JP7468744B1 - Radiation-sensitive composition, cured film and method for producing same, semiconductor device, and display device - Google Patents

Abstract

[Problem] To provide a radiation-sensitive composition capable of forming a cured film having excellent radiation sensitivity, low dielectric constant, and excellent transparency. [Solution] A radiation-sensitive composition comprising: [A] a polymer component containing a first structural unit having a partial structure represented by formula (1) and a second structural unit having a partial structure represented by formula (2) in the same molecule or in different molecules; and [B] a photoacid generator, the radiation-sensitive composition containing 5 to 50 mass% of the first structural unit and 0.1 to 20 mass% of the second structural unit relative to all structural units of the polymer component. In formula (1), Ar1 is a divalent aromatic ring group. Y1 is an acid-dissociable group. In formula (2), R1, R2, and R3 are each independently a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a phenyl group. However, at least one of R1, R2, and R3 is an alkoxy group having 1 to 6 carbon atoms. "*" represents a bond bonded to a carbon atom. TIFF0007468744000027.tif31170 [Selected image] None

Description

The present invention relates to a radiation-sensitive composition, a cured film and a method for producing the same, a semiconductor device, and a display device.

Cured films (e.g., interlayer insulating films, spacers, protective films, etc.) of semiconductor elements and display elements are generally formed using a radiation-sensitive composition that contains a polymer component and a radiation-sensitive compound (a photoacid generator, a photopolymerization initiator, etc.). For example, a coating film formed from the radiation-sensitive composition is irradiated with radiation, then developed to form a pattern, and then heated for thermal curing to obtain a cured film having a pattern shape.

Various radiation-sensitive compositions have been proposed as materials for forming cured films to be provided on semiconductor elements and display elements (see, for example, Patent Documents 1 to 3). Patent Document 1 discloses a radiation-sensitive resin composition used for forming a cured film, which contains a polymer containing a structural unit having a partial structure in which a trialkoxysilyl group is bonded to an alkyl chain, a benzene ring, or a naphthalene ring, an epoxy compound, and a radiation-sensitive compound. Patent Document 1 also describes that the radiation-sensitive composition of Patent Document 1 can provide a cured film having excellent heat resistance, chemical resistance, surface hardness, development adhesion, transparency, and low dielectric properties, and also has satisfactory properties such as storage stability and sensitivity.

Patent Document 2 discloses a radiation-sensitive composition that contains a polymer component having a structural unit derived from maleimide and a structural unit containing an alkoxysilyl group in the same or different polymers, and a radiation-sensitive compound. Patent Document 2 describes that the radiation-sensitive composition of Patent Document 2 has high radiation sensitivity, and that by using the composition, a cured film that has high chemical resistance and low corrosion resistance to metal wiring can be obtained.

Patent Document 3 discloses a radiation-sensitive composition that contains a polymer component that contains, in the same or different polymers, a structural unit having a partial structure in which a trialkylsilyloxy group is bonded to an aromatic ring and a structural unit having a crosslinkable group, and a radiation-sensitive acid generator. Patent Document 3 also describes that the radiation-sensitive composition of Patent Document 3 has good radiation sensitivity, storage stability, outgassing properties, and coatability due to the inclusion of the above structural unit in the polymer component.

JP 2017-107024 A JP 2019-174614 A JP 2021-196577 A

The radiation-sensitive composition of Patent Document 3 makes it possible to obtain a cured film with reduced outgassing while maintaining good radiation sensitivity. However, the cured film obtained from the radiation-sensitive composition of Patent Document 3 has a relatively high dielectric constant, leaving room for further improvement. In addition, in applications requiring transparency, the film obtained from the radiation-sensitive composition is required to have high transmittance.

The present invention has been made in consideration of the above problems, and has as its main object to provide a radiation-sensitive composition capable of forming a cured film having excellent radiation sensitivity, a low dielectric constant, and excellent transparency.

The present invention provides the following radiation-sensitive composition, cured film and method for producing the same, semiconductor device, and display device.

（式（１）中、Ａｒ^１は２価の芳香環基である。Ｙ^１は酸解離性基である。ｎは０又は１である。「＊」は結合手を表す。ただし、ｎが０の場合、前記第１構造単位はマレイミド環を有する単量体に由来する構造単位であり、Ｙ^１は前記マレイミド環の窒素原子に結合している。）

（式（２）中、Ｒ^１、Ｒ^２及びＲ^３は、互いに独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルコキシ基、炭素数１～１０のアルキル基、又はフェニル基である。ただし、Ｒ^１、Ｒ^２及びＲ^３のうち１つ以上は、炭素数１～６のアルコキシ基である。「＊」は、炭素原子に結合する結合手を表す。） [1] A radiation-sensitive composition comprising: [A] a polymer component including, in the same molecule or in different molecules, a first structural unit having a partial structure represented by the following formula (1) and a second structural unit having a partial structure represented by the following formula (2), and [B] a photoacid generator, wherein the first structural unit is contained in an amount of 5 to 50 mass % and the second structural unit is contained in an amount of 0.1 to 20 mass % based on the total structural units of the polymer component:

(In formula (1), ^Ar1 is a divalent aromatic ring group. ^Y1 is an acid dissociable group. n is 0 or 1. "*" represents a bond. However, when n is 0, the first structural unit is a structural unit derived from a monomer having a maleimide ring, and ^Y1 is bonded to a nitrogen atom of the maleimide ring.)

(In formula (2), R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a phenyl group. However, at least one of R ¹ , R ² and R ³ is an alkoxy group having 1 to 6 carbon atoms. "*" represents a bond bonded to a carbon atom.)

[2] A cured film formed using the radiation-sensitive composition described in [1] above.
[3] A method for producing a cured film, comprising: forming a coating film using the radiation-sensitive composition according to the above [1]; exposing at least a part of the coating film to light; developing the exposed coating film; and heating the developed coating film.
[4] A semiconductor element comprising the cured film according to [2] above.
[5] A display element comprising the cured film according to [2] above.

The radiation-sensitive composition of the present invention has excellent radiation sensitivity. In addition, the radiation-sensitive composition of the present invention can form a cured film that has a low dielectric constant and excellent transparency.

Below, matters related to the embodiments will be explained in detail. In this specification, a numerical range described using "~" means that the numerical range includes the numerical range before and after "~" as the lower and upper limits. A "structural unit" refers to a unit that mainly constitutes the main chain structure, and is a unit that is contained in at least two units in the main chain structure.

In this specification, the term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "linear hydrocarbon group" means a linear hydrocarbon group and a branched hydrocarbon group that do not include a cyclic structure in the main chain and are composed only of a linear structure. However, the linear hydrocarbon group may be saturated or unsaturated. The term "alicyclic hydrocarbon group" means a hydrocarbon group that includes only an alicyclic hydrocarbon structure as a ring structure and does not include an aromatic ring structure. However, the alicyclic hydrocarbon group does not have to be composed only of an alicyclic hydrocarbon structure, and also includes those that have a linear structure as a part of it. The term "aromatic hydrocarbon group" means a hydrocarbon group that includes an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not have to be composed only of an aromatic ring structure, and may include a linear structure or an alicyclic hydrocarbon structure as a part of it. The ring structure of the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent consisting of a hydrocarbon structure. The term "cyclic hydrocarbon group" means a hydrocarbon group that includes an alicyclic hydrocarbon group and an aromatic hydrocarbon group. "Aromatic ring group" refers to a group in which r hydrogen atoms (r is an integer) have been removed from the ring portion of an aromatic ring. "Aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles. "(Meth)acrylic" includes "acrylic" and "methacrylic".

<Radiation-sensitive composition>
The radiation-sensitive composition of the present disclosure (hereinafter also referred to as "the composition") contains a polymer component [A] and a photoacid generator [B]. Each component contained in the composition and other components that are blended as necessary will be described below. Note that, unless otherwise specified, each component may be used alone or in combination of two or more types.

（式（１）中、Ａｒ^１は２価の芳香環基である。Ｙ^１は酸解離性基である。ｎは０又は１である。「＊」は結合手を表す。ただし、ｎが０の場合、前記第１構造単位はマレイミド環を有する単量体に由来する構造単位であり、Ｙ^１は前記マレイミド環の窒素原子に結合している。）

（式（２）中、Ｒ^１、Ｒ^２及びＲ^３は、互いに独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルコキシ基、炭素数１～１０のアルキル基、又はフェニル基である。ただし、Ｒ^１、Ｒ^２及びＲ^３のうち１つ以上は、炭素数１～６のアルコキシ基である。「＊」は、炭素原子に結合する結合手を表す。） <Polymer component (A)>
The polymer component [A] contains a first structural unit having a partial structure represented by the following formula (1) and a second structural unit having a partial structure represented by the following formula (2) in the same molecule or in different molecules. The polymer component [A] contains 5 to 50% by mass of the first structural unit and 0.1 to 20% by mass of the second structural unit, based on the total structural units of the polymer component [A].

(In formula (1), ^Ar1 is a divalent aromatic ring group. ^Y1 is an acid dissociable group. n is 0 or 1. "*" represents a bond. However, when n is 0, the first structural unit is a structural unit derived from a monomer having a maleimide ring, and ^Y1 is bonded to a nitrogen atom of the maleimide ring.)

(In formula (2), R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a phenyl group. However, at least one of R ¹ , R ² and R ³ is an alkoxy group having 1 to 6 carbon atoms. "*" represents a bond bonded to a carbon atom.)

(First structural unit)
The first structural unit has a partial structure represented by the above formula (1). When the composition is irradiated with radiation, the acid dissociable group (Y ¹ ) in the above formula (1) is eliminated by the action of the acid generated from the photoacid generator [B]. As a result, when n in the above formula (1) is 1, a hydroxyl group bonded to the aromatic ring is generated, and when n is 0, -NH- is generated. As a result, the solubility (more specifically, alkali solubility) of the polymer component [A] in the developer can be changed, and a cured film on which a pattern is formed can be obtained. In addition, the generation of a hydroxyl group or -NH- bonded to the aromatic ring can increase the curing reactivity of the polymer component [A]. In order to increase the curing reactivity of the polymer component [A], it is preferable that n in the above formula (1) is 1. In this specification, "alkali soluble" means that the compound can be dissolved or swelled in an alkaline aqueous solution such as a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH).

In the above formula (1), the divalent aromatic ring group represented by Ar ¹ is a group obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. Examples of the aromatic ring include a benzene ring, a naphthalene ring, and an anthracene ring. When the aromatic ring of Ar ¹ has a substituent, examples of the substituent include a halogen atom, an alkyl group, and an alkoxy group. Of these, Ar ¹ is preferably a substituted or unsubstituted phenylene group, naphthylene group, or anthrylene group, and more preferably a substituted or unsubstituted phenylene group or naphthylene group.

（式（Ｙ－１）中、Ｒ^４、Ｒ^５及びＲ^６は、互いに独立して、水素原子、ハロゲン原子、ヒドロキシ基、炭素数１～２０の１価の炭化水素基、又は当該炭化水素基が有する水素原子の一部若しくは全部が置換基で置換された基である。「＊」は結合手を表す。）

（式（Ｙ－２）中、Ｒ^７、Ｒ^８及びＲ^９は、次の（１）又は（２）を満たす。（１）Ｒ^７は水素原子、炭素数１～１２のアルキル基又は炭素数３～２０の１価の脂環式炭化水素基である。Ｒ^８及びＲ^９は、互いに独立して、炭素数１～１２のアルキル基、炭素数３～２０の１価の脂環式炭化水素基、又は炭素数７～２０のアラルキル基である。（２）Ｒ^７は、水素原子、炭素数１～１２のアルキル基又は炭素数３～２０の１価の脂環式炭化水素基である。Ｒ^８及びＲ^９は、互いに合わせられＲ^８及びＯＲ^９が結合する炭素原子とともに構成される環状エーテル構造を表す。「＊」は結合手を表す。）

（式（Ｙ－３）中、Ｒ^１０は３級アルキル基である。「＊」は結合手を表す。） The acid dissociable group represented by ^Y1 is not particularly limited. In this specification, the term "acid dissociable group" refers to a group that substitutes a polar hydrogen atom of an acid group (e.g., a hydroxyl group, a carboxyl group, an amino group, a sulfo group, etc.) and dissociates by the action of an acid. From the viewpoint of enhancing the effect of improving the sensitivity, storage stability, and pattern shape properties of the present composition, the acid dissociable group represented by ^Y1 is preferably a group represented by the following formula (Y-1), formula (Y-2), or formula (Y-3).

(In formula (Y-1), R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a group in which some or all of the hydrogen atoms of the hydrocarbon group have been substituted with a substituent. "*" represents a bond.)

(In formula (Y-2), R ⁷ , R ⁸ and R ⁹ satisfy the following (1) or (2). (1) R ⁷ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ⁸ and R ⁹ are each independently an alkyl group having 1 to 12 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. (2) R ⁷ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ⁸ and R ⁹ are combined together to represent a cyclic ether structure formed together with the carbon atoms to which R ⁸ and OR ⁹ are bonded. "*" represents a bond.)

(In formula (Y-3), R ¹⁰ is a tertiary alkyl group. "*" represents a bond.)

In the above formula (Y-1), examples of the monovalent hydrocarbon group represented by R ⁴ , R ⁵ or R ⁶ include monovalent chain hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 4 to 20 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms. Specific examples of these chain hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl, and n-pentyl; and alkenyl groups such as vinyl and allyl.

Examples of the alicyclic hydrocarbon group having 4 to 20 carbon atoms include monocyclic alicyclic hydrocarbon groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and a cyclooctyl group; and polycyclic alicyclic hydrocarbon groups such as a bicyclo[2.2.2]octyl group, a tricyclo[5.2.1.0 ^2,6 ]decyl group, an adamantyl group, and a norbornyl group.

Examples of the aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; and aralkyl groups such as a benzyl group and a phenethyl group.
When the group represented by R ⁴ , R ⁵ or R ⁶ is a group in which a part or all of the hydrogen atoms of a hydrocarbon group having 1 to 20 carbon atoms have been substituted with a substituent, examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) and a hydroxy group.

From the viewpoint of improving the radiation sensitivity and coatability of the composition, and of obtaining a cured film with little outgassing, the group represented by R ⁴ , R ⁵ or R ⁶ is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms, among the above groups.

In the above formula (Y-2), the alkyl group having 1 to 12 carbon atoms represented by R ⁷ , R ⁸ and R ⁹ may be linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 6, and more preferably 1 to 4. Specific examples of the alkyl group having 1 to 12 carbon atoms represented by R ⁷ , R ⁸ and R ⁹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and the like.

Examples of the monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms represented by R ⁷ , R ⁸ and R ⁹ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an isobornyl group, an adamantyl group, etc. Examples of the aralkyl groups having 7 to 20 carbon atoms represented by R ⁸ and R ⁹ include a benzyl group, a phenethyl group, a methylbenzyl group, etc.

The cyclic ether structure formed by combining ^R8 and ^R9 with each other preferably has 5 or more ring members. Specific examples thereof include a tetrahydrofuran ring structure and a tetrahydropyran ring structure.

Among these, R ⁷ is preferably a hydrogen atom, a methyl group or an ethyl group, and more preferably a hydrogen atom, since they are easily dissociated by an acid.
In the above formula (Y-3), the tertiary alkyl group represented by R ¹⁰ is preferably a tert-butyl group in that it has good leaving ability.

（式（Ｙ１－１）及び式（Ｙ１－２）中、Ａ^１及びＡ^２は、互いに独立して、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基、又は炭素数１～６のアルコキシ基である。ｎ１は０～４の整数である。ｎ２は０～６の整数である。ただし、ｎ１が２以上の場合、複数のＡ^１は、互いに同一の基又は異なる基である。ｎ２が２以上の場合、複数のＡ^２は、互いに同一の基又は異なる基である。Ｒ^４、Ｒ^５及びＲ^６は、上記式（Ｙ－１）と同義である。「＊」は、結合手を表す。） When Y ¹ in the above formula (1) is a group represented by the above formula (Y-1), the group represented by the above formula (1) is preferably represented by the following formula (Y1-1) or formula (Y1-2).

(In formula (Y1-1) and formula (Y1-2), A ¹ and A ² are each independently a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n1 is an integer from 0 to 4. n2 is an integer from 0 to 6. However, when n1 is 2 or more, a plurality of A ¹ 's are the same or different groups. When n2 is 2 or more, a plurality of A ² 's are the same or different groups. R ⁴ , R ⁵ and R ⁶ are the same as in formula (Y-1) above. "*" represents a bond.)

In the above formula (Y1-1) or formula (Y1-2), specific examples of the alkyl group having 1 to 6 carbon atoms and the alkoxy group having 1 to 6 carbon atoms represented by ^A1 or ^A2 include the groups exemplified as the alkyl group and alkoxy group for ^R4 to ^R6 in the above formula (Y-1).

The position of the group "-O-SiR ⁴ R ⁵ R ⁶ " bonded to the aromatic ring may be any position relative to other groups except A ¹ and A ^2. For example, in the case of the above formula (Y1-1), the position of "-O-SiR ⁴ R ⁵ R ⁶ " may be any of the ortho, meta, and para positions, and is preferably the para position. n1 is preferably 0 or 1, and more preferably 0. n2 is preferably 0 to 2, and more preferably 0. When the first structural unit has a group represented by the above formula (Y-1), it is particularly preferable that the first structural unit is a structural unit having a group represented by the above formula (Y1-1) among these.

（式（１－１Ａ）及び式（１－２Ａ）中、Ｒ^Ａは、水素原子、メチル基、ヒドロキシメチル基、シアノ基又はトリフルオロメチル基である。Ｒ^４、Ｒ^５及びＲ^６は、上記式（Ｙ－１）と同義である。Ａ^１、Ａ^２、ｎ１及びｎ２は、上記式（Ｙ１－１）及び式（Ｙ１－２）と同義である。） When Y ¹ in the above formula (1) is a group represented by the above formula (Y-1), the first structural unit is preferably a structural unit derived from a monomer having a polymerizable carbon-carbon unsaturated bond (hereinafter also referred to as an "unsaturated monomer"). Specifically, the first structural unit is preferably at least one selected from the group consisting of structural units represented by the following formula (1-1A) and structural units represented by the following formula (1-2A), and is more preferably a structural unit represented by the following formula (1-1A).

(In formulae (1-1A) and (1-2A), R ^A is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. R ⁴ , R ⁵ , and R ⁶ are the same as defined in formula (Y-1) above. A ¹ , A ² , n1, and n2 are the same as defined in formulae (Y1-1) and (Y1-2) above.)

When Y ¹ in the above formula (1) is a group represented by the above formula (Y-1), specific examples of the monomer that provides the first structural unit include, when n in the above formula (1) is 1, 4-isopropenylphenyloxytrimethylsilane, 4-isopropenylphenyloxytriethylsilane, 4-isopropenylphenyloxymethyldiethylsilane, 4-isopropenylphenyloxydimethylethylsilane, 3-isopropenylphenyloxytrimethylsilane, 4-isopropenylnaphthyloxytrimethylsilane, 4-vinylphenyloxytrimethylsilane, 4-vinylphenyloxytriethylsilane, 4-vinylphenyloxymethyldiethylsilane, 4-vinylphenyloxydimethylethylsilane, 3-vinylphenyloxytrimethylsilane, 4-vinylnaphthyloxytrimethylsilane, 4-trimethylsilyloxy-N-phenylmaleimide, 4-trimethylsilyloxyphenyl(meth)acrylate, and the like.
Examples of the compound in which n is 0 in the above formula (1) include N-trimethylsilylmaleimide, N-triethylsilylmaleimide, and N-methyldiethylsilylmaleimide.

（式（１－１Ｂ）及び式（１－２Ｂ）中、Ｒ^Ｂは、水素原子、メチル基、ヒドロキシメチル基、シアノ基又はトリフルオロメチル基である。Ｒ^７、Ｒ^８及びＲ^９は、上記式（Ｙ－２）と同義である。Ｒ^１０は、上記式（Ｙ－３）と同義である。Ａ^３は、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基、又は炭素数１～６のアルコキシ基である。ｎ３は０～４の整数である。） When Y ¹ in the above formula (1) is a group represented by the above formula (Y-2) or formula (Y-3), the first structural unit is preferably a structural unit derived from an unsaturated monomer. Specifically, the first structural unit is preferably at least one selected from the group consisting of a structural unit represented by the following formula (1-1B) and a structural unit represented by the following formula (1-2B).

(In formulas (1-1B) and (1-2B), R ^{1 B} is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. R ⁷ , R ⁸ , and R ⁹ are the same as in formula (Y-2) above. ^{R 10} is the same as in formula (Y-3) above. A ³ is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n3 is an integer from 0 to 4.)

（式（１－２－１）～式（１－２－３）及び式（１－３－１）中、Ｒ^Ｂは、水素原子、メチル基、ヒドロキシメチル基、シアノ基又はトリフルオロメチル基である。） When Y ¹ in the above formula (1) is a group represented by the above formula (Y-2), specific examples of the monomer that provides the first structural unit include the structural units represented by the following formulas (1-2-1) to (1-2-3). When Y ¹ in the above formula (1) is a group represented by the above formula (Y-3), specific examples of the monomer that provides the first structural unit include the structural unit represented by the following formula (1-3-1).

(In formulas (1-2-1) to (1-2-3) and (1-3-1), R ^B represents a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group or a trifluoromethyl group.)

From the viewpoint of radiation sensitivity and transmittance, it is preferable that, among the above, the first structural unit is a group represented by formula (Y-1) in which Y ¹ in formula (1) is a group represented by formula (Y-1).

The content of the first structural unit in the polymer component [A] is 5 to 50% by mass relative to the total structural units constituting the polymer component [A]. If the content of the first structural unit is less than 5% by mass, the radiation sensitivity of the composition is low and the resolution is poor. If the content of the first structural unit is more than 50% by mass, the transmittance of the film obtained using the composition is low and outgassing is likely to occur from the cured film. From the above viewpoints, the content of the first structural unit in the polymer component [A] is preferably 10% by mass or more, more preferably 15% by mass or more. From the viewpoint of achieving both the transmittance and resolution of the film, the content of the first structural unit is preferably 45% by mass or less, more preferably 40% by mass or less, relative to the total structural units constituting the polymer component [A].

(Second structural unit)
The second structural unit is a structural unit having a partial structure represented by the above formula (2). The second structural unit differs from the first structural unit in that the second structural unit does not have the partial structure represented by the above formula (1).

In the above formula (2), examples of the alkoxy group having 1 to 6 carbon atoms represented by R ¹ , R ² or R ³ include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group. Of these, the alkoxy group represented by R ¹ , R ² or R ³ preferably has 1 to 5 carbon atoms, more preferably has 1 to 3 carbon atoms, and is even more preferably a methoxy group or an ethoxy group. In particular, when the group represented by the above formula (2) is bonded to an aromatic ring group, it is preferable that at least one of R ¹ , R ² and R ³ is a methoxy group. When the group represented by the above formula (2) is bonded to a chain hydrocarbon group, it is preferable that at least one of R ¹ , R ² and R ³ is an ethoxy group.

The alkyl group having 1 to 10 carbon atoms represented by R ¹ , R ² or R ³ may be linear or branched. Examples of the alkyl group represented by R ¹ , R ² or R ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, etc. Of these, the alkyl group represented by R ¹ , R ² or R ³ is preferably a methyl group, an ethyl group or a propyl group.

At least one of the groups represented by R ¹ , R ² or R ³ is an alkoxy group having 1 to 6 carbon atoms. When R ¹ , R ² or R ³ is a group other than an alkoxy group having 1 to 6 carbon atoms, examples of the group include a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 10 carbon atoms, and a phenyl group.

From the viewpoint of obtaining a cured film having excellent heat resistance by forming a crosslinked structure, it is preferable that two or more of R ¹ , R ² and R ³ are alkoxy groups having 1 to 6 carbon atoms, and it is more preferable that all of R ¹ , R ² and R ³ are alkoxy groups having 1 to 6 carbon atoms.

In the second structural unit, the group represented by the formula (2) may be bonded to a carbon atom. From the viewpoint of improving the transparency and outgassing properties of the film, it is preferable that the group represented by the formula (2) is bonded to an aromatic ring group or a chain hydrocarbon group, or to a carbon atom constituting the main chain of the polymer. When the group represented by the formula (2) is bonded to an aromatic ring group, examples of the aromatic ring to which the group represented by the formula (2) is bonded include a benzene ring, a naphthalene ring, and an anthracene ring. These rings may have a substituent such as an alkyl group. When the group represented by the formula (2) is bonded to a chain hydrocarbon group, examples of the chain hydrocarbon group include an alkanediyl group and an alkenediyl group.

（式（２－１）、式（２－２）及び式（２－３）中、Ａ^４及びＡ^５は、互いに独立して、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基又は炭素数１～６のアルコキシ基である。ｍ１は０～４の整数である。ｍ２は０～６の整数である。ただし、ｍ１が２以上の場合、複数のＡ^４は同一又は異なる。ｍ２が２以上の場合、複数のＡ^５は同一又は異なる。Ｒ^１１はアルカンジイル基である。Ｒ^１、Ｒ^２及びＲ^３は、上記式（２）と同義である。「＊」は、結合手を表す。） When the group represented by the formula (2) is bonded to an aromatic ring group or a chain hydrocarbon group, the group represented by the formula (2) is preferably bonded to a benzene ring, a naphthalene ring, or an alkyl chain among the above. Specifically, when the group represented by the formula (2) is bonded to an aromatic ring group or a chain hydrocarbon group, the second structural unit preferably has at least one selected from the group consisting of a group represented by the following formula (2-1), a group represented by the following formula (2-2), and a group represented by the following formula (2-3).

(In formula (2-1), formula (2-2) and formula (2-3), ^A4 and ^A5 are each independently a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. m1 is an integer from 0 to 4. m2 is an integer from 0 to 6. However, when m1 is 2 or more, multiple ^A4s are the same or different. When m2 is 2 or more, multiple ^A5s are the same or different. ^R11 is an alkanediyl group. ^R1 , ^R2 and ^R3 are the same as in formula (2) above. "*" represents a bond.)

In the above formula (2-1) or formula (2-2), examples of the alkoxy group having 1 to 6 carbon atoms and the alkyl group having 1 to 6 carbon atoms represented by A ⁴ or A ⁵ include the same groups as those exemplified as R ¹ to R ³ in the above formula (2). The bonding position of the group "-SiR ¹ R ² R ³ " to the aromatic ring may be any position relative to the bonding positions of other groups other than A ⁴ and A ⁵ (i.e., the position of the bond represented by "*"). For example, in the case of the above formula (2-1), the position of "-SiR ¹ R ² R ³ " may be any of the ortho position, meta position, and para position relative to the position of the bond represented by "*". The para position is preferable. m1 is preferably 0 or 1, and more preferably 0. m2 is preferably 0 to 2, and more preferably 0.
In the above formula (2-3), R ¹¹ is preferably linear. From the viewpoint of increasing the heat resistance of the resulting cured film, R ¹¹ preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.

In terms of increasing the heat resistance, chemical resistance and hardness of the cured film, the second structural unit preferably has at least one selected from the group consisting of the group represented by the above formula (2-1) and the group represented by the above formula (2-2) among the above formulas (2-1) to (2-3). In addition, when the group "-SiR ¹ R ² R ³ " is directly bonded to the aromatic ring, it is possible to stabilize the silanol group generated in the presence of water. This is preferable in that the solubility of the exposed portion in an alkaline developer can be increased and a good pattern can be formed. Among these, it is particularly preferable that the second structural unit is a structural unit having a group represented by the above formula (2-1).

（式（２Ａ－１）及び式（２Ａ－２）中、Ｒ^Ｃは、水素原子、メチル基、ヒドロキシメチル基、シアノ基又はトリフルオロメチル基である。Ｒ^１２は、２価の芳香環基又は鎖状炭化水素基である。Ｒ^１３は、単結合、２価の芳香環基又は鎖状炭化水素基である。Ｒ^１、Ｒ^２及びＲ^３は、上記式（１）と同義である。） The second structural unit is preferably a structural unit derived from a monomer having a polymerizable carbon-carbon unsaturated bond as a bond involved in polymerization (hereinafter also referred to as an "unsaturated monomer"). Specifically, the second structural unit is preferably at least one selected from the group consisting of structural units represented by the following formula (2A-1) and structural units represented by the following formula (2A-2).

(In formula (2A-1) and formula (2A-2), R ^C is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. R ¹² is a divalent aromatic ring group or a chain hydrocarbon group. R ¹³ is a single bond, a divalent aromatic ring group, or a chain hydrocarbon group. R ¹ , R ² , and R ³ are each defined as in formula (1).)

In the above formula (2A-1) and formula (2A-2), the divalent aromatic ring group represented by R ¹² or R ¹³ is preferably a substituted or unsubstituted phenylene group, or a substituted or unsubstituted naphthalenediyl group. In the aromatic ring group, examples of the substituent bonded to the ring include one or more selected from the group consisting of a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. The divalent chain hydrocarbon group is preferably an alkanediyl group having 1 to 6 carbon atoms, and more preferably an alkanediyl group having 1 to 4 carbon atoms.

Of the above, R ¹² and R ¹³ are preferably a divalent aromatic ring group, and more preferably a substituted or unsubstituted phenylene group, in terms of being able to obtain a cured film having higher heat resistance, chemical resistance, and hardness, and in terms of being able to increase the solubility of the exposed area in an alkaline developer.

（式（２Ａ－１－１）、式（２Ａ－１－２）、式（２Ａ－２－１）、式（２Ａ－２－２）及び式（２Ａ－２－３）中、Ｒ^２１及びＲ^２２は、互いに独立して、炭素数１～４のアルキル基である。Ｒ^２３は、炭素数１～４のアルキル基、炭素数１～４のアルコキシ基又は水酸基である。ｎ３は１～４の整数である。Ａ^４、Ａ^５、ｍ１及びｍ２は、上記式（２－１）及び式（２－２）と同義である。Ｒ^Ｃは、上記式（２Ａ－１）及び式（２Ａ－２）と同義である。） Specific examples of the structural unit represented by formula (2A-1) include structural units represented by formulas (2A-1-1) and (2A-1-2) below. Specific examples of the structural unit represented by formula (2A-2) include structural units represented by formulas (2A-2-1), (2A-2-2) and (2A-2-3) below.

(In formulae (2A-1-1), (2A-1-2), (2A-2-1), (2A-2-2) and (2A-2-3), R ²¹ and R ²² are each independently an alkyl group having 1 to 4 carbon atoms. R ²³ is an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a hydroxyl group. n3 is an integer from 1 to 4. A ⁴ , A ⁵ , m1 and m2 are as defined above in formulae (2-1) and (2-2). R ^C is as defined above in formulae (2A-1) and (2A-2).)

Specific examples of the monomer constituting the second structural unit include compounds having a group represented by the above formula (2-1), such as styryltrimethoxysilane, styryltriethoxysilane, styrylmethyldimethoxysilane, styrylethyldiethoxysilane, styryldimethoxyhydroxysilane, styryldiethoxyhydroxysilane, 4-vinylphenyltrimethoxysilane, (meth)acryloxyphenyltrimethoxysilane, (meth)acryloxyphenyltriethoxysilane, (meth)acryloxyphenylmethoxydimethoxysilane, and (meth)acryloxyphenylethyldiethoxysilane;
Examples of the compound having a group represented by the above formula (2-2) include trimethoxy(4-vinylnaphthyl)silane, triethoxy(4-vinylnaphthyl)silane, methyldimethoxy(4-vinylnaphthyl)silane, ethyldiethoxy(4-vinylnaphthyl)silane, and (meth)acryloxynaphthyltrimethoxysilane;
Examples of the compound having a group represented by the above formula (2-3) include 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 4-(meth)acryloxybutyltrimethoxysilane, etc. Specific examples of the monomer constituting the second structural unit include, in addition to the above, vinyltrimethoxysilane, vinyltriethoxysilane, etc.

In the polymer component [A], the content of the second structural unit is 0.1 to 20% by mass relative to the total structural units constituting the polymer component [A]. If the content of the second structural unit is less than 0.1% by mass, the dielectric constant of the cured film obtained using this composition cannot be sufficiently reduced. If the content of the second structural unit is more than 20% by mass, the radiation sensitivity of this composition is poor. From the viewpoint of increasing the dielectric constant of the cured film, the content of the second structural unit in the polymer component [A] is preferably 0.5% by mass or more, more preferably 1% by mass or more. From the viewpoint of achieving both the sensitivity of this composition and the low dielectric constant and high transmittance of the cured film obtained, the content of the second structural unit is preferably 15% by mass or less, more preferably 10% by mass or less, relative to the total structural units constituting the polymer component [A].

(Other structural units)
The polymer component (A) may further include structural units (hereinafter also referred to as "other structural units") different from the first structural unit and the second structural unit. Examples of the other structural units include the third to fifth structural units shown below.

Third structural unit It is preferable that the polymer component [A] further contains at least one structural unit selected from the group consisting of structural units derived from maleimide and structural units having an acid group (excluding the first structural unit and the second structural unit; this is referred to as the "third structural unit"). By further containing the third structural unit in the polymer component [A], it is possible to increase the solubility (alkali solubility) of the polymer component [A] in an alkaline developer and to increase the curing reactivity.

When the third structural unit has an acid group, examples of the acid group include a carboxy group, a sulfonic acid group, a phenolic hydroxyl group, and an alcoholic hydroxyl group. Specifically, the third structural unit is preferably at least one selected from the group consisting of a structural unit having a carboxy group, a structural unit having a sulfonic acid group, a structural unit having a phenolic hydroxyl group, and a maleimide unit. In this specification, the term "phenolic hydroxyl group" refers to a hydroxyl group that is directly bonded to an aromatic ring (e.g., a benzene ring, a naphthalene ring, an anthracene ring, etc.).

The monomer that gives the third structural unit is not particularly limited, but is preferably an unsaturated monomer from the viewpoint of copolymerizability. Specific examples of monomers that give the third structural unit include unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, and 4-vinylbenzoic acid that give structural units having a carboxy group; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid; vinyl sulfonic acid, (meth)allyl sulfonic acid, styrene sulfonic acid, and (meth)acryloxyethyl sulfonic acid that give structural units having a sulfonic acid group; and 4-hydroxystyrene, o-isopropenylphenol, m-isopropenylphenol, p-isopropenylphenol, and hydroxyphenyl (meth)acrylate that give structural units having a phenolic hydroxyl group. Maleimide can also be used as a monomer that gives the third structural unit.

In the [A] polymer component, the content of the third structural unit is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, based on all structural units constituting the [A] polymer component, from the viewpoint of imparting good solubility in an alkaline developer. In addition, from the viewpoint of sufficiently generating a difference in solubility in an alkaline developer between the exposed and unexposed parts and obtaining a pattern with a good shape, the content of the third structural unit is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on all structural units constituting the [A] polymer component.

- Fourth structural unit It is preferable that the polymer component [A] further contains a structural unit having a crosslinkable group (excluding the first structural unit, the second structural unit, and the third structural unit. This is referred to as the "fourth structural unit".) By further containing the fourth structural unit in the polymer component [A], it is preferable in that the resolution and adhesion of the film obtained by using the present composition can be further improved.

The fourth structural unit may be a structural unit having one or more selected from the group consisting of an oxiranyl group and an oxetanyl group. In this specification, the term "epoxy group" encompasses both oxiranyl and oxetanyl groups. When the fourth structural unit has an epoxy group, this is preferable in that the epoxy group acts as a crosslinking group, thereby forming a cured film that has high chemical resistance and is inhibited from deteriorating over a long period of time.

（式（４－１）及び式（４－２）中、Ｒ^３０は、オキシラニル基又はオキセタニル基を有する１価の基である。Ｒ^Ｄは、水素原子、メチル基、ヒドロキシメチル基、シアノ基又はトリフルオロメチル基である。Ｘ^１は、単結合又は２価の連結基である。） The fourth structural unit is preferably a structural unit derived from an unsaturated monomer having an epoxy group, and specifically, is preferably at least one selected from the group consisting of a structural unit represented by the following formula (4-1) and a structural unit represented by the following formula (4-2).

(In formula (4-1) and formula (4-2), R ³⁰ is a monovalent group having an oxiranyl group or an oxetanyl group. R ^D is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. X ¹ is a single bond or a divalent linking group.)

In the above formulas (4-1) and (4-2), examples of R ³⁰ include an oxiranyl group, an oxetanyl group, a 3,4-epoxycyclohexyl group, a 3,4-epoxytricyclo[5.2.1.0 ^2,6 ]decyl group, and a 3-ethyloxetanyl group.

The divalent linking group for ^X1 is preferably a methylene group, an ethylene group, an alkanediyl group such as a 1,3-propanediyl group, or a divalent group in which any methylene group of an alkanediyl group is replaced with an oxygen atom.

Specific examples of the monomer having an epoxy group include glycidyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 2-(3,4-epoxycyclohexyl)ethyl (meth)acrylate, 3,4-epoxytricyclo[5.2.1.0 ^2,6 ]decyl (meth)acrylate, 2-hydroxyethyl methacrylate [3,4-epoxytricyclo(5.2.1.0 ^2,6 ) decan-9-yl], (3-methyloxetan-3-yl)methyl (meth)acrylate, (3-ethyloxetan-3-yl) (meth)acrylate, (oxetan-3-yl)methyl (meth)acrylate, 3-(meth)acryloyloxymethyl-3-ethyloxetane, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, and the like.

When the polymer component [A] contains a fourth structural unit, the content of the fourth structural unit in the polymer component [A] is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more, based on all structural units constituting the polymer component [A]. The content of the fourth structural unit is preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, based on all structural units constituting the polymer component [A]. By setting the content of the fourth structural unit within the above range, the film obtained using this composition exhibits better resolution, and the heat resistance and chemical resistance of the obtained cured film can be sufficiently increased, which is preferable.

Fifth structural unit The polymer component [A] may further contain a structural unit having an acid dissociable group (excluding the first structural unit, the second structural unit, the third structural unit and the fourth structural unit. This is referred to as the "fifth structural unit"). Unlike the first structural unit, the fifth structural unit does not have a partial structure represented by the above formula (1). The acid dissociable group of the fifth structural unit is preferably a group that substitutes a hydrogen atom of a carboxy group, an alcoholic hydroxyl group or a sulfonic acid group, and is a group that dissociates under the action of an acid. Among them, the fifth structural unit is preferably a structural unit in which the acid dissociable group is eliminated under the action of an acid to generate a carboxy group.

When the fifth structural unit is one in which an acid-dissociable group is eliminated by the action of an acid to generate a carboxyl group, examples of the fifth structural unit include structural units derived from protected unsaturated carboxylic acids. The unsaturated carboxylic acid is not particularly limited, and examples thereof include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, unsaturated acid anhydrides, and unsaturated polycarboxylic acids.

Specific examples of these include unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, α-chloroacrylic acid, cinnamic acid, 2-(meth)acryloyloxyethyl-succinic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxyethyl-phthalic acid, (meth)acrylic acid-2-carboxyethyl ester, and 4-vinylbenzoic acid. Unsaturated dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, and citraconic acid. Unsaturated acid anhydrides include maleic anhydride, itaconic anhydride, and citraconic anhydride. Unsaturated polycarboxylic acids include ω-carboxypolycaprolactone mono(meth)acrylate. Acid-dissociable groups include, for example, acetal functional groups, tertiary alkyl groups, tertiary alkyl carbonate groups, and trialkylsilyl groups. Among these, acetal functional groups are preferred because they are easily dissociated by acid.

（式（５－１）中、Ｒ^４１、Ｒ^４２及びＲ^４３は、次の（１）又は（２）を満たす。（１）Ｒ^４１は水素原子、炭素数１～１２のアルキル基又は炭素数３～２０の１価の脂環式炭化水素基である。Ｒ^４２及びＲ^４３は、互いに独立して、炭素数１～１２のアルキル基、炭素数３～２０の１価の脂環式炭化水素基、又は炭素数７～２０のアラルキル基である。（２）Ｒ^４１は、水素原子、炭素数１～１２のアルキル基又は炭素数３～２０の１価の脂環式炭化水素基である。Ｒ^４２及びＲ^４３は、互いに合わせられＲ^４２及びＯＲ^４３が結合する炭素原子とともに構成される環状エーテル構造を表す。「＊」は結合手を表す。） When the fifth structural unit has a carboxy group protected by an acetal functional group, the fifth structural unit preferably has an acetal ester structure of a carboxylic acid, and specifically, preferably has a group represented by the following formula (5-1):

(In formula (5-1), R ⁴¹ , R ⁴² and R ⁴³ satisfy the following (1) or (2). (1) R ⁴¹ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ⁴² and R ⁴³ are each independently an alkyl group having 1 to 12 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. (2) R ⁴¹ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ⁴² and R ⁴³ are combined together to represent a cyclic ether structure formed together with the carbon atoms to which R ⁴² and OR ⁴³ are bonded. "*" represents a bond.)

Specific and preferred examples of the group represented by R ⁴¹ , R ⁴² or R ⁴³ include the same groups as those explained as the group represented by R ⁷ , R ⁸ or R ⁹ in the above formula (Y-2).

Specific examples of the acetal ester structure of the carboxylic acid represented by the above formula (5-1) include a 1-methoxyethoxycarbonyl group, a 1-ethoxyethoxycarbonyl group, a 1-propoxyethoxycarbonyl group, a 1-butoxyethoxycarbonyl group, a 1-cyclohexyloxyethoxycarbonyl group, a 2-tetrahydrofuranyloxycarbonyl group, a 2-tetrahydropyranyloxycarbonyl group, and a 1-phenylmethoxyethoxycarbonyl group.

Specific examples of the fifth structural unit include structural units represented by the following formulas (5-1-1) to (5-1-6), in which R ^E is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group.

When the polymer component [A] contains a fifth structural unit, the content of the fifth structural unit in the polymer component [A] is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total structural units constituting the polymer component [A].

Other structural units include structural units derived from at least one monomer selected from the group consisting of (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having an alicyclic structure, (meth)acrylic acid esters having an aromatic ring structure, aromatic vinyl compounds, N-substituted maleimide compounds, vinyl compounds having a heterocyclic structure, conjugated diene compounds, nitrogen-containing vinyl compounds, and unsaturated dicarboxylic acid dialkyl ester compounds. By introducing these structural units into the polymer component [A], it is possible to adjust the glass transition temperature of the polymer component [A] and improve the pattern shape and chemical resistance of the resulting cured film.

Specific examples of monomers which provide other structural units that are different from the third to fifth structural units (hereinafter also referred to as "sixth structural unit") include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate;
Examples of (meth)acrylic acid esters having an alicyclic structure include cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, tricyclo[5.2.1.0 ^2,6 ]decan-8-yl (meth)acrylate, tricyclo[5.2.1.0 ^2,5 ]decan-8-yloxyethyl (meth)acrylate, and isobornyl (meth)acrylate;
Examples of (meth)acrylic acid esters having an aromatic ring structure include phenyl (meth)acrylate and benzyl (meth)acrylate;
Examples of aromatic vinyl compounds include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 5-t-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, diphenylethylene, vinylnaphthalene, and vinylpyridine;
Examples of N-substituted maleimide compounds include N-cyclohexylmaleimide, N-cyclopentylmaleimide, N-(2-methylcyclohexyl)maleimide, N-(4-methylcyclohexyl)maleimide, N-(4-ethylcyclohexyl)maleimide, N-(2,6-dimethylcyclohexyl)maleimide, N-norbornylmaleimide, N-tricyclodecylmaleimide, N-adamantylmaleimide, N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(4-ethylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, N-benzylmaleimide, and N-naphthylmaleimide.
Examples of vinyl compounds having a heterocyclic structure include tetrahydrofurfuryl (meth)acrylate, tetrahydropyranyl (meth)acrylate, 5-ethyl-1,3-dioxan-5-ylmethyl (meth)acrylate, 5-methyl-1,3-dioxan-5-ylmethyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, 2-(meth)acryloxymethyl-1,4,6-trioxaspiro[4,6]undecane, (γ-butyrolactone-2-yl) (meth)acrylate, glycerin carbonate (meth)acrylic acid, (γ-lactam-2-yl) (meth)acrylate, and N-(meth)acryloxyethylhexahydrophthalimide;
Conjugated diene compounds include 1,3-butadiene and isoprene;
Nitrogen-containing vinyl compounds include (meth)acrylonitrile and (meth)acrylamide;
Examples of the unsaturated dicarboxylic acid dialkyl ester compound include diethyl itaconate, etc. Examples of the monomers that provide other structural units include, in addition to the above, monomers such as vinyl chloride, vinylidene chloride, and vinyl acetate.

When the polymer component [A] further contains a sixth structural unit, the content of the sixth structural unit is preferably 5% by mass or more, and more preferably 10% by mass or more, based on all structural units constituting the polymer component [A], from the viewpoint of appropriately increasing the glass transition temperature of the polymer component [A]. The content of the sixth structural unit is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on all structural units constituting the polymer component [A].

[A] The polymer component can be produced, for example, by using an unsaturated monomer capable of introducing each of the structural units described above in a suitable solvent in the presence of a polymerization initiator, according to a known method such as radical polymerization. Examples of the polymerization initiator include azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(dimethylisobutyrate). The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass relative to 100 parts by mass of the total amount of monomers used in the reaction. Examples of the polymerization solvent include alcohols, ethers, ketones, esters, and hydrocarbons. The amount of the polymerization solvent used is preferably such that the total amount of the monomers used in the reaction is 0.1 to 60% by mass relative to the total amount of the reaction solution.

In the polymerization, the reaction temperature is usually 30°C to 180°C. The reaction time varies depending on the type of polymerization initiator and monomer and the reaction temperature, but is usually 0.5 to 10 hours. The polymer obtained by the polymerization reaction may be used for the preparation of the radiation-sensitive composition while still dissolved in the reaction solution, or may be used for the preparation of the radiation-sensitive composition after being isolated from the reaction solution. The polymer can be isolated by known isolation methods, such as a method of pouring the reaction solution into a large amount of poor solvent and drying the resulting precipitate under reduced pressure, or a method of distilling the reaction solution under reduced pressure using an evaporator.

The weight average molecular weight (Mw) of the polymer component [A] in terms of polystyrene measured by gel permeation chromatography (GPC) is preferably 2,000 or more. Mw of 2,000 or more is preferable in that a cured film having sufficiently high heat resistance and chemical resistance and good developability can be obtained. The Mw of the polymer component [A] is more preferably 5,000 or more, even more preferably 6,000 or more, and particularly preferably 7,000 or more. In addition, the Mw of the polymer component [A] is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 20,000 or less, and particularly preferably 15,000 or less, from the viewpoint of improving film formability.

The molecular weight distribution (Mw/Mn) of the polymer component [A], which is expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) converted into polystyrene by GPC, is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.5 or less. When the polymer component [A] is composed of two or more polymers, it is preferable that the Mw and Mw/Mn of each polymer satisfy the above ranges.

<[B] Photoacid generator>
The photoacid generator (B) is not particularly limited as long as it is a compound that generates an acid upon irradiation with radiation. Examples of the photoacid generator (B) include an oxime sulfonate compound, an onium salt, a sulfonimide compound, a halogen-containing compound, a diazomethane compound, a sulfone compound, a sulfonic acid ester compound, and a carboxylic acid ester compound.

Specific examples of oxime sulfonate compounds, onium salts, N-sulfonyloxyimide compounds, halogen-containing compounds, diazomethane compounds, sulfone compounds, sulfonate ester compounds, and carboxylate ester compounds include the compounds described in paragraphs 0078 to 0106 of JP 2014-157252 A and the compounds described in WO 2016/124493. [B] As the photoacid generator, it is preferable to use at least one selected from the group consisting of oxime sulfonate compounds and N-sulfonyloxyimide compounds from the viewpoint of radiation sensitivity.

（式（６）中、Ｒ^５０は、１価の炭化水素基、又は当該炭化水素基が有する水素原子の一部若しくは全部が置換基で置換された１価の基である。「＊」は結合手であることを表す。） The oxime sulfonate compound is preferably a compound having a sulfonate group represented by the following formula (6).

(In formula (6), R ⁵⁰ is a monovalent hydrocarbon group or a monovalent group in which some or all of the hydrogen atoms in the hydrocarbon group have been substituted with substituents. "*" represents a bond.)

In the above formula (6), examples of the monovalent hydrocarbon group represented by ^R50 include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, and an aryl group having 6 to 20 carbon atoms. Examples of the substituent include an alkoxy group having 1 to 5 carbon atoms, an oxo group, and a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), etc.

Examples of oxime sulfonate compounds include (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (5-octylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (camphorsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (5-p-toluenesulfonyloxyimino- Examples of the oxime sulfonate compound include 5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (2-[2-(4-methylphenylsulfonyloxyimino)]-2,3-dihydrothiophen-3-ylidene]-2-(2-methylphenyl)acetonitrile, 2-(octylsulfonyloxyimino)-2-(4-methoxyphenyl)acetonitrile, compounds described in International Publication No. 2016/124493, and compounds described in Japanese Patent No. 5914663. Examples of commercially available oxime sulfonate compounds include Irgacure PAG121 manufactured by BASF.

Examples of N-sulfonyloxyimide compounds include N-(trifluoromethylsulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, N-(4-methylphenylsulfonyloxy)succinimide, N-(2-trifluoromethylphenylsulfonyloxy)succinimide, N-(4-fluorophenylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(camphorsulfonyloxy)phthalimide, N-(2-trifluoromethylphenylsulfonyloxy)phthalimide, N-(2-fluorophenylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(camphorsulfonyloxy)diphenylmaleimide, 4-methylphenylsulfonyloxy)diphenylmaleimide, and trifluoromethanesulfonic acid-1,8-naphthalimide (N-hydroxynaphthalimide triflate).

The content of the photoacid generator [B] in the composition is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the polymer component [A]. The content of the photoacid generator [B] is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and preferably 5 parts by mass or less, relative to 100 parts by mass of the polymer component [A]. When the content of the photoacid generator [B] is 0.01 parts by mass or more, sufficient acid is generated by irradiation with radiation, and the difference in solubility between the exposed part and the unexposed part in the alkaline solution can be sufficiently increased. This allows good patterning to be performed. In addition, the amount of acid involved in the reaction with the polymer component [A] can be increased, and heat resistance and solvent resistance can be sufficiently ensured. On the other hand, by setting the content of the photoacid generator [B] to 20 parts by mass or less, the amount of unreacted photoacid generator [B] after exposure can be sufficiently reduced, and it is preferable in that the decrease in developability due to the remaining photoacid generator [B] can be suppressed.

<Other ingredients>
The composition may further contain, in addition to the polymer component [A] and the photoacid generator [B], a component different from the polymer component [A] and the photoacid generator [B] (hereinafter, also referred to as "other component"), such as an antioxidant [C], an acid diffusion controller [D], an orthoester compound [E], a crosslinking agent [F], an adhesion aid [G], and a solvent [F].

([C] Antioxidant)
The antioxidant [C] is a component that suppresses the cleavage of bonds in polymer molecules by capturing radicals generated by exposure or heating, or by decomposition of peroxides generated by oxidation. When the present composition contains the antioxidant [C], the cleavage deterioration of polymer molecules in the cured film is suppressed, which is preferable in that light resistance, etc. can be improved.

Examples of the antioxidant [C] include compounds having a hindered phenol structure, compounds having a hindered amine structure, compounds having an alkyl phosphite structure, and compounds having a thioether structure. Of these, it is preferable to include a compound having a hindered phenol structure as the antioxidant [C] because of its high effect of improving light resistance.

Specific examples of compounds having a hindered phenol structure include, for example, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), 3,3',3',5',5' -Hexa-tert-butyl-a,a',a'-(mesitylene-2,4,6-triyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, 4,6-bis(dodecylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate, hexamethylene bis[3-(3,5-di -tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamine)phenol, etc.

Commercially available compounds having a hindered phenol structure include, for example, Adeka STAB AO-20, AO-30, AO-40, AO-50, AO-60, AO-60G, AO-70, AO-80, and AO-330 (all manufactured by ADEKA Corporation); Sumilizer GM, GS, MDP-S, BBM-S, WX-R, and GA-80 (all manufactured by Sumitomo Chemical Co., Ltd.); and IRGANOX 1010. , 1035, 1076, 1098, 1135, 1330, 1726, 1425WL, 1520L, 245, 259, 3114, 565, IRGAMOD 295 (all manufactured by Ciba Japan); Yoshinox BHT, BB, 2246G, 425, 250, 930, SS, TT, 917, 314 (all manufactured by API Corporation).

When the present composition contains an antioxidant [C], the content of the antioxidant [C] in the present composition is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and preferably 0.1 parts by mass or more, per 100 parts by mass of the polymer component [A]. The content of the antioxidant [C] is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and preferably 5 parts by mass or less, per 100 parts by mass of the polymer component [A].

([D] Acid Diffusion Controller)
The acid diffusion controller [D] is a component that controls the diffusion length of the acid generated from the photoacid generator [B] upon exposure to light. By adding the acid diffusion controller [D] to the present composition, the diffusion length of the acid can be appropriately controlled, which is preferable in that the pattern developability can be improved.

[D] The acid diffusion control agent can be selected from any of the basic compounds used in chemically amplified resists. Examples of basic compounds include fatty acid amines, aromatic amines, heterocyclic amines, quaternary ammonium hydroxides, and quaternary ammonium carboxylates. Specific examples of basic compounds include the compounds described in paragraphs 0128 to 0147 of JP-A-2011-232632. [D] At least one selected from the group consisting of aromatic amines and heterocyclic amines can be preferably used as the acid diffusion control agent.

Examples of aromatic amines and heterocyclic amines include aniline derivatives such as aniline, N-methylaniline, N-ethylaniline, N-propylaniline, N,N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, ethylaniline, propylaniline, trimethylaniline, 2-nitroaniline, 3-nitroaniline, 4-nitroaniline, 2,4-dinitroaniline, 2,6-dinitroaniline, 3,5-dinitroaniline, and N,N-dimethyltoluidine; imidazole derivatives such as imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, triphenylimidazole, and N-(tert-butoxycarbonyl)-2-phenylbenzimidazole; pyrrole, 2H-pyrrole, 1-methylpyrrole, pyrrole derivatives such as pyridine, 2,4-dimethylpyrrole, 2,5-dimethylpyrrole, and N-methylpyrrole; pyridine derivatives such as pyridine, methylpyridine, ethylpyridine, propylpyridine, butylpyridine, 4-(1-butylpentyl)pyridine, dimethylpyridine, trimethylpyridine, triethylpyridine, phenylpyridine, 3-methyl-2-phenylpyridine, 3-methyl-4-phenylpyridine, 4-tert-butylpyridine, diphenylpyridine, benzylpyridine, methoxypyridine, butoxypyridine, dimethoxypyridine, 1-methyl-2-pyridone, 4-pyrrolidinopyridine, 1-methyl-4-phenylpyridine, 2-(1-ethylpropyl)pyridine, aminopyridine, dimethylaminopyridine, and nicotine, as well as compounds described in JP-A-2011-232632.

When the composition contains an acid diffusion control agent [D], the content of the acid diffusion control agent [D] is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, and even more preferably 0.01 parts by mass or more, relative to 100 parts by mass of the polymer component [A], from the viewpoint of obtaining a sufficient effect of improving the pattern developability by the acid diffusion control agent [D]. Furthermore, the content of the acid diffusion control agent [D] is preferably 10 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the polymer component [A].

([E] Orthoester Compound)
The orthoester compound [E] is a compound having a structure in which three groups represented by "-OR ⁶⁰ " (wherein R ⁶⁰ is a monovalent hydrocarbon group) are bonded to the same carbon, and is represented by the general formula: R ⁶¹ -C(OR ⁶⁰ ) _3. Here, R ⁶¹ is a hydrogen atom or a monovalent organic group. The orthoester compound [E] exhibits water absorption properties in the presence of acid, and is hydrolyzed to an ester. For this reason, by incorporating the orthoester compound [E] in the present composition, the water absorption action of the orthoester compound [E] is exhibited by the acid generated from the photoacid generator [B] (in other words, by irradiation with radiation), and the water absorption action of the orthoester compound [E] can improve the development adhesion of the coating film. In addition, the orthoester compound [E] is preferable in that it is stable and hydrophobic in an alkaline developer, and has little effect on unexposed areas (for example, on sensitivity).

Examples of the group represented by "-OR ⁶⁰ " include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a tert-butoxy group, an n-pentoxy group, a phenoxy group, and a methylphenyl group. Of these, the group represented by "-OR ⁶⁰ " is preferably an alkoxy group, more preferably an alkoxy group having 1 to 4 carbon atoms. Three groups "-OR ⁶⁰ " in the same molecule may be the same group or different groups.

Examples of R ⁶¹ include a hydrogen atom, a monovalent chain hydrocarbon group, a monovalent halogenated chain hydrocarbon group, a monovalent aromatic ring group, etc. Among these, R ⁶¹ is preferably a hydrogen atom, a monovalent chain hydrocarbon group, or a monovalent aromatic ring group, and specific examples thereof include a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms.

[E] Specific examples of orthoester compounds include triethyl orthochloroacetate, trimethyl orthoformate, triethyl orthoformate, tripropyl orthoformate, triisopropyl orthoformate, tributyl orthoformate, diethylphenyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, triethyl orthodichloroacetate, trimethyl orthobutyrate, triethyl orthobutyrate, trimethyl orthopropionate, triethyl orthopropionate, trimethyl orthovalerate, triethyl orthovalerate, trimethyl orthoisobutyrate, trimethyl orthobenzoate, and triethyl orthobenzoate.

[E] As the orthoester compound, among the above, a compound having an aromatic ring group can be preferably used since it can further increase the development adhesion of the coating film. Specific examples of orthoester compounds having an aromatic ring group include trimethyl orthobenzoate, triethyl orthobenzoate, and diethylphenyl orthoformate. Of these, trimethyl orthobenzoate and triethyl orthobenzoate are preferred since they have a high effect of improving the development adhesion of the coating film and can better maintain sensitivity.

In addition, as the orthoester compound [E], a compound having a boiling point higher than the prebake temperature can be preferably used. By using an orthoester compound having a boiling point sufficiently higher than the prebake temperature, the development adhesion of the coating film can be further improved. Specifically, the boiling point of the orthoester compound [E] is preferably 105°C or higher, more preferably 110°C or higher, and even more preferably 115°C or higher.

Specific examples of orthoester compounds having a boiling point of 105°C or higher include triethyl orthoformate, tripropyl orthoformate, tributyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, triethyl orthodichloroacetate, trimethyl orthobutyrate, trimethyl orthopropionate, triethyl orthopropionate, trimethyl orthovalerate, trimethyl orthobenzoate, and triethyl orthobenzoate. Note that in this specification, the boiling points are values at 1 atmosphere.

In the present composition, the content of the orthoester compound [E] is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 1 part by mass or more, relative to 100 parts by mass of the polymer component [A]. The content of the orthoester compound [E] is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the polymer component [A]. When the content of the orthoester compound [E] is 0.1 parts by mass or more, it is preferable in that the effect of improving the development adhesion of the coating film by having the orthoester compound [E] present in the film can be sufficiently obtained. When the content of the orthoester compound [E] is 30 parts by mass or less, it is preferable in that the decrease in sensitivity caused by the orthoester compound [E] can be suppressed.

([F] Crosslinking Agent)
As the crosslinking agent [F], at least one silane compound selected from the group consisting of silanol compounds and alkoxysilane compounds (hereinafter also referred to as "crosslinkable silane compound") can be preferably used. From the viewpoint of obtaining a film having a low dielectric constant and excellent development adhesion, the crosslinkable silane compound is preferably a compound represented by the following formula (7). In addition, the silane compound represented by the following formula (7) is preferred in that it is stable and hydrophobic in an alkaline developer and has little effect on unexposed areas (for example, effect on sensitivity).
(R ⁷⁰ ) _k Si(OR ⁷¹ ) _4-k ... (7)
(In formula (7), R ⁷⁰ is a hydrophobic group. R ⁷¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. k is an integer of 1 to 3. When a plurality of R ^70s are present, the plurality of R ^70s are the same or different. When a plurality of R ^71s are present, the plurality of R ^71s are the same or different.)

In the above formula (7), examples of the hydrophobic group represented by R ⁷⁰ include monovalent hydrocarbon groups and monovalent fluorinated hydrocarbon groups. Among these, the hydrophobic group represented by R ⁷⁰ is preferably a monovalent hydrocarbon group, such as a monovalent linear hydrocarbon group having 1 to 12 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and a monovalent aromatic hydrocarbon group having 1 to 12 carbon atoms. Among these, R ⁷⁰ is preferably a monovalent linear hydrocarbon group or a monovalent aromatic hydrocarbon group, and more preferably an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms.
R ⁷¹ is preferably a hydrogen atom, a methyl group or an ethyl group.
In the above formula (7), k is preferably 1 or 2, since this can enhance the effects of improving the development adhesion and lowering the dielectric constant of the cured film.

Specific examples of silanol compounds among the crosslinkable silane compounds include silanol compounds having a hydroxyl group, such as trimethylsilanol, ethyldimethylsilanol, diethylmethylsilanol, triethylsilanol, methylsilanetriol, diphenylsilanediol, phenylsilanetriol, triphenylsilanol, bis(4-tolyl)silanediol, and tris(4-tolyl)silanol.

Among the crosslinkable silane compounds, trifunctional alkoxysilane compounds include trimethoxy(methyl)silane, triethoxy(methyl)silane, methyltrippropoxysilane, tributoxy(methyl)silane, methyltriphenoxysilane, ethyltrimethoxysilane, triethoxy(ethyl)silane, ethyltrippropoxysilane, tributoxy(ethyl)silane, ethyltriphenoxysilane, trimethoxy(propyl)silane, triethoxy(propyl)silane, tripropoxy(propyl)silane, tributoxy(propyl)silane, and triphenoxy(propyl)silane. (butyl)silane, butyltrimethoxysilane, butyltriethoxysilane, butyltrippropoxysilane, tributoxy(butyl)silane, butyltriphenoxysilane, trimethoxy(phenyl)silane, triethoxy(phenyl)silane, phenyltrippropoxysilane, tributoxy(phenyl)silane, triphenoxy(phenyl)silane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclohexyltrippropoxysilane, cyclohexyltributoxysilane, cyclohexyltriphenoxysilane, and the like can be used.

Among the crosslinkable silane compounds, preferred bifunctional alkoxysilane compounds include dimethoxydimethylsilane, diethoxydimethylsilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, diisobutyldimethoxysilane, dicyclopentyldimethoxysilane, cyclohexyl(dimethoxy)methylsilane, cyclohexyldiethoxymethylsilane, dimethoxydiphenylsilane, diethoxydiphenylsilane, methylphenyldiethoxysilane, and dimethoxydiphenylsilane.

When forming a film using this composition, a coating film made of this composition is usually heated (prebaked) to remove the solvent components contained in this composition. Therefore, from the viewpoint of suppressing the volatilization of the crosslinkable silane compound during prebaking and leaving a large amount of the crosslinkable silane compound in the film after prebaking, a compound having a sufficiently high boiling point can be preferably used as the crosslinkable silane compound. Specifically, the boiling point of the crosslinkable silane compound is preferably 80°C or higher, more preferably 95°C or higher, even more preferably 120°C or higher, even more preferably 150°C or higher, and even more preferably 180°C or higher.

The crosslinkable silane compound to be blended in the composition can also be selected depending on the pre-bake temperature. Specifically, the boiling point of the crosslinkable silane compound is preferably at least 5°C higher than the pre-bake temperature, more preferably at least 10°C higher, even more preferably at least 20°C higher, even more preferably at least 30°C higher, and even more preferably at least 50°C higher.

Among the above crosslinkable silane compounds, compounds having aromatic rings are preferably used, because they have a high boiling point and are highly hydrophobic, and can improve the development adhesion and low dielectric constant of the cured film, and compounds having two or more aromatic rings in one molecule are more preferably used.

The molecular weight of the crosslinking agent [F] is preferably 90 or more, more preferably 100 or more, and even more preferably 150 or more. The molecular weight of the crosslinking agent [F] is preferably 500 or less, more preferably 450 or less, and even more preferably 400 or less. When the molecular weight of the crosslinking agent [F] is in the above range, it is advantageous in that it is possible to increase the development adhesion of the cured film while suppressing a decrease in the sensitivity and development solubility of the composition, and also to achieve a low dielectric constant.

In the present composition, the content of the crosslinking agent [F] is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 1 part by mass or more, relative to 100 parts by mass of the polymer component [A]. The content of the crosslinking agent [F] is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the polymer component [A]. When the content of the crosslinking agent [F] is 0.5 parts by mass or more, it is preferable in that the effect of improving the development adhesion and the dielectric constant of the coating film can be sufficiently obtained. When the content of the crosslinking agent [F] is 30 parts by mass or less, it is preferable in that the decrease in sensitivity caused by the crosslinking agent [F] can be suppressed.

([G] Adhesion Aid)
[G] the adhesion aid is a component that improves the adhesion between the cured film formed by using the composition and the substrate. [G] the adhesion aid is preferably a functional silane coupling agent having a reactive functional group. Examples of the reactive functional group of the functional silane coupling agent include a carboxy group, a (meth)acryloyl group, an epoxy group, a vinyl group, and an isocyanate group.

Specific examples of functional coupling agents include trimethoxysilylbenzoic acid, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

The content of the adhesion aid [G] in this composition is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less, per 100 parts by mass of the polymer component [A].

([H] Solvent)
The present composition is a liquid composition in which the polymer component [A], the photoacid generator [B], and other components that are optionally blended are dissolved or dispersed preferably in a solvent [H]. As the solvent [H], an organic solvent that dissolves each of the components blended in the present composition and does not react with each of the components is preferred.

[H] Specific examples of solvents include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; esters such as ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, and ethyl 3-ethoxypropionate; ethers such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, ethylene diglycol monomethyl ether, ethylene diglycol ethyl methyl ether, dimethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and diethylene glycol ethyl methyl ether; amides such as dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene. Of these, the solvent preferably contains at least one selected from the group consisting of ethers and esters, and more preferably contains at least one selected from the group consisting of ethylene glycol alkyl ether acetate, diethylene glycols, propylene glycol monoalkyl ether, and propylene glycol monoalkyl ether acetate.

Other components include, in addition to those mentioned above, for example, polyfunctional polymerizable compounds (polyfunctional (meth)acrylates, etc.), quinone diazide compounds, surfactants (fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, etc.), polymerization inhibitors, antioxidants, chain transfer agents, etc. The blending ratio of these components can be appropriately selected according to each component within a range that does not impair the effects of the present disclosure.

The solid content concentration of the present composition (the ratio of the total mass of the components other than the [H] solvent in the radiation-sensitive composition to the total mass of the radiation-sensitive composition) is appropriately selected in consideration of the viscosity, volatility, etc. The solid content concentration of the present composition is preferably in the range of 5 to 60 mass %. If the solid content concentration is 5 mass % or more, a sufficient thickness of the coating film can be ensured when the present composition is applied to a substrate. If the solid content concentration is 60 mass % or less, the thickness of the coating film does not become too large, and the viscosity of the radiation-sensitive composition can be appropriately increased, ensuring good coatability. The solid content concentration of the present composition is more preferably 10 to 55 mass %, and even more preferably 12 to 50 mass %.

<<Cured film and manufacturing method thereof>>
The cured film of the present invention is formed by the radiation-sensitive composition prepared as described above. The radiation-sensitive composition has high radiation sensitivity and excellent storage stability. In addition, by using the radiation-sensitive composition, a pattern film can be formed that exhibits high adhesion to a substrate even after development, has a low dielectric constant, and is excellent in chemical resistance. Therefore, the radiation-sensitive composition can be preferably used as a material for forming, for example, an interlayer insulating film, a planarizing film, a spacer, a protective film, a colored pattern film for a color filter, a partition wall, a bank, etc.

In producing a cured film, a positive cured film can be formed depending on the type of photosensitizer by using the above-mentioned radiation-sensitive composition. The cured film can be produced by using the above-mentioned radiation-sensitive composition, for example, by a method including the following steps 1 to 4.
(Step 1) A step of forming a coating film using the above-mentioned radiation-sensitive composition.
(Step 2) A step of exposing at least a portion of the coating film to light.
(Step 3) A step of developing the coating film after exposure.
(Step 4) A step of heating the developed coating film.
Each step will be described in detail below.

[Step 1: Coating step]
In step 1, the radiation-sensitive composition is applied to a surface on which a film is to be formed (hereinafter also referred to as the "film-forming surface"), and the solvent is preferably removed by a heat treatment (pre-bake) to form a coating film on the film-forming surface. The material of the film-forming surface is not particularly limited. For example, when forming an interlayer insulating film, the radiation-sensitive composition is applied to a substrate provided with switching elements such as TFTs to form a coating film. As the substrate, for example, a glass substrate, a silicon substrate, or a resin substrate is used. The surface of the substrate on which the coating film is to be formed may have a metal thin film formed according to the application, or may have been subjected to various surface treatments such as HMDS (hexamethyldisilazane) treatment.

Examples of methods for applying the radiation-sensitive composition include spraying, roll coating, spin coating, slit die coating, bar coating, and inkjet. Of these, spin coating, slit die coating, and bar coating are preferred. Pre-baking conditions vary depending on the type and content of each component in the radiation-sensitive composition, but are, for example, 60 to 130°C and 0.5 to 10 minutes. The thickness of the coating film formed (i.e., the film thickness after pre-baking) is preferably 0.1 to 12 μm. The radiation-sensitive composition applied to the surface to be coated may be dried under reduced pressure (VCD) before pre-baking.

[Step 2: Exposure step]
In step 2, radiation is irradiated to at least a part of the coating film formed in step 1. At this time, radiation is irradiated to the coating film through a mask having a predetermined pattern, thereby forming a cured film having a pattern. Examples of radiation include charged particle beams such as ultraviolet rays, far ultraviolet rays, visible light, X-rays, and electron beams. Among these, ultraviolet rays are preferred, and examples thereof include g-rays (wavelength 436 nm) and i-rays (wavelength 365 nm). The exposure dose of radiation is preferably 0.1 to 20,000 J/ ^m2 .

[Step 3: Development step]
In step 3, the coating film irradiated in step 2 is developed. Specifically, the coating film irradiated in step 2 is developed with a developer to remove the irradiated portion, thereby performing positive development. Examples of the developer include an aqueous solution of an alkali (basic compound). Examples of the alkali include sodium hydroxide, tetramethylammonium hydroxide, and the alkalis exemplified in paragraph [0127] of JP-A-2016-145913. From the viewpoint of obtaining appropriate developability, the alkali concentration in the aqueous alkali solution is preferably 0.1 to 5% by mass. Examples of the development method include a puddle method, a dipping method, a rocking immersion method, and a shower method. The development time varies depending on the composition of the composition, but is, for example, 30 to 120 seconds. After the development step, it is preferable to perform a rinse treatment by washing with running water on the patterned coating film.

[Step 4: Heating step]
In step 4, the coating film developed in step 3 is heated (post-baked). Post-baking can be performed using a heating device such as an oven or a hot plate. Regarding post-baking conditions, the heating temperature is, for example, 120 to 250° C. The heating time is, for example, 5 to 40 minutes when the heating treatment is performed on a hot plate, and 10 to 80 minutes when the heating treatment is performed in an oven. In this manner, a cured film having a desired pattern can be formed on a substrate. The shape of the pattern of the cured film is not particularly limited, and examples thereof include a line and space pattern, a dot pattern, a hole pattern, and a lattice pattern.

By curing this composition, a cured film having a sufficiently low dielectric constant of 3.3 or less can be obtained. The dielectric constant of the cured film is a value measured at a frequency of 10 kHz for the cured film obtained by irradiating this composition with ultraviolet light under conditions of an accumulated exposure of 9,000 J/ ^m2 and heating at 220°C for 1 hour. For details of the method for measuring the dielectric constant of the cured film, follow the method described in the examples below.

In addition, when the polymer component in the radiation-sensitive composition contains the first structural unit, it is considered that the acid-dissociable group (Y ¹ ) in the above formula (1) is eliminated by exposure to generate a hydroxyl group in the first structural unit, which leads to a high dielectric constant of the cured film. In this regard, it is considered that by introducing a relatively small amount of the second structural unit into the polymer component containing the first structural unit, the hydroxyl group generated in the first structural unit by exposure and the functional group in the second structural unit (specifically, the silanol group generated by exposure) are crosslinked, thereby forming a cured film with a low dielectric constant and high transparency. In addition, this is merely a guess and does not limit the present invention in any way.

<Semiconductor element>
The semiconductor element of the present disclosure includes a cured film formed using the present composition. The cured film is preferably an interlayer insulating film that insulates wiring in the semiconductor element. The semiconductor element of the present disclosure can be manufactured using a known method.

<Display element>
The display element of the present disclosure includes a cured film formed using the present composition. The display element of the present disclosure may include a semiconductor element of the present disclosure, thereby including a cured film formed using the present composition. Furthermore, the display element of the present disclosure may include a planarization film formed on a TFT substrate as a cured film formed using the present composition. Examples of the display element include a liquid crystal display element and an organic electroluminescence (EL) display element.

According to the present disclosure described above in detail, the following means are provided.
<Means 1> A radiation-sensitive composition comprising: [A] a polymer component including, in the same molecule or in different molecules, a first structural unit having a partial structure represented by the above formula (1) and a second structural unit having a partial structure represented by the above formula (2); and [B] a photoacid generator, the first structural unit being contained in an amount of 5 to 50 mass % and the second structural unit being contained in an amount of 0.1 to 20 mass % relative to all structural units of the polymer component.
<Measures 2> The radiation-sensitive composition according to <Measures 1>, wherein the photoacid generator is at least one selected from the group consisting of oxime sulfonate compounds and N-sulfonyloxyimide compounds.
<Measures 3> The radiation-sensitive composition according to <Measures 1> or <Measures 2>, wherein ^Y1 is represented by the above formula (Y-1), formula (Y-2) or formula (Y-3).
<Measures 4> The radiation-sensitive composition according to any one of <Measures 1> to <Measures 3>, wherein Ar ¹ is a substituted or unsubstituted phenylene group, naphthylene group, or anthrylene group.
<Measures 5> The radiation-sensitive composition according to any one of <Measures 1> to <Measures 4>, wherein the polymer component further contains at least one selected from the group consisting of a structural unit derived from maleimide and a structural unit having an acid group.
<Measures 6> The radiation-sensitive composition according to any one of <Measures 1> to <Measures 5>, wherein the polymer component further contains a structural unit having a crosslinkable group (excluding the first structural unit and the second structural unit).
<Measures 7> The radiation-sensitive composition according to any one of <Measures 1> to <Measures 6>, further comprising an orthoester compound.
<Measures 8> A cured film formed using the radiation-sensitive composition according to any one of <Measures 1> to <Measures 7>.
<Means 9> The cured film according to <Means 8>, having a relative dielectric constant of 3.3 or less at a frequency of 10 kHz.
<Means 10> A method for producing a cured film, comprising the steps of: forming a coating film using the radiation-sensitive composition according to any one of <Means 1> to <Means 7>; exposing at least a part of the coating film to light; developing the exposed coating film; and heating the developed coating film.
<Means 11> A semiconductor element comprising the cured film according to <Means 8>.
<Means 12> A display element comprising the cured film according to <Means 8>.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are based on mass unless otherwise specified. In the examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured by the following method.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
The Mw and Mn of the polymer were measured by the following method.
Measurement method: Gel permeation chromatography (GPC) method Apparatus: Showa Denko GPC-101
GPC column: Shimadzu GLC's GPC-KF-801, GPC-KF-802, GPC-KF-803 and GPC-KF-804 Mobile phase: Tetrahydrofuran Column temperature: 40°C
Flow rate: 1.0 mL/min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
・Detector: Differential refractometer ・Standard material: Monodisperse polystyrene

[Monomer]
The abbreviations of the monomers used in the synthesis of the polymer are as follows.
<<Monomer Providing the First Structural Unit>>
TMSPIPE: 4-isopropenylphenyloxytrimethylsilane TESPIPE: 4-isopropenylphenyloxytriethylsilane TMSPHS: 4-vinylphenyloxytrimethylsilane TMSOPMI: 4-trimethylsilyloxy-N-phenylmaleimide TMSOPMA: 4-trimethylsilyloxyphenyl methacrylate EOEPIPE: 1-(4-isopropenylphenyloxy)-1-ethoxyethane BocPIPE: (4-isopropenylphenyl)-(1,1-dimethylethyl)carbonate

<<Monomer Providing the Second Structural Unit>>
MPTMS: methacryloyloxypropyltrimethoxysilane APTMS: acryloyloxypropyltrimethoxysilane MPTES: methacryloyloxypropyltriethoxysilane STTMS: 4-vinylphenyltrimethoxysilane VTES: vinyltriethoxysilane

<<Monomer Providing the Third Structural Unit>>
MA: methacrylic acid MI: maleimide 4IPP: 4-isopropenylphenol HPMA: hydroxyphenyl methacrylate

<<Monomer Providing the Fourth Structural Unit>>
GA: Glycidyl acrylate GMA: Glycidyl methacrylate ECHMA: 3,4-epoxycyclohexylmethyl methacrylate OXMA: 3-methacryloyloxymethyl-3-ethyloxetane EDCPMA: 2-hydroxyethyl [3,4-epoxytricyclo(5.2.1.0^2,6)decan-9-yl] methacrylate

<<Monomer Providing the Fifth Structural Unit>>
TMSMA: Trimethylsilyl methacrylate M-THP: Tetrahydro-2H-pyran-2-yl methacrylate M-THF: 2-tetrahydrofuranyl methacrylate

Other Monomers
MMA: Methyl methacrylate CHMI: N-cyclohexylmaleimide PMI: N-phenylmaleimide ST: Styrene CHMA: Cyclohexyl methacrylate

<Synthesis of polymer component (A)>
[Synthesis Example 1] Synthesis of polymer (A-1) 10 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) and 200 parts of diethylene glycol methyl ethyl ether were charged into a flask equipped with a cooling tube and a stirrer. Subsequently, 15 parts of 4-isopropenylphenyloxytrimethylsilane, 5 parts of methacryloyloxypropyltrimethoxysilane, 15 parts of maleimide, 10 parts of glycidyl acrylate, 45 parts of methyl methacrylate, and 10 parts of N-cyclohexylmaleimide were charged, and after nitrogen replacement, the temperature of the solution was raised to 70°C while gently stirring, and this temperature was maintained for 5 hours to obtain a polymer solution containing polymer (A-1). The solid content concentration of this polymer solution was adjusted to 30% by mass. The Mw of polymer (A-1) was 10,500, and the molecular weight distribution (Mw/Mn) was 2.2.

Synthesis Examples 2 to 22, Comparative Synthesis Examples 1 to 5 Synthesis of Polymers (A-2) to (A-22), (CA-1) to (CA-5) Polymer solutions containing polymers having the same solid content concentration, weight average molecular weight, and molecular weight distribution as those of polymer (A-1) were obtained in the same manner as in Synthesis Example 1, except that the types and amounts (parts by mass) of each component shown in Table 1 were used.

<Preparation of Radiation-Sensitive Composition (1)>
The components used in preparing the radiation-sensitive composition are shown below.
{[A] Polymer component}
A-1 to A-22: Polymers (A-1) to (A-22) synthesized in Synthesis Examples 1 to 22
CA-1 to CA-5: Polymers (CA-1) to (CA-5) synthesized in Comparative Synthesis Examples 1 to 5

<<[B] Photoacid generator>>
B-1: NIT (N-hydroxynaphthalimide triflate)
B-2: Irgacure PAG121 (manufactured by BASF)
B-3: OS-17 described in International Publication No. WO 2016/124493
B-4: OS-25 described in International Publication No. 2016/124493
B-5: B-9 described in Japanese Patent No. 5914663

<<[C] Antioxidant>>
C-1: Adeka STAB AO-20 (manufactured by ADEKA Corporation)
C-2: Adeka STAB AO-60 (manufactured by ADEKA Corporation)
C-3: Adeka STAB AO-330 (manufactured by ADEKA Corporation)

"[D] Acid diffusion controller"
D-1: 2-phenylbenzimidazole D-2: N-(tert-butoxycarbonyl)-2-phenylbenzimidazole

<<[E] Orthoester compound>>
E-1: Trimethyl orthoformate E-2: Triethyl orthoacetate E-3: Trimethyl orthobenzoate

<<Crosslinking Agent (F)>>
F-1: Cyclohexyltrimethoxysilane F-2: Methylphenyldiethoxysilane F-3: Dimethoxydiphenylsilane F-4: Diphenylsilanediol F-5: Dicyclopentyldimethoxysilane F-6: Diisobutyldimethoxysilane

[Example 1]
To the polymer solution containing the polymer (A-1) obtained in Synthesis Example 1, 3 parts of a photoacid generator (B-1), 1 part of an antioxidant (C-1), 0.01 parts of an acid diffusion controller (D-1), 1 part of an orthoester compound (E-1), and 1 part of a crosslinking agent (F-1) were mixed in an amount equivalent to 100 parts (solid content) of the polymer (A-1), and diethylene glycol ethyl methyl ether and propylene glycol monomethyl ether were added in a mass ratio of 1:1 so that the final solid content concentration became 20 mass%. The mixture was then filtered through a membrane filter having a pore size of 0.2 μm to prepare a radiation-sensitive composition (S-1).

[Examples 2 to 25, Comparative Examples 1 to 5]
Radiation-sensitive compositions of Examples 2 to 25 and Comparative Examples 1 to 5 were prepared in the same manner as in Example 1, except that the types and blend amounts (parts by mass) of each component shown in Table 2 were used.

<Evaluation>
The radiation-sensitive compositions of Examples 1 to 25 and Comparative Examples 1 to 5 were evaluated for the following items by the methods described below. The evaluation results are shown in Table 3.

[Radiation Sensitivity]
Using a spinner, the radiation-sensitive composition was applied onto a silicon substrate that had been HMDS-treated at 60° C. for 60 seconds, and then prebaked on a hot plate at 90° C. for 2 minutes to form a coating film with an average thickness of 3.0 μm. This coating film was irradiated with a predetermined amount of ultraviolet light from a mercury lamp through a pattern mask having a line-and-space pattern with a width of 10 μm. Next, a development process was performed at 25° C. for 60 seconds using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide as a developer, and then washing was performed with running ultrapure water for 1 minute. At this time, the minimum exposure amount capable of forming a line-and-space pattern with a width of 10 μm was measured, and the radiation sensitivity was evaluated based on the minimum exposure amount. The evaluation criteria are as follows.
◯: The measured value of the minimum exposure is less than 300 J/ ^m2 , and the radiation sensitivity is good. ×: The measured value of the minimum exposure is 300 J/ ^m2 or more, and the radiation sensitivity is poor.

[Dielectric constant]
A radiation-sensitive composition was applied onto a SUS304 substrate whose surface had been smoothed by polishing with a sisal buff (hemp buff), and the ultimate pressure was set to 100 Pa to remove the solvent under vacuum. The substrate was then prebaked at 90°C for 2 minutes to form a coating film having an average thickness of 3.0 μm. The coating film thus obtained was exposed to light with an exposure machine (Canon's "MPA-600FA") so that the cumulative exposure dose was 9,000 J/ ^m2 , and the substrate having the coating film after exposure was heated in a clean oven at 220°C for 1 hour to form an insulating film on the substrate. A Pt/Pd electrode pattern was formed on the insulating film by deposition to prepare a sample for measuring the dielectric constant. The substrate having this electrode pattern was subjected to measurement of the relative dielectric constant by the CV method at a frequency of 10 kHz using an HP16451B electrode and an HP4284A precision LCR meter manufactured by Yokogawa-Hewlett-Packard Co. The evaluation criteria are as follows.
○: Measured value is 3.3 or less ×: Measured value exceeds 3.3

[Transmittance (transparency)]
The radiation-sensitive composition was applied onto a glass substrate using a spinner, and then prebaked on a hot plate at 90°C for 2 minutes to form a coating film with a thickness of 3.0 μm. The coating film obtained was irradiated with ultraviolet light from a mercury lamp so that the cumulative exposure dose was 3,000 J/ ^m2 . The glass substrate was then heated on a hot plate at 200°C for 30 minutes to obtain a cured film. The transmittance of the cured film obtained was measured using a UV-visible spectrophotometer ("V-630" manufactured by JASCO Corporation). The evaluation criteria were as follows:
◯: The transmittance of light having a wavelength of 400 nm is 97% or more, and the transparency is good. ×: The transmittance of light having a wavelength of 400 nm is less than 97%, and the transparency is poor.

[Storage stability]
The prepared radiation-sensitive composition was sealed in a light-shielding, airtight container. After 7 days at 25°C, the container was opened, and the composition was irradiated with the minimum exposure amount capable of forming a line-and-space pattern with a width of 10 μm, which was determined by the measurement of [Radiation Sensitivity] before storage, in the same manner as in the above [Radiation Sensitivity], and the increase rate of the line width for the same exposure amount before and after storage for 7 days was calculated. The evaluation criteria are as follows.
○: The increase is less than 10%, and the storage stability is good. ×: The increase is 10% or more, and the storage stability is poor.

[Outgassing characteristics]
Using a spinner, the radiation-sensitive composition was applied onto a silicon substrate, and then prebaked on a hot plate at 90°C for 2 minutes to form a coating film with an average thickness of 3.0 μm. Furthermore, the substrate was baked for 30 minutes using an oven heated to 230°C to form a cured film. Next, the silicon substrate was cut to a size of 1 cm x 5 cm, and then baked for 15 minutes at 230°C using a P&T-GCMS device consisting of a JTD-505 manufactured by Japan Analytical Industry Co., Ltd. and a GC-QP-2010 manufactured by Shimadzu Corporation to obtain a chromatogram. The amount of outgassing was calculated from the following formula (I) using the peak area of C18 in the chromatogram when the cured film was used as the measurement sample and the peak area of the chromatogram of standard sample C18 measured separately using the same device. In the following formula (I), the "introduced amount of standard sample" refers to the introduced amount of standard sample introduced into the device when obtaining the chromatogram of standard sample C18.
Amount of outgassing (μg)=(peak area of chromatogram of cured film/peak area of chromatogram of standard sample)×amount of standard sample introduced (μg) (I)
The calculated outgassing amount was used to evaluate the outgassing characteristics according to the following criteria.
○: The amount of outgassing is less than 10 μg, and the outgassing characteristics are good. ×: The amount of outgassing is 10 μg or more, and the outgassing characteristics are poor.

[Pattern shape (taper shape)]
Using a spinner, the radiation-sensitive composition was applied onto a silicon substrate that had been HMDS-treated at 60° C. for 60 seconds, and then prebaked on a hot plate at 90° C. for 2 minutes to form a coating film with an average thickness of 3.0 μm. A predetermined amount of ultraviolet light was irradiated onto this coating film using a pattern mask having a line-and-space pattern with a width of 10 μm from a mercury lamp. Next, a development process was performed at 25° C. for 60 seconds using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide as a developer, and then washing was performed with running ultrapure water for 1 minute. Furthermore, the substrate was baked for 30 minutes using an oven heated to 230° C. to form a cured film. After cutting the silicon substrate into a size of 1 cm×1 cm, the cross-sectional shape of the line-and-space pattern was observed using a scanning electron microscope Regulus 8100 manufactured by Hitachi High-Tech Corporation, and the taper angle was determined. The pattern shape was evaluated according to the following criteria based on the taper angle.
◯: The taper angle is 50 degrees or more and the taper shape is good. ×: The taper angle is less than 50 degrees and the taper shape is poor.

As shown in Table 3, the radiation-sensitive compositions of Examples 1 to 25 were evaluated as having good practical properties in terms of radiation sensitivity, relative dielectric constant, transmittance, storage stability, outgassing characteristics, and pattern shapeability, and the various properties were well-balanced. In contrast, the films of Comparative Examples 1 to 3 had low relative dielectric constants, and Comparative Example 1 also had poor pattern shapeability. Furthermore, Comparative Example 4 had low film transmittance, and Comparative Example 5 had poor radiation sensitivity and pattern shapeability.

Claims (10)

[A] a polymer component including, in the same molecule or in different molecules, a first structural unit having a partial structure represented by the following formula (1) and a second structural unit having a partial structure represented by the following formula (2):
[B] a photoacid generator;
Contains
The polymer component contains 10 to 40 % by mass of the first structural unit and 1 to 20% by mass of the second structural unit , based on the total structural units of the polymer component;
The first structural unit is at least one selected from the group consisting of a structural unit represented by the following formula (1-1A), a structural unit represented by the following formula (1-2A), a structural unit represented by the following formula (1-1B), a structural unit represented by the following formula (1-2B), a structural unit derived from 4-trimethylsilyloxy-N-phenylmaleimide, and a structural unit derived from 4-trimethylsilyloxyphenyl(meth)acrylate,
The second structural unit is at least one selected from the group consisting of a structural unit represented by the following formula (2A-1) and a structural unit represented by the following formula (2A-2):
the polymer component further includes a third structural unit which is at least one selected from the group consisting of a structural unit derived from maleimide, a structural unit having a carboxy group, a structural unit having a sulfonic acid group, and a structural unit having a phenolic hydroxyl group;
a radiation-sensitive composition comprising the third structural unit in an amount of 1 to 30% by mass based on the total structural units of the polymer component ;

(In formula (1), ^Ar1 is a divalent aromatic ring group. ^Y1 is an acid dissociable group. n is 0 or 1. "*" represents a bond. However, when n is 0, the first structural unit is a structural unit derived from a monomer having a maleimide ring, and Y1 is ^bonded to a nitrogen atom of the maleimide ring. )

(In formula (2), R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a phenyl group. However, at least one of R ¹ , R ² and R ³ is an alkoxy group having 1 to 6 carbon atoms. "*" represents a bond bonded to a carbon atom.)

(In formula (1-1A) and formula (1-2A), R ^A is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. R ⁴ , R ⁵ , and R ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxy group, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a group in which some or all of the hydrogen atoms of the hydrocarbon group have been substituted with a substituent. A ¹ and A ² are each independently a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n1 is an integer from 0 to 4. n2 is an integer from 0 to 6. However, when n1 is 2 or more, multiple A ¹ 's are the same or different groups. When n2 is 2 or more, multiple A ² 's are the same or different groups.)

(In formulas (1-1B) and (1-2B), R ⁷ , R 8 , and R 9 represent a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. R 7 , R ⁸ , ^and R ⁹ represent the following (1) or (2). (1) R ⁷ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ⁸ and R ⁹ represent each other independently an alkyl group having 1 to 12 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. (2) R ⁷ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ⁸ and R ⁹ represent each other together to represent a cyclic ether structure formed together with the carbon atoms to which R ⁸ and OR ⁹ are bonded. R ¹⁰ represents a tertiary alkyl group. ³ is a halogen atom, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. n3 is an integer from 0 to 4.

(In formula (2A-1) and formula (2A-2), R ^C is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. R ¹² is a divalent aromatic ring group or a chain hydrocarbon group. R ¹³ is a single bond, a divalent aromatic ring group, or a chain hydrocarbon group. R ¹ , R ² , and R ³ are each defined as in formula (2) above.) The radiation-sensitive composition according to claim 1, wherein the photoacid generator is at least one selected from the group consisting of oxime sulfonate compounds and N-sulfonyloxyimide compounds. The radiation-sensitive composition according to claim 1 , wherein the third structural unit is a structural unit derived from maleimide. The radiation-sensitive composition according to claim 1 , wherein the polymer component further comprises a structural unit having a crosslinkable group (excluding the first structural unit , the second structural unit , and the third structural unit ). The radiation-sensitive composition according to claim 1, further comprising an orthoester compound. A cured film formed using the radiation-sensitive composition according to any one of claims 1 to 5 . The cured film according to claim 6 , which has a dielectric constant of 3.3 or less at a frequency of 10 kHz. A step of forming a coating film using the radiation-sensitive composition according to any one of claims 1 to 5 ;
exposing at least a portion of the coating to light;
developing the coating film after exposure;
heating the developed coating;
The method for producing a cured film comprising the steps of: A semiconductor device comprising the cured film according to claim 6 . A display device comprising the cured film according to claim 6 .