JP2022142294A - Method for manufacturing three-dimensional mold and negative resist composition for gradation exposure - Google Patents

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

The present disclosure relates to a method for manufacturing a three-dimensional mold and a negative resist composition for gradation exposure.

2. Description of the Related Art In recent years, in the manufacture of semiconductor devices and display devices, the progress of lithography technology has led to rapid miniaturization of patterns, and high resolution is required.
As a technique for miniaturization, the wavelength of the exposure light source is generally shortened, and in addition to the currently used KrF excimer laser light, ArF, F ₂ , EUV, X-rays, electron beams and other charged particles are used. Lithography using a line or the like as exposure light has been proposed.

Techniques that can replace conventional lithography techniques are being explored, and one of them is, for example, a technique in which a mold is produced by electron beam irradiation and nanoimprint lithography is performed using the mold. In the nanoimprint lithography, an original mold in which a nanometer-sized pattern is formed in advance is pressed against a resin material on a substrate to transfer the mold, thereby forming a fine concave-convex pattern.
In nanoimprint lithography, the mold is most important from the point of view of determining the precision of the product. Therefore, a method for producing a high-resolution mold is desired for a mold that serves as an original plate for nanoimprint lithography, and development of a resist material with high resolution that can be used for the production of the mold is also desired.

Conventionally, microfabrication methods using electron beam irradiation, for example, mainly produce two-dimensional patterns with the same height or depth, such as line and space, and three-dimensional molds with varying heights, depths, line widths, etc. There were few examples of application to pattern making.
For example, Patent Document 1 discloses an irradiation step of irradiating the resist layer of a workpiece having a resist layer composed of organopolysiloxane on a substrate with an electron beam, and developing the resist layer after irradiating the electron beam. and a developing step of forming irregularities in the resist layer, wherein in the irradiation step, irradiation is performed at an accelerating voltage such that primary electrons do not reach the substrate but secondary electrons reach the substrate. A method of making a three-dimensional mold is disclosed, comprising:
However, in the three-dimensional mold manufacturing method of Patent Document 1, the sensitivity of organopolysiloxane is low, so there is a problem that a low acceleration voltage must be used under a feasible exposure dose. In addition, there is a problem that resolution performance deteriorates due to the low acceleration voltage, and that only thin film resists can be handled.

As the resist material, for example, for the purpose of providing a negative gradation photoresist, which is disclosed in Patent Document 2, has high resolution and high sensitivity, is developable in water or an aqueous solution, and is not chemically amplified, Photoresists are disclosed that bridge between polymer chains based on rearrangement of carbon-oxygen bonds in pendant ester groups of polymers such as poly(methoxyethoxyethyl methacrylate).
However, when such a polymer material having alkali developability and crosslinkability is used, it tends to swell during development, has a large molecular weight, and has a wide molecular weight distribution. Further development of resist materials suitable for exposure has been demanded.

Therefore, low-molecular-weight materials have been developed as alkali-soluble resins that serve as resist substrates.
The present applicant has developed a chemically amplified or non-chemically amplified negative resist composition that has high post-exposure line width stability in a vacuum, high resolution, and is capable of obtaining a pattern with low line edge roughness. Molecular weight having two or more hydroxyl groups per molecule and one or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups in the ortho position of the phenolic hydroxyl group per molecule A negative resist composition containing 400 to 2500 of a phenolic compound (A), wherein the content of the phenolic compound (A) in the total solid content of the negative resist composition is 70% by mass or more. A certain negative resist composition is disclosed (Patent Document 3).
However, Patent Document 3 does not describe anything about performing gradation exposure or forming an uneven pattern having at least one of convex portions having different heights and convex portions having inclined surfaces. do not have.
Further, the basic compound described in Patent Document 3 is merely described as a quencher for suppressing diffusion of acid generated from an acid generator in a chemically amplified negative resist composition. There is no mention of combining a phenolic compound (A) with a basic compound without using an acid generator in a non-chemically amplified negative resist composition.

JP 2007-293046 A JP-A-2001-92135 Japanese Patent No. 5083478

The resist for manufacturing a three-dimensional pattern has analog properties that can control the processing height (processing depth) according to the exposure amount of electron beams, that is, according to the gradation exposure that exposes in gray scale. is required.
However, conventional chemically amplified negative resist compositions are not suitable for gradation exposure because it is difficult to control the processing height according to the exposure dose, although the sensitivity is enhanced by the acid generator.
In addition, conventionally known resist materials, which are easy to control the processing height according to the exposure dose, have low resolution.

In view of the above circumstances, the first object of the present disclosure is to produce a three-dimensional mold having a concavo-convex pattern shape with at least one of convex portions with different heights and convex portions with inclined surfaces at high resolution. , is to provide a method of manufacturing.
The second object of the present disclosure is that alkali development is possible in pattern formation by electron beam, ion beam, or EUV irradiation, and the height of the convex portion can be easily controlled according to the amount of exposure, and the gradation can be achieved. To provide a negative resist composition for gradation exposure which is suitable for exposure and capable of forming a three-dimensional pattern with excellent resolution.

One embodiment of the present disclosure is a method for manufacturing a three-dimensional mold having a concavo-convex pattern shape including at least one of convex portions having different heights and convex portions having inclined surfaces,
Having two or more phenolic hydroxyl groups in one molecule, and 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 A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500, wherein the content of the phenolic compound (A) in the total solid content of the negative resist composition is 70% by weight The above steps of coating a substrate with a non-chemically amplified negative resist composition that does not substantially contain an acid generator and then heat-treating to form a resist film; To provide a method for manufacturing a three-dimensional mold, including the steps of gradational exposure and development.

In the method for producing a three-dimensional mold of the present disclosure, the negative resist composition further containing an organic basic compound (B) increases the height of the protrusions in proportion to the amount of exposure. It is preferable from the viewpoint that it becomes easy to control with accuracy and the gradation exposure performance is improved.
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.

In the method of manufacturing a three-dimensional mold according to the present disclosure, the minimum distance between adjacent protrusions of the protrusions may be 500 nm or less.

Another embodiment of the present disclosure has two or more phenolic hydroxyl groups in one molecule, and one or more substitutions selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups at the ortho positions of the phenolic hydroxyl groups. A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500 and having two or more groups in one molecule and an organic basic compound (B), wherein the negative resist composition contains A non-chemically amplified negative resist composition for gradation exposure in which the content of the phenolic compound (A) in the total solid content is 70% by weight or more, and which does not substantially contain an acid generator. offer.

In the negative resist composition for gradation exposure of the present disclosure, the organic basic compound (B) may be an organic basic compound containing a hydroxyl group.
In the negative resist composition for gradation exposure of the present disclosure, the organic basic compound (B) may have a molecular weight of less than 400.

According to the present disclosure, there is provided a method for manufacturing, with high resolution, a three-dimensional mold having a concavo-convex pattern with at least one of convexes with different heights and convexes with inclined surfaces. can be done.
In addition, according to the present disclosure, alkali development is possible in pattern formation by electron beam, ion beam, or EUV irradiation, the height of the convex portion can be easily controlled according to the amount of exposure, and the resolution is excellent. It is possible to provide a negative resist composition for gradation exposure that can form a three-dimensional pattern.

FIG. 1 is a perspective view schematically showing an example of a three-dimensional mold manufactured by the manufacturing method of the present disclosure. FIG. 2 is a cross-sectional view schematically showing a part of the EE' section of FIG. FIG. 3 is a cross-sectional view schematically showing a part of a cut surface of another example of the three-dimensional mold manufactured by the manufacturing method of the present disclosure. 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. 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. 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. 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. 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. 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. 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. FIG. 11 is a cross-sectional view for explaining the curvature radius R of the arc of the lower portion of the projection of the three-dimensional mold manufactured by the manufacturing method of the present disclosure. FIG. 12 shows sensitivity curves of the exposure amount and the resist film thickness after development of the non-chemically amplified negative resist compositions of Production Examples 1 to 3. FIG. 13 shows a scanning electron micrograph of a part of the cross section of the three-dimensional mold of Example 1. FIG. 14 shows a scanning electron micrograph of a part of the cross section of the three-dimensional mold of Example 2. FIG.

Hereinafter, embodiments, examples, and the like of the present disclosure will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different aspects, and should not be construed as being limited to the descriptions of the embodiments, examples, and the like exemplified below. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is only an example, and the interpretation of the present disclosure is not intended. It is not limited. In addition, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the existing figures, and detailed description thereof may be omitted as appropriate. Also, for convenience of explanation, the terms "upper" and "lower" may be used, but the up-down direction may be reversed.
As used herein, when a feature, such as a member or region, is "above (or below)" another feature, such as another member or region, unless otherwise specified, This includes not only being directly above (or directly below) another structure, but also above (or below) another structure, i.e. above (or below) another structure and between another structure. Including when the element is included.

In the present disclosure, "active energy ray" means 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 notation of a group (atomic group) in the present disclosure, the notation not describing substitution and unsubstitution includes not only those not having substituents but also those having substituents. For example, an "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). The divalent bond of an alkylene group includes not only cases from different carbon atoms (eg —CH ₂ CH ₂ —) but also divalent bonds from the same carbon atom (eg —CH ₂ —). Alkyl groups and cycloalkyl groups include saturated hydrocarbons as well as unsaturated hydrocarbons having double bonds, triple bonds, and the like. Cycloalkyl groups include not only monocyclic but also polycyclic hydrocarbons such as bicyclic and tricyclic hydrocarbons.
In the present disclosure, "phenolic hydroxyl group" means a hydroxyl group directly bonded to an aromatic ring such as benzene.
In this disclosure, the phrase "at least one of X and Y" means "(X), (Y), or (X and Y)."
In addition, in the present disclosure, "to" indicating a numerical range is used to include the numerical values before and after it as lower and upper limits.
Hereinafter, the three-dimensional mold manufacturing method and the negative resist composition for gradation exposure according to the present disclosure will be described in detail in order.

I. Method for manufacturing three-dimensional mold A method for manufacturing a three-dimensional mold according to an embodiment of the present disclosure is to form a concavo-convex pattern shape having at least one of convex portions having different heights and convex portions having inclined surfaces. A method for manufacturing a three-dimensional mold having
Having two or more phenolic hydroxyl groups in one molecule, and 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 A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500, wherein the content of the phenolic compound (A) in the total solid content of the negative resist composition is 70% by weight The above steps of coating a substrate with a non-chemically amplified negative resist composition that does not substantially contain an acid generator and then heat-treating to form a resist film; gradation exposing and developing.

In the method for manufacturing a three-dimensional mold according to one embodiment of the present disclosure, a resist film is prepared using the specific non-chemically amplified negative resist composition, and a gradation exposure is performed to increase the height. A three-dimensional mold having a concavo-convex pattern with at least one of different convexes and convexes with inclined surfaces can be manufactured with high resolution.
In the method for manufacturing a three-dimensional mold according to one embodiment of the present disclosure, since the height of the convex portion can be controlled with high accuracy in proportion to the amount of exposure, convex portions with different heights and inclined surfaces can be formed. A three-dimensional mold having a desired concave-convex pattern with convex portions can be manufactured with high precision.
The specific non-chemically amplified negative resist composition has a relatively gentle slope γ in the sensitivity curve (contrast curve) between the exposure dose and the resist film thickness after development, and depending on the magnitude of the exposure dose It is presumed that the height of the protrusions can be easily controlled, the resist film does not easily swell during development, the molecular weight is relatively small, and the molecular weight distribution is narrow. .

Hereinafter, the manufacturing method of such a three-dimensional mold of the present disclosure will be described in detail in sequence.
1. Three-dimensional mold The three-dimensional mold manufactured by the manufacturing method of the present disclosure has a concavo-convex pattern shape including at least one of convex portions having different heights and convex portions having inclined surfaces.
A 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 EE' section of FIG. It is a diagram.
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 each other in a common direction Y. Prepare.

In the present disclosure, the cross-sectional shape of the three-dimensional mold is defined as the three-dimensional mold standing still on a horizontal plane. In the example of FIG. 1, the X-axis is taken in the repeating direction of the periodic structure, the Y-axis is taken perpendicular to the X-axis so that the XY form a horizontal plane, and the Z-axis is taken in a direction perpendicular to the XY horizontal plane. As shown in FIG. 2 , in the present disclosure, the bottom of the valley between the protrusions (minimum point of Z) is used as the reference for the height 0, and the portion with the height 0 is used as the recess 2 . Also, in the present disclosure, a portion having a height H (H>0) is defined as a convex portion 1 . On the other hand, in the present disclosure, the maximum height of the protrusions is used as a reference, and the depth to the bottom of the valley between the protrusions may be defined as the depth. When focusing on the , the height is used, and when focusing on the concave portion, the depth is used, and they are substantially the same. Therefore, when there are a plurality of valley bottoms (minimal points of Z) having different Z values among the valleys (minimal points of Z) between the convex portions, the convex portions having different heights have concave portions having different depths. (See, for example, FIG. 10 described later).
Also, as shown in FIG. 2, the interval (pitch) P between the adjacent protrusions 1 is set from one end 5 of a certain protrusion to one end 5' of the adjacent protrusion on the same side. do. The ends of the projections refer to portions starting to have a height H (H>0) from the bottom of the valley between the projections (minimum point of Z). The intervals (pitch) between the convex portions may be the same or different, or may have a predetermined repetition period.

The three-dimensional mold manufactured by the manufacturing method of the present disclosure may have other structures besides the concavo-convex pattern layer having the concavo-convex pattern shape. For example, the three-dimensional mold manufactured by the manufacturing method of the present disclosure may have a concavo-convex pattern layer formed on a substrate.
Furthermore, the three-dimensional mold manufactured by the manufacturing method of the present disclosure may be one in which the uneven pattern layer 10 is formed on the substrate 20 with the adhesion layer 30 interposed therebetween, as shown in FIG.

(1) Concavo-convex pattern shape The concavo-convex pattern shape of the three-dimensional mold manufactured by the manufacturing method of the present disclosure includes at least one type of convex portions having different heights and convex portions having inclined surfaces.
In the present disclosure, having a convex portion with a different height means that one convex portion may have a convex portion whose height changes in several stages (multi-step structure convex portion), or the heights may be different from each other. Convex portions (multivalued structure convex portions) may be provided, and convex portions (multivalued structure convex portions) having different heights may be provided with multilevel structure convex portions.
In addition, in the present disclosure, a convex portion having an inclined surface can also be said to be a form of a convex portion in which the height of one convex portion varies.

FIGS. 4 and 5 show an example of a convex portion (multi-step structure convex portion) whose height changes in several steps in one convex portion. In the present disclosure, in the cross-sectional shape, a convex portion having two or more flat portions (substantially horizontal portions) may be referred to as a multi-step shape, and the convex portions and concave portions of the multi-step shape are combined to form n flat portions. is sometimes referred to as an n-level shape. The example in FIG. 4 has a three-step shape, and the example in FIG. 5 has 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 are combined to form a two-step shape. Since the height is constant, there is no slope, and the reference value of the recess is constant, it does not correspond to the case of including at least one of the protrusions with different heights and the protrusions with slopes in the present disclosure.

FIG. 6 shows an example of a convex portion having inclined surfaces. 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 vertical nor horizontal with respect to the XY horizontal plane, and may have a curved surface. In the present disclosure, the inclination angle of the convex portion having the inclined surface may be, for example, 88 degrees or less, 85 degrees or less, 70 degrees or less, or 15 degrees with respect to the XY horizontal plane. 60 degrees or less and 45 degrees or less can also be formed. The cross-sectional shape of the convex portion having the inclined surface may be, for example, a triangular shape as shown in FIG. 2, a substantially triangular shape as shown in FIG. Shapes, parabolic, bell-shaped, semi-circular, semi-elliptical and other cross-sectional shapes can be mentioned.
In the present invention, when the cross-sectional shape of the convex portion having the inclined surface is a triangular shape as shown in FIG. 2 or a substantially triangular shape as shown in FIG. Conventionally, an obtuse angle of about 120 degrees was formed. It is also possible to form a convex portion having a

Further, FIGS. 7 to 10 show examples in which convex portions having different heights (multi-value structure convex portions) are provided. FIG. 8 shows an example in which convex portions (multilevel convex portions) having different heights are provided with multi-level convex portions. FIG. 9 shows an example in which convex portions having different heights (multi-value structure convex portions) are provided with convex portions having inclined surfaces. The convex portions having different heights may or may not have a predetermined repeating period.

According to the manufacturing method of the present disclosure, since a three-dimensional mold can be manufactured with high resolution, it is possible to manufacture a three-dimensional mold in which the minimum distance between adjacent convex portions is 500 nm or less, for example.
The minimum distance between adjacent protrusions of the protrusions may be appropriately selected according to the purpose of use of the uneven pattern of the three-dimensional mold, and is not particularly limited, but may be 400 nm or less, or 350 nm or less. or 300 nm or less.

Further, the aspect ratio defined by the height of the convex portion to the interval P between the adjacent convex portions ((height of the convex portion H)/(the adjacent convex portion interval P of the convex portion)) is the unevenness of the three-dimensional mold. It may be selected appropriately according to the purpose of use of the pattern, and is not particularly limited, but from the viewpoint of further etching the three-dimensional mold, it may be 5 or less, or 2 or less. On the other hand, from the viewpoint of using the three-dimensional mold as it is as a mold, the aspect ratio may be 0.25 or more.
In addition, in the present disclosure, as shown in FIG. 10, when the two ends of the projection have different heights, the maximum height is adopted as the height H of the projection.

In addition, according to the manufacturing method of the present disclosure, the height of the convex portion can be controlled with high accuracy in proportion to the amount of exposure, so it is easy to realize the desired uneven pattern shape.
Conventionally, when gradation exposure is performed using a negative resist composition, it has been difficult to form slopes or control the shape of portions where the amount of exposure is relatively low. For example, as shown in FIG. 11A, when forming a pattern having a triangular cross section as an ideal structure, the height of the convex portion is controlled in proportion to the amount of exposure 40. Conventionally, as shown in FIG. 11B, a portion with a small exposure amount adjacent to a portion with a relatively large amount of exposure is affected by the area with a relatively large amount of exposure, and a desired slope cannot be formed. Instead, the lower portion (rising portion) of the convex portion was rounded.
As an index for rounding the lower portion (rising portion) of the projection, as shown in FIG. It can be represented using H. The curvature radius R of the arc can be obtained by approximating a circle from the two coordinates of the arc. The curvature radius R of the arc can be obtained with reference to Japanese Patent Laid-Open No. 2004-125690. First, two initial straight lines are fitted from near both ends of the point sequence, then initial circular arcs are fitted to the remaining point sequences far from the initial two straight lines, and thereafter, line-arc-straight line fitting is iterated to obtain an arc can be obtained. According to the manufacturing method of the present disclosure, the radius of curvature of the arc at the bottom of the projection can be 50% or less of the height H of the projection. The radius of curvature of the arc at the bottom of the projection may be 40% or less, 30% or less, or 25% or less of the height H of the projection to approximate an ideal structure. good.

In the present disclosure, the distance P between adjacent protrusions, the height H of the protrusions, the width W of the protrusions, the radius of curvature R of the arc, etc. are determined by observing the cross section of the three-dimensional mold with an atomic force microscope. : AFM) or from an image taken with a scanning electron microscope (SEM).
In order to obtain the minimum interval between adjacent convex portions, if the interval P between adjacent convex portions is substantially constant, the number of adjacent convex portion intervals P to be obtained may be small. If so, it is preferable to obtain at least 5 cycles, and if the adjacent convex portion interval P changes without a period, it is preferable to obtain more adjacent convex portion intervals P.

If the uneven pattern shape of the three-dimensional mold manufactured by the manufacturing method of the present disclosure has convex portions with different heights formed using gradation exposure and convex portions with inclined surfaces, It is not particularly limited and can be implemented in many different ways.
The uneven pattern shape of the three-dimensional mold manufactured by the manufacturing method of the present disclosure may not have a periodic structure, and even if it has a periodic structure, it has a plurality of regions with different periodic structures. may be For example, the plurality of regions of the partial periodic structure may have protrusions with different shapes, heights, and intervals between adjacent protrusions.

(2) Concavo-convex pattern layer The concavo-convex pattern layer 10 having the concavo-convex pattern shape 3 is made of a cured product of the specific negative resist composition. Since the specific negative resist composition will be described later in detail, the description is omitted here.
The concavo-convex pattern layer having the concavo-convex pattern shape may not be connected at the lower portion of the convex portion. That is, the concavo-convex pattern layer may be composed of a group of convex portions without the cured product of the specific negative resist composition being present in the concavities of the concavo-convex pattern.

The thickness of the uneven pattern layer 10 is not particularly limited as long as it is appropriately adjusted according to the shape of the uneven pattern according to the application of the three-dimensional mold.
The thickness of the uneven pattern layer 10 may be, for example, 50 nm to 500 nm, and further may be 500 nm to 2000 nm.

(3) Substrate Substrates used in the three-dimensional mold manufactured by the manufacturing method of the present disclosure include quartz, glass, optical films, ceramic materials, evaporated films, magnetic films, reflective films, Ni, Cu, Cr, Fe, and the like. paper, SOG (Spin On Glass), polyester film, polycarbonate film, polyimide film and other polymer substrates, TFT array substrates, PDP electrode plates, glass and transparent plastic substrates, conductive substrates such as ITO and metal , insulating substrates, silicon, silicon nitride, polysilicon, silicon oxide, amorphous silicon, and other semiconductor fabrication substrates, etc. are not particularly limited. As the photomask substrate, a substrate having a light shielding layer or a low reflection layer such as CrxOyNz, MoSi, MoSiO, MoSiON, TaSiO, TaBO, TaBN on a transparent quartz glass substrate is preferably used.
The thickness of the substrate may be appropriately selected depending on the application, and is not particularly limited. The thickness of the substrate 20 may be, for example, 0.1 mm to 1 mm, or even 1 mm to 10 mm.

(4) Adhesion layer On the substrate used for the three-dimensional mold produced by the production method of the present disclosure, the specific negative resist composition or its cured product is provided on the substrate to improve adhesion to the substrate. It may have an adhesion layer surface-treated with an adhesion agent or the like.
Adhesion agents used in the adhesion layer include hexamethyldisilazane, silane coupling agents, acid anhydrides, phosphoric acid esters, etc. In particular, those having a functional group capable of reacting with the ethylenically unsaturated bond of the resin composition. 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), ACRYLOXYMETHYLTRIMETHOXYSILANE (trade name SIA0182.0, Gelest), β-carboxylethyl acrylate disclosed in JP-A-2009-503139 (trade name β-CEA, UCB Chemical), trade name Ebecryl3605 ( UCB Chemical), trade name Isorad 501 (Schenectady International, Inc.), compositions 1-5, and the like.
The thickness of the adhesion layer 30 may be appropriately selected according to the application and is not particularly limited, but may be, for example, 10 nm to 100 nm, or 100 nm to 2000 nm.
Note that the three-dimensional mold manufactured by the manufacturing method of the present disclosure may further have other configurations.

2. Step of forming a resist film In the three-dimensional mold manufacturing method of the present disclosure, a group having two or more phenolic hydroxyl groups in one molecule and consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500 and having two or more substituents selected from one or more substituents selected from After coating a substrate with a non-chemically amplified negative resist composition having a content of the phenolic compound (A) of 70% by weight or more in the solid content and containing substantially no acid generator. and heat treatment to form a resist film.

(1) Negative Resist Composition The specific phenolic compound (A) is added to a specific relatively low-molecular-weight phenolic compound that serves as a resist substrate, and a hydroxymethyl group is added as a crosslinkable group to the ortho-position of the phenolic hydroxyl group. , and an alkoxymethyl group. That is, the specific phenolic compound (A) is a resist substrate that also functions as a cross-linking agent.
The specific phenolic compound (A) has a high ratio of crosslinkable groups to hydroxyl groups and a high content of the phenolic compound (A) in the total solid content of the resist composition. Therefore, when the non-chemically amplified negative resist composition of the present disclosure is irradiated with an active energy ray, a cross-linking reaction by the cross-linkable group of the specific phenolic compound (A) proceeds without the intervention of an acid. do.
The negative resist composition has phenolic hydroxyl groups and is therefore alkali-soluble. Due to the presence of one or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups present at the positions, cross-linked bonds are formed, resulting in alkali insolubility. Therefore, in forming a resist pattern, when a resist film made of the negative resist composition is selectively exposed to light, the exposed portion becomes alkali-insoluble, while the unexposed portion remains alkali-soluble and does not change. A negative resist pattern can be formed.
In addition, since the non-chemically amplified negative resist composition of the present disclosure uses the specific phenolic compound (A) with a relatively low molecular weight in a state where the solid content of the resist composition is high, The uniformity of the resist composition is improved, and since the diffusion of acid is not used during image formation, the height of the convex portion can be easily controlled according to the amount of exposure. estimated to be superior to

Hereinafter, each configuration of such a negative resist composition of the present disclosure will be described in detail in order.
<Phenolic compound (A)>
The phenolic compound (A) used in the present disclosure has two or more phenolic hydroxyl groups in one molecule, and is selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group. It is a compound having a molecular weight of 400 to 2,500 and having two or more substituents in one molecule. By setting the molecular weight of the phenolic compound (A) within the above range, excellent resolution can be obtained.

The phenolic compound (A) used in the present disclosure may have two or more phenolic hydroxyl groups per molecule, and the number of phenolic hydroxyl groups per 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.
As the phenolic compound (A), it is preferable to select and use one having a development rate of 0.5 nm/sec or more with respect to an aqueous tetramethylammonium hydroxide (TMAH) solution (23° C.) having a concentration of 25% by mass. It is preferable to select and use one having a velocity of 0 nm/sec or more. By setting the alkali developing speed of the alkali-soluble resin within the above range, the pattern shape can be improved.

For example, the development rate for a tetramethylammonium hydroxide (TMAH) aqueous solution (23° C.) having a concentration of 25% by mass is obtained by, for example, using the phenolic compound (A) alone to obtain, for example, a 5% by mass solution, and a silicon wafer. After forming a coating film so that the film thickness after drying is 300 nm, it is immersed in an aqueous solution of tetramethylammonium hydroxide (TMAH) with a concentration of 25% by mass (23 ° C.) until the coating film is completely dissolved. Time can be measured and calculated.

The phenolic compound (A) used in the present disclosure has at least one substituent selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group, and has two or more substituents per molecule. do it. At least one substituent selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group functions as a crosslinkable group for the phenolic compound. The phenolic compound (A) used in the present disclosure has 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 three or more substituents per molecule. Having 4 or more in one molecule is preferable from the viewpoint of enhancing the crosslinkability.

The alkoxymethyl group preferably has 1 to 6 carbon atoms, and specific examples include methoxymethyl, ethoxymethyl, n-propoxymethyl, isopropoxymethyl and n-butoxymethyl groups. , sec-butoxymethyl group, t-butoxymethyl group, and various pentyloxymethyl groups. As the alkoxymethyl group, a methoxymethyl group and an ethoxymethyl group are particularly preferable from the viewpoint of good sensitivity.

As the crosslinkable group, among others, one or more substituents selected from the group consisting of a hydroxymethyl group, a methoxymethyl group, and an ethoxymethyl group at the ortho position of the phenolic hydroxyl group have high reactivity, It is preferable from the viewpoint of good sensitivity.

A compound having a molecular weight of 400 to 2500 is selected and used as the phenolic compound (A) used in the present disclosure. If the molecular weight is less than the lower limit, the ability to form a resist film and the ability to form a pattern may be deteriorated. On the other hand, if the molecular weight exceeds the upper limit, the resist composition tends to swell with the solvent used in the resist composition, tends to cause pattern collapse, and may deteriorate the shape of the pattern. The molecular weight here refers to the sum of the atomic weights of atoms constituting the molecule. Moreover, in the case of an oligomer having a molecular weight distribution, it is represented by a weight average molecular weight using GPC (converted to polystyrene).
The molecular weight of the phenolic compound (A) used in the present disclosure is preferably from 500 to 2,500, more preferably from 600 to 2,000 from the viewpoint of film-forming properties and resolution.

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. When the glass transition temperature is 60° C. or higher, dewetting is less likely to occur during coating film formation, making it easier to obtain a uniform film. The dewetting phenomenon refers to a phenomenon in which a spread coating film dissolves during prebaking, repelling occurs, and a uniform film is not formed.
Usually, when a solvent with a low boiling point is used as a solvent for a resist composition, the resist film dries rapidly and a uniform film cannot be obtained. For this purpose, solvents with a boiling point of 90-180° C. are used. Since the resist film formed by the spin coating method contains a large amount of residual solvent, the resist substrate is heated on a hot plate at a temperature of 90° C. or higher (pre-baking) in order to remove this solvent and form a stable resist film. . However, if a phenolic compound having a glass transition temperature of less than 60° C. is used, dewetting of the resist film may occur in the prebaking process, making it impossible to obtain a uniform film.
On the other hand, when using a phenolic compound with a glass transition temperature of 60 ° C. or higher, pre-baking at high temperatures is possible, and a uniform film can be obtained, as well as a resist film with excellent environmental resistance (post-coating delay: PCD). is obtained. Furthermore, it is possible to suppress the density dependency of the pattern that occurs during pattern formation by electron beams. In addition, in a dry etching step after forming a resist pattern, a pattern excellent in etching resistance (can prevent melting of the pattern due to high temperature during etching) can be obtained.
In addition, the glass transition temperature here is measured by a differential scanning calorimeter (DSC).

Moreover, 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 rapid drying of the resist film during spin coating, and there is an advantage that a uniform resist film can be obtained. 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, 1-ethoxy-2-propanol, and the like. is mentioned.

Among them, the phenolic compound (A) used in the present disclosure has a glass transition temperature (Tg) of 60° C. or higher and a boiling point of 5% by mass or more at 23° C. in an organic solvent having a boiling point of 80 to 180° C. preferably have a solubility of

The phenolic compound (A) is not particularly limited and can be appropriately selected and used. Examples thereof include compounds represented by the following chemical formulas (1) and (3).

［化学式（１）中、Ｒ^１は、各々独立に、水素原子、アルキル基、シクロアルキル基、アリール基、及び下記化学式（２）に示す基からなる群より選ばれる基であり、Ｒ^１に含まれるアリール基は、水酸基及びヒドロキシメチル基、及びアルコキシメチル基よりなる群から選択される１種以上の置換基を含んでいても良い。

[In the chemical formula ( ¹ ), each R ¹ is 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); The included aryl group may contain one or more substituents selected from the group consisting of a hydroxyl group, a hydroxymethyl group, and an alkoxymethyl group.

（化学式（２）中、Ｒ^４及びＲ^５は、各々独立に、水素原子又は炭素数１～３のアルキル基であり、Ｑは、アリール基又はシクロアルキル基であり、ｍは１又は２を表す。）
Ｒ^２は、各々独立に、水素原子又は１価の有機基であり、複数あるＲ^２のうち、１分子中少なくとも２個は水素原子である。Ｒ^３は、ハロゲン原子、アルキル基、シクロアルキル基、アリール基、アルコキシ基、アシル基、シアノ基、ニトロ基、ヒドロキシメチル基、及びアルコキシメチル基よりなる群から選ばれる基である。
ｎ１は１～３の整数、ｎ２は０～２の整数を表す。但し、ｎ１＋ｎ２≦４となる組み合わせをｎ１及びｎ２の数値範囲から選択するものとする。ｘ１は３～１２の整数を表す。
但し、Ｒ^１及び／又はＲ^３において、フェノール性水酸基のオルト位にヒドロキシメチル基、及びアルコキシメチル基よりなる群から選択される１種以上の置換基を１分子中に１個以上有する。
また、化学式（１）に含まれる同一符号で表される基は、互いに同じでも異なっていてもよい。］

(In chemical formula (2), R ⁴ and R ⁵ are 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. show.)
Each R ² is independently a hydrogen atom or a monovalent organic group, and among a plurality of R ² s, at least two in one molecule are hydrogen atoms. R3 is a group selected from the group consisting of halogen atoms ^, alkyl groups, cycloalkyl groups, aryl groups, alkoxy groups, acyl groups, cyano groups, nitro groups, hydroxymethyl groups, and alkoxymethyl groups.
n1 represents an integer of 1-3, and n2 represents an integer of 0-2. However, a combination that satisfies n1+n2≦4 is selected from the numerical ranges of n1 and n2. x1 represents an integer of 3 to 12;
However, in R ¹ and/or R ³ , one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group are present at the ortho-position to the phenolic hydroxyl group in one molecule.
In addition, the groups represented by the same reference numerals contained in chemical formula (1) may be the same or different. ]

（化学式（３）中、
Ｒ^６、Ｒ^７、Ｒ^８及びＲ^９は、各々独立に、水素原子、アルキル基、シクロアルキル基、アリール基、ヒドロキシメチル基、又はアルコキシメチル基、或いは、これらの組み合わせからなる基を表す。複数のＲ^６が結合して環を形成してもよい。複数のＲ^７が結合して環を形成してもよい。複数のＲ^８が結合して環を形成してもよい。複数のＲ^９が結合して環を形成してもよい。また、複数あるＲ^６、Ｒ^７、Ｒ^８及びＲ^９は互いに同じであっても異なっていても良い。
Ｒ^１０及びＲ^１１は、各々独立に、水素原子又は１価の有機基を表し、複数あるＲ^１０及びＲ^１１は互いに同じであっても異なっていても良い。また、複数あるＲ^１０及びＲ^１１のうち少なくとも２つは水素原子である。更に、Ｒ^６、Ｒ^７、及び／又はＲ^９において、フェノール性水酸基のオルト位にヒドロキシメチル基、及びアルコキシメチル基よりなる群から選択される１種以上の置換基を１分子中に１個以上有する。
Ｗは単結合、エーテル結合、チオエーテル結合、又は、ヘテロ原子を含んでいてもよい、アルキレン基、シクロアルキレン基、又はアリーレン基、或いは、これらの任意の組み合わせからなる基を表す。複数あるＷは互いに同じであっても異なっていても良い。
ｘ２は正の整数を表す。
ｙ１は０以上の整数を表し、Ｗが単結合の場合、ｙ１は０である。
ｙ２は０以上の整数を表し、ｙ３は正の整数を表す。
ｚは０以上の整数を表す。
ｖは０以上の整数を表す。
ｋ１及びｋ４は正の整数を表す。
ｋ２、ｋ３、及びｋ５は各々独立して０以上の整数を表す。但し、ｋ１＋ｋ２＋ｚ＝５、ｋ３＋ｖ＝３、ｋ４＋ｋ５＝５、ｋ２＋ｋ５≧２を満たす。）

(In the chemical formula (3),
R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represent 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. A plurality of ^R6 may combine to form a ring. Multiple ^R7s may combine to form a ring. A plurality of ^R8 may combine to form a ring. Multiple ^R9s may combine to form a ring. In addition, multiple R ⁶ , R ⁷ , R ⁸ and R ⁹ may be the same or different.
R ¹⁰ and R ¹¹ each independently represent a hydrogen atom or a monovalent organic group, and multiple R ¹⁰ and R ¹¹ may be the same or different. At least two of the plurality of R ¹⁰ and R ¹¹ are hydrogen atoms. Furthermore, in R ⁶ , R ⁷ and/or R ⁹ , one 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. have more than
W represents a single bond, an ether bond, a thioether bond, an optionally heteroatom-containing alkylene group, a cycloalkylene group, an arylene group, or a group consisting of any combination thereof. A plurality of W may be the same or different.
x2 represents a positive integer.
y1 represents an integer of 0 or more, and y1 is 0 when W is a single bond.
y2 represents an integer of 0 or more, and y3 represents a positive integer.
z represents an integer of 0 or more.
v represents an integer of 0 or more.
k1 and k4 represent positive integers.
k2, k3, and k5 each independently represent an integer of 0 or greater. However, k1+k2+z=5, k3+v=3, k4+k5=5, and k2+k5≧2 are satisfied. )

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

A hydroxyl group, an alkoxy group, a halogen atom, a halogenoalkyl group, etc. are mentioned as a substituent which an alkyl group has.

The cycloalkyl group for R ¹ is not particularly limited and includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and the like. Moreover, it may have unsaturated bonds such as double bonds and triple bonds, and may be either monocyclic or polycyclic.
A cyclohexyl group is preferred as the cycloalkyl group.

The substituents of the cycloalkyl group are not particularly limited, and examples thereof include alkyl groups having 1 to 5 carbon atoms, hydroxyl groups, alkoxy groups, alkoxyalkyl groups, halogen atoms, halogenoalkyl groups and the like.

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

The alkoxy group is not particularly limited, but is preferably an alkoxy group having 1 to 8 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, 2-ethylhexyloxy and the like.

The alkoxyalkyl group is not particularly limited, but is preferably an alkoxyalkyl group having 1 to 8 carbon atoms, such as methoxymethyl group, ethoxymethyl group, methoxyethyl group, ethoxyethyl group, methoxypropyl group and the like.

Halogen atoms include fluorine, chlorine, bromine and iodine atoms.

The halogenoalkyl group is not particularly limited, but is preferably a halogenoalkyl group having 1 to 8 carbon atoms, such as chloromethyl group, dichloromethyl group, trichloromethyl group, bromomethyl group, dibromomethyl group, tribromomethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-chloroethyl group, 1-bromoethyl group, 1-fluoroethyl group, 1,2-dichloroethyl group, 1,1,2,2-tetrachloroethyl group, etc. mentioned.

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

Examples of substituents of 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, a halogenoalkyl group, and the like. mentioned.
Examples of the cycloalkyl group as a substituent of the aryl group include the same cycloalkyl groups as those described above. In addition, 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, and the like. Examples of alkyl groups having 1 to 5 carbon atoms include methyl group, ethyl group and i-propyl group. The alkoxy group is not particularly limited, but is preferably an alkoxy group having 1 to 8 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, 2-ethylhexyloxy and the like.
The alkyl group, alkoxy group, alkoxyalkyl group, halogen atom, halogenoalkyl group and alkoxymethyl group having 1 to 5 carbon atoms as substituents of the aryl group are as described above.

In the above chemical formula (2), R ⁴ and R ⁵ are 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 linear or branched, and among them, a methyl group and an ethyl group are preferable from the viewpoint of etching resistance. When m is 2, each of two R ⁴ and R ⁵ may be the same or different.
In the above chemical formula (2), the case where both R ⁴ and R ⁵ are hydrogen atoms is preferably used.

Examples of the aryl group for Q in the chemical formula (2) include the same aryl groups as those described above. The substituents possessed by the aryl group of Q include the same substituents possessed by the above aryl group, and include one or more substituents selected from the group consisting of a hydroxyl group, a hydroxymethyl group, and an alkoxymethyl group. You can stay Further, examples of the cycloalkyl group for Q in the above chemical formula (2) include the same cycloalkyl groups as those described above. Examples of the substituent which the cycloalkyl group of Q has include the same substituents as those of the above cycloalkyl group.

The monovalent organic group for R ² is not particularly limited, and includes an alkyl group, a cycloalkyl group, and an aryl group.
Examples of the alkyl group for R ² include the same groups as those for R ¹ above. Examples of substituents possessed by the alkyl group of R ² include those similar to those of R ¹ above.
The cycloalkyl group of R ² and the substituent of the cycloalkyl group can be the same as those of R ¹ above. Furthermore, the aryl group for R ² and the substituents that the aryl group has may be the same as those for R ¹ above.

The alkoxymethyl group for R ³ is as indicated above.
Examples of the halogen atom and alkyl group for R ³ include the same as those for R ¹ above.
Substituents possessed by the alkyl group as R ³ include cycloalkyl groups, aryl groups, amino groups, amido groups, ureido groups, urethane groups, hydroxyl groups, carboxy groups, halogen atoms, alkoxy groups, thioether groups, acyl groups, and acyloxy groups. , an alkoxycarbonyl group, a cyano group, a nitro group, and the like.

The cycloalkyl group for R ³ and the substituents possessed by the cycloalkyl group can be the same as those for R ¹ above. The aryl group for R ³ and the substituents that the aryl group has may be the same as those for R ¹ above.
Further, examples of the alkoxy group for R ³ include the same groups as those for R ¹ above.

The acyl group for R ³ is not particularly limited, but is preferably an acyl group having 1 to 8 carbon atoms, and examples thereof include formyl, acetyl, propionyl, butyryl, valeryl, pivaloyl, and benzoyl groups. be done.

x1 is an integer of 3-12, preferably an integer of 4-12, more preferably an integer of 4-8.

The compound represented by the chemical formula (1) has two or more phenolic hydroxyl groups in one molecule, and is selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group. If one or more substituents are present, each repeating unit may have the same or different substituents indicated by the same reference numerals. The positions of OR ² and R ³ in each repeating unit may be the same or different.

In the compound represented by the above chemical formula (1), x1 is preferably 4 and n1 is 2 from the viewpoint of obtaining a pattern with high sensitivity and high resolution and good shape. 4, a calix resorcinarene derivative in which n1 is 2, 4 to 8 hydrogen atoms out of 8 R ² , and a hydroxymethyl group at the ortho position where R ² is a hydrogen atom, and alkoxymethyl It is preferable to have one or more substituents selected from the group consisting of groups in one molecule.
In addition, in the compound represented by the above chemical formula (1), x1 is preferably 4 and n1 is 2 from the viewpoint of obtaining a pattern with high sensitivity, high resolution, and good shape. a calix resorcinarene derivative in which x1 is 4, n1 is 2, and 0 to 8 hydrogen atoms among 8 R ² , and R ¹ has a phenolic hydroxyl group and an ortho position of the phenolic hydroxyl group preferably has an aryl group containing one or more substituents selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group.

On the other hand, in the compound represented by the above chemical formula (3), the alkyl groups in R ⁶ , R ⁷ , R ⁸ and R ⁹ may be linear or branched, preferably methyl, ethyl, propyl, butyl groups having 1 to 10 carbon atoms such as isobutyl group, hexyl group and octyl group.
Cycloalkyl groups for R ⁶ , R ⁷ , R ⁸ and R ⁹ may be monocyclic or polycyclic. Examples thereof include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure, etc., having 5 or more carbon atoms. It preferably has 6 to 30 carbon atoms, particularly preferably 7 to 25 carbon atoms. group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecanyl group, cyclododecanyl group and the like. These alicyclic hydrocarbon groups may have a substituent.
The aryl group for R ⁶ , R ⁷ , R ⁸ and R ⁹ may be the same as for R ¹ above.
The hydroxymethyl group or alkoxymethyl group for R ⁶ , R ⁷ , R ⁸ and R ⁹ may be the same as above.
In the compound represented by the above chemical formula (3), R ⁶ is a (x2)-valent group when (x2) is an integer of 2 or more.

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

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

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

In addition, the alkylene chain or cycloalkylene chain has -O-, -OC(=O)-, -OC(=O)O-, -N(R)-C(=O)-, -N (R)-C(=O)O-, -S-, -SO-, and -SO ₂ - may be included. Here, R is a hydrogen atom or an alkyl group (preferably having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, etc.).
The cyclic arylene group for W preferably includes those having 6 to 15 carbon atoms such as phenylene group, tolylene group and naphthylene group.

Specific examples of the phenolic compound (A) are shown below, but the present disclosure is not limited thereto. Two or more phenolic hydroxyl groups are present in one molecule, and one or more substituents selected from the group consisting of hydroxymethyl groups and alkoxymethyl groups are present in the ortho position of the phenolic hydroxyl group, and two or more substituents are present in one molecule. If present, the phenolic hydroxyl group in the specific examples below may be protected with an organic group.
Further, 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 L in one molecule are , a hydroxymethyl group present at the ortho-position to a phenolic hydroxyl group, and an alkoxymethyl group. Moreover, the molecular weight satisfies 400-2500.

The phenolic compound (A) used in the present disclosure has at least one substituent selected from the group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group in the core compound of the phenolic compound. can be obtained by introducing As a method for introducing a substituent that functions as a crosslinkable group into the core compound of a phenolic compound, for example, a phenolic compound that does not have a corresponding hydroxymethyl group is reacted with formaldehyde in the presence of a base catalyst. be able to. In this case, the reaction temperature is preferably 50° C. or lower in order to prevent side reactions such as gelation. Moreover, various bisphenol derivatives having an alkoxymethyl group can be obtained by reacting the corresponding bisphenol derivative having a hydroxymethyl group with an alcohol in the presence of an acid catalyst. In this case, the reaction temperature is preferably 100° C. or lower in order to prevent side reactions such as gelation.

The core compound of the phenolic compound (A) is commercially available from, for example, Honshu Kagaku Kogyo Co., Ltd., Asahi Organic Chemical Industry Co., Ltd., and the like can be used. It can also be synthesized by condensation of various phenol compounds and various aldehydes and ketones.

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

Phenolic compounds used in the present disclosure preferably do not have a molecular weight distribution. The phenolic compound used in the present disclosure preferably has a small molecular weight distribution even if it has a molecular weight distribution. /<Mn> is preferably 1.0 to 1.1.

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

<Organic basic compound (B)>
The non-chemically amplified negative resist composition used in the present disclosure further contains an organic basic compound (B) so that the height of the protrusions can be adjusted with high accuracy in proportion to the amount of exposure. It is preferable from the viewpoint of easier control and improved gradation exposure performance.
When the non-chemically amplified negative resist composition used in the present disclosure further contains an organic basic compound (B), the organic basicity of the chemically amplified resist composition used as a quencher for the acid generator Unlike a compound, it is possible to control the condensation reaction between the specific phenolic compounds (A) so that it is slightly difficult to occur, and it is easy to control the height of the convex portion with high accuracy in proportion to the amount of exposure. Therefore, it is estimated that the gradation exposure performance is improved.

As the organic basic compound (B), any known organic basic compound can be selected and used.

Examples of the organic basic compound (B) include nitrogen-containing organic compounds, such as nitrogen-containing compounds having a nitrogen atom, amide group-containing compounds, urea compounds, and nitrogen-containing heterocyclic compounds. It is not limited to these. In addition to these nitrogen-containing organic compounds, compounds containing polar groups such as ether bonds, carbonyl bonds, ester bonds, carbonate bonds, sulfide bonds, and sulfone bonds in the chain, ester groups, acetal groups, cyano groups, alkoxy groups, A compound containing a polar group such as a hydroxyl group as a substituent is also preferably used.

Examples of nitrogen-containing organic compounds include mono(cyclo)alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-dodecylamine and cyclohexylamine; -n-butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, methyl-n-dodecyl Di(cyclo)alkylamines such as amine, di-n-dodecylmethylamine, cyclohexylmethylamine, dicyclohexylamine; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri- n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, dimethyl-n-dodecylamine, di-n-dodecylmethylamine, dicyclohexylmethylamine, tri(cyclo)alkylamines such as tricyclohexylamine; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; aniline, N-methylaniline, N,N-dimethylaniline, 2-methylaniline, 3-methyl Aromatic amines such as aniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, tribenzylamine, 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, N- (2-dimethylaminoethyl)acrylamide polymer, 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, 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-3-[bis(2-acetoxyethyl)amino]propionate butyl and the like.

Examples of amide group-containing compounds include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, and the like. mentioned.

Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tri-n-butylthiourea. etc.

Nitrogen-containing heterocyclic compounds include, for example, imidazole, benzimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, 2-phenylbenzimidazole, 4,5-diphenylimidazole, 2,4,5-tri imidazoles such as phenylimidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine, nicotine, Pyridines such as nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, acridine; piperazine, 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, 3-hydroxy-piperidine, 4-hydroxy-piperidine, 4-[2-(methoxymethoxy)ethyl]morpholine, 4-[2-(2-methoxyethoxy)methoxy ] Ethyl]morpholine 1-(2′,3′-dihydroxylpropyl)-2-methylimidazole, 1,3-di(2′-methyl-1′-imidazolylmethyl)benzene, 1-benzyl-2-methyl imidazole, 1-benzylimidazole, 2-(1H-benzimidazol-1-yl)ethyl acetate, 2-(2-phenyl-1H-benzimidazol-1-yl)ethyl acetate, 3-(2-phenyl-1H- benzimidazol-1-yl)methyl propionate, 1-[2-(1,3-dioxolan-2-yl)ethyl]1H-benzimidazole, 4-(1H-benzimidazol-1-yl)butyronitrile, 3- t-butyl morpholinopropionate, t-butyl 3-piperidinopropionate, 1-ethylcyclopentyl 3-piperidinopropionate, 1-ethyl 2-norbornyl 3-piperidinopropionate and the like.

The organic basic compound (B) may be an organic basic compound containing a hydroxyl group from the viewpoint of improving compatibility with the phenolic compound (A). The hydroxyl-containing organic basic compound may be at least one of a hydroxyl-containing amine compound and a hydroxyl-containing nitrogen-containing heterocyclic compound.

Also, the organic basic compound (B) may be a secondary amine compound. For example, piperidine corresponds to a nitrogen-containing heterocyclic compound, but also to a cyclic secondary amine compound.

Also, the organic basic compound (B) may be a secondary amine compound having a hydroxyl group. Secondary amine compounds having a hydroxyl group include, for example, 3-hydroxy-piperidine, 4-hydroxy-piperidine, diethanolamine and the like.

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 according to the improvement of the gradation exposure performance. It is from 0.1 to 5 parts by mass, preferably from 0.1 to 10 parts by mass. If the amount is less than 0.01 part by mass, the effect of addition may not be obtained.
The content of the organic basic compound (B) may be 0.01% by mass or more, may be 0.09% by mass or more, and may be 10% by mass or less with respect to the total solid content of the resist composition. , may be 9.1% by mass or less, and may be 5% by mass or less.

<Other ingredients>
Since the non-chemically amplified negative resist composition of the present disclosure is non-chemically amplified, it does not substantially contain an acid generator. Here, "substantially does not contain" means that it does not contain to the extent that it substantially functions as a chemical amplification type. In the case of the non-chemically amplified resist composition, the content of the photoacid generator is less than 1 part by mass and may be 0 parts by mass with respect to 100 parts by mass of the phenolic compound (A). With respect to the total solid content, the standard is less than 2% by mass, and may be 0% by mass.

Since the non-chemically amplified negative resist composition of the present disclosure uses the specific phenolic compound (A), it does not need to contain a phenolic compound that does not have a hydroxymethyl group or an alkoxymethyl group. A phenolic compound that does not correspond to the above phenolic compound (A) of the present application, such as a phenolic compound that does not have a hydroxymethyl group or an alkoxymethyl group, may be included within a range that does not impair the effects of the present disclosure, but a low line edge It is preferable not to include it from the point of roughness.

In addition, since the non-chemically amplified negative resist composition of the present disclosure uses the specific phenolic compound (A), there is no need to separately include a conventionally used cross-linking agent. However, the resist sensitivity may be improved by adding a small amount of a cross-linking agent to the extent that the effects of the present disclosure are not impaired. The content of such a cross-linking agent can be 10% by mass or less, more preferably 5% by mass or less, relative to the total solid content of the resist composition.

The cross-linking agent that does not correspond to the specific phenolic compound (A) is not particularly limited, and can be arbitrarily selected from known cross-linking agents used in conventional chemically amplified negative resist compositions. can be used. For example, 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-adaman Aliphatic cyclic hydrocarbons having a hydroxyl group, a hydroxyalkyl group, or both, such as tanol, 1,4-dioxane-2,3-diol, and 1,3,5-trihydroxycyclohexane, or oxygen-containing derivatives thereof.
Further, a melamine-based cross-linking agent, a urea-based cross-linking agent, an alkylene urea-based cross-linking agent, or a glycoluril-based cross-linking agent may be used as the glycoluril-based cross-linking agent.

Further, to the non-chemically amplified negative resist composition of the present disclosure, an oligomer or polymer component for improving the performance of the resist film may be added to the extent that the effects of the present disclosure are not impaired. By adding an oligomer or polymer component to introduce a network structure into the resist film, it may be possible to improve resolution and pattern shape (line edge roughness) by increasing pattern strength. 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 solid content of the resist composition.
The oligomeric or polymeric component is derived from novolak resin, polyhydroxystyrene derivative, acrylic acid or methacrylic acid, which is an alkali-developable resin conventionally used in negative resist compositions for i-ray, KrF or ArF. acrylic copolymers. These oligomeric or polymeric components may have reactive functional groups.
The weight average molecular weight of the oligomer or polymer component is preferably 2000-30000, more preferably 2000-20000. The mass average molecular weight here refers to a polystyrene equivalent value measured by GPC (gel permeation chromatography) method.

The negative resist composition of the present disclosure may optionally contain miscible additives as long as the effects of the present disclosure are not impaired, such as additional resins for improving the performance of the resist film, Surfactants, dissolution inhibitors, plasticizers, stabilizers, colorants, antihalation agents and the like can be added as appropriate.
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) is 90% relative to the total solid content of the resist composition. It may be at least 95% by mass, at least 97% by mass, or at least 100% by mass.

<Preparation of non-chemically amplified negative resist composition>
The non-chemically amplified negative resist composition according to the present disclosure usually contains the specific phenolic compound (A), optionally the organic basic compound (B), and other additives in an organic solvent. Prepared by mixing to homogeneity.

As the organic solvent, those commonly used as solvents for resists can be used. For example, 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, dimethylsulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like are preferred, and these solvents can be used alone or in combination. Further 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.
In the present disclosure, among these organic solvents, diethylene glycol dimethyl ether, cyclohexanone, cyclopentanone, 1-ethoxy-2-propanol, ethyl lactate, and safe solvents propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate and mixed solvents thereof is preferably used.
The amount of the solvent in the resist composition is not particularly limited, and is appropriately set according to the coating film thickness at a concentration that can be applied to the substrate or the like. Generally, the solvent is used so that the resist composition has a solid content concentration of preferably 0.5 to 20% by mass, more preferably 0.5 to 15% by mass.

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

In addition, the non-chemically amplified negative resist composition according to the present disclosure preferably has an acid component content of 1×10 ⁻³ meq/g or less, more preferably 5×10 ⁻⁴ meq/g or less. . The acid component content can be adjusted, for example, by treating the material solution or composition solution used with an ion exchange resin, or by washing the material solution used with pure water. The acid component content can be determined by non-aqueous potentiometric measurements.
The non-chemically amplified negative resist composition according to the present disclosure is preferably used after being filtered after being prepared.

In addition, the non-chemically amplified negative resist composition used in the present disclosure has a sensitivity curve (contrast curve) between the exposure amount and the resist film thickness after development, in which the slope γ at the rise of the resist film thickness is 2.0 or less. Furthermore, by containing the organic basic compound (B), the slope γ can be further reduced to 1.0 or less. It is easy to control with high precision and is suitable for negative resist composition for gradation exposure.
The slope γ here is a value calculated as the slope of an approximate straight line in the range of normalized thickness of 0.0 to 0.5 after development, and the exposure dose (Dose) at that time is mC/cm ² is calculated.

(2) A step of applying the negative resist composition onto a substrate and then heat-treating to form a resist film. In this step, first, the non-chemically amplified negative resist composition is applied onto the substrate. .
The term "on the substrate" is not limited to the case where the coating is directly applied to the substrate, but when the substrate has another layer such as an adhesion layer, it may be on the other layer. The substrate and adhesion layer may be the same as those described in the three-dimensional mold.
The coating method is not particularly limited as long as it is a method capable of uniformly coating the non-chemically amplified negative resist composition on the substrate surface, and includes spraying, roll coating, slit coating, and spin coating. etc. various methods can be used.

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 according to the components of the composition, the proportion of use, the type of organic solvent, etc., and is usually 80 to 160°C, preferably 90 to 150°C. Also, the prebake time is usually about 30 seconds to 15 minutes.
The thickness of the resist film is not particularly limited as long as it is appropriately adjusted according to the uneven pattern shape according to the application of the three-dimensional mold. The thickness of the resist film may be, for example, 0.1 μm to 5.0 μm, and further 1.0 μm to 2.0 μm.

3. Step of Gradation Exposure and Development of the Resist Film (1) Step of Gradation Exposure In this step, first, the resist film is subjected to gradation exposure.
Gradation exposure refers to supplying energy for curing the negative resist composition in gradation.
As the gradation exposure method, a known method can be appropriately selected and used. For example, using an exposure apparatus such as an electron beam drawing apparatus or an EUV exposure apparatus, exposure may be performed through a gradation mask having a predetermined pattern shape, or direct irradiation of an electron beam without a gradation mask may be performed. Gradation exposure may be selectively performed by drawing with a .

As the gradation mask, a known gradation mask can be appropriately selected and used. Examples of gradation masks include halftone masks and slit masks (graytone masks).
Also, as a method of selectively performing gradation exposure by direct irradiation of an electron beam without passing through a gradation mask, for example, exposure focus adjustment, gradation exposure function of a drawing exposure machine, etc. can be used. , gradation exposure can be performed by changing the acceleration voltage and the amount of exposure. By subjecting the resist film to gradation exposure, the resist composition in the resist film advances a curing reaction according to the amount of exposure.

The exposure light source is not particularly limited, and may be performed using ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV ₍ Extreme Ultraviolet), electron beam, X-ray, ion beam such as helium or hydrogen. can be done.

After exposure, post exposure bake (PEB) may be performed. Since the non-chemically amplified resist composition does not substantially contain a photoacid generator, there is no need to perform post-exposure heating for diffusing the acid, but the non-chemically amplified negative type of the present disclosure Post-exposure heating may improve the sensitivity of the resist composition, so it is preferable to appropriately perform post-exposure heating.
The PEB treatment conditions are usually a temperature of 50 to 160° C. and a time of about 0.1 to 15 minutes.

(2) Developing step Next, the substrate provided with the resist film after the gradation exposure, which has been PEB-treated as necessary, is developed using an alkaline developer, so that the resist film is exposed. A portion not irradiated with light and an uncured portion are removed.
Examples of the developing method include a spray method, a slit method, a liquid heaping method, a dipping method, and a rocking immersion method.
In addition, as the alkaline developer for the non-chemically amplified negative resist composition used in the present disclosure, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, etc. , primary amines such as ethylamine and n-propylamine; secondary amines such as diethylamine and di-n-butylamine; tertiary amines such as triethylamine and methyldimethylamine; alcohols such as dimethylethanolamine and triethanolamine. Aqueous solutions of alkalis such as amines, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, quaternary ammonium salts such as choline, and cyclic amines such as pyrrole and piperidine can be used. Further, an alcohol such as isopropyl alcohol or a nonionic surfactant may be added in an appropriate amount to the aqueous alkali solution. Among these alkaline developers, preferred are quaternary ammonium salts, more preferred are aqueous solutions of tetramethylammonium hydroxide and choline.

Further, when a tetramethylammonium hydroxide (TMAH) aqueous solution is used as an alkaline developer, the concentration of the tetramethylammonium hydroxide aqueous solution is preferably 0.1% to 25%, more preferably 0.2%. to 5%, particularly preferably 0.2% to 2.38%. A 2.38% strength aqueous solution of tetramethylammonium hydroxide is generally the most available in the semiconductor industry. In addition, when the concentration of the tetramethylammonium hydroxide aqueous solution is less than 0.1%, the developing solution is neutralized by carbon dioxide in the air, and the sensitivity fluctuates, making it difficult to stably obtain products. Become.

After the development treatment, a rinsing treatment is performed to wash away the alkali developer and the resist composition dissolved by the alkali developer on the substrate, followed by drying to obtain a resist pattern.
The resist pattern thus obtained becomes a concavo-convex pattern layer having a concavo-convex pattern shape with convex portions having different heights and/or convex portions having inclined surfaces, and the three-dimensional mold of the present disclosure is manufactured. be able to.

II. Another embodiment of the negative resist composition for gradation exposure has two or more phenolic hydroxyl groups in one molecule, and a group consisting of a hydroxymethyl group and an alkoxymethyl group at the ortho position of the phenolic hydroxyl group. A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500 having two or more substituents in one molecule and one or more substituents selected from The content of the phenolic compound (A) in 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 non-chemically amplified. Provided is a negative resist composition for tonal exposure.

A negative resist composition for gradation exposure according to one embodiment of the present disclosure contains the specific phenolic compound (A) and the organic basic compound (B), and the total solid content of the negative resist composition The content of the phenolic compound (A) in the medium is 70% by weight or more, and the organic basic compound (B ) can be controlled so that the condensation reaction between the specific phenolic compounds (A) is slightly difficult to occur, and the height of the convex portion can be easily controlled with high accuracy in proportion to the amount of exposure. Improved exposure performance.

The negative resist composition for gradation exposure according to one embodiment of the present disclosure includes the 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. Since it may be the same as the negative resist composition containing, detailed description is omitted here.

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

Note that the present disclosure is not limited to the above embodiments. The above embodiment is an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present disclosure and produces similar effects is the present disclosure. included in the technical scope of

Hereinafter, the present disclosure will be specifically described with reference to examples. These descriptions are not intended to limit the present disclosure.
In addition, confirmation of the structure and physical properties in the production examples was performed using the following equipment.
MALDI-TOF MS: REFLEX II manufactured by BRUKER
¹ H-NMR: JEOL JNM-LA400WB manufactured by JEOL
Purity: Using high-performance liquid chromatography (HPLC) (Shimadzu Corporation LC-10ADvp), 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 ("DSC-60" manufactured by Shimadzu Corporation), about 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 , and the intersection point of both tangents of the smooth curves before and after the inflection temperature portion of the DTA curve when the temperature was raised to 200°C at a rate of 10°C/min was defined as the glass transition temperature. When no inflection point of the DTA curve corresponding to the glass transition temperature was observed up to 200°C, the Tg was judged to be 200°C or higher.

<Synthesis Example 1: Synthesis of phenolic compound (A-01)>
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 to a solution consisting of 20 mL of a 10% by mass potassium hydroxide aqueous solution and 20 mL of ethanol, and the mixture was stirred at room temperature. Stir and dissolve. 7.0 mL (80 mmoL) of a 37% formalin aqueous solution was slowly added to this solution at room temperature. Furthermore, after stirring at 40° C. for 24 hours under a nitrogen atmosphere, the mixture was poured into 200 mL of water in a beaker. While cooling this in an ice bath, a 2.0 wt % aqueous acetic acid solution was slowly added until the pH reached 5.0. The precipitate was filtered off, thoroughly washed with water, and then dried. Purification was performed by 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 H-NMR spectrum and MALDI-TOF MS. The glass transition temperature (Tg) was determined by differential scanning calorimetry. The analysis results are shown in Table 1 below.

¹ H-NMR: 0.44 (6H, —CH ₃ ), 1.09-1.67 (14H, ^c Hex), 2.03 (12H, Ph—CH ₃ ), 2.64-2.67 ( 4H, ^c Hex), 4.44-4.51 (8H, Ph—CH ₂ —OH), 5.19-5.25 (4H, Ph—CH ₂ —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

[Production Example 1: Negative resist composition 1 for gradation exposure of the present disclosure]
25.17% by mass of the phenolic compound (A) obtained in Synthesis Example 1, 3.55% by mass of 3-hydroxy-piperidine as the organic basic compound (B), and 71.28% by mass of an organic solvent (propylene glycol monomethyl ether) % by mass to form a uniform 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 1.

[Production Example 2: Negative resist composition 2 for gradation exposure of the present disclosure]
25.17% by mass of the phenolic compound (A) obtained in Synthesis Example 1, 3.55% by mass of 4-hydroxy-piperidine as the organic basic compound (B), and 71.28% by mass of an organic solvent (propylene glycol monomethyl ether) % by mass to form a uniform 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.

[Production Example 3: Non-Chemical Amplification Negative Resist Composition 3]
Also, the phenolic compound (A) and the organic solvent were mixed in the amounts shown in Table 2 to make a uniform solution, filtered through a 0.1 μm Teflon (registered trademark) filter, and the non-chemically amplified negative resist composition of Production Example 3 was obtained. was prepared. Since the non-chemically amplified negative resist composition of Production Example 3 does not contain the organic basic compound (B), the negative resist composition for gradation exposure according to another embodiment of the present disclosure has Not applicable.

[Evaluation of non-chemically amplified negative resist composition (sensitivity curve)]
Each non-chemically amplified negative resist composition was uniformly coated on a 6-inch silicon substrate using a spinner and prebaked (PAB) at 110° C. for 60 seconds to form a 2 μm-thick resist film. An electron beam drawing apparatus (accelerating voltage of 100 keV) was used to write on the above resist film while varying the exposure amount within a square of 1 mm. After the drawing was completed, development was performed with a 2.38% TMAH aqueous solution (23° C.) for 60 seconds, followed by rinsing with pure water for 60 seconds to obtain a resist hardened pattern corresponding to the exposure amount.
The sensitivity is measured by measuring the height of the resist cured product with respect to the exposure dose using a fine shape measuring machine (manufactured by Kosaka Laboratory: ET4000). Obtained.

[Example 1: Production of three-dimensional mold]
Using the negative resist composition 1 for gradation exposure of the present disclosure obtained in Production Example 1, a concavo-convex pattern was formed by the method shown below to produce a three-dimensional mold.
(1) Coating of resist A negative resist composition for gradation exposure was uniformly coated on a 6-inch silicon substrate using a spinner, and pre-baked (PAB) was performed at 110°C for 60 seconds to obtain a resist with a film thickness of 2 µm. A film was formed.
(2) Resist pattern formation Using an electron beam lithography system (acceleration voltage of 100 keV) for the above resist film, specifically, from the sensitivity curve obtained in advance, a layer ( Layer), and set the appropriate exposure for that layer and draw. After completion of the drawing, development processing was performed with a 2.38% TMAH aqueous solution (23° C.) for 60 seconds, and rinsing processing was performed with pure water for 60 seconds to form an uneven pattern.
The cross-sectional shape of the uneven pattern was observed with a scanning electron microscope (SEM) (manufactured by ZEISS). FIG. 13 shows a scanning electron micrograph of a cross section of the three-dimensional mold of Example 1. As shown in FIG.

[Example 2: Production of three-dimensional mold]
Using the negative resist composition 2 for gradation exposure of the present disclosure obtained in Production Example 2, a concavo-convex pattern was formed by the method shown below to produce a three-dimensional mold.
(1) Coating of resist A negative resist composition for gradation exposure was uniformly coated on a 6-inch silicon substrate using a spinner, and pre-baked (PAB) was performed at 110°C for 60 seconds to obtain a resist with a film thickness of 2 µm. A film was formed.
(2) Resist pattern formation Using an electron beam lithography system (acceleration voltage of 100 keV) for the above resist film, specifically, from the sensitivity curve obtained in advance, a layer ( Layer), and set the appropriate exposure for that layer and draw. After completion of the drawing, development processing was performed with a 2.38% TMAH aqueous solution (23° C.) for 60 seconds, and rinsing processing was performed with pure water for 60 seconds to form an uneven pattern.
The cross-sectional shape of the uneven pattern was observed with a scanning electron microscope (SEM) (manufactured by ZEISS). FIG. 14 shows a scanning electron micrograph of the cross section of the three-dimensional mold of Example 2. As shown in FIG.

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

[Summary of results]
According to the sensitivity curves of Production Examples 1 to 3 shown in FIG. It has been shown that the amplified negative resist composition is suitable for gradation exposure because the height of the projections can be easily controlled according to the amount of exposure. In particular, the negative resist composition for gradation exposure according to another embodiment of the present disclosure, which contains the organic basic compound (B) and is non-chemically amplified, can further reduce the slope γ. , it was shown that the height of the protrusions can be easily controlled with high accuracy according to the amount of exposure, and that it is suitable for a negative resist composition for gradation exposure.

Referring to FIGS. 13 and 14, the three-dimensional mold manufactured by the manufacturing method of the present disclosure has a cross-sectional shape in which protrusions having inclined surfaces can be formed with a small interval between adjacent protrusions, and It is possible to manufacture a three-dimensional mold having a concavo-convex pattern close to an ideal shape, in which the radius of curvature of the arc of the rising portion of is small, and the ratio of the radius of curvature (R) to the height (H) of the convex portion is also small. was revealed.

1 convex part 2 concave part 3 concave/convex pattern shape 5, 5' end of convex part 10 concave/convex pattern layer 20 substrate 30 adhesion layer 40 exposure 100 three-dimensional mold

Claims (7)

A method for manufacturing a three-dimensional mold having a concavo-convex pattern with at least one of convex portions having different heights and convex portions having inclined surfaces,
Having two or more phenolic hydroxyl groups in one molecule, and 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 A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500, wherein the content of the phenolic compound (A) in the total solid content of the negative resist composition is 70% by weight The above steps of coating a substrate with a non-chemically amplified negative resist composition that does not substantially contain an acid generator and then heat-treating to form a resist film; A method of manufacturing a three-dimensional mold, comprising the steps of gradational exposure and development. 2. The method for producing a three-dimensional mold according to claim 1, wherein said negative resist composition further contains an organic basic compound (B). 3. The method for producing a three-dimensional mold according to claim 2, wherein the organic basic compound (B) is an organic basic compound containing a hydroxyl group. The method for manufacturing a three-dimensional mold according to any one of claims 1 to 3, wherein the minimum distance between adjacent protrusions of said protrusions is 500 nm or less. Having two or more phenolic hydroxyl groups in one molecule, and 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 A negative resist composition containing a phenolic compound (A) having a molecular weight of 400 to 2500 and an organic basic compound (B), wherein the phenolic compound in the total solid content of the negative resist composition A non-chemically amplified negative resist composition for gradation exposure, containing (A) in an amount of 70% by weight or more and substantially free of an acid generator. 6. The negative resist composition for gradation exposure according to claim 5, wherein said organic basic compound (B) is an organic basic compound containing a hydroxyl group. 7. The negative resist composition for gradation exposure according to claim 5, wherein said organic basic compound (B) has a molecular weight of less than 400.

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