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

Abstract

The invention provides a photosensitive composition capable of forming a hardened film with high sensitivity and excellent heat resistance, bending resistance and reprocessability, a hardened film and a manufacturing method thereof, and a display device. A photosensitive composition containing a polymer component and a quinonediazide compound, the polymer component including 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 the main chain, and the second structural unit having a methylene group bonded to a carbon atom constituting the cyclic ether structure in the main chain. 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 polymer (A) is contained in an amount of 25 mass% or more relative to the total amount of the polymer component.

Description

Technical Field

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

[0002] In various display devices including organic electroluminescence (EL) elements (organic EL elements) or liquid crystal display elements, insulating cured films such as planarization films, interlayer insulating films, and dam materials (also referred to as partition walls) are provided. In recent years, photosensitive compositions containing a polymer component and a photosensitive compound have been used to form these cured films. For example, for a coating film formed from a photosensitive composition, after irradiating with radiation through a mask having a pattern and then performing a development process, and then performing a heat treatment to thermally cure it, a patterned cured film can be obtained (for example, refer to Patent Document 1).

[0003] Patent Document 1 discloses the following: A cured film of an organic EL display device is formed by a photosensitive resin composition containing a polyimide precursor as an alkali-soluble resin and a quinone diazide compound.

[0004] [Prior Art Documents]

[0005] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2021-157173 Summary of the Invention

[0007] [Problems to be Solved by the Invention]

[0008] The cured film formed from a photosensitive composition based on a polyimide precursor or polyimide has excellent heat resistance. On the other hand, the sensitivity is not sufficient, and there is room for further improvement.

[0009] In addition, in the manufacturing process of the cured film, defects such as pinholes or coating film unevenness sometimes occur on the film formed on the substrate. Therefore, the temporarily formed cured film is often peeled off from the substrate for reusing (reprocessing) the substrate. In such reprocessing, it is required that the film can be easily peeled off from the substrate by bringing the film into contact with a solvent (that is, good reprocessability). However, polyimide generally has low solubility and poor reprocessability.

[0010] In recent years, in devices such as smartphones equipped with an organic EL display (organic light emitting diode, OLED), the application of flexible displays has been studied. The flexible display can be deformed into various shapes such as bending or folding back by using a flexible substrate such as a resin film. Therefore, for the hard film for display devices, it is sometimes required to have bend resistance (hereinafter, also referred to as "flexural resistance") that can cope with flexible displays.

[0011] The present invention has been completed in view of the above problems, and a main object thereof is to provide a photosensitive composition capable of forming a hard film having high sensitivity, excellent heat resistance, flexural resistance, and reprocessability.

[0012] [Means for Solving the Problems]

[0013] According to the present invention, there are provided the following photosensitive composition, hard film and its manufacturing method, and display device.

[0014] 〔1〕A photosensitive composition containing a polymer component and a quinone diazide compound. In the photosensitive composition, the polymer component includes a polymer (A) having a first structural unit and a second structural unit. The first structural unit has a cyclic ether structure in the main chain 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, and the polymer (A) is contained in an amount of 25% by mass or more based on the total amount of the polymer component.

[0015] 〔2〕A hard film formed from the photosensitive composition according to the above 〔1〕.

[0016] 〔3〕A method for manufacturing a hard film, including: a film forming step of forming a coating film using the photosensitive composition according to the above 〔1〕; an exposure step of exposing at least a part of the coating film; a developing step of developing the exposed coating film; and a heating step of heating the developed coating film.

[0017] 〔4〕A display device including the hard film according to the above 〔2〕.

[0018] [Effects of the Invention]

[0019] According to the present invention, a photosensitive composition capable of forming a hard film having high sensitivity, excellent heat resistance, flexural resistance, and reprocessability can be obtained. Detailed Embodiments

[0020] Hereinafter, matters related to the embodiments will be described in detail. In addition, in this specification, the numerical range described using "~" means that the numerical values described before and after "~" are included as the lower limit value and the upper limit value.

[0021] In this specification, "hydrocarbyl group" means a group including a linear hydrocarbyl group, an alicyclic hydrocarbyl group, and an aromatic hydrocarbyl group. The so-called "linear hydrocarbyl group" means a linear hydrocarbyl group and a branched hydrocarbyl group in which the main chain does not contain a cyclic structure but is composed only of a linear structure. Among them, the linear hydrocarbyl group can be saturated or unsaturated. The so-called "alicyclic hydrocarbyl group" means a hydrocarbyl group that contains only the structure of an alicyclic hydrocarbon as the ring structure and does not contain an aromatic ring structure. Among them, the alicyclic hydrocarbyl group does not need to be composed only of the structure of an alicyclic hydrocarbon, and also includes a group having a linear structure in a part thereof. The so-called "aromatic hydrocarbyl group" means a hydrocarbyl group that contains an aromatic ring structure as the ring structure. Among them, the aromatic hydrocarbyl group does not need to be composed only of an aromatic ring structure, and may also include a linear structure or an alicyclic hydrocarbon structure in a part thereof. The ring structure possessed by the alicyclic hydrocarbyl group and the aromatic hydrocarbyl group may also have a substituent containing a hydrocarbon structure.

[0022] The so-called "structural unit" is a unit that mainly constitutes the main chain structure, and means a unit that contains two or more units at least in the main chain structure. The so-called "main chain" of a polymer means the "main backbone" part that contains the longest chain of atoms in the polymer. The part of the so-called "main backbone" is allowed to contain a ring structure. For example, the so-called "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. The so-called "side chain" means a part branched from the part of the "main backbone" of the polymer. "(Meth)acrylic acid" is a term that includes "acrylic acid" and "methacrylic acid".

[0023] "Photosensitive Composition"

[0024] The photosensitive composition of the present disclosure (hereinafter, also referred to as "this composition") contains a polymer component and a quinone diazide compound. Hereinafter, each component contained in this composition and other components formulated as needed will be described.

[0025] <Polymer Component>

[0026] This composition contains a polymer (A) having a first structural unit and a second structural unit shown below as the polymer component.

[0027] First structural unit: A structural unit having a cyclic ether structure in the main chain and a methylene group bonded to a carbon atom constituting the cyclic ether structure

[0028] 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

[0029] (Polymer (A))

[0030] · The first structural unit

[0031] The cyclic ether structure of the first structural unit preferably has 5 or 6 ring members. Specifically, a tetrahydrofuran ring structure or a tetrahydropyran ring structure can be cited. The first structural unit only needs to have a cyclic ether structure and a partial structure in which the methylene group bonded to the carbon atom constituting the cyclic ether structure is introduced into the polymer main chain. As a preferred specific example, a repeating unit having the following structure can be cited: the methylene group constituting the polymer main chain in each first structural unit is one or two, and the main chain portion of the polymer constituted by the first structural unit includes a cyclic ether structure and one or two methylene groups. In addition, the cyclic ether structure of the first structural unit may have a substituent in the ring portion.

[0032] More specifically, the first structural unit is preferably a structural unit represented by the following formula (1).

[0033] [Chemical formula 1]

[0034]

[0035] (In formula (1), R 1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms. R 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. n is 0 or 1)

[0036] In the formula (1), as the monovalent hydrocarbon group having 1 to 30 carbon atoms represented by R 1 or R 3 , the following can be cited: a linear or branched saturated hydrocarbon group having 1 to 30 carbon atoms, a linear or branched unsaturated hydrocarbon group having 2 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and an aromatic hydrocarbon group having 6 to 30 carbon atoms.

[0037] As specific examples of the linear or branched saturated hydrocarbon group having 1 to 30 carbon atoms, the following can be cited: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, tert-pentyl, hexyl, heptyl, octyl, nonyl, decyl, etc. As specific examples of the linear or branched unsaturated hydrocarbon group having 2 to 30 carbon atoms, the following can be cited: alkenyl groups such as vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl; alkynyl groups such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, etc.

[0038] As the alicyclic hydrocarbon group having 3 to 30 carbon atoms, a group having an alicyclic monocyclic hydrocarbon structure having 3 to 30 carbon atoms or an alicyclic polycyclic hydrocarbon structure having 6 to 30 carbon atoms can be cited as the group having a ring structure. The alicyclic monocyclic hydrocarbon structure having 3 to 30 carbon atoms and the alicyclic polycyclic hydrocarbon structure having 6 to 30 carbon atoms can be either saturated or unsaturated. Specific examples of the ring possessed by the alicyclic hydrocarbon group include: cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclooctane ring, cyclopentene ring, cyclohexene ring, cycloheptene ring, cyclooctene ring, cyclodecene ring, norbornane ring, bicyclo[2.2.2]octane ring, adamantane ring, etc.

[0039] As the aromatic hydrocarbon group having 6 to 30 carbon atoms, a group having an aromatic monocyclic hydrocarbon structure having 6 to 30 carbon atoms or an aromatic polycyclic hydrocarbon structure having 6 to 30 carbon atoms can be cited as the group having a ring structure. Specific examples of the ring possessed by the aromatic hydrocarbon group include: benzene ring, naphthalene ring, anthracene ring, indene ring, fluorene ring, etc.

[0040] R 1 or R 3 Preferably, they are each a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and more preferably a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms.

[0041] As specific examples of the first structural unit, structural units represented by the following formulas (1-1) to (1-11) can be cited respectively.

[0042] [Chemical formula 2]

[0043]

[0044] In addition, for example, by polymerizing a diene compound represented by the following formula (1A) as a monomer, the structural unit represented by the formula (1) can be introduced into the polymer. Preferred specific examples of the diene compound include: methyl 2-(allyloxymethyl)(meth)acrylate, ethyl 2-(allyloxymethyl)(meth)acrylate, n-propyl 2-(allyloxymethyl)(meth)acrylate, etc.

[0045] [Chemical formula 3]

[0046]

[0047] (In the formula (1A), R 1 and R 2 have the same meanings as in the formula (1))

[0048] The content ratio of the first structural unit in the polymer (A) is preferably 1% by mass to 60% by mass with respect to all the structural units constituting the polymer (A). By setting the content ratio of the first structural unit within the above range, a cured film having more excellent heat resistance and bending resistance can be obtained. From the viewpoint of obtaining a cured film having excellent heat resistance and bending resistance, the content ratio of the first structural unit in the polymer (A) is more preferably 2% by mass or more, and further preferably 5% by mass or more. In addition, from the viewpoint of suppressing pattern collapse due to melting of this composition during heating (post-baking) at a relatively high temperature during film formation, the content ratio of the first structural unit is more preferably 55% by mass or less, and further preferably 50% by mass or less with respect to all the structural units constituting the polymer (A).

[0049] · The second structural unit

[0050] 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 (wherein the first structural unit is excluded). By the polymer (A) further having the second structural unit, the solubility (alkali solubility) of the polymer (A) in an alkali developer can be improved, or the curing reactivity can be improved.

[0051] Examples of the acid group include a carboxyl group, a sulfonic acid group, a phenolic hydroxyl group, etc. In addition, in this specification, the so-called "phenolic hydroxyl group" means a hydroxyl group directly bonded to an aromatic ring (such as a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, etc.).

[0052] Specifically, the second structural unit is preferably at least one selected from the group consisting of a structural unit having a carboxyl group, a structural unit having a sulfonic acid group, a structural unit having a phenolic hydroxyl group, and a maleimide unit. In terms of further improving the alkali solubility of the polymer (A), the polymer (A) preferably contains at least one selected from the group consisting of a structural unit having a carboxyl group, a structural unit having a sulfonic acid group, and a maleimide unit (hereinafter, also referred to as "structural unit 2A") as the second structural unit, and more preferably contains at least one selected from the group consisting of a structural unit having a carboxyl group and a maleimide unit as the second structural unit. Among these, the maleimide unit is preferred in terms of improving storage stability.

[0053] The monomer providing the structural unit 2A is not particularly limited as long as it can copolymerize with the monomer providing the first structural unit. Specific examples of the monomer providing the structural unit 2A include, as the monomer providing a structural unit having a carboxyl group, for example: unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, 4-vinylbenzoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, etc.; as the monomer providing a structural unit having a sulfonic acid group, for example: vinylsulfonic acid, (meth)allylsulfonic acid, styrenesulfonic acid, (meth)acryloyloxyethylsulfonic acid, etc. In addition, maleimide can also be used as the monomer providing the structural unit 2A.

[0054] In terms of being able to improve the sensitivity of the present composition while imparting alkali developability, the polymer (A) preferably contains 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 the structural unit 2B include the structural unit represented by the following formula (2-1) and the structural unit represented by the following formula (2-2).

[0055] [Chemical formula 4]

[0056]

[0057] (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. X 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 represents the bonding bond of the carbon atom bonded to R A . A 1 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. 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. Among them, m1 + n1 ≤ 5, m2 + n2 ≤ 7. When n1 is 2 or more, the plurality of A 1 are the same or different. When n2 is 2 or more, the plurality of A 1 are the same or different)

[0058] 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, relative to X 1The carbon atoms to which they are bonded, and the position of the hydroxyl group bonded to the benzene ring in the formula (2-1) can be any one of ortho, meta, and para positions. From the viewpoint of increasing the difference in solubility between the exposed part and the unexposed part, m1 and m2 are preferably 1 to 3, more preferably 1 or 2.

[0059] As a specific example of the structural unit 2B, the structural units represented by the following formulas can be cited.

[0060] [Chemical formula 5]

[0061]

[0062] As specific examples of the monomer that provides the structural unit 2B, the following can be cited: 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-hydroxybenzyl (meth)acrylate, 3-hydroxybenzyl (meth)acrylate, 4-hydroxybenzyl (meth)acrylate, 3-hydroxynaphthyl (meth)acrylate, 4-hydroxynaphthyl (meth)acrylate, etc.

[0063] In the polymer (A), from the viewpoint of imparting good solubility to the polymer in an alkali developer, the content ratio of the second structural unit is preferably 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 2% by mass or more, relative to all the structural units constituting the polymer (A). Further, from the viewpoint of sufficiently generating a difference in solubility in the alkali developer between the exposed part and the unexposed part to obtain a pattern with a good shape, the content ratio of the second structural unit is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less, relative to all the structural units constituting the polymer (A).

[0064] In addition, from the viewpoint of imparting good solubility to the alkali developer, the content ratio of the structural unit 2A is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and still more preferably 1% by mass or more, relative to all the structural units constituting the polymer (A). Further, from the viewpoint of obtaining a pattern with a good shape, the content ratio of the structural unit 2A is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less, relative to all the structural units constituting the polymer (A).

[0065] The polymer (A) preferably has structural unit 2A and structural unit 2B as the second structural units. By using structural unit 2A and structural unit 2B in combination, the sensitivity can be further improved compared to using structural unit 2A alone. In terms of being able to impart good solubility in an alkali developer while sufficiently improving the sensitivity of the present composition, the content ratio of structural unit 2B is preferably 0.5% by mass or more, more preferably 1% by mass or more, and still more preferably 2% by mass or more, relative to all the structural units constituting the polymer (A). In addition, in order to obtain a pattern with a good shape, the content ratio of structural unit 2B is preferably 40% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less, relative to all the structural units constituting the polymer (A).

[0066] · Other structural units

[0067] 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.

[0068] The polymer (A) preferably further contains a structural unit having an oxiranyl group or an oxetanyl group (hereinafter, referred to as "the third structural unit"). Here, by introducing the first structural unit into the polymer, the bending resistance of the cured film formed from the present composition can be improved. On the other hand, by introducing a methylene group into the polymer main chain, it is considered that the film is likely to melt during the heating step (post-baking) during film formation. In terms of the above aspects, by introducing the first structural unit and the third structural unit into the polymer together, a crosslinked structure can be formed between or within the molecules of the polymer (A), thereby suppressing the melting of the film even when heating is performed at a relatively high temperature during film formation.

[0069] The third structural unit is preferably a structural unit derived from an unsaturated monomer having an oxiranyl group or an oxetanyl group. Specifically, it is preferably at least one selected from the group consisting of the structural unit represented by the following formula (3-1) and the structural unit represented by the following formula (3-2).

[0070] [Chemical formula 6]

[0071]

[0072] (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. R 30 is a monovalent group having an oxiranyl group or an oxetanyl group. X 2 is a single bond or a divalent linking group. R 31is 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 Rs 31 are the same or different)

[0073] In the formulas (3-1) and (3-2), as R 30 , examples include: oxiranyl, oxetanyl, 3,4-epoxycyclohexyl, 3,4-epoxytricyclo[5.2.1.0 2,6 decyl, 3-ethyloxetanyl, and the like.

[0074] As the divalent linking group in X 2 , examples include: alkanediyls such as methylene, ethylene, 1,3-propanediyl; divalent groups in which any methylene group of an alkanediyl having 2 to 10 carbon atoms is substituted with an oxygen atom, and the like.

[0075] Specific examples of the monomer providing the third structural unit include, for example: 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 [3,4-epoxytricyclo(5.2.1.0 2,6 )decane-9-yl] methacrylate, (3-methyloxetane-3-yl)methyl (meth)acrylate, (3-ethyloxetane-3-yl)methyl (meth)acrylate, (oxetane-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.

[0076] When the polymer (A) contains the third structural unit, in order to sufficiently suppress the melting of the film during the heating step (post-baking) during film formation, the content ratio of the third structural unit in the polymer (A) is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably 5% by mass or more, relative to all the structural units constituting the polymer (A). Further, from the viewpoint of ensuring the content ratios of the first structural unit and the second structural unit in the polymer (A), the content ratio of the third structural unit is preferably 75% by mass or less, more preferably 65% by mass or less, and still more preferably 60% by mass or less, relative to all the structural units constituting the polymer (A).

[0077] The polymer (A) preferably contains a structural unit having an alicyclic epoxy group as the third structural unit. By the polymer (A) containing a structural unit having an alicyclic epoxy group, while achieving a low dielectric constant of the film, the melt resistance of the film formed from the present composition can be further improved. Herein, the so-called "alicyclic epoxy group" is a group formed by bonding two adjacent carbon atoms in the carbon atoms constituting the alicyclic ring to the same oxygen atom. For example, 3,4-epoxycyclohexyl, 3,4-epoxytricyclo[5.2.1.0 2,6 decyl, etc.

[0078] With respect to all the structural units constituting the polymer (A), the content ratio of the structural unit 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 still more preferably 5% by mass or more. In addition, with respect to all the structural units constituting the polymer (A), the content ratio of the structural unit having an alicyclic epoxy group is preferably 60% by mass or less, more preferably 55% by mass or less, and still more preferably 50% by mass or less.

[0079] As specific examples of the monomers providing other structural units contained in the polymer (A), in addition to those described above, for example, (meth)acrylic acid alkyl esters, (meth)acrylic esters having an alicyclic structure, (meth)acrylic 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, silyl group-containing vinyl compounds, etc. can be cited.

[0080] Regarding specific examples of these, as the (meth)acrylic acid alkyl ester, (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid n-propyl ester, (meth)acrylic acid isopropyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid n-lauryl ester, (meth)acrylic acid n-stearyl ester, etc. can be cited;

[0081] As the (meth)acrylic ester having an alicyclic structure, (meth)acrylic acid cyclohexyl ester, (meth)acrylic acid 2-methylcyclohexyl ester, (meth)acrylic acid tricyclo[5.2.1.0 2,6 decane-8-yl ester, (meth)acrylic acid tricyclo[5.2.1.0 2,5 decane-8-yloxyethyl ester, (meth)acrylic acid isobornyl ester, etc. can be cited;

[0082] As the (meth)acrylic ester having an aromatic ring structure, (meth)acrylic acid phenyl ester, (meth)acrylic acid benzyl ester, etc. can be cited;

[0083] Examples of the aromatic vinyl compound include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 5-tert-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, diphenylethylene, vinylnaphthalene, vinylpyridine, etc.;

[0084] Examples of the N-substituted maleimide compound include N-cyclohexylmaleimide, N-cyclopentylmaleimide, N-(2-methylcyclohexyl)maleimide, N-(4-methylcyclohexyl)maleimide, N-(4-ethylcyclohexyl)maleimide, N-(2,6-dimethylcyclohexyl)maleimide, N-norbornenylmaleimide, 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, N-naphthylmaleimide, etc.;

[0085] Examples of the vinyl compound 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, glycerol carbonate (meth)acrylate, (γ-lactam-2-yl) (meth)acrylate, N-(meth)acryloxyethylhexahydrophthalimide, etc.;

[0086] Examples of the conjugated diene compound include 1,3-butadiene, isoprene, etc.;

[0087] Examples of the nitrogen-containing vinyl compound include (meth)acrylonitrile, (meth)acrylamide, etc.;

[0088] Examples of the unsaturated dicarboxylic acid dialkyl ester compound include diethyl itaconate, etc.;

[0089] Examples of the silicon-alkyl-containing vinyl compound include: styryltrimethoxysilane, styryltriethoxysilane, styrylmethyldimethoxysilane, styrylethyldiethoxysilane, styryldimethoxyhydroxysilane, styryldiethoxyhydroxysilane, 4-vinylphenyltrimethoxysilane, (meth)acryloxyphenyltrimethoxysilane, (meth)acryloxyphenyltriethoxysilane, (meth)acryloxyphenylmethyldimethoxysilane, (meth)acryloxyphenylethyldiethoxysilane, trimethoxy(4-vinylnaphthyl)silane, triethoxy(4-vinylnaphthyl)silane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 4-(meth)acryloxybutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-isopropenylphenyloxythimethylsilane, 4-isopropenylphenyloxythiethylsilane, etc. In addition, examples of the monomer that provides other structural units include monomers such as vinyl chloride, vinylidene chloride, and vinyl acetate, in addition to those described above.

[0090] When the polymer (A) contains a structural unit having a hydrocarbon ring (excluding the first to third structural units, which is also referred to as the "fourth structural unit") as another structural unit, even when heating (post-baking) is performed at a relatively high temperature during film formation, melting of the film can be sufficiently suppressed, and in this regard, it is preferred. The hydrocarbon ring may be an alicyclic ring or an aromatic ring. Examples of the alicyclic ring include: cyclopentane ring, cyclohexane ring, cyclohexene ring, norbornane ring, adamantane ring, tricyclo[5.2.1.0 2,5 decane ring, etc. Examples of the aromatic ring include: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, etc. Specific examples of the fourth structural unit include structural units derived from monomers having a hydrocarbon ring among the monomers exemplified above as monomers that provide other structural units.

[0091] When the polymer (A) contains the fourth structural unit, the content ratio of the fourth structural unit is preferably 1% by mass or more, more preferably 2% by mass or more, relative to all the structural units constituting the polymer (A). In addition, the content ratio of the fourth structural unit is preferably 50% by mass or less, more preferably 45% by mass or less, relative to all the structural units constituting the polymer (A).

[0092] · Manufacture of Polymer (A)

[0093] The polymer (A) can be produced, for example, by using monomers capable of introducing the respective structural units in an appropriate solvent in the presence of a polymerization initiator or the like 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 dimethyl 2,2'-azobis(isobutyrate). The use ratio of the polymerization initiator is preferably set to 0.01 part by mass to 30 parts by mass relative to 100 parts by mass of the total amount of the monomers used in the reaction. Examples of the polymerization solvent include alcohols, ethers, ketones, esters, hydrocarbons, and the like. The amount of the polymerization solvent used is preferably set to such an amount that the total amount of the monomers used in the reaction is 0.1% by mass to 60% by mass relative to the total amount of the reaction solution.

[0094] In the synthesis of the 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 preferred range. For example, relative to 100 parts by mass of the total amount of the monomers used in the synthesis of the polymer (A), the amount of the monomer providing the first structural unit is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and still more preferably 5 parts by mass or more. In addition, relative to 100 parts by mass of the total amount of the monomers used in the synthesis of the polymer (A), the amount of the monomer providing the first structural unit is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and still more preferably 50 parts by mass or less.

[0095] Relative to 100 parts by mass of the total amount of the monomers used in the synthesis of the polymer (A), the amount of the monomer providing the second structural unit is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, and still more preferably 2 parts by mass or more. In addition, relative to 100 parts by mass of the total amount of the monomers used in the synthesis of the polymer (A), the amount of the monomer providing the second structural unit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less.

[0096] Relative to 100 parts by mass of the total amount of the monomers used in the synthesis of the polymer (A), the amount of the monomer providing the third structural unit is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and still more preferably 5 parts by mass or more. In addition, relative to 100 parts by mass of the total amount of the monomers used in the synthesis of the polymer (A), the amount of the monomer providing the third structural unit is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and still more preferably 50 parts by mass or less.

[0097] In the polymerization, the reaction temperature is generally 30°C to 180°C. The reaction time varies depending on the type of polymerization initiator and monomer or the reaction temperature, but is generally 0.5 hour to 10 hours. The polymer obtained by the polymerization reaction can be directly used for the preparation of the photosensitive composition in a state dissolved in the reaction solution, or can be used for the preparation of the photosensitive composition after being separated from the reaction solution. Separation of the polymer can be carried out, for example, by injecting the reaction solution into a large amount of poor solvent and drying the precipitate thus obtained under reduced pressure; by known separation methods such as a method of distilling off the reaction solution under reduced pressure using an evaporator.

[0098] The polystyrene-converted weight-average molecular weight (Mw) of the polymer (A) obtained by gel permeation chromatography (GPC) is preferably 2,000 or more. If Mw is 2,000 or more, a cured film having sufficiently high heat resistance or chemical resistance and showing good developability can be obtained, and it is preferable in this regard. The Mw of the polymer (A) is more preferably 5,000 or more, further preferably 6,000 or more, and particularly preferably 7,000 or more. In addition, from the viewpoint of good film-forming properties, the Mw of the polymer (A) is preferably 50,000 or less, more preferably 30,000 or less, further preferably 20,000 or less, and particularly preferably 15,000 or less.

[0099] For the polymer (A), the molecular weight distribution (Mw / Mn) represented by the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) converted to polystyrene obtained by GPC is preferably 4.0 or less, more preferably 3.0 or less, and further preferably 2.5 or less.

[0100] This composition may contain the polymer (A) alone as a polymer component, or may further contain a polymer different from the 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. As the monomers constituting the other polymer, the same compounds as those exemplified in the description of the polymer (A) that provide the second structural unit, the third structural unit, or other structural units can be cited.

[0101] The content of polymer (A) in the present composition is 25% by mass or more relative to the total amount of the polymer components contained in the present composition. If the content of polymer (A) is less than 25% by mass relative to the total amount of the polymer components contained in the present composition, the effects of improving the bending resistance and reprocessability of the cured film obtained using the present composition with good balance cannot be sufficiently obtained. From this viewpoint, the content of polymer (A) is preferably 30% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, and particularly preferably 60% by mass or more relative to the total amount of the polymer components contained in the present composition.

[0102] <Quinonediazide compound>

[0103] The quinonediazide compound is a radiation-sensitive acid generator that generates carboxylic acid upon irradiation with radiation. As the quinonediazide compound, a condensate of a phenolic compound or an alcoholic compound (hereinafter also referred to as "parent nucleus") and 1,2-naphthoquinonediazide sulfonyl halide is preferably used.

[0104] As the mother nucleus, for example, the following can be mentioned: trihydroxybenzophenone, tetrahydroxybenzophenone, pentahydroxybenzophenone, hexahydroxybenzophenone, (polyhydroxyphenyl)alkane, and other mother nuclei. Specific examples of these are as follows: as trihydroxybenzophenone, for example, 2,3,4-trihydroxybenzophenone, 2,4,6-trihydroxybenzophenone, etc.; as tetrahydroxybenzophenone, for example, 2,2',4,4'-tetrahydroxybenzophenone, 2,3,4,3'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3,4,2'-tetrahydroxy-4'-methyldibenzophenone, 2,3,4,4'-tetrahydroxy-3'-methoxydibenzophenone, etc.; as pentahydroxybenzophenone, for example, 2,3,4,2',6'-pentahydroxybenzophenone, etc.; as hexahydroxybenzophenone, for example, 2,4,6,3',4',5'-hexahydroxybenzophenone, 3,4,5,3',4',5'-hexahydroxybenzophenone, etc.; as (polyhydroxyphenyl)alkane, for example, bis(2,4-dihydroxyphenyl)methane, bis(p-hydroxyphenyl)methane, 1,1,1-tris(p-hydroxyphenyl)methane, 1,1,1-tris(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'-tetramethyl-1,1'-spirobisindene-5,6,7,5',6',7'-hexol, 2,2,4-trimethyl-7,2',4'-trihydroxyflavane, etc.; as other mother nuclei, for example, 2-methyl-2-(2,4-dihydroxyphenyl)-4-(4-hydroxyphenyl)-7-hydroxychromane, 2-[bis{(5-isopropyl-4-hydroxy-2-methyl)phenyl}methyl], etc.

[0105] As the mother nucleus, 2,3,4,4'-tetrahydroxybenzophenone, 1,1,1-tris(p-hydroxyphenyl)methane, 1,1,1-tris(p-hydroxyphenyl)ethane, and 4,4'-[1-[4-[1-[4-hydroxyphenyl]-1-methylethyl]phenyl]ethylidene]bisphenol among these are preferred.

[0106] As 1,2-naphthoquinone diazosulfonyl halide, 1,2-naphthoquinone diazosulfonyl chloride is preferred. Specifically, 1,2-naphthoquinone diazo-4-sulfonyl chloride, 1,2-naphthoquinone diazo-5-sulfonyl chloride, etc. can be mentioned. Among these, 1,2-naphthoquinone diazo-5-sulfonyl chloride can be preferably used as 1,2-naphthoquinone diazosulfonyl halide.

[0107] In the condensation reaction for obtaining the condensate, regarding the ratio of the parent nucleus to 1,2-naphthoquinone diazide sulfonyl halide, the amount of 1,2-naphthoquinone diazide sulfonyl halide used is set to an amount corresponding to 30 mol% to 85 mol%, more preferably 50 mol% to 70 mol% relative to the number of OH groups in the parent nucleus. In addition, the condensation reaction can be carried out according to a known method. A 1,2-quinone diazide compound can be obtained by the condensation reaction of the parent nucleus and 1,2-naphthoquinone diazide sulfonyl halide. [[ID=!]]

[0108] In this composition, relative to 100 parts by mass of the polymer component contained in this 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 still more preferably 10 parts by mass or more. In addition, relative to 100 parts by mass of the polymer component, the content of the quinone diazide compound is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, and still more preferably 40 parts by mass or less. If the content of the quinone diazide compound is set to 2 parts by mass or more, sufficient acid is generated by irradiating this composition with radiation, and the difference in solubility between the irradiated part and the non-irradiated part of the radiation relative to the alkali solution can be sufficiently increased. Thereby, good patterning can be carried out. In addition, the amount of acid participating in the reaction with the polymer component can be increased, and heat resistance and chemical resistance liquid can be sufficiently ensured. On the other hand, if the content of the quinone diazide compound is set to 100 parts by mass or less, unreacted quinone diazide compound can be sufficiently reduced, and the decrease in developability caused by the remaining quinone diazide compound can be suppressed.

[0109] <Other components>

[0110] This composition may also contain components different from the polymer component and the quinone diazide compound (hereinafter, also referred to as "other components") together with the polymer component and the quinone diazide compound. Examples of other components include: heat crosslinking agents, thermal acid generators, adhesion aids, solvents, etc.

[0111] (Heat crosslinking agent)

[0112] The heat crosslinking agent may be any compound having a functional group (hereinafter, also referred to as "crosslinking group") that can react with the reaction sites (for example, ortho or para positions relative to the hydroxyl group of the phenolic structure, carboxyl group, alcoholic hydroxyl group, amino group, etc.) possessed by the polymer (A) by heating, and there is no particular limitation. Examples of the crosslinking group include: isocyanate group, protected isocyanate group, cyclic carbonate group, hydroxymethyl group, protected hydroxymethyl group, alkoxymethyl group, group having a ketene structure, and group having a mesityl oxide structure, etc. The number of crosslinking groups possessed by the heat crosslinking agent is preferably 2 to 10, more preferably 2 to 6.

[0113] As the thermal crosslinking agent, a compound having "-CH2-OR 4 " represented by the group (wherein, R 4 is a hydrogen atom, an alkyl group with 1 to 3 carbon atoms, or a thermally cleavable group) (hereinafter also referred to as a "hydroxymethyl crosslinking agent"). 4 In the above, examples of the thermally detachable group include tert-butyl, benzyl, acetyl, methoxymethyl, 2-tetrahydropyranyl, and 2-tetrahydrofuranyl.

[0114] Specific examples of the methylol-based crosslinking agent 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).

[0115] [Chemistry 7]

[0116]

[0117] The molecular weight of the thermal crosslinking agent is preferably 80 or more, more preferably 100 or more, and even more preferably 150 or more. Furthermore, the molecular weight of the thermal crosslinking agent is preferably 500 or less, more preferably 450 or less, and even more preferably 400 or less. When the molecular weight of the thermal crosslinking agent is within the above range, it is possible to suppress a decrease in sensitivity and development solubility of the present composition while improving the melt resistance of the film and achieving a low dielectric constant, which is preferred from these perspectives.

[0118] The content of the thermal crosslinking agent in the present composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 2 parts by mass or more, relative to 100 parts by mass of the polymer component. Furthermore, the content of the thermal crosslinking agent is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, relative to 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 present composition can be fully achieved. Furthermore, 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 fully reduced.

[0119] (Thermal Acid Generator)

[0120] A thermal acid generator is a component that generates an acid upon heating. In particular, when using a hydroxymethyl crosslinking agent as a thermal crosslinking agent, the action of the acid generated by the thermal acid generator upon heating can be utilized to accelerate the crosslinking reaction performed by the hydroxymethyl crosslinking agent. This can enhance the effectiveness of suppressing film melting caused by heating (post-baking) during the formation of the cured film.

[0121] As the thermal acid generator, a compound known as a thermal acid generator formulated in a polymer composition for forming a cured film can be suitably used. Specific examples of the thermal acid generator include: 4-hydroxyphenyldimethylsulfonium trifluoromethanesulfonate, benzyl-4-hydroxyphenylmethylsulfonium trifluoromethanesulfonate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, 2-methylbenzyl-4-hydroxyphenylmethylsulfonium trifluoromethanesulfonate, 4-acetoxyphenyldimethylsulfonium trifluoromethanesulfonate, 4-acetoxyphenylbenzylmethylsulfonium trifluoromethanesulfonate, 4-(methoxycarbonyloxy)phenyldimethylsulfonium trifluoromethanesulfonate, benzyl-4-(methoxycarbonyloxy)phenylmethylsulfonium trifluoromethanesulfonate, benzyl-4-(methoxycarbonyloxy)phenylmethylsulfonium hexafluorophosphate, and the like.

[0122] From the viewpoint of suppressing the melting of the film during heating (post-baking) to obtain a pattern with a desired shape, the content of the thermal acid generator in this composition is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more, and still more preferably 0.5 part by mass or more, based on 100 parts by mass of the polymer component contained in this composition. In addition, 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 still more preferably 3 parts by mass or less, based on 100 parts by mass of the polymer component contained in this composition.

[0123] (Adhesion promoter)

[0124] The adhesion promoter is a component that improves the adhesion between the cured film formed using this composition and the substrate. As the adhesion promoter, a functional silane coupling agent having a reactive functional group can be preferably used. Examples of the reactive functional group possessed by the functional silane coupling agent include: carboxyl group, (meth)acryloyl group, oxiranyl group, oxetanyl group, vinyl group, isocyanate group, amino group, and the like.

[0125] As specific examples of the functional silane coupling agent, for example, trimethoxysilylbenzoic acid, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 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-butylene)propylamine, N-methyl-3-(trimethoxysilyl)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, etc. can be cited.

[0126] With respect to 100 parts by mass of the polymer component, the content of the adhesion promoter in the present composition is preferably 30 parts by mass or less, more preferably 20 parts by mass or less.

[0127] (Solvent)

[0128] The present composition is a liquid composition in which the polymer component, the quinone diazide compound, and other optionally blended components are preferably dissolved or dispersed in a solvent. As the solvent, an organic solvent that dissolves the components formulated in the present composition and does not react with the components is preferred.

[0129] As specific examples of the solvent, for example, 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 glycol monomethyl ether, ethylene glycol 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; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene. Among 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 acetates, diethylene glycols, propylene glycol monoalkyl ethers, and propylene glycol monoalkyl ether acetates.

[0130] As other components, in addition to those listed above, for example, antioxidants, acid diffusion control agents, ortho - esters, polyfunctional polymerizable compounds (such as polyfunctional (meth)acrylates), surfactants (fluorine - based surfactants, silicone - based surfactants, non - ionic surfactants, etc.), polymerization inhibitors, chain transfer agents, etc. can be listed. The blending ratios of these components can be appropriately selected according to each component within the range that does not impair the effects of the present disclosure.

[0131] The solid content concentration of the present composition (the ratio of the total mass of the components other than the solvent in the photosensitive composition to the total mass of the photosensitive composition) can be appropriately selected in consideration of viscosity or volatility, etc. The solid content concentration of the present composition is preferably in the range of 5% by mass to 60% by mass. If the solid content concentration is 5% by mass or more, the film thickness of the coating film can be sufficiently ensured when the present composition is coated on a substrate. In addition, if the solid content concentration is 60% by mass or less, the film thickness of the coating film will not be too large, and furthermore, the viscosity of the photosensitive composition can be moderately increased, and good coatability can be ensured. The solid content concentration of the present composition is more preferably 10% by mass to 55% by mass, and still more preferably 12% by mass to 50% by mass.

[0132] "Hardened Film and Its Manufacturing Method"

[0133] The hardened film of the present invention is formed from the photosensitive composition prepared as described above. The photosensitive composition can form a hardened film having high sensitivity and excellent bending resistance, re - processability, and heat resistance. Such a photosensitive composition of the present invention is preferably used for forming a planarization film, an interlayer insulating film, or a dam material (also called a partition wall), and particularly preferably used for an organic EL element. Among these, the present composition is particularly preferably used as a material for forming a planarization film for an organic EL element.

[0134] When manufacturing the hardened film, by using the photosensitive composition of the present invention, a positive - type hardened film can be formed. The hardened film can be manufactured by using the present composition, for example, by a method including the following steps 1 to 4.

[0135] Step 1: A step of forming a coating film using the photosensitive composition of the present invention (film - forming step)

[0136] Step 2: A step of exposing at least a part of the coating film formed by the film - forming step (exposure step)

[0137] Step 3: A step of developing the coating film after exposure in the exposure step (development step)

[0138] Step 4: A step of heating the coating film developed in the development step (heating step)

[0139] Hereinafter, each step will be described in detail.

[0140] [Process 1: Film Formation Process]

[0141] In Process 1, the present composition is applied to the surface where the film is to be formed (hereinafter also referred to as the "film-forming surface"), and preferably, the solvent is removed by heat treatment (pre-baking) to form a coating film on the film-forming surface. The material of the film-forming surface is not particularly limited. For example, when a planarization film is formed from the present composition, the present composition is applied to a substrate provided with switching elements such as thin film transistors (TFTs), and a coating film is formed. As the substrate, for example, a glass substrate, a silicon substrate, or a resin substrate is used. On the surface of the substrate on which the coating film is formed, a metal thin film according to the use may also be formed, and various surface treatments such as hexamethyldisilazane (HMDS) treatment may also be performed.

[0142] As the coating method of the present composition, for example, spraying method, roll coating method, spin coating method, slit die coating method, bar coating method, inkjet method, etc. can be cited. Among these, it is preferably carried out by spin coating method, slit die coating method or bar coating method. As the pre-baking conditions, they also vary depending on the types and content ratios of the respective components of the present composition. For example, it is carried out at 60°C to 120°C for 0.5 minutes to 10 minutes. The film thickness of the formed coating film (i.e., the film thickness after pre-baking) is preferably 0.1 μm to 12 μm. For the present composition applied to the film-forming surface, reduced pressure drying (vacuum dry, VCD) may also be carried out before pre-baking.

[0143] [Process 2: Exposure Process]

[0144] In Process 2, at least a part of the coating film formed in Process 1 is irradiated with radiation. At this time, by irradiating the coating film with radiation through a mask having a specified pattern, a hardened film having a pattern can be formed. As the radiation, for example, ultraviolet rays, far ultraviolet rays, visible light, X-rays, charged particle beams such as electron beams, etc. can be cited. Among these, ultraviolet rays are preferred. For example, g rays (wavelength 436 nm), i rays (wavelength 365 nm) can be cited. As the exposure amount of the radiation, it is preferably 0.1 J / m 2 ~20,000 J / m 2 .

[0145] [Process 3: Development Process]

[0146] In Step 3, the radiation-exposed coating film in Step 2 is developed. Specifically, positive development is performed on the radiation-exposed coating film in Step 2 using a developer to remove the radiation-exposed portion. As the developer, for example, an aqueous solution of an alkali (alkaline compound) can be cited. As the alkali, for example, sodium hydroxide, tetramethylammonium hydroxide, and the alkalis exemplified in paragraph

[0127] of Japanese Patent Laid-Open No. 2016-145913 can be cited. Regarding the alkali concentration of the alkali aqueous solution, from the viewpoint of obtaining appropriate developability, it is preferably 0.1% by mass to 5% by mass. As the developing method, appropriate methods such as the liquid covering method, dipping method, shaking dipping method, and spraying method can be cited. The development time also varies depending on the composition of the composition and is, for example, 30 seconds to 120 seconds. In addition, it is preferable to perform a rinsing treatment of washing the patterned coating film with running water after the developing step.

[0147] [Step 4: Heating Step]

[0148] In Step 4, a treatment of heating the developed coating film in Step 3 (post-baking) is performed. Post-baking can be performed using a heating device such as an oven or a hot plate, for example. Regarding the post-baking conditions, the heating temperature is, for example, 150°C to 260°C. For example, when performing the heating treatment on a hot plate, the heating time is 5 minutes to 40 minutes, and when performing the heating treatment in an oven, the heating time is 10 minutes to 80 minutes. Through the above heating treatment, a curing reaction is carried out, and a cured film having a target pattern can be formed on the substrate. The shape of the pattern of the cured film is not particularly limited, and examples include: line and space patterns, dot patterns, hole patterns, and lattice patterns.

[0149] When manufacturing the cured film, in addition to including the above Steps 1 to 4, a post-exposure step after development, a preheating step, or both of these may also be included.

[0150] Post-exposure step after development: A step of exposing the coating film after development by the developing step of Step 3 and before heating by the heating step of Step 4

[0151] Preheating step: A step of heating the coating film at a temperature lower than the heating temperature of the heating step of Step 4 after development by the developing step of Step 3 and before heating by the heating step of Step 4

[0152] [Post-exposure step after development]

[0153] When manufacturing a hardened film using this composition, it is preferable to expose the coating film after development in the development process and before heating in the heating process. By setting such a process (post-development exposure process), the naphthoquinone diazide compound can be faded, and the transmittance of the coating film can be increased. It is preferable to expose the entire substrate surface through the post-development exposure process. For specific examples and preferred examples of the type of radiation and the exposure amount, the description of the exposure process in Process 2 can be applied. For example, with an exposure amount of 500 J / m 2 ~5,000 J / m 2 Expose the entire substrate surface to a mixture of ghi rays.

[0154] [Preheating process]

[0155] When manufacturing a hardened film using this composition, it is preferable to heat the coating film at a temperature lower than the heating temperature of the heating process after development in the development process of Process 3 and before heating in the heating process of Process 4. By setting the preheating process, the following situation can be suppressed: the coating film melts due to the relatively high-temperature heating in the heating process of Process 4, resulting in pattern collapse. In addition, in the case where a post-development exposure process is set, it is preferable to implement the preheating process after exposure in the post-development exposure process and before heating in the heating process of Process 4.

[0156] The heating through the preheating process (hereinafter, also referred to as "intermediate baking") can also be implemented after the exposure process and before the development process. In addition, intermediate baking can also be implemented after the development process and before the heating process. Among these, in terms of suppressing development residues while suppressing melting of the coating film for good patterning, it is preferable to implement intermediate baking after the exposure process and before the development process.

[0157] An intermediate baking can be performed using a heating device such as an oven or a hot plate. Regarding the intermediate baking conditions, the heating temperature is preferably higher than that of pre-baking and lower than that of post-baking, for example, 110°C to 180°C. For example, in the case of performing heat treatment on a hot plate, the heating time is 1 minute to 20 minutes, and in the case of performing heat treatment in an oven, the heating time is 3 minutes to 40 minutes.

[0158] <Display device>

[0159] The display device of the present invention includes a hardened film formed using this composition. By forming a hardened film using this composition, a hardened film showing excellent bending resistance can be obtained. Therefore, this composition is particularly preferably a composition for forming a planarization film for an organic EL element, that is, a composition for forming a planarization film for forming an insulating layer (i.e., a planarization film) covering the step difference of a TFT circuit or wiring formed on a substrate. As a display device, for example, a liquid crystal display device or an organic EL display device can be cited.

[0160] The heat resistance and bend resistance of the cured film formed using this composition are excellent, and thus it is preferably used as a structural material for flexible displays. Examples of flexible displays include foldable displays that can be folded, bendable displays that can be turned back or bent, and rollable displays that can be wound. In addition, a structure in which extraction wiring is bent to the back of the image display unit corresponding to narrow bezel formation is sometimes employed, but for a structure having a bent portion, the cured film formed using this composition can also be applied.

[0161] According to the present disclosure described in detail above, the following means can be provided.

[0162] <Means 1> A photosensitive composition containing a polymer component and a quinone diazide compound. In the photosensitive composition, the polymer component includes a polymer (A) having a first structural unit and a second structural unit. The first structural unit has a cyclic ether structure in the main chain 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, and the polymer (A) is contained in an amount of 25% by mass or more based on the total amount of the polymer component.

[0163] <Means 2> The photosensitive composition according to <Means 1>, wherein the first structural unit is represented by the formula (1).

[0164] <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 carboxyl group, a structural unit having a sulfonic acid group, and a structural unit having a phenolic hydroxyl group.

[0165] <Means 4> The photosensitive composition according to <Means 3>, wherein the polymer (A) contains at least one selected from the group consisting of a structural unit derived from maleimide, a structural unit having a carboxyl group, and a structural unit having a sulfonic acid group as the second structural unit.

[0166] <Means 5> The photosensitive composition according to <Means 3> or <Means 4>, wherein the polymer (A) contains a structural unit having a phenolic hydroxyl group as the second structural unit.

[0167] <Means 6> The photosensitive composition according to any one of <Means 1> to <Means 5>, wherein the polymer (A) further contains a third structural unit having an oxiranyl group or an oxetanyl group.

[0168] <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.

[0169] <Means 8> The photosensitive composition according to any one of <Means 1> to <Means 7> further contains a thermal crosslinking agent.

[0170] <Means 9> The photosensitive composition according to <Means 8>, wherein the thermal crosslinking agent contains a compound having a group represented by -CH2-OR 4 (wherein, R 4 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or a thermally detachable group).

[0171] <Means 10> The photosensitive composition according to any one of <Means 1> to <Means 9> further contains a thermal acid generator.

[0172] <Means 11> The photosensitive composition according to any one of <Means 1> to <Means 10> is used for forming a planarizing film, an interlayer insulating film or a damascene material.

[0173] <Means 12> The photosensitive composition according to <Means 11> is used for an organic EL element.

[0174] <Means 13> A cured film formed from the photosensitive composition according to any one of <Means 1> to <Means 10>.

[0175] <Means 14> The cured film according to <Means 13>, which is a planarizing film, an interlayer insulating film or a damascene material.

[0176] <Means 15> A method for manufacturing a cured film, comprising:

[0177] a film forming step of forming a coating film using the photosensitive composition according to any one of <Means 1> to <Means 10>; an exposure step of exposing at least a part of the coating film formed by the film forming step; a developing step of developing the coating film after exposure by the exposure step; and a heating step of heating the coating film developed by the developing step.

[0178] <Means 16> The method for manufacturing a cured film according to <Means 15> further includes a step of exposing the coating film after development by the developing step and before heating by the heating step.

[0179] <Means 17> The method for manufacturing a cured film according to <Means 15> or <Means 16> further includes the following step: heating a coating film after development in the development step and before heating in the heating step at a temperature lower than the heating temperature in the heating step.

[0180] <Means 18> A display device includes the cured film according to <Means 13> or <Means 14>.

[0181] [Examples]

[0182] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in the examples and comparative examples are based on mass unless otherwise specified.

[0183] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)]

[0184] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer are measured by the following method.

[0185] · Measurement method: Gel permeation chromatography (GPC) method

[0186] · Apparatus: GPC-101 of Showa Denko KK

[0187] · GPC column: Combining GPC-KF-801, GPC-KF-802, GPC-KF-803 and GPC-KF-804 of Shimadzu GLC Co., Ltd.

[0188] · Mobile phase: Tetrahydrofuran

[0189] · Column temperature: 40 °C

[0190] · Flow rate: 1.0 mL / minute

[0191] · Sample concentration: 1.0 mass%

[0192] · Sample injection volume: 100 μL

[0193] · Detector: Differential refractometer

[0194] · Standard substance: Monodisperse polystyrene

[0195] [Monomer]

[0196] The abbreviations of the monomers used in the synthesis of the polymer are as follows.

[0197] [Monomer providing the first structural unit]

[0198] AOMA: Methyl 2-(allyloxymethyl)acrylate

[0199] Monomer for Providing Second Structural Unit

[0200] MI: Maleimide

[0201] MA: Methacrylic Acid

[0202] 4IPP: 4-Isopropenylphenol

[0203] HPMA: 4-Hydroxyphenyl Methacrylate

[0204] Monomer for Providing Third Structural Unit

[0205] ECHMA: Cyclohexylmethyl 3,4-Epoxy Methacrylate

[0206] GMA: Glycidyl Methacrylate

[0207] OXMA: (3-Ethyloxetan-3-yl)methyl Methacrylate

[0208] Monomer for Providing Fourth Structural Unit

[0209] MMA: Methyl Methacrylate

[0210] ST: Styrene

[0211] CHMI: N-Cyclohexylmaleimide

[0212] PMI: N-Phenylmaleimide

[0213] Monomer for Providing Other Structural Units

[0214] DOXA: (2-Methyl-2-ethyl-1,3-dioxolan-4-yl)methyl Acrylate

[0215] MPTES: 3-Methacryloxypropyltriethoxysilane

[0216] <Synthesis of Polymer (A)>

[0217] [Synthesis Example 1] Synthesis of Polymer (A-1)

[0218] Into a flask including a cooling tube and a stirrer, 10 parts of 2,2'-azobis(2-methylpropionitrile) and 200 parts of diethylene glycol methyl ether were charged. Subsequently, 10 parts of methyl 2-(allyloxymethyl)acrylate, 10 parts of maleimide, 50 parts of cyclohexylmethyl 3,4-epoxycyclohexene-1-carboxylate, 10 parts of 4-isopropenylphenol, and 20 parts of methyl methacrylate were charged. After purging with nitrogen, while gently stirring, the temperature of the solution was raised to 80°C and maintained at that temperature for 5 hours, thereby obtaining a polymer solution containing polymer (A-1). The solid content concentration of the 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.

[0219] [Synthesis Examples 2 to 13, Comparative Synthesis Examples 2 to 4] Synthesis of Polymer (A-2) to Polymer (A-13), Polymer (CA-2) to Polymer (CA-4)

[0220] Using the components of the types and blending amounts (parts by mass) shown in Table 1, polymer solutions each containing a polymer having the same solid content concentration, weight average molecular weight, and molecular weight distribution as polymer (A-1) were obtained in the same manner as in Synthesis Example 1, except for the above.

[0221] [Table 1]

[0222]

[0223] [Comparative Synthesis Example 1] Synthesis of Polymer (CA-1)

[0224] Under a dry nitrogen stream, 30 parts by mass of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved in 500 g of N-methyl-2-pyrrolidone (NMP). To this, 26.7 parts by mass of 3,3',4,4'-oxydiphthalic dianhydride and 0.9 part by mass of 4-aminophenol were added, and the reaction was carried out at 40°C for 6 hours. Subsequently, NMP was added to the obtained polyamic acid solution, and 1.8 molar equivalents each of pyridine and acetic anhydride were added with respect to the carboxyl groups derived from the tetracarboxylic dianhydride of the polyamic acid, and 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. Subsequently, the obtained polymer solution was poured into a large excess of methanol to precipitate the reaction product. The precipitate was washed with methanol and vacuum-dried at 80°C, thereby obtaining a polyimide (designated as "polymer (CA-1)").

[0225] <Preparation of Photosensitive Composition>

[0226] The following shows the components used in the preparation of the photosensitive composition.

[0227] 《Polymer Component》

[0228] A-1 to A-13: Polymers (A-1) to (A-13) synthesized in Synthesis Examples 1 to 13

[0229] CA-1 to CA-4: Polymers (CA-1) to (CA-4) synthesized in Comparative Synthesis Examples 1 to 4

[0230] 《Quinonediazide Compound》

[0231] B-1: Condensate of 4,4'-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bisphenol (1.0 mol) and 1,2-naphthoquinonediazide-5-sulfonyl chloride (2.0 mol)

[0232] B-2: Condensate of 1,1,1-tris(p-hydroxyphenyl)ethane (1.0 mol) and 1,2-naphthoquinonediazide-5-sulfonyl chloride (2.0 mol)

[0233] 《Thermal Crosslinking Agent》

[0234] C-1: 4,4'-[1-[4-[1-(4-hydroxy-3,5-bis(methoxymethyl)phenyl)-1-methylethyl]phenyl]ethylidene]-bis[2,6-bis(methoxymethyl)phenol]

[0235] C-2: 3,4-Epoxycyclohexylmethyl (3,4-epoxy)cyclohexanecarboxylate

[0236] 《Thermal Acid Generator》

[0237] D-1: Benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate

[0238] [Example 1]

[0239] To the polymer solution containing polymer (A-1) obtained in Synthesis Example 1, 20 parts of quinonediazide compound (B-1), 10 parts of thermal crosslinking agent (C-1), and 1 part of thermal acid generator (D-1) were mixed with respect to the amount equivalent to 100 parts (solid content) of polymer (A-1). 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 solid content concentration was 20% by mass. Subsequently, filtration was performed using a membrane filter with a pore size of 0.2 μm to prepare a photosensitive composition (S-1).

[0240] [Examples 2 to 17, Comparative Examples 1 to 4]

[0241] Using the components of the types and blending amounts (parts by mass) shown in Table 2, except for this, the photosensitive compositions of Examples 2 to 17 and Comparative Examples 1 to 4 were respectively prepared by the same method as in Example 1.

[0242] [Table 2]

[0243]

[0244] <Evaluation>

[0245] Using the photosensitive compositions of Examples 1 to 17 and Comparative Examples 1 to 4, the following items were evaluated by the method described below. The evaluation results are shown in Table 3.

[0246] [Sensitivity]

[0247] Using a spinner, the photosensitive composition was coated on a silicon substrate that had been subjected to HMDS treatment at 60°C for 60 seconds, and then pre-baked on a hot plate at 100°C for 2 minutes to form a coating film with an average film thickness of 3.0 μm. Interposing a pattern mask having a line and space pattern with a width of 10 μm, the coating film was irradiated with a specified amount of ultraviolet light using a mercury lamp. Subsequently, using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide as a developer, after developing for 60 seconds at 25°C, it was washed with ultrapure water for 1 minute by running water. 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 sensitivity was evaluated based on the minimum exposure amount.

[0248] [Flexural resistance]

[0249] Using a spin coater, the photosensitive composition was coated on a polyimide film substrate, and then the pressure to be reached from the photosensitive composition on the substrate was set to 100 Pa, and the solvent was removed under vacuum, and then pre-baked at 100°C for 2 minutes to form a coating film. Subsequently, using a developer (2.38 mass% aqueous solution of tetramethylammonium hydroxide), after developing for 60 seconds at 25°C, it was washed with ultrapure water for 1 minute by running water. For the obtained coating film, using a proximity exposure machine (“MA-1200” (ghi-ray mixture) manufactured by Canon Inc.), after irradiating the entire surface of the substrate with light of 3000 J / m 2 and then heating in a clean oven purged with nitrogen at 250°C for 1 hour, a hardened film with an average film thickness of 3.0 μm was formed on the substrate.

[0250] The substrate with the cured film is cut out to a size of 50 mm in length × 50 mm in width. Next, with the surface on which the cured film is formed facing outward, the substrate with the cured film is held in a bent state for 10 minutes with the polyimide film substrates in contact with each other. Ten minutes after bending, the bent substrate with the cured film is opened, and the bent portion of the surface of the cured film is observed using an optical microscope, and the bending resistance (flexural resistance) is evaluated based on the appearance change. Regarding the evaluation criteria, the case where there are no cracks in the cured film is set as "excellent (◎)", the case where there are cracks in a part of the cured film is set as "good (○)", and the case where there are cracks throughout the cured film is set as "unacceptable (×)".

[0251] [Heat resistance]

[0252] Using a spinner, the photosensitive composition is coated on a silicon substrate, and then pre-baked on a hot plate at 100 °C for 2 minutes to form a coating film with a film thickness of 3.0 μm. Subsequently, using a proximity exposure machine ("MA-1200" manufactured by Canon Inc. (ghi-ray mixture)), after irradiating the entire surface of the substrate with light of 3000 J / m 2 the silicon substrate is heated in a clean oven replaced with nitrogen at 250 °C for 60 minutes to form a cured film. The 5% thermogravimetric reduction temperature of the formed cured film is measured in air using a differential thermal / thermogravimetric simultaneous measurement device ("TG / DTA220U" manufactured by Hitachi High-Tech Science Corporation). The case where the 5% weight reduction temperature is 320 °C or higher is set as "excellent (◎)", the case where it is 300 °C or higher and less than 320 °C is set as "good (○)", the case where it is 280 °C or higher and less than 300 °C is set as "acceptable (△)", and the case where it is less than 280 °C is set as "unacceptable (×)", and the heat resistance is evaluated.

[0253] [Reprocessability]

[0254] Using a spinner, the photosensitive composition is coated on a silicon substrate that has been subjected to HMDS treatment at 60 °C for 60 seconds, and then pre-baked on a hot plate at 100 °C for 2 minutes to form a coating film with an average film thickness of 3.0 μm. After immersing the substrate in propylene glycol monomethyl ether acetate at 23 °C, the presence or absence of coating film residue on the substrate is observed. The case where the immersion time when the coating film residue disappears is less than 2 minutes is set as "excellent (◎)", the case where it is 2 minutes or more and less than 3 minutes is set as "good (○)", and the case where it is 5 minutes or more is set as "unacceptable (×)".

[0255] [Resistance to melting during post-baking]

[0256] Using a spinner, a photosensitive composition was coated on a silicon substrate that had been subjected to HMDS treatment at 60°C for 60 seconds, and then pre-baked on a hot plate at 100°C for 2 minutes to form a coating film with an average film thickness of 3.0 μm. A pattern mask separating lines and spaces with a width of 10 μm was used, and the coating film was irradiated with a specified amount of ultraviolet light using a mercury lamp. Subsequently, a 2.38 mass% aqueous solution of tetramethylammonium hydroxide was used as a developer, and development was carried out at 25°C for 60 seconds, followed by rinsing with ultrapure water for 1 minute. The line width of the line-and-space pattern obtained at this time was designated as X1. Subsequently, using a proximity exposure machine ("MA-1200" manufactured by Canon (ghi-ray mixture)), after irradiating the entire substrate surface with light of 3000 J / m 2 the silicon substrate was heated in a clean oven at 140°C for 15 minutes. Furthermore, a hardened film was formed by heating the silicon substrate at 230°C for 30 minutes. The line width of the line-and-space pattern obtained at this time was designated as X2. The case where the value obtained by subtracting X2 from X1 (=X1 - X2) was less than 0.1 μm was designated as "excellent (◎)", the case where it was 0.1 μm or more and less than 0.2 μm was designated as "good (○)", and the case where it was 0.2 μm or more was designated as "inferior (×)".

[0257] [Table 3]

[0258]

[0259] As shown in Table 3, as practical properties, the sensitivities, flexural resistances, heat resistances, reprocessabilities, and melt resistances during post-baking of the photosensitive compositions of Examples 1 to 17 were all evaluated as good, achieving a balance of various properties. In contrast, the reprocessability of the hardened film formed from the photosensitive composition of Comparative Example 1 was poor. In addition, the flexural resistances and heat resistances of the hardened films formed from the photosensitive compositions of Comparative Examples 2 to 4 were worse than those of Examples 1 to 17.

Claims

1. A photosensitive composition containing a polymer component and a quinonediazide compound, in the photosensitive composition, the polymer component includes a polymer (A) having a first structural unit and a second structural unit, the first structural unit has a cyclic ether structure in the main chain 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, containing 25% by mass or more of the polymer (A) relative to the total amount of the polymer component.

2. The photosensitive composition according to claim 1, wherein the first structural unit is represented by the following formula (1), In formula (1), R1 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms; R2 is a hydrogen atom or -COOR3; R3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms; n is 0 or 1.

3. 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 carboxyl group, a structural unit having a sulfonic acid group, and a structural unit having a phenolic hydroxyl group.

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

5. The photosensitive composition according to claim 3, wherein the polymer (A) contains 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 contains a third structural unit having an oxiranyl group or an oxetanyl group.

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

8. The photosensitive composition according to claim 1, further containing a thermal crosslinking agent.

9. The photosensitive composition according to claim 8, wherein the thermal crosslinking agent contains a compound having a group represented by -CH2-OR4, wherein R4 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally dissociable group.

10. The photosensitive composition according to claim 1, further containing a thermal acid generator.

11. The photosensitive composition according to any one of claims 1 to 10, for forming a planarization film, an interlayer insulating film, or a damascene material.

12. The photosensitive composition according to claim 11, for an organic electroluminescent element.

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 planarization film, an interlayer insulating film, or a damascene material.

15. A method for manufacturing a cured film, comprising: a film formation 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 part of the coating film formed by the film formation step; A developing step of developing the coated film after exposure by the exposure step; and a heating step of heating the coated film developed by the developing step.

16. The method for manufacturing a hardened film according to claim 15, further comprising the step of: exposing the coated film after development by the developing step and before heating by the heating step.

17. The method for manufacturing a hardened film according to claim 15, further comprising the step of: heating the coated film after development by the developing step and before heating by the heating step at a temperature lower than the heating temperature in the heating step.

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

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