Resist composition and method for forming a resist film using the same

Abstract

The present invention provides a resist composition which contains a resin (A) and a solvent (B) containing a compound (B1) represented by general formula (b-1), and which contains an active ingredient in an amount of 45 mass% or less with respect to the total amount of the resist composition. [In formula (b-1), R1 represents an alkyl group having 1-10 carbon atoms.]

Description

[Technical Field]

[0001] The present invention relates to a resist composition and a method for forming a resist film using the resist composition. [Background technology]

[0002] Microfabrication using lithography with photoresist materials is performed in the manufacturing of semiconductor and liquid crystal devices. In particular, in the manufacturing of semiconductor devices, further miniaturization of pattern dimensions is required in recent years due to the increasing integration and speed of LSIs. To accommodate this miniaturization of pattern dimensions, the light source for lithography used in resist pattern formation has been shortened from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). For example, Patent Document 1 discloses an invention relating to a positive-type resist composition using a resin in which the hydroxyl groups of the carboxyl groups of (meth)acrylic acid are protected with acid-dissociable dissolution-inhibiting groups, as a photoresist material suitable for resist pattern formation using an ArF excimer laser.

[0003] In recent years, in addition to miniaturizing pattern dimensions, development of 3D structured devices has also progressed, aiming to increase memory capacity through stacking cells. In the manufacturing of 3D structured devices, a thick resist film with a higher thickness than conventional methods is fabricated before forming the resist pattern. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-241385 [Overview of the project] [Problems that the invention aims to solve]

[0005] Thus, the photoresist materials used in the manufacture of various devices such as semiconductor elements and liquid crystal elements have different required properties depending on the type of device. Therefore, there is a need for photoresist materials that can form resist films suitable for the manufacture of various devices. [Means for solving the problem]

[0006] The present invention provides a resist composition containing a resin and a solvent containing a compound having a specific structure, wherein the content of the active ingredient is limited to a predetermined value or less, and a method for forming a resist film using the resist composition. In other words, the present invention provides the following [1] to

[14] . [1] A resist composition comprising a resin (A) and a solvent (B) containing a compound (B1) represented by the following general formula (b-1), A resist composition wherein the content of the active ingredient on a total basis of the resist composition is 45% by mass or less. [ka] [In the above formula (b-1), R 1 This refers to an alkyl group having 1 to 10 carbon atoms. [2] The resist composition according to [1], further comprising at least one additive (C) selected from a photosensitive agent and an acid generator. [3] R in the general formula (b-1) 1 The resist composition according to [1] or [2] above, wherein the group is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, or a t-butyl group. [4] R in the general formula (b-1) 1 The resist composition according to any one of the above [1] to [3], wherein the group is an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, or a t-butyl group. [5] The resist composition according to any one of [1] to [4] above, wherein the solvent (B) comprises a solvent (B2) other than the compound (B1). [6] The resist composition according to [5] above, wherein the solvent (B) contains, as the solvent (B2), one or more selected from the group consisting of methyl α-methoxyisobutyrate, methyl α-formyloxyisobutyrate, methyl α-acyloxyisobutyrate, and methyl 3-hydroxyisobutyrate. [7] The resist composition according to [5] above, wherein the solvent (B) contains, as the solvent (B2), one or more selected from the group consisting of methyl α-methoxyisobutyrate, methyl α-formyloxyisobutyrate, methyl α-acyloxyisobutyrate, methyl 3-hydroxyisobutyrate, and 1-methoxy-2-propanol. [8] The resist composition according to any one of [5] to [7] above, wherein the solvent (B2) is contained in an amount of 100% by mass or less based on the total amount (100% by mass) of the compound (B1). [9] The resist composition according to [8] above, wherein the solvent (B2) is contained in an amount of less than 70% by mass based on the total amount (100% by mass) of the compound (B1).

[10] The resist composition according to [8] or [9] above, wherein the solvent (B2) is contained in an amount of 0.0001% by mass or more based on the total amount (100% by mass) of the compound (B1).

[11] The resist composition according to any one of [5] to

[10] above, wherein the solvent (B2) is contained in an amount of less than 100% by mass based on the total amount (100% by mass) of the resist composition.

[12] The resist composition according to any one of [1] to

[11] above, wherein the resin (A) contains a novolak-type resin (A1).

[13] The resist composition according to any one of [1] to

[11] above, wherein the resin (A) contains a resin (A2) having at least one of a structural unit (a2-1) derived from a phenolic hydroxyl group-containing compound and a structural unit (a2-2) capable of forming an acidic functional group by decomposition by the action of an acid, a base, or heat.

[14] The resist composition according to any one of [1] to

[11] above, wherein the resin (A) contains a resin (A3) having a structural unit (a3-1) having an adamantane structure.

[15] The resist composition according to

[14] above, wherein the resin (A3) is a copolymer having a structural unit (a3-2) having a lactone structure together with the structural unit (a3-1).

[16] The resist composition according to

[14] or

[15] above, wherein the content of the structural unit (a3-1α) having an adamantane structure substituted with a hydroxy group is less than 50 mol% with respect to the total amount of the structural units of the resin (A3).

[17] The resist composition according to any one of [1] to

[11] above, wherein the resin (A) contains a resin (A4) having at least two of the structural units: a structural unit (a2-1) derived from a phenolic hydroxyl group-containing compound, a structural unit (a2-2) capable of decomposing upon the action of an acid, a base or heat to form an acidic functional group, a structural unit (a3-1) having an adamantane structure, and a structural unit (a3-2) having a lactone structure.

[18] Step (1): A step of applying the resist composition according to any one of [1] to

[17] above onto a substrate to form a coating film. Step (2): A step of performing a heat treatment after step (1), and Step (3): A step of forming a resist pattern, which is a resist film forming method.

Effects of the Invention

[0007] In the resist composition of a preferred embodiment of the present invention, although the content of the active ingredient containing the resin is limited to a predetermined value or less, it is possible to form a resist film suitable for the manufacture of various devices.

Modes for Carrying Out the Invention

[0008] 〔Resist Composition〕 The resist composition of the present invention contains a resin (A) (hereinafter also referred to as "component (A)") and a solvent (B) represented by the general formula (b-1) (hereinafter also referred to as "component (B)"). The resist composition of the present invention is used for forming a resist film, but does not include a film used under the resist (for example, a resist auxiliary film such as a resist intermediate layer film or a resist lower layer film). Furthermore, it is preferable that the resist composition according to one embodiment of the present invention further contains at least one additive (C) (hereinafter also referred to as "component (C)") selected from photosensitive agents and acid generators. Furthermore, in the resist composition of the present invention, the content of the active ingredient is limited to 45% by mass or less based on the total amount (100% by mass) of the resist composition. In this specification, "active ingredient" means the components of the resist composition excluding component (B). Specifically, this includes resin (A) and additive (C), as well as other additives described later, such as acid crosslinking agents, acid diffusion control agents, dissolution accelerators, dissolution control agents, sensitizers, surfactants, organic carboxylic acids or phosphorus oxoacids or their derivatives, dyes, pigments, adhesion aids, anti-halation agents, preservation stabilizers, defoaming agents, shape modifiers, etc. Generally, for example, in order to manufacture three-dimensional structural devices, it is necessary to form a thick resist film, but when using a resist composition with a low resin content, it becomes difficult to form a thick resist film. In contrast, the resist composition of the present invention, by using a compound represented by general formula (b-1) as a solvent, can become a photoresist material capable of forming a thick resist film even when the content of the active ingredient, including the resin, is reduced to 45% by mass or less. Furthermore, because the content of the active ingredient in the resist composition of the present invention is reduced to 45% by mass or less, it also has economic advantages.

[0009] In addition, in a resist composition according to one embodiment of the present invention, the content of the active ingredient may be appropriately set according to the application, such as 42% by mass or less, 40% by mass or less, 36% by mass or less, 31% by mass or less, 26% by mass or less, 23% by mass or less, 20% by mass or less, 18% by mass or less, 16% by mass or less, 12% by mass or less, 10% by mass or less, 6% by mass or less, or 3% by mass or less, based on the total amount (100% by mass) of the resist composition. On the other hand, the lower limit of the active ingredient content is set appropriately according to the application, but it can be 1% by mass or more, 2% by mass or more, 4% by mass or more, 7% by mass or more, or 10% by mass or more, relative to the total amount (100% by mass) of the resist composition. Furthermore, the amount of active ingredient can be specified in any combination by appropriately selecting from the upper and lower limit options mentioned above.

[0010] Furthermore, in a resist composition according to one aspect of the present invention, from the viewpoint of providing a photoresist material capable of forming a thick resist film, the content ratio of component (A) in the active ingredient is preferably 50 to 100% by mass, more preferably 60 to 100% by mass, even more preferably 70 to 100% by mass, even more preferably 75 to 100% by mass, and particularly preferably 80 to 100% by mass, based on the total amount (100% by mass) of the active ingredient contained in the resist composition.

[0011] A resist composition according to one aspect of the present invention may contain other components in addition to the above-mentioned components (A) to (C), depending on the application. However, in a resist composition according to one aspect of the present invention, the total content of components (A), (B), and (C) is preferably 30 to 100% by mass, more preferably 40 to 100% by mass, even more preferably 60 to 100% by mass, even more preferably 80 to 100% by mass, and particularly preferably 90 to 100% by mass, based on the total amount (100% by mass) of the resist composition. The details of each component included in the resist composition according to one embodiment of the present invention will be described below.

[0012] <Component (A): Resin> The resin (A) included in the resist composition according to one embodiment of the present invention is not particularly limited, and known photoresists such as those for g-ray, i-ray, KrF excimer lasers, ArF excimer lasers, EUV, and EB lasers can be used and selected as appropriate depending on the application. In this specification, "resin" means not only polymers having predetermined structural units but also compounds having predetermined structures. The weight-average molecular weight (Mw) of the resin used in one aspect of the present invention is preferably 400 to 50,000, more preferably 1,000 to 40,000, and even more preferably 1,000 to 30,000.

[0013] In the resist composition of the present invention, the content of component (A) may be appropriately set according to the application, based on the total amount (100% by mass) of the resist composition, to be 45% by mass or less, 42% by mass or less, 40% by mass or less, 35% by mass or less, 31% by mass or less, 26% by mass or less, 23% by mass or less, 20% by mass or less, 18% by mass or less, 16% by mass or less, 12% by mass or less, 10% by mass or less, 6% by mass or less, or 3% by mass or less. Furthermore, the lower limit of the content of component (A) is set appropriately according to the application, but it can be 1% by mass or more, 2% by mass or more, 4% by mass or more, 7% by mass or more, or 10% by mass or more based on the total amount (100% by mass) of the resist composition. Furthermore, the content of component (A) can be specified in any combination by appropriately selecting from the upper and lower limit options mentioned above.

[0014] For example, when used as a photoresist material for manufacturing liquid crystal elements for ultraviolet exposure such as g-ray or i-ray light, it is preferable that the resin (A) includes a novolac-type resin (A1). Furthermore, when used as a photoresist material for a KrF excimer laser, it is preferable that resin (A) includes resin (A2) having at least one of constituent units derived from a phenolic hydroxyl group-containing compound and constituent units that can decompose by the action of an acid, base, or heat to form an acidic functional group. Furthermore, when used as a photoresist material for ArF excimer lasers, it is preferable that resin (A) includes resin (A3) having a constituent unit having an adamantane structure. When used as a photoresist material for EUV, it is preferable that resin (A) contains resin (A4) (excluding resins (A2) and resin (A3)) which has two or more constituent units from which constituent units are derived from a phenolic hydroxyl group-containing compound, constituent units that can decompose by the action of acid, base or heat to form an acidic functional group, constituent units having an adamantane structure, and constituent units having a lactone structure.

[0015] The resin (A) contained in the resist composition according to one embodiment of the present invention may contain only one of these resins (A1), (A2), (A3), and (A4), or it may contain a combination of two or more. Furthermore, resin (A) may contain other resins other than resins (A1), (A2), (A3), and (A4). However, the total content ratio of resins (A1), (A2), (A3), and (A4) in resin (A) used in one aspect of the present invention is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, even more preferably 80 to 100% by mass, even more preferably 90 to 100% by mass, and particularly preferably 95 to 100% by mass, relative to the total amount (100% by mass) of resin (A). The following describes these resins (A1), (A2), (A3), and (A4).

[0016] [Novolac-type resin (A1)] Examples of novolac-type resins (A1) used in one aspect of the present invention include resins obtained by reacting phenols with at least one of aldehydes and ketones in the presence of an acidic catalyst (e.g., hydrochloric acid, sulfuric acid, oxalic acid, etc.). The novolac-type resin (A1) is not particularly limited, and known resins can be used, for example, resins listed in Publication No. 2009-173623, International Patent Publication No. 2013-024778, and International Patent Publication No. 2015-137485 can be applied.

[0017] Examples of phenols include phenol, orthocresol, metacresol, paracresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, 2-methylresorcinol, 4-methylresorcinol, 5-methyl Examples include reresorcinol, 4-t-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 2-methoxy-5-methylphenol, 2-t-butyl-5-methylphenol, thymol, isothymol, 4,4'-biphenol, 1-naphthol, 2-naphthol, hydroxyanthracene, hydroxypyrene, 2,6-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene. These phenols may be used individually or in combination of two or more.

[0018] Examples of aldehydes include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, benzaldehyde, phenylacetaldehyde, α-phenylpropionaldehyde, β-phenylpropionaldehyde, benzaldehyde, 4-biphenylaldehyde, o-hydroxybenzaldehyde, m-hydroxybenzaldehyde, and p-hydroxybenzaldehyde. Examples include o-chlorobenzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, o-methylbenzaldehyde, m-methylbenzaldehyde, p-methylbenzaldehyde, p-ethylbenzaldehyde, 3,4-dimethylbenzaldehyde, pn-propylbenzaldehyde, pn-butylbenzaldehyde, terephthalaldehyde, 1-naphthaldehyde, 2-naphthaldehyde, and the like. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, acetophenone, and diphenyl ketone. These aldehydes and ketones may be used individually or in combination of two or more.

[0019] Among these, the novolac-type resin (A1) used in one aspect of the present invention is preferably a resin obtained by condensing cresol with aldehydes, more preferably a resin obtained by condensing at least one of metacresol and paracresol with at least one of formaldehyde and paraformaldehyde, and even more preferably a resin obtained by using metacresol and paracresol in combination and condensing them with at least one of formaldehyde and paraformaldehyde. When metacresol and paracresol are used in combination, the ratio of metacresol to paracresol [metacresol / paracresol] as raw materials is preferably 10 / 90 to 90 / 10 by mass, more preferably 20 / 80 to 80 / 20, and even more preferably 50 / 50 to 70 / 30.

[0020] In one aspect of the present invention, the novolac-type resin (A1) used may be a commercially available product such as "EP4080G" or "EP4050G" (both manufactured by Asahi Organic Chemicals Co., Ltd., and are cresol novolac resins).

[0021] The weight-average molecular weight (Mw) of the novolac-type resin (A1) used in one aspect of the present invention is preferably 500 to 30,000, more preferably 1,000 to 20,000, even more preferably 1,000 to 15,000, and even more preferably 1,000 to 10,000.

[0022] [Resin (A2)] The resin (A2) used in one aspect of the present invention is not particularly limited, and any known resin can be used, but it is desirable that the resin has at least one of a constituent unit (a2-1) derived from a phenolic hydroxyl group-containing compound and a constituent unit (a2-2) that can decompose by the action of an acid, base or heat to form an acidic functional group. It is more preferable that the resin is a copolymer having both constituent units (a2-1) and (a2-2). The resin has at least one of the constituent unit (a2-1) and the constituent unit (a2-2), which increases its solubility in alkaline developing solutions.

[0023] In the resin (A2) used in one aspect of the present invention, the total content ratio of constituent units (a2-1) and (a2-2) is preferably 30 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, and particularly preferably 80 mol% or more, relative to the total amount of constituent units of the resin (A2) (100 mol%).

[0024] Furthermore, if the resin (A2) used in one aspect of the present invention is a copolymer having both constituent units (a2-1) and (a2-2), the content ratio of constituent units (a2-1) to constituent units (a2-2) [(a2-1) / (a2-2)] is preferably 1 / 10 to 10 / 1, more preferably 1 / 5 to 8 / 1, even more preferably 1 / 2 to 6 / 1, and even more preferably 1 / 1 to 4 / 1 in molar ratio.

[0025] Examples of phenolic hydroxyl group-containing compounds that constitute the constituent unit (a2-1) include hydroxystyrene (o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene), isopropenylphenol (o-isopropenylphenol, m-isopropenylphenol, p-isopropenylphenol), and others, with hydroxystyrene being preferred.

[0026] Examples of acidic functional groups that can be formed by the decomposition of the constituent unit (a2-2) by the action of acid, base, or heat include phenolic hydroxyl groups and carboxyl groups. Examples of monomers that can form phenolic hydroxyl groups include p-(1-methoxyethoxy)styrene, p-(1-ethoxyethoxy)styrene, p-(1-n-propoxyethoxy)styrene, p-(1-i-propoxyethoxy)styrene, p-(1-cyclohexyloxyethoxy)styrene, and acetal-protected hydroxy(α-methyl)styrenes such as their α-methyl substituted derivatives; p-acetoxystyrene, t-butoxycarbonylstyrene, t-butoxystyrene, and their α-methyl substituted derivatives. These can be used individually or in combination of two or more.

[0027] Furthermore, examples of monomers that can form carboxyl groups include (meth)acrylates protected with acid-degradable ester groups, such as t-butyl (meth)acrylate, tetrahydropyranyl (meth)acrylate, 2-methoxybutyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-t-butoxycarbonylethyl (meth)acrylate, 2-benzyloxycarbonylethyl (meth)acrylate, 2-phenoxycarbonylethyl (meth)acrylate, 2-cyclohexyloxycarbonyl (meth)acrylate, 2-isobornyloxycarbonylethyl (meth)acrylate, and 2-tricyclodecanyloxycarbonylethyl (meth)acrylate. These can be used individually or in combination of two or more.

[0028] Among these, at least one monomer selected from t-butyl (meth)acrylate, tetrahydropyranyl (meth)acrylate, 2-cyclohexyloxycarbonylethyl (meth)acrylate, and p-(1-ethoxyethoxy)styrene is preferred as the monomer constituting the structural unit (a2-2).

[0029] The resin (A2) used in one aspect of the present invention may be any resin having at least one of the constituent unit (a2-1) and the constituent unit (a2-2) as described above, but it may also have other constituent units. Examples of monomers that constitute such other structural units include alkyl (meth)acrylates; hydroxyl group-containing monomers; epoxy group-containing monomers; alicyclic structure-containing monomers; olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and p-methoxystyrene; cyano group-containing vinyl monomers such as (meth)acrylonitrile and vinylidene cyanide; (meth)acrylamides such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N,N-dimethylol(meth)acrylamide; and heteroatom-containing alicyclic vinyl monomers such as (meth)acryloylmorpholine, N-vinylpyrrolidone, and N-vinylcaprolactam.

[0030] Examples of alkyl (meth)acrylates include compounds other than the monomers that constitute the constituent unit (a2-2), such as methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate (n-propyl (meth)acrylate, i-propyl (meth)acrylate).

[0031] Examples of the hydroxy-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The number of carbon atoms in the alkyl group of the hydroxyalkyl (meth)acrylates is preferably 1 to 10, more preferably 1 to 8, even more preferably 1 to 6, and even more preferably 2 to 4. The alkyl group may be a linear alkyl group or a branched alkyl group.

[0032] Examples of the epoxy-containing monomers include epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and 3-epoxycyclo-2-hydroxypropyl (meth)acrylate; glycidyl crotonate, allyl glycidyl ether, and the like.

[0033] Examples of monomers containing alicyclic structures include cycloalkyl(meth)acrylates such as cyclopropyl(meth)acrylate, cyclobutyl(meth)acrylate, cyclopentyl(meth)acrylate, cyclohexyl(meth)acrylate, cycloheptyl(meth)acrylate, and cyclooctyl(meth)acrylate, as well as isobornyl(meth)acrylate and dicyclopentenyl(meth)acrylate.

[0034] In one aspect of the present invention, the resin (A2) may be a resin having adamantyl (meth)acrylate-derived structural units as structural units derived from alicyclic structure-containing monomers. This resin corresponds to both resin (A2) and resin (A3) described later.

[0035] Furthermore, the resin (A2) used in one aspect of the present invention may have constituent units derived from monomers selected from compounds having two or more hydroxyl groups in their molecule, such as dihydric or polyhydric alcohols, polyether diols, and polyester diols, esters of (meth)acrylic acid, adducts of compounds having two or more epoxy groups in their molecule, such as epoxy resins, and (meth)acrylic acid, and condensates of compounds having two or more amino groups in their molecule and (meth)acrylic acid. Examples of such monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and pentaerythritol tri(meth)acrylate. Examples include polyalkylene glycol (derivative) di(meth)acrylates such as rilate, pentaerythritol tetra(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, N,N'-methylenebis(meth)acrylamide, and di(meth)acrylates of ethylene glycol adducts or propyl glycol adducts of bisphenol A, as well as epoxy(meth)acrylates such as (meth)acrylic acid adducts of bisphenol A diglycidyl ether.

[0036] The weight-average molecular weight (Mw) of the resin (A2) used in one aspect of the present invention is preferably 400 to 50,000, more preferably 1,000 to 40,000, even more preferably 1,000 to 30,000, and even more preferably 1,000 to 25,000.

[0037] [Resin (A3)] The resin (A3) used in one aspect of the present invention is not particularly limited, and any known resin may be used. A resin having a structural unit (a3-1) having an adamantane structure is used, but it is desirable that the structural unit can decompose by the action of an acid to form an acidic functional group. Furthermore, from the viewpoint of solubility in solvents and adhesion to substrates, it is practically preferable that the copolymer has structural units (a3-2) having a lactone structure together with structural unit (a3-1).

[0038] Furthermore, at least one of the hydrogen atoms to which the carbon atoms constituting the adamantane structure of the constituent unit (a3-1) are bonded may be substituted with a substituent R. Similarly, at least one of the hydrogen atoms to which the carbon atoms constituting the lactone structure of the constituent unit (a3-2) are bonded may also be substituted with a substituent R. Examples of the substituent R include C1-C6 alkyl groups, C1-C6 hydroxyalkyl groups, C3-C6 cycloalkyl groups, halogen atoms (fluorine, chlorine, bromine, iodine), deuterium atoms, hydroxyl groups, amino groups, nitro groups, cyano groups, and groups represented by the following formulas (i) or (ii).

[0039] [ka]

[0040] In formula (i) or (ii) above, R a and R b These are, independently, an alkyl group having 1 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 3 to 6 carbon atoms. m is an integer between 1 and 10, preferably between 1 and 6, more preferably between 1 and 3, and even more preferably between 1 and 2. A is an alkylene group having 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms, more preferably 2 to 3 carbon atoms). Examples of the alkylene group include methylene group, ethylene group, n-propylene group, i-propylene group, 1,4-butylene group, 1,3-butylene group, tetramethylene group, 1,5-pentylene group, 1,4-pentylene group, and 1,3-pentylene group.

[0041] In one embodiment of the present invention, the resin (A3) used contains a constituent unit (a3-1), which is a constituent unit (a3-1α) having an adamantane structure substituted with a hydroxyl group, and the content of this constituent unit (a3-1α) is preferably less than 50 mol%, more preferably less than 44 mol%, even more preferably less than 39 mol%, and even more preferably less than 34 mol%, relative to the total amount of constituent units (100 mol%) of the resin (A3).

[0042] In one embodiment of the present invention, the constituent unit (a3-1) is preferably a constituent unit (a3-1-1) represented by the following formula (a3-1-i) or a constituent unit (a3-1-2) represented by the following formula (a3-1-ii).

[0043] [ka]

[0044] In the above formula, n is an integer between 0 and 14, preferably between 0 and 4, more preferably between 0 and 2, and even more preferably between 0 and 1. R x Each of these is independently either a hydrogen atom or a methyl group. Each R is independently a substituent R that the adamantane structure may have, and specifically as described above, but is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. X 1 Each of these is independently a single bond, an alkylene group having 1 to 6 carbon atoms, or a divalent linking group represented by any of the following formulas.

[0045] [ka] In the above formula, *1 indicates the bond position with the oxygen atom in formula (a3-1-i) or (a3-1-ii), and *2 indicates the bond position with the carbon atom of the adamantane structure. 1 This represents an alkylene group having 1 to 6 carbon atoms.

[0046] Furthermore, in one embodiment of the present invention, it is preferable that the constituent unit (a3-2) is any of the constituent unit (a3-2-1) represented by the following formula (a3-2-i), the constituent unit (a3-2-2) represented by the following formula (a3-2-ii), and the constituent unit (a3-2-3) represented by the following formula (a3-2-iii).

[0047] [ka]

[0048] In the above formula, n1 is an integer from 0 to 5, preferably an integer from 0 to 2, more preferably an integer from 0 to 1. n2 is an integer from 0 to 9, preferably an integer from 0 to 2, more preferably an integer from 0 to 1. n3 is an integer from 0 to 9, preferably an integer from 0 to 2, more preferably an integer from 0 to 1. R y is a hydrogen atom or a methyl group. Each R is independently a substituent R which may have a lactone structure, specifically as described above, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. When there are a plurality of Rs, the plurality of Rs may be the same group or different groups from each other. X 2 is a single bond, an alkylene group having 1 to 6 carbon atoms, or a divalent linking group represented by any of the following formulas.

[0049]

Chemical formula

[0050] Note that the resin (A3) used in one aspect of the present invention may have other constitutional units in addition to the constitutional units (a3-1) and (a3-2). Other such constituent units include alkyl (meth)acrylates; hydroxyl group-containing monomers; epoxy group-containing monomers; alicyclic structure-containing monomers; olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; and constituent units derived from monomers such as styrene, α-methylstyrene, vinyltoluene, acrylonitrile, (meth)acrylamide, (meth)acrylonitrile, (meth)acryloylmorpholine, and N-vinylpyrrolidone. Details of these monomers are the same as those described in the section on resins (A2).

[0051] In the resin (A3) used in one aspect of the present invention, the total content of constituent units (a3-1) and (a3-2) is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, even more preferably 70 to 100 mol%, even more preferably 80 to 100 mol%, and particularly preferably 90 to 100 mol%, relative to the total amount (100 mol%) of constituent units of the resin (A3).

[0052] The weight-average molecular weight (Mw) of the resin (A3) used in one aspect of the present invention is preferably 400 to 50,000, more preferably 2,000 to 40,000, even more preferably 3,000 to 30,000, and even more preferably 4,000 to 20,000. The molecular weight distribution (Mw / Mn) of the resin (A3) is preferably 6.0 or less, more preferably 5.0 or less, even more preferably 4.0 or less, and even more preferably 3.2 or less, and also preferably 1.01 or more, more preferably 1.05 or more, and even more preferably 1.1 or more.

[0053] [Resin (A4)] The resin (A4) used in one aspect of the present invention is not particularly limited as long as it has two or more constituent units from among a phenolic hydroxyl group-containing compound (a2-1), a constituent unit that can decompose by the action of acid, base or heat to form an acidic functional group (a2-2), a constituent unit having an adamantane structure (a3-1), and a constituent unit having a lactone structure (a3-2) (excluding resins (A2) and resins (A3)), and known resins can be used. For example, resins listed in the book "40 Years of Lithography Technology," International Patent Publication No. 2014-175275, International Patent Publication No. 2015-115613, International Patent Publication No. 2020-137935, International Patent Publication No. 2021-029395, and International Patent Publication No. 2021-029396 can be used.

[0054] The weight-average molecular weight (Mw) of the resin (A4) used in one aspect of the present invention is preferably 400 to 50,000, more preferably 2,000 to 40,000, even more preferably 3,000 to 30,000, and even more preferably 4,000 to 20,000. The molecular weight distribution (Mw / Mn) of the resin (A4) is preferably 6.0 or less, more preferably 5.0 or less, even more preferably 4.0 or less, and even more preferably 3.2 or less, and also preferably 1.01 or more, more preferably 1.05 or more, and even more preferably 1.1 or more.

[0055] <Component (B): Solvent> A resist composition according to one aspect of the present invention contains a solvent (B) comprising a compound (B1) represented by the following general formula (b-1). Compound (B1) may be used alone, or two or more compounds may be used in combination.

[0056] [ka]

[0057] In the above equation (b-1), R 1 This is an alkyl group having 1 to 10 carbon atoms. This alkyl group may be a linear alkyl group or a branched alkyl group. R 1 Examples of alkyl groups that can be selected include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, or t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, and the like.

[0058] Among these, in one embodiment of the present invention, R in the general formula (b-1) 1 The group is preferably a methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, or t-butyl group; more preferably an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, or t-butyl group; even more preferably an n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, or t-butyl group; and even more preferably an i-propyl group, n-butyl group, or i-butyl group.

[0059] Furthermore, in a resist composition according to one embodiment of the present invention, it is preferable to include a solvent (B2) other than compound (B1) as component (B). Examples of solvents (B2) include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having ester bonds such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, and monobutyl ether, or compounds having ether bonds such as monophenyl ether; Examples include cyclic ethers such as dioxane, and esters other than compounds (B1) such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl α-methoxyisobutyrate, methyl β-methoxyisobutyrate, ethyl 2-ethoxyisobutyrate, methyl methoxypropionate, ethyl ethoxypropionate, methyl α-formyloxyisobutyrate, methyl β-formyloxyisobutyrate, and methyl 3-hydroxyisobutyrate; aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenethole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene; and dimethyl sulfoxide (DMSO). These solvents (B2) may be used individually or in combination of two or more.

[0060] However, from the viewpoint of providing a photoresist material capable of forming a thick resist film, in the resist composition of the present invention, the content ratio of compound (B1) in component (B) is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, even more preferably 50 to 100% by mass, even more preferably 60 to 100% by mass, and particularly preferably 70 to 100% by mass, based on the total amount (100% by mass) of component (B) contained in the resist composition.

[0061] In one aspect of the present invention, component (B) used as a solvent (B2) preferably contains one or more selected from the group consisting of methyl α-methoxyisobutyrate, methyl α-formyloxyisobutyrate, methyl α-acetyloxyisobutyrate, methyl 3-hydroxyisobutyrate, and 1-methoxy-2-propanol, from the viewpoint of solubility of the acid generator used in the resist composition. The inclusion of methyl α-methoxyisobutyrate is preferable from the viewpoint of solubility of the resin used in the resist composition. The inclusion of methyl α-formyloxyisobutyrate and methyl α-acetyloxyisobutyrate is preferable from the viewpoint of solubility of the resin used in the resist composition and thickening of the resist film. The inclusion of methyl 3-hydroxyisobutyrate is preferable from the viewpoint of obtaining a rectangular resist pattern. The inclusion of 1-methoxy-2-propanol is preferable from the viewpoint of obtaining a resist film with high in-plane uniformity. The method of mixing α-methyl methoxyisobutyrate, α-formyloxyisobutyrate, α-acetyloxyisobutyrate, 3-hydroxyisobutyrate, or 1-methoxy-2-propanol is not particularly limited, but it can be included by either adding α-methyl methoxyisobutyrate, α-formyloxyisobutyrate, 3-hydroxyisobutyrate, or 1-methoxy-2-propanol to compound (B1), or by producing or incorporating them as a by-product during the manufacturing process of compound (B1).

[0062] The solvent (B2) content is not limited, but based on the total amount of compound (B1) (100% by mass), it is preferably less than 100% by mass from the viewpoint of improving productivity by shortening the drying time of the coated film, more preferably 70% by mass or less, more preferably 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, and 1% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.01% by mass or less, from the viewpoint of increasing the dissolving power of the solvent while ensuring an appropriate drying time. From the viewpoint of improving the storage stability of the resist composition, it is preferably 0.0001% by mass or more, more preferably 0.001% by mass or more from the viewpoint of improving the solubility of the active ingredients of the resist composition, and more preferably 0.01% by mass or more from the viewpoint of suppressing defects in the resist film.

[0063] The content of α-methyl methoxyisobutyrate, α-formyloxyisobutyrate, α-acetyloxyisobutyrate, 3-hydroxyisobutyrate, or 1-methoxy-2-propanol is not limited, but based on the total amount (100% by mass) of the resist composition, it is preferably less than 100% by mass from the viewpoint of improving productivity by shortening the drying time of the coated film, more preferably 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, and 1% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.01% by mass or less. From the viewpoint of improving the storage stability of the resist composition, it is preferably 0.0001% by mass or more, from the viewpoint of improving the solubility of the active ingredients of the resist composition, and even more preferably 0.01% by mass or more from the viewpoint of suppressing defects in the resist film.

[0064] The content of α-methyl methoxyisobutyrate, α-formyloxyisobutyrate, α-acetyloxyisobutyrate, 3-hydroxyisobutyrate, or 1-methoxy-2-propanol is preferably 100% by mass or less, based on the total amount (100% by mass) of compound (B1), more preferably 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, and 1% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.01% by mass or less. From the viewpoint of improving the storage stability of the resist composition, 0.0001% by mass or more is preferred, from the viewpoint of improving the solubility of the active ingredients of the resist composition, and even more preferably 0.01% by mass or more is preferred.

[0065] Furthermore, from the viewpoint of in-plane uniformity of the coated film, the content of 1-methoxy-2-propanol is preferably 1 to 98% by mass, and more preferably 16 to 98% by mass, based on the total amount (100% by mass) of the resist composition. Furthermore, it is also preferably 1 to 99% by mass, and more preferably 30 to 99% by mass, based on the total amount (100% by mass) of compound (B1).

[0066] In one embodiment of the present invention, component (B) may also preferably include one or more selected from the group consisting of methyl α-formyloxyisobutyrate, methyl α-acetyloxyisobutyrate, and methyl 3-hydroxyisobutyrate as the solvent (B2).

[0067] In the resist composition of the present invention, the content of component (B) is set appropriately depending on the application, but can be 50% by mass or more, 54% by mass or more, 58% by mass or more, 60% by mass or more, 65% by mass or more, 69% by mass or more, 74% by mass or more, 77% by mass or more, 80% by mass or more, 82% by mass or more, 84% by mass or more, 88% by mass or more, 90% by mass or more, 94% by mass or more, or 97% by mass or more, based on the total amount (100% by mass) of the resist composition. Furthermore, the upper limit for the content of component (B) is set appropriately in accordance with the content of component (A), but it can be 99% by mass or less, 98% by mass or less, 96% by mass or less, 93% by mass or less, 91% by mass or less, 86% by mass or less, 81% by mass or less, 76% by mass or less, 71% by mass or less, 66% by mass or less, or 61% by mass or less, based on the total amount (100% by mass) of the resist composition. Furthermore, the content of component (B) can be specified in any combination by appropriately selecting from the upper and lower limit options mentioned above.

[0068] <Ingredients (C): Additives selected from photosensitive agents and acid generators> A resist composition according to one aspect of the present invention preferably contains at least one additive (C) selected from a photosensitive agent and an acid generator. In addition, component (C) may be used alone or in combination of two or more components. In a resist composition according to one embodiment of the present invention, the content of component (C) is preferably 0.01 to 80 parts by mass, more preferably 0.05 to 65 parts by mass, even more preferably 0.1 to 50 parts by mass, and even more preferably 0.5 to 30 parts by mass, based on 100 parts by mass of resin (A) contained in the resist composition. The following describes the photosensitive agent and acid generator included as component (C).

[0069] [Photosensitive agent] The photosensitive agent that can be selected as component (C) is not particularly limited as long as it is commonly used as a photosensitive component in positive-type resist compositions. Photosensitive agents may be used alone or in combination of two or more types.

[0070] Examples of photosensitive agents used in one aspect of the present invention include reaction products of an acid chloride and a compound having a functional group (such as a hydroxyl group or an amino group) that can condense with the acid chloride. Examples of acid chlorides include naphthoquinone diazide sulfonate chloride and benzoquinone diazide sulfonate chloride, specifically 1,2-naphthoquinone diazide-5-sulfonyl chloride and 1,2-naphthoquinone diazide-4-sulfonyl chloride. Compounds that can condense with functional acid chlorides include, for example, hydroquinone, resorcinol, 2,4-dihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2',3,4,6'-pentahydroxybenzophenone, and other hydroxybenzophenone compounds. Examples include hydroxyphenylalkanes such as zophenones, bis(2,4-dihydroxyphenyl)methane, bis(2,3,4-trihydroxyphenyl)methane, and bis(2,4-dihydroxyphenyl)propane, and hydroxytriphenylmethanes such as 4,4',3”,4”-tetrahydroxy-3,5,3',5'-tetramethyltriphenylmethane and 4,4',2”,3”,4”-pentahydroxy-3,5,3',5'-tetramethyltriphenylmethane. In addition, the photosensitive agent used in one aspect of the present invention may be a commercially available product such as "DTEP-350" (manufactured by Daito Chemix Co., Ltd., a diazonaphthoquinone-type photosensitive agent).

[0071] [Acid Generator] The acid generator that can be selected as component (C) is any compound that can directly or indirectly generate acid by irradiation with radiation such as visible light, ultraviolet light, excimer laser, electron beam, extreme ultraviolet (EUV), X-ray, and ion beam. Specifically, preferred acid generators are compounds represented by any of the following general formulas (c-1) to (c-8).

[0072] (Compounds represented by general formula (c-1)) [ka]

[0073] In the above equation (c-1), R 13 Each of these is independently a hydrogen atom, a linear, branched, or cyclic alkyl group, a linear, branched, or cyclic alkoxy group, a hydroxyl group, or a halogen atom. X - This is a sulfonic acid ion or halide ion having an alkyl group, an aryl group, a halogen-substituted alkyl group, or a halogen-substituted aryl group.

[0074] The compounds represented by the general formula (c-1) include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, diphenyltolylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, diphenyl-4-methylphenylsulfonium trifluoromethanesulfonate, di-2,4,6-trimethylphenylsulfonium trifluoromethanesulfonate, diphenyl-4-t-butoxyphenylsulfonium trifluoromethanesulfonate, diphenyl-4-t-butoxyphenylsulfonium nonafluoro-n-butanesulfonate, diphenyl-4-hydroxyphenylsulfonium trifluoromethanesulfonate, bis(4-fluorophenyl)-4-hydroxyphenylsulfonium trifluoromethanesulfonate, diphenyl-4-hydroxyphenylsulfonium nonafluoro-n-butanesulfonate, bis(4-hydroxyphenyl)-phenylsulfonium trifluoromethanesulfonate, and tri(4-methylphenylsulfonate). Toxyphenyl)sulfonium trifluoromethanesulfonate, tri(4-fluorophenyl)sulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium benzenesulfonate, diphenyl-2,4,6-trimethylphenyl-p-toluenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium-2-trifluoromethylbenzenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium-4-trifluoromethylbenzenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium-2,4-difluorobenzenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium hexafluorobenzenesulfonate, diphenylnaphthylsulfonium trifluoromethanesulfonate, diphenyl-4-hydroxyphenylsulfonium-p-toluenesulfonate, triphenylsulfonium 10-camphorsulfonate, diphenyl-4-hydroxyphenylsulfonium 10-camphorsulfonate, and cyclo(1,Preferably, it is at least one selected from the group consisting of 3-perfluoropropanedisulfone)imidate.

[0075] (Compounds represented by general formula (c-2)) [ka]

[0076] In the above equation (c-2), R 14 Each of these is independently a hydrogen atom, a linear, branched, or cyclic alkyl group, a linear, branched, or cyclic alkoxy group, a hydroxyl group, or a halogen atom. X - This is a sulfonic acid ion or halide ion having an alkyl group, an aryl group, a halogen-substituted alkyl group, or a halogen-substituted aryl group.

[0077] The compounds represented by the general formula (c-2) include bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate, bis(4-t-butylphenyl)iodonium nonafluoro-n-butanesulfonate, bis(4-t-butylphenyl)iodonium perfluoro-n-octanesulfonate, bis(4-t-butylphenyl)iodonium p-toluenesulfonate, bis(4-t-butylphenyl)iodonium benzenesulfonate, and bis(4-t-butylphenyl)iodonium-2-trifluoromethylben Zensulfonate, bis(4-t-butylphenyl)iodonium-4-trifluoromethylbenzenesulfonate, bis(4-t-butylphenyl)iodonium-2,4-difluorobenzenesulfonate, bis(4-t-butylphenyl)iodonium-hexafluorobenzenesulfonate, bis(4-t-butylphenyl)iodonium-10-camphor sulfonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluorinated Preferably, it is at least one selected from the group consisting of r-n-octanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium benzenesulfonate, diphenyliodonium 10-camphorsulfonate, diphenyliodonium-2-trifluoromethylbenzenesulfonate, diphenyliodonium-4-trifluoromethylbenzenesulfonate, diphenyliodonium-2,4-difluorobenzenesulfonate, diphenyliodonium hexafluorobenzenesulfonate, di(4-trifluoromethylphenyl)iodonium trifluoromethanesulfonate, di(4-trifluoromethylphenyl)iodonium nonafluoro-n-butanesulfonate, di(4-trifluoromethylphenyl)iodonium perfluoro-n-octanesulfonate, di(4-trifluoromethylphenyl)iodonium p-toluenesulfonate, di(4-trifluoromethylphenyl)iodonium benzenesulfonate, and di(4-trifluoromethylphenyl)iodonium 10-camphorsulfonate.

[0078] (Compounds represented by the general formula (c-3)) [ka]

[0079] In the above formula (c-3), Q is an alkylene group, an arylene group, or an alkoxylene group. 15 This is an alkyl group, an aryl group, a halogen-substituted alkyl group, or a halogen-substituted aryl group.

[0080] The compounds represented by the general formula (c-3) include N-(trifluoromethylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(trifluoromethylsulfonyloxy)naphthylimide, N-(10-camphorsulfonyloxy)succinimide, and N-(10-camphorsulfonyloxy)phthalimide. , N-(10-camphorsulfonyloxy)diphenylmaleimide, N-(10-camphorsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(10-camphorsulfonyloxy)naphthylimide, N-(n-octanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(n-octanesulfonyloxy)naphthylimide, N-(p-toluenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(p-to N-(2-trifluoromethylbenzenesulfonyloxy)naphthylimide, N-(2-trifluoromethylbenzenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(2-trifluoromethylbenzenesulfonyloxy)naphthylimide, N-(4-trifluoromethylbenzenesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, N-(4-trifluoromethylbenzenesulfonyloxy)naphthylimide, N-(perfluorobenzenesulfonyloxy)bicyclo[2.2.1]hept-5 -en-2,3-dicarboximide, N-(perfluorobenzenesulfonyloxy)naphthylimide, N-(1-naphthalenesulfonyloxy)bicyclo[2.2.1]hept-5-en-2,3-dicarboximide, N-(1-naphthalenesulfonyloxy)naphthylimide, N-(nonafluoro-n-butanesulfonyloxy)bicyclo[2.2.1]hept-5-en-2,3-dicarboximide, N-(nonafluoro-n-butanesulfonyloxy)naphthylimide, N-(perfluoro-n-octanesulfonyloxy)bicyclo[2.2.1] Preferably, it is at least one selected from the group consisting of hept-5-ene-2,3-dicarboximide and N-(perfluoro-n-octanesulfonyloxy)naphthylimide.

[0081] (Compounds represented by the general formula (c-4)) [ka]

[0082] In the above equation (c-4), R 16 Each of these is independently a linear, branched, or cyclic alkyl group, aryl group, heteroaryl group, or aralkyl group, wherein at least one hydrogen of these groups may be substituted with any substituent.

[0083] The compound represented by the general formula (c-4) is preferably at least one selected from the group consisting of diphenyldisulfone, di(4-methylphenyl)disulfone, dinaphthyldisulfone, di(4-t-butylphenyl)disulfone, di(4-hydroxyphenyl)disulfone, di(3-hydroxynaphthyl)disulfone, di(4-fluorophenyl)disulfone, di(2-fluorophenyl)disulfone, and di(4-tolufluoromethylphenyl)disulfone.

[0084] (Compounds represented by the general formula (c-5)) [ka]

[0085] In the above equation (c-5), R 17 Each of these is independently a linear, branched, or cyclic alkyl group, aryl group, heteroaryl group, or aralkyl group, wherein at least one hydrogen of these groups may be substituted with any substituent.

[0086] The compound represented by the general formula (c-5) is preferably at least one selected from the group consisting of α-(methylsulfonyloxyimino)-phenylacetonitrile, α-(methylsulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(trifluoromethylsulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(ethylsulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(propylsulfonyloxyimino)-4-methylphenylacetonitrile, and α-(methylsulfonyloxyimino)-4-bromophenylacetonitrile.

[0087] (Compounds represented by the general formula (c-6)) [ka]

[0088] In the above equation (c-6), R 18 Each of these is an alkyl halide having one or more chlorine atoms and one or more bromine atoms independently. The number of carbon atoms in the alkyl halide is preferably 1 to 5.

[0089] (Compounds represented by general formulas (c-7) and (c-8)) [ka]

[0090] In the above equations (c-7) and (c-8), R 19 and R 20 Each of these is independently a C1-C3 alkyl group (methyl group, ethyl group, n-propyl group, i-propyl group, etc.), a C3-C6 cycloalkyl group (cyclopentyl group, cyclohexyl group, etc.), a C1-C3 alkoxyl group (methoxy group, ethoxy group, propoxy group, etc.), or a C6-C10 aryl group (phenyl group, toluyl group, naphthyl group), with a C6-C10 aryl group being preferred. L19 and L 20 Each of these is an organic group having a 1,2-naphthoquinone diazide group, and specifically, 1,2-quinone diazide sulfonyl groups such as 1,2-naphthoquinone diazide-4-sulfonyl group, 1,2-naphthoquinone diazide-5-sulfonyl group, and 1,2-naphthoquinone diazide-6-sulfonyl group are preferred, with 1,2-naphthoquinone diazide-4-sulfonyl group or 1,2-naphthoquinone diazide-5-sulfonyl group being more preferred. p is an integer between 1 and 3, q ​​is an integer between 0 and 4, and 1 ≤ p + q ≤ 5. J 19 These are single bonds, alkylene groups with 1 to 4 carbon atoms, cycloalkylene groups with 3 to 6 carbon atoms, phenylene groups, groups represented by the following formula (c-7-i), carbonyl groups, ester groups, amide groups, or -O-. Y 19 X is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. 20 These are each independent groups represented by the following formula (c-8-i).

[0091] [ka]

[0092] In the above equation (c-8-i), Z 22 Each of these is independently an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. 22 Each of these is independently an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an alkoxyl group having 1 to 6 carbon atoms, and r is an integer from 0 to 3.

[0093] In one aspect of the present invention, other acid generators other than compounds represented by any of the above general formulas (c-1) to (c-8) may be used as the acid generator. Other acid generators include, for example, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylphenylsulfonyl)diazomethane, bis(tert-butylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane, bis(isobutylsulfonyl)diazomethane, bis(isopropylsulfonyl)diazomethane, bis(n-propylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(isopropylsulfonyl)diazomethane, 1,3-bis(cyclohexylsulfonylazomethylsulfonyl)propane, and 1,4-bis(phenyl Examples include bissulfonyl diazomethanes such as sulfonylazomethylsulfonyl)butane, 1,6-bis(phenylsulfonylazomethylsulfonyl)hexane, and 1,10-bis(cyclohexylsulfonylazomethylsulfonyl)decane, as well as halogen-containing triazine derivatives such as 2-(4-methoxyphenyl)-4,6-(bistrichloromethyl)-1,3,5-triazine, 2-(4-methoxynaphthyl)-4,6-(bistrichloromethyl)-1,3,5-triazine, tris(2,3-dibromopropyl)-1,3,5-triazine, and tris(2,3-dibromopropyl) isocyanurate.

[0094] <Other additives> A resist composition according to one aspect of the present invention may contain components other than those described above (A) to (C). Other components include, for example, one or more selected from acid crosslinking agents, acid diffusion control agents, dissolution accelerators, dissolution control agents, sensitizers, surfactants, organic carboxylic acids or phosphorus oxoacids or their derivatives. The content of each of these other components is appropriately selected depending on the type of component and the type of resin (A), but is preferably 0.001 to 100 parts by mass, more preferably 0.01 to 70 parts by mass, even more preferably 0.1 to 50 parts by mass, and even more preferably 0.3 to 30 parts by mass per 100 parts by mass of resin (A) contained in the resist composition.

[0095] (Acid crosslinking agent) The acid crosslinking agent can be any compound having a crosslinkable group that can crosslink with resin (A), and can be appropriately selected depending on the type of resin (A). Examples of acid crosslinking agents used in one aspect of the present invention include methylol group-containing compounds such as methylol group-containing melamine compounds, methylol group-containing benzoguanamine compounds, methylol group-containing urea compounds, methylol group-containing glycoluryl compounds, and methylol group-containing phenol compounds; alkoxyalkyl group-containing compounds such as alkoxyalkyl group-containing melamine compounds, alkoxyalkyl group-containing benzoguanamine compounds, alkoxyalkyl group-containing urea compounds, alkoxyalkyl group-containing glycoluryl compounds, and alkoxyalkyl group-containing phenol compounds; carboxymethyl group-containing compounds such as carboxymethyl group-containing melamine compounds, carboxymethyl group-containing benzoguanamine compounds, carboxymethyl group-containing urea compounds, carboxymethyl group-containing glycoluryl compounds, and carboxymethyl group-containing phenol compounds; and epoxy compounds such as bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, novolac resin type epoxy compounds, resol resin type epoxy compounds, and poly(hydroxystyrene) type epoxy compounds. These acid crosslinking agents may be used individually or in combination of two or more.

[0096] (Acid diffusion control agent) Acid diffusion control agents are additives that control the diffusion of acids generated from acid generators by radiation irradiation within the resist film, thereby preventing undesirable chemical reactions in unexposed areas. The acid diffusion control agent used in one aspect of the present invention is not particularly limited, but examples include radiodegradable basic compounds such as nitrogen atom-containing basic compounds, basic sulfonium compounds, and basic iodonium compounds. These acid diffusion control agents may be used individually or in combination of two or more.

[0097] (Dissolution accelerator) The dissolution accelerator is an additive that enhances the solubility of resin (A) in the developer and moderately increases the dissolution rate of resin (A) during development. There are no particular limitations on the dissolution accelerator used in one aspect of the present invention, but examples include bisphenols, phenolic compounds such as tris(hydroxyphenyl)methane, and the like. These dissolution accelerators may be used individually or in combination of two or more.

[0098] (Soluble control agent) A dissolution control agent is an additive that controls the solubility of resin (A) in the developer when its solubility is too high, thereby moderately reducing the dissolution rate during development. There are no particular limitations on the dissolution control agent used in one aspect of the present invention, but examples include aromatic hydrocarbons such as phenanthrene, anthracene, and acenaphthene; ketones such as acetophenone, benzophenone, and phenylnaphthylketone; and sulfones such as methylphenylsulfone, diphenylsulfone, and dinaphthylsulfone. These dissolution control agents may be used individually or in combination of two or more.

[0099] (Sensitizer) A sensitizer is an additive that absorbs the energy of irradiated radiation and transfers that energy to an acid generator, thereby increasing the amount of acid produced, and can improve the apparent sensitivity of the resist. Examples of sensitizers used in one aspect of the present invention include benzophenones, biacetyls, pyrenes, phenothiazines, fluorenes, and the like. These sensitizers may be used individually or in combination of two or more.

[0100] (Surfactants) Surfactants are additives that improve the coatability, striation properties, and developability of resist compositions. The surfactant used in one aspect of the present invention may be any of anionic surfactants, cationic surfactants, nonionic surfactants, or amphoteric surfactants, but nonionic surfactants are preferred. Examples of nonionic surfactants include polyoxyethylene higher alkyl ethers, polyoxyethylene higher alkylphenyl ethers, and polyethylene glycol higher fatty acid diesters. These surfactants may be used individually or in combination of two or more types.

[0101] (Organic carboxylic acids or phosphorus oxoacids or their derivatives) Organic carboxylic acids, phosphorus oxoacids, or their derivatives are additives that have the effect of preventing sensitivity degradation or improving resist pattern shape, settling stability, etc. There are no particular limitations on the organic carboxylic acid used in one aspect of the present invention, but examples include malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, etc. Examples of phosphorus oxoacids or derivatives thereof include phosphoric acid, di-n-butyl phosphate, diphenyl phosphate, and other phosphoric acid derivatives or their esters, phosphonic acid or its ester derivatives, such as phosphonic acid, dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate, and phosphinic acid and its ester derivatives, such as phosphinic acid and phenylphosphinic acid. These can be used individually, or two or more can be used in combination.

[0102] (Other ingredients) Furthermore, a resist composition according to one embodiment of the present invention may also contain, in addition to the other components mentioned above, dyes, pigments, adhesion aids, anti-halation agents, preservative stabilizers, defoaming agents, shape modifiers, and the like.

[0103] [Method for forming a resist film] As described above, the resist composition according to one aspect of the present invention can form a thick resist film suitable for the manufacture of various devices, even though the content of the active ingredient including the resin is limited to below a predetermined value. There are no particular restrictions on the method for forming the resist film, but for example, a method having the following step (1) is possible, and a method having further steps (2) to (3) is preferable. Step (1): A step of applying the resist composition according to one embodiment of the present invention described above onto a substrate to form a coating film. • Step (2): A step that involves heat treatment after step (1). • Step (3): Step to form a resist pattern.

[0104] <Process (1)> In step (1), there are no particular restrictions on the substrate on which the coating film is formed. Examples include electronic component substrates and substrates on which a predetermined wiring pattern is formed. More specifically, examples include silicon wafers, metal substrates such as copper, chromium, iron, and aluminum, and glass substrates. There are no particular restrictions on the material of the wiring pattern, but examples include copper, aluminum, nickel, and gold.

[0105] In addition, the substrate used in one aspect of the present invention may, if necessary, have an underlayer film formed from a material selected from organic and inorganic materials on the surface on which the coating film is formed. When such an underlayer film substrate is used, the coating film is formed on the underlayer film. Examples of materials used to form the underlying film include the underlying film-forming composition described in International Publication No. 2016 / 021511.

[0106] In one embodiment of the present invention, the substrate may be surface-treated by applying a pre-wetting agent to the surface on which the coating film is formed, if necessary. Generally, a considerable amount of resist composition is scattered from the outer periphery, where the peripheral speed is significantly higher than at the center, leading to increased consumption of the resist composition. To address this problem, applying a pre-wetting agent to the substrate surface makes it easier for the resist composition to diffuse on the substrate, thereby reducing the amount of resist composition that needs to be supplied. Examples of pre-wetting agents include cyclohexanone, ethyl lactate, and methyl-3-methoxypropinate. There are no particular limitations on the specific surface treatment method using a pre-wetting agent, but for example, the method described in Japanese Patent Publication No. 2004-39828 can be cited.

[0107] As a coating method for applying the resist composition onto the substrate, known methods can be appropriately applied, such as rotary coating, casting coating, and roll coating. As described above, the resist composition according to one aspect of the present invention can form a thick coating film by these coating methods.

[0108] <Process (2)> In one embodiment of the present invention, it is preferable to perform a heat treatment as step (2) after step (1). By performing the heat treatment, the adhesion between the substrate and the resist film can be improved. The heating temperature for the heat treatment in this process is set appropriately according to the composition of the resist composition, but is preferably 20 to 250°C, more preferably 20 to 150°C.

[0109] <Process (3)> Step (3) is a step in which the formed resist film is exposed through a desired mask pattern to form a predetermined resist pattern. Examples of radiation used during exposure include visible light, ultraviolet light such as g-rays (wavelength 436 nm) and i-rays (wavelength 365 nm), far-ultraviolet light such as ArF excimer lasers (wavelength 193 nm) and KrF excimer lasers (wavelength 248 nm), excimer lasers, electron beams, extreme ultraviolet (EUV), X-rays such as synchrotron radiation, and ion beams. From the viewpoint of stably forming high-precision fine patterns in exposure, it is preferable to perform heat treatment after radiation irradiation. The heating temperature for this heat treatment is preferably 20 to 250°C, more preferably 20 to 150°C.

[0110] Next, the exposed resist film can be developed with a developer to form a predetermined resist pattern. As the developer used, it is preferable to select a solvent with a solubility parameter (SP value) close to that of the resin (A) contained in the resist composition. Examples include polar solvents such as ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents, hydrocarbon solvents, or alkaline aqueous solutions. Examples of alkaline compounds contained in the alkaline aqueous solution include mono-, di-, or tri-alkylamines; mono-, di-, or tri-alkanolamines; heterocyclic amines; tetraalkylammonium hydroxides; choline; 1,8-diazabicyclo[5,4,0]-7-undecene, 1,5-diazabicyclo[4,3,0]-5-nonene, etc.

[0111] Examples of development methods include immersing the substrate in a tank filled with developer solution for a certain period of time (dip method), developing by puddling the developer solution onto the substrate surface using surface tension and leaving it still for a certain period of time (paddle method), spraying the developer solution onto the substrate surface (spray method), and continuously dispensing the developer solution onto a substrate rotating at a constant speed while scanning the nozzle at a constant speed (dynamic dispensing method). Furthermore, while there are no particular restrictions on the development time, it is preferably between 10 and 90 seconds.

[0112] After development, a step may be performed to stop development while replacing the solvent with another solvent. Furthermore, after development, it is preferable to perform a washing step using a rinsing solution containing an organic solvent. As for the rinsing solution used in the rinsing step after development, there are no particular restrictions as long as it does not dissolve the formed resist pattern, and a general organic solvent solution or water can be used. It is preferable to use a rinsing solution that contains at least one organic solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents. There are no particular restrictions on the duration of the rinsing process, but it is preferably 10 to 90 seconds.

[0113] In the rinsing process, the developed substrate is cleaned using a rinsing solution containing the aforementioned organic solvent. The cleaning method is not particularly limited, but examples include a method in which the rinsing solution is continuously applied to a substrate rotating at a constant speed (rotary coating method), a method in which the substrate is immersed in a tank filled with rinsing solution for a certain period of time (dip method), and a method in which the rinsing solution is sprayed onto the surface of the substrate (spray method).

[0114] A patterned wiring substrate is obtained by etching after forming a resist pattern. The etching method can be any known method, such as dry etching using plasma gas or wet etching using an alkaline solution, cupric chloride solution, or ferric chloride solution. Plating may be performed after the resist pattern has been formed. The plating method is not particularly limited, but examples include copper plating, solder plating, nickel plating, and gold plating.

[0115] The remaining resist pattern after etching can be removed with an organic solvent. The organic solvent is not particularly limited, but examples include PGMEA (propylene glycol monomethyl ether acetate), PGME (propylene glycol monomethyl ether), and EL (ethyl lactate). The stripping method is not particularly limited, but examples include immersion methods and spray methods. The wiring substrate on which the resist pattern is formed may be a multilayer wiring substrate and may have small-diameter through-holes. In this embodiment, the wiring substrate can also be formed by a method in which a resist pattern is formed, a metal is deposited in a vacuum, and then the resist pattern is dissolved in a solution, i.e., the lift-off method. [Examples]

[0116] The present invention will be described below with reference to examples, but the present invention is not limited in any way to these examples. The measurements in the examples were taken using the following methods or apparatus.

[0117] (1) Film thickness of the coating The film thickness of the coating formed from the resist composition was measured using a film thickness measurement system (device name "F20", manufactured by Filmetrics) in a constant temperature and humidity chamber at 23°C and 50% humidity (relative humidity).

[0118] (2) Content ratio of constituent units of the resin The content ratio of the constituent units of the resin is, 13 Using 1C-NMR (model "JNM-ECA500", manufactured by JEOL Ltd., 125MHz), deuterated chloroform was used as the solvent. 13 Measurements were taken by performing 1024 cumulative operations in quantitative mode C.

[0119] (3) Weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the resin. The Mw and Mn of the resin were measured using gel permitting chromatography (GPC) under the following conditions, with polystyrene as the standard substance. • Device name: Hitachi LaChrom series • Detector: RI detector L-2490 • Columns: Two TSKgelGMHHR-M columns manufactured by Tosoh Corporation + Guard column HHR-H • Solvent: THF (containing stabilizer) ·Flow rate 1mL / min Column temperature: 40°C Then, the ratio of Mw to Mn [Mw / Mn] of the resin was calculated and used as the molecular weight distribution value of the resin.

[0120] The solvents used in the following examples and comparative examples are as follows: <Ingredient (B1)> · HBM: 2-hydroxyisobutyrate methyl, in the above general formula (b-1), R 1 A compound in which the group is a methyl group. • iPHIB: Isopropyl 2-hydroxyisobutyrate, in the above general formula (b-1), R 1 A compound in which the group is i-propyl. • iBHIB: Isobutyl 2-hydroxyisobutyrate, in the above general formula (b-1), R 1 A compound in which i-butyl group is present. nBHIB: n-butyl hydroxyisobutyrate, in the above general formula (b-1), R 1 A compound in which the group is an n-butyl group. <Ingredient (B2)> • PGMEA: Propylene glycol monomethyl ether acetate MMP: Methyl 3-methoxypropionate nBuOAc: n-butyl acetate • EL: Ethyl lactate

[0121] [Resist composition containing liquid crystal resin] Examples 1a-47a, Comparative Examples 1a-6a As the liquid crystal resin, a cresol novolac resin was used, which was a mixture of "EP4080G" and "EP4050G" (both manufactured by Asahi Organic Chemicals Co., Ltd.) in a 1:1 (mass ratio). 84 parts by mass of the above-mentioned cresol novolac resin and 16 parts by mass of a diazonaphthoquinone-type photosensitive agent (product name "DTEP-350", manufactured by Daito Chemix Co., Ltd.) were mixed and dissolved in solvents of the types and proportions shown in Table 1 to prepare resist compositions with the active ingredient concentrations (the above-mentioned cresol novolac resin and photosensitive agent) shown in Tables 1 and 2. Then, using the prepared resist composition, a coating film was formed on a silicon wafer by spin-coating at 1600 rpm. The coating film was then pre-baked at 110°C for 90 seconds to form a resist film. The film thickness was measured at five arbitrarily selected locations on the resist film, and the average of the film thicknesses at these five locations was calculated as the average film thickness. The results are shown in Tables 1 and 2.

[0122] [Table 1]

[0123] [Table 2]

[0124] Table 1 shows that the resist compositions prepared in Examples 1a to 14a can form thicker resist films compared to the resist compositions of Comparative Examples 1a to 6a, which have similar resin concentrations. Furthermore, Table 2 shows that the resist compositions prepared in Examples 15a to 47a can form thick resist films despite having a low liquid crystal resin content of 20 to 25% by mass.

[0125] [Resist composition containing resin for KrF] Examples 1b-35b, Comparative Examples 1b-19b As the resin for KrF, a copolymer having a hydroxystyrene / t-butyl acrylate = 2 / 1 (molar ratio) structure (manufactured by Maruzen Petrochemical Co., Ltd., Mw = 20,000) was used. The above copolymer was mixed with a mixed solvent of the type and proportion shown in Tables 3 and 4 to prepare resist compositions with the active ingredient (KrF resin) concentrations shown in Tables 3 and 4. Then, using the prepared resist composition, a coating film was formed on a silicon wafer by spin-coating at 1600 rpm. This coating film was then pre-baked at 110°C for 90 seconds to form a resist film. The film thickness was measured at five arbitrarily selected locations on the resist film, and the average of these five film thicknesses was calculated as the average film thickness. The results are shown in Tables 3 and 4.

[0126] [Table 3]

[0127] [Table 4]

[0128] Tables 3 and 4 show that the resist compositions prepared in Examples 1b to 35b can form thicker resist films compared to the resist compositions of Comparative Examples 1b to 19b with the same resin concentration.

[0129] [Resist composition containing ArF resin] Synthesis Examples 1-6 (Synthesis of ArF resins (i)-(vi)) (1) Raw material monomer The following raw material monomers were used in the synthesis of ArF resins (i) to (vi). The structures of each raw material monomer are shown in Table 5. EADM: 2-ethyl-2-adamantyl methacrylate MADM: 2-methyl-2-adamantyl methacrylate ·NML:2-Methachlorooxy-4-oxatricyclo[4.2.1.0 3.7 ] Nonan-5-on • GBLM: α-Methachlorooxy-γ-Butyrolactone HADM:3-hydroxy-1-adamantyl methacrylate

[0130] [Table 5]

[0131] (2) Synthesis of ArF resins (i) to (vi) In a 300 mL round-bottom flask, 10 g of raw material monomers were mixed according to the types and molar ratios listed in Table 6. 300 g of tetrahydrofuran (manufactured by Wako Pure Chemical Industries, Ltd., special grade reagent, stabilizer-free) was added, and the mixture was stirred. Degassing was then performed under a nitrogen stream for 30 minutes. After degassing, 0.95 g of 2,2'-azobis(isobutyronitrile) (manufactured by Tokyo Chemical Industry Co., Ltd., reagent) was added, and polymerization was carried out at 60°C under a nitrogen stream to obtain a resin of the desired molecular weight. After the reaction was complete, the reaction solution was cooled to room temperature (25°C) and added dropwise to a large excess of hexane to precipitate the polymer. The precipitated polymer was filtered off, and the resulting solid was washed with methanol. After drying under reduced pressure at 50°C for 24 hours, the target ArF resins (i) to (vi) were obtained. For the obtained ArF resins (i) to (vi), the content ratio of each constituent unit, as well as Mw, Mn, and Mw / Mn, were measured and calculated based on the measurement method described above. These results are shown in Table 6.

[0132] [Table 6]

[0133] Examples 1c-18c, Example 1c-12c One of the ArF resins (i) to (vi) obtained in the above synthesis examples 1 to 6 was mixed with the types of solvents shown in Tables 7 and 8 to prepare resist compositions with the active ingredient (ArF resin) concentrations shown in Tables 7 and 8. Then, using the prepared resist composition, a coating film was formed on a silicon wafer by spin-coating at 3000 rpm. The coating film was then pre-baked at 90°C for 60 seconds to form a resist film. The film thickness was measured at five arbitrarily selected locations on the resist film, and the average of these five film thicknesses was calculated as the average film thickness. The results are shown in Tables 7 and 8.

[0134] [Table 7]

[0135] [Table 8]

[0136] Tables 7 and 8 show that the resist compositions prepared in Examples 1c to 18c can form thicker resist films compared to the resist compositions of Comparative Examples 1c to 12c, which had the same resin concentration.

[0137] [Example 1d, Comparative Example 1d] <Resistance Performance> Table 9 shows the results of the resist performance evaluation performed using the aforementioned resin (ii).

[0138] (Preparation of resist composition) A resist composition was prepared using the formulation shown in Table 9. Of the components of the resist composition in Table 9, the following were used for the acid generator (C) and solvent. Acid generator (C) P-1: Triphenylsulfonium trifluoro-1-butanesulfonate (Sigma-Aldrich) solvent S-1: 2-hydroxyisobutyrate methyl (manufactured by Mitsubishi Gas Chemical Co., Ltd.) S-1: Propylene glycol monomethyl ether acetate (manufactured by Kanto Chemical Co., Ltd.) [Table 9]

[0139] (Method for evaluating the resist performance of a resist composition) A uniform resist composition was rotary coated onto a clean silicon wafer, and then pre-exposure baked (PB) on a 90°C hot plate to form a 50 nm thick resist film. The resulting resist film was irradiated with an electron beam using an electron beam lithography system (ELS-7500, manufactured by Elionix Corporation) with a 1:1 line-and-space setting at 500 nm intervals. After irradiation, the resist film was heated at 90°C for 90 seconds and developed by immersion in an alkaline developer solution of 2.38% by mass of tetramethylammonium hydroxide (TMAH) for 60 seconds. Subsequently, the resist film was washed with ultrapure water for 30 seconds and dried to form a resist pattern. The lines and spaces of the formed resist pattern were observed using a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) to evaluate the reactivity of the resist composition to electron beam irradiation.

[0140] For the evaluation of the resist patterns, both Example 1d and Comparative Example 1d were irradiated with an electron beam using a 1:1 line-and-space setting with 500 nm spacing, resulting in good resist patterns. Furthermore, the film thickness of the resist pattern in Example 1d was thick, confirming that it had sufficient etching resistance for resist pattern transfer. On the other hand, the film thickness of Comparative Example 1d was thin, confirming that it lacked the etching resistance necessary for pattern transfer.

[0141] As described above, when a resist composition that satisfies the requirements of this embodiment is used, a better resist pattern shape can be imparted compared to the resist composition of Comparative Example 1d, which does not satisfy the requirements. Similar effects are observed with resist compositions other than those described in the examples, as long as they satisfy the requirements of this embodiment.

[0142] [Resist composition containing resin and acid generator for ArF resist] Resist compositions were prepared using the formulations shown in Tables 10 and 11, and their solubility was evaluated for the ArF resins (i) to (v) and acid generators (i) to (iv) used as raw materials, as shown in Tables 10 and 11. <Solvent> HBM: Methyl 2-hydroxyisobutyrate (manufactured by Mitsubishi Gas Chemical Company) αMBM: α-Methyl methoxyisobutyrate (synthesized based on "US2014 / 0275016") αFBM: α-Formyloxyisobutyrate methyl (synthesized based on "WO2020 / 004467") αABM: α-acetyloxyisobutyrate methyl (synthesized based on "WO2020 / 004466") 3HBM: Methyl 3-hydroxyisobutyrate (manufactured by Tokyo Chemical Industry Co., Ltd.) PGME: 1-Methoxy-2-propanol (manufactured by Sigma-Aldrich) <Resin> A resin with the following composition (molecular weight) was synthesized using the method described above. (i)EADM / NML = 18 / 82 (Mn = 3750) (ii) MADM / NML = 25 / 75 (Mn = 2740) (iii) MADM / GBLM = 25 / 75 (Mn = 3770) (iv)MADM / NML / HADM=42 / 33 / 25(Mn=7260) (v) Copolymer having a constituent unit of hydroxystyrene / t-butyl acrylate / styrene = 3 / 1 / 1 (molar ratio) (manufactured by Maruzen Petrochemical Co., Ltd., Mw = 12,000) <Acid Generator> (i) WPAG-336 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (ii) WPAG-367 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (iii) WPAG-145 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (iv) Triphenylsulfonium trifluoro-1-butanesulfonate (Sigma-Aldrich)

[0143] Resist compositions for Examples A1-1 to A1-4 and Comparative Example A1-1 were prepared by adding the resins shown in Table 10 to the solvents shown in Table 10 so that the resin concentration was 15 wt%, and adding the acid generators shown in Table 10 so that the acid generator concentration was 1 wt%, respectively. The state after stirring at room temperature for 24 hours was visually evaluated according to the following criteria. Rating S: Dissolved (Clear solution confirmed visually) Evaluation A: Almost completely dissolved (a nearly clear solution was confirmed visually) Evaluation C: Insoluble (Cloudy solution observed visually)

[0144] Resist compositions for Examples A2-1a to A2-5d and Comparative Example A2-1 were prepared by adding the resins shown in Table 11 to the solvents shown in Table 11 so that the resin concentration was 40 wt%, and by adding the types of acid generators shown in Table 11 so that the acid generator concentration was a predetermined level. The state after stirring at room temperature for 1 hour was visually evaluated according to the following criteria. Rating S: 5 wt% dissolution (clear solution confirmed visually) Evaluation A: 1 wt% dissolution (clear solution confirmed visually) Evaluation C: 1 wt% insoluble (cloudy solution observed visually) The results are shown in Tables 10 and 11. [Table 10] [Table 11-1] [Table 11-2]

[0145] Table 10 shows that the resist compositions prepared in Examples A1-1 to A1-5 exhibit superior solubility in resins compared to the resist composition of Comparative Example A1-1, and that various resist compositions can be prepared. In particular, resist compositions in which solvent (B) contains αFBM as solvent (B2) show high solubility in any resin and are suitably used.

[0146] Table 11 shows that the resist compositions prepared in Examples A2-1a to A2-5d exhibit superior solubility with acid generators compared to the resist composition of Comparative Example A2-1, indicating that resist compositions can be prepared using any of the acid generators. In particular, resist compositions in which solvent (B) contains αMBM, αFBM, or 3HBM as solvent (B2) show high solubility with any of the acid generators and are suitable for use.

[0147] [Resist composition containing resin for KrF] As a resin for KrF, a copolymer having a constituent unit of hydroxystyrene / t-butyl acrylate / styrene = 3 / 1 / 1 (molar ratio) (manufactured by Maruzen Petrochemical Co., Ltd., Mw = 12,000) was mixed with the types of solvents shown in Table 12 to prepare resist compositions with the concentrations of the active ingredients (resins for KrF) listed in Table 12. Then, using the prepared resist composition, a coating film was formed on a silicon wafer by spin-coating at 1500 rpm. The coating film was then pre-baked at 140°C for 60 seconds to form a resist film. The film thickness was measured at five arbitrarily selected locations on the resist film, and the average of these five film thicknesses was calculated as the average film thickness to evaluate the film thickness. Film uniformity was also evaluated by dividing the difference between the maximum and minimum film thicknesses by the average value. The results are shown in Table 12. Film thickness: Rating A: 20 μm or larger Evaluation B: 15 μm or larger and less than 20 μm Rating C: Less than 15 μm Film uniformity: Rating A: Less than 15 Rating B: 15 or higher, less than 30 Rating C: 30 or higher

[0148] [Table 12]

[0149] Table 12 shows that the resist compositions prepared in Examples A3-1a to A3-5c can form thicker resist films compared to the resist compositions of Comparative Examples A3-1a to A3-1b. In particular, resist compositions in which solvent (B) contains αMBM, αFBM, 3HBM, or PGME as solvent (B2) are all suitable for use due to their excellent film uniformity. Furthermore, resist compositions containing αFBM can be suitable for use because they can achieve a film thickness of 20 μm or more when the resin concentration is 40 wt%. Moreover, resist compositions containing αMBM can be suitable for use because they can achieve a film thickness of 20 μm or more when the resin concentration is 45 wt%.

[0150] <Evaluation of in-plane uniformity of resist film> The aforementioned KrF resin (a copolymer having constituent units of hydroxystyrene / t-butyl acrylate / styrene = 3 / 1 / 1 (molar ratio) (manufactured by Maruzen Petrochemical Co., Ltd., Mw = 12,000)) was mixed with the types of solvents shown in Table 13 to prepare resist compositions with the concentrations of the active ingredients (KrF resin) listed in Table 13. Then, using the prepared resist composition, a coating film was formed on a silicon wafer at a main spin of 1200 rpm. The coating film was pre-baked at 110°C for 90 seconds to form a resist film with an average thickness of 7.2 μm. The film thickness was measured at 50 points on the resist film at 3 mm intervals in the diametrical direction. The in-plane uniformity was evaluated by calculating the film thickness unevenness 3σ by dividing three times the standard deviation of the film thickness by the average film thickness. The results are shown in Table 13. In-plane uniformity: Rating A: 3σ ≤ 0.02 Rating B: 0.02 or higher and less than 0.04 Rating C: 0.04 or higher [Table 13]

[0151] <Resistance Performance> Table 14 shows the results of the resist performance evaluation performed using the aforementioned resin (ii) (MADM / NML=25 / 75). Pattern evaluation: Evaluation S: A rectangular resist pattern is being formed. Evaluation A: A generally rectangular resist pattern is being formed. Evaluation C: A rectangular resist pattern is not being formed. Pattern film thickness: Evaluation A: It has the etching resistance necessary for pattern transfer. Evaluation C: It does not have the etching resistance necessary for pattern transfer.

[0152] (Preparation of resist composition) A resist composition was prepared with the formulation shown in Table 14. Among the components of the resist composition in Table 14, the following were used for the acid generator (C) and the solvent. Acid generator (C) P-1: Triphenylsulfonium trifluoro-1-butanesulfonate (Sigma-Aldrich) [Table 14]

[0153] (Evaluation method for resist performance of resist composition) After spin-coating a uniform resist composition onto a clean silicon wafer, it was pre-baked (PB) on a hot plate at 90 °C to form a resist film with a thickness of 50 nm. For the obtained resist film, an electron beam with a 1:1 line-and-space setting at an interval of 500 nm was irradiated using an electron beam lithography apparatus (ELS-7500, manufactured by Elionix, Inc.). After the irradiation, the resist film was heated at 90 °C for 90 seconds and developed by immersing it in an alkaline developer of 2.38 mass% tetramethylammonium hydroxide (TMAH) for 60 seconds. Then, the resist film was washed with ultrapure water for 30 seconds and dried to form a resist pattern. Regarding the formed resist pattern, the line and space were observed with a scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) to evaluate the reactivity of the resist composition by electron beam irradiation.

[0154] Regarding the evaluation of the resist patterns, good resist patterns were obtained in both Examples A5-1 to A5-6b and Comparative Example A5 by irradiating them with an electron beam using a 1:1 line-and-space setting with 500 nm spacing. Furthermore, regarding the film thickness of the resist patterns, it was confirmed that the film thickness of Examples A5-1 to A5-6b was thick and possessed sufficient etching resistance for transferring the resist patterns. On the other hand, it was confirmed that the film thickness of Comparative Example A5 was thin and lacked the etching resistance necessary for pattern transfer. In particular, a resist composition in which solvent (B) contains 3HBM as solvent (B2) is suitable for use because the shape of the obtained resist pattern is rectangular and it has excellent pattern transfer performance.

[0155] As described above, when a resist composition that satisfies the requirements of this embodiment is used, a better resist pattern shape can be imparted compared to the resist composition of Comparative Example A5, which does not satisfy the requirements.

[0156] As long as the requirements of this embodiment described above are met, other resist compositions besides those described in the examples will also exhibit similar effects.

Claims

1. A resist composition comprising a resin (A) and a solvent (B) containing a compound (B1) represented by the following general formula (b-1), The solvent (B) includes one or more solvents (B2) other than the compound (B1) selected from the group consisting of methyl α-methoxyisobutyrate, methyl α-formyloxyisobutyrate, methyl α-acetyloxyisobutyrate, and methyl 3-hydroxyisobutyrate. If the solvent (B2) includes one or more selected from the group consisting of methyl α-methoxyisobutyrate and methyl 3-hydroxyisobutyrate, then the solvent (B2) contains 0.0001% by mass or more and 100% by mass or less based on the total amount (100% by mass) of the compound (B1). A resist composition wherein the content of the active ingredient on a total basis of the resist composition is 45% by mass or less. 【Chemistry 1】 [In the above formula (b-1), R １ This is an alkyl group having 1 to 10 carbon atoms.

2. The resist composition according to claim 1, further comprising at least one additive (C) selected from photosensitive agents and acid generators.

3. In the above general formula (b-1), R １ The resist composition according to claim 1, wherein the group is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, or a t-butyl group.

4. In the above general formula (b-1), R １ The resist composition according to claim 1, wherein the group is an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, an s-butyl group, or a t-butyl group.

5. The resist composition according to claim 1, wherein the resin (A) comprises a novolac-type resin (A1).

6. The resist composition according to claim 1, wherein the resin (A) comprises a resin (A2) having at least one of a constituent unit (a2-1) derived from a phenolic hydroxyl group-containing compound and a constituent unit (a2-2) that can decompose by the action of an acid, base or heat to form an acidic functional group.

7. The resist composition according to claim 1, wherein the resin (A) comprises a resin (A3) having a structural unit (a3-1) having an adamantane structure.

8. The resist composition according to claim 7, wherein the resin (A3) is a copolymer having a structural unit (a3-2) having a lactone structure together with a structural unit (a3-1).

9. The resist composition according to claim 7, wherein the content of a constituent unit (a3-1α) having an adamantane structure substituted with a hydroxyl group is less than 50 mol% of the total amount of constituent units of the resin (A3).

10. The resist composition according to claim 1, wherein the resin (A) comprises a resin (A4) having two or more constituent units, which are any two of the following: a constituent unit (a2-1) derived from a phenolic hydroxyl group-containing compound, a constituent unit (a2-2) that can decompose by the action of an acid, a base or heat to form an acidic functional group, a constituent unit (a3-1) having an adamantane structure, and a constituent unit (a3-2) having a lactone structure.

11. Step (1): A step of applying the resist composition according to any one of claims 1 to 10 onto a substrate to form a coating film. Step (2): A step of performing a heat treatment after step (1), and A method for forming a resist film, comprising the step (3): forming a resist pattern.

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