Photosensitive resin composition, photosensitive resin sheet using said photosensitive resin composition, cured product, cured product film production method, and semiconductor device and display device including said cured product

Abstract

The present invention addresses the problem of providing a photosensitive resin composition that has high sensitivity and is capable of pattern formation in which the shrinkage of patterns during a curing reaction performed after exposure and development is small. The present invention provides a photosensitive resin composition comprising: a polybenzoxazole precursor having a repeating unit represented by formula (1); and a photoacid generator. (R1 and R2 each independently represent a hydrogen atom, a C1-C6 alkyl group, or a C1-C120 monovalent acid-labile group. X represents a divalent linking group. V represents a C1-C3 linear or branched divalent aliphatic hydrocarbon group or a divalent aliphatic hydrocarbon group represented by formula (9).) (n represents an integer of 0-11 and m represents an integer of 1-12. Here, n+m is 1-12. R20 and R21 are each a C2-C4 hydrocarbon group when n=0, and a C1-C4 hydrocarbon group when n≠0. * represents a bonding point to an amide group.)

Description

Photosensitive resin composition, photosensitive resin sheet using said photosensitive resin composition, method for producing a cured product and a cured product film, and semiconductor device and display device including said cured product

[0001] The present invention relates to a photosensitive resin composition suitable for use in semiconductor devices, and also to a photosensitive resin sheet, semiconductor device, and display device using the photosensitive resin composition or a cured product thereof.

[0002] Polyimide resins, polybenzoxazole resins, and the like, which have excellent heat resistance, electrical insulation properties, and mechanical properties, are widely used in surface protection films and interlayer insulating films used in semiconductor devices, insulating layers in organic electroluminescent devices, and planarizing films for thin film transistor (TFT) substrates. In recent years, photosensitive resin compositions in which photosensitivity has been imparted to these resins themselves or their precursors have been used (hereinafter, these photosensitive resin compositions will be referred to as "photosensitive resin compositions such as polyimide resins"). The use of photosensitive resin compositions such as polyimide resins can simplify the pattern processing step and shorten the complicated manufacturing process.

[0003] For photosensitive resin compositions such as polyimide resins, there have been proposed positive-type compositions in which the exposed areas are readily soluble in a developer and can be patterned, and negative-type compositions in which the composition itself is readily soluble and the exposed areas are insoluble in a developer. Generally, positive-type photosensitive resin compositions such as polyimide resins have superior resolution compared to negative-type compositions, and therefore are used in applications requiring fine processing.

[0004] Known positive-type photosensitive resin compositions such as polyimide resins include those in which a quinone diazide compound is added to a polyimide, polybenzoxazole, polyimide precursor, or polybenzoxazole precursor (see, for example, Patent Document 1), those in which a photoacid generator is added to a polyamide containing a protecting group that can be cleaved in the presence of an acid (see, for example, Patent Document 2), and those in which an aliphatic hydrocarbon group with low light absorption is introduced into a polyamide structure (see, for example, Patent Document 3).

[0005] JP 2011-180473 A JP 2011-221173 A International Publication No. 2016 / 035819

[0006] In recent years, due to reasons such as increasing substrate size and improving productivity, there has been a need for photosensitive resin compositions to have higher sensitivity and resolution.

[0007] The technology described in Patent Document 1 combines an alkali-soluble resin with a quinone diazide compound. The quinone diazide compound interacts with the alkali-soluble resin to reduce the solubility of the composition in an alkaline developer. On the other hand, the quinone diazide compound undergoes a photochemical reaction upon exposure to light, becoming an indene carboxylic acid compound, which acts as a dissolution promoter in the alkaline developer. This results in a difference in dissolution rate between the unexposed and exposed areas, enabling pattern processing. In this technology, sensitivity depends on the amount of quinone diazide compound added, but increasing the amount of quinone diazide compound limits the improvement in sensitivity because the photochemical reaction rate decreases due to the light absorption of the quinone diazide itself.

[0008] The technology of Patent Document 2 involves substituting the hydrogen atoms of hydroxyl groups in an alkali-soluble polyamide with protecting groups that can be removed in the presence of acid to produce an alkali-insoluble resin, which is then combined with a photoacid generator. This technology uses acid generated from the photoacid generator in exposed areas to remove the protecting groups from the polyamide, converting the polyamide from an alkali-insoluble to an alkali-soluble resin. This results in a difference in dissolution rate between exposed and unexposed areas, enabling positive-tone pattern processing. However, this technology suffers from the problem of insufficient sensitivity improvement due to the low acid generation efficiency of the photoacid generator, which is inhibited by the light absorption of the polyamide.

[0009] The technology of Patent Document 3 uses polyamide into which an aliphatic skeleton with high light transmittance has been introduced, and is expected to improve the acid generation efficiency of a photoacid generator. However, since a straight-chain aliphatic hydrocarbon having four or more carbon atoms is used, there is a problem that the pattern shrinks during the curing reaction.

[0010] An object of the present invention is to provide a photosensitive resin composition which has high sensitivity and is capable of forming a pattern with little shrinkage of the pattern during the curing reaction carried out after exposure and development.

[0011] The main aspects of the photosensitive resin composition of the present invention are as follows: [1] A photosensitive resin composition containing a polybenzoxazole precursor having a repeating unit represented by formula (1) (hereinafter, sometimes referred to as "component (a)") and a photoacid generator (hereinafter, sometimes referred to as "photoacid generator (b)").

[0012]

[0013] (R １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. X represents a divalent linking group. V represents a linear or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms or a divalent aliphatic hydrocarbon group represented by formula (9).

[0014]

[0015] (n represents an integer of 0 to 11, and m represents an integer of 1 to 12, provided that n+m is 1 to 12. R ２０ and R ２１ is a hydrocarbon group having 2 to 4 carbon atoms when n=0, and is a hydrocarbon group having 1 to 4 carbon atoms when n≠0. * represents a bonding point with an amide group. [2] The photosensitive resin composition according to [1] above, wherein in the repeating unit represented by formula (1), V is a linear or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms. [3] In the repeating unit represented by formula (1), R １ and R ２ The photosensitive resin composition according to any one of [1] to [2] above, wherein either or both of the above, when both are present, are independently an alkyl group having 1 to 6 carbon atoms or a monovalent acid-decomposable group having 1 to 120 carbon atoms. [4] The photosensitive resin composition according to any one of [1] to [3] above, wherein component (a) contains a repeating unit represented by formula (1) above and a repeating unit represented by formula (2) below:

[0016]

[0017] (R ３ and R ４each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. Y represents a divalent linking group. U represents a divalent aliphatic hydrocarbon group having 3 to 30 carbon atoms and containing an alicyclic skeleton, or a straight-chain or branched divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms (excluding groups corresponding to the divalent aliphatic hydrocarbon group represented by formula (9) above). The present invention also provides various improved aspects of the photosensitive resin composition of the present invention, as well as a cured product of the photosensitive resin composition of the present invention, and uses of the photosensitive resin composition and the cured product of the present invention.

[0018] The photosensitive resin composition of the present invention has high sensitivity and is capable of forming a pattern with little shrinkage by suppressing reflow during curing.

[0019] FIG. 2 is a schematic cross-sectional view illustrating a taper angle.

[0020] The present invention provides a photosensitive resin composition comprising a polybenzoxazole precursor (component (a)) having a repeating unit represented by formula (1) and a photoacid generator (photoacid generator (b)).

[0021]

[0022] In formula (1), R １ , and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. X represents a divalent linking group. V represents a linear or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms or a divalent aliphatic hydrocarbon group represented by formula (9). Here, -OR １ and -OR ２ is attached to the ortho position of an amide bond attached to the same aromatic ring or to a carbon atom adjacent to the carbon atom to which the amide bond is attached, and allows conversion to an oxazole ring.

[0023] <Polybenzoxazole precursor having a repeating unit represented by formula (1) (component (a))> The photosensitive resin composition of the present invention contains a polybenzoxazole precursor having a repeating unit represented by formula (1) (component (a)).

[0024]

[0025] In formula (1), R １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms.

[0026] The acid-decomposable group referred to here is a group that can be decomposed by the acid generated from the photoacid generator upon exposure to light, and can be decomposed by the -OR group in formula (1). １ and -OR ２ This refers to a functional group that can act on the photosensitive resin and convert it to -OH (phenolic hydroxyl group). The phenolic hydroxyl group increases the dissolution rate in an alkaline developer, so the difference in dissolution rate between the unexposed and exposed areas during development increases, allowing the exposed areas to dissolve, forming a relief pattern.

[0027] When an acid-decomposable group is used, -OR １ , -OR ２ The structure of can be converted into a phenolic hydroxyl group by the action of an acid. １ , -OR ２ The structure of the formula (I) is sometimes referred to as a "hydroxyl group protected by an acid-decomposable group." １ , -OR ２ The conversion of -OH to -OR by reaction with a protecting agent is called "deprotection." １ , -OR ２ The converted ratio is called the "protection rate."

[0028] In particular, when V is a straight-chain or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms or a divalent aliphatic hydrocarbon group represented by formula (9), the dissolution rate of the unexposed portion of the film when made into a photosensitive resin composition in an alkaline developer tends to be higher compared to when V has other structures. From the viewpoint of increasing the difference in dissolution rate between the exposed portion and the unexposed portion and thereby increasing sensitivity by decreasing the dissolution rate of the unexposed portion and thereby reducing the amount of film loss during development, and from the viewpoint of improving the solubility of the photosensitive resin composition in thinners (low-boiling point solvents) used for edge rinsing and back rinsing of a substrate to which the photosensitive resin composition has been applied, R １ and R２ Preferably, either or both of the above, when both are present, are each independently an alkyl group having 1 to 6 carbon atoms or a monovalent acid-decomposable group having 1 to 120 carbon atoms.

[0029] In addition, the dissolution rate of the exposed area is increased by the action of acid, which increases the difference in dissolution rate between the exposed area and the unexposed area, thereby increasing the sensitivity. １ and R ２ It is more preferable that either or both of the above, when both are present, are each independently a monovalent acid-decomposable group having 1 to 120 carbon atoms.

[0030] Specific examples of the monovalent acid-decomposable group having 1 to 120 carbon atoms include, but are not limited to, a t-butoxycarbonyl group, a t-butyl group, a tetrahydropyranyl group, and an (α-oxyalkyl)alkylene group.

[0031] From the viewpoint of improving the solubility of the photosensitive resin composition in a thinner (a low-boiling point solvent) used for edge-back rinsing of a substrate to which the photosensitive resin composition has been applied, and from the viewpoint of increasing sensitivity, the acid-decomposable group having 1 to 120 carbon atoms is preferably a t-butoxycarbonyl group or an (α-oxyalkyl)alkylene group, and more preferably an (α-oxyalkyl)alkylene group.

[0032] The (α-oxyalkyl)alkylene group is —O—CR , including the oxygen to which the group is bonded. ２ It is a group that forms an —O— bond (R is hydrogen or an alkyl group). However, in the (α-oxyalkyl)alkylene group, the alkyl group and alkylene group in the (α-oxyalkyl)alkylene group may have hydrogen atoms in the alkyl group or alkylene group (excluding hydrogen atoms when the atom bonded to the α-position is hydrogen) substituted with an oxyalkyl group, or may form a ring structure between two or more alkyl groups or between an alkyl group and an alkylene group. Specific examples of the structure include those shown in the following formula:

[0033]

[0034] In the above structure, R ７ ~R １２ , R １４ represents a monovalent organic group, and R１３ and R １５ indicates a divalent organic group. * indicates a bonding point with oxygen. R １ and R ２ The number of carbon atoms contained therein is preferably 3 to 20.

[0035] Examples of the monovalent organic group include an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 10 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms, and an alkoxycyclic alkyl group having 6 to 16 carbon atoms.

[0036] Examples of the divalent organic group include a propane-1,3-diyl group, a butane-1,3-diyl group, a pentane-1,3-diyl group, and a group in which a hydrogen atom of a group selected from the group consisting of a propane-1,3-diyl group, a butane-1,3-diyl group, and a pentane-1,3-diyl group has been substituted with a group selected from the group consisting of an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxyalkyl group having 2 to 8 carbon atoms.

[0037] From the viewpoint of increasing sensitivity, a more preferred specific example of the (α-oxyalkyl)alkylene group is a group represented by formula (4).

[0038]

[0039] In formula (4), R １６ represents an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 8 carbon atoms. １７ and R １８ represents an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 10 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms, or an alkoxycyclic alkyl group having 6 to 16 carbon atoms. １９ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 10 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms, or an alkoxycyclic alkyl group having 6 to 16 carbon atoms. １７ , R １８ and R １９ In two or all of these groups, the hydrogen atoms may be replaced with direct bonds to form a ring structure. * indicates the point of attachment to oxygen.

[0040] Specific examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, and hexyl groups.

[0041] Specific examples of alkoxyalkyl groups having 2 to 8 carbon atoms include, for example, a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, an ethoxymethyl group, an ethoxyethyl group, an ethoxypropyl group, an ethoxybutyl group, a propoxymethyl group, a propoxyethyl group, a propoxypropyl group, and a propoxybutyl group.

[0042] Specific examples of the cyclic alkyl group having 5 to 10 carbon atoms include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentylmethyl group, a cyclohexylmethyl group, a cycloheptylmethyl group, a cyclopentylethyl group, a cyclohexylethyl group, a cycloheptylethyl group, a cyclopentylpropyl group, a cyclohexylpropyl group, and a cycloheptylpropyl group.

[0043] Specific examples of the alkoxy cyclic alkyl group having 6 to 16 carbon atoms include a methoxypentyl group, an ethoxypentyl group, a propoxypentyl group, a dimethoxypentyl group, a diethoxypentyl group, a dipropoxypentyl group, a trimethoxypentyl group, a triethoxypentyl group, a tripropoxypentyl group, a methoxyhexyl group, an ethoxyhexyl group, a propoxyhexyl group, a dimethoxyhexyl group, a diethoxyhexyl group, a dipropoxyhexyl group, a trimethoxyhexyl group, a triethoxyhexyl group, a tripropoxyhexyl group, a methoxyheptyl group, an ethoxyheptyl group, a propoxyheptyl group, a dimethoxyheptyl group, a diethoxyheptyl group, a dipropoxyheptyl group, a trimethoxyheptyl group, a triethoxyheptyl group, and a tripropoxyheptyl group.

[0044] Specific examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, and a hexoxy group.

[0045] Formula (4) is -OR１ , -OR ２ R １ , R ２ is an (α-oxyalkyl) alkylene group, the carbon atom at the γ position, i.e., R １７ Or R １９ is a secondary carbon or a tertiary carbon. １ , R ２ is a group represented by formula (4), １ , -OR ２ The activation energy for converting R to a phenolic hydroxyl group, i.e., deprotection, can be reduced. Therefore, even if only a small amount of acid is generated in the photosensitive composition upon exposure, deprotection can be performed, and a highly sensitive photosensitive resin composition can be obtained. Specifically, R １ , R ２ A group represented by any one of formulas (5) to (7) is preferably used, and a group represented by formula (7) is particularly preferably used.

[0046]

[0047] In formulas (5) to (7), * represents the point of attachment to oxygen.

[0048] The structure of a hydroxyl group protected by an acid-decomposable group can be obtained by reacting a resin having a hydroxyl group, including a phenolic hydroxyl group, with a protecting agent. For example, the resin having a hydroxyl group and the protecting agent are reacted in the presence of an acid or a base at a reaction temperature of −20 to 50° C. without a solvent or in a solvent such as toluene, hexane, propylene glycol monomethyl ether acetate, or cyclopentanone, to obtain —OR １ , -OR ２ In this way, a component (a) can be obtained in which the moiety is a hydroxyl group protected with an acid-decomposable group.

[0049] The protecting agent used in the present invention is a compound capable of protecting a hydroxyl group, and the protecting group introduced thereby can be deprotected by the action of an acid or a base. Any known protecting agent capable of protecting a hydroxyl group can be used as the protecting agent.

[0050] Examples of the protecting agent include R １ , R２ is a 1-ethoxyethyl group, R １ , R ２ is an isobutyl vinyl ether when R is an 1-isobutylethyl group. １ , R ２ is a 2-tetrahydropyranyl group, R １ , R ２ When is to be a t-butoxycarbonyl group, di-tert-butyl dicarbonate can be used.

[0051] An acid or base catalyst can be used in the reaction of a resin having a hydroxyl group, including a phenolic hydroxyl group, with a protecting agent to obtain a resin having a hydroxyl group structure protected by an acid-decomposable group.

[0052] Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and perchloric acid, and organic acids such as methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and trifluoroacetic acid. Organic acid salts such as pyridinium p-toluenesulfonate can also be preferably used.

[0053] Examples of the base catalyst include amine compounds such as pyridine, N,N-diethyl-4-aminopyridine, triethylamine, and diisopropylamine.

[0054] In the formula (1), X is a divalent linking group. Here, the divalent linking group refers to a direct bond, a divalent hydrocarbon group, or a divalent group chemically equivalent thereto, which connects two adjacent phenyl groups. Examples include a direct bond, a divalent aromatic or aliphatic hydrocarbon group, and a divalent heterocycle, as well as a structure in which a divalent aromatic hydrocarbon group, a divalent aliphatic hydrocarbon group, and a divalent heterocycle are linked by a direct bond, a sulfonyl group, an ether bond, a sulfide bond, a carbonyl group, a carboxylic acid ester bond, an amide bond, a urea bond, a urethane bond, a carbonate ester bond, a carbonyloxy group, or a carbonylamide group. In addition, the divalent aromatic hydrocarbon group, the divalent aliphatic hydrocarbon group, and the divalent heterocycle may be bonded to a monovalent functional group containing a heteroatom, such as an oxyalkyl group, an oxyaryl group, a thioalkyl group, a thioaryl group, an aminocarbonylalkyl group, a cyano group, or a halogen group, within the scope of not impairing chemical equivalence. Here, the term "chemically equivalent" means that the X is as stable as a direct bond or a divalent hydrocarbon group during the process of curing the photosensitive resin composition of the present invention, i.e., that its structure does not change and that it is chemically inert. Specific examples include a direct bond, a sulfonyl group, an alkylene group, a divalent condensed polycyclic structure, a divalent hydrocarbon group containing an ether bond, a direct bond, an ether bond, a sulfide bond, a carbonyl group, a carboxylic acid ester bond, an amide bond, a urea bond, a urethane bond, a carbonate ester bond, a cycloalkylene group, an arylene group, a divalent condensed polycyclic heterocyclic structure, a divalent hydrocarbon group containing a carbonyloxy group, or a divalent hydrocarbon group containing a carbonylamide group. From the viewpoint of achieving high sensitivity, X is preferably a sulfonyl group, an alkylene group, an ether bond, a sulfide bond, or a cycloalkylene group, and more preferably an alkylene group.

[0055] The most preferred structure of X is as follows:

[0056]

[0057] * indicates the point of attachment.

[0058] In the formula (1), V represents a straight-chain or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms or a divalent aliphatic hydrocarbon group represented by formula (9).

[0059]

[0060] In formula (9), n represents an integer of 0 to 11, and m represents an integer of 1 to 12, provided that n+m is 1 to 12. R ２０ and R ２１ represents a hydrocarbon group having 2 to 4 carbon atoms when n=0, and represents a hydrocarbon group having 1 to 4 carbon atoms when n≠0. * represents the point of attachment to the amide group.

[0061] In the interpretation of the meaning of the above formula (9), —CH ２ - and - (CR ２０ R ２１ )- are not necessarily bonded consecutively, and in formula (9), ２ - is n pieces, -(CR ２０ R ２１ For example, the divalent aliphatic hydrocarbon group represented by formula (9) is a group represented by the formula (9) ２ -C(CH ３ ) ２ -CH ２ - (in this case, n is 2 and m is 1).

[0062] When V in formula (1) contains a divalent aliphatic hydrocarbon group represented by formula (9), it is possible to suppress the fluidity of the polymer during curing and reduce shrinkage of the pattern.

[0063] From the viewpoint of minimizing shrinkage of the pattern, n+m is preferably an integer of 1 to 6, and more preferably an integer of 1 to 3.

[0064] R ２０ and R ２１ Preferred specific examples of n include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a t-butyl group when n=0, and an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a t-butyl group when n=non-0.

[0065] More preferred structures for the divalent aliphatic hydrocarbon group represented by formula (9) include the following structures:

[0066]

[0067] In the formula, * represents the point of attachment to the amide group.

[0068] From the viewpoint of suppressing the fluidity of the polymer during curing and reducing pattern shrinkage during hardening, V is more preferably a straight-chain or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms.

[0069] Preferred specific examples of the straight-chain or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms include residues of malonic acid, dimethylmalonic acid, succinic acid, methylsuccinic acid, and glutaric acid.

[0070] From the viewpoint of reducing pattern shrinkage during curing, V is most preferably a divalent group represented by formula (3).

[0071]

[0072] In formula (3), R ５ and R ６ each independently represents a hydrogen atom or a methyl group. * represents the point of attachment to the amide group.

[0073] From the viewpoint of reducing pattern shrinkage during reflow curing, ５ and R ６ At least one of these is preferably a methyl group, and more preferably both are methyl groups.

[0074] <Component (a) Having a Repeating Unit Represented by Formula (2)> From the viewpoint of achieving high sensitivity, the component (a) used in the photosensitive resin composition of the present invention preferably contains a repeating unit represented by formula (2) in addition to the repeating unit represented by formula (1).

[0075]

[0076] In formula (2), R ３ and R ４each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. ３ and -OR ４ is bonded to the ortho position relative to an amide bond bonded to the same aromatic ring or to a carbon adjacent to the carbon to which the amide bond is bonded.

[0077] R ３ and R ４ Preferred examples of R １ and R ２ The meaning of the acid-decomposable group and the meaning of the terms used when an acid-decomposable group is used are the same as those explained in the explanation for formula (1).

[0078] Y represents a divalent linking group, and has the same meaning as the divalent linking group used for X in formula (1), and therefore the same explanation is incorporated herein.

[0079] Preferable examples of Y are the same as those explained for X in formula (1), and therefore the explanation therefor is incorporated herein by reference.

[0080] U represents a divalent aliphatic hydrocarbon group having 3 to 30 carbon atoms and containing an alicyclic skeleton, or a linear or branched divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms (excluding groups corresponding to the divalent aliphatic hydrocarbon group represented by formula (9) above).

[0081] From the viewpoint of achieving high sensitivity by improving the dissolution rate of the exposed area, it is preferable to increase the concentration of phenolic hydroxyl groups contained in one molecule of component (a), and as one means for achieving this, U is preferably a divalent aliphatic hydrocarbon group having 3 to 10 carbon atoms and containing an alicyclic structure, and more preferably a divalent aliphatic hydrocarbon group having 3 to 5 carbon atoms and containing an alicyclic structure.

[0082] Specific examples of the alicyclic structure include, but are not limited to, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, dimethylcyclohexane, dimethylcyclobutane, and tetramethylcyclohexane.

[0083] From the viewpoint of improving sensitivity, the component (a) used in the present invention preferably contains 1 mol % or more, more preferably 20 mol % or more, and even more preferably 30 mol % or more of the repeating units represented by formula (2) when the total of the repeating units represented by formula (1) and the repeating units represented by formula (2) is taken as 100 mol %. Also, from the viewpoint of improving sensitivity, the component (a) preferably contains 80 mol % or less, more preferably 70 mol % or less of the repeating units represented by formula (2) when the total of the repeating units represented by formula (1) and the repeating units represented by formula (2) is taken as 100 mol %.

[0084] <Component (a) Having Other Repeating Units> From the viewpoint of improving the taper angle of the pattern after curing and forming a high-density pattern, the component (a) used in the photosensitive resin composition of the present invention preferably contains a repeating unit represented by formula (11) in addition to the repeating unit represented by formula (1).

[0085]

[0086] In formula (11), R ２４ and R ２５ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. ２４ and -OR ２５ is bonded to the ortho position relative to an amide bond bonded to the same aromatic ring or to a carbon adjacent to the carbon to which the amide bond is bonded.

[0087] R ２４ and R ２５ Preferred examples of R １ and R ２ The meaning of the acid-decomposable group and the meaning of the terms used when an acid-decomposable group is used are the same as those explained in the explanation for formula (1).

[0088] W represents a divalent linking group, and has the same meaning as the divalent linking group used for X in formula (1), and therefore the same explanation is incorporated herein.

[0089] Preferable examples of W are the same as those explained for X in formula (1), and therefore the explanation therefor is incorporated herein by reference.

[0090] Z represents a divalent aromatic group having 6 to 30 carbon atoms. Preferred structures of the aromatic group include the following: These aromatic groups may have a substituent, such as an aliphatic hydrocarbon group, as long as the substituent does not affect the function of the photosensitive resin composition.

[0091]

[0092] In the formula, * represents the point of attachment to the amide group.

[0093] From the viewpoint of improving the taper angle of the pattern after curing and forming a high-density pattern, the component (a) used in the present invention preferably contains 1 mol % or more of the repeating unit represented by formula (1), the repeating unit represented by formula (2), and the repeating unit represented by formula (11) when the total of the repeating unit represented by formula (1), the repeating unit represented by formula (2), and the repeating unit represented by formula (11) is taken as 100 mol % (note that the repeating unit represented by formula (2) may not be included). The component (a) preferably contains 1 mol % or more of the repeating unit represented by formula (11), more preferably 2 mol % or more, and even more preferably 5 mol % or more. Furthermore, from the viewpoint of improving sensitivity, the component (a) preferably contains less than 15 mol %, more preferably 12 mol % or less, and even more preferably 10 mol % or less of the repeating unit represented by formula (11), when the total of the repeating unit represented by formula (1), the repeating unit represented by formula (2), and the repeating unit represented by formula (11) is taken as 100 mol %.

[0094] By using the repeating unit represented by formula (11) in combination with the repeating unit represented by formula (1), deformation due to reflow during curing can be further reduced, and the taper angle of the pattern after curing is significantly improved compared to when the repeating unit is used in combination with a repeating unit other than formula (1).

[0095] The polybenzoxazole precursor used in the present invention can be synthesized by known methods. For example, it can be obtained by reacting a bisaminophenol compound with a dicarboxylic acid or the corresponding dicarboxylic acid chloride or dicarboxylic acid activated ester. In the polybenzoxazole precursor component (a), the repeating units represented by formulas (1), (2), and (11) account for 70 mol% or more, preferably 80 mol% or more, and particularly preferably 90 mol% or more of the total repeating units, with the upper limit being 100 mol% (note that the repeating units represented by formulas (2) and (11) may not be included). Furthermore, the polybenzoxazole precursor component (a) may contain other α-hydroxy(alkyl or hydrogen)arylamide structures in addition to the repeating units represented by formulas (1), (2), and (11). Furthermore, copolymerizable repeating units other than the α-hydroxy(alkyl or hydrogen)arylamide structure may be contained in an amount of less than 30 mol %, preferably 20 mol % or less, and more preferably 10 mol % or less of the total repeating units.

[0096] The photosensitive resin composition of the present invention may contain a polybenzoxazole precursor other than component (a) or other polymer component within the range that does not impair the object of the present invention. The amount of the polybenzoxazole precursor or other polymer component is preferably 35% by mass or less, more preferably 25% by mass or less, and even more preferably 15% by mass or less, when the mass of the solid content of the photosensitive resin composition is taken as 100% by mass.

[0097] The main chain terminals of the component (a) used in the present invention may be capped with a terminal capping agent such as a monoamine, an acid anhydride, a monocarboxylic acid, a monoacid chloride compound, a monoactive ester compound, etc. By capping the main chain terminals with a terminal capping agent, the storage stability of the photosensitive resin composition can be improved.

[0098] The component (a) used in the present invention preferably has a thermally crosslinkable group or a monovalent hydrocarbon group having a thermally crosslinkable group at its terminal structure, from the viewpoints of suppressing the fluidity of the polymer during curing and reducing pattern shrinkage during curing.

[0099] Specific examples of the thermally crosslinkable group include, but are not limited to, a methylol group, an alkoxymethyl group, a vinyl group, an ethynyl group, an epoxy group, a glycidyl group, an oxetanyl group, an acryl group, and a methacryl group.

[0100] Preferred are vinyl groups, acrylic groups and methacrylic groups, and more preferred are acrylic groups and methacrylic groups.

[0101] By having a thermally crosslinkable group in the terminal structure of component (a), deformation due to reflow during curing can be further reduced, and the taper angle of the pattern after curing is significantly improved compared to when a resin other than component (a) has a thermally crosslinkable group in its terminal structure.

[0102] The introduction ratio of the monoamine used as the end-capping agent is preferably 20 mol% or more, more preferably 40 mol% or more, even more preferably 60 mol% or more, and particularly preferably 75 mol% or more, based on the amount of terminal carboxyl groups contained in component (a) taken as 100 mol%. Furthermore, the introduction ratio of the acid anhydride, monocarboxylic acid, monoacid chloride compound, or monoactive ester compound used as the end-capping agent is preferably 20 mol% or more, more preferably 40 mol% or more, even more preferably 60 mol% or more, particularly preferably 75 mol% or more, based on the amount of terminal amino groups contained in component (a) taken as 100 mol%. Multiple different end groups may be introduced by reacting multiple end-capping agents.

[0103] The weight-average molecular weight of component (a), as measured by gel permeation chromatography, is preferably 3,000 to 200,000, more preferably 5,000 to 100,000, and even more preferably 7,000 to 60,000, in terms of polystyrene. By setting the weight-average molecular weight of component (a) within the above range, it becomes easier to achieve good solvent solubility, good solubility in a developer, and high mechanical strength. Specific methods for measuring the weight-average molecular weight are as described in the Examples section.

[0104] <Photoacid Generator ((b) Photoacid Generator)> The photoacid generator used in the present invention is a compound having a function of generating an acid upon exposure to light. Any known photoacid generator can be used as long as it does not impair the effects of the present invention.

[0105] Specific examples of photoacid generators include ester compounds of polyhydric phenol compounds and naphthoquinone diazide sulfonic acid compounds, onium salt-type ionic photoacid generators, and nonionic photoacid generators. An onium salt is a compound formed when a compound having an electron pair not involved in a chemical bond forms a coordinate bond with another cationic compound via that electron pair. The cation portion of the onium salt determines the photochemical properties (molar absorption coefficient, absorption wavelength, and quantum yield), while the anion portion determines the strength of the acid generated. On the other hand, nonionic photoacid generators are photoacid generators in which the light-absorbing portion and the acid are connected via an ester bond.

[0106] The ionic photoacid generator is preferably one that does not contain heavy metals or halogen ions, and more preferably a triorganosulfonium salt compound. Specific examples of the triorganosulfonium salt compound include triphenylsulfonium methanesulfonate, trifluoromethanesulfonate, camphorsulfonate, 4-toluenesulfonate, and perfluoro-1-butanesulfonate ("SP-056", product name, manufactured by ADEKA Corporation); the sulfonates of dimethyl-1-naphthylsulfonium; the sulfonates of dimethyl(4-hydroxy-1-naphthyl)sulfonium; the sulfonates of dimethyl(4,7-dihydroxy-1-naphthyl)sulfonium; and the sulfonates of diphenyliodonium.

[0107] As the nonionic photoacid generator, diazomethane compounds, sulfone compounds, sulfonate compounds, carboxylate compounds, sulfonimide compounds, phosphate compounds, sulfonebenzotriazole compounds, etc. can be used.

[0108] A specific example of the diazomethane compound is bis(4-methylphenylsulfonyl)diazomethane ("WPAG-199", trade name, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0109] Specific examples of the sulfone compound include β-ketosulfone compounds, β-sulfonylsulfone compounds, etc. Preferred examples of the sulfone compound include 2-(p-toluenesulfonyl)acetophenone and bis(phenylsulfonyl)methane.

[0110] Specific examples of the sulfonate ester compound include alkylsulfonate esters, haloalkylsulfonate esters, arylsulfonate esters, iminosulfonate ester compounds, etc. Preferred specific examples include benzoin-4-tolyl sulfonate, pyrogallol tris(methylsulfonate), nitrobenzyl-9,10-diethoxyanthryl-2-sulfonate, and 2,6-(dinitrobenzyl)phenyl sulfonate.

[0111] Specific examples of carboxylic acid ester compounds include carboxylic acid 2-nitrobenzyl esters.

[0112] In the photosensitive resin composition of the present invention, the content of the photoacid generator (b) is preferably 1 to 100 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of component (a), in terms of the difference in dissolution rate between exposed and unexposed areas and the tolerance range of sensitivity.

[0113]

[0043] The photosensitive resin composition of the present invention preferably contains a thermal crosslinking agent, from the viewpoint of improving the taper angle of the cured pattern and forming a high-density pattern. Examples of the thermal crosslinking agent include those containing two or more thermal crosslinkable groups in the molecule.

[0114] From the viewpoint of further improving the taper angle, the number of thermally crosslinkable groups contained in the molecule of the thermal crosslinking agent is preferably 5 or more. That is, it is preferable that all or a part of the thermal crosslinking agent is a thermal crosslinking agent having 5 or more thermally crosslinkable groups.

[0115] Specific examples of the thermal crosslinkable group include a methylol group, an alkoxymethyl group, a vinyl group, an ethynyl group, an epoxy group, a glycidyl group, and an oxetanyl group. Of these, the thermal crosslinking agent preferably has a methylol group or an alkoxymethyl group, more preferably an alkoxymethyl group.

[0116] Examples of the alkoxymethyl group include a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, and a butoxymethyl group.

[0117] Preferred examples of such compounds include HMOM-TPPHBA and HMOM-TPHAP (trade names, manufactured by Honshu Chemical Industry Co., Ltd.), NIKALAC (registered trademark) MX-290, NIKALAC MX-280, NIKALAC MX-270, NIKALAC MX-279, NIKALAC MW-100LM, and NIKALAC MX-299. MX-750LM (trade names, manufactured by Sanwa Chemical Co., Ltd.), VG3101L (trade name, manufactured by Printec Co., Ltd.), "TEPIC" (registered trademark) S, "TEPIC" G, "TEPIC" P (trade names, manufactured by Nissan Chemical Industries, Ltd.), "Epiclon" N660, "Epiclon" N695, HP7200 (trade names, manufactured by Dainippon Ink and Chemicals, Inc.), "Denacol" EX-321L (trade name, manufactured by Nagase ChemteX Corporation), NC6000, EPPN502H, NC3000 (trade names, manufactured by Nippon Ink and Chemicals, Inc.), Examples of compounds having an oxetanyl group include OXT-121, OXT-221, OX-SQ-H, OXT-191, PNOX-1009, and RSOX (all trade names, manufactured by Toa Gosei Co., Ltd.), "Etanacol" (registered trademark) OXBP, and "Etanacol" OXTP (all trade names, manufactured by Ube Industries, Ltd.), and can be obtained from the respective companies.

[0118] In the photosensitive resin composition of the present invention, the content of the thermal crosslinking agent is preferably 5 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the amount of component (a). By making the content of the thermal crosslinking agent 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, relative to 100 parts by mass of the amount of component (a), pattern shrinkage during curing is reduced. Furthermore, by making the content of the thermal crosslinking agent 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the amount of component (a), a decrease in the elongation of the cured product can be prevented.

[0119] By using a thermal crosslinking agent in combination with component (a), deformation due to reflow during curing can be further reduced, and the taper angle of the pattern after curing is significantly improved compared to when component (a) is not used in combination.

[0120] <Compound Represented by Formula (10)> From the viewpoint of being able to reduce the change in sensitivity depending on the time from exposure to development, the photosensitive resin composition of the present invention preferably does not substantially contain a compound represented by formula (10), and even if it does contain one, the content thereof is preferably 0.3% by mass or less when the total amount of the photosensitive resin composition is taken as 100% by mass. Here, the meaning of "substantially" means that it is below the detection limit in the measurement method described in the Examples section.

[0121]

[0122] In formula (10), R ２２ represents a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms. From the viewpoint of film shrinkage during curing, R ２２ The effect is more pronounced when the group is a methyl group or an ethyl group, and more pronounced when the group is a methyl group.

[0123] In formula (10), R ２３ When a plurality of R are present, each independently represents a monovalent organic group having 1 to 12 carbon atoms. ２３ When the group is a methyl group, an ethyl group, a propyl group, an isopropyl group, or a butyl group, the effect on the sensitivity change is large, the effect is more pronounced when the group is a methyl group or an ethyl group, and the effect is even more pronounced when the group is a methyl group.

[0124] In formula (10), s is 2 or 3. When considering the compatibility with component (a) and the effect on film shrinkage during curing, an s of 2 has a greater effect.

[0125] In formula (10), t represents an integer that satisfies 0≦t≦(s+1). From the viewpoint of suppressing shrinkage of the film during curing, t is preferably 0.

[0126] Examples of the compound represented by formula (10) include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methyl-2-piperidone, N-ethyl-2-piperidone, and 1,5-dimethyl-2-piperidone.

[0127] From the viewpoint of being able to reduce a change in sensitivity due to the elapsed time from exposure to development, the content of the compound represented by formula (10) contained in the photosensitive resin composition is 0.1% by mass or less, more preferably 0.01% by mass or less, even more preferably 0.005% by mass or less, and most preferably 0% by mass, when the total amount of the photosensitive resin composition is 100% by mass.

[0128] The present inventors have found that, while the compound represented by formula (10) is often used as a general-purpose solvent in polymer polymerization and the like, when the compound represented by formula (10) coexists with component (a) having reduced skeletal flexibility in order to suppress fluidity during curing, the change in sensitivity with respect to the time from exposure to development becomes greater than when the compound represented by formula (10) coexists with a flexible polymer.

[0129] From this viewpoint, it is preferable not to use the compound represented by formula (10) during synthesis of the polymer or during preparation of the photosensitive resin composition.

[0130] <Other Components> The photosensitive resin composition of the present invention may contain components other than component (a) and (b) the photoacid generator, to the extent that the object of the present invention is not impaired or for the purpose of imparting additional functions. Such components include a resin other than a polybenzoxazole precursor or a precursor thereof, a solvent, an amine compound, a dissolution accelerator, a sensitizer, a silane coupling agent, and a surfactant.

[0131] <Solvent> The positive photosensitive resin composition of the present invention preferably further contains a solvent (hereinafter, may be referred to as "(c) solvent"). By containing a solvent, the coating property is improved, and a homogeneous positive photosensitive resin film can be obtained. Any known (c) solvent can be used as long as it does not impair the effects of the present invention.

[0132] The (c) solvent is not particularly limited as long as it can dissolve or disperse the (a) component and the (b) photoacid generator, but suitable solvents include amide-based solvents, ester-based solvents, alcohol-based solvents, ether-based solvents, ketone-based solvents, and dimethyl sulfoxide.

[0133] Specific examples of amide solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutyric acid amide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and N,N-dimethylpropylene urea.

[0134] Specific examples of ester solvents include γ-butyrolactone, δ-valerolactone, propylene carbonate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, propylene glycol monomethyl ether acetate, 3-methoxy-1-butyl acetate, 3-methyl-3-methoxy-1-butyl acetate, ethyl acetoacetate, and cyclohexanol acetate.

[0135] Specific examples of alcohol-based solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 3-hydroxy-3-methyl-2-butanone, 5-hydroxy-2-pentanone, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethyl lactate, butyl lactate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-n-butyl ether, propylene glycol mono-t-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, 3-methoxy-1-butanol, 3-methyl-3-methoxy-1-butanol, ethylene glycol, and propylene glycol.

[0136] Specific examples of ether solvents include diethyl ether, diisopropyl ether, di-n-butyl ether, diphenyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, and dipropylene glycol dimethyl ether.

[0137] Specific examples of ketone solvents include methyl isobutyl ketone, diisopropyl ketone, diisobutyl ketone, acetylacetone, cyclopentanone, cyclohexanone, cycloheptanone, and dicyclohexyl ketone.

[0138] The (c) solvent preferably contains an aprotic solvent having a relative dielectric constant in the range of 5 to 20, more preferably 6 to 19, and even more preferably 7 to 19.

[0139] (c) When the solvent contains an aprotic solvent having a relative dielectric constant in the range of 5 to 20, the storage stability of the positive photosensitive resin composition as a solution is improved.

[0140] Examples of aprotic solvents having a dielectric constant in the range of 5 to 20 include tetrahydrofuran (dielectric constant 7.6), propylene glycol monomethyl ether acetate (dielectric constant 8.3), methyl isobutyl ketone (dielectric constant 13.1), cyclopentanone (dielectric constant 14.5), cyclohexanone (dielectric constant 18.3), and methyl ethyl ketone (dielectric constant 18.5).

[0141] The (c) solvent is preferably an aprotic solvent having 3 to 12 carbon atoms, and the number of carbon atoms of such an aprotic solvent is more preferably 4 to 10. An aprotic solvent having 3 to 12 carbon atoms has excellent solubility for the component (a) used in the positive photosensitive resin composition of the present invention. Therefore, by using an aprotic solvent having 3 to 12 carbon atoms in the photosensitive resin composition of the present invention, the solids concentration of the photosensitive resin composition can be increased, and by coating a composition containing such a solvent, it becomes easy to obtain a film of the photosensitive resin composition with a large thickness, for example, a thickness of 1 μm or more.

[0142] In the present invention, the content of the (c) solvent is preferably 100 parts by mass or more per 100 parts by mass of the (a) component in order to enhance the stability of the solution, while the content is preferably 1,500 parts by mass or less in order to form a thick film of the photosensitive resin composition, specifically a film with a thickness of 1 μm or more.

[0143] <Amine Compound> The photosensitive resin composition of the present invention preferably further contains an amine compound (hereinafter, may be referred to as "(d) amine compound"). By containing the (d) amine compound, deprotection is suppressed during pre-baking, which will be described later. Therefore, a pattern of the photosensitive resin composition can be obtained with little reduction in the developed film.

[0144] As the (d) amine compound, it is preferable to use an amine compound whose conjugate acid has a pKa in the range of 4.5 to 10.8, more preferably an amine compound whose pKa is 5.0 to 10.0, and even more preferably an amine compound whose pKa is 6.0 to 9.0. When the pKa of the conjugate acid of the (d) amine compound is in the above range, deprotection during pre-baking is suppressed and acid generated during exposure is less likely to be neutralized, making it possible to obtain a photosensitive resin composition pattern with little film loss upon development.

[0145] Examples of amine compounds having a conjugate acid with a pKa in the above range include aniline (pKa=4.6), dimethylaniline (pKa=5.20), pyridine (pKa=5.25), 2-picoline (pKa=5.97), 2,6-lutidine (pKa=6.75), imidazole (pKa=6.95), N-methylmorpholine (pKa=7.38), morpholine (pKa=8.36), dicyclohexylamine (pKa=10.4), and cyclohexylamine (pKa=10.6).

[0146] In the present invention, the content of the (d) amine compound is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the (a) component. When the content of the (d) amine compound is within the above range, a highly sensitive photosensitive resin composition pattern with little film loss can be obtained.

[0147] <Fluorine Atom Content> In the photosensitive resin composition of the present invention, the content of fluorine atoms contained in the resin is preferably less than 5% by mass, when the total mass of the resins contained in the photosensitive resin composition is taken as 100% by mass. When the content of fluorine atoms contained in the resin is less than 5% by mass, the hydrophobicity of the photosensitive resin composition is reduced. This increases the affinity for the developer and suppresses the generation of residues, thereby achieving high sensitivity.

[0148] The content of fluorine atoms contained in the resin when the total amount of the resin contained in the photosensitive resin composition is taken as 100 mass % can be analyzed by the following method.

[0149] First, the resin is separated from the photosensitive resin composition. The separated resin is precisely weighed as a sample. Using an automatic sample combustion device, the resin is burned in the combustion tube of an analyzer. The generated gas is absorbed into a solution, and a portion of the absorbed solution is analyzed by ion chromatography. 0.036% by mass of hydrogen peroxide water can be used as the absorbed solution. Specific measurement methods are as described in the Examples section.

[0150] <Photosensitive Resin Sheet> The photosensitive resin composition of the present invention is not limited in its form, and may be in the form of, for example, a solution, a paste, or a sheet.

[0151] The photosensitive resin sheet of the present invention is obtained by forming the photosensitive resin composition of the present invention into a film on a support.

[0152] A specific method for obtaining the photosensitive resin sheet of the present invention includes, for example, applying a solvent-containing photosensitive resin composition to a support, drying the composition at a temperature and for a time within a range that allows the solvent to volatilize, and forming the composition into a sheet film while the component (a) is not completely cured. From this viewpoint, it is preferable that the components other than the organic solvent used in the photosensitive resin composition of the present invention are soluble in a solvent, particularly an organic solvent.

[0153] The support used in the photosensitive resin sheet is not particularly limited, but various commercially available films such as polyethylene terephthalate (PET) film, polyphenylene sulfide film, and polyimide film can be used. The contact surface between the support and the photosensitive resin composition may be surface-treated with silicone, a silane coupling agent, an aluminum chelating agent, polyurea, or the like to improve adhesion and release properties. The thickness of the support is not particularly limited, but is preferably in the range of 10 to 100 μm from the viewpoint of workability. Furthermore, a protective film may be provided on the film surface to protect the surface of the photosensitive resin composition film obtained by coating. This protects the surface of the photosensitive resin composition film from contaminants such as dust and dirt in the atmosphere.

[0154] Examples of methods for applying the photosensitive resin composition to a support include spin coating using a spinner, spray coating, roll coating, screen printing, a blade coater, a die coater, a calendar coater, a meniscus coater, a bar coater, a roll coater, a comma roll coater, a gravure coater, a screen coater, and a slit die coater. The film thickness after application varies depending on the application technique, the solids concentration of the composition, the viscosity, etc., but it is usually preferable that the film thickness after drying be 0.5 μm or more and 100 μm or less from the viewpoint of coating film uniformity, etc.

[0155] When a solvent is used, drying can be performed using an oven, a hot plate, infrared rays, or the like. The drying temperature and drying time may be within a range that allows the solvent to volatilize, and are preferably set appropriately within a range that allows the photosensitive resin composition to be in an uncured or semi-cured state. Specifically, drying is preferably performed within a range of 40°C to 150°C for 1 minute to several tens of minutes. Alternatively, the temperature may be increased stepwise using a combination of these temperatures; for example, heat treatment may be performed at 80°C and 90°C for 2 minutes each.

[0156] <Cured Product> The cured product of the present invention is obtained by curing the photosensitive resin composition of the present invention. That is, curing refers to conversion of a polybenzoxazole precursor into polybenzoxazole.

[0157] As for the curing conditions, a temperature of 150°C to 320°C is applied to promote the thermal crosslinking reaction, improving heat resistance and chemical resistance. This heat treatment can be carried out by selecting a temperature and increasing the temperature stepwise, or by selecting a temperature range and continuously increasing the temperature for 5 minutes to 5 hours. As an example, heat treatment is carried out at 130°C and 200°C for 30 minutes each. In the present invention, the lower limit of the curing conditions is preferably 170°C or higher, but 170°C or higher is more preferable in order to promote sufficient curing. The upper limit of the curing conditions is preferably 280°C or lower.

[0158] The method for obtaining a patterned cured film will be described below by taking two typical embodiments as examples.

[0159] <Method for Producing Patterned Cured Film (1)> One embodiment of the method for producing a cured film on a substrate of the present invention includes the steps of: preparing a substrate; and forming the photosensitive resin composition of the present invention into a film on the substrate; exposing the film of the photosensitive resin composition to light to form a latent image in the film; developing the exposed film of the photosensitive resin composition with an alkaline aqueous solution; and curing the developed film of the photosensitive resin composition.

[0160] The patterned cured product obtained in this manner is a cured product mainly composed of polybenzoxazole, and therefore has excellent heat resistance, electrical insulation properties, and mechanical properties.

[0161] The method for producing a cured product of the present invention includes the steps of preparing a substrate and forming the photosensitive resin composition of the present invention into a film on the substrate.

[0162] The substrate on which the cured film is formed is not particularly limited, but is preferably selected from the group consisting of glass, silicon wafer, ceramic deposition substrate, metal-plated substrate, sapphire, and gallium arsenide. Furthermore, electrical parts or elements such as electrical wiring, electrodes, semiconductor elements, and pixels made of light-emitting materials may be formed on these substrates.

[0163] The photosensitive composition of the present invention can be applied to a substrate by any known method, including, for example, a full-surface coating apparatus such as spin coating, dip coating, curtain flow coating, spray coating, or slit coating, or a printing apparatus such as screen printing, roll coating, microgravure coating, or inkjet printing.

[0164] After coating, a drying step is carried out to remove the solvent, forming a film of dried photosensitive resin composition. Drying is carried out using a vacuum drying device or a heating device such as a hot plate or oven. When using a heating device, drying is preferably carried out at a temperature range of 50°C to 150°C for 30 seconds to 30 minutes. The film thickness of the dried photosensitive resin composition is preferably 0.1 mm to 100 μm.

[0165] The method for producing a cured product of the present invention includes a step of exposing the dried film of the photosensitive resin composition to light to form a latent image in the film.

[0166] In the exposure step, the film-form photosensitive resin composition is exposed through a mask having a desired pattern to form a latent image. The wavelength of the exposure light is not particularly limited, and examples include light having a wavelength of 300 to 450 nm, such as g-line (436 nm), i-line (365 nm), and h-line (405 nm). Of these, light having a wavelength of 365 nm is preferred. Examples of light sources used in the exposure step include various lasers, light-emitting diodes (LEDs), ultra-high pressure mercury lamps, high-pressure mercury lamps, low-pressure mercury lamps, and metal halide lamps. Furthermore, the wavelength of the irradiated light may be adjusted, if necessary, through a spectral filter such as a long-wavelength cut filter, a short-wavelength cut filter, or a bandpass filter.

[0167] After exposure, post-exposure baking may be performed as necessary. By performing post-exposure baking, effects such as improved resolution after development or an increased tolerance for development conditions can be expected. For post-exposure baking, an oven, a hot plate, infrared radiation, a flash annealing device, a laser annealing device, or the like can be used. The post-exposure baking temperature is preferably 50 to 170°C, more preferably 60 to 150°C. The post-exposure baking time is preferably 10 seconds to 1 hour, more preferably 30 seconds to 30 minutes.

[0168] The method for producing a cured product of the present invention includes a step of developing the exposed photosensitive resin composition film with an alkaline aqueous solution.

[0169] To form a pattern of the photosensitive resin composition, after exposure, the exposed area is removed using a developer. The developer used for development is typically an alkaline aqueous solution in which an alkaline compound is dissolved. Examples of alkaline compounds include tetramethylammonium hydroxide, potassium hydroxide, and sodium carbonate. In some cases, polar solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, γ-butyrolactone, and dimethylacrylamide; alcohols such as methanol, ethanol, and isopropanol; esters such as ethyl lactate and propylene glycol monomethyl ether acetate; and ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, and methyl isobutyl ketone may be added, either alone or in combination, to these alkaline aqueous solutions.

[0170] After development, it is preferable to perform a rinse treatment with an organic solvent or water. When an organic solvent is used, in addition to the above-mentioned developer, examples of the organic solvent include ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate. When water is used, a hydrophilic organic solvent such as an alcohol such as ethanol or isopropyl alcohol, or an ester such as ethyl lactate or propylene glycol monomethyl ether acetate may be added to the water for rinsing treatment.

[0171] The method for producing a cured product of the present invention includes a step of curing the developed film of the photosensitive resin composition.

[0172] After development, a temperature of 150°C to 320°C is applied to convert the polybenzoxazole precursor to polybenzoxazole, and if a crosslinking agent is used, a thermal crosslinking reaction is promoted, improving heat resistance and chemical resistance. This heat treatment is carried out by selecting a temperature and gradually increasing the temperature, or by selecting a temperature range and continuously increasing the temperature for 5 minutes to 5 hours. As an example, heat treatment is carried out at 130°C and 200°C for 30 minutes each. In the present invention, the lower limit of the curing conditions is preferably 170°C or higher, but more preferably 180°C or higher to promote sufficient curing. The upper limit of the curing conditions is preferably 280°C or lower.

[0173] <Method for producing a patterned cured product film (2)> Another embodiment of the method for producing a cured product film on a substrate of the present invention includes the steps of: pressing the photosensitive resin sheet of the present invention onto a substrate, and peeling off the support or protective film used in the photosensitive resin sheet to transfer the film-like photosensitive resin composition onto the base material; exposing the transferred photosensitive resin composition to light to form a latent image in the film of photosensitive resin composition; developing the exposed film of photosensitive resin composition with an alkaline aqueous solution; and curing the developed film of photosensitive resin composition.

[0174] However, in this manufacturing method, the support or protective film used in the photosensitive resin sheet may be peeled off after exposure.

[0175] The patterned cured product obtained in this manner is a cured product mainly composed of polybenzoxazole, and therefore has excellent heat resistance, electrical insulation properties, and mechanical properties.

[0176] The substrate on which the cured film is formed is not particularly limited, but it is the same as that described in the section (1) of the method for producing a patterned cured film, and for example, silicon wafer, ceramics, gallium arsenide, organic circuit board, inorganic circuit board, and the substrate on which the circuit constituent material is arranged.Examples of organic circuit boards include glass substrate copper-clad laminates such as glass cloth / epoxy copper-clad laminates, composite copper-clad laminates such as glass nonwoven cloth / epoxy copper-clad laminates, heat-resistant / thermoplastic substrates such as polyetherimide substrates, polyetherketone substrates, polysulfone substrates, flexible substrates such as polyester copper-clad film substrates, polyimide copper-clad film substrates.In addition, examples of inorganic circuit boards include ceramic substrates such as alumina substrates, aluminum nitride substrates, silicon carbide substrates, and metal substrates such as aluminum-based substrates, iron-based substrates. Examples of materials constituting the circuit include conductors containing metals such as silver, gold, and copper, resistors containing inorganic oxides, low dielectrics containing glass-based materials and / or resins, high dielectrics containing resins and high-dielectric-constant inorganic particles, and insulators containing glass-based materials.

[0177] The process of bonding the photosensitive resin sheet to the substrate is not particularly limited, but thermocompression bonding is preferably used, and known methods can be used. For example, when the photosensitive resin sheet has a protective film, the support is peeled off while leaving the protective film, and the photosensitive resin composition with the protective film is placed face to face with the substrate and bonded by thermocompression bonding. Thermocompression bonding can be performed by heat pressing, heat lamination, thermal vacuum lamination, etc. Among these, thermal lamination is preferred. The bonding temperature is preferably 40°C or higher in terms of adhesion to the substrate and embeddability. Furthermore, to prevent the resin composition film from curing during bonding, which would deteriorate the resolution of pattern formation in the exposure and development steps, the bonding temperature is preferably 150°C or lower.

[0178] The photosensitive resin sheet pressed onto the substrate is subjected to a process in which the support and protective film, if any, are peeled off, and the photosensitive resin composition film on the substrate is exposed to light, the exposed portion of the exposed photosensitive resin composition film is developed by eluting or removing it with an alkaline aqueous solution, and the developed photosensitive resin composition film is cured. These processes are not particularly limited, but are preferably carried out in the same manner as in the method (1) for producing a patterned cured film.

[0179] <Elements and articles including the cured product> The cured product of the present invention can be used, for example, in electronic components and electronic devices. Examples of electronic components include semiconductor devices, antennas, display devices, metal-clad laminates, wiring boards, semiconductor packages, active components including semiconductor devices, and passive components. Examples of display devices include organic electroluminescence displays, quantum dot displays, micro light-emitting diode (hereinafter referred to as "LED") displays, mini-LED displays, and liquid crystal displays.

[0180] The film can also be suitably used as an interlayer insulating film between rewirings on a substrate on which semiconductor or LED chips are mounted.

[0181] <Semiconductor Device> The cured product obtained by curing the photosensitive resin composition of the present invention can be used in electronic components such as semiconductor devices. In the present invention, the term "semiconductor device" refers to any device that can function by utilizing the characteristics of a semiconductor element. Semiconductor devices include electro-optical devices in which semiconductor elements are connected to a substrate, semiconductor circuit boards, stacks of multiple semiconductor elements, and electronic devices containing these. Semiconductor devices also include electronic components such as interposers for connecting semiconductor elements to a substrate. Specifically, the cured product obtained by curing the photosensitive resin composition of the present invention has excellent electrical insulation, mechanical strength, adhesion, and heat resistance. Therefore, semiconductor devices in which these are used as surface protection films such as passivation films and buffer coat films for semiconductor elements, interlayer insulating films between rewirings formed on the surface of semiconductor elements, insulating films between elements when multiple semiconductor elements are bonded, and insulating films between wiring layers of multilayer wiring boards for high-density packaging or interposers are preferred.

[0182] More preferably, the photosensitive resin composition of the present invention is cured and disposed as a semiconductor surface protective film or an interlayer insulating film between rewirings in a semiconductor device. By disposing a cured film of the photosensitive composition as a semiconductor surface protective film or an interlayer insulating film between rewirings, a highly reliable semiconductor device can be obtained.

[0183] More preferably, the semiconductor device has the rewiring and the interlayer insulating film repeatedly arranged in 2 to 10 layers. By repeatedly arranging the rewiring and the interlayer insulating film in 2 to 10 layers, the semiconductor device can be miniaturized.

[0184] <Display Device> The display device of the present invention is a display device including a first electrode formed on a substrate, an insulating layer formed on the first electrode so as to define pixels, and a second electrode provided opposite the first electrode, wherein the insulating layer is the cured product of the present invention. The insulating layer can be formed by applying and drying the photosensitive resin composition of the present invention onto a substrate on which the first electrode has been formed, or by laminating a sheet-like photosensitive resin composition, and then going through the steps of exposure, development, and curing to form a pattern of the insulating layer produced from the cured product of the present invention.

[0185] Another embodiment of the display device of the present invention is a display device comprising a thin film transistor (TFT) formed on a substrate and a planarizing film that covers irregularities on the substrate on which the TFT is formed, wherein the planarizing film is the cured product of the present invention.

[0186] Specifically, the display device preferably has a driving circuit, a planarization layer, a first electrode, an insulating layer, a light-emitting layer, and a second electrode on a substrate, with either or both of the planarization layer and the insulating layer being the cured product of the present invention. Taking an active matrix display device as an example, a substrate such as glass or a resin film has a TFT and wiring located on the sides of the TFT and connected to the TFT, a planarization layer on top of the TFT to cover the irregularities, and a display element is further provided on the planarization layer. The display element and the wiring are connected via contact holes formed in the planarization layer. The cured product obtained by curing the photosensitive resin composition of the present invention has excellent planarization properties and pattern dimensional stability, so it is preferably provided as a planarization layer in a display device. In particular, flexible display devices have become mainstream in recent years, and the display device may have a substrate having the driving circuit described above made of a resin film.

[0187] The present invention will be explained in more detail below by way of examples, but the present invention should not be construed as being limited to these specific examples. In addition, the names of the compounds used, for which abbreviations are used, are shown below.

[0188] (Diamine compound) BAP: 2,2-bis(3-amino-3-hydroxyphenyl)propane (Photoacid generator) PAG-103: "Irgacure" (registered trademark) PAG-103 (benzeneacetonitrile, 2-methyl-α-[[(propylsulfonyl)oxy]imino]-3(2H)-thienylidene, manufactured by BASF Japan Ltd.) NQD-1: naphthoquinone diazide sulfonic acid ester of 4,4'-(1-(4-(2-(4-hydroxyphenyl)propan-2-yl)phenyl)ethane-1,1-diyl)diphenol.

[0189] (Others) Lutidine: 2,6-lutidine CP: cyclopentanone GBL: γ-butyrolactone MPA: 3-methoxy-N,N-dimethylpropanamide NMP: N-methyl-2-pyrrolidone MX-270: NIKALAC (registered trademark) MX-270 (manufactured by Sanwa Chemical Co., Ltd.: thermal crosslinking agent having four bonded methoxymethyl groups) HMOM: HMOM-TPPHBA (manufactured by Honshu Chemical Industry Co., Ltd.: thermal crosslinking agent having six bonded methoxymethyl groups) (1) Weight-average molecular weight of polybenzoxazole precursor The weight-average molecular weight was measured using a gel permeation chromatography (GPC) analyzer under the following conditions. Measurement apparatus: Waters 2695 (manufactured by Waters) Column temperature: 50°C Flow rate: 0.4 mL / min Detector: 2489 UV / Vis Detector (measurement wavelength 260 nm) Developing solvent: NMP (containing 0.21 mass% lithium chloride and 0.48 mass% phosphoric acid) Guard column: TOSOH TSK guard column (manufactured by Tosoh Corporation) Column: TOSOH TSK-GEL a-2500, TOSOH TSK-GEL a-4000 in series (both manufactured by Tosoh Corporation).

[0190] (2) Content of fluorine atoms in the total resin in the photosensitive resin composition The resin was separated from the photosensitive resin composition and precisely weighed as a sample. Using the automatic sample combustion apparatus described below, the resin was combusted in a combustion tube of an analyzer. The generated gas was absorbed in the following absorption liquid, and a portion of the absorption liquid after absorption was analyzed by ion chromatography. The resin mass was taken as 100% by mass, and the mass of fluorine atoms relative to this was calculated as a percentage (mass%).

[0191] <Combustion and absorption conditions> System: AQF-2100H, GA-210 (manufactured by Mitsubishi Chemical Corporation) Electric furnace temperature: Inlet 900°C Outlet 1000°C Gas: Ar / O ２ 200mL / min :O ２ / 400 mL / min Absorption liquid: H ２ O ２0.036 mass%, internal standard P 4 μg / mL Amount of absorption solution: 20 mL <Conditions for ion chromatography and anion analysis> System: ICS1600 (manufactured by DINONEX Co., Ltd.) Mobile phase: 2.7 mmol / L Na ２ CO ３ / 0.3 mmol / L NaHCO ３ Flow rate: 1.5 mL / min. Detector: electrical conductivity detector. Injection volume: 20 μL.

[0192] (3) Protection Rate, Capping Rate of Main Chain End The protection rate was measured using a 400 MHz, 1H-NMR (nuclear magnetic resonance) spectrometer (AL-400 manufactured by JEOL Ltd.). Specifically, the measurement was performed 16 times in a deuterated dimethyl sulfoxide solution. The protection rate was calculated using the following formula, where M is the integral value of the protons of the phenolic hydroxyl groups observed in the vicinity of 9 ppm to 11 ppm in the resin before protection, and N is the integral value of the protons of the phenolic hydroxyl groups observed in the vicinity of 9 ppm to 11 ppm in the resin after protection.

[0193] Protection rate (%) = (MN) / M x 100.

[0194] The capping rate of the resin's main chain ends was measured using the same apparatus, heavy solvent, and cumulative number of measurements as used to calculate the protection rate. When the theoretical integral of protons derived from the ends in the case where 100% of the main chain ends are reacted with the end-capping agent is defined as P and the integral of the actually observed protons is defined as Q, the capping rate of the main chain ends can be calculated using the following formula:

[0195] Capping rate (%) of main chain ends = Q / P x 100.

[0196] (4) Solid Content Concentration The solid content concentration of the photosensitive resin composition was determined by the following method. 1.5 g of the solution was weighed into an aluminum cup and heated at 180°C for 30 minutes using a hot plate to evaporate the liquid. The mass of the solid content remaining in the aluminum cup after heating was weighed, and the solid content concentration was determined from the ratio to the mass before heating.

[0197] (5) Content of Compound Represented by Formula (10) The photosensitive resin composition sample was subjected to GC-MS analysis using a GC-MS device (manufactured by Agilent) under the following conditions: column temperature: 40 to 300°C, carrier gas: helium (1.5 mL / min), scan range: m / z 29 to 600. Each target compound was subjected to GC-MS analysis under the same conditions as above to create a calibration curve, and the content of the compound in the sample was calculated.

[0198] (6) Preparation of Relief Pattern A sample photosensitive resin composition was applied onto an 8-inch silicon wafer by spin coating using a coater / developer ACT-8 (manufactured by Tokyo Electron Limited), and heated at 100°C for 2 minutes to prepare a film of the photosensitive resin composition with a film thickness of 4.0 μm. The film thickness was measured using an optical interference film thickness measuring device Lambda Ace STM-602 (manufactured by SCREEN Holdings Co., Ltd.) under the condition of a refractive index of 1.629. Thereafter, using an i-line stepper NSR-2005i9C (manufactured by Nikon Corporation), the film was exposed to light at an exposure dose of 5 to 300 mJ / cm through a mask having a pattern of 10 μm contact holes. ２ in the range of 5 mJ / cm ２ After the exposure, the film was left to stand for 10 minutes in an environment of 23°C and 45% RH, and then developed for 10 to 80 seconds using the ACT-8 developing device with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH, manufactured by Tama Chemicals Co., Ltd.) as a developer, followed by rinsing with distilled water and shaking off to dry, thereby obtaining a relief pattern.

[0199] (7) Sensitivity Evaluation The relief pattern was observed at a magnification of 20 times using an FDP microscope MX61 (manufactured by Olympus Corporation), and the opening diameter of the contact hole was measured. The minimum exposure dose at which the opening diameter of the contact hole reached 10 μm was determined as Eth(1), and this was taken as the sensitivity. The results were evaluated as follows, and a sensitivity of 500 mJ / cm was determined. ２ Less than A ＋ -D was considered to be passing. ＋ is the most excellent.

[0200] A ＋ : Sensitivity is 80 mJ / cm ２A: Sensitivity is less than 80 mJ / cm ２ More than 100mJ / cm ２ Less than A － : Sensitivity is 100 mJ / cm ２ 130mJ / cm or more ２ B: Sensitivity is less than 130 mJ / cm ２ More than 170mJ / cm ２ Less than B － : Sensitivity is 170 mJ / cm ２ More than 200mJ / cm ２ Less than C ＋＋ : Sensitivity is 200 mJ / cm ２ More than 250mJ / cm ２ Less than C ＋ : Sensitivity is 250 mJ / cm ２ More than 300mJ / cm ２ C: Sensitivity is less than 300 mJ / cm ２ More than 400mJ / cm ２ Less than C － : Sensitivity is 400 mJ / cm ２ More than 500mJ / cm ２ Less than D ＋ : Sensitivity is 500 mJ / cm ２ More than 600mJ / cm ２ D: Sensitivity is less than 600 mJ / cm ２ More than 700mJ / cm ２ E: Sensitivity is less than 700 mJ / cm ２ More than 1000mJ / cm ２ F: Sensitivity is less than 1000 mJ / cm ２ That's all.

[0201] (8) Solubility in Thinner The evaluation of solubility in thinner was carried out as follows. A solvent prepared by mixing propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether in a mass ratio of 7:3 was used as the thinner. The sample photosensitive resin composition was applied to an 8-inch silicon wafer by spin coating using an ACT-8 coater / developer (manufactured by Tokyo Electron Limited), and heated at 100°C for 2 minutes to produce a 4.0 μm-thick film of the photosensitive resin composition. The film thickness was measured using an optical interference film thickness measuring device Lambda Ace STM-602 (manufactured by SCREEN Holdings Co., Ltd.) under a refractive index of 1.629. The wafer was then immersed in the thinner for 60 seconds. The presence or absence of residue remaining on the silicon wafer was observed.

[0202] The evaluation was made as follows, and grades A to C, which show that the area of ​​residues present on the entire wafer is less than 5%, were deemed to be acceptable. Grade A is the best.

[0203] A: The area where residues exist is less than 1%. B: The area where residues exist is 1% or more but less than 3%. C: The area where residues exist is 3% or more but less than 5%. D: The area where residues exist is 5% or more but less than 10%. E: The area where residues exist is 10% or more.

[0204] (9) Reflowability during curing Reflowability during curing, i.e., the degree of pattern change during the curing process, was determined by determining the change in contact hole diameter before and after thermal baking at 250°C for 1 hour in a nitrogen atmosphere. Specifically, a hole pattern with a diameter of 5 μm was formed, and the rate at which this hole pattern contracted during thermal baking (during the curing reaction) was observed. An inert oven INH-9CD (manufactured by Koyo Thermo Systems Co., Ltd.) was used for the thermal baking.

[0205] The shrinkage rate at the time of thermal firing is judged as follows, and A to C are those that are less than 30%. － A was deemed to be a pass. A was deemed to be the best.

[0206] A: Shrinkage rate less than 5% (diameter of contact hole after thermal baking is greater than 4.75 μm) B: Shrinkage rate 5% or more and less than 10% (diameter of contact hole after thermal baking is 4.5 μm or more and less than 4.75 μm) C ＋C: Shrinkage rate is 10% or more and less than 15% (diameter of contact hole after thermal baking is 4.25 μm or more and less than 4.5 μm) C: Shrinkage rate is 15% or more and less than 20% (diameter of contact hole after thermal baking is 4.0 μm or more and less than 4.25 μm) － D: Shrinkage rate is 20% or more and less than 25% (diameter of contact hole after thermal baking is 3.75 μm or more and less than 4.0 μm) ＋ A: Shrinkage rate of 25% or more and less than 30% (diameter of contact hole after thermal firing is 3.5 μm or more and less than 3.75 μm) D: Shrinkage rate of 30% or more and less than 50% (diameter of contact hole after thermal firing is 2.5 μm or more and less than 3.5 μm) E: Shrinkage rate of 50% or more (diameter of contact hole after thermal firing is less than 2.5 μm).

[0207] (10) Effect of Post-Exposure Standing Time A relief pattern was prepared in the same manner as in (6) above, except that the pattern was left for 24 hours in an environment of 23°C and 45% RH after exposure. The contact hole opening diameter of the resulting relief pattern was measured in the same manner as in (7) above, and the minimum exposure dose at which the contact hole opening diameter reached 10 μm was determined as Eth(2). Using the Eth(1) determined in (7) above, the sensitivity change y(%) was calculated using the following formula, and the evaluation was carried out according to the following criteria, with A to C being considered acceptable. A being the most excellent. Sensitivity change y(%)=Eth(2) / Eth(1)×100 A: Sensitivity change y is less than 110 B ＋ A: Sensitivity change y is 110 or more and less than 150 B: Sensitivity change y is 150 or more and less than 200 C: Sensitivity change y is 200 or more and less than 250 D: Sensitivity change y is 250 or more.

[0208] (11) Taper Angle A relief pattern was prepared in the same manner as in (6) above, using a 20 μm contact hole pattern instead of the 10 μm contact hole pattern. The minimum exposure dose Eth(1)' at which the contact hole opening diameter reached 20 μm was determined in the same manner as in (7) above. The relief pattern obtained with this minimum exposure dose was heat-treated in a clean oven CLH-21CD-S (Koyo Thermo Systems Co., Ltd.) at 250°C for 30 minutes under a nitrogen stream (oxygen concentration 20 ppm or less). A vertical cross section containing the maximum opening diameter of the contact hole pattern was then cut out, and the cross section was observed with a field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation) to measure the taper angle (see reference numeral 3 in Figure 1). The results were rounded to one decimal place and evaluated according to the following criteria, with A to D being considered acceptable. A was the most excellent. A: 35° or more B: 30° or more but less than 35° C: 25° or more but less than 30° D: 20° or more but less than 25° E: Less than 20°.

[0209] Synthesis Example 1 Synthesis of Polybenzoxazole Precursor (PBO-01) Under a dry nitrogen stream, 25.83 g (100 mmol) of BAP was dissolved in 106 g of MPA in a three-neck flask. The solution was then cooled to -15°C. After confirming that the solution temperature had reached -15°C, 12.68 g (75 mmol) of glutaryl chloride (glutaric acid dichloride) was added along with 30 g of MPA. After stirring at -10°C for 30 minutes, the solution was warmed to 20°C and stirred for an additional 2 hours. The solution was again cooled to -15°C. After confirming that the solution temperature had reached -15°C, 5.23 g (50 mmol) of methacryloyl chloride was added along with 10 g of MPA. After the dropwise addition was completed, stirring was continued for 2 hours at 20°C. After the reaction was completed, the above solution was poured into 2 liters of pure water to precipitate a white precipitate. The precipitate was collected by filtration, washed three times with pure water, and then dried in a vacuum dryer at 50°C for 72 hours to obtain a polybenzoxazole precursor (PBO-01). The weight-average molecular weight Mw of the obtained resin was 11,300, and the fluorine atom content was 0%. The blocking rate of the main chain ends was 95%. The evaluation results are shown in Table 1.

[0210] Synthesis Examples 2 to 31 Synthesis of Polybenzoxazole Precursors (PBO-02 to PBO-31) Synthesis was performed in the same manner as in Synthesis Example 1, except that the diacid dichloride, diamine, acid chloride, and solvent were changed to the types and amounts shown in Table 1. The results are shown in Table 1. In Table 1, the "mass %" in parentheses in the polymerization solvent column indicates the proportion when the total amount of solvent is taken as 100 mass %.

[0211]

[0212]

[0213]

[0214] Synthesis Example 32 Synthesis of Polybenzoxazole Precursor (PBO-01-BOC50) In a dry nitrogen stream, 8.00 g of PBO-01 was dissolved in 50 g of MPA in a three-neck flask as a base polymer. Then, 4.60 g (22 mmol) of di-tert-butyl dicarbonate and 0.13 g (1.1 mmol) of 4-dimethylaminopyridine were added, and the mixture was allowed to react at 20°C for 1 hour. After completion of the reaction, the solution was poured into 500 mL of pure water to precipitate a white precipitate. This precipitate was collected by filtration, washed three times with pure water, and then dried in a vacuum dryer at 50°C for 72 hours to obtain a polybenzoxazole precursor (PBO-01-BOC50). The results are shown in Table 2.

[0215] Synthesis Examples 33 to 38, 50 to 71, 89 to 90 Synthesis of polybenzoxazole precursors (PBO-02-BOC50 to PBO-31-BOC50) Synthesis was performed in the same manner as in Synthesis Example 32, except that the amounts of the base polymer, the protecting agent, the catalyst, and the solvent used were changed to those shown in Table 2. The results are shown in Table 2.

[0216]

[0217]

[0218]

[0219]

[0220] Synthesis Example 39 Synthesis of Polybenzoxazole Precursor (PBO-01-ACT50) 10 g of PBO-01 synthesized in Synthesis Example 1 as the base polymer and 30 g of CP as the solvent were weighed and dissolved in a three-necked flask under a dry nitrogen stream. 3.8 g of isopropyl vinyl ether was added as a protecting agent, and the mixture was stirred at 0°C for 1 hour. Next, 0.31 g of trifluoroacetic acid was added as a catalyst, and the mixture was stirred at 0°C for 3 hours. After stirring was completed, the acid catalyst was neutralized with a saturated aqueous sodium bicarbonate solution, and the water bath was removed. The organic layer was further washed twice with water. Thereafter, low-boiling point residues were removed using a rotary evaporator in order to remove unreacted isopropyl vinyl ether. Thereafter, the solids concentration of the solution was measured, and CP was added so that the solids content was 40%, yielding a 40% by mass solids solution of polybenzoxazole precursor (PBO-01-ACT50) in which the hydroxyl groups were protected with 1-isopropoxyethyl groups, which are acid-decomposable groups. The proportion of phenolic hydroxyl groups protected with acid-decomposable groups was 46 mol %. The results are shown in Table 2.

[0221] Synthesis Examples 40 to 45, 72 to 88, 91 to 92 Synthesis of polybenzoxazole precursors (PBO-02-ACT50 to PBO-31-ACT50) Synthesis was performed in the same manner as in Synthesis Example 39, except that the amounts of the base polymer, protecting agent, catalyst, and solvent used were changed to those shown in Table 2. The results are shown in Table 2.

[0222] Synthesis Example 46: Synthesis of Polybenzoxazole Precursor (PBO-08-AC50) Under a dry nitrogen stream, 8.00 g of PBO-08 as a base polymer was dissolved in 50 g of MPA in a three-neck flask. Then, 2.20 g (22 mmol) of acetic anhydride and 0.13 g (1.1 mmol) of 4-dimethylaminopyridine were added, and the mixture was allowed to react at 20°C for 6 hours. After completion of the reaction, the solution was poured into 500 mL of pure water to precipitate a white precipitate. This precipitate was collected by filtration, washed three times with pure water, and then dried in a vacuum dryer at 50°C for 72 hours to obtain polybenzoxazole precursor (PBO-08-AC50). The results are shown in Table 2.

[0223] Synthesis Examples 47 to 49 Synthesis of polybenzoxazole precursors (PBO-11-AC50, PBO-01-AC50, PBO-21-AC50) Synthesis was performed in the same manner as in Synthesis Example 46, except that the amounts of the base polymer, protecting agent, catalyst, and solvent used were changed to those shown in Table 2. The results are shown in Table 2.

[0224] Synthesis Example 93 Synthesis of quinone diazide compound NQD-1 Under a dry nitrogen stream, 21.22 g (0.05 mol) of TrisP-PA (manufactured by Honshu Chemical Industry Co., Ltd.) and 36.27 g (0.135 mol) of 5-naphthoquinone diazide sulfonyl chloride were dissolved in 450 g of 1,4-dioxane and the solution was allowed to cool to room temperature. To this solution, a solution of 15.18 g of triethylamine dissolved in 50 g of 1,4-dioxane was added dropwise so that the temperature in the system was 35°C or less. After the dropwise addition, the mixture was stirred at 30°C for 2 hours. The triethylamine salt was filtered, and the filtrate was poured into water. Filtration was then performed, and the precipitate was collected. This precipitate was dried in a vacuum dryer to obtain quinone diazide compound NQD-1 represented by formula (8).

[0225]

[0226] In formula (8), * represents the point of attachment to the oxygen atom. The esterification rate was 90 mol%.

[0227] Example 1 Under yellow light, 1.0 g of PBO-01-BOC50 as component (a), 0.40 g of the quinone diazide compound NQD-1 synthesized in Synthesis Example 93 as a photoacid generator (b), and 4.0 g of GBL as a solvent were added and stirred to prepare a positive photosensitive resin composition.

[0228] The positive photosensitive resin compositions thus prepared were evaluated for (7) sensitivity, (8) solubility in thinner, (9) reflowability upon curing, (10) effect of post-exposure standing time, and (11) taper angle. The results are shown in Table 3.

[0229] Examples 2 to 6, Examples 13 to 38, Examples 52 to 55, Examples 60 to 61, Comparative Examples 1, Comparative Examples 3 to 7, Comparative Examples 11 and 12 Resin compositions were prepared and evaluated in the same manner as in Example 1, except that the formulation of each component of the photosensitive resin composition was changed as shown in Table 3. The results are shown in Table 3.

[0230] Example 7 Under yellow light, (a) 2.50 g of a 40% solids CP solution of PBO-01-ACT50 as a resin, and (b) 0.15 g of PAG-103 and 0.005 g of lutidine as photoacid generators were added and stirred. Then, 1.50 g of CP was added to adjust the concentration, and a positive photosensitive resin composition was prepared.

[0231] The positive photosensitive resin compositions thus prepared were evaluated for (7) sensitivity, (8) solubility in thinner, (9) reflowability upon curing, (10) effect of post-exposure standing time, and (11) taper angle. The results are shown in Table 3.

[0232] Examples 8 to 12, Examples 39 to 51, Examples 56 to 59, Examples 62 to 63, Comparative Example 2, Comparative Examples 8 to 10, Comparative Examples 13 to 14 Resin compositions were prepared and evaluated in the same manner as in Example 7, except that the formulation of each component of the photosensitive resin composition was changed as shown in Table 3. The evaluation results are shown in Table 3.

[0233]

[0234]

[0235]

[0236]

[0237]

[0238] 1 Silicon wafer 2 Relief pattern 3 Taper angle of relief pattern

Claims

1. A photosensitive resin composition comprising a polybenzoxazole precursor having a repeating unit represented by formula (1) (hereinafter referred to as "component (a)") and a photoacid generator. (R １ and R ２ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. X represents a divalent linking group. V represents a linear or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms or a divalent aliphatic hydrocarbon group represented by formula (9). (n is an integer from 0 to 11, and m is an integer from 1 to 12, provided that n+m is 1 to 12. R ２０ and R ２１ is a hydrocarbon group having 2 to 4 carbon atoms when n=0, and is a hydrocarbon group having 1 to 4 carbon atoms when n≠0. * represents the point of attachment to the amide group.) 2. The photosensitive resin composition according to claim 1, wherein in the repeating unit represented by formula (1), V is a straight-chain or branched divalent aliphatic hydrocarbon group having 1 to 3 carbon atoms.

3. In the repeating unit represented by the formula (1), R １ and R ２ 3. The photosensitive resin composition according to claim 1, wherein either or both of the above are independently an alkyl group having 1 to 6 carbon atoms or a monovalent acid-decomposable group having 1 to 120 carbon atoms when both are present.

4. The photosensitive resin composition according to claim 1 or 2, wherein the component (a) contains a repeating unit represented by the formula (1) and a repeating unit represented by the following formula (2): (R ３ and R ４ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a monovalent acid-decomposable group having 1 to 120 carbon atoms. Y represents a divalent linking group. U represents a divalent aliphatic hydrocarbon group having 3 to 30 carbon atoms containing an alicyclic skeleton, or a straight-chain or branched divalent aliphatic hydrocarbon group having 4 to 20 carbon atoms (excluding groups corresponding to the divalent aliphatic hydrocarbon group represented by the above formula (9)).

5. The photosensitive resin composition according to claim 4, wherein component (a) contains 1 mol % or more of the repeating unit represented by formula (2) when the sum of the repeating unit represented by formula (1) and the repeating unit represented by formula (2) is taken as 100 mol %.

6. The photosensitive resin composition according to claim 1 or 2, wherein V in formula (1) is a divalent group represented by formula (3). (R ５ and R ６ each independently represents a hydrogen atom or a methyl group. * represents the point of attachment to the amide group.

7. The photosensitive resin composition according to claim 4, wherein U in formula (2) is a divalent aliphatic hydrocarbon group having 3 to 10 carbon atoms and containing an alicyclic structure.

8. The photosensitive resin composition according to claim 7, wherein the divalent aliphatic hydrocarbon group containing an alicyclic structure and having 3 to 10 carbon atoms has 3 to 5 carbon atoms.

9. R ３ and R ４ or both of are independently selected from the group consisting of alkyl groups having 1 to 6 carbon atoms and monovalent acid-decomposable groups having 1 to 120 carbon atoms, when both are present.

10. The photosensitive resin composition according to claim 1 or 2, further comprising a thermal crosslinking agent.

11. The photosensitive resin composition according to claim 10, wherein all or a part of the thermal crosslinking agent has five or more thermal crosslinkable groups.

12. The photosensitive resin composition according to claim 1 or 2, which does not contain a compound represented by the following formula (10), or if it does contain one, the amount of the compound is 0.3 mass% or less when the total amount of the photosensitive resin composition is 100 mass%. (R ２２ represents a hydrogen atom or a monovalent organic group having 1 to 6 carbon atoms; R ２３ When a plurality of groups are present, each independently represents a monovalent organic group having 1 to 12 carbon atoms, s is 2 or 3, and t is an integer satisfying 0≦t≦(s+1).

13. A photosensitive resin composition according to claim 1 or 2, in which the content of fluorine atoms in the resin is less than 5 mass%, when the total mass of the resin contained in the photosensitive resin composition is 100 mass%.

14. A photosensitive resin sheet comprising the photosensitive resin composition according to claim 1 or 2 formed in the form of a film on a support.

15. A cured product obtained by curing the photosensitive resin composition according to claim 1 or 2.

16. A method for producing a cured film on a substrate, comprising the steps of: preparing a substrate; forming a film of the photosensitive resin composition according to claim 1 or 2 on the substrate; exposing the film of the photosensitive resin composition to light to form a latent image in the film; developing the exposed film of the photosensitive resin composition with an aqueous alkaline solution; and curing the developed film of the photosensitive resin composition.

17. A semiconductor device comprising the cured product according to claim 15.

18. A display device comprising a first electrode formed on a substrate, an insulating layer formed so as to partition pixels provided on the first electrode, and a second electrode provided opposite the first electrode, wherein the insulating layer is made of the cured product according to claim 15.

19. A display device comprising a thin film transistor (TFT) formed on a substrate, and a planarizing film that covers irregularities on the substrate on which the TFT is formed, the planarizing film being the cured product according to claim 15.

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