TWI859737B - Photosensitive resin composition, polyimide cured film, and method for producing the same - Google Patents

Abstract

The present invention provides a cured film which exhibits high substrate adhesion, has a low dielectric loss factor, can inhibit corrosion of a copper substrate and has a high tensile elongation. The present invention provides a photosensitive resin composition comprising (A) a polyimide precursor represented by the following general formula (1), (B) a photosensitizer, and (C) a solvent. In the general formula (1), at least one of _R1 and _R2 is an organic group having a polymerizable group and a nitrogen atom, and the molecular orbital energy _Hsd (eV) of the highest occupied molecular orbital (HOMO) of the structure of _R1 or _R2 satisfies -9.9≦ _Hsd ≦-8.5, or the polyimide precursor includes both structures represented by the following general formula (2) and the following general formula (3).

Description

Photosensitive resin composition, polyimide cured film, and method for producing the same

The present invention relates to a photosensitive resin composition, a polyimide hardened film, and a method for manufacturing the same.

Previously, insulating materials for electronic parts, passivation films for semiconductor devices, surface protection films, interlayer insulating films, etc. used polyimide resins with excellent heat resistance, electrical properties, and mechanical properties. Among the polyimide resins, a photosensitive polyimide precursor composition is provided that can easily form a heat-resistant hardened relief pattern film by coating, exposure, development, and curing-based thermal imidization treatment of the composition. This photosensitive polyimide precursor composition has the characteristic of greatly shortening the steps compared to the previous non-photosensitive polyimide material.

Semiconductor devices (hereinafter also referred to as "components") are mounted on printed circuit boards by various methods depending on their purpose. Previously, components were usually manufactured by wire bonding, which connects the external terminals (pads) of the components to the lead frame with finer wires. However, recently, a semiconductor chip packaging technology called fan-out wafer-level packaging (FOWLP) has been proposed from the perspectives of high-speed transmission or thinner package height. The so-called FOWLP is a packaging technology that manufactures single chips by slicing the wafer that has completed the previous step, reassembling the single chips on a support and sealing them with a mold resin, and then peeling off the support to form a redistribution layer.

In recent years, the development of packages for the fifth generation mobile communication system (5G), which is a new communication standard, has become a top priority. 5G is different from the previous technology 4G. By using the millimeter wave (10 GHz to 80 GHz) frequency band, it can achieve high speed and large capacity, low signal latency, and simultaneous connection of multiple terminals that did not exist in previous communications. Regarding the millimeter wave band, the impact of transmission loss in the signal wiring of the printed wiring board is relatively large, and there are concerns about heat generation or transmission delay. Therefore, in order to reduce transmission loss, an antenna package (AiP) has been developed that integrates the front-end module (FEM) for transmitting and receiving radio waves with the antenna (for example, refer to the following patent document 1). AiP can suppress the transmission loss that increases in proportion to the wiring length because the wiring length is shorter. [Prior art literature]  [Patent literature]

[Patent Document 1] U.S. Patent Application Publication No. 2016/0104940

[The problem the invention is trying to solve]

On the other hand, the suppression of transmission loss in package design is also limited, and improvements in materials are also expected. When the dielectric properties of the insulating material used to form the wiring, such as dielectric constant and dielectric dissipation factor (tanδ), are high, the dielectric loss increases, and as a total, the transmission loss increases. Although polyimide has excellent insulating properties and film physical properties, its basic body is a polar functional group. Furthermore, the photosensitive polyimide precursor composition contains many polar compounds such as photopolymerization initiators and cross-linking agents. Therefore, the value of the dielectric properties is usually higher and is required to be lowered. In addition, the transmission loss increases due to the skin effect caused by the unevenness of the substrate, so a smoother substrate is desired. Therefore, the adhesion between the substrate and the resin is lower than that of the previous substrate, and a resin with excellent adhesion to a smooth substrate is required. Acidic compounds have shown good effects in improving adhesion to the substrate, but they will lead to Corrosion of the metal substrate.

Therefore, the purpose of the present invention is to provide a photosensitive resin composition, a method for producing the same, a polyimide cured film using the photosensitive resin composition, and a method for producing the same, wherein the photosensitive resin composition can provide a cured film that exhibits high substrate adhesion, has a low dielectric loss factor, can inhibit corrosion of the copper substrate, and has a high tensile elongation. [Technical means for solving the problem]

Examples of embodiments of the present invention are listed in the following items [1] to [12]. [1] A photosensitive resin composition comprising (A) a polyimide precursor, (B) a photosensitizer, and (C) a solvent, wherein the polyimide precursor (A) comprises a structure represented by the following general formula (1). {In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, _R1 and _R2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. At least one of _R1 and _R2 is an organic group having a polymerizable group and a nitrogen atom, and the molecular orbital energy _Hsd (eV) of the highest occupied molecular orbital (HOMO) of the structure of _R1 or _R2 having a polymerizable group and a nitrogen atom satisfies -9.9≦ _Hsd ≦-8.5}. [2] A photosensitive resin composition comprising (A) a polyimide precursor, (B) a photosensitizer, and (C) a solvent, wherein the polyimide precursor (A) comprises a structure represented by the following general formula (1). [Chemistry 2] {In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, _R1 and _R2 are independently selected from the group consisting of a hydrogen atom, an organic group represented by the following general formula (2), and an organic group represented by the following general formula (3), wherein the above-mentioned (A) polyimide precursor comprises both structures represented by the following general formula (2) and the following general formula (3)}. [Chemistry 3] {In general formula (2), R ₃ , R ₄ and R ₅ are independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and R ₆ is a divalent organic group having 1 to 10 carbon atoms or a divalent organic group containing a ring structure}. [Chemistry 4] {In general formula (3), _R7 , _R8 , and _R9 are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, _R10 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, _R11 is an _m1 +1-valent organic group having 2 to 10 carbon atoms or an _m1 + ₁ -valent organic group containing a ring structure, _R12 is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and _m1 is an integer of 1 to 4}. [3] A photosensitive resin composition as described in item 1, wherein in general formula (1), at least one of _R1 and _R2 is an organic group represented by the following general formula (3). [Chemistry 5] {In the general formula (3), _R7 , _R8 , and _R9 are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, _R10 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, _R11 is an _m1 + ₁ -valent organic group having 2 to 10 carbon atoms or an _m1 +1-valent organic group containing a ring structure, _R12 is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and _m1 is an integer from 1 to 4}. [4] The photosensitive resin composition as described in item 2 or 3, wherein the content of the organic group of the general formula (3) in the polyimide precursor is 5 mol% to 90 mol% relative to the total molar amount of _R1 and _R2 in the general formula (1). [5] A photosensitive resin composition as described in any one of items 2 to 4, wherein in the above general formula (3), R ₁₀ is a monovalent organic group having 1 to 10 carbon atoms. [6] A photosensitive resin composition as described in any one of items 2 to 5, wherein in the general formula (3), R ₁₀ is a monovalent organic group having 1 to 5 carbon atoms. [7] A photosensitive resin composition as described in any one of items 2 to 6, wherein the general formula (3) is represented by the following structure. [Chemistry 6] {In general formula (4), _R21 , _R22 , _{and R23} are independently _a hydrogen atom or _a monovalent organic group having 1 to 5 carbon atoms, _R24 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, _{and R25} is a divalent organic group having 2 to 10 carbon atoms}. [8] A photosensitive resin composition as claimed in any one of claims 1 to 7, wherein in the general formula (1), _Y1 comprises a structure represented _by the following general formula (Y1): [Chemical 3] {wherein, Rz is independently a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a is independently an integer of 0 to 4, A is independently an oxygen atom or a sulfur atom, and B is a single bond or the following formula: [Chemical 4] [9] A polyimide cured film having a closed ring rate of 10% to 95% and comprising at least one structure selected from the following general formula (1) or (5). [Chemistry 7] {In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, and _R1 and _R2 are groups represented by the following general formula (3)}. [Chemistry 8] {In general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1-valent organic group having 2 to 10 carbon atoms or an m ₁ +1-valent organic group containing a ring structure, R ₁₂ is a divalent organic group having ₁ to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer from 1 to 4}. [Chemistry 9] {In the general formula (5), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n2 is an integer of 2 to 150, and _R13 is a group represented by the following general formula (3)}. [Chemical 10] {In general formula (3), _R7 , _R8 , and _R9 are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, _R10 is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, _R11 is an _m1 +1-valent organic group having 2 to 10 carbon atoms or an _m1 + ₁ -valent organic group containing a ring structure, _R12 is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, _{and m1} is an integer of 1 to 4}. [10] The polyimide cured film as recited in item 9, wherein the polyimide cured film is an insulating film for redistribution. [11] A method for preparing a photosensitive resin composition, the method comprising the following steps: (A) a step of synthesizing a polyimide precursor; and a step of preparing the photosensitive resin composition in a manner comprising (A) the polyimide precursor, (B) a photosensitive agent, and (C) a solvent; the above-mentioned synthesis step comprises the following steps: a step of obtaining an acid/amide body by reacting tetracarboxylic dianhydride with an amide group-introducing compound; The step of reacting the acid/amide body with an alcohol to obtain an acid/amide/ester body; and the step of polycondensing the acid/amide/ester body with a diamine monomer to synthesize a (A) polyimide precursor having an amide structure and an ester structure; and the (A) polyimide precursor has three or more amide structures per repeating unit. [12] A method for producing a polyimide cured film, the method comprising the following steps (1) to (5): (1) coating a photosensitive resin composition containing a polyimide precursor on a substrate to form a photosensitive resin layer on the substrate; (2) heating and drying the obtained photosensitive resin layer; (3) exposing the heated and dried photosensitive resin layer to light; (4) developing the exposed photosensitive resin layer; and (5) heating the developed photosensitive resin layer to form a polyimide cured film. The polyimide precursor comprises a structure represented by the following general formula (1). {In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, _R1 and _R2 are independently selected from the group consisting of a hydrogen atom, an organic group represented by the following general formula (2), and an organic group represented by the following general formula (3), wherein the polyimide precursor comprises both the structures represented by the following general formula (2) and the following general formula (3)}. [Chemistry 12] {In general formula (2), R ₃ , R ₄ and R ₅ are independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and R ₆ is a divalent organic group having 1 to 10 carbon atoms or a divalent organic group containing a ring structure}. [Chemical 13] {In formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms _{, R 11 is} an m ₁ +1-valent organic group having 2 to 10 carbon atoms or an m ₁ +1-valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4}. [Effects of the Invention]

When the photosensitive resin composition of the present invention is used, a cured film can be provided which exhibits high substrate adhesion, has a low dielectric loss factor, can suppress corrosion of the copper substrate, and has a high tensile elongation.

The following is a detailed description of the implementation of the present invention. Furthermore, the present invention is not limited to the following implementation, and can be implemented in various ways within the scope of its purpose. Throughout this specification, when there are multiple structures represented by the same symbol in the general formula in a molecule, unless otherwise specified, they can be independently selected and can be the same or different. In addition, structures represented by common symbols in different general formulas can also be independently selected and can be the same or different as long as they are not otherwise specified.

"Photosensitive resin composition" The photosensitive resin composition of the present invention comprises (A) a polyimide precursor, (B) a photosensitive agent (photopolymerization initiator), and (C) a solvent, and optionally further comprises a free radical polymerizable monomer or other components. Each component is described below in sequence. Based on the physical properties of the following (A) polyimide precursor, the photosensitive resin composition is preferably negative.

[(A) Polyimide Precursor] (A) The polyimide precursor is a resin component contained in the photosensitive resin composition, and is a polyamide having a structural unit represented by the following general formula (1). [Chemical 14] {In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, and _R1 and _R2 are independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms}. In the present invention, _R1 and _R2 in the general formula (1) are also referred to as "side chains" or "side chain structures" of the polyimide precursor.

In the above general formula (1), at least one of _R1 and _R2 is preferably an organic group having a polymerizable group and a nitrogen atom. Moreover, among _R1 and _R2 , the organic group having a polymerizable group and a nitrogen atom preferably has a molecular orbital energy _Hsd (eV) of the highest occupied molecular orbital (HOMO) of its structure satisfying the following formula: -9.9≦ _Hsd ≦-8.5. The calculation of HOMO is performed by the method shown in the following examples, and the unit is eV. Although not limited in theory, by providing the (A) polyimide precursor with a side chain structure having a HOMO molecular orbital energy within the above range, the reactivity of the diamine to the tetracarboxylic dianhydride is increased, and the molecular weight reduction of the polyimide resin after heat curing can be suppressed, thereby maintaining or improving the tensile elongation.

From the viewpoint of improving substrate adhesion, the lower limit of the molecular orbital energy H _sd of the highest occupied molecular orbital (HOMO) is preferably not less than -9.9, and more preferably not less than -9.8. From the viewpoint of improving tensile elongation, the upper limit of H _sd that can be combined with the lower limit is more preferably not more than -8.5, and more preferably not more than -8.7.

From the viewpoint of low dielectric loss factor and improved substrate adhesion, the (A) polyimide precursor preferably has three or more amide structures per repeating unit. Preferably, among the three or more amide structures, two are amide bonds of the main chain, and the other amide structures are derived from nitrogen atoms present in at least one of _R1 and _R2 of the side chain. In the present invention, the side chain having an amide structure is also referred to as an "amide side chain". Although not limited in theory, it is believed that when the photosensitive resin layer obtained from the photosensitive resin composition is cured by heat, the polyimide precursor of the amide side chain has a high ring closing temperature and the side chain is not easily detached, so that the amount of polar molecules present in the cured film is reduced and the dielectric loss factor is lowered. In addition, it is believed that since the side chain has an amide structure with a high ring closing temperature, the amide structure is also included in the cured film after heat curing, thereby enhancing the interaction with the metal and improving the substrate adhesion.

In the general formula (1), _R1 and _R2 are preferably independently selected from the group consisting of a hydrogen atom, an organic group represented by the following general formula (2), and an organic group represented by the following general formula (3). {In general formula (2), R ₃ , R ₄ and R ₅ are independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and R ₆ is a divalent organic group having 1 to 10 carbon atoms or a divalent organic group containing a ring structure. The symbol "*" indicates a bond with general formula (1)}.

In the general formula (2), the monovalent organic group having 1 to 3 carbon atoms in R ₃ , R ₄ and R ₅ is preferably a monovalent alkyl group having 1 to 3 carbon atoms. As the alkyl group, an alkyl group having 1 to 3 carbon atoms is more preferably used, and examples thereof include a methyl group, an ethyl group, and a butyl group. In the general formula (2), R ₃ is more preferably a hydrogen atom or a methyl group, and from the viewpoint of photosensitivity, R ₄ and R ₅ are more preferably a hydrogen atom. R ₆ is preferably a divalent organic group having 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 5 carbon atoms, such as a divalent alkyl group. R ₆ is more preferably an alkylene group having 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 5 carbon atoms, or an arylene group having 6 to 10 carbon atoms. As the alkylene group, examples thereof include a methylene group, an ethylene group, and a propylene group. As the aryl group, phenyl group and the like can be exemplified. _R6 is further preferably ethyl group. Furthermore, in the present invention, the alkyl group may be saturated or unsaturated, may be straight chain or branched chain, may have a ring structure, and a part of the hydrogen atoms may be substituted by other organic groups or may not be substituted. The alkyl group may be straight chain or branched chain, and a part of the hydrogen atoms may be substituted by other organic groups or may not be substituted. The alkyl group may be straight chain or branched chain, and a part of the hydrogen atoms may be substituted by other organic groups or may not be substituted. Regarding the aryl group, a part of the hydrogen atoms may be substituted by other organic groups or may not be substituted. As other organic groups that may also replace a part of the hydrogen atoms of the alkyl group, alkyl group, alkyl group and aryl group, halogen atoms, hydroxyl group, amino group, and carboxyl group can be exemplified.

[Chemistry 16] {In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1-valent organic group having 2 to 10 carbon atoms or an m ₁ +1-valent organic group containing a ring structure, R ₁₂ is a divalent organic group having ₁ to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4. The symbol "*" indicates a bond with the general formula (1)}.

In the general formula (3), the monovalent organic group having 1 to 5 carbon atoms in _R7 , _R8 and _R9 is preferably a alkyl group, more preferably an alkyl group, for example, a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. _R7 is more preferably a hydrogen atom or a methyl group, and from the viewpoint of photosensitivity, _R8 and _R9 are more preferably a hydrogen atom. The organic group _{in R10} is preferably a monovalent organic group having 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 5 carbon atoms, for example, a monovalent alkyl group. _R10 is more preferably a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 5 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. R _{1 1} is preferably a divalent organic group having 2 to 10 carbon atoms, 2 to 7 carbon atoms, 2 to 6 carbon atoms, or 2 to 5 carbon atoms, such as a divalent alkyl group. R _{1 1} is more preferably a hydrogen atom, or an alkylene group having 2 to 10 carbon atoms, 2 to 7 carbon atoms, 2 to 6 carbon atoms, or 2 to 5 carbon atoms, or an arylene group having 6 to 10 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, and a propylene group. Examples of the arylene group include a phenylene group. The heteroatom of R _{1 2} is preferably an oxygen atom. R _{1 2} is preferably a divalent organic group having an ester group (ester bond) and having 1 to 5 carbon atoms, or 1 to 3 carbon atoms. The organic group of R _{1 2} preferably includes an ester group and is a divalent hydrocarbon group having 1 to 5 carbon atoms or 1 to 3 carbon atoms. From the viewpoint of photosensitivity, m ₁ is preferably an integer of 1 to 3, such as 1 or 2.

At least one of _R1 and _R2 in the general formula (1) is preferably a structure represented by the general formula (3). In this way, the adhesion to the substrate can be improved without deteriorating the tensile elongation. Although not limited in theory, it is believed that when the photosensitive resin layer obtained from the photosensitive resin composition is heated and cured, the polyimide precursor of the amide side chain has a high ring closing temperature and the side chain is not easily separated, so that the amount of polar molecules present in the cured film is reduced and the dielectric loss factor is lowered. In addition, it is considered that since the side chain has an amide structure with a high ring closing temperature, the amide structure is also included in the cured film after heat curing, thereby enhancing the interaction with the metal and improving the adhesion.

The content of the organic group of the general formula (3) in the polyimide precursor is preferably 5 mol% to 90 mol% relative to the total molar amount of _R1 and _R2 in the general formula (1). If the content of the organic group of the general formula (3) is 5 mol% or more, there is a tendency for good adhesion. From the viewpoint of low dielectric loss tangent, the lower limit of the content of the organic group of the general formula (3) is more preferably 8 mol% or more. The upper limit of the content of the organic group of the general formula (3) in the polyimide precursor that can be combined with the lower limits is preferably 80 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, or 20 mol% or less from the viewpoint of tensile elongation. The total content of the organic groups of the general formula (2) and the general formula (3) in the polyimide precursor is preferably 85 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more relative to the total molar amount of _R1 and _R2 in the general formula (1). When the organic groups of the general formula (2) and the general formula (3) are 85 mol% or more, the corrosion of the copper substrate can be suppressed, and the storage stability of the varnish tends to be improved.

The (A) polyimide precursor preferably includes both the structures represented by the above general formula (2) and the above general formula (3). For example, it is preferred that either R ₁ or R ₂ is a structure represented by the general formula (2), and the other is a structure represented by the general formula (3). The structure represented by the general formula (2) and the structure represented by the general formula (3) may exist in a single repeating unit (1), or may exist in different repeating units (1). The (A) polyimide precursor having the structures represented by both the general formula (2) and the general formula (3) tends to have a good tensile elongation.

From the viewpoint of low dielectric loss factor and substrate adhesion, the general formula (3) is more preferably a group represented by the following general formula (4). {In general formula (4), R _{2 1} , R _{2 2} , and R _{2 3} are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R _{2 4} is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and R _{2 5} is a divalent organic group having 2 to 10 carbon atoms. The symbol "*" indicates a bond with general formula (1)}.

In the general formula (4), _R21 is preferably a hydrogen atom or a methyl group, and _R22 and _R23 are preferably hydrogen atoms from the viewpoint of photosensitivity. _R24 is preferably a monovalent organic group having 1 to 10 carbon atoms, 1 to 7 carbon atoms, or 1 to 5 carbon atoms, such as a monovalent alkyl group. _R25 is preferably a divalent organic group having 2 to 10 carbon atoms, 2 to 7 carbon atoms, or 2 to 5 carbon atoms, such as a divalent alkyl group.

As specific examples of the organic groups represented by the general formulae (3) and (4), for example, the group represented by the following chemical formula (9) can be cited: [Chemical 18] {The symbol "*" indicates a connection with the general formula (1)}, but is not limited thereto.

From the viewpoint of the photosensitivity and mechanical properties of the photosensitive resin composition, _n1 in the general formula (1) is preferably an integer of 3-100, more preferably an integer of 5-70.

In the above general formula (1), the tetravalent organic group represented by _X1 is preferably an organic group having 6 to 40 carbon atoms, and more preferably an aromatic group or an alicyclic aliphatic group in which _-COOR1 and _-COOR2 are adjacent to -CONH- in order to achieve both heat resistance and photosensitivity. As the tetravalent organic group represented by _X1 , specifically, an organic group having 6 to 40 carbon atoms and containing an aromatic ring can be cited, for example, a group having a structure represented by the following general formula (7): [Chemical 19] {In general formula (7), R ₁₁ is a monovalent _group selected from the group consisting of a hydrogen atom, a fluorine atom, a alkyl group having 1 to 10 carbon atoms, and a fluorine-containing alkyl group having 1 to 10 carbon atoms, m ₅ is an integer of 0 to 2, m ₆ is an integer of 0 to 3, and m ₇ is an integer of 0 to 4}, but is not limited thereto. Furthermore, the structure of X ₁ may be one type or a combination of two or more types. In terms of both heat resistance and photosensitivity, the X ₁ group having the structure represented by the above formula (7) is particularly preferred.

In the above general formula (1), in order to take both heat resistance and photosensitivity into consideration, the divalent organic group represented by _Y1 is preferably an aromatic group having 6 to 40 carbon atoms, for example, the structure represented by the following general formula (8): {In general formula (8), R ₁₁ is a monovalent _group selected from the group consisting of a hydrogen atom, a fluorine atom, a alkyl group having 1 to 10 carbon atoms, and a fluorine-containing alkyl group having 1 to 10 carbon atoms, m ₅ is an integer of 0 to 2, m ₆ is an integer of 0 to 3, and m ₇ is an integer of 0 to 4}, but is not limited thereto. In addition, the structure of Y ₁ may be one or a combination of two or more. In terms of both heat resistance and photosensitivity, a Y ₁ group having the structure represented by the above formula (8) is particularly preferred.

_Y1 is preferably a structure represented by the following general formula (Y1): [Chemical 3] {wherein, Rz each independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a each independently represents an integer of 0 to 4, and A each independently represents an oxygen atom or a sulfur atom. And B is a single bond or the following formula: [Chemical 4] 1 of , or a single key}.

The organic group of Rz may be, for example, a monovalent organic group, a alkyl group, or an alkyl group having 1 to 10 carbon atoms, 1 to 5 carbon atoms, or 1 to 3 carbon atoms. a is an integer of 0 to 4, preferably 0 to 2, more preferably 0 or 1, and may be 0.

[Synthesis method of (A) polyimide precursor]  The synthesis method of the (A) polyimide precursor comprising the structure represented by the above general formula (1) in the present invention can be exemplified by the following method (i): (i) A method comprising the following steps: a step of obtaining an acid/amide body by reacting tetracarboxylic dianhydride with an amide group-introducing compound; a step of obtaining an acid/amide/ester body by reacting the above acid/amide body with an alcohol; and a step of synthesizing a (A) polyimide precursor having an amide structure and an ester structure by polycondensing the above acid/amide/ester body with a diamine monomer.

Alternatively, it can also be synthesized by the following method (ii): (ii) a method comprising the following steps: a step of obtaining polyamide by subjecting tetracarboxylic dianhydride and diamine monomer to a condensation reaction; a step of obtaining polyamide having an amide structure by reacting the polyamide with an amide group-introducing compound; and a step of synthesizing (A) a polyimide precursor having an amide structure and an ester structure by reacting the polyamide having an amide structure with an alcohol.

Method (i) is described below. In method (i), first, tetracarboxylic dianhydride is mixed with an amide group-introducing compound, and the tetracarboxylic dianhydride is reacted with an amine to amidate at least one anhydride group of the acid dianhydride, thereby introducing an amide structure. In the present invention, the compound (monomer) obtained by introducing an amide structure into tetracarboxylic dianhydride is referred to as an "acid/amide body".

Examples of the tetracarboxylic dianhydride in the method (i) include tetracarboxylic dianhydride containing the aforementioned tetravalent organic group _X1 having 6 to 40 carbon atoms. Examples of the tetracarboxylic dianhydride containing a tetravalent organic group _X1 having 6 to 40 carbon atoms include pyromellitic anhydride, diphenyl ether-3,3',4,4'-tetracarboxylic anhydride, benzophenone-3,3',4,4'-tetracarboxylic anhydride, biphenyl-3,3',4,4'-tetracarboxylic anhydride, diphenylsulfone-3,3',4,4'-tetracarboxylic anhydride, diphenylmethane-3,3',4,4'-tetracarboxylic anhydride, 2,2-bis(3,4-phthalic anhydride)propane, 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane, and 4,4'-(4,4'-isopropylidene diphenoxy) acid anhydride. These may be used alone or in combination of two or more.

As the amide group-introducing compound in the method (i), preferably, an amine compound can be exemplified, more preferably, an amine compound having an amino group and a polymerizable group, and further preferably, an amine compound having a structure in which a hydrogen atom is bonded to the portion marked with the symbol "*" of the monovalent organic group represented by the general formula (3) above.

In the method (i), an alcohol is added to the above-mentioned acid/amide body to allow the esterification reaction to proceed, thereby introducing an ester structure into the acid/amide body. In the present invention, the compound (monomer) obtained by introducing an ester structure into the acid/amide body is referred to as an "acid/amide/ester body".

As the alcohol in the method (i), there can be exemplified (a) an alcohol having a structure in which a hydrogen atom is bonded to the portion of the symbol "*" of the monovalent organic group represented by the general formula (2) above, and (b) an alcohol having a structure other than the group represented by the general formula (2) above as required. The reaction conditions are preferably, for example, dissolving and mixing the raw material compound in a reaction solvent in the presence of an alkaline catalyst such as pyridine. The reaction temperature can be, for example, 20°C to 50°C. The reaction time is preferably 4 to 10 hours of stirring.

Examples of the alcohol (b) having a structure other than the group represented by the general formula (2) include aliphatic alcohols having 5 to 30 carbon atoms or aromatic alcohols having 6 to 30 carbon atoms, such as 1-pentanol, 2-pentanol, 3-pentanol, neopentyl alcohol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 1-nonanol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, benzyl alcohol, and the like.

The reaction solvent is preferably one that dissolves the acid/ester body and the polyimide precursor that is the condensation product of the acid/ester body and the diamine monomer. Examples of the reaction solvent include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, γ-butyrolactone, ketones, esters, lactones, ethers, halogenated hydrocarbons, hydrocarbons, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, chlorobenzene, o-dichlorobenzene, hexane, heptane, benzene, toluene, and xylene. These solvents may be used alone or in combination of two or more, as required.

In the method (i), the obtained acid/amide/ester is then subjected to a condensation reaction with a diamine monomer to synthesize a polyimide precursor (A) having an amide structure and an ester structure.

Examples of the diamine monomer in the method (i) include diamine monomers containing the above-mentioned divalent organic group _Y1 having 6 to 40 carbon atoms. The diamine monomer of ₁ may be, for example, p-phenylenediamine, m-phenylenediamine, 4,4-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-Diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]sulfone 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, di-ortho-toluidine, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis{3-methyl-4-(4-aminophenyl) The present invention also includes bis{4-(4-aminophenoxy)phenyl}propane, bis{4-(4-aminophenoxy)phenyl}ketone, and those in which a portion of the hydrogen atoms on the benzene ring is substituted with methyl, ethyl, hydroxymethyl, hydroxyethyl, halogen, etc., such as 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, and mixtures thereof. However, the diamine monomer is not limited to the above.

The reaction sequence of the polycondensation reaction in the method (i) is not limited. For example, a known dehydration condensation agent is mixed with the above acid/amide/ester body (typically, the solution in the above reaction solvent) under ice cooling to convert the acid/amide/ester body into a polyanhydride, and then a diamine monomer containing a divalent organic group _Y1 having 6 to 40 carbon atoms separately dissolved or dispersed in a solvent is added dropwise thereto to carry out polycondensation to obtain a polyimide precursor. Examples of the dehydrating condensing agent include dicyclohexylcarbodiimide, 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, 1,1-carbonyldioxy-di-1,2,3-benzotriazole, and N,N′-disuccinimidyl carbonate.

Next, method (ii) is described. In method (ii), before the amide structure and the ester structure are introduced, a polycondensation reaction of tetracarboxylic dianhydride and diamine monomer is first performed to obtain a polyamide solution. The tetracarboxylic dianhydride, diamine monomer, and reaction solvent in method (ii) are the same as those described above with respect to method (i).

In the method (ii), an amide group-introducing compound is reacted with the above-mentioned polyamide to obtain a polyamide having an amide structure. The amide group-introducing compound in the method (ii) is preferably an isocyanate compound, and more preferably an isocyanate compound having a structure in which a portion of "*-N(R _{1 0} )-R _{1 1 -} " of the monovalent organic group represented by the above-mentioned general formula (3) is substituted with "O=C=NR _{1 1} -".

In the method (ii), the alcohol is then reacted with the polyamide having an amide structure to synthesize the (A) polyimide precursor having an amide structure and an ester structure. The alcohol in the method (ii) is the same as that described above in relation to the method (i).

In the method (ii), the existence ratio of the polyamine on the side chain tends to increase compared with the method (i).

In the methods (i) and (ii), from the viewpoint of low dielectric dissipation factor and improved substrate adhesion, the polyimide precursor (A) preferably has three or more amide structures per repeating unit. It is preferred that among the three or more amide structures, two are amide bonds of the main chain, and the other amide structures are derived from nitrogen atoms present in at least one of _R1 and _R2 . Although not limited in theory, it is believed that when the photosensitive resin layer obtained from the photosensitive resin composition is cured by heat, the polyimide precursor of the amide side chain has a high ring closing temperature and the side chain is not easily detached, so that the amount of polar molecules present in the cured film is reduced and the dielectric loss factor is lowered. In addition, it is believed that since the side chain has an amide structure with a high ring closing temperature, the amide structure is also included in the cured film after heat curing, thereby enhancing the interaction with the metal and improving the substrate adhesion.

In the methods (i) and (ii), the content of the organic group of the general formula (3) in the polyimide precursor is preferably 5 mol% to 90 mol% relative to the total molar amount of _R1 and _R2 in the general formula (1). If the content of the organic group of the general formula (3) is 5 mol% or more, there is a tendency for good adhesion. From the perspective of low dielectric loss tangent, the lower limit of the content of the organic group of the general formula (3) is more preferably 8 mol% or more. From the perspective of tensile elongation, the upper limit of the content of the organic group of the general formula (3) in the polyimide precursor that can be combined with the lower limits is preferably 80 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, 30 mol% or less, or 20 mol% or less. The total content of the organic groups of the general formula (2) and the general formula (3) in the polyimide precursor is preferably 85 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more relative to the total molar amount of _R1 and _R2 in the general formula (1). When the organic groups of the general formula (2) and the general formula (3) are 85 mol% or more, the corrosion of the copper substrate can be suppressed, and the storage stability of the varnish tends to be improved.

In the methods (i) and (ii), in order to improve the adhesion between the photosensitive resin layer formed on the substrate by coating the photosensitive resin composition of the present invention on the substrate and various substrates, diaminosiloxanes such as 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 1,3-bis(3-aminopropyl)tetraphenyldisiloxane may be copolymerized during the preparation of the polyimide precursor (in the polycondensation step) (A).

In the methods (i) and (ii), after the polycondensation reaction is completed, the water-absorbing byproduct of the dehydration condensation agent coexisting in the reaction solution can be filtered and separated as needed, and then a poor solvent such as water, aliphatic lower alcohol, or a mixture thereof can be added to the reaction solution to precipitate the polymer component. Furthermore, the polymer can be purified by repeatedly performing the above-mentioned redissolution and reprecipitation operations. Subsequently, the polymer can be vacuum dried to isolate the polyimide precursor. In order to improve the degree of purification, the polymer solution can also be passed through a column filled with an anion and/or cation exchange resin swollen with a suitable organic solvent to remove ionic impurities.

In the methods (i) and (ii), when the molecular weight of the polyimide precursor (A) is measured by a polystyrene-converted weight average molecular weight based on gel permeation chromatography (GPC), the molecular weight is preferably 8,000 to 150,000, more preferably 9,000 to 50,000, and particularly preferably 18,000 to 40,000. A weight average molecular weight of 8,000 or more is preferred because the mechanical properties are good, while a weight average molecular weight of 150,000 or less is preferred because the dispersibility in the developer and the resolution of the relief pattern are good. As developing solvents for gel permeation chromatography, tetrahydrofuran and N-methyl-2-pyrrolidone are recommended. The molecular weight is obtained from a calibration curve prepared using standard monodisperse polystyrene. As the standard monodisperse polystyrene, it is recommended to select from the organic solvent standard sample STANDARD SM-105 manufactured by Showa Denko K.K.

[(B) Photosensitive agent] The photosensitive resin composition of the present invention contains a photosensitive agent. The photosensitive agent may also be a photopolymerization initiator. The photopolymerization initiator is preferred because it promotes the hardening of the relief pattern based on light irradiation. As the photopolymerization initiator, a photo-free radical polymerization initiator is preferred, and preferred ones include: benzophenone derivatives such as benzophenone, methyl o-benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, and fluorenone; acetophenone derivatives such as 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, and 1-hydroxycyclohexylphenyl ketone; 9-oxothiophenone , 2-methyl 9-oxosulfuron , 2-isopropyl 9-oxysulfide , diethyl 9-oxysulfide 9-Oxysulfuron derivatives; benzoyl derivatives such as benzoyl dimethyl ketal and benzoyl-β-methoxyethyl acetal; benzoin derivatives such as benzoin and benzoin methyl ether; 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2 -(o-benzoyl) oxime, 1,3-diphenylpropane-2-(o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropane-2-(o-benzoyl) oxime and other oximes; N-phenylglycine and other N-arylglycine; peroxides such as perchlorinated benzoyl; aromatic biimidazoles, dioscenes, α-(n-octylsulfonyloxyimino)-4-methoxybenzyl cyanide and other photoacid generators, but not limited to them. Among the above-mentioned photopolymerization initiators, oximes are more preferred in terms of photosensitivity.

The amount of the photopolymerization initiator is preferably 0.5 to 10 parts by mass, more preferably 1 to 8 parts by mass, based on 100 parts by mass of the polyimide precursor (A). The above amount is preferably 0.5 parts by mass or more from the viewpoint of photosensitivity or patterning properties, and is preferably 10 parts by mass or less from the viewpoint of the physical properties of the photosensitive resin layer after curing of the photosensitive resin composition.

[(C) Solvent] The photosensitive resin composition of the present invention contains (C) solvent (also referred to as solvent). As the solvent, a polar organic solvent is preferably used in view of the solubility of the (A) polyimide precursor. Specific examples of the solvent include N,N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, N-cyclohexyl-2-pyrrolidone, and 2-octanone. These solvents may be used alone or in combination of two or more.

In the present invention, the amount of the solvent (C) is preferably in the range of 100 to 300 parts by weight relative to 100 parts by weight of the polyimide precursor (A), depending on the desired coating film thickness and viscosity of the photosensitive resin composition.

From the viewpoint of improving the storage stability of the photosensitive resin composition, a solvent containing alcohol is preferred. The alcohols that can be suitably used are typically alcohols having an alcoholic hydroxyl group in the molecule but not having an olefinic double bond, and specific examples include: alkyl alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and t-butanol; lactic acid esters such as ethyl lactate; propylene glycol monoalkyl ethers such as propylene glycol-1-methyl ether, propylene glycol-2-methyl ether, propylene glycol-1-ethyl ether, propylene glycol-2-ethyl ether, propylene glycol-1-(n-propyl) ether, and propylene glycol-2-(n-propyl) ether; monoalcohols such as ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol-n-propyl ether; 2-hydroxyl isobutyrate; and diols such as ethylene glycol and propylene glycol. Among them, preferred are lactic acid esters, propylene glycol monoalkyl ethers, 2-hydroxy isobutyrate, and ethanol, and particularly preferred are ethyl lactate, propylene glycol-1-methyl ether, propylene glycol-1-ethyl ether, and propylene glycol-1-(n-propyl) ether.

When the solvent contains an alcohol having no olefinic double bond, the content of the alcohol having no olefinic double bond in the entire solvent is preferably 5 mass % to 50 mass %, more preferably 10 mass % to 30 mass %, based on the mass of the entire solvent. If the content of the alcohol having no olefinic double bond is 5 mass % or more, the storage stability of the photosensitive resin composition becomes good. On the other hand, if it is 50 mass % or less, the solubility of the polyimide precursor (A) becomes good.

[Free radical polymerizable monomer] In the present invention, in order to improve the resolution of the relief pattern, the photosensitive resin composition may arbitrarily contain a free radical polymerizable monomer having a photopolymerizable unsaturated bond. As such a monomer, it is preferably a (meth) acrylic compound that undergoes a free radical polymerization reaction by a photopolymerization initiator, and is not particularly limited to the following, and examples thereof include: mono- or di-acrylates or methacrylates of ethylene glycol or polyethylene glycol represented by diethylene glycol dimethacrylate and tetraethylene glycol dimethacrylate, mono- or di-acrylates or methacrylates of propylene glycol or polypropylene glycol, mono-, di- or tri-acrylates or methacrylates of glycerol, cyclohexane diacrylate or dimethacrylate, diacrylate or dimethacrylate of 1,4-butanediol, 1, Compounds such as diacrylate or dimethacrylate of 6-hexanediol, diacrylate or dimethacrylate of neopentyl glycol, mono- or diacrylate or methacrylate of bisphenol A, benzyltrimethacrylate, isobutyl acrylate or isobutyl methacrylate, acrylamide and its derivatives, methacrylamide and its derivatives, trihydroxymethylpropane triacrylate or methacrylate, di- or triacrylate or methacrylate of glycerol, di-, tri- or tetraacrylate or methacrylate of pentaerythritol and neopentyltriol, and ethylene oxide or propylene oxide adducts of these compounds. These monomers may be used alone or as a mixture of two or more.

In the present invention, the amount of the monomer having a photopolymerizable unsaturated bond is preferably 0.5 to 15 parts by weight relative to 100 parts by weight of the (A) polyimide precursor.

[Other components] The photosensitive resin composition of the present invention may further contain components other than the above-mentioned components (A) to (C) and the free radical polymerizable monomer. Examples of other components include: resin components other than (A) polyimide precursor; organic metal compounds; sensitizers; bonding aids; thermal polymerization inhibitors; azole compounds; and hindered phenol compounds.

Examples of the resin component other than the polyimide precursor (A) include polyimide, polyazole, polyazole precursor, phenolic resin, polyamide, epoxy resin, silicone resin, acrylic resin, etc. The amount of the resin component is preferably in the range of 0.01 to 20 parts by weight relative to 100 parts by weight of the polyimide precursor (A).

When a polyazole precursor is used together with the polyimide precursor (A) to prepare a positive photosensitive resin composition, a compound having a quinonediazide group, such as a compound having a 1,2-benzoquinonediazide structure or a 1,2-naphthoquinonediazide structure, can be used as a positive photosensitive material.

In the present invention, the photosensitive resin composition may contain an organic metal compound. The organic metal compound preferably contains at least one metal element selected from the group consisting of titanium and zirconium in one molecule. As the organic group, it is preferably a hydrocarbon group or a hydrocarbon group containing a heteroatom. As the organic titanium or zirconium compound that can be used, for example, an organic group bonded to a titanium atom or a zirconium atom via a covalent bond or an ionic bond can be cited.

Specific examples of organic titanium or zirconium compounds are shown in the following I) to VII): I) As a chelating compound, based on the storage stability of the photosensitive resin composition and the ability to obtain a good pattern, a compound having two or more alkoxy groups is more preferred. As chelating compounds, specific examples include: titanium bis(triethanolamine)diisopropoxide, titanium bis(2,4-pentanedioate)di(n-butanol), titanium bis(2,4-pentanedioate)diisopropoxide, titanium bis(tetramethylpimelate)diisopropoxide, titanium diisopropoxidedi(ethyl acetylacetate), and compounds in which the titanium atoms of these compounds are replaced by zirconium atoms, but are not limited to these.

II) Examples of the tetraalkoxy compound include titanium tetra(n-butanol), titanium tetraethanol, titanium tetra(2-ethylhexanol), titanium tetraisobutanol, titanium tetraisopropanol, titanium tetramethylol, titanium tetramethoxypropanol, titanium tetramethylphenol, titanium tetra(n-nonanol), titanium tetra(n-propanol), titanium tetrastearyl alcohol, titanium tetra[bis{2,2-(allyloxymethyl)butanol}], and compounds wherein the titanium atom of these compounds is substituted with a zirconium atom, but the present invention is not limited thereto.

III) Examples of the titaniumocene or zirconocene compound include, but are not limited to, titanium pentamethylcyclopentadienyltrimethoxide, titanium bis(η ⁵ -2,4-cyclopentadien-1-yl)bis(2,6-difluorophenyl)bis(η ⁵ -2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl) ...

IV) Examples of monoalkoxy compounds include, but are not limited to, titanium tri(dioctylphosphate)isopropoxide, titanium tri(dodecylbenzenesulfonate)isopropoxide, and compounds wherein the titanium atom of these compounds is replaced by a zirconium atom.

V) Examples of titanium oxide or zirconium oxide compounds include, but are not limited to, bis(glutaric acid)titanium oxide, bis(tetramethylpimelic acid)titanium oxide, phthalocyanine oxidetitanium oxide, and compounds wherein the titanium atom of these compounds is replaced by a zirconium atom.

VI) Examples of the titanium tetraacetylpyruvate or zirconium tetraacetylpyruvate compound include, but are not limited to, titanium tetraacetylpyruvate and compounds in which the titanium atom of these compounds is substituted with a zirconium atom.

VII) As the titanium ester coupling agent, for example, tri(dodecylbenzenesulfonyl)titanium isopropyl ester and the like can be mentioned, but the invention is not limited thereto.

Among the above I) to VII), from the viewpoint of exerting a better dielectric dissipation factor, the organic titanium compound is preferably at least one compound selected from the group consisting of the above I) titanium chelate compounds, II) tetraalkoxy titanium compounds, and III) titanocene compounds. Particularly preferred are titanium diisopropoxide bis(ethyl acetylacetate), titanium tetra(n-butoxide), and bis(η ⁵ -2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium.

When an organic titanium or zirconium compound is added, the amount thereof is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the resin (A).

The photosensitive resin composition may optionally contain a sensitizer to increase the photosensitivity. Examples of the sensitizer include: michler's ketone, 4,4'-bis(diethylamino)benzophenone, 2,5-bis(4'-diethylaminobenzylidene)cyclopentane, 2,6-bis(4'-diethylaminobenzylidene)cyclohexanone, 2,6-bis(4'-diethylaminobenzylidene)-4-methylcyclohexanone, 4,4'-bis(dimethylamino)chalcone, 4,4'-bis(diethylamino)chalcone, p-dimethylamine cinnamylene dihydroindanone, p-dimethylaminobenzylidene dihydroindanone, 2-(p-dimethylaminophenyl biphenyl)-benzothiazole, 2-(p-dimethylaminophenyl vinyl)benzothiazole, 2-(p-dimethylaminophenyl vinyl)isonaphthothiazole, 1,3-bis(4'-dimethylaminobenzylidene)acetone, 1,3-bis(4'-diethylaminobenzylidene)acetone, 3,3'-carbonyl-bis(7-diethylaminobenzylidene)acetone, 3-Methoxycarbonyl-7-diethylaminocoumarin, 3-ethoxycarbonyl-7-dimethylaminocoumarin, 3-benzyloxycarbonyl-7-dimethylaminocoumarin, 3-methoxycarbonyl-7-diethylaminocoumarin, 3-ethoxycarbonyl-7-diethylaminocoumarin, N-phenyl-N'-ethylethanolamine, N-phenyldiethanolamine, N-p-tolyldiethanolamine, N-phenylethanolamine, 4- isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 2-benzimidazole, 1-phenyl-5-benzyltetrazolyl, 2-benzthiazole, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzothiazole, 2-(p-dimethylaminostyryl)naphtho(1,2-d)thiazole, 2-(p-dimethylaminobenzyl)styrene, etc. These may be used alone or in combination of plural types (e.g., 2 to 5 types).

The amount of the sensitizer to be added is preferably 0.1 to 25 parts by weight relative to 100 parts by weight of the polyimide precursor (A).

In order to improve the adhesion between the film formed using the photosensitive resin composition and the substrate, the photosensitive resin composition may optionally contain an adhesion aid. Examples of the adhesion aid include: γ-aminopropyl dimethoxysilane, N-(β-aminoethyl)-γ-aminopropyl methyl dimethoxysilane, γ-glycidyloxypropyl methyl dimethoxysilane, γ-butyl propyl methyl dimethoxysilane, 3-methacryloxypropyl dimethoxymethyl silane, 3-methacryloxypropyl trimethoxysilane, dimethoxymethyl-3-piperidinylpropyl silane, diethoxy-3-glycidyloxypropyl methyl silane, N-(3-diethoxymethylsilylpropyl) succinimide , N-[3-(triethoxysilyl)propyl]phthalamide, benzophenone-3,3'-bis(N-[3-triethoxysilyl]propylamido)-4,4'-dicarboxylic acid, benzene-1,4-bis(N-[3-triethoxysilyl]propylamido)-2,5-dicarboxylic acid, 3-(triethoxysilyl)propylsuccinic anhydride, N-phenylaminopropyltrimethoxysilane and other silane coupling agents, and aluminum-based bonding agents such as tri(ethyl acetylacetate)aluminum, tri(acetylacetone)aluminum, ethyl acetylacetate diisopropylaluminum, etc. These bonding agents may be used alone or as a mixture of two or more.

Among the bonding agents, silane coupling agents are more preferably used in terms of bonding strength. The amount of the bonding agent is preferably in the range of 0.5 to 25 parts by weight relative to 100 parts by weight of the polyimide precursor (A).

In order to improve the stability of the viscosity and photosensitivity of the photosensitive resin composition when stored in a solution containing a solvent, the photosensitive resin composition may optionally contain a thermal polymerization inhibitor. As the thermal polymerization inhibitor, for example, hydroquinone, N-nitrosodiphenylamine, p-tert-butylcatechol, phenothiocyanate, N-phenylnaphthylamine, ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, 2,6-di-tert-butyl-p-methylphenol, 5-nitroso-8-hydroxyquinoline, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 2-nitroso-5-(N-ethyl-N-sulfopropylamino)phenol, N-nitroso-N-phenylhydroxylamine ammonium salt, N-nitroso-N(1-naphthyl)hydroxylamine ammonium salt, etc. These thermal polymerization inhibitors may be used alone or as a mixture of two or more.

The amount of the thermal polymerization inhibitor to be added is preferably in the range of 0.005 to 12 parts by weight relative to 100 parts by weight of the polyimide precursor (A).

For example, when a substrate comprising copper or a copper alloy is used, the photosensitive resin composition may optionally contain an azole compound in order to suppress discoloration of the substrate. Examples of the azole compound include 1H-triazole, 5-methyl-1H-triazole, 5-ethyl-1H-triazole, 4,5-dimethyl-1H-triazole, 5-phenyl-1H-triazole, 4-tert-butyl-5-phenyl-1H-triazole, 5-hydroxyphenyl-1H-triazole, phenyltriazole, p-ethoxyphenyltriazole, 5-phenyl-1-(2-dimethylaminoethyl)triazole, 5-benzyl-1H-triazole, hydroxyphenyltriazole, 1,5-dimethyltriazole, 4,5-diethyl-1H-triazole, 1H-benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl] ]-benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)-benzotriazole, 2-(3,5-di-tert-pentyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, hydroxyphenylbenzotriazole, tolyltriazole, 5-methyl-1H-benzotriazole, 4-methyl-1H-benzotriazole, 4-carboxyl-1H-benzotriazole, 5-carboxyl-1H-benzotriazole, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 1-methyl-1H-tetrazole, and the like. Particularly preferred are tolyltriazole, 5-methyl-1H-benzotriazole, and 4-methyl-1H-benzotriazole. In addition, these azole compounds may be used alone or in the form of a mixture of two or more.

The amount of the azole compound to be added is preferably 0.1 to 20 parts by weight relative to 100 parts by weight of the polyimide precursor (A), and more preferably 0.5 to 5 parts by weight from the viewpoint of photosensitivity characteristics. If the amount of the azole compound to be added is 0.1 parts by weight or more relative to 100 parts by weight of the polyimide precursor (A), discoloration of the surface of copper or copper alloy can be suppressed when the photosensitive resin composition is formed on copper or copper alloy. On the other hand, if the amount is 20 parts by weight or less, photosensitivity is excellent, so it is preferred.

In the present invention, in order to suppress discoloration on copper, the photosensitive resin composition may contain a hindered phenol compound. Examples of the hindered phenol compound include: 2,6-di-tert-butyl-4-methylphenol, 2,5-di-tert-butyl-hydroquinone, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecyl ester, 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate isooctyl ester, 4,4'-methylenebis(2,6-di-tert-butylphenol), 4,4'-thio-bis(3-methyl-6-tert-butylphenol), 4,4'-butylene-bis(3- methyl-6-tert-butylphenol), triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-phenylpropionamide), 2,2'-methylene-bis(4-methyl 6-tert-butylphenol), 2,2'-methylene-bis(4-ethyl-6-tert-butylphenol), pentaerythritol-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(3-hydroxy-2,6-dimethyl-4-isopropylbenzyl)- 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(4-sec-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(4-sec-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris[4-(1-ethylpropyl)- 3-Hydroxy-2,6-dimethylbenzyl]-1,3,5-tri-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris[4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-tri-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(3-hydroxy-2,6-dimethyl-4-phenylbenzyl)-1,3,5-tri-2,4,6-(1H,3H,5H)-trione, 1,3 ,5-tris(4-tert-butyl-3-hydroxy-2,5,6-trimethylbenzyl)-1,3,5-tris(2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-tert-butyl-5-ethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-tert-butyl-6-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-tris(2,4,6-(1H,3H,5H)-trione 4,6-(1H,3H,5H)-trione, 1,3,5-tri(4-tert-butyl-6-ethyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-tri(4-tert-butyl-5,6-diethyl-3-hydroxy-2-methylbenzyl)-1,3,5-tri(4-tert-butyl-3-hydroxy-2,5-dimethylbenzyl)-2,4,6-(1H,3H,5H)-trione, 1,3,5-tri(4-tert-butyl-5,6-diethyl-3-hydroxy-2-methylbenzyl)-1,3,5-tri(4-tert-butyl-3-hydroxy- The present invention also includes 1,3,5-tris(4-tert-butyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-5-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-tris(4-tert-butyl-5-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-tris(4-tert-butyl-2,6-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-2,6-dimethylbenzyl)-2,4,6-(1H,3H,5H)-trione, but is not limited thereto. Among them, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-2,6-dimethylbenzyl)-1,3,5-tris(4-tert-butyl-2,6-dimethylbenzyl)-2,4,6-(1H,3H,5H)-trione is particularly preferred.

The amount of the hindered phenol compound to be added is preferably 0.1 to 20 parts by weight relative to 100 parts by weight of the polyimide precursor (A), and more preferably 0.5 to 10 parts by weight from the viewpoint of photosensitivity characteristics. If the amount of the hindered phenol compound to be added is 0.1 parts by weight or more relative to 100 parts by weight of the polyimide precursor (A), for example, when a photosensitive resin composition is formed on copper or a copper alloy, discoloration and corrosion of the copper or a copper alloy can be prevented. On the other hand, if the amount is 20 parts by weight or less, photosensitivity is excellent, so it is preferred.

"Polyimide Cured Film" According to the present invention, a polyimide cured film formed from the polyimide precursor composition of the present invention is also provided. The polyimide contained in the polyimide cured film preferably has a structure represented by the following general formula (11): [Chemical 21] {In the general formula (11), _X1 and _Y1 are the same as _X1 and _Y1 in the general formula (1), and m is a positive integer}.

The polyimide contained in the polyimide cured film preferably has a structure represented by the above general formula (1) or the following general formula (5). {In the general formula (5), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n2 is an integer of 2 to 150, and _R13 is a group represented by the general formula (3) above}.

Preferred _X1 and _Y1 in the general formula (1) are also preferred in the polyimides of the general formulas (11) and (5) for the same reasons. Preferred structures of the general formula (3) are also preferred as structures of _R13 in the polyimide of the general formula (5) for the same reasons. The number of repeating units m in the general formula (11) and the number of repeating _{units n2} in the general formula (5) are not particularly limited and can be integers of 2 to 150, respectively and independently.

Since the side chain of the polyimide precursor (A) has an amide structure, a polyimide having a precursor structure can be obtained after heat curing. The ring closure rate after heat curing is preferably 10 mol% to 95 mol%. In the present invention, the so-called "precursor structure" refers to a structure in which at least one of the two amide ring structures contained in the repeating unit of the polyimide has been ring-opened. In the present invention, the so-called "ring closure rate" refers to the ratio of the molar amount of the repeating unit having the precursor structure based on the total molar amount of the repeating unit. From the viewpoint of tensile elongation, the lower limit of the closed ring rate is preferably 10 mol% or more, more preferably 30 mol% or more, further preferably 50 mol% or more, further preferably 60 mol% or more, and particularly preferably 70 mol% or more. The upper limit of the closed ring rate that can be combined with the lower limits is preferably 95 mol% or less from the viewpoint of adhesion, and is preferably 92 mol% or less from the viewpoint of low dielectric loss tangent.

"Method for producing polyimide cured film" According to the present invention, a polyimide cured film formed by curing the photosensitive resin composition of the present invention and a method for producing the same are also provided. The method for producing a polyimide cured film of the present invention comprises the following steps (1) to (5): (1) coating the photosensitive resin composition containing the polyimide precursor of the present invention on a substrate to form a photosensitive resin layer on the substrate; (2) heating and drying the obtained photosensitive resin layer; (3) exposing the heated and dried photosensitive resin layer; (4) developing the exposed photosensitive resin layer; and (5) heating the developed photosensitive resin layer to form a polyimide cured film.

The photosensitive resin composition used in the method for producing a polyimide cured film preferably comprises a polyimide precursor, a photosensitive agent, and a solvent. The photosensitive resin composition more preferably comprises a photo-radical polymerization initiator as the photosensitive agent. Moreover, the photosensitive resin composition is further preferably a negative type. For details on the preferred aspects of the photosensitive resin composition, refer to the column "Photosensitive resin composition" above.

The specific steps in the method for producing a polyimide cured film can be carried out according to the steps (1) to (5) of the method for producing a cured film described above. Each step is described below.

[(1) Photosensitive resin layer forming step] In this step, the photosensitive resin composition of the present invention is coated on a substrate to form a photosensitive resin layer. As a coating method, a method conventionally used for coating a photosensitive resin composition can be used, such as a coating method using a rotary coater, a rod coater, a doctor blade coater, a curtain coater, a screen printer, etc., a spray coating method using a spray coater, etc.

[(2) Heating and drying step] The photosensitive resin layer containing the photosensitive resin composition is heated and dried as needed. As drying methods, for example, air drying, heat drying using an oven or a heating plate, vacuum drying, etc. can be used. In addition, the drying of the coating is preferably carried out under conditions such that the (A) polyimide precursor in the photosensitive resin composition does not undergo imidization. Specifically, when air drying or heat drying is carried out, the drying can be carried out under conditions of 20°C to 140°C and 1 minute to 1 hour. In this way, a photosensitive resin layer can be formed on the substrate.

[(3) Exposure step] In this step, the photosensitive resin layer that has undergone the above-mentioned (2) step is exposed using an exposure device such as a contact aligner, a mirror projection exposure machine, a stepper, etc., through a photomask or a reticle having a pattern, or directly using an ultraviolet light source.

Thereafter, in order to improve photosensitivity, etc., a post-exposure bake (PEB) and/or a pre-development bake at any combination of temperature and time may be performed as needed. The range of baking conditions is preferably 40°C to 120°C, and the time is preferably 10 seconds to 240 seconds, but it is not limited to this range as long as it does not hinder the properties of the photosensitive resin composition. The imidization rate of the polyimide precursor does not change before and after baking.

[(4) Development step] In this step, the exposed photosensitive resin layer is developed to form a relief pattern. In this step, when the photosensitive resin composition is negative, the unexposed portion of the exposed photosensitive resin layer is developed and removed. As a developing method for developing the exposed (irradiated) photosensitive resin layer, any method can be selected from previously known photoresist developing methods, such as a rotary spray method, a liquid coating method, and an immersion method accompanied by ultrasonic treatment. In addition, after development, in order to adjust the shape of the relief pattern, post-development baking at any combination of temperature and time can be implemented as needed. As a developer for developing, for example, a good solvent for a negative photosensitive resin composition or a combination of the good solvent and a poor solvent is preferred. As a good solvent, for example, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N,N-dimethylacetamide, cyclopentanone, cyclohexanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, etc. are preferred. As a poor solvent, for example, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol methyl ether acetate, and water are preferred. When a good solvent and a poor solvent are used in combination, it is preferred to adjust the ratio of the poor solvent to the good solvent according to the solubility of the polymer in the negative photosensitive resin composition. In addition, two or more solvents, for example, several solvents, may be used in combination.

[(5) Polyimide hardening film formation step] In this step, the relief pattern obtained by the above-mentioned development is heated to disperse the photosensitive components, and the (A) polyimide precursor is imidized to convert it into a hardened relief pattern containing polyimide. As a method of heat hardening, various methods can be selected, such as a method using a heating plate, a method using an oven, and a method using a temperature-raising oven with a settable temperature control program. The heating temperature can be, for example, 150°C to 400°C, preferably 150°C to 230°C. Regarding the heating time, the heating can be carried out under the condition of 30 minutes to 5 hours. As the ambient gas during heat hardening, air can be used, and inert gases such as nitrogen and argon can also be used.

"Semiconductor device" According to the present invention, a semiconductor device can be provided, which has a polyimide cured film (hardened embossed pattern) obtained by using the photosensitive resin composition of the present invention and by the above-mentioned method for manufacturing a polyimide cured film. Therefore, according to the present invention, a semiconductor device is also provided, which has a substrate as a semiconductor element, and a polyimide cured film (hardened embossed pattern) formed on the substrate by the above-mentioned method for manufacturing a polyimide cured film. In addition, the photosensitive resin composition of the present invention can also be suitably used in a method for manufacturing a semiconductor device that uses a semiconductor element as a substrate and includes the above-mentioned method for manufacturing a polyimide cured film as part of the steps. The semiconductor device of the present invention can be manufactured by forming a polyimide cured film (cured convex pattern) formed by the above-mentioned polyimide cured film manufacturing method as a surface protective film, an interlayer insulating film, a redistribution insulating film, a flip chip device protective film, or a protective film for a semiconductor device with a bump structure, and combining it with a known semiconductor device manufacturing method. The semiconductor device of the present invention preferably includes the polyimide cured film of the present invention as a redistribution insulating film.

"Display device" Using the photosensitive resin composition of the present invention, a display device is also provided, which has a display element and a cured film disposed on the upper portion of the display element, and the cured film is the above-mentioned cured embossed pattern. Here, the cured embossed pattern can be laminated directly in contact with the display element, or can be laminated via other layers. For example, the cured film can include surface protection films, insulating films, and planarization films of TFT liquid crystal display elements and color filter elements, protrusions for MVA (Multi-domain Vertical Alignment) type liquid crystal display devices, and partitions for cathodes of organic EL elements.

In addition to being used in the semiconductor devices described above, the photosensitive resin composition of the present invention can also be used for interlayer insulation of multilayer circuits, covering coatings of flexible copper-clad boards, solder resists, and liquid crystal alignment films. [Examples]

The following specifically describes the Examples, Comparative Examples, and Preparation Examples, but the present invention is not limited thereto. In the Examples, Comparative Examples, and Preparation Examples, the physical properties of the photosensitive resin composition were measured and evaluated according to the following methods.

[Measurement and evaluation methods]  (1) Weight average molecular weight  The weight average molecular weight (Mw) of each resin was measured by gel permeation chromatography (standard polystyrene conversion). The column used in the measurement was "Shodex 805M/806M series" manufactured by Showa Denko K.K., the standard monodisperse polystyrene was "Shodex STANDARD SM-105" manufactured by Showa Denko K.K., the developing solvent was N-methyl-2-pyrrolidone, and the detector was "Shodex RI-930" manufactured by Showa Denko K.K.

(2) Adhesion of substrates A 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) was sputter-coated with Ti with a thickness of 200 nm and Cu with a thickness of 400 nm in sequence using a sputtering device (L-440S-FHL, manufactured by CANON ANELVA). Then, a photosensitive resin composition prepared by the following method was spin-coated on the wafer using a coating developer (D-Spin60A, manufactured by SOKUDO). The film was dried at 110°C on a hot plate for 3 minutes to form a photosensitive resin layer with a thickness of about 15 μm. The photosensitive resin layer was irradiated with an energy of 800 mJ/ ^cm2 using an AP-200 (manufactured by Ultratech) equipped with an i-ray filter using a mask with a test pattern.

The wafer having the embossed pattern formed on Cu was subjected to a heating treatment at 230°C for 2 hours in a nitrogen environment using a temperature-programmed curing furnace (VF-2000, manufactured by Koyo Lindberg), thereby obtaining a cured film of a resin having a thickness of about 10 μm on Cu.

On the heat-cured film, a test piece was made by 180-degree peeling according to the adhesive-peeling test of JIS K 6854-2 standard. The substrate adhesion was evaluated by 180-degree peeling strength using RTG-1210 manufactured by A&D Co., Ltd. The sample was made with a width of 5 mm, and the average value of 5 samples was measured as the adhesion strength (N/mm).

(3) Evaluation of copper substrate corrosion: A 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) was sputter-plated with 200 nm thick Ti and 400 nm thick Cu in sequence using a sputter plating device (L-440S-FHL, manufactured by CANON ANELVA). Subsequently, a photosensitive resin composition prepared by the following method was spin-coated on the wafer using a coating developer (D-Spin60A, manufactured by SOKUDO), and dried by heating at 110°C on a heating plate for 3 minutes to form a photosensitive resin layer with a thickness of approximately 15 μm. Next, the photosensitive resin layer was spray developed using cyclopentanone as a developer using a coating developer (D-Spin 60A, manufactured by SOKUDO), and the photosensitive resin layer was removed by rinsing with propylene glycol methyl ether acetate. The color tone of the wafer before coating and after removing the photosensitive resin layer was compared by visual observation and an optical microscope at 200 times. If no color change was observed in either, it was considered "no" color change, and if color change was observed in either, it was considered "yes" color change.

(4) Tensile elongation A 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) was sputter-coated with aluminum (Al) to a thickness of 100 nm using a sputter coating device (L-440S-FHL, manufactured by CANON ANELVA) to prepare a sputter-coated Al wafer substrate. A photosensitive resin composition was spin-coated on the sputter-coated Al wafer substrate using a spin coating device (D-spin60A, manufactured by SOKUDO) in such a way that the film thickness after heat curing was about 10 μm, and then heated and dried at 110°C for 180 seconds to produce a spin-coated film. After that, the whole surface of the wafer was exposed to ghi radiation with an exposure dose of 600 mJ/ ^cm2 using an alignment machine (PLA-501F, manufactured by Canon), and then heated at 230°C for 2 hours in a nitrogen environment using a temperature-programmed curing furnace (VF-2000, manufactured by Koyo Lindberg) to obtain a hardened polyimide coating. After that, the polyimide coating was cut into short strips with a width of 3 mm using a dicing machine (DAD3350, manufactured by DISCO), and then peeled from the silicon wafer using 10% hydrochloric acid to obtain a polyimide tape. The tensile elongation (%) of the obtained polyimide tape was measured using a tensile testing machine (UTM-II-20, manufactured by Orientec) according to ASTM D882-09.

(5) Measurement of relative dielectric constant (Dk) and dielectric dissipation factor (Df) Aluminum (Al) with a thickness of 100 nm was sputter-coated on a 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) using a sputter coating device (L-440S-FHL, manufactured by CANON ANELVA) to prepare a sputter-coated Al wafer substrate. A photosensitive resin composition was spin-coated on the sputter-coated Al wafer substrate using a spin coating device (D-spin60A, manufactured by SOKUDO) and heated and dried at 110°C for 180 seconds to prepare a spin-coated film. After that, the whole surface was exposed to ghi radiation with an exposure amount of 600 mJ/ ^cm2 using an alignment machine (PLA-501F, manufactured by Canon Inc.), and a heat curing treatment was performed at 230°C for 2 hours in a nitrogen environment using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B) to prepare a cured film. The film thickness of the cured film was measured by the following method. The cured film was cut into 80 mm in length and 60 mm in width, or 40 mm in length and 30 mm in width using a dicing machine (manufactured by DISCO, model name DAD-2H/6T), and was immersed in a 10% hydrochloric acid aqueous solution and peeled off from the silicon wafer to prepare a film sample.

For the film sample, the relative dielectric constant (Dk) and dielectric loss factor (Df) at 40 GHz were measured by the resonator perturbation method. The details of the measurement method are as follows. (Measurement method) Perturbation method Split cylinder resonator method (Device structure) Network analyzer: PNA network analyzer E5224B (manufactured by Agilent technologies) Split cylinder resonator: CR-740 (manufactured by Kanto Electronics Application Development Co., Ltd., measurement frequency: about 40 GHz)

(6) Calculation of the highest occupied molecular orbital (HOMO) energy of the side chain The highest occupied molecular orbital (HOMO) energy of the side chain was calculated as a structure in which R ₁ and R ₂ in the above general formula (1) have hydrogen atoms. The structure optimization was performed by the EF (Eigen Following) method using the quantum chemical calculation software MOPAC. The molecular orbital energy calculation was performed using the semi-empirical molecular orbital method AM1 using the structure obtained by the above structural optimization. The HOMO energy (eV) obtained by the above molecular orbital energy calculation was used as H _sd .

(7) Measurement of closed-loop rate A 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) was sputter-coated with Ti having a thickness of 200 nm and Cu having a thickness of 400 nm in sequence using a sputtering device (L-440S-FHL, manufactured by CANON ANELVA). Subsequently, the photosensitive resin composition prepared by the methods of the embodiments and comparative examples was spin-coated on the wafer using a coating developer (D-Spin60A, manufactured by SOKUDO), and heated and dried on a hot plate at 110°C for 3 minutes to form a photosensitive resin layer having a thickness of about 10 μm. The photosensitive resin layer was irradiated with 800 mJ/cm2 of energy using an AP-200 (manufactured by Ultratech) equipped with an i-ray filter using a mask with a test pattern. The wafer with the embossed pattern formed on Cu was heated at 230°C for ² hours in a nitrogen environment using a temperature-programmed curing furnace (VF-2000, manufactured by Koyo Lindberg) to obtain a cured film of about 7 μm thick resin on Cu.

The cured film was measured by ATR-FTIR measuring device (Nicolet Continuum, manufactured by Thermo Fisher Scientific) using Si prism in the measuring range of 4000-700 cm ^-1 and 50 times. The peak height of the cured film near 1380 cm ^-1 (1350-1450 cm ^-1 , the peak with the largest peak intensity when multiple peaks exist) was divided by the peak height near 1500 cm ^-1 (1460-1550 cm ^-1 , the peak with the largest peak intensity when multiple peaks exist) and the obtained value was defined as "230°C cured film imidization index". Then, the photosensitive resin layer was cured at 350°C, and the imidization index of the obtained cured film was measured in the same manner. The obtained value was taken as the "imidization index of the cured film at 350°C", and the closed ring rate (%) was calculated by the following formula. Closed ring rate (%) = (imidization index of the cured film at 230°C / imidization index of the cured film at 350°C) × 100

(8) Storage stability: After the photosensitive resin composition was prepared, the state after stirring at room temperature (23.0±0.5℃, relative humidity 50±10%) for 33 days was evaluated. As the evaluation result, the one in the overall mixed state was regarded as "good", and the one in which phase separation occurred in the photosensitive resin composition was regarded as "bad".

(9) Amine side chain ratio The amide side chain ratio of each resin was measured using a nuclear magnetic resonance spectrometer (NMR) device. The device used for the measurement was ECS400 (manufactured by DELTA), and a ¹ H NMR spectrum was obtained. The integrated value of the peak derived from the aromatic structure was taken as the "peak value of the aromatic group", and the integrated value of the peak derived from the amide side chain was taken as the "peak value of the amide side chain". The amide side chain ratio (%) was calculated by the following formula. Amine side chain ratio (%) = (peak value of amide side chain/peak value of aromatic group) × 100

[(A) Production of polyimide precursor]  <Production Example 1> (Synthesis of (A) polyimide precursor (polymer A-1))  Put 155.1 g of 4,4'-oxydiphthalic anhydride (ODPA) and 400 ml of γ-butyrolactone in a 2-liter separable flask, and add 19.1 g of 2-(tert-butylamino)ethyl methacrylate while stirring at room temperature. After the heat caused by the reaction subsides, add 120.6 g of 2-hydroxyethyl methacrylate (HEMA) and 79.1 g of pyridine to obtain a reaction mixture. After the heat caused by the reaction subsides, cool to room temperature and let stand for 16 hours.

Then, under ice-cooling, a solution prepared by dissolving 206.3 g of dicyclohexylcarbodiimide (DCC) in 180 ml of γ-butyrolactone was added to the reaction mixture over 40 minutes while stirring, and then a suspension prepared by suspending 93.0 g of 4,4'-oxydiphenylamine (ODA) in 350 ml of γ-butyrolactone was added over 60 minutes while stirring. Furthermore, after stirring at room temperature for 2 hours, 30 ml of ethyl alcohol was added, and after stirring for 1 hour, 400 ml of γ-butyrolactone was added. The precipitate produced in the reaction mixture was removed by filtration to obtain a reaction solution.

The obtained reaction solution was added to 3 liters of ethyl alcohol to generate a precipitate containing a crude polymer. The generated crude polymer was filtered and dissolved in 1.5 liters of tetrahydrofuran to obtain a crude polymer solution. The obtained crude polymer solution was purified using an anion exchange resin ("Amberlyst ^TM 15" manufactured by Organo Co., Ltd.) to obtain a polymer solution. The obtained polymer solution was added dropwise to 28 liters of water to precipitate the polymer, and the obtained precipitate was filtered and vacuum dried to obtain a powdered polymer A-1. The weight average molecular weight (Mw) of the polymer A-1 was measured and the result was 20,000.

<Production Example 2> (Synthesis of polyimide precursor (polymer A-2)) In the above-mentioned Production Example 1, 179.6 g of 2,2-bis{4-(4-aminophenoxy)phenyl}propane (BAPP) was used instead of 93.0 g of ODA. Except for this, the reaction was carried out in the same manner as described in Production Example 1 to obtain polymer A-2. The weight average molecular weight (Mw) of the polymer A-2 was measured and the result was 24,000.

<Production Example 3> (Synthesis of polyimide precursor (polymer A-3)) In the above-mentioned Production Example 1, 161.2 g of 4,4'-bis(4-aminophenoxy)biphenyl (BAPB) was used instead of 93.0 g of ODA. Except for this, the reaction was carried out in the same manner as described in Production Example 1 to obtain polymer A-3. The weight average molecular weight (Mw) of the polymer A-3 was measured and the result was 22,000.

<Production Example 4> (Synthesis of polyimide precursor (polymer A-4)) In the above-mentioned Production Example 1, 94.4 g of m-tolidine was used instead of 93.0 g of ODA. The same reaction was carried out as described in Production Example 1, thereby obtaining polymer A-4. The weight average molecular weight (Mw) of the polymer A-4 was measured and the result was 20,000.

<Production Example 5> (Synthesis of polyimide precursor (polymer A-5)) In the above-mentioned Production Example 1, the 2-(tert-butylamino)ethyl methacrylate used was replaced by 47.7 g instead of 19.1 g, and the HEMA used was replaced by 100.5 g instead of 120.6 g. Except for this, the reaction was carried out in the same manner as described in Production Example 1 to obtain polymer A-4. The weight average molecular weight (Mw) of the polymer A-5 was measured and the result was 19,000.

<Production Example 6> (Synthesis of polyimide precursor (polymer A-6)) In the above-mentioned Production Example 1, 14.7 g of 2-aminopropyl methacrylate was used instead of 19.1 g of 2-(tert-butylamino)ethyl methacrylate. Except for this, the same reaction was carried out as described in Production Example 1 to obtain polymer A-6. The weight average molecular weight (Mw) of the polymer A-6 was measured and the result was 20,000.

<Production Example 7> (Synthesis of polyimide precursor (polymer A-7)) 155.1 g of 4,4'-oxydiphthalic anhydride (ODPA) was placed in a 2-liter separable flask, 134.0 g of 2-hydroxyethyl methacrylate (HEMA) and 400 ml of γ-butyrolactone were added, and 79.1 g of pyridine was added while stirring at room temperature to obtain a reaction mixture. After the heat caused by the reaction subsided, the mixture was cooled to room temperature and then allowed to stand for 16 hours.

Then, under ice-cooling, a solution prepared by dissolving 206.3 g of dicyclohexylcarbodiimide (DCC) in 180 ml of γ-butyrolactone was added to the reaction mixture while stirring for 40 minutes, and then a suspension prepared by suspending 93.0 g of 4,4'-oxydiphenylamine (ODA) in 350 ml of γ-butyrolactone was added while stirring for 60 minutes. Furthermore, after stirring at room temperature for 2 hours, 30 ml of ethyl alcohol was added, and after stirring for 1 hour, 400 ml of γ-butyrolactone was added. The precipitate produced in the reaction mixture was removed by filtration to obtain a reaction solution.

The obtained reaction solution was added to 3 liters of ethyl alcohol to generate a precipitate containing a crude polymer. The generated crude polymer was filtered and dissolved in 1.5 liters of tetrahydrofuran to obtain a crude polymer solution. The obtained crude polymer solution was purified using an anion exchange resin ("Amberlyst ^TM 15" manufactured by Organo Co., Ltd.) to obtain a polymer solution. The obtained polymer solution was added dropwise to 28 liters of water to precipitate the polymer, and the obtained precipitate was filtered and vacuum dried to obtain a powdered polymer A-7. The weight average molecular weight (Mw) of the polymer A-7 was measured and the result was 22,000.

<Production Example 8> (Synthesis of polyimide precursor (polymer A-8))  In a nitrogen environment, 155.1 g of 4,4'-oxydiphthalic anhydride (ODPA) and 400 ml of γ-butyrolactone were placed in a 2-liter separable flask, and then a suspension obtained by suspending 98.1 g of 4,4'-oxydiphenylamine (ODA) in 350 ml of γ-butyrolactone was added while stirring for 60 minutes. Furthermore, the mixture was stirred at room temperature for 2 hours to obtain a polyimide solution.

0.01 g of p-methoxyphenol was added to the polyamine solution and stirred at 60°C to dissolve it. After sufficient dissolution, 159.8 g of isocyanatoethyl methacrylate was added dropwise to the reaction solution and reacted at 60°C for 2 hours to obtain a polymer solution. The obtained polymer solution was added dropwise to 28 liters of water to precipitate the polymer. The obtained precipitate was filtered and vacuum dried to obtain a powdered polymer A-8. The weight average molecular weight (Mw) of the polymer A-8 was measured to be 26,000.

<Production Example 9> (Synthesis of polyimide precursor (polymer A-9)) In the above-mentioned Production Example 1, the 2-(tert-butylamino)ethyl methacrylate used was replaced by 152.7 g, and the HEMA used was replaced by 26.8 g instead of 120.6 g. Except for this, the reaction was carried out in the same manner as described in Production Example 1 to obtain polymer A-9. The weight average molecular weight (Mw) of the polymer A-9 was measured and the result was 16,000.

<Production Example 10> (Synthesis of polyimide precursor (polymer A-10)) In the above-mentioned Production Example 1, 16.8 g of 2-aminophenyl 2-acrylate was used instead of 19.1 g of 2-(tert-butylamino)ethyl methacrylate. The same reaction was carried out as described in Production Example 1, thereby obtaining polymer A-10. The weight average molecular weight (Mw) of the polymer A-10 was measured and the result was 20,000.

<Production Example 11> (Synthesis of polyimide precursor (polymer A-11)) In the above-mentioned Production Example 1, 16.8 g of 4-aminophenyl 2-acrylate was used instead of 19.1 g of 2-(tert-butylamino)ethyl methacrylate. The same reaction was carried out as described in Production Example 1, thereby obtaining polymer A-11. The weight average molecular weight (Mw) of the polymer A-11 was measured and the result was 20,000.

[Preparation of photosensitive resin composition] The following compounds were used in the examples and comparative examples. Photopolymerization initiator B-1: TR-PBG-305 (manufactured by Changzhou Qiangli Electronics Co., Ltd.) Solvent C-1: γ-butyrolactone (GBL) Solvent C-2: dimethyl sulfoxide (DMSO)

<Example 1> Using polyimide precursor A-1, a negative photosensitive resin composition was prepared by the following method, and the prepared composition was evaluated. A-1 (100 g) as a polyimide precursor (A), B-1 (5 g) as a photopolymerization initiator (B), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-tris(2,4,6-(1H,3H,5H)-trione (1.5 g), 8-azaadenine (0.2 g), and N-[3-(triethoxysilyl)propyl]phthalamide (1.5 g) were dissolved in C-1 (180 g) and C-2 (20 g) as a solvent (C). A small amount of GBL was then added to adjust the viscosity of the obtained solution to about 40 poise, thereby preparing a negative photosensitive resin composition. The composition was evaluated according to the above method. The results are shown in Table 1 below.

<Examples 2 to 8, Comparative Examples 1 to 3>  Prepared according to the blending ratio shown in Table 1 below, the same evaluation as in Example 1 was performed. The results are shown in Table 1 below.

[Table 1] Table 1 Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Embodiment 8 Comparison Example 1 Comparison Example 2 Comparison Example 3 (A) Polyimide precursor (g) A-1 100 A-2 100 A-3 100 A-4 100 A-5 100 A-6 100 A-7 100 A-8 100 A-9 100 A-10 100 A-11 100 (B) Photopolymerization initiator (g) B-1 5 5 5 5 5 5 5 5 5 5 5 (C)Solvent (g) C-1 180 180 180 180 180 180 180 180 180 180 180 C-2 20 20 20 20 20 20 20 20 20 20 20 Side chain HOMO (eV) -9.4706 -9.4706 -9.4706 -9.4706 -9.4706 -9.4706 -9.8807 -8.5065 - -9.9337 -8.4222 Amide side chain ratio 10% 10% 10% 10% 25% 80% 10% 10% 0% 32% 10% Substrate adhesion [N/mm] 0.48 0.44 0.58 0.54 0.54 0.57 0.40 0.51 0.39 0.58 0.57 Copper substrate corrosion without without without without without without without without without have without Tensile elongation 45% 45% 70% 70% 40% 25% 45% 20% 50% 4% 7% Dk(40 GHz) 3.26 3.31 2.95 2.96 3.24 3.22 3.26 3.26 3.26 3.21 3.26 Df(40 GHz) 0.012 0.012 0.009 0.009 0.011 0.010 0.012 0.012 0.015 0.010 0.012 Preserve stability good good good good good good good good good bad good

As shown in Table 1, in Examples 1 to 8, a relatively high adhesion of 0.4 N/mm or more adhesion strength was shown, and the tensile elongation was 20% or more. In Comparative Example 1, the adhesion strength decreased, and in Comparative Example 2, in addition to the decrease in tensile elongation, corrosion on the copper substrate was also observed. In Comparative Example 2, a large number of carboxylic acid groups remained in the side chains of the polymer, so corrosion of the copper substrate and a decrease in elongation occurred, and it was considered that the storage stability was poor. In Comparative Example 3, when the ring was closed by heating, the main chain was detached, the molecular weight was reduced, and it was considered that the tensile elongation was reduced. [Industrial Applicability]

By using the photosensitive resin composition of the present invention, a cured film can be provided which exhibits high substrate adhesion, has a low dielectric loss factor, can suppress corrosion of a copper substrate, and has a high tensile elongation. Therefore, the photosensitive resin composition of the present invention can be suitably used in the field of photosensitive materials useful for the manufacture of electrical and electronic materials such as semiconductor devices and multi-layer wiring boards.

Claims (13)

A photosensitive resin composition comprises (A) a polyimide precursor, (B) a photosensitizer, and (C) a solvent, wherein the polyimide precursor (A) comprises a structure represented by the following general formula (1):

{In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, _R1 and _R2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms, wherein at least one of _R1 and _R2 is an organic group having a polymerizable group and a nitrogen atom, and the molecular orbital energy Hsd (eV) of the highest occupied molecular orbital (HOMO) of the structure of _R1 or _R2 having a polymerizable group and a nitrogen _atom satisfies -9.9≦ _Hsd ≦-8.5}. The photosensitive resin composition of claim 1, wherein in the general formula (1), _R1 and _R2 are independently selected from the group consisting of a hydrogen atom, an organic group represented by the following general formula (2), and an organic group represented by the following general formula (3),

{In the general formula (2), R ₃ , R ₄ and R ₅ are independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and R ₆ is a divalent organic group having 1 to 10 carbon atoms or a divalent organic group containing a ring structure},

{In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1 valent organic group having 2 to 10 carbon atoms or an m ₁ +1 valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4}. A photosensitive resin composition comprises (A) a polyimide precursor, (B) a photosensitizer, and (C) a solvent, wherein the polyimide precursor (A) comprises a structure represented by the following general formula (1):

{In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, _R1 and _R2 are each independently a group selected from the group consisting of a hydrogen atom, an organic group represented by the following general formula (2), and an organic group represented by the following general formula (3), wherein the above-mentioned (A) polyimide precursor comprises both structures represented by the following general formula (2) and the following general formula (3)},

{In the general formula (2), R ₃ , R ₄ and R ₅ are independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and R ₆ is a divalent organic group having 1 to 10 carbon atoms or a divalent organic group containing a ring structure},

{In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1 valent organic group having 2 to 10 carbon atoms or an m ₁ +1 valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4}. The photosensitive resin composition of claim 1, wherein in the general formula (1), at least one of _R1 and _R2 is an organic group represented by the following general formula (3),

{In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1 valent organic group having 2 to 10 carbon atoms or an m ₁ +1 valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4}. The photosensitive resin composition of claim 3 or 4, wherein the content of the organic group of the general formula (3) in the polyimide precursor is 5 mol% to 90 mol% relative to the total molar amount of _R1 and _R2 in the general formula (1). The photosensitive resin composition of claim 3 or 4, wherein in the general formula (3), R ₁₀ is a monovalent organic group having 1 to 10 carbon atoms. The photosensitive resin composition of claim 3 or 4, wherein in the general formula (3), R ₁₀ is a monovalent organic group having 1 to 5 carbon atoms. The photosensitive resin composition of claim 3 or 4, wherein the general formula (3) is represented by the following structure:

{In the general formula (4), R ₂₁ , R ₂₂ , and R ₂₃ are each independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₂₄ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and R ₂₅ is a divalent organic group having 2 to 10 carbon atoms}. The photosensitive resin composition of any one of claims 1 to 4, wherein in the above general formula (1), _Y1 comprises a structure represented by the following general formula (Y1):

{In the general formula (Y1), Rz is independently a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a is independently an integer of 0 to 4, A is independently an oxygen atom or a sulfur atom, and B is a single bond or the following formula:

1 of them}. A polyimide cured film having a closed ring rate of 10% to 95% and comprising at least one structure selected from the following general formula (1) or (5):

{In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, and _R1 and _R2 are groups represented by the following general formula (3)},

{In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1 valent organic group having 2 to 10 carbon atoms or an m ₁ +1 valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4},

{In the general formula (5), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n2 is an integer of 2 to 150, and _R13 is a group represented by the following general formula (3)},

{In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1 valent organic group having 2 to 10 carbon atoms or an m ₁ +1 valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4}. As in claim 10, the polyimide cured film is an insulating film for rewiring. A method for preparing a photosensitive resin composition comprises the following steps: (A) a synthesis step of a polyimide precursor; and a step of preparing the photosensitive resin composition in a manner comprising (A) the polyimide precursor, (B) a photosensitizer, and (C) a solvent; the synthesis step comprises the following steps: reacting tetracarboxylic dianhydride with an amide group-introducing compound to obtain a photosensitive resin composition; A step of obtaining an acid/amide body; a step of reacting the acid/amide body with an alcohol to obtain an acid/amide/ester body; and a step of subjecting the acid/amide/ester body to a condensation reaction with a diamine monomer to synthesize a (A) polyimide precursor having an amide structure and an ester structure; and the (A) polyimide precursor has three or more amide structures per repeating unit. A method for producing a polyimide cured film comprises the following steps (1) to (5): (1) coating a photosensitive resin composition comprising a polyimide precursor on a substrate to form a photosensitive resin layer on the substrate; (2) heating and drying the obtained photosensitive resin layer; (3) exposing the heated and dried photosensitive resin layer; (4) developing the exposed photosensitive resin layer; and (5) heating the developed photosensitive resin layer to form a polyimide cured film. The polyimide precursor comprises a structure represented by the following general formula (1):

{In the general formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer of 2 to 150, _R1 and _R2 are each independently a group selected from the group consisting of a hydrogen atom, an organic group represented by the following general formula (2), and an organic group represented by the following general formula (3), wherein the polyimide precursor comprises both the structures represented by the following general formula (2) and the following general formula (3)},

{In the general formula (2), R ₃ , R ₄ and R ₅ are independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and R ₆ is a divalent organic group having 1 to 10 carbon atoms or a divalent organic group containing a ring structure},

{In the general formula (3), R ₇ , R ₈ , and R ₉ are independently a hydrogen atom or a monovalent organic group having 1 to 5 carbon atoms, R ₁₀ is a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, R ₁₁ is an m ₁ +1 valent organic group having 2 to 10 carbon atoms or an m ₁ +1 valent organic group containing a ring structure, R ₁₂ is a divalent organic group having 1 to 5 carbon atoms which may contain a heteroatom, and m ₁ is an integer of 1 to 4}.