3D mold manufacturing method

Abstract

To provide a negative resist composition for gradation exposure capable of forming a three-dimensional pattern which is alkali-developable, is easy to control the height of convexity according to the amount of exposure light. is suitable for gradation exposure and has excellent resolution.SOLUTION: There is provided a method for manufacturing a three-dimensional mold which comprises; a step of applying a negative resist composition, which comprises a phenolic compound (A) having a molecular weight of 400 or more and 2500 or less and having 2 or more phenolic hydroxyl groups in one molecule and one or more kinds of 2 or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at an ortho position of the phenolic hydroxyl group in one molecule, substantially contains no acid generator and is a non-chemically amplified type in which the content of the phenolic compound (A) in the whole solid content of the negative resist composition is 70 wt.% or more, onto a substrate, followed by heat-treatment to form a resist film; and a step of subjecting the resist film to gradation exposure to develop.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a three-dimensional mold and a negative resist composition for gradational exposure. [Background technology]

[0002] In recent years, in the manufacture of semiconductor devices and display devices, advances in lithography technology have led to rapid progress in miniaturization of patterns, and high resolution is required. As a method for miniaturization, the wavelength of the exposure light source is generally shortened, and in addition to the currently used KrF excimer laser light, lithography using ArF, F2, EUV, X-rays, electron beams, and other charged particle beams as exposure light has been proposed.

[0003] Furthermore, alternative technologies to conventional lithography are being explored, such as nanoimprint lithography, which involves fabricating a mold using electron beam irradiation and then using the mold to transfer a nanometer-sized pattern onto a resin material on a substrate, thereby forming a fine concave-convex pattern. In nanoimprint lithography, the mold is the most important factor in determining the precision of the product. Therefore, a method for manufacturing a high-resolution mold, which serves as the original plate for nanoimprint lithography, is desired, as is the development of a high-resolution resist material that can be used to manufacture the mold.

[0004] Conventionally, microfabrication methods using electron beam irradiation have been mainly used to create two-dimensional patterns with the same height or depth, such as line and space, and there have been few examples of their application to the creation of three-dimensional mold patterns with varying heights, depths, line widths, etc. For example, Patent Document 1 discloses a method for manufacturing a three-dimensional mold, which includes an irradiation step of irradiating an electron beam onto a resist layer of a workpiece having a resist layer composed of organopolysiloxane on a base, and a development step of developing the resist layer after irradiating the electron beam to form uneven portions in the resist layer, wherein the irradiation step includes a step of irradiating with an acceleration voltage such that primary electrons do not reach the substrate and secondary electrons reach the substrate. However, the 3D mold manufacturing method of Patent Document 1 had the problem that, due to the low sensitivity of organopolysiloxane, a low acceleration voltage had to be used under the feasible exposure dose.Furthermore, the low acceleration voltage resulted in a deterioration of resolution performance, and only thin resists could be used.

[0005] As a resist material, for example, Patent Document 2 discloses a photoresist that crosslinks between polymer chains based on rearrangement of carbon-oxygen bonds in the pendant ester groups of a polymer such as poly(methoxyethoxyethyl methacrylate), with the aim of providing a negative tone photoresist that has high resolution, high sensitivity, can be developed in water or an aqueous solution, and is not chemically amplified. However, when such alkaline-developable and crosslinkable polymer materials are used, swelling easily occurs during development, and the molecular weight is large and the molecular weight distribution is broad, so there is a limit to how much the resolution can be reduced. Therefore, there is a need for further development of resist materials suitable for gradation exposure.

[0006] Therefore, low molecular weight materials have been developed as alkali-soluble resins that serve as resist substrates. The applicant has disclosed a negative resist composition that is capable of obtaining a chemically amplified or non-chemically amplified negative resist composition that has excellent line width stability after exposure in a vacuum, high resolution, and low line edge roughness patterns. The negative resist composition contains a phenolic compound (A) with a molecular weight of 400 to 2500, which has two or more phenolic hydroxyl groups per molecule and one or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions to the phenolic hydroxyl groups, and the content of the phenolic compound (A) is 70 mass% or more of the total solid content of the negative resist composition (Patent Document 3). However, Patent Document 3 does not describe at all performing gradation exposure or forming a concave-convex pattern having at least one of convex portions with different heights and convex portions with inclined surfaces. Furthermore, the basic compound described in Patent Document 3 is merely described as a quencher for suppressing the diffusion of acid generated from an acid generator in a chemically amplified negative resist composition. There is absolutely no description of combining a basic compound with a phenolic compound (A) without using an acid generator in a non-chemically amplified negative resist composition. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-293046 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-92135 [Patent Document 3] Patent No. 5083478 Summary of the Invention [Problem to be solved by the invention]

[0008] Resists for producing three-dimensional patterns require analog capabilities that allow the processing height (processing depth) to be controlled according to the exposure dose of, for example, electron beams, i.e., according to grayscale exposure. However, although conventional chemically amplified negative resist compositions are made highly sensitive by the addition of an acid generator, it is difficult to control the processing height according to the exposure dose, and they are not suitable for gradation exposure. Furthermore, conventional resist materials that allow easy control of processing height according to the exposure dose have low resolution.

[0009] In view of the above situation, a first object of the present disclosure is to provide a method for manufacturing, with high resolution, a three-dimensional mold having a concave-convex pattern shape that includes at least one of convex portions of different heights and convex portions with inclined surfaces. A second object of the present disclosure is to provide a negative resist composition for gradational exposure that allows alkaline development in pattern formation by irradiation with an electron beam, an ion beam, or EUV, is suitable for gradational exposure because the height of the convex portions can be easily controlled depending on the exposure dose, and is capable of forming a three-dimensional pattern with excellent resolution. [Means for solving the problem]

[0010] One embodiment of the present disclosure is a method for manufacturing a three-dimensional mold having a concave-convex pattern shape including at least one of convex portions having different heights and convex portions having inclined surfaces, the method comprising: a negative resist composition comprising a phenolic compound (A) having a molecular weight of 400 to 2500, the phenolic compound (A) having two or more phenolic hydroxyl groups per molecule and having two or more substituents per molecule, the substituents being one or more types selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups, at the ortho-positions of the phenolic hydroxyl groups, wherein the content of the phenolic compound (A) relative to the total solid content of the negative resist composition is 70 wt % or more; the negative resist composition is substantially free of an acid generator and is a non-chemically amplified type; and a step of applying the negative resist composition onto a substrate, followed by a heat treatment to form a resist film; The method for producing a three-dimensional mold includes steps of exposing the resist film to light and developing the light.

[0011] In the method for producing a three-dimensional mold according to the present disclosure, it is preferable that the negative resist composition further contains an organic basic compound (B), since this makes it easier to control the height of the convex portions with high precision in proportion to the amount of exposure light, thereby improving gradational exposure performance. In the method for producing a three-dimensional mold of the present disclosure, the organic basic compound (B) may be an organic basic compound containing a hydroxyl group.

[0012] In the method for manufacturing a three-dimensional mold of the present disclosure, the minimum distance between adjacent convex portions of the convex portions may be 500 nm or less.

[0013] Another embodiment of the present disclosure provides a negative resist composition for gradational exposure, which contains: a phenolic compound (A) having a molecular weight of 400 to 2500, which has two or more phenolic hydroxyl groups per molecule and has two or more substituents per molecule selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions to the phenolic hydroxyl groups; and an organic basic compound (B), wherein the content of the phenolic compound (A) relative to the total solids content of the negative resist composition is 70 wt % or more; and the negative resist composition is substantially free of an acid generator and is a non-chemically amplified type.

[0014] In the negative resist composition for gradational exposure according to the present disclosure, the organic basic compound (B) may be an organic basic compound containing a hydroxyl group. In the negative resist composition for gradational exposure according to the present disclosure, the organic basic compound (B) may have a molecular weight of less than 400. [Effects of the Invention]

[0015] According to the present disclosure, a method can be provided for manufacturing, with high resolution, a three-dimensional mold having a concave-convex pattern shape that includes at least one of convex portions of different heights and convex portions with inclined surfaces. Furthermore, according to the present disclosure, it is possible to provide a negative resist composition for gradational exposure that allows alkaline development in pattern formation by irradiation with an electron beam, an ion beam, or EUV, that makes it easy to control the height of the convex portions depending on the exposure dose, and that is capable of forming a three-dimensional pattern with excellent resolution. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view schematically illustrating an example of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a part of the EE' cross section of FIG. [Figure 3] FIG. 3 is a cross-sectional view that schematically shows a part of a cut surface of another example of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 5] FIG. 5 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 6] FIG. 6 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 7] FIG. 7 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 8] FIG. 8 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 9] FIG. 9 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 10] FIG. 10 is a cross-sectional view schematically showing an example of a convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 11] FIG. 11 is a cross-sectional view illustrating the radius of curvature R of the lower arc of the convex portion of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. [Figure 12]FIG. 12 shows the sensitivity curves of the exposure dose and the resist film thickness after development for the non-chemically amplified negative resist compositions of Production Examples 1 to 3. [Figure 13] FIG. 13 shows a scanning electron microscope photograph of a part of the cross section of the three-dimensional mold of Example 1. [Figure 14] FIG. 14 shows a scanning electron microscope photograph of a part of the cross section of the three-dimensional mold of Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments and examples of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments and examples exemplified below. Furthermore, to clarify the explanation, the drawings may schematically depict the width, thickness, shape, etc. of each part compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals, and detailed descriptions may be omitted as appropriate. Furthermore, for convenience of explanation, the terms "upper" and "lower" may be used in some cases, but the up-down direction may be reversed. In this specification, when a certain component, region, or other structure is said to be "on (or under)" another component, region, or other structure, unless otherwise specified, this includes not only the case where it is directly above (or directly below) the other structure, but also the case where it is above (or below) the other structure, i.e., the case where another component is included between the other structure and above (or below) the other structure.

[0018] In the present disclosure, "active energy rays" refers to far ultraviolet rays such as KrF excimer laser, ArF excimer laser, and F2 excimer laser, electron beams, ion beams, EUV, X-rays, and the like. In the description of groups (atomic groups) in this disclosure, when a notation does not specify whether they are substituted or unsubstituted, it encompasses both unsubstituted and substituted groups. For example, an "alkyl group" encompasses not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). The divalent bonds of an alkylene group include divalent bonds from the same carbon atom (e.g., -CH2CH2-) as well as bonds from different carbon atoms (e.g., -CH2-). Furthermore, alkyl groups and cycloalkyl groups include saturated hydrocarbons as well as unsaturated hydrocarbons with double bonds, triple bonds, etc. Cycloalkyl groups include monocyclic as well as polycyclic hydrocarbons such as bicyclic and tricyclic. In the present disclosure, the term "phenolic hydroxyl group" refers to a hydroxyl group directly bonded to an aromatic ring such as benzene. In the present disclosure, the phrase "at least one of X and Y" means "(X), (Y), or (X and Y)." Furthermore, in the present disclosure, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower limit and upper limit. The method for producing a three-dimensional mold and the negative resist composition for gradational exposure according to the present disclosure will be described in detail below.

[0019] I. 3D mold manufacturing method A method for manufacturing a three-dimensional mold according to one embodiment of the present disclosure is a method for manufacturing a three-dimensional mold having a concave-convex pattern shape including at least one of convex portions having different heights and convex portions having inclined surfaces, the method comprising: a negative resist composition comprising a phenolic compound (A) having a molecular weight of 400 to 2500, the phenolic compound (A) having two or more phenolic hydroxyl groups per molecule and having two or more substituents per molecule, the substituents being one or more types selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups, at the ortho-positions of the phenolic hydroxyl groups, wherein the content of the phenolic compound (A) relative to the total solid content of the negative resist composition is 70 wt % or more; the negative resist composition is substantially free of an acid generator and is a non-chemically amplified type; and a step of applying the negative resist composition onto a substrate, followed by a heat treatment to form a resist film; and a step of exposing the resist film to light and developing the light.

[0020] In the method for producing a three-dimensional mold according to one embodiment of the present disclosure, a resist film is produced using the specific non-chemically amplified negative resist composition, and then subjected to gradational exposure, thereby enabling the production of a three-dimensional mold with a concave-convex pattern shape having at least one of convex portions of different heights and convex portions having inclined surfaces, at high resolution. In the method for manufacturing a three-dimensional mold according to one embodiment of the present disclosure, the height of the convex portions can be controlled with high precision in proportion to the amount of exposure light, making it possible to manufacture a three-dimensional mold with a desired uneven pattern having convex portions of different heights and convex portions with inclined surfaces with high precision. The specific non-chemically amplified negative resist composition has a relatively gentle slope γ in the sensitivity curve (contrast curve) of the exposure dose and the resist film thickness after development, making it easy to control the height of the convex portions depending on the exposure dose, and the resist film is less likely to swell during development. It also has a relatively small molecular weight and a narrow molecular weight distribution, and is therefore presumably capable of forming a highly accurate and high-resolution concave-convex pattern.

[0021] The method for producing such a three-dimensional mold according to the present disclosure will be described in detail below. 1. 3D mold The three-dimensional mold produced by the production method of the present disclosure has a concave-convex pattern shape that includes at least one of convex portions with different heights and convex portions with inclined surfaces. The three-dimensional mold manufactured by the manufacturing method of the present disclosure will be described with reference to the drawings. Fig. 1 is a perspective view schematically showing an example of a three-dimensional mold manufactured by the manufacturing method of the present disclosure, and Fig. 2 is a cross-sectional view schematically showing a part of the E-E' cross section of Fig. 1. The three-dimensional mold 100 shown in FIG. 1 of the present disclosure includes a concave-convex pattern layer 10 having a concave-convex pattern shape 3 in which a plurality of linear convex portions 1 having inclined surfaces extend parallel to one another in a common direction Y.

[0022] In this disclosure, the cross-sectional shape of a three-dimensional mold is defined as if the three-dimensional mold were placed on a horizontal plane. In the example of FIG. 1, the X axis is taken in the direction of repetition of the periodic structure, the Y axis is taken perpendicular to the X axis so that XY forms a horizontal plane, and the Z axis is taken in a direction perpendicular to the XY horizontal plane. As shown in FIG. 2, in this disclosure, the valley bottom between convex portions (the minimum point of Z) is used as the reference for height 0, and the portion with height 0 is referred to as recess 2. In this disclosure, the portion with height H (H > 0) is referred to as convex portion 1. Meanwhile, in this disclosure, the maximum height of the convex portions is used as the reference and the depth is sometimes referred to as the valley bottom between convex portions. However, in this disclosure, height and depth are in a front-back relationship, and when focusing on convex portions, height is used, and when focusing on recessed portions, depth is used, and they are essentially the same thing. Therefore, if there are multiple valley bottoms (minimum points of Z) between convex portions with different Z values, the convex portions with different heights can also be said to have concave portions with different depths (see, for example, Figure 10 described below). 2, the distance from one end 5 of a certain convex portion to one end 5' of an adjacent convex portion on the same side is defined as the distance (pitch) P between adjacent convex portions 1. The end of a convex portion refers to the portion that begins to have a height H (H>0) from the valley bottom (minimum point of Z) between the convex portions. The distances (pitch) between the convex portions may be the same or different, or may have a predetermined repeating period.

[0023] The three-dimensional mold manufactured by the manufacturing method of the present disclosure may have other configurations in addition to the concave-convex pattern layer having a concave-convex pattern shape. For example, the three-dimensional mold manufactured by the manufacturing method of the present disclosure may have a concave-convex pattern layer formed on a substrate. Furthermore, the three-dimensional mold manufactured by the manufacturing method of the present disclosure may have a concave-convex pattern layer 10 formed on a substrate 20 via an adhesive layer 30, as shown in FIG.

[0024] (1) Concave and convex pattern shape The concave-convex pattern shape of the three-dimensional mold produced by the production method of the present disclosure includes at least one of convex portions of different heights and convex portions having inclined surfaces. In the present disclosure, having convex portions of different heights may mean that a single convex portion has a convex portion whose height changes in several steps (multi-step structure convex portion), or that convex portions whose heights are different from each other (multi-value structure convex portion), or that convex portions whose heights are different from each other (multi-value structure convex portion) have a multi-step structure convex portion. In addition, in the present disclosure, a convex portion having an inclined surface can be said to be one form of a convex portion whose height varies within one convex portion.

[0025] 4 and 5 show examples of a convex portion whose height changes in several steps (a multi-step structure convex portion). In the present disclosure, a convex portion having two or more flat portions (approximately horizontal portions) in a cross-sectional shape is sometimes referred to as a multi-step shape, and when the convex portion and the concave portion of the multi-step shape have n flat portions in total, it is sometimes referred to as an n-level shape. The example in FIG. 4 is a three-step shape, and the example in FIG. 5 is a five-step shape. Although not shown, in the case of a conventional line-and-space cross-sectional shape that can be manufactured without gradation exposure, the flat portion of the convex portion and the flat portion of the concave portion combine to form a two-step shape. However, since the height of the convex portion is constant, there are no slopes, and the reference value of the concave portion is constant, this does not fall under the case of having at least one of convex portions of different heights and convex portions having slopes as disclosed in the present disclosure.

[0026] FIG. 6 shows an example of a convex portion having an inclined surface. The convex portion in FIG. 2 also corresponds to an example of a convex portion having an inclined surface. In the present disclosure, an inclined surface refers to a surface that is neither perpendicular nor horizontal to the XY horizontal plane, and may have a curved surface. In the present disclosure, the inclination angle of the convex portion having an inclined surface may be, for example, 88 degrees or less, 85 degrees or less, 70 degrees or less, or 15 degrees to 60 degrees, or 45 degrees or less, relative to the XY horizontal plane. Examples of the cross-sectional shape of the convex portion having an inclined surface include a triangular shape as shown in FIG. 2, a substantially triangular shape as shown in FIG. 6, a rectangular shape with an inclined surface (not shown), a partially curved trapezoid, a parabolic shape, a bell shape, a semicircular shape, and a semi-elliptical shape. In the present invention, when the cross-sectional shape of a convex portion having an inclined surface is triangular as shown in FIG. 2 or approximately triangular as shown in FIG. 6, it is possible to form the apex angle to be more acute than in the past. Whereas the apex angle was previously an obtuse angle of about 120 degrees, it is now possible to form convex portions having inclined surfaces with a triangular or approximately triangular cross-sectional shape, where the apex angle is an acute angle of less than 90 degrees or 80 degrees or less.

[0027] 7 to 10 show examples in which convex portions (multi-level structure convex portions) of different heights are provided. FIG. 8 shows an example in which convex portions (multi-level structure convex portions) of different heights are provided with multi-step structure convex portions. FIG. 9 shows an example in which convex portions (multi-level structure convex portions) of different heights are provided with convex portions having inclined surfaces. The convex portions of different heights may or may not have a predetermined repeating period.

[0028] According to the manufacturing method of the present disclosure, a three-dimensional mold can be manufactured with high resolution, and therefore, for example, a three-dimensional mold can be manufactured in which the minimum distance between adjacent convex portions is 500 nm or less. The minimum spacing between adjacent convex portions may be appropriately selected according to the intended use of the concave-convex pattern of the three-dimensional mold, and is not particularly limited, but may be 400 nm or less, 350 nm or less, or 300 nm or less.

[0029] Furthermore, the aspect ratio, defined as the height of a convex portion relative to the spacing P between adjacent convex portions ((height H of a convex portion) / (spacing P between adjacent convex portions)), may be appropriately selected according to the intended use of the concave-convex pattern of the three-dimensional mold, and is not particularly limited, but may be 5 or less, or 2 or less, from the perspective of further etching the three-dimensional mold. On the other hand, from the perspective of using the three-dimensional mold as a mold as is, the aspect ratio may be 0.25 or more. In the present disclosure, when the heights of the two ends of a convex portion are different as in FIG. 10, the maximum height is adopted as the height H of the convex portion.

[0030] Furthermore, according to the manufacturing method of the present disclosure, the height of the convex portions can be controlled with high precision in proportion to the amount of exposure light, making it easy to achieve a desired concave-convex pattern shape. Conventionally, when gradation exposure is performed using a negative resist composition, it has been difficult to form a slope or control the shape of a portion with a relatively low exposure dose. For example, as shown in Figure 11(A), when forming a pattern with a triangular cross section as an ideal structure, the height of the convex portion is controlled in proportion to the amount of exposure 40. However, in the past, as shown in Figure 11(B), a portion with a low exposure dose adjacent to a portion with a relatively high exposure dose is affected by the portion with a high exposure dose, making it impossible to form a desired slope, and the lower part (rising portion) of the convex portion becomes rounded. As shown in FIG. 11(B), the roundness of the lower portion (rising portion) of the convex portion can be expressed using the radius of curvature R of the arc at the rounded lower portion of the convex portion and the height H of the convex portion. The radius of curvature R of the arc can be calculated by approximating a circle from two coordinates of the arc. The radius of curvature R of the arc can be calculated by referring to Japanese Patent Application Laid-Open No. 2004-125690. First, two initial straight lines are fitted from the vicinity of both ends of the sequence of points, and then an initial arc is fitted to the remaining sequence of points far from the initial two straight lines. The radius of curvature R of the arc can be calculated by repeating the line-arc-line fitting process. According to the manufacturing method disclosed herein, the radius of curvature of the arc of the lower portion of the convex portion can be set to 50% or less of the height H of the convex portion. To approximate an ideal structure, the radius of curvature of the arc of the lower portion of the convex portion may be 40% or less, 30% or less, or 25% or less of the height H of the convex portion.

[0031] In the present disclosure, the spacing P between adjacent convex portions, the height H of the convex portions, the width W of the convex portions, the radius of curvature R of the arc, etc. can be measured from images of the cross section of a three-dimensional mold taken with an atomic force microscope (AFM) or a scanning electron microscope (SEM). To find the minimum adjacent convex portion spacing, if the adjacent convex portion spacing P is approximately constant, the number of adjacent convex portion spacings P to be found may be small, but if the adjacent convex portion spacing P changes periodically, it is preferable to find at least five periods, and if the adjacent convex portion spacing P changes without periodicity, it is preferable to find more adjacent convex portion spacings P.

[0032] The concave-convex pattern shape of the three-dimensional mold manufactured by the manufacturing method of the present disclosure is not particularly limited, and can be implemented in many different forms, as long as it has convex portions of different heights formed using gradational exposure and convex portions with inclined surfaces. The concave-convex pattern shape of the three-dimensional mold produced by the production method of the present disclosure does not need to have a periodic structure, and even if it does have a periodic structure, it may have multiple regions with different periodic structures. For example, the multiple partially periodic structure regions may each have convex portions with different shapes, heights, and adjacent convex portion intervals.

[0033] (2) Textured pattern layer The concave-convex pattern layer 10 having the concave-convex pattern shape 3 is made of a cured product of the specific negative resist composition. The specific negative resist composition will be described in detail later, so a description thereof will be omitted here. The concave-convex pattern layer having a concave-convex pattern shape may not be connected at the lower parts of the convex portions, i.e., the concave-convex pattern layer may be composed of a group of convex portions, with no cured product of the specific negative resist composition present in the concave portions of the concave-convex pattern.

[0034] The thickness of the concave-convex pattern layer 10 is not particularly limited, and may be adjusted appropriately depending on the concave-convex pattern shape according to the intended use of the three-dimensional mold. The thickness of the concave-convex pattern layer 10 may be, for example, 50 nm to 500 nm, and may further be 500 nm to 2000 nm.

[0035] (3) Circuit board Substrates for use in the three-dimensional molds manufactured by the manufacturing method of the present disclosure include, but are not limited to, quartz, glass, optical films, ceramic materials, vapor deposition films, magnetic films, reflective films, metal substrates such as Ni, Cu, Cr, and Fe, paper, spin-on glass (SOG), polymer substrates such as polyester films, polycarbonate films, and polyimide films, TFT array substrates, PDP electrode plates, glass and transparent plastic substrates, conductive substrates such as ITO and metals, insulating substrates, and semiconductor substrates such as silicone, silicone nitride, polysilicone, silicone oxide, and amorphous silicone. Suitable photomask substrates include transparent quartz glass substrates having a light-shielding layer or low-reflection layer such as CrxOyNz, MoSi, MoSiO, MoSiON, TaSiO, TaBO, or TaBN. The thickness of the substrate is not particularly limited and may be appropriately selected depending on the application. The thickness of the substrate 20 may be, for example, 0.1 mm to 1 mm, or may be 1 mm to 10 mm.

[0036] (4) Adhesion layer The substrate used in the three-dimensional mold produced by the production method of the present disclosure may have an adhesion layer that has been surface-treated with an adhesion agent or the like on the substrate in order to improve adhesion between the specific negative resist composition or its cured product and the substrate. Examples of adhesives used in the adhesive layer include hexamethyldisilazane, silane coupling agents, acid anhydrides, and phosphate esters. In particular, those having a functional group that can react with the ethylenically unsaturated bond of the resin composition are preferred. Examples include vinyltrimethoxysilane (trade name KBM-1003, Shin-Etsu Chemical Co., Ltd.), 3-acryloxypropyltrimethoxysilane (trade name KBM-5103, Shin-Etsu Chemical Co., Ltd.), p-styryltrimethoxysilane (trade name KBM-1403, Shin-Etsu Chemical Co., Ltd.), ACRYLOXYMETHYLTRIMETHOXYSILANE (trade name SIA0182.0, Gelest), β-carboxyethyl acrylate (trade name β-CEA, UCB Chemical), Ebecryl 3605 (UCB Chemical), Isorad 501 (Schenectady International, Inc.), and compositions 1 to 5 disclosed in JP 2009-503139 A. The thickness of the adhesive layer 30 may be appropriately selected depending on the application and is not particularly limited, but may be, for example, 10 nm to 100 nm, or 100 nm to 2000 nm. The three-dimensional mold manufactured by the manufacturing method of the present disclosure may further have other configurations.

[0037] 2. Process of forming a resist film The method for producing a three-dimensional mold of the present disclosure includes a step of applying a negative resist composition that contains a phenolic compound (A) with a molecular weight of 400 to 2500, which has two or more phenolic hydroxyl groups in one molecule and has two or more substituents in one molecule selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions of the phenolic hydroxyl groups, wherein the content of the phenolic compound (A) in the total solid content of the negative resist composition is 70 wt % or more, and which is a non-chemically amplified negative resist composition that is substantially free of an acid generator, onto a substrate, followed by a heat treatment to form a resist film.

[0038] (1) Negative resist composition The specific phenolic compound (A) is a relatively low-molecular-weight specific phenolic compound serving as a resist substrate, to which one or more crosslinking groups selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group are introduced at the ortho-position of the phenolic hydroxyl group, i.e., the specific phenolic compound (A) is a resist substrate that also functions as a crosslinker. The specific phenolic compound (A) has a high ratio of crosslinkable groups to hydroxyl groups, and the content of the phenolic compound (A) relative to the total solids content in the resist composition is high. Therefore, in the non-chemically amplified negative resist composition of the present disclosure, a crosslinking reaction by the crosslinkable groups of the specific phenolic compound (A) proceeds without the intervention of an acid when irradiated with active energy rays. The negative resist composition is alkali-soluble due to the presence of a phenolic hydroxyl group, but upon exposure (irradiation with light) to an electron beam or the like during resist pattern formation, the phenolic compounds (A) form crosslinks with each other due to the presence of one or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups present at the ortho-position of the phenolic hydroxyl group, rendering the composition alkali-insoluble. Therefore, when a resist film made from the negative resist composition is selectively exposed during resist pattern formation, the exposed areas become alkali-insoluble, while the unexposed areas remain alkali-soluble, and therefore a negative resist pattern can be formed by alkali development. Furthermore, the non-chemically amplified negative resist composition of the present disclosure uses the specific phenolic compound (A), which has a relatively low molecular weight, in a state in which the solids content of the resist composition is high, which results in good uniformity of the resist composition in the coating film.Furthermore, because the resist composition does not utilize the diffusion of acid during image formation, it is easy to control the height of the convex portions in accordance with the exposure dose, and it is presumed that the resist composition will have excellent gradation exposure performance and also excellent resolving power.

[0039] Below, each component of the negative resist composition of the present disclosure will be described in detail. <Phenol Compound (A)> The phenolic compound (A) used in the present disclosure is a compound having two or more phenolic hydroxyl groups in one molecule, and having two or more substituents in one molecule selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions of the phenolic hydroxyl groups, and a molecular weight of 400 to 2500. By setting the molecular weight of the phenolic compound (A) within the above range, excellent resolution can be obtained.

[0040] The phenolic compound (A) used in the present disclosure may have two or more phenolic hydroxyl groups in one molecule, and the number of phenolic hydroxyl groups in one molecule is not particularly limited. The phenolic compound (A) used in the present disclosure is preferably selected appropriately so as to have alkali solubility based on the following criteria. The phenolic compound (A) is preferably selected from those having a development rate of 0.5 nm / sec or higher in a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (23°C), more preferably 1.0 nm / sec or higher. By adjusting the alkali development rate of the alkali-soluble resin within the above range, the pattern shape can be improved.

[0041] For example, the development rate in a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (23°C) can be calculated by, for example, using the phenolic compound (A) alone to prepare, for example, a 5% by mass solution, forming a coating film on a silicon wafer so that the film thickness after drying is 300 nm, immersing the wafer in a 25% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) (23°C), and measuring the time until the coating film is completely dissolved.

[0042] The phenolic compound (A) used in the present disclosure may have two or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-position of the phenolic hydroxyl group per molecule. The one or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-position of the phenolic hydroxyl group function as crosslinkable groups of the phenolic compound. From the viewpoint of enhancing crosslinkability, the phenolic compound (A) used in the present disclosure preferably has three or more, and even four or more, substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-position of the phenolic hydroxyl group per molecule.

[0043] The alkoxymethyl group is preferably one having 1 to 6 carbon atoms, and specific examples thereof include a methoxymethyl group, an ethoxymethyl group, an n-propoxymethyl group, an isopropoxymethyl group, an n-butoxymethyl group, a sec-butoxymethyl group, a t-butoxymethyl group, various pentyloxymethyl groups, etc. Of these, the alkoxymethyl group is preferably a methoxymethyl group or an ethoxymethyl group in view of improving sensitivity.

[0044] As the crosslinkable group, one or more substituents selected from the group consisting of a hydroxymethyl group, a methoxymethyl group, and an ethoxymethyl group are preferably placed at the ortho position of the phenolic hydroxyl group, as this provides high reactivity and good sensitivity.

[0045] The phenolic compound (A) used in the present disclosure is selected to have a molecular weight of 400 to 2500. If the molecular weight is below the lower limit, the ability to form a resist film and the ability to form a pattern may be impaired. On the other hand, if the molecular weight exceeds the upper limit, the resist composition may be easily swollen by the solvent used in the resist composition, which may cause pattern collapse and poor pattern shape. Here, the molecular weight refers to the sum of the atomic weights of the atoms constituting the molecule. In addition, in the case of an oligomer having a molecular weight distribution, the molecular weight is expressed as the mass average molecular weight using GPC (polystyrene equivalent). The molecular weight of the phenolic compound (A) used in the present disclosure is preferably 500 to 2500, and more preferably 600 to 2000 from the viewpoints of film-forming properties and resolution.

[0046] The phenolic compound (A) used in the present disclosure preferably has a glass transition temperature (Tg) of 60°C or higher, more preferably 90°C or higher. If the glass transition temperature is 60°C or higher, dewetting is less likely to occur when forming a coating film, making it easier to obtain a uniform film. Note that dewetting refers to a phenomenon in which a spread coating film dissolves during pre-baking, causing repellency and resulting in an inconsistent film formation. Typically, solvents with a boiling point of 90 to 180°C are used as solvents for resist compositions because the resist film dries too quickly and a uniform film cannot be obtained. Therefore, to obtain a uniform resist film when applied by a method such as spin coating, solvents with a boiling point of 90 to 180°C are used. Resist films formed by spin coating contain a large amount of residual solvent, so to remove this solvent and form a stable resist film, the resist substrate is heated on a hot plate at a temperature of 90°C or higher (pre-baking). However, if a phenolic compound with a glass transition temperature of less than 60°C is used, the resist film may dewet during the pre-baking process, potentially preventing the formation of a uniform film. In contrast, when a phenolic compound with a glass transition temperature of 60°C or higher is used, pre-baking at high temperatures becomes possible, resulting in a uniform film and a resist film with excellent environmental resistance (post-coating delay: PCD). Furthermore, the pattern density dependency that occurs during pattern formation using an electron beam can be suppressed. Furthermore, in the dry etching process after resist pattern formation, a pattern with excellent etching resistance (which can prevent the pattern from melting due to high temperatures during etching) can be obtained. The glass transition temperature here is measured by a differential scanning calorimeter (DSC).

[0047] Furthermore, the phenolic compound (A) used in the present disclosure preferably has a solubility of 5% by mass or more at 23°C in an organic solvent having a boiling point of 80 to 180°C. In such a case, it is possible to prevent the resist film from drying out rapidly during spin coating, which has the advantage of allowing for the production of a uniform resist film. Representative examples of organic solvents having a boiling point of 80 to 180°C include cyclopentanone, propylene glycol monomethyl ether, cyclohexanone, propylene glycol monomethyl ether acetate, ethyl lactate, 2-heptanone, diethylene glycol dimethyl ether, and 1-ethoxy-2-propanol.

[0048] In particular, the phenolic compound (A) used in the present disclosure preferably has a glass transition temperature (Tg) of 60°C or higher and a solubility of 5% by mass or higher at 23°C in organic solvents having a boiling point of 80 to 180°C.

[0049] The phenolic compound (A) is not particularly limited and may be appropriately selected and used, and examples thereof include compounds represented by the following chemical formulas (1) and (3).

[0050] [ka] [In chemical formula (1), R 1 are each independently a group selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, and a group represented by the following chemical formula (2), and R 1 The aryl group contained in may contain one or more substituents selected from the group consisting of a hydroxyl group, a hydroxymethyl group, and an alkoxymethyl group.

[0051] [ka] (In chemical formula (2), R 4 and R 5are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, Q is an aryl group or a cycloalkyl group, and m is 1 or 2. R 2 are each independently a hydrogen atom or a monovalent organic group, and a plurality of R 2 At least two of the R atoms in each molecule are hydrogen atoms. 3 is a group selected from the group consisting of a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an acyl group, a cyano group, a nitro group, a hydroxymethyl group, and an alkoxymethyl group. n1 represents an integer of 1 to 3, and n2 represents an integer of 0 to 2. However, a combination of n1 and n2 that satisfies n1+n2≦4 is selected from the numerical ranges of n1 and n2. x1 represents an integer of 3 to 12. However, R 1 and / or R 3 In the formula (I), one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group are present at the ortho-position of the phenolic hydroxyl group in one molecule. In addition, groups represented by the same symbol in chemical formula (1) may be the same or different from each other.]

[0052] [ka] (In chemical formula (3), R 6 , R 7 , R 8 and R 9 Each of R independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a hydroxymethyl group, an alkoxymethyl group, or a group consisting of a combination thereof. 6 may be bonded to form a ring. 7 may be bonded to form a ring. 8 may be bonded to form a ring. 9 may be bonded to form a ring. 6 , R 7 , R 8 and R 9may be the same or different from each other. R 10 and R 11 each independently represents a hydrogen atom or a monovalent organic group, and a plurality of R 10 and R 11 may be the same or different. 10 and R 11 At least two of R are hydrogen atoms. 6 , R 7 , and / or R 9 In the formula (I), one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group are present at the ortho-position of the phenolic hydroxyl group in one molecule. W represents a single bond, an ether bond, a thioether bond, an alkylene group, a cycloalkylene group, or an arylene group which may contain a heteroatom, or a group consisting of any combination thereof. Multiple Ws may be the same or different. x2 represents a positive integer. y1 represents an integer of 0 or more, and when W is a single bond, y1 is 0. y2 represents an integer greater than or equal to 0, and y3 represents a positive integer. z represents an integer of 0 or greater. v represents an integer of 0 or greater. k1 and k4 represent positive integers. k2, k3, and k5 each independently represent an integer of 0 or greater, provided that k1+k2+z=5, k3+v=3, k4+k5=5, and k2+k5≧2 are satisfied.

[0053] In the compound represented by the above chemical formula (1), R 1 The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms. The alkyl group may be linear or branched. Examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an i-propyl group, an i-butyl group, a t-butyl group, an i-pentyl group, a t-pentyl group, and a hexadecyl group. The alkyl group may also have an unsaturated bond such as a double bond or a triple bond.

[0054] Examples of the substituent that the alkyl group may have include a hydroxyl group, an alkoxy group, a halogen atom, and a halogenoalkyl group.

[0055] R 1 The cycloalkyl group is not particularly limited, and examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, etc. Furthermore, the cycloalkyl group may have an unsaturated bond such as a double bond or a triple bond, and may be either monocyclic or polycyclic. The cycloalkyl group is preferably a cyclohexyl group.

[0056] The substituent on the cycloalkyl group is not particularly limited, and examples thereof include an alkyl group having 1 to 5 carbon atoms, a hydroxyl group, an alkoxy group, an alkoxyalkyl group, a halogen atom, and a halogenoalkyl group.

[0057] The alkyl group having 1 to 5 carbon atoms may be either linear or branched. Examples of linear alkyl groups include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. Examples of branched alkyl groups include an i-propyl group, an i-butyl group, a t-butyl group, an i-pentyl group, and an t-pentyl group.

[0058] The alkoxy group is not particularly limited, but is preferably an alkoxy group having 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 2-ethylhexyloxy group.

[0059] The alkoxyalkyl group is not particularly limited, but is preferably an alkoxyalkyl group having 1 to 8 carbon atoms, and examples thereof include a methoxymethyl group, an ethoxymethyl group, a methoxyethyl group, an ethoxyethyl group, and a methoxypropyl group.

[0060] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0061] The halogenoalkyl group is not particularly limited, but is preferably a halogenoalkyl group having 1 to 8 carbon atoms, and examples thereof include a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 1-chloroethyl group, a 1-bromoethyl group, a 1-fluoroethyl group, a 1,2-dichloroethyl group, and a 1,1,2,2-tetrachloroethyl group.

[0062] R 1 The aryl group is not particularly limited, but preferably has 6 to 14 carbon atoms, more preferably 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.

[0063] In addition, examples of the substituent on the aryl group include a hydroxymethyl group, an alkoxymethyl group, a cycloalkyl group, an alkyl group having 1 to 5 carbon atoms, a hydroxyl group, an alkoxy group, an alkoxyalkyl group, a halogen atom, and a halogenoalkyl group. Examples of the cycloalkyl group as a substituent on the aryl group include the same as the above-mentioned cycloalkyl group. The cycloalkyl group may have a substituent, and examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a halogen atom, a cyano group, a hydroxyl group, an alkoxy group, etc. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an i-propyl group, etc. The alkoxy group is not particularly limited, but is preferably an alkoxy group having 1 to 8 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a 2-ethylhexyloxy group. The alkyl group, alkoxy group, alkoxyalkyl group, halogen atom, halogenoalkyl group, and alkoxymethyl group having 1 to 5 carbon atoms as the substituent on the aryl group are as defined above.

[0064] In the above chemical formula (2), R 4 and R 5are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. The alkyl group having 1 to 3 carbon atoms may be either linear or branched, and among these, a methyl group and an ethyl group are preferred from the viewpoint of etching resistance. When m is 2, two R 4 and R 5 may be the same or different. In the above chemical formula (2), R 4 and R 5 and R 1 and R 2 are preferably hydrogen atoms.

[0065] The aryl group of Q in the above chemical formula (2) includes the same as the aryl group described above. The substituents of the aryl group of Q include the same as the substituents of the aryl group described above, and may include one or more substituents selected from the group consisting of a hydroxyl group, a hydroxymethyl group, and an alkoxymethyl group. Furthermore, the cycloalkyl group of Q in the above chemical formula (2) includes the same as the cycloalkyl group described above. The substituents of the cycloalkyl group of Q include the same as the substituents of the cycloalkyl group described above.

[0066] R 2 The monovalent organic group is not particularly limited, but may be an alkyl group, a cycloalkyl group, an aryl group, or an alkyl group. Examples of such groups include aryl groups. R 2 The alkyl group of the above R 1 Similar examples include R 2 The substituents of the alkyl group in the above R 1 Examples include those similar to those in the above. Also, R 2 The cycloalkyl group and the substituents of the cycloalkyl group include the above R 1 Furthermore, R 2 The aryl group and the substituents of the aryl group include the above-mentioned R 1 The same can be used.

[0067] R 3The alkoxymethyl group is as defined above. R 3 The halogen atom and alkyl group of the above R 1 The same can be mentioned. R 3 Examples of the substituent that the alkyl group has as the substituent include a cycloalkyl group, an aryl group, an amino group, an amido group, a ureido group, a urethane group, a hydroxyl group, a carboxy group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group, and a nitro group.

[0068] R 3 The cycloalkyl group and the substituents of the cycloalkyl group include the above R 1 It can be similar to that of R 3 The aryl group and the substituents of the aryl group include the above-mentioned R 1 The same can be used. Also, R 3 The alkoxy group in the above R 1 The same can be mentioned.

[0069] R 3 The acyl group is not particularly limited, but is preferably an acyl group having 1 to 8 carbon atoms, and examples thereof include a formyl group, an acetyl group, a propionyl group, a butyryl group, a valeryl group, a pivaloyl group, and a benzoyl group.

[0070] x1 is an integer of 3 to 12, preferably an integer of 4 to 12, and more preferably an integer of 4 to 8.

[0071] The compound represented by the chemical formula (1) has two or more phenolic hydroxyl groups in one molecule, and one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho-position of the phenolic hydroxyl group, and the substituents represented by the same symbol in each repeating unit may be the same or different. 2 and R 3 The positions may be the same or different.

[0072] In the compound represented by the above chemical formula (1), in order to obtain a pattern with high sensitivity, high resolution, and good shape, it is particularly preferable that x1 is 4 and n1 is 2, and more preferably, x1 is 4, n1 is 2, and 8 R 2 A calixresorcinarene derivative having 4 to 8 hydrogen atoms, and R 2 Preferably, each molecule has at least one substituent selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho-position where the hydrogen atom is present. In addition, in the compound represented by the above chemical formula (1), from the viewpoint of obtaining a pattern with high sensitivity, high resolution, and good shape, it is particularly preferable that x1 is 4 and n1 is 2, and more preferably, x1 is 4 and n1 is 2, and the compound having eight R 2 A calixresorcinarene derivative having 0 to 8 hydrogen atoms, and R 1 In addition, it preferably has a phenolic hydroxyl group and an aryl group containing one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group.

[0073] On the other hand, in the compound represented by the above chemical formula (3), R 6 , R 7 , R 8 and R 9 The alkyl group in the formula (I) may be linear or branched, and preferred examples include those having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, isobutyl, hexyl, and octyl groups. R 6 , R 7 , R 8 and R 9The cycloalkyl group in may be either monocyclic or polycyclic. Examples include groups having a monocyclo, bicyclo, tricyclo, or tetracyclo structure having 5 or more carbon atoms. The number of carbon atoms is preferably 6 to 30, and particularly preferably 7 to 25, and examples thereof include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group. These alicyclic hydrocarbon groups may have a substituent. R 6 , R 7 , R 8 and R 9 The aryl group in the above R 1 It may be the same as: Also, R 6 , R 7 , R 8 and R 9 The hydroxymethyl group or alkoxymethyl group in may be the same as above. In the compound represented by the above chemical formula (3), R 6 If (x2) is an integer greater than or equal to 2, the group is (x2)-valent.

[0074] Examples of the substituent that the alkyl group, cycloalkyl group, and aryl group may have include a hydroxyl group, a carboxyl group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an alkoxy group (a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc.), a hydroxymethyl group, and an alkoxymethyl group.

[0075] R 10 and R 11Examples of the monovalent organic group in the formula (I) include an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an alkoxycarbonyl group, an amide group, and a cyano group. The alkyl group is preferably an alkyl group or a cycloalkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, and an adamantyl group. The aryl group is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a naphthyl group, and an anthracenyl group. The aralkyl group is preferably an aralkyl group having 6 to 12 carbon atoms, such as a benzyl group, a phenethyl group, and a cumyl group. The alkoxy group in the alkoxycarbonyl group is preferably an alkoxy group having 1 to 5 carbon atoms, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, and an isobutoxy group.

[0076] The alkylene group in W may be linear or branched, and preferably has 1 to 10 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, or an isobutylene group. The cycloalkylene group for W may be either monocyclic or polycyclic, and examples of the alkylene group forming the ring include cycloalkylene groups having 3 to 8 carbon atoms (for example, cyclopentylene and cyclohexylene). The alkylene group and cycloalkylene group for W may further have a substituent, and examples of the substituent include an alkyl group (preferably having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group), an alkoxy group (preferably having 1 to 4 carbon atoms, for example, a methoxy group, an ethoxy group, a propoxy group, and a butoxy group), a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0077] The alkylene chain or cycloalkylene chain may contain -O-, -OC(=O)-, -OC(=O)O-, -N(R)-C(=O)-, -N(R)-C(=O)O-, -S-, -SO-, or -SO2- in the alkylene chain, where R is a hydrogen atom or an alkyl group (preferably having 1 to 10 carbon atoms, such as a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, or decyl group). The cyclic arylene group for W is preferably one having 6 to 15 carbon atoms, such as a phenylene group, a tolylene group, or a naphthylene group.

[0078] Specific examples of the phenolic compound (A) are shown below, but the present disclosure is not limited to these. As long as there are two or more phenolic hydroxyl groups in one molecule and two or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions of the phenolic hydroxyl groups in one molecule, the phenolic hydroxyl groups in the following specific examples may be protected with an organic group. In the following formula, each L is independently a hydrogen atom or one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group, and at least two Ls in one molecule are one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group located at the ortho-position of the phenolic hydroxyl group. The molecular weight is 400 to 2500.

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] The phenolic compound (A) used in the present disclosure can be obtained by introducing one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group into the ortho-position of the phenolic hydroxyl group in the mother compound of the phenolic compound. The above-mentioned substituents functioning as crosslinkable groups can be introduced into the mother compound of the phenolic compound, for example, by reacting a phenolic compound lacking the corresponding hydroxymethyl group with formaldehyde in the presence of a base catalyst. In this case, the reaction temperature is preferably 50°C or less to prevent side reactions such as gelation. Furthermore, various bisphenol derivatives having an alkoxymethyl group can be obtained by reacting a bisphenol derivative having the corresponding hydroxymethyl group with an alcohol in the presence of an acid catalyst. In this case, the reaction temperature is preferably 100°C or less to prevent side reactions such as gelation.

[0085] The mother compound of the phenolic compound (A) is commercially available from, for example, Honshu Chemical Industry Co., Ltd. or Asahi Organic Chemicals Co., Ltd., and can be used. Alternatively, it can be synthesized by condensation of various phenolic compounds with various aldehydes or ketones.

[0086] In the negative resist composition according to the present disclosure, the phenolic compound (A) may be one of the compounds described above, or a mixture of two or more of them. However, in the negative resist composition according to the present disclosure, the purity of the phenolic compound (A) with the same structural formula is preferably 70% by mass or more, from the viewpoint of forming a good pattern, and more preferably 80% by mass or more, and even more preferably 90% by mass or more, of the phenolic compound (A) with the same structural formula. It is presumed that if a compound with the same structural formula and high purity is used as the phenolic compound (A), the development will proceed uniformly. However, even if the purity of a compound having the same structural formula as the phenolic compound (A) is less than the above-mentioned value, the impurity can be suitably used if the structure of the impurity is similar to that of the phenolic compound (A) and compatibility is good.

[0087] The phenolic compound used in the present disclosure preferably does not have a molecular weight distribution. Even if the phenolic compound used in the present disclosure has a molecular weight distribution, it is preferable that the molecular weight distribution is small, and the molecular weight distribution (mass average molecular weight <mw>and number average molecular weight Ratio of <mw> / is preferably 1.0 to 1.1.

[0088] The content of the phenolic compound (A) relative to the total solid content of the resist composition is 70% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more, and may be 95% by mass or more, 98% by mass or more, 99% by mass or more, or even 100% by mass. On the other hand, when the resist composition contains an organic basic compound (B) described below, the content of the phenolic compound (A) may be 99.9 mass % or less, or may be 99.1 mass % or less, based on the total solid content of the resist composition. In the present disclosure, the solid content refers to all components contained in the negative resist composition other than the organic solvent.

[0089] <Organic basic compound (B)> It is preferable that the non-chemically amplified negative resist composition used in the present disclosure further contains an organic basic compound (B), because this makes it easier to control the height of the convex portions with high precision in proportion to the exposure dose, and improves gradation exposure performance. When the non-chemically amplified negative resist composition used in the present disclosure further contains an organic basic compound (B), unlike the organic basic compounds in chemically amplified resist compositions that are used as quenchers for acid generators, it becomes possible to control the condensation reaction between the specific phenolic compounds (A) so that they are somewhat less likely to occur, making it easier to control the height of the convex portions with high precision in proportion to the exposure dose, and it is presumed that gradational exposure performance is improved.

[0090] The organic basic compound (B) can be selected from known organic basic compounds.

[0091] Examples of the organic basic compound (B) include, but are not limited to, nitrogen-containing organic compounds, such as nitrogen-containing compounds having a nitrogen atom, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds. Among these nitrogen-containing organic compounds, compounds containing polar groups in the chain, such as ether bonds, carbonyl bonds, ester bonds, carbonate bonds, sulfide bonds, and sulfone bonds, and compounds containing polar groups, such as ester groups, acetal groups, cyano groups, alkoxy groups, and hydroxyl groups, as substituents are also suitable.

[0092] Examples of the nitrogen-containing organic compound include mono(cyclo)alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-dodecylamine, and cyclohexylamine; di(cyclo)alkylamines such as di-n-butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, methyl-n-dodecylamine, di-n-dodecylmethylamine, cyclohexylmethylamine, and dicyclohexylamine; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, and dicyclohexylamine; tri(cyclo)alkylamines such as ethanolamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, dimethyl-n-dodecylamine, di-n-dodecylmethylamine, dicyclohexylmethylamine, and tricyclohexylamine; alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; aromatic amines such as aniline, N-methylaniline, N,N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, tribenzylamine, and 1-naphthylamine;Ethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis(4-aminophenyl)propane, 2-(3-aminophenyl)-2-(4-aminophenyl)propane, 2-( 4-aminophenyl)-2-(3-hydroxyphenyl)propane, 2-(4-aminophenyl)-2-(4-hydroxyphenyl)propane, 1,4-bis[1-(4-aminophenyl)-1-methylethyl]benzene, 1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene, polyethyleneimine, 2,2-(phenylimino)diethanol, polyallylamine, polymer of N-(2-dimethylaminoethyl)acrylamide, tris(2-acetoxyethyl)amine, tris( 2-pivaloyloxyethyl)amine, tris(2-t-butoxycarbonyloxyethyl)amine, tris[2-(2-oxopropoxy)ethyl]amine, tris[2-(methoxycarbonylmethyl)oxyethyl]amine, tris[2-(t-butoxycarbonylmethyloxy)ethyl]amine, tris[2-(2-methoxyethoxy)ethyl]amine, N-[2-(methylsulfonyl)ethyl]diethanolamine, N-[2-(methylsulfonyl)ethyl]bis(2-acetoxyethyl)amine amine, N-[2-(methylsulfonyl)ethyl]bis(2-formyloxyethyl)amine, N-[2-(methylsulfonyl)ethyl]bis(2-methoxyethyl)amine, dimethyl 3,3'-[2-(methylsulfonyl)ethyl]iminodipropionate, N-(tetrahydrofurfuryl)bis[2-(methylsulfonyl)ethyl]amine, t-butyl 3-[bis(2-methoxyethyl)amino]propionate, t-butyl 3-[bis(2-acetoxyethyl)amino]propionate, and the like.

[0093] Examples of the amide group-containing compound include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone.

[0094] Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tri-n-butylthiourea.

[0095] Examples of the nitrogen-containing heterocyclic compounds include imidazoles such as imidazole, benzimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, 2-phenylbenzimidazole, 4,5-diphenylimidazole, and 2,4,5-triphenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, nicotinic acid, and nicotinic acid. pyridines such as tin amide, quinoline, 8-oxyquinoline, and acridine; and pyrazine, pyrazole, pyridazine, quinoxaline, purine, pyrrolidine, piperidine, morpholine, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane, 1-[2-(methoxymethoxy)ethyl]pyrrolidine, 1-[2-(2-methoxyethoxy)methoxy]ethyl]pyrrolidine, 1-[2-(2-methoxyethoxy)methoxy]ethyl]piperidine. 1-(2',3'-dihydroxypropyl)-2-methylimidazole, 1,3-di(2'-methyl-1'-imidazolylmethyl)benzene, 1-benzyl-2-methylimidazole, 1-benzylimidazole, 2-(1H-benzimidazol-1-yl)ethyl acetate, 2-(2-phenyl-1H-benzoyl)ethyl acetate 1-[2-(1,3-dioxolan-2-yl)ethyl]1H-benzimidazole, 4-(1H-benzimidazol-1-yl)butyronitrile, t-butyl 3-morpholinopropionate, t-butyl 3-piperidinopropionate, 1-ethylcyclopentyl 3-piperidinopropionate, and 1-ethyl 2-norbornyl 3-piperidinopropionate.

[0096] The organic basic compound (B) may be an organic basic compound containing a hydroxyl group, which improves compatibility with the phenolic compound (A). The organic basic compound containing a hydroxyl group may be at least one of an amine compound containing a hydroxyl group and a nitrogen-containing heterocyclic compound containing a hydroxyl group.

[0097] The organic basic compound (B) may be a secondary amine compound. For example, piperidine corresponds to both a nitrogen-containing heterocyclic compound and a cyclic secondary amine compound.

[0098] The organic basic compound (B) may be a secondary amine compound having a hydroxyl group, such as 3-hydroxy-piperidine, 4-hydroxy-piperidine, or diethanolamine.

[0099] These organic basic compounds (B) can be used alone or in combination of two or more. The content of the organic basic compound (B) may be appropriately selected depending on the improvement of gradation exposure performance, and is, for example, preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the phenolic compound (A). If the content is less than 0.01 part by mass, the effect of adding the organic basic compound (B) may not be obtained. The content of the organic basic compound (B) may be 0.01 mass % or more, or 0.09 mass % or more, or 10 mass % or less, or 9.1 mass % or less, or 5 mass % or less, relative to the total solid content of the resist composition.

[0100] <Other ingredients> The non-chemically amplified negative resist composition of the present disclosure is non-chemically amplified, and therefore does not substantially contain an acid generator. Here, "substantially not containing" refers to not containing an acid generator to an extent that it substantially functions as a chemically amplified resist composition. In the case of a non-chemically amplified resist composition, the content of the photoacid generator is less than 1 part by mass, or even 0 parts by mass, per 100 parts by mass of the phenolic compound (A). The content of the photoacid generator is preferably less than 2% by mass relative to the total solids content of the resist composition, and may be 0% by mass.

[0101] The non-chemically amplified negative resist composition of the present disclosure uses the above-mentioned specific phenolic compound (A), and therefore does not need to contain a phenolic compound that does not have a hydroxymethyl group or an alkoxymethyl group. Phenolic compounds that do not fall under the category of the above-mentioned phenolic compound (A) of the present application, such as phenolic compounds that do not have a hydroxymethyl group or an alkoxymethyl group, may be contained within a range that does not impair the effects of the present disclosure, but it is preferable not to contain them in order to achieve low line edge roughness.

[0102] Furthermore, because the non-chemically amplified negative resist composition of the present disclosure uses the specific phenolic compound (A), it is not necessary to separately include a crosslinking agent as has been conventionally used. However, a small amount of a crosslinking agent may be added to improve resist sensitivity, provided that the effects of the present disclosure are not impaired. The content of such a crosslinking agent is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total solids content of the resist composition.

[0103] The crosslinking agent that does not fall under the specific phenolic compound (A) is not particularly limited and can be arbitrarily selected from known crosslinking agents used in conventional chemically amplified negative resist compositions. Examples include aliphatic cyclic hydrocarbons or oxygen-containing derivatives thereof having a hydroxyl group, a hydroxyalkyl group, or both, such as 4,4'-methylenebis[2,6-bis(hydroxymethyl)]phenol (MBHP), 4,4'-methylenebis[2,6-bis(methoxymethyl)]phenol (MBMP), 2,3-dihydroxy-5-hydroxymethylnorbornane, 2-hydroxy-5,6-bis(hydroxymethyl)norbornane, cyclohexanedimethanol, 3,4,8 (or 9)-trihydroxytricyclodecane, 2-methyl-2-adamantanol, 1,4-dioxane-2,3-diol, and 1,3,5-trihydroxycyclohexane. Further, a melamine-based crosslinking agent, a urea-based crosslinking agent, an alkylene urea-based crosslinking agent, or a glycoluril-based crosslinking agent may be used.

[0104] Furthermore, the non-chemically amplified negative resist composition of the present disclosure may contain an oligomer or polymer component to improve the performance of the resist film, as long as the effects of the present disclosure are not impaired. Adding an oligomer or polymer component can introduce a network structure into the resist film, thereby improving the pattern strength and improving the resolution and pattern shape (line edge roughness). The content of such an oligomer or polymer component is preferably 5% by mass or less, more preferably 3% by mass or less, based on the total solids content of the resist composition. Examples of oligomer or polymer components include alkali-developable resins that have conventionally been used in negative resist compositions for i-line, KrF, or ArF, such as novolak resins, polyhydroxystyrene derivatives, and acrylic copolymers derived from acrylic acid or methacrylic acid. These oligomer or polymer components may have a reactive functional group. The mass average molecular weight of the oligomer or polymer component is preferably 2000 to 30000, more preferably 2000 to 20000. The mass average molecular weight here refers to a polystyrene-equivalent value measured by GPC (gel permeation chromatography).

[0105] The negative resist composition of the present disclosure can further contain, as desired, compatible additives, such as additional resins for improving the performance of the resist film, surfactants for improving coatability, dissolution inhibitors, plasticizers, stabilizers, colorants, and antihalation agents, as long as the effects of the present disclosure are not impaired. In the non-chemically amplified negative resist composition of the present disclosure, the total content of the specific phenolic compound (A) and the organic basic compound (B) relative to the total solids content of the resist composition may be 90 mass % or more, 95 mass % or more, 97 mass % or more, or even 100 mass %.

[0106] <Preparation of Non-Chemically Amplified Negative Resist Composition> The non-chemically amplified negative resist composition according to the present disclosure is usually prepared by uniformly mixing the specific phenolic compound (A), and, if necessary, the organic basic compound (B), and other additives in an organic solvent.

[0107] The organic solvent may be any solvent commonly used for resists, such as ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, diethylene glycol dimethyl ether, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, or tetrahydrofuran, and these solvents may be used alone or in combination. Furthermore, alcohols such as isopropyl alcohol, ethyl alcohol, methyl alcohol, n-butyl alcohol, s-butyl alcohol, t-butyl alcohol, isobutyl alcohol, 2-methyl-1-pentanol, 4-methyl-2-pentanol, 2-methoxyethanol, 2-ethoxyethanol, 1-ethoxy-2-propanol, and 1-methoxy-2-propanol, and aromatic solvents such as toluene and xylene may also be contained. In the present disclosure, among these organic solvents, diethylene glycol dimethyl ether, cyclohexanone, cyclopentanone, 1-ethoxy-2-propanol, ethyl lactate, as well as safe solvents such as propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and mixed solvents thereof are preferably used. The amount of solvent in the resist composition is not particularly limited, and is set appropriately depending on the coating film thickness so as to provide a concentration that allows application to a substrate, etc. In general, the solvent is used so that the solids concentration of the resist composition falls within the range of preferably 0.5 to 20 mass %, more preferably 0.5 to 15 mass %.

[0108] The water content of the non-chemically amplified negative resist composition according to the present disclosure is preferably adjusted to 0.5% by mass or less, more preferably 0.01 to 0.5% by mass, and even more preferably 0.15 to 0.30% by mass. The water content can be adjusted, for example, by appropriately drying the materials used or by drying the preparation atmosphere (for example, to a humidity of 50% or less).

[0109] Furthermore, the non-chemically amplified negative resist composition according to the present disclosure has an acid component content of 1×10 -3 Milli-equivalent / g or less, and 5 x 10 -4 It is preferable to adjust the acid content to milliequivalents / g or less. The acid content can be adjusted, for example, by treating the solution of the material or composition used with an ion exchange resin or by washing the solution of the material used with pure water. The acid content can be determined by measuring the potential difference in a non-aqueous system. After preparation, the non-chemically amplified negative resist composition according to the present disclosure is preferably filtered before use.

[0110] Furthermore, the non-chemically amplified negative resist composition used in the present disclosure can achieve a slope γ of 2.0 or less in the rising slope of the resist film thickness in the sensitivity curve (contrast curve) of the exposure dose and the resist film thickness after development, and by further incorporating the organic basic compound (B), the slope γ can be further reduced to 1.0 or less. Therefore, the height of the convex portions can be easily controlled with high precision in accordance with the exposure dose, making the composition suitable as a negative resist composition for gradational exposure. The slope γ here is a value calculated as the slope of an approximate straight line in the range of 0.0-0.5 normalized resist film thickness after development, and the exposure dose is mC / cm 2 It is calculated as follows.

[0111] (2) A step of applying the negative resist composition onto a substrate and then heat treating the substrate to form a resist film. In this step, first, the non-chemically amplified negative resist composition is applied onto a substrate. "On a substrate" does not only mean a case where the composition is directly applied to a substrate, but also means a case where the composition is applied to another layer, such as an adhesive layer, on the substrate. The substrate and adhesive layer may be the same as those described above for the three-dimensional mold. The application method is not particularly limited as long as it is a method that can uniformly apply the non-chemically amplified negative resist composition to the surface of the substrate, and various methods such as spraying, roll coating, slit coating, and spin coating can be used.

[0112] Next, the non-chemically amplified negative resist composition coated on the substrate is pre-baked (PAB) to remove the organic solvent and form a resist film. The pre-baking temperature may be appropriately determined depending on the components of the composition, the proportions used, the type of organic solvent, etc., and is usually 80 to 160° C., preferably 90 to 150° C. The pre-baking time is usually about 30 seconds to 15 minutes. The thickness of the resist film is not particularly limited and may be adjusted appropriately depending on the concave-convex pattern shape according to the use of the three-dimensional mold. The thickness of the resist film may be, for example, 0.1 μm to 5.0 μm, or may further be 1.0 μm to 2.0 μm.

[0113] 3. A step of exposing the resist film to light and developing it (1) Gradation exposure process In this step, first, the resist film is subjected to gradation exposure. Gradient exposure refers to supplying energy to cure the negative resist composition in a gradational manner. The gradation exposure method may be appropriately selected from known methods. For example, exposure may be performed through a gradation mask having a predetermined pattern shape using an exposure device such as an electron beam lithography device or an EUV exposure device, or gradation exposure may be selectively performed by lithography using direct irradiation with an electron beam without using a gradation mask.

[0114] The gradation mask may be appropriately selected from known gradation masks, such as a halftone mask and a slit mask (gray tone mask). In addition, as a method for selectively performing gradation exposure by drawing or the like using direct irradiation with an electron beam without using a gradation mask, gradation exposure can be performed by, for example, changing the acceleration voltage or exposure dose by adjusting the focus of exposure, using the gradation exposure function of a drawing exposure machine, etc. By performing gradation exposure on the resist film, the resist composition in the resist film undergoes a curing reaction in accordance with the magnitude of the exposure dose.

[0115] The exposure light source is not particularly limited, and examples include ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV (Extreme Ultraviolet), electron beam, X-ray, and ion beam of helium, hydrogen, etc.

[0116] Next, after the exposure, post-exposure baking (PEB) may be performed. Since a non-chemically amplified resist composition does not substantially contain a photoacid generator, there is no need to perform post-exposure baking to diffuse the acid. However, since post-exposure baking can sometimes improve the sensitivity of the non-chemically amplified negative resist composition of the present disclosure, it is preferable to perform post-exposure baking as appropriate. The PEB treatment conditions are usually a temperature of 50 to 160° C. and a time of about 0.1 to 15 minutes.

[0117] (2) Development process Next, the substrate having the resist film after the gradational exposure, which has been subjected to PEB treatment as necessary, is developed using an alkaline developer to remove the unirradiated and uncured portions of the resist film. Examples of the developing method include a spray method, a slit method, a puddle method, a dipping method, and a swing immersion method. In addition, alkaline developers for the non-chemically amplified negative resist compositions used in the present disclosure include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia; primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldimethylamine; alcohol amines such as dimethylethanolamine and triethanolamine; quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, and choline; and cyclic amines such as pyrrole and piperidine. Furthermore, the above-mentioned alkaline aqueous solutions can also be used by adding an appropriate amount of alcohols such as isopropyl alcohol or a nonionic surfactant. Among these alkaline developers, aqueous solutions of quaternary ammonium salts are preferred, and aqueous solutions of tetramethylammonium hydroxide and choline are more preferred.

[0118] Furthermore, when a tetramethylammonium hydroxide (TMAH) aqueous solution is used as the alkaline developer, the concentration of the tetramethylammonium hydroxide aqueous solution is preferably 0.1% to 25%, more preferably 0.2% to 5%, and particularly preferably 0.2% to 2.38%. A 2.38% tetramethylammonium hydroxide aqueous solution is generally the most readily available in the semiconductor industry. Furthermore, if the concentration of the tetramethylammonium hydroxide aqueous solution is lower than 0.1%, the developer is neutralized by carbon dioxide in the air, resulting in fluctuations in sensitivity and making it difficult to obtain a stable product.

[0119] After the development treatment, a rinse treatment is carried out to wash away the alkaline developer on the substrate and the resist composition dissolved by the alkaline developer, and the substrate is then dried to obtain a resist pattern. The resist pattern obtained in this manner becomes a concave-convex pattern layer having a concave-convex pattern shape with convex portions of different heights and / or convex portions with inclined surfaces, and the three-dimensional mold of the present disclosure can be produced.

[0120] II. Negative resist composition for gradation exposure Another embodiment of the present disclosure provides a negative resist composition for gradational exposure, which contains: a phenolic compound (A) having a molecular weight of 400 to 2500, which has two or more phenolic hydroxyl groups per molecule and has two or more substituents per molecule selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions to the phenolic hydroxyl groups; and an organic basic compound (B), wherein the content of the phenolic compound (A) relative to the total solids content of the negative resist composition is 70 wt % or more; and the negative resist composition is substantially free of an acid generator and is a non-chemically amplified type.

[0121] A negative resist composition for gradational exposure according to one embodiment of the present disclosure contains the specific phenolic compound (A) and an organic basic compound (B), wherein the content of the phenolic compound (A) relative to the total solid content of the negative resist composition is 70% by weight or more, and the composition is substantially free of an acid generator and is a non-chemically amplified resist composition. As a result, as described above, it is possible to control the organic basic compound (B) so that the condensation reaction between the specific phenolic compounds (A) themselves is somewhat less likely to occur, making it easier to control the height of the convex portions with high precision in proportion to the exposure dose, and improving gradational exposure performance.

[0122] The negative resist composition for gradational exposure according to one embodiment of the present disclosure may be the same as the negative resist composition containing an organic basic compound (B) among the negative resist compositions described in the method for producing a three-dimensional mold according to one embodiment of the present disclosure, and therefore a detailed description thereof will be omitted here.

[0123] The negative resist composition for gradational exposure according to one embodiment of the present disclosure can be used for producing the three-dimensional molds described above, as well as for applications such as semiconductor integrated circuits, recording media, MEMS, and optical devices.

[0124] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0125] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to these examples. In the production examples, the structures and physical properties were confirmed using the following devices. MALDI-TOF MS: Manufactured by BRUKER, REFLEX II 1 H-NMR: JEOL, JEOL JNM-LA400WB Purity: Measured using high performance liquid chromatography (HPLC) (Shimadzu LC-10ADvp) under the following conditions: temperature: 40°C, flow rate: 1.0 mL / min, column: VP-ODS (4.7 mm × 150 mm), detector: SPD-M10Avp, mobile phase: acetonitrile / water. Glass transition temperature (Tg): Using a differential thermal analyzer (Shimadzu Corporation, "DSC-60"), approximately 4 mg of the pattern forming material was heated to 200°C at a rate of 10°C / min, cooled to room temperature, and then heated again to 200°C at a rate of 10°C / min. The glass transition temperature was determined as the intersection of both tangents to the smooth curve before and after the inflection temperature portion of the DTA curve. If no inflection point corresponding to the glass transition temperature was observed in the DTA curve up to 200°C, the Tg was determined to be 200°C or higher.

[0126] <Synthesis Example 1: Synthesis of phenolic compound (A-01)> To a solution consisting of 20 mL of 10% by mass potassium hydroxide aqueous solution and 20 mL of ethanol, 6.3 g (10 mmol) of a phenolic compound represented by the following chemical formula (1) (TekOC-4HBPA, Honshu Chemical Industry Co., Ltd.) was added and stirred at room temperature to dissolve. To this solution, 7.0 mL (80 mmol) of 37% formalin aqueous solution was slowly added at room temperature. After stirring at 40°C for 24 hours under a nitrogen atmosphere, the solution was poured into 200 mL of water in a beaker. While cooling in an ice bath, 2.0 wt% acetic acid aqueous solution was slowly added until the pH reached 5.0. The precipitate was filtered, thoroughly washed with water, and then dried. Purification was performed using high-performance liquid chromatography to obtain 5.8 g of a phenolic compound (A-01) represented by the following chemical formula (2). The structure of the obtained phenolic compound 1 (A-01) was confirmed by 1 Analysis was performed using H-NMR spectroscopy and MALDI-TOF MS. The glass transition temperature (Tg) was determined by differential scanning calorimetry. The analysis results are shown in Table 1 below.

[0127] [ka]

[0128] [ka]

[0129] 1 H-NMR:0.44(6H,-CH3), 1.09-1.67(14H, c Hex), 2.03(12H, Ph-CH3), 2.64-2.67(4H, c Hex), 4.44-4.51(8H,Ph-CH2-OH), 5.19-5.25(4H,Ph-CH2-OH), 6.74-7.02(8H, Aromatic H), 8.10-8.13(4H,Ph-OH) Purity: 92% MALDI-TOF MS: 752.97 Glass transition temperature (Tg): 200°C or higher

[0130] [Production Example 1: Negative Resist Composition 1 for Gradient Exposure of the Present Disclosure] 25.17 mass% of the phenolic compound (A) obtained in Synthesis Example 1, 3.55 mass% of 3-hydroxypiperidine as the organic basic compound (B), and 71.28 mass% of an organic solvent (propylene glycol monomethyl ether) were mixed to form a homogeneous solution, and the sample solution was filtered through a 0.1 μm Teflon (registered trademark) filter to prepare the non-chemically amplified negative resist composition of Production Example 1.

[0131] [Production Example 2: Negative Resist Composition 2 for Gradient Exposure of the Present Disclosure] 25.17 mass% of the phenolic compound (A) obtained in Synthesis Example 1, 3.55 mass% of 4-hydroxy-piperidine as the organic basic compound (B), and 71.28 mass% of an organic solvent (propylene glycol monomethyl ether) were mixed to form a homogeneous solution, and the sample solution was filtered through a 0.1 μm Teflon (registered trademark) filter to prepare a non-chemically amplified negative resist composition of Production Example 2.

[0132] [Production Example 3: Non-chemically amplified negative resist composition 3] Furthermore, a homogeneous solution was prepared by mixing the phenolic compound (A) and an organic solvent in the amounts shown in Table 2, and then filtering the solution through a 0.1 μm Teflon (registered trademark) filter to prepare the non-chemically amplified negative resist composition of Production Example 3. Note that the non-chemically amplified negative resist composition of Production Example 3 does not contain the organic basic compound (B), and therefore does not correspond to the negative resist composition for gradational exposure of another embodiment of the present disclosure.

[0133] [Evaluation of non-chemically amplified negative resist compositions (sensitivity curve)] Each non-chemically amplified negative resist composition was uniformly coated onto a 6-inch silicon substrate using a spinner, and pre-baked (PAB) at 110°C for 60 seconds to form a 2µm thick resist film. The resist film was then patterned using an electron beam lithography system (acceleration voltage 100keV) with the exposure dose varied within a 1mm square. After patterning, the resist was developed in a 2.38% TMAH aqueous solution (23°C) for 60 seconds and rinsed with pure water for 60 seconds to obtain a resist hardened pattern corresponding to the exposure dose. The sensitivity was measured by measuring the height of the hardened resist relative to the exposure dose using a microstructure measuring instrument (ET4000 manufactured by Kosaka Laboratory) to obtain a sensitivity curve (contrast curve) of the exposure dose and the resist film thickness after development, as shown in FIG.

[0134] [Example 1: Manufacturing of a 3D mold] Using the negative resist composition 1 for gradational exposure according to the present disclosure obtained in Production Example 1, a concave-convex pattern was formed by the method described below, to produce a three-dimensional mold. (1) Applying resist The negative resist composition for gradation exposure was uniformly applied onto a 6-inch silicon substrate using a spinner, and then prebaked (PAB) at 110° C. for 60 seconds to form a resist film with a thickness of 2 μm. (2) Resist pattern formation The resist film was then subjected to electron beam lithography (acceleration voltage 100 keV). Specifically, the resist heights to be formed were assigned to layers based on the sensitivity curves obtained in advance, and the appropriate exposure dose was set for each layer. After lithography, the resist was developed in a 2.38% TMAH aqueous solution (23°C) for 60 seconds, and then rinsed in pure water for 60 seconds to form a concave-convex pattern. The cross-sectional shape of the concave-convex pattern was observed using a scanning electron microscope (SEM) (manufactured by ZEISS). Fig. 13 shows a scanning electron microscope photograph of the cross section of the three-dimensional mold of Example 1.

[0135] [Example 2: Manufacturing of a 3D mold] Using the negative resist composition 2 for gradational exposure according to the present disclosure obtained in Production Example 2, a concave-convex pattern was formed by the method described below, to produce a three-dimensional mold. (1) Applying resist The negative resist composition for gradation exposure was uniformly applied onto a 6-inch silicon substrate using a spinner, and then prebaked (PAB) at 110° C. for 60 seconds to form a resist film with a thickness of 2 μm. (2) Resist pattern formation The resist film was then subjected to electron beam lithography (acceleration voltage 100 keV). Specifically, the resist heights to be formed were assigned to layers based on the sensitivity curves obtained in advance, and the appropriate exposure dose was set for each layer. After lithography, the resist was developed in a 2.38% TMAH aqueous solution (23°C) for 60 seconds, and then rinsed in pure water for 60 seconds to form a concave-convex pattern. The cross-sectional shape of the concave-convex pattern was observed using a scanning electron microscope (SEM) (manufactured by ZEISS). Fig. 14 shows a scanning electron microscope photograph of the cross section of the three-dimensional mold of Example 2.

[0136] Table 1 shows the measurement results of the cross-sectional shapes of the three-dimensional molds of Examples 1 and 2.

[0137] [Table 1]

[0138] [Table 2]

[0139] [Summary of results] The sensitivity curves of Production Examples 1 to 3 shown in Figure 12 indicate that the non-chemically amplified negative resist compositions of Production Examples 1 to 3, which contain a specific amount of the specific phenolic compound (A) used in the three-dimensional mold production method of the present disclosure, are suitable for gradational exposure because the height of the convex portions is easily controlled depending on the exposure dose. In particular, the negative resist composition for gradational exposure according to another embodiment of the present disclosure, which contains an organic basic compound (B) and is non-chemically amplified, can further reduce the slope γ, thereby making it easier to control the height of the convex portions with high precision depending on the exposure dose, and is therefore suitable as a negative resist composition for gradational exposure.

[0140] Referring to Figures 13 and 14, it has been revealed that a three-dimensional mold manufactured using the manufacturing method of the present disclosure can form convex portions with inclined surfaces in its cross-sectional shape with small spacing between adjacent convex portions, and the radius of curvature of the arc of the rising portion at the bottom of the convex portion is small, and the ratio of the radius of curvature (R) to the height (H) of the convex portion is also small, making it possible to manufacture a three-dimensional mold having a concave-convex pattern that is close to an ideal shape. [Explanation of symbols]

[0141] 1 Convex part 2 recesses 3. Concave and convex pattern shape 5,5' End of convex part 10. Textured pattern layer 20 PCB 30 Adhesion layer 40 Exposure 100 3D mold < / mw> < / mw>

Claims

1. A method for manufacturing a three-dimensional mold having a concave-convex pattern shape including at least one of convex portions having different heights and convex portions having inclined surfaces, the method comprising: a negative resist composition comprising: a phenolic compound (A) having a molecular weight of 400 to 2500, which has two or more phenolic hydroxyl groups per molecule and has two or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho-positions of the phenolic hydroxyl groups per molecule, and an organic basic compound (B), wherein the content of the phenolic compound (A) relative to the total solid content of the negative resist composition is 70 wt % or more, and the content of the acid generator is less than 1 part by mass per 100 parts by mass of the phenolic compound (A), A method for manufacturing a three-dimensional mold, comprising the steps of: exposing the resist film to gradational light and developing the exposed resist film.

2. The method for producing a three-dimensional mold according to claim 1 , wherein the organic basic compound (B) is an organic basic compound containing a hydroxyl group.

3. The method for manufacturing a three-dimensional mold according to claim 1 or 2, wherein the minimum distance between adjacent convex portions of the convex portions is 500 nm or less.

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