a manufacturing method thereof, and more particularly, when an uneven mask pattern that can be an etching mask is formed on a substrate, the uneven mask. The present invention relates to a method of manufacturing a nanoimprint mold capable of obtaining a nanoimprint mold having a concavo-convex portion composed of a single material finally corrected in size by correcting the dimension of the pattern.

  In recent years, especially in semiconductor devices, high speed operation and low power consumption operation have been required due to further progress in miniaturization. Further, a high technology such as integration of functions called a system LSI has been demanded.

  Under such circumstances, the lithography technology, which is the key to producing semiconductor device patterns, has pointed out the limitations of the photolithography method due to the problem of exposure wavelength as device pattern miniaturization progresses.・ The nanoimprint method is attracting attention as a fine patterning method.

  In the nanoimprint method, a nanoimprint mold (template) with a nanometer-size uneven pattern formed in advance on the surface is pressed against a transfer material such as resin applied to the surface of the substrate to be processed, and the transfer material is mechanically deformed to generate unevenness. This is a technology for transferring patterns precisely. Then, for example, by using a patterned transfer material as a resist mask, the substrate to be processed can be finely processed.

  In such a nanoimprint method, once a nanoimprint mold is prepared, the same nanostructure can be easily and repeatedly formed. Therefore, high throughput can be obtained and it is economical, and nanoprocessing with less harmful waste Since it is a technology, in recent years it has been applied to various fields, not limited to semiconductor devices.

  By the way, in the nanoimprint method, it is required to improve the dimensional accuracy of the nanoimprint mold concavo-convex pattern to be used, and it may be required to correct the dimension of the concavo-convex pattern. In addition, it is desirable to change the uneven pattern dimensions of the nanoimprint mold in response to variations in the characteristics of various processing steps within the plane of the substrate when the pattern is transferred (for example, variations in processing conditions and variations in materials used). There is also a case.

  In order to meet such a demand, for example, in Japanese Patent Application Laid-Open No. 2011-108920 (Patent Document 1), a concavo-convex pattern is formed on the main surface of the mold, and the concavo-convex pattern is made of the same material as the nanoimprint mold. There has been disclosed a technique for correcting the size of the concavo-convex pattern formed on the main surface of the mold by forming an atomic deposition layer and adjusting the formation thickness of the atomic deposition layer.

JP 2011-108920 A

  However, in the configuration of Patent Document 1 described above, an atomic deposition layer having a predetermined thickness is deposited on the concavo-convex pattern formed on the nanoimprint mold body to adjust the dimension of the concavo-convex pattern, which is the main part of the mold, to correct the size. It is configured to do. Although such an atomic deposition layer for correction purposes is made of the same material as the nanoimprint mold, the molecular structure and crystal structure are different, and the concave and convex portions that are the most important parts of the mold are not homogeneous and have sufficient durability. It's hard to say.

  The present invention has been devised under such circumstances, and its purpose is to determine the dimensions of the concave / convex mask pattern when a concave / convex mask pattern that can serve as an etching mask is formed on a substrate. An object of the present invention is to provide a nanoimprint mold manufacturing method capable of correcting the unevenness dimension of a mold to be finally formed by correction, and a nanoimprint mold having unevenness portions formed homogeneously from a single material.

In order to solve the above-described problems, a method for producing a nanoimprint mold of the present invention includes a resin as a main component on an intermediate film on the first main surface portion of a substrate having a first main surface portion formed of a plane. A basic mask pattern forming step of patterning a convex basic mask portion, which is a resist, and a convex base so as to cover a side surface and an upper surface of the convex basic mask portion and an upper surface of the intermediate film A dimension correcting film part forming step for forming a dimension correcting film part for correcting the dimension of the mask part, and an etch back for exposing the upper surface of the intermediate film by etching back the dimension correcting film part; An intermediate film etching step of etching the intermediate film using an etching mask patterned on the intermediate film by the etch back process, and the intermediate film etching step. And a substrate etching step of etching the first main surface portion of the substrate using an intermediate film mask patterned on the first main surface portion of the substrate by a chucking step, and the dimension correcting film In the portion forming step, ALD is performed at a temperature _TL lower than the glass transition temperature Tg of the resist constituting the convex base mask portion on the side and top surfaces of the convex basic mask portion and the upper surface of the intermediate film. Law (atomic layer deposition) by depositing a first layer of atomic layers, and facilities annealed to atomic layer of the first layer at the temperature T _L is higher than the temperature T _H1, higher than the temperature T _L The second and subsequent atomic layers are sequentially deposited by an ALD method (atomic layer deposition method) at a temperature T _H2 , thereby forming the dimension correcting film portion composed of a plurality of atomic layers. Is done.

Moreover, the manufacturing method of the nanoimprint mold of the present invention has a convex shape, which is a resist mainly composed of a resin, on an intermediate film on the first main surface portion of the substrate having the first main surface portion formed of a plane. A first mask pattern forming step for patterning the first mask portion; and a first film portion for depositing the first film portion so as to cover a side surface and an upper surface of the convex first mask portion and an upper surface of the intermediate film A film portion forming step; and etching back the first film portion to expose an upper surface of the first mask portion and an upper surface of the intermediate film, and the first film portion is a side surface of the first mask portion. Etching back process to be formed as side wall convex portions, and the first mask portion is removed to form the side wall convex portions on the first main surface portion of the substrate via the intermediate film. Convex base mask A basic mask pattern forming step for forming a pattern, and a dimension correction for correcting the dimension of the convex basic mask portion so as to cover the side surface and the upper surface of the convex basic mask portion and the upper surface of the intermediate film A film portion forming step for forming the film portion, an etch back step of etching back the film portion for dimension correction to expose the upper surface of the intermediate film, and an etching back step of the intermediate film. An intermediate film etching step for etching the intermediate film using an etching mask patterned thereon, and an intermediate film mask patterned on the first main surface portion of the substrate by the intermediate film etching step utilizing, and a substrate etching step of etching the first main surface of the substrate, in the basic mask pattern forming step, the After removing one mask portion, annealing is performed on the side wall convex portion at 200 to 800 ° C., thereby pattern-forming a convex basic mask portion composed of the side wall convex portion, and the dimension correcting film portion In the forming step, a first atomic layer is deposited by ALD (atomic layer deposition method) at a predetermined temperature on a side surface and an upper surface of the convex basic mask portion and an upper surface of the intermediate film, and facilities annealed to atomic layer of the first layer at a temperature higher than the temperature, the predetermined ALD process at a temperature higher than the temperature (atomic layer deposition) by sequentially depositing the second layer and subsequent atomic layer Thus, the dimension correcting film portion constituted by a plurality of atomic layers is formed.

In the method for producing a nanoimprint mold of the present invention, a basic mask material layer made of an inorganic material is formed on the first main surface portion of the substrate having the first main surface portion formed of a plane via an intermediate film. A first mask pattern forming step of patterning a convex first mask portion on the basic mask material layer, etching the basic mask material layer using the first mask portion as an etching mask, and the first mask A basic mask pattern forming step of patterning a convex basic mask portion on the intermediate film, and covering the side surface and the upper surface of the convex basic mask portion and the upper surface of the intermediate film by removing the portion In addition, a dimension correcting film part forming step for forming a dimension correcting film part for correcting the dimension of the convex base mask part, and etching back the dimension correcting film part are performed. An etch back process for exposing an upper surface of the intermediate film; an intermediate film etching process for etching the intermediate film using an etching mask patterned on the intermediate film by the etch back process; A substrate etching step of etching the first main surface portion of the substrate by using an intermediate film mask patterned on the first main surface portion of the substrate by an intermediate film etching step, In the correction film portion forming step, a first atomic layer is deposited on the side surface and upper surface of the convex base mask portion and the upper surface of the intermediate film by an ALD method (atomic layer deposition method) at a predetermined temperature. and facilities annealed to said first layer of atomic layer at a temperature higher than the predetermined temperature, the ALD method (atomic layer deposition) at a temperature higher than the predetermined temperature By successively depositing two layers subsequent atomic layer, configured to form a film portion for the dimension correction made from the atomic layer of the multiple layers.

In a preferable embodiment of the production method of a nanoimprint mold according to the present invention, methods of forming a pre Kimoto foundation mask pattern forming the convex basic mask portion in the process, an electron beam (EB) lithography, photolithography, or Consists of nanoimprint method.

In a preferable embodiment of the production method of a nanoimprint mold according to the present invention, method of forming the first mask part of the convex in the first mask pattern forming step, an electron beam (EB) lithography, photolithography, or Consists of nanoimprint method.

In a preferable embodiment of the production method of a nanoimprint mold according to the invention, a technique first mask portion of the convex is composed of the resist, thereby forming a first mask portion of the convex in the first mask pattern forming step The electron beam (EB) lithography method, the optical lithography method, or the imprint method.

  The method for producing a nanoimprint mold of the present invention includes a basic mask pattern forming step of patterning a convex basic mask portion on a substrate via an intermediate film, and a convex basic mask for the convex basic mask portion. A dimension correcting film part forming step for forming a dimension correcting film part for correcting the dimension of the part, so that the uneven dimension of the mold to be finally formed can be corrected. Moreover, since the said uneven | corrugated | grooved part consists of a single material and can be comprised uniformly, the durability of a mold becomes very excellent.

  In addition, the nanoimprint mold of the present invention has uneven portions that are homogeneously formed of a single material, and has excellent durability.

Drawing 1 (A)-(D) is a sectional view for explaining the example of a process of a 1st embodiment in a manufacturing method of a nano imprint mold of the present invention over time. FIGS. 2A to 2C are cross-sectional views for explaining the process example of the first embodiment in the nanoimprint mold manufacturing method of the present invention over time, following the process of FIG. It is a drawing. FIGS. 3A to 3D are cross-sectional views for explaining the process example of the second embodiment in the nanoimprint mold manufacturing method of the present invention over time. FIGS. 4A to 4C are cross-sectional views for explaining a process example of the second embodiment in the nanoimprint mold manufacturing method of the present invention over time, following the process of FIG. It is a drawing. FIGS. 5A to 5C are cross-sectional views for explaining a process example of the second embodiment in the nanoimprint mold manufacturing method of the present invention over time, following the process of FIG. It is a drawing. FIG. 6 is a plan view for explaining a process example of the method for producing a nanoimprint mold of the present invention, and corresponds to a plan view at the time of the process shown in FIG. 4 (B). FIG. 7 is a plan view showing a state after removing both ends in the longitudinal direction of the closed loop pattern in the plan view shown in FIG. FIG. 8 is a perspective view drawn so that the state of the closed loop pattern can be easily understood, and corresponds to a part of the perspective view at the time of the step shown in FIG. FIGS. 9A to 9D are cross-sectional views illustrating the process example of the third embodiment in the nanoimprint mold manufacturing method of the present invention over time. FIGS. 10A to 10D are cross-sectional views for explaining a process example of the third embodiment in the nanoimprint mold manufacturing method of the present invention over time, and are subsequent to the process of FIG. 9D. It is a drawing.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the form demonstrated below, In the range which does not deviate from a technical thought, it can implement in various deformation | transformation. In the accompanying drawings, the vertical and horizontal scales may be exaggerated for the sake of explanation, and the actual scales may differ.

  First, a first embodiment of a method for producing a nanoimprint mold of the present invention will be described with reference to FIGS.

  <Method for Producing Nanoimprint Mold (First Embodiment)>

  FIGS. 1A to 1D are cross-sectional views for explaining the process example of the first embodiment in the nanoimprint mold manufacturing method of the present invention over time, and FIGS. These are sectional drawings for demonstrating the process example of 1st Embodiment in the manufacturing method of the nanoimprint mold of this invention over time, and are drawings following the process of FIG.1 (D).

  The manufacturing method of the nanoimprint mold of the present invention in the first embodiment includes a basic mask pattern forming step of forming a convex basic mask portion on a substrate via an intermediate film as a main part thereof, and the basics A dimension correcting film part forming step of forming a dimension correcting film part for correcting the dimension of the mask part on the mask part.

  Further, the manufacturing method of the nanoimprint mold in the first embodiment will be described in detail. The manufacturing method includes (1) a step of preparing a substrate having a first main surface portion composed of a plane, and (2) the first main surface portion of the substrate. Above, a basic mask pattern forming step for patterning a convex basic mask portion through an intermediate film, and (3) dimensional correction so as to cover the side surface and upper surface of the convex basic mask portion and the upper surface of the intermediate film A dimension correcting film part forming step for forming a film part for etching, (4) an etch back process for etching back the dimension correcting film part to expose the upper surface of the intermediate film, and (5) an etch back process. An intermediate film etching step of etching the intermediate film using an etching mask patterned on the intermediate film; and (6) the first main surface portion of the substrate by the intermediate film etching step. By using the intermediate film mask which is turn formed, and a first main surface of the substrate comprises a substrate etching step of etching, the.

Hereinafter, each step will be sequentially described.
(1) The process of preparing the board | substrate which has the 1st main surface part which consists of a plane.

  As shown in FIG. 1A, a substrate 10 for a nanoimprint mold is prepared. A first main surface portion 11a is formed on one main surface 11 of the substrate 10 thus prepared, and an intermediate film 20 is formed on the first main surface portion 11a.

  On the intermediate film 20, a convex basic mask portion described later is formed.

  In FIG. 1A, an example is shown in which the entire area of the principal surface 11 on one side of the substrate 10 constitutes a first principal surface portion 11a composed of a plane. However, the configuration is not limited to the illustrated configuration. For example, the substrate 10 having a so-called mesa structure in which only the area in which the intermediate film 20 and a convex basic mask portion described later are provided partially constitutes a first main surface portion that is a flat surface. The mesa structure is not limited to one stage and may be multistage.

  The material of the substrate 10 can be appropriately selected. For example, when the nanoimprint mold is used as a so-called mold for optical imprinting, the substrate 10 is formed using a transparent base material that can transmit irradiation light. Further, glass such as quartz glass, silicate glass, calcium fluoride, magnesium fluoride, and acrylic glass, resin such as polycarbonate, polypropylene, and polyethylene, or any laminated material thereof can be used. For example, when the nanoimprint mold is used as a so-called thermal imprint mold, the substrate 10 does not necessarily need to be a transparent base material, for example, a metal such as nickel, titanium, or aluminum, or a semiconductor such as silicon or gallium nitride. May be used.

  The thickness of the substrate 10 serving as the base of the nanoimprint mold can be set in consideration of the strength of the substrate, the handleability, and the like, and can be set as appropriate within a range of about 300 μm to 10 mm, for example.

  As the intermediate film 20 provided on the substrate 10, a material having an etching rate smaller than that of the substrate 10 and having etching resistance can be used. For example, a metal such as chromium, titanium, tantalum, silicon, and aluminum, nitride Chrome compounds such as chromium, chromium oxide, chromium oxynitride, tantalum oxide, tantalum oxynitride, tantalum boride, tantalum compounds such as tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride, etc. Or it can be used in combination of 2 or more types. The film thickness is usually 50 nm or less, particularly 1 to 20 nm, more preferably about 3 to 10 nm.

  The intermediate film 20 can be formed by, for example, sputtering, vapor deposition, ion plate, or the like.

The intermediate film 20 may be configured as a laminated film having two or more layers.
(2) Basic mask pattern formation process

  Next, as shown in FIG. 1B, a basic mask for forming a convex basic mask portion 30 in a predetermined pattern on the intermediate film 20 formed on the first main surface portion 11a of the substrate 10. A pattern forming process is performed. The “basic mask portion” as used in the present invention means a mask that is a base that is directly attached to a dimensional correction by directly attaching a film portion for dimensional correction.

  In the first embodiment, the convex basic mask portion 30 is preferably composed of a so-called resist mainly composed of a resin, and is convex by, for example, an electron beam (EB) lithography method, a photolithographic method, or a nanoimprint method. The basic mask portion 30 can be patterned.

  When the electron beam (EB) lithography method is used as a first technique, a resist forming step of forming an electron beam sensitive resin film on the intermediate film 20 of the substrate 10 is performed, and then the formed electron beam sensitive Electron beam drawing is performed on the conductive resin film so as to form a desired pattern.

  After the electron beam drawing is completed, a resist developing process for developing the electron beam sensitive resin film is performed. For example, when a positive type electron beam sensitive resin film is used, the unexposed portion remains as a resist without being decomposed, and a convex basic mask portion 30 is formed in a predetermined pattern (negative type electron beam sensitive resin film). When the conductive resin film is used, the irradiated portion remains as a resist without being decomposed, and a pattern opposite to the positive type is formed).

  As a second method, when the photolithography method is used, a resist forming step for forming a photosensitive resin film is performed on the intermediate film 20 of the substrate 10, and then the desired photosensitive resin film is applied to the desired photosensitive resin film. The exposure operation is performed through the mask pattern so as to form the pattern. After the exposure operation is completed, a resist development process for developing the photosensitive resin film is performed. For example, when a positive photosensitive resin film is used, the unexposed portion remains as a resist without being decomposed, and a convex basic mask portion 30 is formed in a predetermined pattern (a negative photosensitive resin film is formed). When used, the exposed portion remains as a resist without being decomposed, and a pattern opposite to the positive type is formed).

  As a third method, when the nanoimprint method is used, for example, a photocurable resin material is supplied and disposed as an object to be transferred on the intermediate film 20 of the substrate 10 by a dispenser, an inkjet, or the like. Next, a mold having a desired concavo-convex structure is brought into contact with the disposed resin material, and pressure is applied as necessary (so-called mold pressing step). In this state, the resin material becomes a resin layer having an uneven structure, and the resin material is cured by irradiating the resin layer with ultraviolet rays (so-called resin curing step). Next, by separating the mold from the resin material, a convex basic mask portion 30 in which the concave-convex structure of the mold is inverted is formed on the intermediate film 20 of the substrate 10 in a predetermined pattern. The so-called residual film can be removed by oxygen ashing or the like.

  The convex basic mask portion 30 referred to in the first embodiment is a so-called resist, and is a structure including a resin material as a main component. As another method, a hard mask having a two-layer structure made of different materials is used, and an upper layer hard mask is formed into a predetermined pattern using the above-described various pattern forming methods. It is also possible to configure the upper hard mask as a convex basic mask portion.

  Moreover, the pattern form of the convex basic mask part 30 is, for example, a so-called line and space form in which the concavo-convex shape extends in a row in the longitudinal direction, a form in which the dot shape is dispersed in a predetermined pattern, Any of a form in which hole shapes are dispersed in a predetermined pattern, a form in which these individual shapes are combined, a special three-dimensional structure other than these, and the like may be used. In this specification, the master nanoimprint mold is simply referred to as “master mold”, and nanoimprint molds manufactured using the master mold may be collectively referred to as “replica molds”.

  Among the methods for forming the three convex basic mask portions 30, the case of forming the convex basic mask portion 30 shown in FIG. 1B by using the nanoimprint method is particularly the present invention. It is possible to effectively express the effects of the above. That is, in the imprint technique, when a master mold for forming the convex basic mask portion 30 shown in FIG. For example, it is impossible to correct the uneven dimensions of the replica mold formed by one reversing operation. However, since the present invention includes the dimension correcting film portion forming step described later, the uneven dimension of the replica mold formed from the master mold can be corrected. That is, even if there is an inconvenience in the unevenness of the master mold for manufacturing the form shown in FIG. 1B, the unevenness of the replica mold (for example, see FIG. 2C) formed by one-time transfer. Will be able to adjust. As a result, for example, replica molds having various dimensions in which the concavo-convex dimensions are slightly changed can be created from one ready-made master mold having a predetermined concavo-convex pattern. Furthermore, for example, even if the imprint process, material, and etching conditions are changed, a replica mold having the same dimensions can be created from one master mold.

Of course, the invention of the present application is adopted even when the uneven pattern pattern shown in FIG. 1 (B) is made by using an electron beam (EB) lithography method or an optical lithography method other than the nanoimprint method. Thus, the dimension of the concavo-convex pattern can be corrected. This is because even in these methods, there is a case where it is required to cope with only the dimensional correction without recreating the uneven pattern from the beginning.
(3) Dimensional correction film part forming step of forming dimensional correction film part

  Next, as shown in FIG. 1C, the dimension for applying the dimension correcting film part 40 so as to cover the side surface 32 and the upper surface 31 of the convex basic mask part 30 and the upper surface 20 a of the intermediate film 20. A correction film part forming step is performed.

  The film portion 40 for dimensional correction is not particularly limited as long as a series of films are formed in layers along the surface to be deposited, but preferably the ALD method (atomic layer deposition method). It is desirable to use an atomic layer formed by The surface to be deposited may be a surface of any shape such as an uneven surface or a curved surface. By using the ALD method, a film can be accurately formed at a low temperature. Furthermore, step coverage is also very good.

  The thickness of the film portion 40 for dimensional correction can be formed in accordance with the required degree of dimensional correction of the uneven pattern. It may be composed of one atomic layer, or may be composed of two or more atomic layers.

As a preferred embodiment, when the film portion 40 for dimensional correction is composed of one atomic layer, a convex basic mask portion whose temperature when depositing one atomic layer is a resist whose main component is a resin Deposition at a first temperature T _L that is sufficiently lower than the glass transition temperature Tg of the resist constituting the convex base mask portion 30 (for example, 20 to 100 ° C., more preferably room temperature) so as not to damage 30 It is desirable to operate. One atomic layer after deposition may be annealed at a temperature T _H1 higher than the temperature T _L during deposition. As a result, the film strength of the atomic layer itself can be increased, and the adhesion with the bonded product can be increased. The temperature T _H1 can be appropriately selected according to the material constituting the atomic layer, but is set to a temperature range of 200 to 800 ° C., for example.

When the film portion 40 for dimensional correction is composed of two or more atomic layers, a convex basic mask portion made of a resist whose main component is the temperature when depositing the first atomic layer. It is desirable that the deposition operation be performed at a first temperature T _L that is sufficiently lower than the glass transition temperature Tg of the resist (for example, 20 to 100 ° C., more preferably room temperature) so as not to damage 30. Thereafter, the first atomic layer after deposition may be annealed at a temperature T _H1 higher than the temperature T _L during deposition. As a result, the first atomic layer can increase the film strength of the atomic layer itself or increase the adhesion with the bonded product. The temperature T _H1 can be appropriately selected according to the material constituting the atomic layer, but is set to a temperature range of 200 to 800 ° C., for example.

After forming a strong first atomic layer in this way, the second and subsequent atomic layers are deposited in a deposition atmosphere at a temperature T _H2 higher than the temperature T _L when depositing the first atomic layer. It can be deposited sequentially. This is to increase the strength of the atomic layer, increase the adhesion, and increase the efficiency of the process. The temperature T _H2 can be appropriately selected according to the material constituting the atomic layer, but is set to a temperature range of 80 to 600 ° C., for example. The temperature T _H2 may be the same as the annealing temperature T _H1 of the first atomic layer.

The second and subsequent atomic layers are deposited (film formation) at a temperature approximately equal to the temperature _TL for depositing the first atomic layer, and the temperature at which the second atomic layer is deposited after the deposition (film formation) is completed. Annealing may be performed at a temperature T _H1 higher than T _L.

  The film thickness of the dimension correction film portion 40 to be formed may be set to a target correction dimension. For example, the thickness is 50 nm or less, preferably about 0.2 to 10 nm.

Specific examples of the material constituting the dimension correcting film portion 40 include Si-based, Al-based, and Ta-based films.
(4) Etch back process

  Next, as shown in FIG. 1D, an etch-back process is performed in which the dimension correction film portion 40 is etched back to expose the upper surface 20a of the intermediate film 20. Etch back is an operation in which the entire surface is etched in the thickness direction by etching. Note that the etch back is generally over-etched so that the upper surface 20a of the intermediate film 20 can be surely exposed, and the upper surface 20a after the etch back is not necessarily coincident with the upper surface 20a before the etch back. It does not have to be the same plane.

The etch back may be performed using an appropriate etching gas depending on the material constituting the dimension correcting film portion 40. For example, when the dimension correction film portion 40 is made of silicon oxide (SiO ₂ ), etching back can be performed using a fluorine-based gas such as CF ₄ , CHF ₃ , or C ₂ F ₆ as an etching gas. Good.

Thus, the etching mask 50 is formed in a predetermined pattern on the upper surface 20a of the intermediate film 20 as shown in FIG. The etching mask 50 includes a film portion 40 for dimension correction after etching back and a convex basic mask portion 30.
(5) Intermediate film etching process

  Next, as shown in FIG. 2A, an intermediate film etching process is performed in which the intermediate film 20 is etched using the etching mask 50 patterned on the intermediate film 20. By this intermediate film etching step, an intermediate film mask 21 having a predetermined pattern is formed as shown in FIG. In addition, by providing the dimension correcting film portion 40 made of an ALD film on the side surface constituting the etching mask 50, the mask pattern size in the intermediate film etching process is less likely to fluctuate, and the etching accuracy is maintained at a high level. Can be done in the state.

  As described above, the intermediate film 20 can be made of a material having an etching rate smaller than that of the substrate 10 and having etching resistance, such as a metal such as chromium, titanium, tantalum, silicon, and aluminum, or chromium nitride. Chromium compounds such as chromium oxide and chromium oxynitride, tantalum oxide, tantalum oxynitride, tantalum boride, tantalum compounds such as tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride alone, or Two or more combinations can be used.

  When the intermediate film 20 is made of, for example, chromium or a compound containing chromium, the intermediate film 20 can be dry etched using, for example, a mixed gas of oxygen and chlorine as an etching gas.

After the etching process, for example, the remaining part 30a of the basic mask part 30 and the remaining part 40a of the dimension correction film part 40 constituting a part of the etching mask 50 are peeled and removed using a predetermined resist stripping solution or the like. Although it is desirable that only the intermediate film mask 21 shown in FIG. 2B is formed, the etching mask 50 after the etching process may be left as it is.
(6) Substrate etching process

  Next, as shown in FIG. 2C, substrate etching for etching the first main surface portion 11 a of the substrate 10 using the intermediate film mask 21 patterned on the first main surface portion 11 a of the substrate 10. A process is performed.

  In order to etch the substrate 10, it is usually desirable to use dry etching such as reactive gas etching or reactive ion etching.

For the selection of the etching gas for etching the substrate 10, for example, a combination that increases the etching selectivity while considering the material of the intermediate film 20 having excellent etching resistance based on the material of the substrate 10 is appropriately selected. You may make it choose. For example, when the material of the substrate 10 is quartz, the material of the intermediate film 20 is preferably Cr, and the etching gas is preferably a fluorine-based gas such as carbon tetrafluoride (CF ₄ ). For example, when the material of the substrate 10 is silicon, the material of the intermediate film 20 is SiO ₂ and the etching gas is an etching gas containing hydrogen bromide (HBr) or chlorine (Cl ₂ ). preferable.

  After such a substrate etching process, the intermediate film mask 21 is removed, and the nanoimprint mold 1 of the present invention as shown in FIG. 2C is manufactured.

  The dimension of the concavo-convex pattern of the nanoimprint mold 1 of the present invention formed through the above steps (see FIG. 2C) is the dimension of the concavo-convex pattern formed by the convex basic mask portion 30 (FIG. 1B). It can be seen that it was formed by correcting the size by the film portion 40 for size correction. And this nanoimprint mold 1 has the uneven | corrugated | grooved part uniformly comprised by the single material of the board | substrate 10 used for nanoimprint molds, and the layer formed with a different material does not exist in this uneven | corrugated part. Of course, there is no layer formed of the same material as the substrate 10.

  Note that the nanoimprint mold 1 of the present invention does not exclude the formation of a release layer or the like on the concavo-convex portion when used in imprinting.

  In the present embodiment, the convex basic mask portion 30 shown in FIG. 1B can be further treated with oxygen plasma or the like for slimming.

  Next, a second embodiment of the method for producing a nanoimprint mold of the present invention will be described with reference to FIGS.

  <Nanoimprint mold manufacturing method (second embodiment)>

  3 (A) to 3 (D) are cross-sectional views for explaining a process example of the second embodiment in the nanoimprint mold manufacturing method of the present invention over time, and FIGS. 4 (A) to (C). FIG. 5 is a cross-sectional view for explaining a process example of the second embodiment in the nanoimprint mold manufacturing method of the present invention over time, and is a drawing subsequent to the process of FIG. 3D, and FIG. (C) is sectional drawing for demonstrating with time the process example of 2nd Embodiment in the manufacturing method of the nanoimprint mold of this invention, Comprising: It is drawing following the process of FIG.4 (C).

  The manufacturing method of the nanoimprint mold of the present invention in the second embodiment is similar to the case of the first embodiment described above. As a main part thereof, a convex basic mask portion is formed on the substrate via an intermediate film. A basic mask pattern forming process for forming a pattern, and a dimension correcting film part forming process for forming a dimension correcting film part for correcting the dimension of the mask part on the basic mask part. Is done.

  In more detail, the manufacturing method of the nanoimprint mold of the present invention in the second embodiment includes (1) a step of preparing a substrate having a first main surface portion made of a plane, and (2) on the first main surface portion of the substrate. A first mask pattern forming step of patterning the convex first mask portion through the intermediate film, and (3) a first side so as to cover the side surface and the upper surface of the first mask portion and the upper surface of the intermediate film. A first film part forming step for depositing the film part; and (4) etching back the first film part to expose the upper surface of the first mask part and the upper surface of the intermediate film. An etch-back step of forming a side wall protrusion on the side surface of the first mask portion; and (5) removing the first mask portion on the first main surface portion of the substrate via the intermediate film. Convex basic mass composed of membrane part (side wall convex part) A basic mask pattern forming step for patterning the portion, and (6) forming a dimension correcting film portion for forming a dimension correcting film portion so as to cover the side surface and the upper surface of the convex basic mask portion and the upper surface of the intermediate film And (7) an etch back process in which the film portion for dimensional correction is etched back to expose the upper surface of the intermediate film, and (8) an etching pattern formed on the intermediate film by the etch back process. An intermediate film etching process for etching the intermediate film using a mask for the substrate, and (9) an intermediate film etching process using the mask for the intermediate film patterned on the first main surface portion of the substrate. And a substrate etching step for etching the first main surface portion.

Hereinafter, each step will be sequentially described.
(1) The process of preparing the board | substrate which has the 1st main surface part which consists of a plane.

  As shown in FIG. 3A, a substrate 10 for a nanoimprint mold is prepared. A first main surface portion 11a is formed on one main surface 11 of the substrate 10 thus prepared, and an intermediate film 20 is formed on the first main surface portion 11a.

  In FIG. 3A, an example is shown in which the entire area of the principal surface 11 on one side of the substrate 10 constitutes the first principal surface portion 11a composed of a flat surface, but is not limited to this configuration. For example, a substrate 10 having a so-called mesa structure in which only an area where an intermediate film 20 or a convex basic mask portion described later is provided partially constitutes a flat first main surface portion may be provided. The mesa structure is not limited to one stage and may be multistage.

  The material, thickness, and the like of the substrate 10 can be set similarly to those in the first embodiment described above.

  As the intermediate film 20 provided on the substrate 10, a material having an etching rate smaller than that of the substrate 10 and having etching resistance can be used. For example, a metal such as chromium, titanium, tantalum, silicon, and aluminum, nitride Chrome compounds such as chromium, chromium oxide, chromium oxynitride, tantalum oxide, tantalum oxynitride, tantalum boride, tantalum compounds such as tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride, etc. Or it can be used in combination of 2 or more types. The film thickness is usually 50 nm or less, particularly 1 to 20 nm, more preferably about 3 to 10 nm.

  The intermediate film 20 can be formed by, for example, sputtering, vapor deposition, ion plate, or the like.

The intermediate film 20 may be configured as a laminated film having two or more layers.
(2) First mask pattern forming step of patterning the convex first mask portion

  Next, as shown in FIG. 3B, a first mask for pattern-forming a convex first mask portion 130 on the upper surface 20a of the intermediate film 20 formed on the first main surface portion 11a of the substrate 10. A pattern forming process is performed.

  In the second embodiment, the convex first mask portion 130 is preferably composed of a so-called resist whose main component is a resin, for example, by an electron beam (EB) lithography method, a photolithographic method, or a nanoimprint method. The convex first mask part 130 can be patterned.

  When the electron beam (EB) lithography method is used as a first technique, a resist forming step of forming an electron beam sensitive resin film on the intermediate film 20 of the substrate 10 is performed, and then the formed electron beam sensitive Electron beam drawing is performed on the conductive resin film so as to form a desired pattern.

  After the electron beam drawing is completed, a resist developing process for developing the electron beam sensitive resin film is performed. For example, when a positive type electron beam sensitive resin film is used, the unirradiated portion remains as a resist without being decomposed, and the convex first mask portion 130 is formed in a predetermined pattern (a negative type electron beam). When a sensitive resin film is used, the irradiated portion remains as a resist without being decomposed, and a pattern opposite to the positive type is formed).

  As a second method, when the photolithography method is used, a resist forming step for forming a photosensitive resin film is performed on the intermediate film 20 of the substrate 10, and then the desired photosensitive resin film is applied to the desired photosensitive resin film. The exposure operation is performed through the mask pattern so as to form the pattern. After the exposure operation is completed, a resist development process for developing the photosensitive resin film is performed. For example, when a positive photosensitive resin film is used, the unexposed portion remains as a resist without being decomposed, and a convex first mask portion 130 is formed in a predetermined pattern (negative photosensitive resin film). Is used, the exposed portion remains as a resist without being decomposed, and a pattern opposite to the positive type is formed).

  As a third method, when the nanoimprint method is used, for example, a photocurable resin material is supplied and disposed as an object to be transferred on the intermediate film 20 of the substrate 10 by a dispenser, an inkjet, or the like. Next, a mold having a desired concavo-convex structure is brought into contact with the disposed resin material, and pressure is applied as necessary (so-called mold pressing step). In this state, the resin material becomes a resin layer having an uneven structure, and the resin material is cured by irradiating the resin layer with ultraviolet rays (so-called resin curing step). Next, by separating the mold from the resin material, a convex first mask portion 130 in which the concave-convex structure of the mold is inverted is formed on the intermediate film 20 of the substrate 10 in a predetermined pattern. The so-called residual film can be removed by oxygen ashing or the like in a slimming process described later.

  The convex first mask portion 130 referred to in the second embodiment is a structure including a resin material as a main component. Sometimes referred to as a resist.

Moreover, the pattern form of the convex first mask portion 130 is, for example, a so-called line and space form in which the uneven shape is extended in a row in the longitudinal direction, or a form in which the dot shape is dispersed in a predetermined pattern. Alternatively, the hole shape may be distributed in a predetermined pattern, the combined shape of these individual shapes, or a special three-dimensional structure different from these.
(2 ') Slimming process

  In the present embodiment, as shown in FIG. 3C, a slimming process that can be provided as needed is added after the first mask pattern forming process for patterning the convex first mask portion 130. Has been.

  In the slimming process, the convex first mask portion 130 is treated with, for example, oxygen plasma to form a convex first mask portion 130a that is slimmed as shown in FIG.

  In this specification, slimming is to reduce the width of the pattern of the convex first mask portion 130 and reduce the film thickness by wet etching or dry etching (including oxygen plasma treatment). For example, by performing slimming by oxygen plasma treatment, a pattern width of about ½ can be formed without changing the pattern pitch of the convex first mask portion 130 formed first.

Note that the dimensional accuracy may be deteriorated by performing the slimming process for a long time and increasing the degree of slimming (increasing the degree of reduction of the pattern width). In such a case, an attempt is made to design a process for reducing the reduction degree of the slimming width as much as possible, and the reduced amount can be dealt with in a dimension correcting film part forming step for forming a dimension correcting film part to be described later. It becomes possible. For this, refer to the description of the comparison between Example 2 and the reference example described later.
(3) First film portion forming step of depositing the first film portion so as to cover the side surface and upper surface of the first mask portion and the upper surface of the intermediate film

  Next, as shown in FIG. 3D, the first film portion 140 is covered so as to cover the side surface 132 and the upper surface 131 of the slimmed convex first mask portion 130a and the upper surface 20a of the intermediate film 20. A first film part forming step is performed.

  The first film part 140 is not particularly limited as long as a series of films are formed in layers along the surface to be deposited. For example, a dry process such as a CVD method or a self-organization is used. A film formed by chemical conversion or the like can be used, and an atomic layer deposition film formed by an ALD method (atomic layer deposition method) is preferably used. The surface to be deposited may be a surface of any shape such as an uneven surface or a curved surface. By using the ALD method, a film can be accurately formed at a low temperature. Furthermore, step coverage is also very good.

  The first film part 140 may be composed of one layer, or may be composed of a laminated film of two or more layers. The film thickness of the first film part 140 is preferably about the half-pitch designed film thickness, for example, for example, until a thickness of several nm to 50 nm, preferably about 5 to 30 nm is obtained. Atomic layers are stacked sequentially. About the temperature conditions in the case of stacking in multiple layers, it is possible to follow the method for forming the ALD film (dimension correction film portion 40) in the first embodiment described above.

  Examples of the specific material constituting the first film part 140 include Si-based, Al-based, and Ti-based films.

Incidentally, in order to smoothly perform the etch back in the next etch back process, the pattern film thickness is modified so that the recess dimension Dp shown in FIG. In the present invention, it is possible to cope with the dimension correcting film part forming step of forming the dimension correcting film part. For this, refer to the description of the comparison between Example 2 and the reference example described later.
(4) Etch back process

  Next, as shown in FIG. 4A, the first film portion 140 is etched back to expose the upper surface 131 of the convex first mask portion 130a and the upper surface 20a of the intermediate film 20, and the first film portion 140a is exposed. An etch-back process is performed in which a part of the film part 140 is left on the side surface 132 of the first mask part 130a to form the side wall convex part 140a. Etch back is an operation in which the entire surface is etched in the thickness direction by etching.

Etch back may be performed using an appropriate etching gas depending on the material constituting the first film portion 140. For example, in the case where the first film part 140 is made of silicon oxide (SiO ₂ ), etching back may be performed using a fluorine-based gas such as CF ₄ , CHF ₃ , or C ₂ F ₆ as an etching gas. .
(5) Basic mask pattern formation process

  Next, as shown in FIG. 4B, by removing the first mask portion 130a (130), the first film portion 140 is formed on the first main surface portion 11a of the substrate via the intermediate film 20. A basic mask pattern forming step of patterning the convex basic mask portion 140a constituted by the side wall convex portions 140a, which is a part of the mask, is performed.

  In the present invention, the first film part 140 is etched back in the etch back process, which is the previous process, and the upper surface 131 of the first mask part 130a (130) is exposed. One mask part 130a (130) can be easily removed.

  The removal of the first mask portion 130a (130) can be selectively removed by a dry process using an oxygen-based gas. For example, dry processing such as dry etching using oxygen plasma or ozone processing can be cited as a suitable example. The first mask portion 130a (130) is a portion that becomes a so-called core when forming the pattern of the sidewall convex portion 140a (convex basic mask portion 140a) that is a part of the first film portion 140. When a similar convex object made of an inorganic compound is used as the core instead of the first mask portion 130a (130) mainly composed of the resin of this embodiment, the number of steps for forming the inorganic compound increases. In addition, the dry etching selection ratio for removing the inorganic compound core is worse than the case where the first mask portion 130a (130) is used as a core, which causes variation in pattern dimensions. Further, when wet etching is used to remove the inorganic compound core, the pattern of the sidewall convex portion 140a (convex basic mask portion 140a) may be collapsed or deformed due to the surface tension of the wet etching solution.

  In the present invention, by using the resist core of the first mask part 130a (130) and the dry treatment, the pattern of the side wall convex part 140a (convex base mask part 140a) which is a part of the first film part 140 is used. It is possible to minimize the collapse and deformation of the.

  When the removal of the first mask part 130a (130) is completed, the adhesion strength, film strength, etc. of the side wall convex part 140a (convex base mask part 140a) which is a part of the first film part 140 are set. In order to improve the temperature, for example, heat treatment (annealing) at a high temperature of about 200 to 800 ° C. is one of preferred embodiments.

  In the second embodiment of the present invention, as described above, the first mask part 130a (130) is used as a core, and a part of the first film part 140 is formed as a side wall convex part 140a on the side surface. Therefore, as shown in FIG. 4B, when the basic mask pattern forming process for patterning the convex basic mask portion 140a is completed, the pattern of the basic mask portion 140a (side wall convex portion) is viewed from the plane. In this case, a state is formed in which a plurality of basic mask portions 140a (side wall convex portions) forming a closed loop as shown in FIG. 6 are arranged at a predetermined pitch. FIG. 8 is a partial perspective view illustrating the pattern of the basic mask portion 140a (side wall convex portion) so as to be easily understood.

  The basic mask part 140a (side wall convex part) forming one closed loop has a pair of side wall convex parts 145 arranged so as to sandwich the first mask part 130a existing as a core as shown in FIG. 145 (same as 140a).

  In the case of forming a pattern of the side wall convex portion 145 (140a) in the line and space form as shown in FIG. 7 during the manufacture of the nanoimprint mold, the side wall convex portion forming the closed loop shown in FIG. It is necessary to remove both ends 146 in the longitudinal direction of 145 (140a).

  In order to remove both end portions 146 in the longitudinal direction, for example, the side wall protrusions in an exposed state are covered with a resist film as a mask over an area surrounded by abcd in FIG. And a method of etching and removing the vicinity of both end portions 146 of the portion.

  In manufacturing the nanoimprint mold, both end portions 146 in the longitudinal direction of the side wall convex portions forming the closed loop shown in FIG. 6 may be left. In this case, after transferring the concavo-convex transfer pattern of the transfer layer onto the substrate to be processed by an actual nanoimprint operation, defects in the transfer layer caused by the presence of the transferred portion corresponding to the edge are added as necessary. What is necessary is just to process. As the structure of the nanoimprint mold, when both end portions 146 in the longitudinal direction of the side wall convex portion forming a closed loop are left, the effect of collapsing or deforming the side wall convex portion is further increased because of the closed loop. To express. It should be noted that the removal of both end portions 146 in the longitudinal direction of the side wall convex portion forming the closed loop may be performed at any stage as long as the first film portion forming step shown in FIG. 3D is completed.

Note that the finished convex shape is affected by the etch back process in the etch back process in the second embodiment and the removal process operation of the first mask portion 130a (130) serving as the core in the basic mask pattern forming process. The size of the basic mask portion 140a may cause an error from a desired size. Even in such a case, the dimension correcting film part forming step of forming the dimension correcting film part in the next step can be effectively used.
(6) Dimensional correction film part forming step of forming a dimensional correction film part

  Next, as shown in FIG. 4C, the dimension correction film portion 400 is formed so as to cover the side surface 142 and the upper surface 141 of the convex basic mask portion 140a and the upper surface 20a of the intermediate film. A film | membrane part formation process is implemented.

  The dimension correcting film part 400 may be composed of one layer, or may be composed of two or more layers. The film portion 400 for dimensional correction is not particularly limited as long as a series of films are formed in layers along the surface to be deposited, but preferably the ALD method (atomic layer deposition). It is desirable to use an atomic layer formed by the above method. The surface to be deposited may be a surface of any shape such as an uneven surface or a curved surface. By using the ALD method, a film can be accurately formed at a low temperature. Furthermore, step coverage is also very good.

  The thickness of the film part 400 for dimension correction can be formed in accordance with the required degree of dimension correction of the uneven pattern. It may be composed of one atomic layer, or may be composed of two or more atomic layers. The film thickness is, for example, 50 nm or less, preferably about 0.2 to 10 nm.

  Examples of specific materials constituting the dimension correcting film portion 400 include Si-based, Al-based, and Ti-based films.

  The film portion 400 for dimensional correction can be formed at a low temperature (for example, about room temperature to 100 ° C.), or at a high temperature (for example, about 100 to 600 ° C.) in order to improve adhesion strength, film strength, and the like. A film can also be formed. When the film is formed at a low temperature, it is desirable to perform a heat treatment (annealing) at a high temperature of about 200 to 800 ° C., for example, in order to improve adhesion strength, film strength, and the like.

The convex basic mask portion 140a (side wall convex portion 140a) and the dimension correcting film portion 400 deposited thereon are preferably made of the same material. Adhesion between the two films can be improved, and by using the same material, it becomes easy to grasp the behavior of etching or the like in an etch back process to be described later, and the dimensional accuracy can be easily increased.
(7) Etch back process

  Next, as shown in FIG. 5A, an etch back process is performed in which the dimension correction film portion 400 is etched back to expose the upper surface 20a of the intermediate film 20.

  By this step, an etching mask 150 is formed. The etching mask 150 includes a convex basic mask portion 140a and a dimension correcting film portion 400. Normally, when the upper surface 20a of the intermediate film 20 is exposed, the upper surface 141 of the convex basic mask portion 140a is also exposed, but the exposure of the upper surface 141 is not an essential requirement. This is because it is sufficient to function as an etching mask. The etch back is generally over-etched so that the upper surface 20a of the intermediate film 20 can be surely exposed, and the upper surface 20a of the intermediate film 20 after the etch back is not necessarily before the etch back. It may not be the same plane that coincides with the upper surface 20a of the intermediate film 20.

  Etch back refers to an operation of etching the entire surface in the thickness direction by etching.

The etch back may be performed using an appropriate etching gas depending on the material constituting the dimension correction film portion 400. For example, when the dimension correcting film portion 400 is made of silicon oxide (SiO ₂ ), etching back is performed using a fluorine-based gas such as CF ₄ , CHF ₃ , or C ₂ F ₆ as an etching gas. Can do.
(8) Intermediate film etching process

  Next, as shown in FIG. 5B, an intermediate film etching process is performed in which the intermediate film 20 is etched using the etching mask 150 patterned on the upper surface 20a of the intermediate film 20 by the etch back process. Is done.

  By this intermediate film etching step, an intermediate film mask 21 having a predetermined pattern is formed.

  As described above, the intermediate film 20 can be made of a material having an etching rate smaller than that of the substrate 10 and having etching resistance. For example, a metal such as chromium, titanium, tantalum, silicon, and aluminum, chromium nitride, oxide Chromium, chromium-based compounds such as chromium oxynitride, tantalum compounds such as tantalum oxide, tantalum oxynitride, tantalum boride, tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride, etc. It can be used in combinations of more than one species.

  When the intermediate film 20 is made of, for example, chromium or a compound containing chromium, the intermediate film 20 can be dry etched using, for example, a mixed gas of oxygen and chlorine as an etching gas.

After the etching process, the etching mask 150 formed on the intermediate film mask 21 can be left as it is, or can be removed to make only the intermediate film mask 21.
(9) Substrate etching process

  Next, a substrate etching process for etching the first main surface portion 11 a of the substrate 10 is performed using the intermediate film mask 21 patterned on the first main surface portion 11 a of the substrate 10.

  In order to etch the substrate 10, it is usually desirable to use dry etching such as reactive gas etching or reactive ion etching.

For the selection of the etching gas for etching the substrate 10, for example, a combination that increases the etching selectivity while considering the material of the intermediate film 20 having excellent etching resistance based on the material of the substrate 10 is appropriately selected. You may make it choose. For example, when the material of the substrate 10 is quartz, the material of the intermediate film 20 is preferably Cr, and the etching gas is preferably a fluorine-based gas such as carbon tetrafluoride (CF ₄ ). For example, when the material of the substrate 10 is silicon, the material of the intermediate film 20 is SiO ₂ and the etching gas is an etching gas containing hydrogen bromide (HBr) or chlorine (Cl ₂ ). preferable.

  After such a substrate etching process, the intermediate film mask 21 is removed, and the nanoimprint mold 101 of the present invention as shown in FIG. 5C is manufactured.

  The dimensions of the concavo-convex pattern of the nanoimprint mold 101 of the present invention formed through the above steps (see FIG. 5C) are the dimensions of the concavo-convex pattern formed by the convex basic mask portion 140a (FIG. 4B). It can be seen that it was formed by correcting the size by the film portion 400 for size correction. And this nanoimprint mold 101 has the uneven | corrugated | grooved part uniformly comprised by the single material of the board | substrate 10 used for nanoimprint molds, and the layer formed with a different material does not exist in this uneven | corrugated part. Of course, there is no layer formed of the same material as the substrate 10.

  Note that the nanoimprint mold 101 of the present invention does not exclude the formation of a release layer or the like on the uneven portion when used in imprinting.

  <Method for Manufacturing Nanoimprint Mold (Third Embodiment)>

  FIGS. 9A to 9D are cross-sectional views for explaining a process example of the third embodiment over time in the method for producing a nanoimprint mold of the present invention, and FIGS. 10A to 10D. These are sectional drawings for demonstrating with time the process example of 3rd Embodiment in the manufacturing method of the nanoimprint mold of this invention, and are drawings following the process of FIG.9 (D).

  The manufacturing method of the nanoimprint mold of the present invention in the third embodiment is similar to the case of the first embodiment described above in that a convex basic mask portion is formed on the substrate via an intermediate film as the main portion. A basic mask pattern forming process for forming a pattern, and a dimension correcting film part forming process for forming a dimension correcting film part for correcting the dimension of the mask part on the basic mask part. Is done.

  In more detail, the manufacturing method of the nanoimprint mold of the present invention in the third embodiment includes (1) a step of preparing a substrate having a first main surface portion made of a plane, and (2) on the first main surface portion of the substrate. A first mask pattern forming step of forming a basic mask material layer made of an inorganic material through an intermediate film and patterning a convex first mask portion on the basic mask material layer; (3) A basic mask pattern forming step of patterning a convex basic mask portion on the intermediate film by etching the basic mask material layer using the first mask portion as an etching mask and removing the first mask portion; (4) A dimension correcting film part forming step of forming a dimension correcting film part so as to cover the side surface and upper surface of the convex basic mask part and the upper surface of the intermediate film; and (5) etching the film part for dimension correction. An etch-back process for exposing the upper surface of the intermediate film, and (6) an intermediate film etching process for etching the intermediate film using an etching mask patterned on the intermediate film by the etch-back process; And (7) a substrate etching step for etching the first main surface portion of the substrate by using the intermediate film mask patterned on the first main surface portion of the substrate by the intermediate film etching step. Is done.

Hereinafter, each step will be sequentially described.
(1) The process of preparing the board | substrate which has the 1st main surface part which consists of a plane.

  As shown in FIG. 9A, a substrate 10 for nanoimprint mold is prepared. A first main surface portion 11a is formed on one main surface 11 of the substrate 10 thus prepared, and a basic mask made of an inorganic material via an intermediate film 20 is formed on the first main surface portion 11a. A material layer 230 'is formed.

  In FIG. 9A, an example is shown in which the entire main area 11 on one side of the substrate 10 constitutes the first main surface portion 11a composed of a flat surface, but is not limited to this configuration. For example, the substrate 10 having a so-called mesa structure in which only the area where the intermediate film 20, the basic mask material layer 230 ′, and a convex basic mask portion described later are provided partially constitutes a first main surface portion that is a flat surface. You can also. The mesa structure is not limited to one stage and may be multistage.

  The material, thickness, and the like of the substrate 10 can be set similarly to those in the first embodiment described above.

  As the intermediate film 20 provided on the substrate 10, a material having an etching rate smaller than that of the substrate 10 and having etching resistance can be used. For example, a metal such as chromium, titanium, tantalum, silicon, and aluminum, nitride Chrome compounds such as chromium, chromium oxide, chromium oxynitride, tantalum oxide, tantalum oxynitride, tantalum boride, tantalum compounds such as tantalum oxynitride, titanium nitride, silicon nitride, silicon oxynitride, etc. Or it can be used in combination of 2 or more types. The film thickness is usually 50 nm or less, particularly 1 to 20 nm, more preferably about 3 to 10 nm.

  The intermediate film 20 can be formed by, for example, sputtering, vapor deposition, ion plate, or the like.

  The intermediate film 20 may be configured as a laminated film having two or more layers.

  The basic mask material layer 230 ′ provided on the intermediate film 20 has an etching rate smaller than that of the intermediate film 20 and has etching resistance, and etching selectivity (basic mask material) with respect to the first mask portion formed in a later process. The etching rate of the layer 230 ′ / the etching rate of the first mask part) is larger and better than the etching selectivity of the intermediate film 20 with respect to the first mask part (the etching rate of the intermediate film 20 / the etching rate of the first mask part). A certain material can be used, for example, silicon, chromium, titanium, tantalum, molybdenum, etc., and these oxides, nitrides, carbides, oxynitrides, etc. are used alone or in combination of two or more. can do. The film thickness is usually 50 nm or less, particularly 1 to 20 nm, more preferably about 3 to 10 nm.

  The basic mask material layer 230 ′ can be formed by, for example, sputtering, vapor deposition, ion plate, or the like.

The basic mask material layer 230 ′ may be configured as a laminated film of two or more layers.
(2) First mask pattern forming step of patterning the convex first mask portion

  Next, as shown in FIG. 9B, a first mask pattern forming step of patterning a convex first mask portion 235 on the basic mask material layer 230 ′ is performed.

  The convex first mask portion 235 can be formed of a so-called resist whose main component is a resin. For example, the convex first mask portion can be formed by an electron beam (EB) lithography method, a photolithographic method, or a nanoimprint method. 235 can be patterned.

  When the electron beam (EB) lithography method is used as the first technique, a resist forming step of forming an electron beam sensitive resin film is performed on the basic mask material layer 230 ′, and then the formed electron beam sensitive is performed. Electron beam drawing is performed on the conductive resin film so as to form a desired pattern.

  After the electron beam drawing is completed, a resist developing process for developing the electron beam sensitive resin film is performed. For example, when a positive electron beam sensitive resin film is used, the unirradiated portion remains as a resist without being decomposed, and a convex first mask portion 235 is formed in a predetermined pattern (a negative electron beam). When a sensitive resin film is used, the irradiated portion remains as a resist without being decomposed, and a pattern opposite to the positive type is formed).

  As a second method, when the photolithography method is used, a resist forming step for forming a photosensitive resin film is performed on the basic mask material layer 230 ′, and then the photosensitive resin film thus formed is desired. The exposure operation is performed through the mask pattern so as to form the pattern. After the exposure operation is completed, a resist development process for developing the photosensitive resin film is performed. For example, when a positive photosensitive resin film is used, the unexposed portion remains as a resist without being decomposed, and a convex first mask portion 235 is formed in a predetermined pattern (a negative photosensitive resin film). Is used, the exposed portion remains as a resist without being decomposed, and a pattern opposite to the positive type is formed).

  As a third method, when the nanoimprint method is used, for example, a photocurable resin material is supplied and arranged as a transfer object on the basic mask material layer 230 ′ by a dispenser, an inkjet, or the like. Next, a mold having a desired concavo-convex structure is brought into contact with the disposed resin material, and pressure is applied as necessary (so-called mold pressing step). In this state, the resin material becomes a resin layer having an uneven structure, and the resin material is cured by irradiating the resin layer with ultraviolet rays (so-called resin curing step). Next, by separating the mold from the resin material, a convex first mask portion 235 in which the concavo-convex structure of the mold is inverted is formed on the intermediate film 20 of the substrate 10 in a predetermined pattern. The so-called residual film can be removed by oxygen ashing or the like in a slimming process described later.

The pattern form of the convex first mask portion 235 is, for example, a so-called line-and-space form in which the concavo-convex shape is sequentially extended in the longitudinal direction, or a form in which the dot shape is dispersed in a predetermined pattern. Alternatively, the hole shape may be distributed in a predetermined pattern, the combined shape of these individual shapes, or a special three-dimensional structure different from these.
(3) Basic mask pattern formation process

Then, by etching the foundation mask material layer 230 'of the first mask portion 235 as an etching mask as shown in FIG. 9 (C), by removing the first mask portion 235, convex on the intermediate layer 20 The basic mask portion 230 is patterned.

Foundation mask material layer 230 'selection of the etching gas for etching, for example, foundation mask material layer 230' with a consideration of the material of the first mask part 235, the etching of the foundation mask material layer 230 ' What is necessary is just to select suitably the combination that a selection ratio becomes large. For example, a silicon oxide foundation mask material layer 230 ', when the first mask 235 is resist, it is preferable that the etching gas and fluorine-based gas such as CF _4, CHF _3.

In the etching of such first mask portion 235 foundation mask material layer 230 as an etching mask ', for example, the resist is compared to the etching of the chromium film as an etching mask, resist selectivity is good. For this reason, the thickness of the first mask portion 235 as an etching mask may be thin. For example, in the formation of the first mask portion 235 using the nanoimprint method which is the third method, the pattern collapses, mold release The occurrence of defects at the time can be reduced.
(4) Dimensional correction film part forming step for forming a dimensional correction film part

  Next, as shown in FIG. 9D, the dimension correcting film part 240 is formed so as to cover the side surface 232 and the upper surface 231 of the convex base mask part 230 and the upper surface 20a of the intermediate film. A film | membrane part formation process is implemented.

  The film portion 240 for dimensional correction may be composed of one layer or a laminated film of two or more layers. The film portion 240 for dimensional correction is not particularly limited as long as a series of films are formed in layers along the surface to be deposited, but preferably the ALD method (atomic layer deposition). It is desirable to use an atomic layer formed by the above method. The surface to be deposited may be a surface of any shape such as an uneven surface or a curved surface. By using the ALD method, step coverage is very good. Further, in the third embodiment, since the basic mask portion 230 is made of an inorganic material, the heat resistance is high. Therefore, the thermal ALD method can be adopted and can be used as the film portion 240 for dimensional correction. While the range of selection of materials is expanded, a more precise dimensional correction film portion 240 can be formed.

  The thickness of the film portion 240 for dimensional correction can be formed in accordance with the required degree of dimensional correction of the uneven pattern. It may be composed of one atomic layer, or may be composed of two or more atomic layers. The film thickness is, for example, 50 nm or less, preferably about 0.2 to 10 nm.

  Specific examples of the material constituting the dimension correcting film portion 240 include Si-based, Al-based, and Ti-based films.

  The film portion 240 for dimensional correction can be formed at a low temperature (for example, room temperature to about 100 ° C.), and the heat resistance of the basic mask portion 230 is high as described above. In order to improve, it can also form into a film at high temperature (for example, about 100-600 degreeC). When the film is formed at a low temperature, heat treatment (annealing) can be performed at a high temperature of about 200 to 800 ° C., for example, in order to improve adhesion strength, film strength, and the like.

The convex basic mask portion 230 and the dimension correcting film portion 240 deposited thereon are preferably made of the same material. Adhesion between the two films can be improved, and by using the same material, it becomes easy to grasp the behavior of etching or the like in an etch back process to be described later, and the dimensional accuracy can be easily increased.
(5) Etch back process

  Next, as shown in FIG. 10A, an etch-back process is performed in which the dimension correction film portion 240 is etched back to expose the upper surface 20a of the intermediate film 20.

  By this step, an etching mask 250 is formed. The etching mask 250 includes a convex basic mask portion 230 and a dimension correcting film portion 240. Normally, when the upper surface 20a of the intermediate film 20 is exposed, the upper surface 231 of the convex basic mask portion 230 is also exposed, but the exposure of the upper surface 231 is not an essential requirement. This is because it is sufficient to function as an etching mask. The etch back is generally over-etched so that the upper surface 20a of the intermediate film 20 can be surely exposed, and the upper surface 20a of the intermediate film 20 after the etch back is not necessarily before the etch back. It may not be the same plane that coincides with the upper surface 20a of the intermediate film 20.

The etch back may be performed using an appropriate etching gas depending on the material constituting the dimension correcting film part 240. For example, when the dimension correction film portion 240 is made of silicon oxide (SiO ₂ ), etching back is performed using a fluorine-based gas such as CF ₄ , CHF ₃ , or C ₂ F ₆ as an etching gas. Can do.

In the third embodiment, since the basic mask portion 230 is made of an inorganic material and has high cleaning resistance, after the basic mask portion 230 is patterned in the basic mask pattern forming step, the dimension correction film is formed. After forming the film portion 240 for dimension correction in the portion forming step and after forming the etching mask 250 in the etch back step, a cleaning process such as sulfuric acid / hydrogen peroxide cleaning may be performed. Good. Thereby, generation | occurrence | production of the defect resulting from foreign material adhesion etc. can be reduced.
(6) Intermediate film etching process

  Next, as shown in FIG. 10B, an intermediate film etching process is performed in which the intermediate film 20 is etched using the etching mask 250 patterned on the upper surface 20a of the intermediate film 20 by the etch back process. Is done.

  By this intermediate film etching step, an intermediate film mask 21 having a predetermined pattern is formed.

  As described above, the intermediate film 20 can be made of a material having a lower etching rate than the substrate 10 and having etching resistance. For example, when the intermediate film 20 is made of chromium or a compound containing chromium, the intermediate film 20 is etched. As the gas, for example, a mixed gas of oxygen and chlorine can be used to dry-etch the intermediate film 20.

After the etching process, the etching mask 250 formed on the intermediate film mask 21 can be left as it is, or can be removed to make only the intermediate film mask 21.
(7) Substrate etching process

  Next, as shown in FIG. 10C, substrate etching for etching the first main surface portion 11 a of the substrate 10 using the intermediate film mask 21 patterned on the first main surface portion 11 a of the substrate 10. A process is performed.

  In order to etch the substrate 10, it is usually desirable to use dry etching such as reactive gas etching or reactive ion etching.

For the selection of the etching gas for etching the substrate 10, for example, a combination that increases the etching selectivity while considering the material of the intermediate film 20 having excellent etching resistance based on the material of the substrate 10 is appropriately selected. You may make it choose. For example, when the material of the substrate 10 is quartz, the material of the intermediate film 20 is preferably chromium, and the etching gas is preferably a fluorine-based gas such as carbon tetrafluoride (CF ₄ ). For example, when the material of the substrate 10 is silicon, the material of the intermediate film 20 is silicon oxide, and the etching gas is an etching gas containing hydrogen bromide (HBr) or chlorine (Cl ₂ ). preferable.

  After such a substrate etching process, the intermediate film mask 21 is removed, and the nanoimprint mold 201 of the present invention as shown in FIG. 10D is manufactured.

  The dimension of the concavo-convex pattern (see FIG. 10D) of the nanoimprint mold 201 of the present invention formed through the above steps is the dimension of the concavo-convex pattern formed by the basic mask portion 230 (see FIG. 9C). It can be seen that the film is formed by correcting the size by the film portion 240 for correcting the size. And this nanoimprint mold 201 has the uneven | corrugated | grooved part homogeneously comprised with the single material of the board | substrate 10 used for nanoimprint mold, and the layer formed with a different material does not exist in this uneven | corrugated part. Of course, there is no layer formed of the same material as the substrate 10.

  Note that the nanoimprint mold 201 of the present invention does not exclude the formation of a release layer or the like on the concavo-convex portion when used in imprinting.

Hereinafter, the present invention will be described in more detail with reference to specific examples.
Example 1

  <Nanoimprint mold manufacturing method (first embodiment: see FIGS. 1 to 2)>

  In Example 1, the concave / convex dimensions of the master mold having a concave-convex pattern width of 30 nm and a pitch of 60 nm in a line-and-space pattern are transferred once to change the convex pattern width to 35 nm and the concave pattern width of 25 nm. An object of the present invention is to obtain a replica mold having an uneven pattern.

  First, a synthetic quartz glass substrate having an outer shape of 6 inches square and a thickness of 0.25 inches was prepared as the light transmissive substrate 10. A Cr film 20 (intermediate film 20) having a film thickness of 5 nm was formed on one main surface of the prepared substrate 10 by sputtering with Cr. The Cr film 20 in this embodiment is for forming a so-called hard mask layer.

  Next, a nano-imprint method and oxygen ashing for removing the residual film were performed on the Cr film 20 using a master mold having a concave and convex pattern width of 30 nm and a pitch and line pattern of 60 nm, and a convex pattern width of 30 nm. A resist (convex base mask portion 30) having a line-and-space pattern with a pitch of 60 nm was formed. The thickness of the resist (convex base mask portion 30) was 60 nm.

A dimension correcting film portion 40 was formed so as to cover the side surface 32 and the upper surface 31 of the convex basic mask portion 30 formed in this way and the upper surface 20a of the Cr film 20. The dimension correction film portion 40 is a SiO ₂ film formed by the ALD method, and the film thickness is 2.5 nm.

When forming the SiO ₂ film by the ALD method, the first temperature T _L (film formation temperature) when depositing the first atomic layer was set to room temperature (23 ° C.).

Next, the SiO ₂ coating film, which is the film portion 40 for dimension correction, was etched back by 3 nm (0.5 nm overetching) in the thickness direction by dry etching using CF ₄ gas.

As a result, the dimension correcting film part 40 formed on the Cr film 20 and the dimension correcting film part 40 formed on the upper surface 31 of the convex basic mask part 30 are removed, and the convex part is removed. An etching mask 50 composed of the basic mask portion 30 (resist) and the dimension correcting film portion 40 (SiO ₂ film) formed on the side surface 32 was formed.

  Next, the Cr film 20 was etched using the etching mask 50 patterned on the intermediate film 20 by an etch back process. Etching of the Cr film 20 was performed by dry etching using a mixed gas of oxygen and chlorine.

Next, an etching mask 50 composed of a convex basic mask portion 30 (resist) and a dimension correcting film portion 40 (SiO ₂ film) formed on the side surface 32 is removed with a resist stripping solution and cleaning (sulfuric acid and megasonic). The quartz glass substrate is dry-etched using CF ₄ gas using the intermediate film mask 21 made of a Cr film formed in a predetermined pattern on the substrate as a mask. A concave portion having a depth of 50 nm was formed on the surface portion.

Next, the intermediate film mask 21 made of a Cr film is removed by wet etching with a ceric ammonium nitrate aqueous solution, and the first main surface portion of the quartz glass substrate is resized to have a convex pattern width of 35 nm and a concave pattern width of 25 nm. Could be manufactured.
(Example 2)

  <Nanoimprint mold manufacturing method (second embodiment: see FIGS. 3 to 5)>

  A synthetic quartz glass substrate having an outer shape of 6 inches square and a thickness of 0.25 inches was prepared as the light transmissive substrate 10. A Cr film 20 (intermediate film 20) having a film thickness of 5 nm was formed on one main surface of the prepared substrate 10 by sputtering with Cr. The Cr film 20 in this embodiment is for forming a so-called hard mask layer.

  Next, a nano-imprint method and oxygen ashing for removing the residual film were performed on the Cr film 20 using a master mold having a line pattern with a concave pattern width of 30 nm and a pitch of 80 nm, and a convex pattern width of 30 nm. A resist (convex first mask portion 130) having a line and space pattern with a pitch of 80 nm was formed. The thickness of the resist (the convex first mask portion 130) was 50 nm.

  Next, slimming was performed on the pattern of the formed convex first mask portion 130 by oxygen plasma treatment, and the pattern width of the convex first mask portion 130a after slimming was set to 22 nm. The resist thickness was 44 nm. The degree of reduction of the resist width was [(30-22) / 30] × 100 = 26.7%.

A SiO ₂ film is formed by the ALD method so as to cover the side surface 132 and the upper surface 131 of the pattern of the slimmed convex first mask portion 130a and the upper surface 20a of the Cr film 20, and the SiO ₂ coating film having a thickness of 18 nm is formed. (First film part 140) was formed. The film forming temperature was room temperature. At this time, the recess dimension Dp shown in FIG. 3D was 22 nm.

Next, the entire surface of the SiO ₂ coating film (first film portion 140) is etched back by dry etching using CF ₄ gas to expose the convex first mask portion 130a and the Cr film 20, and Side wall convex portions 140a were formed by leaving one film portion 140 (a coating film of SiO ₂ ) on the side surface of the convex first mask portion 130a.

Next, the first mask portion 130a having a convex shape was selectively removed by dry etching using oxygen plasma (resist core removal operation), and a substrate having the SiO ₂ sidewall convex portion 140a formed on the Cr film 20 was produced. . The side wall convex part 140a of SiO ₂ was a line and space pattern form with a convex part pattern width of 18 nm, a thickness (height) of 40 nm, and a pitch of 40 nm (concave part pattern width of 22 nm).

  Such a side wall convex portion 140a corresponds to the convex basic mask portion 140a in the second embodiment of the present invention.

Next, the SiO ₂ film which is the film portion 400 for dimension correction by the ALD method so as to cover the side surface 142 and the upper surface 141 of the pattern of the side wall convex portion 140a (convex base mask portion 140a) and the upper surface 20a of the Cr film 20. Was deposited to a thickness of 1 nm. By forming the dimension correction film part 400, a new composite convex body composed of the convex basic mask part 140a and the dimension correction film part 400 has a convex part pattern width of 20 nm and a pitch of 40 nm. It became the form of line and space.

Next, the SiO ₂ coating film, which is the film portion 400 for dimension correction, was etched back by 1.5 nm in the thickness direction (0.5 nm over-etching) using CF ₄ gas.

As a result, the dimension correcting film part 400 formed on the Cr film 20 and the dimension correcting film part 400 formed on the upper surface 141 of the convex basic mask part 140a are removed, and the convex part is removed. An etching mask 150 including the basic mask portion 140 (SiO ₂ film) and the dimension correcting film portion 400 (SiO ₂ film) formed on the side surface 142 thereof was formed.

  Next, the Cr film 20 (intermediate film 20) was etched using the etching mask 150 patterned on the Cr film 20 to form an intermediate film mask 21 made of a Cr film. Etching of the Cr film 20 was performed by dry etching using a mixed gas of oxygen and chlorine.

Next, the quartz glass substrate is dry-etched using CF ₄ gas with the intermediate film mask 21 which is a Cr film formed in a predetermined pattern on the substrate as a mask, and a depth is formed in the first main surface portion of the quartz glass substrate. A 50 nm recess was formed.

Next, the intermediate film mask 21 which is a Cr film is removed by wet etching with a ceric ammonium nitrate aqueous solution, and a replica mold having a convex pattern width of 20 nm and a concave pattern width of 20 nm (pitch of 40 nm) is formed on the first main surface portion of the quartz glass substrate. Could be manufactured. This replica mold could be manufactured by correcting the dimensions of the convex basic mask part 140a (line and space with a convex part pattern width of 18 nm and a pitch of 40 nm) in the intermediate process obtained as a result of the resist core removal operation. Is.
(Example 3)

  <Method for Manufacturing Nanoimprint Mold (Third Embodiment: See FIGS. 9 to 10)>

A synthetic quartz glass substrate having an outer shape of 6 inches square and a thickness of 0.25 inches was prepared as the light transmissive substrate 10. A Cr film 20 (intermediate film 20) having a film thickness of 5 nm is formed on one main surface of the prepared substrate 10 by sputtering, and silicon oxide (SiO ₂ ) is formed on the Cr film 20. A basic mask material layer 230 ′ having a thickness of 2.5 nm was formed by sputtering. The Cr film 20 in this embodiment is for forming a so-called hard mask layer.

  Next, a nano-imprint method and oxygen ashing for residual film removal are performed on the basic mask material layer 230 ′ using a master mold having a line-and-space pattern with a concave pattern width of 30 nm and a pitch of 30 nm, and a convex pattern A resist (convex first mask portion 235) having a line-and-space pattern form with a width of 30 nm and a pitch of 30 nm was formed. The thickness of the resist (the convex first mask portion 235) was 30 nm.

Next, the basic mask material layer 230 ′ was dry etched using CF ₄ gas with the first mask portion 235 as an etching mask. Thereafter, the first mask portion 235 was removed by dry etching using oxygen plasma, thereby forming a convex basic mask portion 230 on the Cr film 20. The basic mask portion 230 was a line-and-space pattern having a convex pattern width of 30 nm and a pitch of 30 nm.

The film portion 240 for dimension correction was formed so as to cover the side surface 232 and the upper surface 231 of the convex basic mask portion 230 formed in this way and the upper surface 20a of the Cr film 20. The dimension correction film portion 40 is a SiO ₂ film formed by the ALD method, and the film thickness is 2.5 nm.

The temperature at the time of forming the SiO ₂ film by the ALD method was set to 28 ° C.

Next, the SiO ₂ film as the dimension correcting film portion 240 was etched back by 3 nm in the thickness direction (0.5 nm overetching) by using CF ₄ gas.

Thus, the dimension correcting film part 240 formed on the Cr film 20 and the dimension correcting film part 240 formed on the upper surface 231 of the convex base mask part 230 are removed, and the convex part is removed. An etching mask 250 composed of the base mask portion 230 and the dimension correcting film portion 240 (SiO ₂ film) formed on the side surface 232 was formed.

  Next, sulfuric acid / hydrogen peroxide cleaning was performed, and then the Cr film 20 was etched using the etching mask 250. Etching of the Cr film 20 was performed by dry etching using a mixed gas of oxygen and chlorine.

Next, the etching mask 250 composed of the convex basic mask portion 230 (SiO ₂ film) and the dimension correcting film portion 240 (SiO ₂ film) formed on the side surface 232 is cleaned (sulfuric acid and megasonic cleaning). The quartz glass substrate is dry-etched using CF ₄ gas with the intermediate film mask 21 made of a Cr film formed in a predetermined pattern on the substrate as a mask, and the first main surface portion of the quartz glass substrate is etched. A recess having a depth of 50 nm was formed.

Next, the intermediate film mask 21 made of a Cr film is removed by wet etching with a ceric ammonium nitrate aqueous solution, and the first main surface portion of the quartz glass substrate is resized to have a convex pattern width of 35 nm and a concave pattern width of 25 nm. Could be manufactured.
(Reference example)

  <Manufacturing method of nanoimprint mold without using film part 400 for dimension correction>

  As in the case of Example 2 described above, the nanoimprint method was performed on the Cr film 20 using a master mold having a line-and-space pattern with a concave pattern width of 30 nm and a pitch of 80 nm, and a convex pattern width of 30 nm and a pitch of 80 nm. A resist having a line and space pattern was formed.

  Further, this resist pattern was slimmed by oxygen plasma treatment, and the resist pattern width after slimming was set to 2/3, 20 nm. In this case, the width reduction degree was [(30-20) / 30] × 100 = 33%.

A SiO ₂ film was formed by ALD so as to cover the slimmed resist and the chromium film 20 to form a SiO ₂ coating film (first film portion 140) having a thickness of 20 nm. At this time, the recess dimension Dp in FIG. 3D was 20 nm.

Next, the entire surface of the SiO ₂ coating film (first film portion 140) is etched back by dry etching using CF ₄ gas to expose the convex first mask portion 130a and the Cr film 20, and Side wall convex portions 140a were formed by leaving one film portion 140 (a coating film of SiO ₂ ) on the side surface of the convex first mask portion 130a.

Next, the first mask portion 130a having a convex shape was selectively removed by dry etching using oxygen plasma (resist core removal operation), and a substrate having the SiO ₂ sidewall convex portion 140a formed on the Cr film 20 was produced. .

  Next, the Cr film 20 was etched using the side wall protrusions 140a patterned on the Cr film 20 as a mask, thereby forming an intermediate film mask 21 made of a Cr film.

Next, the quartz glass substrate is dry-etched using CF ₄ gas with the intermediate film mask 21 which is a Cr film formed in a predetermined pattern on the substrate as a mask, and a depth is formed in the first main surface portion of the quartz glass substrate. A 50 nm recess was formed.

Next, the intermediate film mask 21 which is a Cr film is removed by wet etching with a ceric ammonium nitrate aqueous solution, and a replica mold having a convex pattern width of 20 nm and a concave pattern width of 20 nm (pitch of 40 nm) is formed on the first main surface portion of the quartz glass substrate. Manufactured. The uneven pattern size is the same as that of the second embodiment.
<Consideration of Comparison between Example 2 and Reference Example>

  Since the second embodiment includes a process capable of correcting the dimensions, the embodiment 2 can flexibly cope with the dimensional variation of the uneven pattern. Further, by including a process capable of dimension correction, it is possible to reduce the reduction degree of the resist width by slimming, thereby improving the slimming dimension accuracy. Further, by including a process capable of correcting the dimension, the recess dimension Dp can be increased, and the etch-back process can be performed smoothly.

  The present invention can be used in technical fields that require various fine processing, and can be applied to, for example, the manufacture of electronic components including a semiconductor integrated circuit and high-density recording media.

DESCRIPTION OF SYMBOLS 10 ... Board | substrate 11 ... Main surface 11a ... 1st main surface part 20 ... Intermediate film 21 ... Intermediate film mask 30, 230 ... Convex-shaped basic mask part 40, 240, 400 ... Film part 130, 130a, 235 ... for dimension correction Convex first mask part 140... First film part 140 a. Side wall convex part, convex basic mask part 230 ′. Basic mask material layer 1, 101, 201.

Claims (6)

A basic mask pattern forming step of patterning a convex basic mask portion, which is a resist mainly composed of a resin, on an intermediate film on the first main surface portion of a substrate having a first main surface portion made of a plane. When,
A dimension correcting film for forming a dimension correcting film part for correcting the dimension of the convex basic mask part so as to cover the side surface and upper surface of the convex basic mask part and the upper surface of the intermediate film. Part forming step;
Etch back the dimension correction film portion to expose the upper surface of the intermediate film; and
An intermediate film etching step of etching the intermediate film using an etching mask patterned on the intermediate film by the etch back step;
A substrate etching step of etching the first main surface portion of the substrate by using the intermediate film mask patterned on the first main surface portion of the substrate by the intermediate film etching step;
In the dimension correcting film portion forming step, the glass transition temperature Tg of the resist constituting the convex basic mask portion is lower on the side and upper surfaces of the convex basic mask portion and the upper surface of the intermediate film. ALD process at a temperature T _L (atomic layer deposition) by depositing a first layer of atomic layers, and facilities annealed to atomic layer of the first layer at the temperature T _L is higher than the temperature T _H1, the temperature By sequentially depositing the second and subsequent atomic layers by an ALD method (atomic layer deposition method) at a temperature T _H2 higher than T _{L, the} dimension correction film portion composed of a plurality of atomic layers is formed. A method for producing a nanoimprint mold, comprising: forming a nanoimprint mold. A first mask pattern for patterning a convex first mask portion, which is a resist mainly composed of a resin, on an intermediate film on the first main surface portion of a substrate having a first main surface portion made of a plane. Forming process;
A first film portion forming step of depositing a first film portion so as to cover a side surface and an upper surface of the convex first mask portion and an upper surface of the intermediate film;
Etch back the first film portion to expose the upper surface of the first mask portion and the upper surface of the intermediate film, and leave the first film portion on the side surface of the first mask portion to form a side wall protrusion. Etch back process to be formed as,
A basic mask pattern for patterning a convex basic mask portion constituted by the side wall convex portions on the first main surface portion of the substrate by removing the first mask portion via the intermediate film. Forming process;
A dimension correcting film for forming a dimension correcting film part for correcting the dimension of the convex basic mask part so as to cover the side surface and upper surface of the convex basic mask part and the upper surface of the intermediate film. Part forming step;
Etch back the dimension correction film portion to expose the upper surface of the intermediate film; and
An intermediate film etching step of etching the intermediate film using an etching mask patterned on the intermediate film by the etch back step;
A substrate etching step of etching the first main surface portion of the substrate using an intermediate film mask patterned on the first main surface portion of the substrate by the intermediate film etching step;
In the basic mask pattern forming step, after removing the first mask portion, an annealing treatment is performed on the side wall convex portion at 200 to 800 ° C. to thereby form a convex basic mask portion composed of the side wall convex portions. Pattern formation,
In the dimension correcting film portion forming step, a first atomic layer is formed on the side surface and upper surface of the convex base mask portion and the upper surface of the intermediate film by an ALD method (atomic layer deposition method) at a predetermined temperature. depositing said predetermined and facilities annealed to atomic layer of the first layer at a temperature higher than the temperature, the predetermined ALD process at a temperature higher than the temperature (atomic layer deposition) by second and subsequent layers of atoms A method of manufacturing a nanoimprint mold, wherein the dimension correcting film portion composed of a plurality of atomic layers is formed by sequentially depositing layers . A basic mask material layer made of an inorganic material is formed on the first main surface portion of the substrate having the first main surface portion made of a plane via an intermediate film, and a convex shape is formed on the basic mask material layer. A first mask pattern forming step of patterning the first mask portion;
A basic mask pattern forming step of patterning a convex basic mask portion on the intermediate film by etching the basic mask material layer using the first mask portion as an etching mask and removing the first mask portion; ,
A dimension correcting film for forming a dimension correcting film part for correcting the dimension of the convex basic mask part so as to cover the side surface and upper surface of the convex basic mask part and the upper surface of the intermediate film. Part forming step;
Etch back the dimension correction film portion to expose the upper surface of the intermediate film; and
An intermediate film etching step of etching the intermediate film using an etching mask patterned on the intermediate film by the etch back step;
A substrate etching step of etching the first main surface portion of the substrate using an intermediate film mask patterned on the first main surface portion of the substrate by the intermediate film etching step;
In the dimension correcting film portion forming step, a first atomic layer is formed on the side surface and upper surface of the convex base mask portion and the upper surface of the intermediate film by an ALD method (atomic layer deposition method) at a predetermined temperature. depositing said predetermined and facilities annealed to atomic layer of the first layer at a temperature higher than the temperature, the predetermined ALD process at a temperature higher than the temperature (atomic layer deposition) by second and subsequent layers of atoms A method of manufacturing a nanoimprint mold, wherein the dimension correcting film portion composed of a plurality of atomic layers is formed by sequentially depositing layers .   The method for producing a nanoimprint mold according to claim 1, wherein the method of forming the convex basic mask portion in the basic mask pattern forming step is an electron beam (EB) lithography method, a photolithographic method, or a nanoimprint method.   3. The method for producing a nanoimprint mold according to claim 2, wherein a method of forming the convex first mask portion in the first mask pattern forming step is an electron beam (EB) lithography method, a photolithographic method, or a nanoimprint method. .   The convex first mask portion is made of a resist, and the method of forming the convex first mask portion in the first mask pattern forming step is an electron beam (EB) lithography method, a photolithographic method, or an in- The method for producing a nanoimprint mold according to claim 3, wherein the method is a printing method.

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