Photosensitive composition, cured film and manufacturing method thereof, and display device

Abstract

To provide a photosensitive composition that allows formation of a cured film having high sensitivity along with excellent heat resistance, bending resistance, and reworkability.SOLUTION: A photosensitive composition comprises a polymer component and a quinonediazide compound, wherein the polymer component includes a polymer (A) having a first structural unit and a second structural unit, the first structural unit having a cyclic ether structure and a methylene group bonded to a carbon atom constituting the cyclic ether structure in a main chain, the second structural unit being at least one selected from the group consisting of a structural unit derived from maleimide and a structural unit having an acid group, and the polymer (A) is contained in an amount of 25 mass% or more relative to the total amount of the polymer component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photosensitive composition, a cured film and a method for producing the same, and a display device. [Background technology]

[0002] Various display devices equipped with organic electroluminescence elements (organic EL elements) or liquid crystal display elements are provided with insulating cured films such as planarizing films, interlayer insulating films, and bank materials (also called partition walls). In recent years, these cured films have been formed using photosensitive compositions containing a polymer component and a photosensitive compound. For example, a patterned cured film can be obtained by irradiating a coating film formed from the photosensitive composition with radiation through a mask having a pattern, followed by a development process, and then by heat treatment for thermal curing (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses that a cured film for an organic EL display device is formed from a photosensitive resin composition containing a polyimide precursor as an alkali-soluble resin and a quinone diazide compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-157173 Summary of the Invention [Problem to be solved by the invention]

[0005] A cured film formed from a photosensitive composition having a polyimide precursor or a polyimide as a base resin has excellent heat resistance, but its sensitivity is insufficient, and there is room for further improvement.

[0006] Furthermore, during the manufacturing process of a cured film, defects such as pinholes and uneven coating may occur in the film formed on the substrate. For this reason, the cured film once formed is often peeled off from the substrate and the substrate is reused (reworked). During such reworking, it is required that the film can be easily peeled off from the substrate by contacting the film with a solvent (i.e., good reworkability). However, polyimides generally have low solubility and poor reworkability.

[0007] In recent years, the use of flexible displays that can be deformed into various shapes, such as by bending or folding, using flexible substrates such as resin films has been considered for devices such as smartphones equipped with organic light-emitting diode (OLED) displays. Therefore, cured films for display devices are sometimes required to have bending resistance (hereinafter also referred to as "bending resistance") that can be used for flexible displays.

[0008] The present invention has been made in view of the above-mentioned problems, and a main object of the present invention is to provide a photosensitive composition that has high sensitivity and is capable of forming a cured film that has excellent heat resistance, bending resistance, and reworkability. [Means for solving the problem]

[0009] According to the present invention, there are provided the following photosensitive composition, cured film and method for producing the same, and display device.

[0010] [1] A photosensitive composition containing a polymer component and a quinone diazide compound, wherein the polymer component includes a polymer (A) having a first structural unit and a second structural unit, the first structural unit having a cyclic ether structure and a methylene group bonded to a carbon atom constituting the cyclic ether structure in a main chain, and the second structural unit is at least one selected from the group consisting of a structural unit derived from maleimide and a structural unit having an acid group, and the photosensitive composition contains the polymer (A) in an amount of 25 mass% or more based on the total amount of the polymer component. [2] A cured film formed from the photosensitive composition described in [1] above. [3] A method for producing a cured film, comprising: a film-forming step of forming a coating film using the photosensitive composition described in [1] above; an exposure step of exposing at least a part of the coating film to light; a development step of developing the exposed coating film; and a heating step of heating the developed coating film. [4] A display device comprising the cured film according to [2] above. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain a photosensitive composition which has high sensitivity and is capable of forming a cured film which is excellent in heat resistance, bending resistance and reworkability. DETAILED DESCRIPTION OF THE INVENTION

[0012] Matters related to the embodiments will be described in detail below. In this specification, a numerical range indicated using "to" means that the numerical values before and after "to" are included as the lower and upper limits.

[0013] As used herein, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. The term "chain hydrocarbon group" refers to a linear hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed solely of a chain structure. However, the chain hydrocarbon group may be saturated or unsaturated. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, the alicyclic hydrocarbon group does not necessarily have to be composed solely of an alicyclic hydrocarbon structure, and also includes groups that have a chain structure as part of it. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not necessarily have to be composed solely of an aromatic ring structure, and may contain a chain structure or an alicyclic hydrocarbon structure as part of it. The ring structures of the alicyclic hydrocarbon group and the aromatic hydrocarbon group may have a substituent group composed of a hydrocarbon structure.

[0014] A "structural unit" refers to a unit that primarily constitutes the main chain structure, and at least two or more units are contained in the main chain structure. The "main chain" of a polymer refers to the "trunk" portion of the polymer, which is made up of the longest chain of atoms. It is permissible for this "trunk" portion to contain a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. A "side chain" refers to a portion branched from the "trunk" portion of the polymer. "(Meth)acrylic" is a term that encompasses "acrylic" and "methacrylic".

[0015] 《Photosensitive composition》 The photosensitive composition of the present disclosure (hereinafter also referred to as "the composition") contains a polymer component and a quinone diazide compound. Each component contained in the composition, as well as other components that may be blended as needed, will be described below.

[0016] <Polymer component> The present composition contains, as a polymer component, a polymer (A) having the first structural unit and the second structural unit shown below. First structural unit: a structural unit having, in the main chain, a cyclic ether structure and a methylene group bonded to a carbon atom constituting the cyclic ether structure Second structural unit: at least one structural unit selected from the group consisting of a structural unit derived from maleimide and a structural unit having an acid group

[0017] (Polymer (A)) First structural unit The cyclic ether structure of the first structural unit preferably has 5 or 6 ring members, and specific examples include a tetrahydrofuran ring structure or a tetrahydropyran structure. The first structural unit may have a partial structure in which a cyclic ether structure and a methylene group bonded to a carbon atom constituting the cyclic ether structure are introduced into the polymer main chain. A preferred specific example is a repeating unit in which the methylene groups constituting the polymer main chain of the first structural unit are one or two per first structural unit, and the main chain portion of the polymer constituted by the first structural unit is a structure consisting of a cyclic ether structure and one or two methylene groups. The cyclic ether structure of the first structural unit may have a substituent on the ring portion.

[0018] More specifically, the first structural unit is preferably a structural unit represented by the following formula (1). [ka] (In formula (1), R 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms. 2 is a hydrogen atom or -COOR 3 R 3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms, and n is 0 or 1.

[0019] In the above formula (1), R 1 or R 3 Examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms represented by the formula (I) include linear or branched saturated hydrocarbon groups having 1 to 30 carbon atoms, linear or branched unsaturated hydrocarbon groups having 2 to 30 carbon atoms, alicyclic hydrocarbon groups having 3 to 30 carbon atoms, and aromatic hydrocarbon groups having 6 to 30 carbon atoms.

[0020] Specific examples of linear or branched saturated hydrocarbon groups having 1 to 30 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups. Specific examples of linear or branched unsaturated hydrocarbon groups having 2 to 30 carbon atoms include alkenyl groups such as ethenyl, 1-propenyl, 2-propenyl, 1-butenyl, and 2-butenyl groups; and alkynyl groups such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, and 2-butynyl groups.

[0021] Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include groups having, as a ring structure, an alicyclic monocyclic hydrocarbon structure having 3 to 30 carbon atoms or an alicyclic polycyclic hydrocarbon structure having 6 to 30 carbon atoms. The alicyclic monocyclic hydrocarbon structure having 3 to 30 carbon atoms and the alicyclic polycyclic hydrocarbon structure having 6 to 30 carbon atoms may be saturated or unsaturated. Specific examples of the ring contained in the alicyclic hydrocarbon group include a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, a cyclooctene ring, a cyclodecene ring, a norbornane ring, a bicyclo[2.2.2]octane ring, and an adamantane ring.

[0022] Examples of aromatic hydrocarbon groups having 6 to 30 carbon atoms include groups having, as a ring structure, an aromatic monocyclic hydrocarbon structure having 6 to 30 carbon atoms or an aromatic polycyclic hydrocarbon structure having 6 to 30 carbon atoms. Specific examples of the ring contained in the aromatic hydrocarbon group include a benzene ring, a naphthalene ring, an anthracene ring, an indene ring, and a fluorene ring.

[0023] R 1 or R 3 Among the above, each of is preferably a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

[0024] Specific examples of the first structural unit include structural units represented by the following formulas (1-1) to (1-11). [ka]

[0025] For example, the structural unit represented by the above formula (1) can be introduced into a polymer by polymerization using a diene compound represented by the following formula (1A) as a monomer. Preferred specific examples of the diene compound include 2-(allyloxymethyl)methyl (meth)acrylate, 2-(allyloxymethyl)ethyl (meth)acrylate, and 2-(allyloxymethyl)n-propyl (meth)acrylate. [ka] (In formula (1A), R 1 and R 2 is the same as the above formula (1).

[0026] The content of the first structural unit in the polymer (A) is preferably 1 to 60% by mass, based on all structural units constituting the polymer (A). By setting the content of the first structural unit within the above range, a cured film with superior heat resistance and bending resistance can be obtained. From the viewpoint of obtaining a cured film with superior heat resistance and bending resistance, the content of the first structural unit in the polymer (A) is more preferably 2% by mass or more, and even more preferably 5% by mass or more. Furthermore, from the viewpoint of preventing the composition from melting and causing pattern collapse when heated (post-baked) at a relatively high temperature during film formation, the content of the first structural unit is more preferably 55% by mass or less, and even more preferably 50% by mass or less, based on all structural units constituting the polymer (A).

[0027] Second structural unit The second structural unit is at least one selected from the group consisting of structural units derived from maleimide and structural units having an acid group (excluding the first structural unit). When the polymer (A) further has the second structural unit, the solubility (alkali solubility) of the polymer (A) in an alkaline developer and the curing reactivity can be increased.

[0028] Examples of the acid group include a carboxy group, a sulfonic acid group, a phenolic hydroxyl group, etc. 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, a phenanthrene ring, etc.).

[0029] Specifically, the second 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 order to further enhance the alkali solubility of the polymer (A), the polymer (A) preferably has, as the second structural unit, at least one selected from the group consisting of a structural unit having a carboxy group, a structural unit having a sulfonic acid group, and a maleimide unit (hereinafter also referred to as "structural unit 2A"), and more preferably at least one selected from the group consisting of a structural unit having a carboxy group and a maleimide unit. Of these, the maleimide unit is preferred in that it can enhance storage stability.

[0030] The monomer that provides the structural unit 2A is not particularly limited as long as it is copolymerizable with the monomer that provides the first structural unit. Specific examples of the monomer that provides the structural unit 2A include monomers that provide structural units having a carboxy group, such as unsaturated monocarboxylic acids (e.g., (meth)acrylic acid, crotonic acid, 4-vinylbenzoic acid), and unsaturated dicarboxylic acids (e.g., maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid), and monomers that provide structural units having a sulfonic acid group, such as vinyl sulfonic acid, (meth)allyl sulfonic acid, styrene sulfonic acid, and (meth)acryloxyethyl sulfonic acid. Maleimide can also be used as the monomer that provides the structural unit 2A.

[0031] In order to enhance the sensitivity of the composition while imparting alkaline developability, it is preferable that polymer (A) has a structural unit having a phenolic hydroxyl group (hereinafter also referred to as "structural unit 2B") as the second structural unit. Preferred specific examples of structural unit 2B include structural units represented by the following formula (2-1) and structural units represented by the following formula (2-2). [ka] (In formula (2-1) and formula (2-2), R A is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. 1 is a single bond, * 1 -COO-, * 1 -CO-NH-, * 1 -COO-R B -or* 1 -CO-NH-R B -R B is an alkanediyl group having 1 to 12 carbon atoms. 1 is R A represents the bond to the carbon atom. 1is a monovalent hydrocarbon group having 1 to 12 carbon atoms, a monovalent oxyhydrocarbon group having 1 to 12 carbon atoms, or a halogen atom. m1 is an integer of 1 to 5. m2 is an integer of 1 to 7. n1 is an integer of 0 to 4. n2 is an integer of 0 to 6, provided that m1+n1≦5 and m2+n2≦7. When n1 is 2 or more, multiple A 1 are the same or different. If n2 is 2 or more, multiple A 1 are the same or different.)

[0032] In the above formula (2-1) and formula (2-2), the position of the hydroxyl group bonded to the benzene ring or naphthalene ring is not particularly limited. For example, the position of the hydroxyl group bonded to the benzene ring in the above formula (2-1) is 1 In order to increase the difference in solubility between the exposed and unexposed areas, m1 and m2 each preferably represent an integer of 1 to 3, and more preferably 1 or 2.

[0033] Specific examples of the structural unit 2B include structural units represented by the following formulas. [ka]

[0034] Specific examples of monomers that provide the structural unit 2B include 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 2-methyl-4-hydroxystyrene, 3-methyl-2-hydroxystyrene, 3,4-dihydroxystyrene, o-isopropenylphenol, m-isopropenylphenol, p-isopropenylphenol, 2-hydroxy-6-vinylnaphthalene, 1-hydroxy-4-vinylnaphthalene, 2-hydroxyphenyl(meth)acrylate, 3-hydroxyphenyl(meth)acrylate, 4-hydroxyphenyl(meth)acrylate, 3-hydroxynaphthyl(meth)acrylate, and 4-hydroxyphenyl(meth)acrylate.

[0035] In the polymer (A), the content of the second structural unit is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, based on all structural units constituting the polymer (A), from the viewpoint of imparting good solubility in an alkaline developer to the polymer. Furthermore, from the viewpoint of sufficiently generating a difference in solubility in an alkaline developer between exposed and unexposed areas and obtaining a pattern with a good shape, the content of the second 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 polymer (A).

[0036] From the viewpoint of imparting good solubility in an alkaline developer, the content of the structural unit 2A is preferably 0.2% 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 (A). From the viewpoint of obtaining a pattern with a good shape, the content of the structural unit 2A 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 all structural units constituting the polymer (A).

[0037] The polymer (A) preferably has structural unit 2A and structural unit 2B as the second structural unit. The combined use of structural unit 2A and structural unit 2B can increase radiation sensitivity compared to using structural unit 2A alone. The content of structural unit 2B is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 2% by mass or more, based on the total structural units constituting polymer (A), in order to impart good solubility in alkaline developers while sufficiently increasing the sensitivity of the composition. Furthermore, in order to obtain a pattern with a good shape, the content of structural unit 2B is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, based on the total structural units constituting polymer (A).

[0038] Other structural units The polymer (A) may further contain structural units different from the first structural unit and the second structural unit (hereinafter also referred to as "other structural units"). Examples of the other structural units include the structural units shown below.

[0039] Preferably, the polymer (A) further contains a structural unit having an oxiranyl group or an oxetanyl group (hereinafter, this will be referred to as the "third structural unit"). Here, while the introduction of the first structural unit into the polymer can improve the bending resistance of the cured film formed from this composition, the introduction of a methylene group into the polymer main chain is thought to make the film more likely to melt during the heating step (post-baking) during film formation. In this regard, by introducing the third structural unit into the polymer together with the first structural unit, a crosslinked structure can be formed between or within the molecules of the polymer (A), thereby preventing the film from melting even when heated at a relatively high temperature during film formation.

[0040] The third structural unit is preferably a structural unit derived from an unsaturated monomer having an oxiranyl group or an oxetanyl group, and more specifically, is preferably at least one selected from the group consisting of structural units represented by the following formula (3-1) and structural units represented by the following formula (3-2): [ka] (In formula (3-1) and formula (3-2), R D is a hydrogen atom, a methyl group, a hydroxymethyl group, a cyano group, or a trifluoromethyl group. 30 is a monovalent group having an oxiranyl group or an oxetanyl group. 2 R is a single bond or a divalent linking group. 31 is a monovalent hydrocarbon group having 1 to 12 carbon atoms, a monovalent oxyhydrocarbon group having 1 to 12 carbon atoms, or a halogen atom. k is an integer of 0 to 4. When k is 2 or more, multiple R 31 are the same or different.)

[0041] In the above formula (3-1) and formula (3-2), R 30 Examples include oxiranyl, oxetanyl, 3,4-epoxycyclohexyl, and 3,4-epoxytricyclo[5.2.1.0 2,6 ]decyl group, 3-ethyloxetanyl group, and the like.

[0042] X 2 Examples of the divalent linking group include alkanediyl groups such as methylene, ethylene, and 1,3-propanediyl; and divalent groups in which any methylene group in an alkanediyl group having 2 to 10 carbon atoms is replaced with an oxygen atom.

[0043] Specific examples of the monomer that provides the third structural unit 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)methyl (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.

[0044] When the polymer (A) contains the third structural unit, the content of the third structural unit in the polymer (A) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, based on all structural units constituting the polymer (A), in order to sufficiently suppress melting of the film during the heating step (post-baking) during film formation. Furthermore, from the viewpoint of ensuring the content ratios of the first structural unit and the second structural unit in the polymer (A), the content of the third structural unit is preferably 75% by mass or less, more preferably 65% by mass or less, and even more preferably 60% by mass or less, based on all structural units constituting the polymer (A).

[0045] The polymer (A) preferably contains a structural unit having an alicyclic epoxy group as the third structural unit. By containing a structural unit having an alicyclic epoxy group in the polymer (A), the dielectric constant of the film can be reduced while the melt resistance of the film formed from the composition can be further improved. Here, the "alicyclic epoxy group" refers to a group formed by bonding two adjacent carbon atoms constituting an alicyclic ring to the same oxygen atom, and examples thereof include a 3,4-epoxycyclohexyl group, a 3,4-epoxytricyclo[5.2.1.0] group, and a 5,4-epoxytricyclo[5.2.1.0] group. 2,6 ]decyl group and the like.

[0046] The content of the structural units having an alicyclic epoxy group in the polymer (A) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 5% by mass or more, based on all structural units constituting the polymer (A). The content of the structural units having an alicyclic epoxy group is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less, based on all structural units constituting the polymer (A).

[0047] Specific examples of monomers that provide other structural units contained in the polymer (A) include, in addition to the above, (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, unsaturated dicarboxylic acid dialkyl ester compounds, and silyl group-containing vinyl compounds.

[0048] Specific examples of these 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] (meth)acrylate, and the like. 2,6 ] decan-8-yl, (meth)acrylic acid tricyclo[5.2.1.0 2,5 ] decan-8-yloxyethyl, isobornyl (meth)acrylate, etc.; Examples of (meth)acrylic acid esters having an aromatic ring structure include phenyl (meth)acrylate and benzyl (meth)acrylate; 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, vinylpyridine, etc.; 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, (meth)acrylic acid glycerin carbonate, (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; As the unsaturated dicarboxylic acid dialkyl ester compound, diethyl itaconate, etc.; Silyl group-containing vinyl compounds include styryltrimethoxysilane, styryltriethoxysilane, styrylmethyldimethoxysilane, styrylethyldiethoxysilane, styryldimethoxyhydroxysilane, styryldiethoxyhydroxysilane, 4-vinylphenyltrimethoxysilane, (meth)acryloxyphenyltrimethoxysilane, (meth)acryloxyphenyltriethoxysilane, (meth)acryloxyphenylmethoxydimethoxysilane, (meth)acryloxyphenylethyldiethoxysilane, and trimethoxy(4-vinylnaphthyl)silane. Examples of suitable monomers that provide other structural units include silane, triethoxy(4-vinylnaphthyl)silane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 4-(meth)acryloxybutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-isopropenylphenyloxytrimethylsilane, 4-isopropenylphenyloxytriethylsilane, etc. In addition to the above, examples of suitable monomers that provide other structural units include vinyl chloride, vinylidene chloride, vinyl acetate, etc.

[0049] When the polymer (A) contains a structural unit having a hydrocarbon ring as another structural unit (excluding the first to third structural units, this is also referred to as a "fourth structural unit"), it is preferable in that melting of the film can be sufficiently suppressed even when heating (post-baking) is performed at a relatively high temperature during film formation. The hydrocarbon ring may be an alicyclic ring or an aromatic ring. Examples of the alicyclic ring include a cyclopentane ring, a cyclohexane ring, a cyclohexene ring, a norbornane ring, an adamantane ring, a tricyclo[5.2.1.0] ring, a cyclopentane ring, a cyclohexane ring, a cyclohexene ring, a norbornane ring, a cyclohexene ... 2,5 ] decane ring, etc. Examples of aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. Specific examples of the fourth structural unit include structural units derived from a monomer having a hydrocarbon ring, among the above-mentioned examples of monomers that provide other structural units.

[0050] When the polymer (A) contains the fourth structural unit, the content of the fourth structural unit is preferably 1% by mass or more, more preferably 2% by mass or more, based on all structural units constituting the polymer (A), and is preferably 50% by mass or less, more preferably 45% by mass or less, based on all structural units constituting the polymer (A).

[0051] Production of polymer (A) The polymer (A) can be produced, for example, by a known method such as radical polymerization using a monomer capable of introducing each of the structural units described above in an appropriate solvent in the presence of a polymerization initiator. Examples of the polymerization initiator include azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(isobutyrate) dimethyl. The proportion of the polymerization initiator used is preferably 0.01 to 30 parts by mass per 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.

[0052] In synthesizing polymer (A), the amount of each monomer used can be appropriately set so that the content ratio of the structural units derived from each monomer falls within the above-mentioned preferred range. For example, the amount of the monomer that provides the first structural unit used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the total amount of monomers used in synthesizing polymer (A). Furthermore, the amount of the monomer that provides the first structural unit used is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the total amount of monomers used in synthesizing polymer (A).

[0053] The amount of the monomer that provides the second structural unit used is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of the total amount of the monomers used to synthesize the polymer (A). The amount of the monomer that provides the second structural unit used is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of the monomers used to synthesize the polymer (A).

[0054] The amount of the monomer that provides the third structural unit used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more, relative to 100 parts by mass of the total amount of the monomers used in the synthesis of polymer (A). The amount of the monomer that provides the third structural unit used is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less, relative to 100 parts by mass of the total amount of the monomers used in the synthesis of polymer (A).

[0055] In the polymerization, the reaction temperature is usually 30°C to 180°C. The reaction time varies depending on the types 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 preparing the photosensitive composition as it is dissolved in the reaction solution, or may be used for preparing the photosensitive 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.

[0056] The weight average molecular weight (Mw) of the polymer (A) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 2,000 or more. An Mw of 2,000 or more is preferred in that a cured film having sufficiently high heat resistance and chemical resistance and exhibiting good developability can be obtained. The Mw of the polymer (A) is more preferably 5,000 or more, even more preferably 6,000 or more, and particularly preferably 7,000 or more. Furthermore, from the viewpoint of improving film-forming properties, the Mw of the polymer (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.

[0057] The molecular weight distribution (Mw / Mn) of the polymer (A), which is expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in terms of polystyrene measured by GPC, is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.5 or less.

[0058] The present composition may contain polymer (A) alone as a polymer component, or may further contain a polymer different from polymer (A) (hereinafter also referred to as "other polymer"). As the other polymer, an addition polymer not having the first structural unit can be preferably used. Examples of monomers constituting the other polymer include compounds similar to the monomers that provide the second structural unit, the third structural unit, or other structural units exemplified in the description of polymer (A).

[0059] The content of polymer (A) in the composition is 25% by mass or more, based on the total amount of polymer components contained in the composition. If the content of polymer (A) is less than 25% by mass, the cured film obtained using the composition will not be able to achieve a sufficient effect of improving the bending resistance and reworkability in a balanced manner. From this perspective, the content of polymer (A) is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, and particularly preferably 60% by mass or more, based on the total amount of polymer components contained in the composition.

[0060] <Quinone diazide compounds> The quinone diazide compound is a radiation-sensitive acid generator that generates a carboxylic acid upon irradiation with radiation. As the quinone diazide compound, a condensation product of a phenolic compound or an alcoholic compound (hereinafter also referred to as a "mother nucleus") with 1,2-naphthoquinone diazide sulfonic acid halide is preferably used.

[0061] Examples of the mother nucleus include trihydroxybenzophenone, tetrahydroxybenzophenone, pentahydroxybenzophenone, hexahydroxybenzophenone, (polyhydroxyphenyl)alkane, and other mother nuclei.Specific examples of these include trihydroxybenzophenones such as 2,3,4-trihydroxybenzophenone and 2,4,6-trihydroxybenzophenone; tetrahydroxybenzophenones such as 2,2',4,4'-tetrahydroxybenzophenone, 2,3,4,3'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,2'-tetrahydroxy-4'-methylbenzophenone and 2,3,4,4'-tetrahydroxy-3'-methoxybenzophenone; pentahydroxybenzophenones such as 2,3,4,2',6'-pentahydroxybenzophenone; and hexahydroxybenzophenones such as 2,4,6,3',4',5'-hexahydroxybenzophenone. , 3,4,5,3',4',5'-hexahydroxybenzophenone, etc.; (polyhydroxyphenyl)alkanes such as bis(2,4-dihydroxyphenyl)methane, bis(p-hydroxyphenyl)methane, tri(p-hydroxyphenyl)methane, 1,1,1-tri(p-hydroxyphenyl)ethane, bis(2,3,4-trihydroxyphenyl)methane, 2,2-bis(2,3,4-trihydroxyphenyl)propane, 1,1,3-tris(2,5-dimethyl-4-hydroxyphenyl)-3-phenylpropane, 4,4'-[1-[4-[1-[4-hydroxyphenyl]-1-methylethyl]phenyl]ethylidene]bisphenol, bis(2,5-dimethyl-4-hydroxyphenyl)-2-hydroxyphenylmethane, 3,3,3',3'- Examples of the mother nucleus include tetramethyl-1,1'-spirobiindene-5,6,7,5',6',7'-hexanol and 2,2,4-trimethyl-7,2',4'-trihydroxyflavan; and other mother nuclei include 2-methyl-2-(2,4-dihydroxyphenyl)-4-(4-hydroxyphenyl)-7-hydroxychroman and 2-[bis{(5-isopropyl-4-hydroxy-2-methyl)phenyl}methyl].

[0062] Of these, 2,3,4,4'-tetrahydroxybenzophenone, 1,1,1-tri(p-hydroxyphenyl)methane, 1,1,1-tri(p-hydroxyphenyl)ethane, and 4,4'-[1-[4-[1-[4-hydroxyphenyl]-1-methylethyl]phenyl]ethylidene]bisphenol are preferred as the mother nucleus.

[0063] The 1,2-naphthoquinone diazide sulfonic acid halide is preferably 1,2-naphthoquinone diazide sulfonic acid chloride. Specific examples include 1,2-naphthoquinone diazide-4-sulfonic acid chloride and 1,2-naphthoquinone diazide-5-sulfonic acid chloride. Of these, 1,2-naphthoquinone diazide-5-sulfonic acid chloride is preferably used as the 1,2-naphthoquinone diazide sulfonic acid halide.

[0064] In the condensation reaction to obtain the above condensation product, the ratio of the mother nucleus to the 1,2-naphthoquinone diazide sulfonic acid halide is preferably 30 to 85 mol %, more preferably 50 to 70 mol %, based on the number of OH groups in the mother nucleus. The above condensation reaction can be carried out according to a known method. A 1,2-quinone diazide compound is obtained by the condensation reaction of the mother nucleus with the 1,2-naphthoquinone diazide sulfonic acid halide.

[0065] In the present composition, the content of the quinone diazide compound is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the polymer component contained in the composition. Furthermore, the content of the quinone diazide compound is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of the polymer component. When the content of the quinone diazide compound is 2 parts by mass or more, sufficient acid is generated upon irradiation of the present composition, thereby sufficiently increasing the difference in solubility between the irradiated and unirradiated portions in an alkaline solution. This allows for good patterning. Furthermore, the amount of acid involved in the reaction with the polymer component can be increased, thereby ensuring sufficient heat resistance and chemical resistance. On the other hand, when the content of the quinone diazide compound is 100 parts by mass or less, the amount of unreacted quinone diazide compound can be sufficiently reduced, thereby preventing a decrease in developability due to residual quinone diazide compound.

[0066] <Other ingredients> The composition may further contain, in addition to the polymer component and the quinone diazide compound, components other than the polymer component and the quinone diazide compound (hereinafter also referred to as "other components"). Examples of other components include a thermal crosslinking agent, a thermal acid generator, an adhesion aid, and a solvent.

[0067] (thermal crosslinking agent) The thermal crosslinking agent is not particularly limited as long as it is a compound having a functional group (hereinafter also referred to as a "crosslinkable group") that can react with a reactive site of the polymer (A) upon heating (for example, an ortho- or para-position relative to a hydroxyl group of a phenol structure, a carboxyl group, an alcoholic hydroxyl group, an amino group, etc.). Examples of the crosslinkable group include an isocyanate group, a protected isocyanate group, a cyclocarbonate group, a methylol group, a protected methylol group, an alkoxymethyl group, a group having a ketene structure, and a group having a Meldrum's acid structure. The number of crosslinkable groups in the thermal crosslinking agent is preferably 2 to 10, and more preferably 2 to 6.

[0068] As a thermal crosslinking agent, "-CH2-OR 4 " (wherein R 4 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally detachable group.) (hereinafter, also referred to as "methylol-based crosslinking agent") can be preferably used. 4 In the formula (I), examples of the thermally detachable group include a tert-butyl group, a benzyl group, an acetyl group, a methoxymethyl group, a 2-tetrahydropyranyl group, and a 2-tetrahydrofuranyl group.

[0069] Specific examples of methylol-based crosslinking agents include 2,2-bis(4-hydroxymethylphenyl)propane, 2,2-bis(2,3,4-trihydroxymethylphenyl)propane, and compounds represented by the following formulas (me-1) to (me-11). [ka]

[0070] The molecular weight of the thermal crosslinking agent is preferably at least 80, more preferably at least 100, and even more preferably at least 150. The molecular weight of the thermal crosslinking agent is preferably at most 500, more preferably at most 450, and even more preferably at most 400. When the molecular weight of the thermal crosslinking agent is within the above range, it is possible to increase the melt resistance of the film while suppressing a decrease in the sensitivity and development solubility of the composition, and it is also preferable in that a low dielectric constant can be achieved.

[0071] The content of the thermal crosslinking agent in the composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the polymer component contained in the composition. The content of the thermal crosslinking agent is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, per 100 parts by mass of the polymer component. When the content of the thermal crosslinking agent is 0.5 parts by mass or more, the effect of improving the melt resistance of the film obtained from the composition can be sufficiently obtained. When the content of the thermal crosslinking agent is 30 parts by mass or less, the residue caused by unreacted thermal crosslinking agent can be sufficiently reduced.

[0072] (thermal acid generator) A thermal acid generator is a component that generates an acid upon heating. In particular, when a methylol-based crosslinking agent is used as the thermal crosslinking agent, the acid generated from the thermal acid generator upon heating can promote the crosslinking reaction of the methylol-based crosslinking agent. This can enhance the effect of suppressing film melting due to heating (post-baking) during cured film formation.

[0073] As the thermal acid generator, compounds known as the thermal acid generator to be blended in the polymer composition for forming a cured film can be appropriately used.Specific examples of the thermal acid generator include 4-hydroxyphenyl dimethyl sulfonium trifluoromethanesulfonate, benzyl-4-hydroxyphenyl methyl sulfonium trifluoromethanesulfonate, benzyl-4-hydroxyphenyl methyl sulfonium hexafluorophosphate, 2-methylbenzyl-4-hydroxyphenyl methyl sulfonium trifluoromethanesulfonate, 4-acetoxyphenyl dimethyl sulfonium trifluoromethanesulfonate, 4-acetoxyphenyl benzyl methyl sulfonium trifluoromethanesulfonate, 4-(methoxycarbonyloxy)phenyl dimethyl sulfonium trifluoromethanesulfonate, benzyl-4-(methoxycarbonyloxy)phenyl methyl sulfonium trifluoromethanesulfonate, benzyl-4-(methoxycarbonyloxy)phenyl methyl sulfonium hexafluorophosphate, etc.

[0074] The content of the thermal acid generator in the composition is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the polymer component contained in the composition, from the viewpoint of suppressing melting of the film during heating (post-baking) and obtaining a pattern of the desired shape. Also, from the viewpoint of suppressing the generation of residues, the content of the thermal acid generator is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the polymer component contained in the composition.

[0075] (adhesion aid) The adhesion aid is a component that improves the adhesion between the cured film formed using the present composition and the substrate. A functional silane coupling agent having a reactive functional group can be preferably used as the adhesion aid. Examples of the reactive functional group possessed by the functional silane coupling agent include a carboxy group, a (meth)acryloyl group, an oxiranyl group, an oxetanyl group, a vinyl group, an isocyanate group, and an amino group.

[0076] 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, 3-isocyanatopropyltriethoxysilane, N-2-(aminopropyltriethoxysilane), Examples thereof include N-(2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-methyl-3-(trimethoxysilyl)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane.

[0077] The content of the adhesion aid in the present 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.

[0078] (solvent) The present composition is a liquid composition in which the polymer component, the quinone diazide compound, and other optional components are dissolved or dispersed in a solvent, preferably an organic solvent that dissolves each of the components in the present composition but does not react with each of the components.

[0079] Specific examples of the solvent 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 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.

[0080] In addition to the above, other components include, for example, antioxidants, acid diffusion controllers, orthoester compounds, polyfunctional polymerizable compounds (polyfunctional (meth)acrylates, etc.), surfactants (fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, etc.), polymerization inhibitors, chain transfer agents, etc. The blending ratio of these components can be appropriately selected depending on each component within a range that does not impair the effects of the present disclosure.

[0081] The solids concentration of the present composition (the ratio of the total mass of components other than the solvent in the photosensitive composition to the total mass of the photosensitive composition) is appropriately selected taking into consideration viscosity, volatility, and the like. The solids concentration of the present composition is preferably in the range of 5 to 60 mass %. A solids concentration of 5 mass % or more ensures a sufficient coating thickness when the present composition is applied to a substrate. On the other hand, a solids concentration of 60 mass % or less prevents the coating thickness from becoming too large, and further allows the viscosity of the photosensitive composition to be appropriately increased, ensuring good coatability. The solids concentration of the present composition is more preferably 10 to 55 mass %, and even more preferably 12 to 50 mass %.

[0082] <<Cured film and manufacturing method thereof>> The cured film of the present invention is formed from the photosensitive composition prepared as described above. The photosensitive composition has high sensitivity and can form a cured film that is excellent in bending resistance, reworkability, and heat resistance. The photosensitive composition of the present invention is suitable for forming a planarizing film, an interlayer insulating film, or a bank material (also called a partition wall), and is particularly suitable for use in organic EL devices. Among these, the composition is particularly suitable as a material for forming a planarizing film for organic EL devices.

[0083] In producing a cured film, a positive cured film can be formed by using the photosensitive composition of the present invention. The cured film can be produced using the composition by a method including, for example, the following steps 1 to 4. Step 1: Step of forming a coating film using the photosensitive composition of the present invention (film formation step) Step 2: A step of exposing at least a part of the coating film formed in the film-forming step (exposure step) Step 3: A step of developing the coating film after exposure in the exposure step (development step) Step 4: Heating the coating film developed in the development step (heating step) Each step will be described in detail below.

[0084] [Process 1: Coating process] In step 1, the 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 removed, preferably 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 a planarizing film using the composition, the composition is applied to a substrate on which switching elements such as TFTs are provided, to form a coating film. Examples of substrates that can be used include glass substrates, silicon substrates, and resin substrates. The surface of the substrate on which the coating film is to be formed may have a metal thin film formed thereon depending on the application, or may have been subjected to various surface treatments such as HMDS (hexamethyldisilazane) treatment.

[0085] Examples of methods for applying the composition include spraying, roll coating, spin coating, slit die coating, bar coating, and inkjet coating. Of these, spin coating, slit die coating, and bar coating are preferred. Prebaking conditions vary depending on the type and content of each component in the composition, but are, for example, 60 to 120°C for 0.5 to 10 minutes. The thickness of the coating film formed (i.e., the film thickness after prebaking) is preferably 0.1 to 12 μm. The composition applied to the surface to be coated may be subjected to reduced pressure drying (VCD) before prebaking.

[0086] [Step 2: Exposure step] In step 2, at least a portion of the coating film formed in step 1 is irradiated with radiation. At this time, the coating film is irradiated with radiation 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 light, far ultraviolet light, visible light, X-rays, and electron beams. Among these, ultraviolet light is preferred, and examples thereof include g-rays (wavelength 436 nm) and i-rays (wavelength 365 nm). The radiation exposure dose is 0.1 to 20,000 J / m 2 is preferred.

[0087] [Process 3: Development process] In step 3, the coating film irradiated in step 2 is developed. Specifically, the coating film irradiated in step 2 is developed using a developer to remove the irradiated portions, resulting in positive development. Examples of the developer include an aqueous solution of an alkali (basic compound). Examples of alkali include sodium hydroxide, tetramethylammonium hydroxide, and the alkalis exemplified in paragraph

[0127] of JP 2016-145913 A. The alkali concentration in the aqueous alkali solution is preferably 0.1 to 5% by mass to obtain adequate developability. Examples of development methods include a puddle method, a dipping method, a swinging 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, the patterned coating film is preferably rinsed with running water.

[0088] [Process 4: Heating process] 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, 150 to 260°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. This heating treatment causes a curing reaction to proceed, and a cured product having the desired pattern can be formed on the substrate. The shape of the pattern of the cured film is not particularly limited, and examples include a line-and-space pattern, a dot pattern, a hole pattern, and a lattice pattern.

[0089] When producing a cured film, in addition to the above steps 1 to 4, the following post-development exposure step, pre-heating step, or both may be further included. Post-development exposure step: a step of exposing the coating film after development in the development step of step 3 and before heating in the heating step of step 4 Pre-heating step: A step of heating the coating film at a temperature lower than the heating temperature in the heating step of step 4 after development in the developing step of step 3 and before heating in the heating step of step 4.

[0090] [Post-development exposure process] When producing a cured film using this composition, it is preferable to expose the coating film after development in the development step and before heating in the heating step. By providing such a step (post-development exposure step), the naphthoquinone diazide compound can be faded and the transmittance of the coating film can be improved. It is preferable that the exposure in the post-development exposure step is carried out over the entire substrate surface. Specific examples and preferred examples of the type of radiation and exposure dose can be applied to the explanation for the exposure step in step 2. For example, an exposure dose of 500 to 5,000 J / m 2 The entire substrate surface is exposed to a mixture of ghi lines.

[0091] [Preheating process] When producing a cured film using the present composition, it is preferable to heat the coating film at a temperature lower than the heating temperature in the heating step after development in the development step of step 3 and before heating in the heating step of step 4. By providing a preheating step, it is possible to prevent the coating film from melting and the pattern from collapsing due to heating at a relatively high temperature in the heating step of step 4. When a post-development exposure step is provided, it is preferable to carry out the preheating step after exposure in the post-development exposure step and before heating in the heating step of step 4.

[0092] The heating in the preheating step (hereinafter also referred to as "middle bake") may be carried out after the exposure step and before the development step. Alternatively, the middle bake may be carried out after the development step and before the heating step. Of these, it is preferable to carry out the middle bake after the exposure step and before the development step, since this allows for good patterning by suppressing development residues and melting of the coating film.

[0093] The middle bake can be performed using a heating device such as an oven or a hot plate. Regarding the middle bake conditions, the heating temperature is preferably higher than that of the pre-bake and lower than that of the post-bake, for example, 110 to 180° C. The heating time is, for example, 1 to 20 minutes when the heat treatment is performed on a hot plate, and 3 to 40 minutes when the heat treatment is performed in an oven.

[0094] <Display device> The display device of the present invention includes a cured film formed using the present composition. By forming a cured film using the present composition, a cured film exhibiting excellent bending resistance can be obtained. Therefore, the present composition is particularly suitable as a planarizing film-forming composition for organic EL devices, i.e., a planarizing film-forming composition for forming an insulating layer that covers steps in TFT circuits and wiring formed on a substrate. Examples of display devices include liquid crystal display devices and organic EL display devices.

[0095] Cured films formed using the present composition have excellent heat resistance and bending resistance, making them suitable as components for flexible displays. Flexible displays include foldable displays that can be folded, bendable displays that can be folded back or bent, and rollable displays that can be wound up. Furthermore, in response to narrower picture frames, structures are sometimes adopted in which lead wiring is bent to the back surface of the image display unit, and cured films formed using the present composition can also be applied to structures that have bent portions.

[0096] According to the present disclosure described above in detail, the following means are provided. <Means 1> A photosensitive composition containing a polymer component and a quinone diazide compound, wherein the polymer component includes a polymer (A) having a first structural unit and a second structural unit, the first structural unit having a cyclic ether structure and a methylene group bonded to a carbon atom constituting the cyclic ether structure in its main chain, and the second structural unit is at least one selected from the group consisting of structural units derived from maleimide and structural units having an acid group, and the photosensitive composition contains the polymer (A) in an amount of 25 mass% or more based on the total amount of the polymer component. <Means 2> The photosensitive composition according to <Means 1>, wherein the first structural unit is represented by the above formula (1). <Means 3> The photosensitive composition according to <Means 1> or <Means 2>, wherein the second structural unit 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. <Means 4> The photosensitive composition according to <Means 3>, wherein the polymer (A) has, as the second structural unit, at least one selected from the group consisting of a structural unit derived from maleimide, a structural unit having a carboxy group, and a structural unit having a sulfonic acid group. <Measure 5> The photosensitive composition according to <Measure 3> or <Measure 4>, wherein the polymer (A) has a structural unit having a phenolic hydroxyl group as the second structural unit. <Measure 6> The photosensitive composition according to any one of <Measures 1> to <Measure 5>, wherein the polymer (A) further has a third structural unit having an oxiranyl group or an oxetanyl group. <Means 7> The photosensitive composition according to <Means 6>, wherein the polymer (A) contains a structural unit having an alicyclic epoxy group as the third structural unit. <Measure 8> The photosensitive composition according to any one of <Measures 1> to <Measure 7>, further comprising a thermal crosslinking agent. <Means 9> The thermal crosslinking agent is -CH2-OR 4 (However, R 4 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally cleavable group. <Means 10> The photosensitive composition according to any one of <Means 1> to <Means 9>, further comprising a thermal acid generator. <Means 11> The photosensitive composition according to any one of <Means 1> to <Means 10>, which is used for forming a planarizing film, an interlayer insulating film, or a bank material. <Means 12> The photosensitive composition according to <Means 11>, which is for use in an organic EL device. <Means 13> A cured film formed from the photosensitive composition according to any one of <Means 1> to <Means 10>. <Means 14> The cured film according to <Means 13>, which is a planarizing film, an interlayer insulating film, or a bank material. <Means 15> A method for producing a photosensitive film by using the photosensitive composition according to any one of <Means 1> to <Means 10>, a film-forming step of forming a photosensitive film by exposing at least a part of the photosensitive film formed by the film-forming step, a development step of developing the photosensitive film after exposure by the exposure step, and a heating step of heating the photosensitive film developed by the development step, A method for producing a cured film, comprising: <Means 16> The method for producing a cured film according to <Means 15>, further comprising a step of exposing the coating film after development in the developing step and before heating in the heating step. <Means 17> The method for producing a cured film according to <Means 15> or <Means 16>, further comprising a step of heating the coating film after development in the developing step but before heating in the heating step at a temperature lower than the heating temperature in the heating step. <Means 18> A display device comprising the cured film according to <Means 13> or <Means 14>. [Example]

[0097] The present invention will be described in more 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 by mass unless otherwise specified.

[0098] [Weight average molecular weight (Mw) and number average molecular weight (Mn)] The weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured by the following method. Measurement method: Gel permeation chromatography (GPC) method Equipment: Showa Denko GPC-101 GPC column: Shimadzu GLC GPC-KF-801, GPC-KF-802, GPC-KF-803 and GPC-KF-804 Mobile phase: Tetrahydrofuran Column temperature: 40℃ ·Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0099] [Monomer] The abbreviations of the monomers used in the synthesis of the polymers are as follows: <Monomer that provides the first structural unit> AOMA: 2-(allyloxymethyl) methyl acrylate <<Monomer that provides the second structural unit>> MI: Maleimide MA: methacrylic acid 4IPP: 4-isopropenylphenol HPMA: 4-hydroxyphenyl methacrylate <Monomer that provides the third structural unit> ECHMA: 3,4-epoxycyclohexylmethyl methacrylate GMA: Glycidyl methacrylate OXMA: (3-ethyloxetan-3-yl)methyl methacrylate

[0100] <<Monomer that provides the fourth structural unit>> MMA: methyl methacrylate ST: styrene CHMI: N-cyclohexylmaleimide PMI: N-phenylmaleimide <Monomers that provide other structural units> DOXA: (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate MPTES: 3-methacryloxypropyltriethoxysilane

[0101] <Synthesis of Polymer (A)> [Synthesis Example 1] Synthesis of polymer (A-1) A flask equipped with a condenser and a stirrer was charged with 10 parts of 2,2'-azobis(isobutyrate)dimethyl and 200 parts of diethylene glycol methyl ethyl ether. Subsequently, 10 parts of methyl 2-(allyloxymethyl)acrylate, 10 parts of maleimide, 50 parts of 3,4-epoxycyclohexylmethyl methacrylate, 10 parts of 4-isopropenylphenol, and 20 parts of methyl methacrylate were charged. After nitrogen substitution, the temperature of the solution was raised to 80°C with gentle stirring and maintained at this temperature for 5 hours, yielding a polymer solution containing polymer (A-1). The solids concentration of this polymer solution was adjusted to 35% by mass. The Mw of polymer (A-1) was 10,000, and the molecular weight distribution (Mw / Mn) was 2.2.

[0102] [Synthesis Examples 2 to 13, Comparative Synthesis Examples 2 to 4] Synthesis of polymers (A-2) to (A-13) and (CA-2) to (CA-4) 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.

[0103] [Table 1]

[0104] [Comparative Synthesis Example 1] Synthesis of polymer (CA-1) Under a dry nitrogen stream, 30 parts by weight of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved in 500 g of N-methyl-2-pyrrolidone (NMP), to which 26.7 parts by weight of 3,3',4,4'-oxydiphthalic dianhydride and 0.9 parts by weight of 4-aminophenol were added, and the mixture was allowed to react at 40°C for 6 hours. Next, NMP was added to the resulting polyamic acid solution, and pyridine and acetic anhydride were added in amounts of 1.8 molar equivalents relative to the carboxyl groups derived from the tetracarboxylic dianhydride of the polyamic acid. A dehydration ring-closing reaction was carried out at 100°C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP and further concentrated. The resulting polymer solution was then poured into a large excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and dried under vacuum at 80°C to obtain a polyimide (referred to as "Polymer (CA-1)").

[0105] <Preparation of Photosensitive Composition> The components used in preparing the photosensitive composition are listed below. <Polymer component> A-1 to A-13: Polymers (A-1) to (A-13) synthesized in Synthesis Examples 1 to 13 CA-1 to CA-4: Polymers (CA-1) to (CA-4) synthesized in Comparative Synthesis Examples 1 to 4

[0106] <Quinone diazide compounds> B-1: Condensation product of 4,4'-[1-[4-[1-[4-hydroxyphenyl]-1-methylethyl]phenyl]ethylidene]bisphenol (1.0 mol) and 1,2-naphthoquinonediazide-5-sulfonic acid chloride (2.0 mol) B-2: Condensation product of 1,1,1-tri(p-hydroxyphenyl)ethane (1.0 mol) and 1,2-naphthoquinonediazide-5-sulfonic acid chloride (2.0 mol)

[0107] <Thermal crosslinking agent> C-1: 4,4'-[1-[4-[1-[4-hydroxy-3,5-bis(methoxymethyl)phenyl]-1-methylethyl]phenyl]ethylidene]-bis[2,6-bis(methoxymethyl)phenol] C-2: 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate

[0108] <<Thermal Acid Generator>> D-1: Benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate

[0109] [Example 1] To the polymer solution containing the polymer (A-1) obtained in Synthesis Example 1, 20 parts of a quinone diazide compound (B-1), 10 parts of a thermal crosslinking agent (C-1), and 1 part of a thermal acid generator (D-1) were mixed in an amount corresponding to 100 parts (solids) of the polymer (A-1), and diethylene glycol ethyl methyl ether, propylene glycol methyl ether acetate, and propylene glycol monomethyl ether were added in a mass ratio of 3:4:3 so that the final solids concentration was 20% by mass. The mixture was then filtered through a membrane filter with a pore size of 0.2 μm to prepare a photosensitive composition (S-1).

[0110] [Examples 2 to 17, Comparative Examples 1 to 4] Photosensitive compositions of Examples 2 to 17 and Comparative Examples 1 to 4 were prepared in the same manner as in Example 1, except that the types and amounts (parts by mass) of each component shown in Table 2 were used.

[0111] [Table 2]

[0112] <Evaluation> The photosensitive compositions of Examples 1 to 17 and Comparative Examples 1 to 4 were evaluated for the following items by the methods described below. The evaluation results are shown in Table 3.

[0113] [sensitivity] Using a spinner, a photosensitive composition was applied to a silicon substrate treated with HMDS at 60°C for 60 seconds, followed by pre-baking on a hot plate at 100°C for 2 minutes to form a coating film with an average thickness of 3.0 μm. This coating film was then irradiated with a predetermined amount of ultraviolet light from a mercury lamp through a pattern mask with a 10 μm-wide line-and-space pattern. The coating was then developed at 25°C for 60 seconds using a 2.38% by weight aqueous solution of tetramethylammonium hydroxide as the developer, followed by rinsing with running ultrapure water for 1 minute. The minimum exposure dose required to form a 10 μm-wide line-and-space pattern was measured, and radiation sensitivity was evaluated based on this minimum exposure dose.

[0114] [Bending resistance] Photosensitive composition R-1 was applied to a polyimide film substrate using a spin coater, and the solvent was removed from the photosensitive composition R-1 on the substrate under vacuum with an ultimate pressure set to 100 Pa. The substrate was then prebaked at 100°C for 2 minutes to form a coating film. The coating film was then developed using a developer (a 2.38% by mass aqueous solution of tetramethylammonium hydroxide) at 25°C for 60 seconds, and then washed with running ultrapure water for 1 minute. The resulting coating film was exposed to 3000 J / m irradiation using a proximity exposure machine (Canon's "MA-1200" (ghi-ray mixed)). 2 After irradiating the entire surface of the substrate with light, the substrate was heated at 250° C. for 1 hour in a clean oven substituted with nitrogen, thereby forming a cured film having an average film thickness of 3.0 μm on the substrate. The resulting substrate with the cured film was cut into a size of 50 mm length x 50 mm width. Next, the substrate with the cured film was folded with the surface on which the cured film was formed facing outward so that the polyimide film substrates were in contact with each other, and held in this state for 10 minutes. 10 minutes after bending, the folded substrate with the cured film was opened, and the folded portion of the cured film surface was observed using an optical microscope. The bending resistance (bending resistance) was evaluated based on changes in appearance. The evaluation criteria were as follows: no cracks in the cured film were rated "good (○)", partial cracks in the cured film were rated "fair (△)", and cracks throughout the entire cured film were rated "poor (×)".

[0115] [Heat resistance] The photosensitive composition R-1 was applied onto a silicon substrate using a spinner, and then prebaked on a hot plate at 100°C for 2 minutes to form a coating film with a thickness of 3.0 µm. Next, a proximity exposure machine (Canon "MA-1200" (ghi-ray mixed)) was used to apply 3000 J / m 2 After irradiating the entire substrate with light, the silicon substrate was heated at 250°C for 60 minutes in a clean oven purged with nitrogen to form a cured film. The 1% thermal weight loss temperature of the cured film was measured in air using a simultaneous differential thermal and thermogravimetric analyzer (Hitachi High-Tech Science Corporation, TG / DTA220U). Heat resistance was evaluated as follows: a 5% weight loss temperature of 320°C or higher was rated as "excellent (◎)," a temperature of 300°C or higher but less than 320°C was rated as "good (○)," a temperature of 280°C or higher but less than 300°C was rated as "fair (△)," and a temperature of less than 280°C was rated as "poor (×)."

[0116] [Reworkability] Using a spinner, the photosensitive composition was applied to a silicon substrate that had been treated with HMDS at 60°C for 60 seconds, and then prebaked on a hot plate at 100°C for 2 minutes to form a coating film with an average thickness of 3.0 μm. The substrate was then immersed in propylene glycol monomethyl ether acetate at 23°C, and the presence or absence of coating film remaining on the substrate was observed. If the immersion time was less than 2 minutes, when no coating film remained, it was evaluated as "excellent (◎)", if it was 2 to 3 minutes, it was evaluated as "good (◯)", and if it was 5 minutes or more, it was evaluated as "unacceptable (X)".

[0117] [Resistance to melting during post-bake] Using a spinner, a photosensitive composition was applied to a silicon substrate that had been treated with HMDS at 60°C for 60 seconds, and then prebaked on a hot plate at 100°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 with a 10 μm-wide line-and-space pattern. Next, a development process was carried out at 25°C for 60 seconds using a 2.38% by mass aqueous solution of tetramethylammonium hydroxide as the developer, followed by rinsing with running ultrapure water for 1 minute. The line width of the resulting line-and-space pattern was designated X1. Next, a proximity exposure machine (Canon's "MA-1200" (ghi-ray mixed)) was used to expose the film at 3000 J / m 2 After irradiating the entire substrate surface with light, the silicon substrate was heated in a clean oven at 140°C for 15 minutes. The silicon substrate was then heated at 230°C for 30 minutes to form a cured film. The line width of the resulting line and space pattern was designated X2. When the value obtained by subtracting X2 from X1 (=X1-X2) was less than 0.1 μm, the result was rated as "excellent (◎)," when it was 0.1 μm or greater but less than 0.2 μm, the result was rated as "good (○)," and when it was 0.2 μm or greater, the result was rated as "unacceptable (×)."

[0118] [Table 3]

[0119] As shown in Table 3, the photosensitive compositions of Examples 1 to 17 were evaluated as having good practical properties, such as radiation sensitivity, bending resistance, heat resistance, reworkability, and resistance to melting during post-baking, and the various properties were well-balanced. In contrast, the cured film formed using the photosensitive composition of Comparative Example 1 was poor in reworkability. Furthermore, the cured films formed using the photosensitive compositions of Comparative Examples 2 to 4 were poorer than those of Examples 1 to 17 in bending resistance and heat resistance.

Claims

1. A photosensitive composition containing a polymer component and a quinone diazide compound, the polymer component includes a polymer (A) having a first structural unit and a second structural unit, the first structural unit has, in a main chain, a cyclic ether structure and a methylene group bonded to a carbon atom constituting the cyclic ether structure; the second structural unit is at least one selected from the group consisting of a structural unit derived from maleimide and a structural unit having an acid group, A photosensitive composition comprising the polymer (A) in an amount of 25 mass % or more based on the total amount of the polymer components.

2. The photosensitive composition according to claim 1 , wherein the first structural unit is represented by the following formula (1): 【Chemical 1】 (In formula (1), R １ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms. ２ is a hydrogen atom or -COOR ３ It is. ３ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms. n is 0 or 1.

3. 2. The photosensitive composition according to claim 1, wherein the second structural unit 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.

4. 4. The photosensitive composition according to claim 3, wherein the polymer (A) has, as the second structural unit, at least one selected from the group consisting of a structural unit derived from maleimide, a structural unit having a carboxy group, and a structural unit having a sulfonic acid group.

5. The photosensitive composition according to claim 3 , wherein the polymer (A) has a structural unit having a phenolic hydroxyl group as the second structural unit.

6. The photosensitive composition according to claim 1 , wherein the polymer (A) further comprises a third structural unit having an oxiranyl group or an oxetanyl group.

7. The photosensitive composition according to claim 6 , wherein the polymer (A) has, as the third structural unit, a structural unit having an alicyclic epoxy group.

8. The photosensitive composition of claim 1 further comprising a thermal crosslinker.

9. The thermal crosslinking agent is —CH ２ -OR ４ (However, R ４ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally cleavable group.

10. The photosensitive composition of claim 1 further comprising a thermal acid generator.

11. The photosensitive composition according to any one of claims 1 to 10, which is used for forming a planarizing film, an interlayer insulating film, or a bank material.

12. The photosensitive composition according to claim 11, which is for use in an organic EL device.

13. A cured film formed from the photosensitive composition according to any one of claims 1 to 10.

14. The cured film according to claim 13, which is a planarizing film, an interlayer insulating film, or a bank material.

15. a film-forming step of forming a coating film using the photosensitive composition according to any one of claims 1 to 10; an exposure step of exposing at least a portion of the coating film formed in the film formation step; a developing step of developing the coating film after exposure in the exposure step; a heating step of heating the coating film developed in the developing step; A method for producing a cured film, comprising:

16. The method for producing a cured film according to claim 15 , further comprising a step of exposing the coating film after development in the developing step and before heating in the heating step.

17. The method for producing a cured film according to claim 15 , further comprising a step of heating the coating film after development in the developing step and before heating in the heating step at a temperature lower than the heating temperature in the heating step.

18. A display device comprising the cured film according to claim 13.

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