Polyimide precursor, method for producing a polyimide precursor, photosensitive composition, and method for producing a patterned cured film

Abstract

To provide a novel polyimide precursor and the like. 【Solution Means】A polyimide precursor comprising a structural unit represented by formula (1). JPEG2026167599000044.jpg44149[In the formula, X 1 represents a tetravalent organic group, Y 1 represents an (n+2)-valent organic group, Z represents a monovalent organic group containing a photosensitive group, L 1 and L 2 each independently represent an oxy group or an amino group, L 3 represents an (m+1)-valent amino group, R 1 and R 2 each independently represent a hydrogen atom or a monovalent organic group, m represents 1 or 2, and n represents 1 or 2.]

Description

[Technical Field]

[0001] This disclosure relates to a polyimide precursor, a method for producing a polyimide precursor, a photosensitive composition, and a method for producing a patterned cured film. [Background technology]

[0002] A photosensitive composition containing a photosensitive polyimide precursor is sometimes used to form protective films and insulating films for semiconductor devices. As a photosensitive polyimide precursor, a polyamic acid in which a photosensitive group is introduced to the carboxyl group via an ester bond is widely used (for example, Patent Documents 1-3). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2005-049504 [Patent Document 2] Japanese Patent Publication No. 2020-122875 [Patent Document 3] Japanese Patent Publication No. 2021-196482 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] One aspect of this disclosure aims to provide novel polyimide precursors and methods for producing polyimide precursors. Another aspect of this disclosure aims to provide photosensitive compositions using such polyimide precursors and methods for producing patterned cured films. [Means for solving the problem]

[0005] This disclosure includes the following aspects: [1] A polyimide precursor containing a structural unit represented by the following formula (1). [ka] [In the formula, X 1 represents a tetravalent organic group, Y 1 represents an (n+2)-valent organic group, Z represents a monovalent organic group containing a photosensitive group, L 1 and L 2 each independently represent an oxy group or an amino group, L 3 represents an (m+1)-valent amino group, R 1 and R 2 each independently represent a hydrogen atom or a monovalent organic group, m represents 1 or 2, and n represents 1 or 2.] [2] The polyimide precursor according to [1], wherein Y 1 comprises a structure represented by the following formula (2a) or (2b).

Chemical Formula

Chemical Formula

Chemical Formula

[11] The photosensitive composition according to

[10] , further comprising a photopolymerization initiator.

[12] The photosensitive composition according to

[10] or

[11] , further comprising a crosslinking agent.

[13] A photosensitive composition containing a polyimide precursor described in any of [1] to [6] and an organic solvent is applied to a substrate, and the organic solvent is removed from the photosensitive composition to form a photosensitive layer. The photosensitive layer is exposed and developed to form a resist pattern, The photosensitive layer after the resist pattern is formed is subjected to heat treatment to form a pattern-cured film containing polyimide, A method for manufacturing a patterned cured film, including the method described above. [Effects of the Invention]

[0006] According to one aspect of this disclosure, novel polyimide precursors and methods for producing polyimide precursors can be provided. According to another aspect of this disclosure, photosensitive compositions using such polyimide precursors and methods for producing patterned cured films can be provided. [Modes for carrying out the invention]

[0007] The present disclosure is described in detail below. However, the present disclosure is not limited to the following embodiments.

[0008] In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. Furthermore, in numerical ranges described in stages within this specification, the upper or lower limit of one stage of the numerical range may be replaced by the upper or lower limit of another stage of the numerical range. In numerical ranges described within this specification, the upper or lower limit of that numerical range may be replaced by the values ​​shown in the examples. When referring to the amount of each component in a composition within this specification, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition. In this specification, "solid content" refers to the non-volatile content of a photosensitive composition excluding volatile substances (water, solvents, etc.), and includes components that remain without volatilization when the photosensitive composition is dried, as well as components that are liquid, syrup-like, and waxy at room temperature around 25°C. In this specification, "(meth)acrylic" means acrylic or the corresponding methacrylic. In this specification, the asterisk (*) in chemical structure formulas indicates a bond.

[0009] [Polyimide precursor] A polyimide precursor according to one embodiment of the present disclosure includes a structural unit represented by the following formula (1). [ka]

[0010] In formula (1), X 1 This indicates a tetravalent organic group, Y 1 indicates an (n+2)-valent organic group, Z indicates a monovalent organic group containing a photosensitive group, and L 1 and L 2 Each independently represents either an oxy group or an amino group, L 3 indicates an (m+1) valent amino group, R 1 and R 2 Each independently represents a hydrogen atom or a monovalent organic group, m represents 1 or 2, and n represents 1 or 2. When a polyimide precursor has multiple structural units represented by formula (1) in the same molecule, X 1 , Y 1 Z, L 1 , L 2 , L 3 , R 1 , R 2 m and n may be the same or different structural units.

[0011] The polyimide precursor according to this embodiment can be obtained, for example, by reacting a tetracarboxylic acid derivative with at least one amine selected from triamines and tetraamines, and further by introducing a photosensitive group to the unreacted amino group of the amine (the amino group that did not participate in the reaction with the tetracarboxylic acid derivative). In this case, of the structural unit represented by formula (1), the part represented by formula (1a) below corresponds to the part derived from the tetracarboxylic acid derivative, and the part represented by formula (1b) below corresponds to the part derived from the specific amine (the unreacted amino group to which a photosensitive group has been introduced). The method for producing the polyimide precursor will be described in detail later. [ka] In the formula, X 1 , Y 1 Z, L 1 , L 2 , R 1 , R 2 m and n are X in equation (1), respectively. 1 , Y 1 Z, L 1 , L 2 , R 1 , R 2 This indicates the same definition as m and n.

[0012] Furthermore, when conventional polyimide precursors, in which a photosensitive group is introduced to the carboxyl group of a polyamic acid via an ester bond, are used together with a crosslinking agent, a site where the photosensitive group and the crosslinking agent are bonded may be formed. During imidation, the cleavage of the ester bond may produce alcohols (primary alcohols, secondary alcohols, etc.) containing the site where the photosensitive group and the crosslinking agent are bonded. If such alcohols remain in the imide resin, it can cause deterioration of the low dielectric properties. In contrast, the polyimide precursor according to this embodiment has a structure in which a photosensitive group is introduced to the amino group of the main skeleton, so the bond between the amino group and the photosensitive group is less likely to cleave. Therefore, even when used with a crosslinking agent, it is less likely to generate substances that worsen the low dielectric properties, and a polyimide resin with excellent low dielectric properties can be obtained. Furthermore, the part in which the photosensitive group is introduced to the amino group is less likely to detach even after imidization and can be crosslinked with other components via the crosslinking agent. Therefore, according to the polyimide precursor according to this embodiment, the obtained polyimide resin can be given excellent properties such as a high glass transition temperature (Tg).

[0013] Furthermore, in the case of the conventional polyimide precursors mentioned above, the types of photosensitive groups that can be introduced to the carboxyl group of the polyamic acid are limited. In contrast, the polyimide precursor according to this embodiment offers greater freedom in selecting the photosensitive group that can be introduced into the amino group of the main skeleton. Therefore, by appropriately selecting the type of photosensitive group, properties such as alkali solubility (alkali developability) and organic solvent solubility (organic solvent developability) can be imparted to the polyimide precursor. For example, by introducing a photosensitive group having a terminal carboxylic acid structure, a polyimide precursor soluble in alkalis such as tetramethylammonium hydroxide (TMAH) solution and sodium carbonate aqueous solution can be obtained. Furthermore, by introducing an ester-modified functional group, a polyimide precursor soluble in organic solvents such as cyclopentanone and propylene glycol monomethyl ether acetate (PGMEA, 2-methoxy-1-methylethyl acetate) can be obtained.

[0014] X in equation (1) 1 The tetravalent organic group indicated by may include a substituted aromatic group, a substituted cyclic aliphatic group, or a combination thereof.

[0015] X 1 For example, it may include a structure represented by the following formula (4). In this case, the two benzene rings in formula (4) may each be unsubstituted or may have substituents. [ka] [In the formula, L 5 represents a divalent linking group, and q represents either 0 or 1.

[0016] When q in equation (4) is 0, the structure is one in which two benzene rings are directly bonded. Also, when q is 1, L 5 Examples of divalent linking groups represented by include divalent hydrocarbon groups (including alkylene groups, cycloalkylene groups, and arylene groups), carbonyl groups, sulfonyl groups, thio groups, carbonyloxy groups, oxy groups, amide groups, or combinations of two or more of these divalent groups.

[0017] Examples of tetravalent organic groups containing the structure represented by formula (4) include the tetravalent organic groups represented by the following formulas (4-1) to (4-6). [ka]

[0018] X in equation (1) 1 -C(=O)-L 1 -R 1 and C(=O)-L 2 -R 2 In L 1 and L 2 Each independently represents either an oxy group or an amino group, R 1 and R 2 Each of these independently represents a hydrogen atom or a monovalent organic group. During imidation, -C(=O)-L 1 -R 1 and C(=O)-L 2 -R 2 Then, through a reaction (cyclization) with the amino group (-NH-) in the main skeleton, an imide ring is formed. -C(=O)-L 1 -R 1 and C(=O)-L 2 -R 2 This may include a carboxylic acid structure, an ester structure, or an amide structure.

[0019] R 1 and R 2 is a monovalent organic group, the number of carbon atoms of the monovalent organic group may be 1 to 20, 1 to 10, or 1 to 5. In addition, the molecular weight of the monovalent organic group may be 15 to 500, 15 to 400, or 15 to 300. Examples of the monovalent organic group include monovalent organic groups represented by the following formulas (R-1) to (R-7). [Chemical Formula] [In the formula, * represents a bond to L 1 or L 2 .]

[0020] The (n+2)-valent organic group represented by Y 1 in formula (1) may include an optionally substituted aromatic group, an optionally substituted cycloaliphatic group, or a combination of two or more thereof.

[0021] Y 1 may include, for example, a trivalent organic group represented by the following formula (2a) (when n is 1), or a tetravalent organic group represented by the following formula (2b) (when n is 2). [Chemical Formula] [In the formula, L 4 represents a divalent linking group, and p represents 0 or 1.]

[0022] The two benzene rings in formula (2a) and the two benzene rings in formula (2b) may each be unsubstituted or may have a substituent.

[0023] When p is 0, the structure is such that the two benzene rings in formula (2a) or formula (2b) are directly bonded. When p is 1, examples of the divalent linking group represented by L 4 include divalent hydrocarbon groups (including alkylene groups, cycloalkylene groups and arylene groups), carbonyl groups, sulfonyl groups, thio groups, carbonyloxy groups, oxy groups, amide groups, or divalent groups that are combinations of two or more of these.

[0024] Examples of trivalent organic groups represented by formula (2a) include the trivalent organic group represented by formula (2a-1) below. Examples of tetravalent organic groups represented by formula (2b) include the tetravalent organic groups represented by formulas (2b-1) to (2b-4) below. [ka]

[0025] Also, Y 1 This may be a trivalent organic group represented by the following formula (2c). [ka]

[0026] Y in equation (1) 1 L 3 A monovalent organic group Z containing a photosensitive group is bonded via an (m+1) valent amino group shown by . When m is 1, L 3 is a divalent amino group (-NH-), and when m is 2, L 3 is a trivalent amino group (-N<). Photosensitive groups included in Z include acryloyl group, methacryloyl group, vinyl group, styryl group, maleimide group, etc., and among these, at least one photosensitive group selected from the group consisting of acryloyl group, methacryloyl group, vinyl group, and styryl group is preferred. Examples of Z include monovalent organic groups represented by the following formulas (Z-1) to (Z-8). [ka]

[0027] The polyimide precursor according to this embodiment may include, in addition to the structural unit represented by formula (1) above, a structural unit represented by the following formula (3). [ka] [where, X 1 This indicates a tetravalent organic group, Y2 represents a divalent organic group having no photosensitive group, and L 1 and L 2 each independently represent an oxy group or an amino group, and R 1 and R 2 each independently represent a hydrogen atom or a monovalent organic group.]

[0028] X in formula (3) 1 , L 1 , L 2 , R 1 and R 2 are each the same as X in formula (1) 1 , L 1 , L 2 , R 1 and R 2 respectively.

[0029] Y 2 may include a residue obtained by removing two amino groups from a diamine having an aromatic ring and / or an alicyclic ring. When the residue contains two or more aromatic rings and / or alicyclic rings, these rings may be directly bonded to each other, or may be bonded via a linking group such as an alkylene group or an oxy group (-O-). Examples of Y 2 include divalent organic groups represented by the following formulas (Y2-1) to (Y2-6). [Chemical Formula]

[0030] When the polyimide precursor contains a structural unit represented by formula (1) (a structural unit containing a photosensitive amine moiety) and a structural unit represented by formula (3) (a structural unit not containing a non-photosensitive amine moiety), by adjusting the content ratio of these structural units or the content ratio of Y 1 and Y 2 , desired properties can be imparted to the polyimide precursor, and further to the polyimide resin after imidization. Of the total of Y 1 and Y 2 contained in the polyimide precursor, the proportion of Y 1 (Y 1 / (Y 1 +Y2 The ratio of (mol%) × 100 (mol%) may be 0.1 to 100 mol%, 0.1 to 50 mol%, or 0.1 to 20 mol%. From the viewpoint of sensitivity, this ratio may be 0.1 mol% or more, 3 mol% or more, or 5 mol% or more. Also, from the viewpoint of low dielectric properties, this ratio may be 100 mol% or less, 50 mol% or less, or 20 mol% or less. This ratio can be calculated from the type and proportion of amine used as raw material.

[0031] The weight-average molecular weight (Mw) of the polyimide precursor is not particularly limited. From the viewpoint of the mechanical properties of the cured product, Mw may be, for example, 5,000 to 200,000, 8,000 to 100,000, or 9,000 to 50,000.

[0032] The number-average molecular weight (Mn) of the polyimide precursor is not particularly limited. From the viewpoint of viscosity, Mn may be, for example, 2000-50000, 3000-30000, or 4000-20000.

[0033] The degree of dispersion (Mw / Mn) of the polyimide precursor is not particularly limited. From the viewpoint of viscosity and the mechanical properties of the cured product, Mw / Mn may be, for example, 1.0 to 10.0, 1.0 to 5.0, or 1.0 to 3.0.

[0034] The weight-average molecular weight (Mw), number-average molecular weight (Mn), and dispersion (Mw / Mn) used herein were measured by gel permeation chromatography (GPC) and converted to values ​​using standard polystyrene as the standard sample.

[0035] [Method for producing polyimide precursors: First method] Regarding the method for producing a polyimide precursor in this disclosure, one embodiment of the first method is: In the presence of N,N'-dicyclohexylcarbodiimide (DCC), a compound represented by the following formula (5) is reacted with an amine containing at least one selected from the group consisting of triamines and tetraamines to obtain a compound containing a structural unit represented by the following formula (6). A compound containing a structural unit represented by the following formula (6) is reacted with a compound having a reactive group for an amino group and a photosensitive group to obtain a polyimide precursor containing a structural unit represented by the following formula (1), Includes. [ka] [ka] [ka] [where, X 1 This indicates a tetravalent organic group, Y 1 indicates an (n+2)-valent organic group, Z indicates a monovalent organic group containing a photosensitive group, and L 1 and L 2 Each independently represents either an oxy group or an amino group, L 3 indicates an (m+1) valent amino group, R 1 and R 2 Each of these independently represents a hydrogen atom or a monovalent organic group, where m represents 1 or 2, and n represents 1 or 2.

[0036] The compound represented by formula (5) is, for example, a tetracarboxylic dianhydride and a hydroxy compound (R 1 OH and R 2 It can be obtained by reaction with OH). In this embodiment, a compound represented by formula (5) that has been synthesized in advance may be obtained and used in the first production method. Alternatively, the first production method may further include reacting a tetracarboxylic dianhydride with a hydroxy compound to obtain a compound represented by formula (5).

[0037] Examples of tetracarboxylic dianhydrides include 4,4'-oxydiphthalic anhydride (ODPA), 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)1,4-phenylene (TAHQ), p-biphenylenebis(trimellitic acid monoester anhydride) (BP-TME), and bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-carboxylate) (TMPBP-TME).

[0038] Examples of hydroxy compounds include 2-propanol (isopropanol), ethyl 3-hydroxy-2-methylpropionate, 2-(2-hexyloxyethoxy)ethanol, 2-[2-(2-butoxyethoxy)ethoxy]ethanol, 4-methoxyphenylmethanol (p-methoxybenzyl alcohol), 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 3-methoxy-1-butanol, hydroxyethyl methacrylate, and long-chain acrylates.

[0039] The reaction between tetracarboxylic dianhydride and hydroxy compounds may be carried out in the presence of a catalyst. Examples of catalysts include pyridine, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), DBN (1,5-diazabicyclo[4.3.0]non-5-ene), 4-DMAP (4-dimethylaminopyridine), triethylamine, N,N-diisopropylethylamine, and 1,4-diazabicyclo[2.2.2]octane. The amount of catalyst used may be, for example, 1.5 to 2.5 equivalents relative to the tetracarboxylic dianhydride. The reaction conditions can be appropriately selected, for example, a reaction temperature of 0 to 80°C and a reaction time of 1 to 2 hours.

[0040] The reaction between the tetracarboxylic dianhydride and the hydroxy compound may be carried out in a solvent. The solvent is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride, the hydroxy compound, and the compound represented by formula (5) that will be produced. Examples of such solvents include aprotic solvents such as N-methyl-2-pyrrolidone (NMP), phenolic solvents, ethers, and glycolic solvents. If the solvent is capable of dissolving the compound represented by formula (5), amines, N,N'-dicyclohexylcarbodiimide, compounds containing the structural unit represented by formula (6), compounds having a reactive group for an amino group and a photosensitive group, and polyimide precursors containing the structural unit represented by formula (1), the reaction solution after each reaction may be used directly for the next reaction.

[0041] N,N'-dicyclohexylcarbodiimide (DCC) has the function of activating the carboxylic acid group (-COOH) of the compound represented by formula (5). The amount of DCC used may be, for example, 1.80 to 2.20 moles, 1.90 to 2.10 moles, or 1.95 to 2.05 moles per mole of the compound represented by formula (5).

[0042] Among the amines used in reactions with the compound represented by formula (5), examples of triamines include 2,4,4'-triaminodiphenyl ether (TADE), melamine, 2,4-diamino-6-diallylamino-1,3,5-triazine, 2-N-butyl-1,3,5-triazine-2,4,6-triamine, and 1,3,5-tris(4-aminophenoxy)benzene. Examples of tetraamines include 3,3'-diaminobenzidine (DAB), 3,3',4,4'-tetraaminodiphenyl ether (TAB-E), bis(3,4-diaminophenyl)methanone (TABP), and 3,3',4,4'-tetraaminodiphenylsulfone (TAB-S).

[0043] Furthermore, when producing a polyimide precursor containing the structural unit represented by formula (1) and the structural unit represented by formula (3), the amine subjected to the reaction with the compound represented by formula (5) further includes a diamine in addition to at least one selected from the group consisting of triamines and tetraamines. Examples of diamines include 2,2'-dimethylbenzidine (m-Tolidine, corresponding to formula (Y2-1)), 4,4'-diaminodiphenyl ether (4,4'-ODA, corresponding to formula (Y2-2)), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP, corresponding to formula (Y2-3)), 1,3-bis(4-aminophenoxy)benzene (TPE-R, corresponding to formula (Y2-4)), 4,4'-bis(4-aminophenoxy)biphenyl (BAPB, corresponding to formula (Y2-5)), and dimeramine (DDA, for example, Priamin 1075 (registered trademark, corresponding to formula (Y2-6), manufactured by Croda Japan Co., Ltd.)).As diamines, 4-aminophenyl 4-aminobenzoate, 2,2'-bis(trifluoromethyl)benzidine, bis(4-aminophenyl)sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-diaminobenzanilide, 3,7-diamino-2,8-dimethyldibenzothiophenesulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, neopentyl glycol bis(4-aminophenyl) ether, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 4,4'-(m-phenylenediisopropylidene)dianiline, 4,4'-(p-phenylenediisopropylidene)dianiline, 4,4'-diaminodiphenyl You may also use nylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 1,4-phenylenediamine, bis(aminomethyl)norbornane, isophoronediamine, 9,9-bis(4-aminophenyl)fluorene, 4,4'-methylenebis(cyclohexylamine), 4'-methylenebis(2-methylcyclohexylamine), 4,4'-(piperazine-1,4-diyl)dianiline, 3,3'-dihydroxybenzidine, 4,4'-diamino-[1,1'-biphenyl]-2,2'-dicarboxylic acid, 4,4'-diamino-[1,1'-biphenyl]-2,2'-disulfonic acid, O,O'-bis(2-aminopropyl)polyethylene glycol-BLOCK-polyethylene glycol-BLOCK-polyethylene glycol, 3,4'-diaminodiphenyl ether, 3,5-diaminobenzoic acid, etc.

[0044] The amount of amine used (the total amount of diamine, triamine, and tetraamine if diamine is used) can be appropriately selected depending on the compound represented by formula (5) and the type of amine. For example, the amount of amine used may be 0.8 to 1.5 moles, 0.8 to 1.2 moles, or 0.8 to 1.1 moles per mole of the compound represented by formula (5).

[0045] The mixing order of DCC, the compound represented by formula (5), and the amine is not particularly limited. For example, DCC can be added to an NMP solution containing the compound represented by formula (5), followed by the addition of the amine. DCC and the amine may be added separately in NMP solutions. The reaction conditions can be appropriately selected depending on the type of compound represented by formula (5) and the amine. The reaction temperature may be -40 to +15°C, -20 to +10°C, or -10 to +10°C from the viewpoint of controlling reactivity. The reaction time may be, for example, 1 to 3 hours, 1 to 2.5 hours, or 1 to 2 hours. Alternatively, the viscosity of the reaction solution may be measured using an E-type viscosity system, and the endpoint of the reaction may be defined as the point at which the viscosity becomes constant.

[0046] Next, a compound containing the structural unit represented by formula (6) is reacted with a compound having a reactive group for an amino group and a photosensitive group to obtain a polyimide precursor containing the structural unit represented by formula (1).

[0047] The reactive group for the amino group is not particularly limited as long as it can react with the amino group to form a bond. Examples of such reactive groups include carboxylic acid groups, acid anhydride groups, ester groups, acyl halide groups, isocyanate groups, epoxy groups, and maleimide groups. In addition, examples of photosensitive groups include the photosensitive groups exemplified in the explanation of Z in formula (1).

[0048] Examples of compounds having reactive and photosensitive groups for amino groups include allyl succinic anhydride, methacrylic anhydride, 2-isocyanatoethyl methacrylate, 2-(2-methacryloyloxyethyloxy)ethyl isocyanate, 2-isocyanatoethyl acrylate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, phthalic anhydride, methacrylate chloride, mono(2-acryloyloxyethyl) succinate, mono-2-(methacryloyloxy)ethyl phthalate, monohydroxyethyl phthalate, ω-carboxy-polycaprolactone (n≒2) monoacrylate, 6-acrylamidohexanoic acid, 4-carboxystyrene, allyl methacrylate, and 1H-imidazole-1-carboxylate 2-(methacryloyloxy)ethyl. As the compound, commercially available products such as Karenz MOI, Karenz MOI-EG, Karenz AOI, and Karenz BEI (all manufactured by Resonac Co., Ltd., trade names) may be used. The amount of the compound used can be appropriately selected depending on the amount of amino group (-NH2) of the compound having the structure represented by formula (6).

[0049] The reaction conditions for a compound containing the structural unit represented by formula (6) and a compound having a reactive group for an amino group and a photosensitive group can be appropriately selected depending on the type of compound. The reaction temperature may be, for example, -20 to +120°C, -10 to +100°C, or -10 to +80°C. The reaction time may be, for example, 0.5 to 3 hours, 0.5 to 2 hours, or 0.5 to 1 hour.

[0050] After the reaction is complete, appropriate treatments such as removal of the solvent from the reaction solution and purification (reprecipitation, etc.) are performed to obtain a polyimide precursor containing the structural unit represented by formula (1). The polyimide precursor may also be in the form of a polymer solution (coating varnish) obtained by dissolving and diluting it with a solvent.

[0051] [Method for producing polyimide precursors: Second method] Regarding the method for producing a polyimide precursor in this disclosure, one embodiment of the second method is: A compound containing a structural unit represented by the following formula (7) is obtained by reacting a tetracarboxylic dianhydride with an amine containing at least one selected from triamines and tetraamines. The method involves reacting a compound represented by the following formula (7) with a compound having a reactive group for an amino group and a photosensitive group to obtain a polyimide precursor containing a structural unit represented by the following formula (8), Includes. [ka] [ka] [where, X 1 This indicates a tetravalent organic group, Y 1 This indicates an (n+2) valent organic group, L 3 [where 'm' indicates an (m+1) valent amino group, 'Z' indicates a monovalent organic group containing a photosensitive group, 'm' indicates 1 or 2, and 'n' indicates 1 or 2.]

[0052] Examples of tetracarboxylic dianhydrides, triamines, and tetraamines used in this embodiment include the tetracarboxylic dianhydrides, triamines, and tetraamines exemplified in the description of the first manufacturing method described above. In addition, the amine may further include a diamine in addition to at least one selected from triamines and tetraamines.

[0053] The amount of amine used (or, in the case of diamines, the total amount of triamine and / or tetraamine and diamine used) can be appropriately selected depending on the type of tetracarboxylic dianhydride and amine. For example, the amount of amine used may be 0.8 to 1.5 moles, 0.8 to 1.2 moles, or 0.8 to 1.1 moles per mole of tetracarboxylic dianhydride.

[0054] The reaction between the tetracarboxylic dianhydride and the amine may be carried out in a solvent. The solvent is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride, the amine, and the compound represented by formula (7) that will be produced. Examples of such solvents include those exemplified in the description of the first manufacturing method above.

[0055] The reaction conditions for reacting tetracarboxylic dianhydride with an amine can be appropriately selected depending on the type of tetracarboxylic dianhydride and amine. The reaction temperature may be -20 to +80°C, -20 to +50°C, or -20 to +40°C from the viewpoint of molecular weight control. The reaction time may be, for example, 0.5 to 24 hours, 0.5 to 12 hours, or 0.5 to 8 hours. Alternatively, the viscosity of the reaction solution may be measured using an E-type viscosity system, and the reaction endpoint may be defined as the point at which the viscosity becomes constant.

[0056] Next, a compound represented by formula (7) is reacted with a compound having a reactive group for an amino group and a photosensitive group to obtain a polyimide precursor containing a structural unit represented by formula (8).

[0057] Examples of compounds having reactive groups and photosensitive groups for amino groups include those exemplified in the description of the first manufacturing method above. The amount of the compound used can be appropriately selected depending on the amount of amino group (-NH2) of the compound having the structure represented by formula (7).

[0058] The reaction conditions for a compound containing the structural unit represented by formula (7) and a compound having a reactive group for an amino group and a photosensitive group can be appropriately selected depending on the type of compound. The reaction temperature may be, for example, -20 to +60°C, -20 to +50°C, or -20 to +40°C. The reaction time may be, for example, 0.5 to 24 hours, 0.5 to 12 hours, or 0.5 to 6 hours.

[0059] Furthermore, the second manufacturing method may further include reacting a polyimide precursor represented by formula (8) with a compound having a reactive group for a carboxylic acid group to obtain a polyimide precursor containing a structural unit represented by the following formula (9). In this case, the obtained polyimide precursor may further contain, in addition to the structural unit represented by formula (9), a structural unit in which some or all of the two -COOH groups in formula (8) remain unreacted. [ka] [where, X 1 This indicates a tetravalent organic group, Y 1 indicates an (n+2)-valent organic group, Z indicates a monovalent organic group containing a photosensitive group, and L 1 and L 2 Each independently represents either an oxy group or an amino group, L 3 indicates an (m+1) valent amino group, R 3 and R 4 Each of these independently represents a monovalent organic group, where m represents 1 or 2, and n represents 1 or 2.

[0060] Compounds having a reactive group for a carboxylic acid group are those in formula (8) X 1 The carboxylic acid group (-COOH) attached to it is -CL 1 -R 3 Or CL 2 -R 4 There are no particular restrictions as long as it can be converted to the target -CL. 1 -R 3 Or CL 2 -R 4 It can be selected as appropriate depending on the structure. For example, by reacting a polyimide precursor containing a structural unit represented by formula (8) with N,N-dimethylformamide diethyl acetal at a predetermined temperature (e.g., 60°C), X 1 Some or all of the -COOH groups bonded to the molecule can be converted to -COOC2H5. In this reaction, N,N-dimethylformamide (DMF) may be produced as a byproduct, but DMF can be removed by reprecipitation or other means.

[0061] After the reaction is complete, appropriate treatments such as removal of the solvent from the reaction solution and purification (reprecipitation, etc.) are performed to obtain a polyimide precursor containing the structural unit represented by formula (8) and / or the structural unit represented by formula (9). The polyimide precursor may be in the form of a polymer solution (coating varnish) obtained by dissolving and diluting it with a solvent.

[0062] [Photosensitive composition] A photosensitive composition according to one embodiment of the present disclosure contains the polyimide precursor and an organic solvent. The inclusion of an organic solvent in the photosensitive composition facilitates application to a substrate and allows for the formation of a coating film of uniform thickness. The solvent may be used alone or in combination of two or more.

[0063] The organic solvent is not particularly limited as long as it can dissolve the polyimide precursor. Examples of organic solvents include N-methyl-2-pyrrolidone (NMP), 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylcaprolactam, N,N,N',N'-tetramethylurea, cyclopentanone, cyclohexanone, propylene glycol methyl ether acetate, tetrahydrofuran (THF), 2-methyltetrahydrofuran (Me-THF), diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, 2-butoxyethanol, ethylene glycol monobutyl ether acetate, and ethylene glycol monomethyl ether acetate.

[0064] The amount of organic solvent added is not particularly limited, but may be such that the solid content in the photosensitive composition is 5-60% by mass, 10-50% by mass, or 15-40% by mass.

[0065] The photosensitive composition according to this embodiment may further contain a photopolymerization initiator (also referred to as "photoinitiator"). The photopolymerization initiator is not particularly limited as long as it is a compound that initiates polymerization by irradiation with active light (ultraviolet light, etc.), but examples include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, intramolecular hydrogen abstraction type photopolymerization initiators, and oxime ester-based photopolymerization initiators.

[0066] Alkylphenone-based photopolymerization initiators are available for purchase, for example, as Omnirad 651, Omnirad 184, Omnirad 1173, Omnirad 2959, Omnirad 127, Omnirad 907, Omnirad 369, and Omnirad 379EG from IGM Resins BV. Acylphosphine oxide-based photopolymerization initiators are available for purchase, for example, as Omnirad 819 and Omnirad TPO H from IGM Resins BV. Intramolecular hydrogen abstraction type photopolymerization initiators are available for purchase, for example, as Omnirad MBF and Omnirad 754 from IGM Resins BV. Oxime ester-based photopolymerization initiators are available for purchase, for example, as Irgacure OXE-01 and Irgacure OXE-02 from BASF Japan Ltd. To accelerate the photoreaction, a titanocene-based photopolymerization initiator (e.g., Irgacure 784 from BASF Japan Ltd.) may be used in combination.

[0067] The amount of photopolymerization initiator may be 0.1 to 10.0 parts by mass, 0.5 to 8.0 parts by mass, 0.8 to 6.0 parts by mass, or 1.0 to 5.0 parts by mass per 100 parts by mass of polyimide precursor (or 100 parts by mass of the total amount of polyimide precursor and crosslinking agent if a crosslinking agent described later is used), as this facilitates excellent microprocessability.

[0068] The photosensitive composition according to this embodiment may further contain a crosslinking agent. The crosslinking agent may be a polymerizable crosslinking agent. The polymerizable group may be a photopolymerizable group or a thermopolymerizable group. Examples of polymerizable groups include (meth)acryloyl groups, allyl groups, and vinyl groups. The crosslinking agent may be a polyfunctional compound having two or more polymerizable groups. Furthermore, the crosslinking agent can crosslink not only with other crosslinking agents but also with polyimide precursors during exposure of the photosensitive layer. Furthermore, the crosslinking agent can crosslink with other polymerizable crosslinking agents during heating of the resin film after pattern formation. The crosslinking agent can be used alone or in combination of two or more types.

[0069] The photosensitive composition according to this embodiment may contain a polymerizable crosslinking agent having (meth)acryloyl groups as a crosslinking agent from the viewpoint of dielectric properties. The polymerizable crosslinking agent having (meth)acryloyl groups can crosslink not only with other crosslinking agents but also with polyimide precursors when the photosensitive layer is exposed. The polymerizable crosslinking agent having (meth)acryloyl groups may be an acrylate compound or a methacrylate compound. The crosslinking agent may also contain a methacrylate compound from the viewpoint of dielectric properties.

[0070] Examples of polymerizable crosslinking agents having a (meth)acryloyl group include tricyclodecanedimethanol di(meth)acrylate, tris-(2-(meth)acryloyloxyethyl) isocyanurate, dioxaneglycol di(meth)acrylate, alkoxylated glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, alkoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, alkoxylated pentaerythritol tetra(meth)acrylate, and 1,6-hexanedi Examples include all di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated ethoxylated bisphenol A (meth)acrylate, dipentaerythritol poly(meth)acrylate, alkoxylated dipentaerythritol poly(meth)acrylate, ethoxylated isocyanuric acid tri(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate.

[0071] The polymerizable crosslinking agent having a (meth)acryloyl group may contain at least one selected from the group consisting of tricyclodecanedimethanol di(meth)acrylate, tris-(2-(meth)acryloyloxyethyl) isocyanurate, and dioxaneglycol di(meth)acrylate, from the viewpoint of heat resistance, dielectric properties, and microprocessability, and may also contain tris-(2-(meth)acryloyloxyethyl) isocyanurate from the viewpoint of heat resistance and dielectric properties.

[0072] The photosensitive composition according to this embodiment may contain a polymerizable crosslinking agent having allyl groups or vinyl groups as a crosslinking agent, from the viewpoint of dielectric properties and heat resistance. The polymerizable crosslinking agent having allyl groups or vinyl groups can crosslink with each other when the resin film is heated after pattern formation.

[0073] Examples of polymerizable crosslinking agents having an allyl group include 1,3,4,6-tetraallyl glycoluryl, triallyl isocyanurate, diallyl monoglycidyl isocyanurate, diallyl monomethyl isocyanurate, diallyl isocyanurate, triallyl trimellitate, and triallyl orthoformate.

[0074] Examples of polymerizable crosslinking agents having a vinyl group include polyvinylbenzyl compounds and polyvinylbenzyl ether compounds.

[0075] The polymerizable crosslinking agent having an allyl group or a vinyl group may include at least one selected from the group consisting of 1,3,4,6-tetraallyl glycoluryl, triallyl isocyanurate, diallyl isocyanurate, and polyvinyl benzyl ether compounds, from the viewpoint of dielectric properties and microprocessability, and may also include triallyl isocyanurate from the viewpoint of dielectric properties.

[0076] From the viewpoint of further improving the balance between low dielectric properties and microprocessability, the crosslinking agent content is preferably less than 50 parts by mass when the total amount of polyimide precursor and crosslinking agent is 100 parts by mass, and may be 1 to 45 parts by mass, 5 to 40 parts by mass, 8 to 30 parts by mass, or 10 to 20 parts by mass.

[0077] The photosensitive composition according to this embodiment may further contain additives used in photosensitive compositions (for example, photosensitive compositions for forming insulating films) in addition to the above-mentioned components. Examples of such additives include coupling agents, rust inhibitors, radical polymerization inhibitors, and radical polymerization inhibitors.

[0078] The photosensitive composition according to this embodiment may further contain a coupling agent from the viewpoint of improving the adhesion of the cured product of the photosensitive composition. The coupling agent may be a silane coupling agent. The silane coupling agent may have groups such as vinyl groups, epoxy groups, styryl groups, acryloyl groups, methacryloyl groups, amino groups, ureido groups, isocyanate groups, isocyanurate groups, mercapto groups, etc.

[0079] Examples of silane coupling agents containing a vinyl group include KBM-1003 and KBE-1003 (product names of Shin-Etsu Chemical Co., Ltd.; the same applies hereinafter). Examples of silane coupling agents containing an epoxy group include KBM-303, 402, 403, KBE-402, 403, X-12-981S, and X-12-984S. Examples of silane coupling agents containing a styryl group include KBM-1403. Examples of silane coupling agents containing a methacryloyl group include KBM-502, 503, KBE-502, and 503. Examples of silane coupling agents containing an acryloyl group include KBM-5103, X-12-1048, and X-12-1050. Examples of silane coupling agents having an amino group include KBM-602, 603, 903, 573, 575, KBE-903, 9103P, and X-12-972F. Examples of silane coupling agents having a ureido group include KBE-585. Examples of silane coupling agents having an isocyanate group include KBE-9007 and X-12-1159L. Examples of silane coupling agents having an isocyanurate group include KBM-9659. Examples of silane coupling agents having a mercapto group include KBM-802, 803, X-12-1154, and X-12-1156. The silane coupling agent may also be a silane coupling agent having a methacryloyl group. The silane coupling agent can be used alone or in combination of two or more types.

[0080] The silane coupling agent may be present in an amount of 0.01 to 10.0 parts by mass, 0.1 to 8.0 parts by mass, 0.3 to 6.0 parts by mass, 0.5 to 5.0 parts by mass, or 1.0 to 3.0 parts by mass per 100 parts by mass of polyimide precursor (or the total amount of polyimide precursor and crosslinking agent if a crosslinking agent is used).

[0081] The photosensitive composition according to this embodiment may further contain a rust inhibitor from the viewpoint of suppressing corrosion or preventing discoloration of copper wiring. Examples of rust inhibitors include triazole derivatives such as benzotriazole and tetrazole derivatives. The rust inhibitor may be used alone or in combination of two or more types.

[0082] The amount of rust inhibitor may be 0.01 to 10.0 parts by mass, 0.1 to 5.0 parts by mass, 0.3 to 4.0 parts by mass, 0.5 to 3.0 parts by mass, or 1.0 to 3.0 parts by mass per 100 parts by mass of polyimide precursor (or the total amount of polyimide precursor and crosslinking agent if a crosslinking agent is included).

[0083] The photosensitive composition according to this embodiment may further contain a polymerization inhibitor from the viewpoint of storage stability.

[0084] Examples of polymerization inhibitors include 4-tert-butylcatechol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyradical, p-methoxyphenol, diphenyl-p-benzoquinone, benzoquinone, hydroquinone, pyrogallol, phenothiazine, resorcinol, orthodinitrobenzene, paradinitrobenzene, metadinitrobenzene, phenanthaquinone, N-phenyl-2-naphthylamine, cuperone, 2,5-tholquinone, tannic acid, parabenzylaminophenol, tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, and nitrosamines. Polymerization inhibitors may be used individually or in combination of two or more.

[0085] The polymerization inhibitor content may be 0.01 to 10.0 parts by mass, 0.05 to 5.0 parts by mass, 0.10 to 2.0 parts by mass, or 0.10 to 1.0 parts by mass per 100 parts by mass of the polyimide precursor (or the total amount of the polyimide precursor and crosslinking agent if a crosslinking agent is included).

[0086] The photosensitive composition may further contain a sensitizer, from the viewpoint of achieving both the maintenance of residual film ratio over a wide range of exposure levels and good resolution.

[0087] Examples of sensitizers include Michla's ketone, benzoin, 2-methylbenzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, 2-t-butylanthraquinone, 1,2-benzo-9,10-anthraquinone, anthraquinone, methylanthraquinone, 4,4'-bis(diethylamino)benzophenone, acetophenone, benzophenone, thioxanthone, 1,5-acenaphthene, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propanone, diacetylbenzyl, benzyldimethylketal, benzyl Examples include diethyl ketal, diphenyl disulfide, anthracene, phenanthrene quinone, riboflavin tetrabutyrate, acridine orange, erythrosine, phenanthrene quinone, 2-isopropylthioxanthone, 2,6-bis(p-diethylaminobenzylidene)-4-methyl-4-azacyclohexanone, 6-bis(p-dimethylaminobenzylidene)-cyclopentanone, 2,6-bis(p-diethylaminobenzylidene)-4-phenylcyclohexanone, aminostyryl ketone, 3-ketocoumarin compounds, biscoumarin compounds, N-phenylglycine, N-phenyldiethanolamine, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone. Sensitizers may be used individually or in combination of two or more.

[0088] If the photosensitive composition contains a sensitizer, its content is preferably 0.1 to 2.0 parts by mass, and more preferably 0.2 to 1.5 parts by mass, per 100 parts by mass of the polyimide precursor (or the total amount of the polyimide precursor and crosslinking agent if a crosslinking agent is included).

[0089] The means and conditions for preparing the photosensitive composition are not particularly limited. For example, one method involves thoroughly and uniformly stirring and mixing each main component in predetermined amounts using a mixer, and then kneading it using a mixing roll, extruder, kneader, roll, extruder, etc. The kneading method is not particularly limited.

[0090] The relative permittivity (Dk) at 10 GHz of the cured photosensitive composition according to this embodiment may be 4.0 or less, 3.5 or less, or 3.2 or less, from the viewpoint of low dielectric properties. Furthermore, the dielectric loss tangent (Df) at 10 GHz of the cured photosensitive composition may be 0.0300 or less, 0.0200 or less, or 0.0100 or less. The relative permittivity and dielectric loss tangent can be measured using the cured film of the photosensitive composition by the method described in the examples.

[0091] The glass transition temperature (Tg) of the cured product of the photosensitive composition according to this embodiment may be 150°C or higher, 180°C or higher, or 200°C or higher, from the viewpoint of reducing thermal deformation. The glass transition temperature can be measured using the cured film of the photosensitive composition by the method described in the examples.

[0092] The photosensitive composition according to this embodiment can form fine patterns. The photosensitive composition according to this embodiment can form an insulating film that exhibits low dielectric properties and excellent insulating reliability. A semiconductor element having an interlayer insulating layer formed from the cured product of the above-described photosensitive composition, and an electronic device including the semiconductor element can be manufactured. The semiconductor element can have improved high-frequency characteristics by having a redistribution layer containing the cured product of the photosensitive composition according to this embodiment. Furthermore, a surface protective layer of the semiconductor element can also be formed using the photosensitive composition according to this embodiment.

[0093] The semiconductor element may be, for example, a memory, package, etc., having a multilayer wiring structure, a rewiring structure, etc. Examples of electronic devices include mobile phones, smartphones, tablet terminals, personal computers, and hard disk suspensions. By providing a patterned cured film formed with the photosensitive composition of this embodiment, highly reliable semiconductor elements and electronic devices can be provided.

[0094] [Method for manufacturing patterned cured films] One embodiment relating to the method for manufacturing a patterned cured film (resist pattern) of the present disclosure is: The process involves coating a substrate with a photosensitive composition containing the aforementioned polyimide precursor and an organic solvent, and then removing the organic solvent from the photosensitive composition to form a photosensitive layer (coating and drying process). The photosensitive layer is exposed and developed to form a resist pattern (exposure process and development process), The photosensitive layer after the resist pattern is formed is subjected to heat treatment to form a pattern-cured film containing polyimide (heat treatment step), This includes the following. An example of each process is described below.

[0095] (Coating and drying process) First, a photosensitive composition is applied to a substrate and dried to form a resin film. In this step, the photosensitive composition is applied to a substrate such as a glass substrate, semiconductor, metal oxide insulator (TiO2, SiO2, etc.), or silicon nitride using a spinner or the like, to form a coating film. The substrate with this coating film is then dried using a hot plate, oven, or the like. The drying temperature may be 80-140°C, 90-135°C, or 100-130°C, and the drying time may be 1-7 minutes, 1-6 minutes, or 2-5 minutes. This forms a resin film on the substrate.

[0096] (Exposure process) Next, in the exposure process, the resin film formed on the substrate is irradiated with active light such as ultraviolet light, visible light, or radiation through a mask. In the above-mentioned photosensitive composition, the polyimide precursor has high transparency to i-rays, so i-ray irradiation can be suitably used. After exposure, post-exposure heating (PEB) can be performed as needed. The temperature for post-exposure heating is preferably 70°C to 140°C, and the duration for post-exposure heating is preferably 1 to 5 minutes.

[0097] (Development process) In the developing process, the exposed or unexposed areas of the resin film after the exposure process are removed with a developer, thereby patterning the resin film and obtaining a patterned resin film. If the photosensitive composition is positive type, the exposed areas are removed with the developer. If the photosensitive composition is negative type, the unexposed areas are removed with the developer.

[0098] When developing with an alkaline aqueous solution, suitable developers include, for example, alkaline aqueous solutions of sodium hydroxide, potassium hydroxide, sodium silicate, ammonia, ethylamine, diethylamine, triethylamine, triethanolamine, and tetramethylammonium hydroxide (TMAH). The base concentration of these aqueous solutions is preferably 0.1 to 10% by mass. Alcohols or surfactants can also be added to the above developer. These may be added in amounts ranging from 0.01 to 10 parts by mass or 0.1 to 5 parts by mass, respectively, per 100 parts by mass of the developer.

[0099] When developing with organic solvents, good solvents such as cyclopentanone, N,N-dimethylformamide, dimethyl sulfoxide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, and acetate esters are used as the developing solution, or mixed solvents of these good solvents with poor solvents such as lower alcohols, water, and aromatic hydrocarbons are used.

[0100] (Heat treatment process) In the heat treatment process, a patterned resin film can be heat-treated to form a patterned cured film (resist pattern). The heating temperature in the heat treatment process may be 170-260°C, 180-250°C, or 190-240°C, in order to sufficiently prevent thermal damage to electronic devices.

[0101] The heat treatment can be carried out using an oven such as a quartz tube furnace, hot plate, rapid thermal annealing, vertical diffusion furnace, infrared curing furnace, electron beam curing furnace, or microwave curing furnace. Furthermore, the treatment can be performed in either air or an inert atmosphere such as nitrogen, but using nitrogen is preferable as it prevents oxidation of the pattern. Since the above-mentioned heating temperature range is lower than conventional heating temperatures, damage to the substrate and electronic devices can be minimized. Therefore, by using the method for manufacturing pattern-cured films according to this embodiment, electronic devices can be manufactured with high yield.

[0102] The heating time in the heat treatment process should be sufficient for the photosensitive composition to harden, but is generally preferred to be 5 hours or less, taking into account work efficiency. The heating time may be 1.0 to 2.5 hours, 1.5 to 2.5 hours, or 1.8 to 2.2 hours.

[0103] In addition to the oven described above, the heat treatment can also be performed using a microwave curing device or a variable-frequency microwave curing device. By using these devices, it is possible to effectively heat only the resin film while maintaining the temperature of the substrate and electronic device at the desired temperature (e.g., 200°C or below).

[0104] In a variable frequency microwave curing apparatus, microwaves are irradiated in a pulsed manner while varying their frequency, which prevents standing waves and allows for uniform heating of the substrate surface. Furthermore, when the substrate contains metal wiring, such as in the electronic components described later, irradiating with microwaves in a pulsed manner while varying the frequency prevents the generation of discharges from the metal, protecting the electronic components from damage. Moreover, heating using variable frequency microwaves results in less deterioration of the physical properties of the cured film even when the curing temperature is lowered compared to when using an oven (see J. Photopolym. Sci. Technol., 18, 327-332 (2005)).

[0105] The frequency of a tunable microwave is in the range of 0.5 to 20 GHz, but in practice, it may be in the range of 1 to 10 GHz or 2 to 9 GHz. While it is desirable to continuously change the frequency of the irradiated microwave, in practice, the frequency is changed in a stepwise manner. In this case, the irradiation time of a single-frequency microwave should be as short as possible to minimize the occurrence of standing waves and discharges from metals; therefore, the microwave irradiation time is preferably 1 millisecond or less, and more preferably 100 microseconds or less.

[0106] The output power of the microwaves used for irradiation varies depending on the size of the device or the amount of material being heated, but is generally in the range of 10 to 2000 W. In practical terms, it may be 100 to 1000 W, 100 to 700 W, or 100 to 500 W. An output of 10 W or more makes it easier to heat the material being heated in a short time, while an output of 2000 W or less makes it less likely for a rapid temperature rise to occur.

[0107] It is preferable to irradiate with microwaves in a pulsed on / off manner. Pulsed microwave irradiation is preferable because it allows the set heating temperature to be maintained and damage to the cured film and substrate to be avoided. The duration of each pulsed microwave irradiation varies depending on the conditions, but it is generally preferable to 10 seconds or less.

[0108] According to the method for manufacturing a patterned cured film as described above, a patterned cured film can be obtained with sufficiently high sensitivity and resolution, and excellent properties such as heat resistance and low dielectric properties. [Examples]

[0109] The present disclosure will be described in more detail below with reference to examples. However, the present invention is not limited to these examples.

[0110] [Preparation of polyimide precursors] The materials used to produce the polyimide precursor in the example are shown below. <(A) Component: Tetracarboxylic acid dianhydride> A-1: 4,4'-Oxydiphthalic anhydride (ODPA, molecular weight: 310.0) A-2: Bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid)1,4-phenylene (TAHQ, molecular weight: 458.3) A-3: 4,4'-(4,4'-isopropylidenediphenoxy)diphthalic anhydride (BPADA, molecular weight: 520.5) <(B) Component: Amine> B-1: 3,3'-Diaminobenzidine (DAB, Molecular weight: 214.0) B-2: 4,4'-diaminodiphenyl ether (4,4'-ODA, molecular weight: 200.2) B-3: 2,2'-Dimethylbenzidine (m-Tolidine, molecular weight: 212.3) B-4: Dimer amine (DDA, Priamin 1075®, manufactured by Croda Japan Co., Ltd., molecular weight: 416.0) <(C) Component: Compound having reactive and photosensitive groups for amines> C-1:2-Isocyanatoethyl methacrylate (Kalenz MOI, manufactured by Resonaq Corporation, molecular weight: 155.2) C-2: 2-(2-methacryloyloxyethyloxy)ethyl isocyanate (Kalenz MOI-EG (manufactured by Resonac Co., Ltd.), molecular weight: 199.2) C-3: Methacrylic anhydride (Molecular weight: 154.2) C-4:2-Isocyanatoethyl acrylate (Kalenz AOI (manufactured by Resonac Co., Ltd.), molecular weight: 141.1) C-5: Allyl succinic anhydride (molecular weight: 140.1) <(D) Component: Hydroxy compound> D-1: Isopropanol (Molecular weight: 60.1, Boiling point: 82°C) D-2: Methoxybenzyl alcohol (molecular weight: 138.2, boiling point: 259°C) D-3: 3-Methoxy-1-butanol (Molecular weight: 104.2, Boiling point: 158°C) D-4: Hydroxyethyl methacrylate (HEMA, molecular weight: 130.1, boiling point: 85°C / 5mmHg (230)) D-5: Long-chain acrylate (Molecular weight: 144.2, Boiling point: 95°C / 0.1 mmHg (325)) <(E) Component: Organic solvent> E-1: N-methyl-2-pyrrolidone (NMP, boiling point: 204°C) E-2:3-Methoxy-N,N-dimethylpropanamide (MPA, boiling point: 215°C)

[0111] <Example 1> In a 300 mL separable flask, 6.20 g (20.0 mmol) of ODPA, 4.89 g (61.8 mmol) of pyridine, 2.43 g (40.4 mmol) of 2-propanol (isopropanol), and 13.0 g of NMP were added and stirred for 2 hours while being heated to 60°C. The mixture was then cooled to 5°C in an ice bath. To the ice-cooled mixture, 8.25 g (40.0 mmol) of DCC dissolved and diluted in 9 g of NMP was added dropwise over approximately 20 minutes, and the mixture was stirred for 1 hour. Next, 4.29 g (20.0 mmol) of DAB dissolved in 18.0 g of NMP was added dropwise to the ice-cold mixture over a period of about 10 minutes. After the addition, the mixture was stirred for 1 hour while maintaining its temperature below 5°C in an ice bath. Furthermore, 7.05 g (50 mmol) of Karenz MOI (manufactured by Resonac Co., Ltd.) was added dropwise to the mixture under ice cooling, and then the ice bath was removed and the mixture was stirred at room temperature for 1 hour. Subsequently, a few drops of ethanol were added to the mixture, and the precipitate formed during the polycondensation process was filtered off under pressure to recover the filtrate (polymer solution). The recovered polymer solution was added dropwise to 2 L of pure water or ethanol, and the precipitated polymer was collected by filtration and redissolved in 80 g of NMP. After repeating this process three times, the polyimide precursor was obtained by vacuum drying at 65°C for 24 hours.

[0112] <Examples 2-14> A polyimide precursor was prepared in the same manner as in Example 1, except that the materials shown in Tables 1 and 2 were used for components (A) to (E). In Tables 1 and 2, the values ​​in the columns for components (A) to (D) indicate the molar ratio.

[0113] <Example 15> 4.29 g (20.0 mmol) of DAB and 48.4 g of NMP were placed in a 300 mL separable flask and cooled to below 5°C in an ice bath. To the ice-cooled mixture, 6.2 g (20.0 mmol) of ODPA dissolved in 24.2 g of MPA was added dropwise over approximately 30 minutes. After addition, the mixture was stirred for 2 hours while maintaining its temperature below 5°C in an ice bath. Then, the ice bath was removed and the mixture was stirred at room temperature for 2 hours. Next, the mixture was cooled to 5°C in an ice bath, and 7.05 g (50 mmol) of currant MOI was added. After adding the currant, the ice bath was removed again, and the mixture was stirred at room temperature for 1 hour. Subsequently, a few drops of ethanol were added, and the precipitate formed during the polycondensation process was filtered off under pressure to recover the filtrate (polymer solution). The recovered polymer solution was added dropwise to 2 L of ethanol, the precipitated polymer was collected by filtration, and redissolved in 80 g of MPA. After repeating this process three times, the polyimide precursor was obtained by vacuum drying at 65°C for 24 hours.

[0114] <Examples 16-21> A polyimide precursor was prepared in the same manner as in Example 15, except that the materials shown in Table 3 were used for components (A) to (E). In Table 3, the values ​​in the columns for components (A) to (D) indicate the molar ratio.

[0115] Tables 1-3 show the proportion (mol%) of triamine and tetraamine in the total amount of component (B) in Examples 1-21, as well as the number-average molecular weight (Mn) and weight-average molecular weight of the obtained polyimide precursors. Mn and Mw were measured by gel permeation chromatography (GPC, columns: Shodex KD-806L x 2, DMF / THF mixture, flow rate: 1.0 ml / min), and the values ​​were converted using standard polystyrene as the standard sample. NMP was used as the eluent in this measurement.

[0116] [Table 1]

[0117] [Table 2]

[0118] [Table 3]

[0119] [Preparation of photosensitive composition] Photosensitive compositions having the compositions shown in Tables 4 to 6 were prepared using the polyimide precursors of Examples 1 to 21. The crosslinking agent, photopolymerization initiator, coupling agent, polymerization inhibitor, rust inhibitor, and organic solvent used in each example are as follows. Tables 4 to 6 also show the amount of non-volatile content (NV) contained in each photosensitive composition. <(F) Ingredient: Crosslinking agent> F-1: Tris(2-acryloyloxyethyl) isocyanurate (A-9300S, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) F-2: Dioxane glycol diacrylate (A-DOG, manufactured by Shin-Nakamura Chemical Co., Ltd.) F-3: 1,6-Hexanediol diacrylate (A-HD-N, manufactured by Shin-Nakamura Chemical Co., Ltd.) <(G) Component: Photopolymerization initiator> G-1: 1,2-Octanedione-1-[4-(phenylthio)phenyl]-2-(o-benzoyloxime) (Irgacure OXE-01, manufactured by BASF Japan Ltd.) G-2: 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(O-acetyloxime) (Irgacure OXE-02, manufactured by BASF Japan Ltd.) <(H) Component: Coupling agent> H-1:3-Methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) <(I) Ingredient: Polymerization inhibitor> I-1:4-Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyradical (TEMPOL, manufactured by Tokyo Chemical Industry Co., Ltd.) <(J) Ingredients: Rust inhibitor> J-1: Benzotriazole-based rust inhibitor (BT-120GT, manufactured by Johoku Chemical Industry Co., Ltd.) <(K) component: organic solvent> K-1: N-methyl-2-pyrrolidone E-2:3-Methoxy-N,N-dimethylpropanamide

[0120] [Measurement of glass transition temperature (Tg)] The Tg of films prepared using the photosensitive compositions of Examples 1 to 21 was measured according to the following procedure. A photosensitive composition was dropped onto a wafer and a film was formed by spin coating. A photosensitive layer (thickness: 10 μm) was formed by heating at 110°C for 2 minutes to remove the organic solvent from the coating. Subsequently, broadband (BB) exposure was performed on the photosensitive layer using an exposure apparatus (Mikasa Corporation, product name: ML-320FSAT), and then the photosensitive layer was cured by heating at 230°C for 2 hours under a nitrogen atmosphere to obtain a cured product. After peeling the cured product from the wafer, the linear thermal expansion coefficient (CTE) of the cured product was measured by thermomechanical analysis. The glass transition temperature was obtained as the intersection of the tangent in the temperature range of 50-100°C and the tangent in the temperature range above the glass transition temperature (e.g., 250-320°C). The obtained results are shown in Tables 4-6.

[0121] [Dielectric properties] Test specimens (60 mm × 60 mm) were prepared using a cured material with the same glass transition temperature as described above. The relative permittivity (Dk) and dielectric loss tangent (Df) of the test specimens at 10 GHz were measured at an ambient temperature of 25°C using a vector network analyzer MS46122B (manufactured by Anritsu Corporation) and a split cylinder resonator (manufactured by AET Corporation, TE mode). The obtained results are shown in Tables 4 to 6.

[0122] [Evaluation of developability] The photosensitive compositions of Examples 1 to 21 were evaluated for solvent developability (developer: cyclopentanone) and alkali developability (developer: 1% Na2CO3 aqueous solution) using the following procedure. Each resin varnish was dropped onto a wafer and deposited by spin coating. The solvent was removed from the coating by heating at 110°C for 2 minutes to form a resin film. Each developer was then dropped onto the resulting resin film, and its developability was evaluated based on the following evaluation rank. (Rating Rank) A: Dissolved (no residue) B: Dissolved (residue present) C: Insoluble The results obtained are shown in Tables 4-6.

[0123] [Table 4]

[0124] [Table 5]

[0125] [Table 6]

Claims

1. A polyimide precursor containing a structural unit represented by the following formula (1). 【Chemistry 1】 [In the formula, X １ This indicates a tetravalent organic group, Y １ represents an (n+2)-valent organic group, Z represents a monovalent organic group containing a photosensitive group, and L １ and L ２ Each independently represents either an oxy group or an amino group, L ３ indicates an (m+1) valent amino group, R １ and R ２ Each of these independently represents a hydrogen atom or a monovalent organic group, where m represents 1 or 2, and n represents 1 or 2.

2. The aforementioned Y １ The polyimide precursor according to claim 1, wherein the structure comprises a structure represented by the following formula (2a) or (2b). 【Chemistry 2】 [In the formula, L ４ represents a divalent linking group, and p represents 0 or 1.]

3. The polyimide precursor according to claim 1, further comprising a structural unit represented by the following formula (3). 【Transformation 3】 [In the formula, X １ This indicates a tetravalent organic group, Y ２ This represents a divalent organic group that does not have a photosensitive group, L １ and L ２ Each independently represents either an oxy group or an amino group, R １ and R ２ Each of these independently represents a hydrogen atom or a monovalent organic group.

4. The aforementioned Y ２ The polyimide precursor according to claim 3, wherein it comprises a residue obtained by removing two amino groups from a diamine having an aromatic ring and / or an alicyclic ring.

5. The aforementioned X １ The polyimide precursor according to claim 1, wherein the structure is represented by the following formula (4). 【Chemistry 4】 [In the formula, L ５ [where 'q' indicates a divalent linking group, and 'q' indicates 0 or 1.]

6. The polyimide precursor according to claim 1, wherein Z has at least one photosensitive group selected from the group consisting of an acryloyl group, a methacryloyl group, a vinyl group, and a styryl group.

7. In the presence of N,N'-dicyclohexylcarbodiimide, a compound represented by the following formula (5) is reacted with an amine containing at least one selected from the group consisting of triamines and tetraamines to obtain a compound containing a structural unit represented by the following formula (6). The method involves reacting a compound represented by the following formula (6) with a compound having a reactive group for an amino group and a photosensitive group to obtain a polyimide precursor containing a structural unit represented by the following formula (1), A method for producing a polyimide precursor containing [the specified ingredient]. 【Transformation 5】 【Transformation 6】 【Transformation 7】 [In the formula, X １ This indicates a tetravalent organic group, Y １ represents an (n+2)-valent organic group, Z represents a monovalent organic group containing a photosensitive group, and L １ and L ２ Each independently represents either an oxy group or an amino group, L ３ indicates an (m+1) valent amino group, R １ and R ２ Each of these independently represents a hydrogen atom or a monovalent organic group, where m represents 1 or 2, and n represents 1 or 2.

8. A compound containing a structural unit represented by the following formula (7) is obtained by reacting a tetracarboxylic dianhydride with an amine containing at least one selected from triamines and tetraamines. A compound containing a structural unit represented by the following formula (7) is reacted with a compound having a reactive group for an amino group and a photosensitive group to obtain a polyimide precursor containing a structural unit represented by the following formula (8), A method for producing a polyimide precursor containing [the specified ingredient]. 【Transformation 8】 【Chemistry 9】 [In the formula, X １ This indicates a tetravalent organic group, Y １ This indicates an (n+2) valent organic group, L ３ [where 'm' indicates an (m+1) valent amino group, 'Z' indicates a monovalent organic group containing a photosensitive group, 'm' indicates 1 or 2, and 'n' indicates 1 or 2.]

9. A method for producing a polyimide precursor according to claim 8, further comprising reacting a polyimide precursor containing a structural unit represented by formula (8) with a compound having a reactive group for a carboxylic acid group to obtain a polyimide precursor containing a structural unit represented by the following formula (9). 【Chemistry 10】 [In the formula, X １ This indicates a tetravalent organic group, Y １ represents an (n+2)-valent organic group, Z represents a monovalent organic group containing a photosensitive group, and L １ and L ２ Each independently represents either an oxy group or an amino group, L ３ indicates an (m+1) valent amino group, R ３ and R ４ Each of these independently represents a monovalent organic group, where m represents 1 or 2, and n represents 1 or 2.

10. A photosensitive composition comprising the polyimide precursor described in claim 1 and an organic solvent.

11. The photosensitive composition according to claim 10, further comprising a photopolymerization initiator.

12. The photosensitive composition according to claim 10, further comprising a crosslinking agent.

13. A photosensitive composition containing the polyimide precursor described in claim 1 and an organic solvent is applied to a substrate, and the organic solvent is removed from the photosensitive composition to form a photosensitive layer. The photosensitive layer is exposed and developed to form a resist pattern, The photosensitive layer after the resist pattern is formed is subjected to heat treatment to form a pattern-cured film containing polyimide, A method for manufacturing a patterned cured film, including the method described above.

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