WO2024095573A1

WO2024095573A1 - Polyimide precursor and resin composition

Info

Publication number: WO2024095573A1
Application number: PCT/JP2023/030381
Authority: WO
Inventors: 真吾田原; 修学串田
Original assignee: Ｈｄマイクロシステムズ株式会社
Priority date: 2022-11-02
Filing date: 2023-08-23
Publication date: 2024-05-10
Also published as: TW202419527A

Abstract

This polyimide precursor is at least one selected from the group consisting of a polyamic acid and a polyamic acid ester. The polyimide precursor includes a structural unit (A) derived from a tetracarboxylic dianhydride and a structural unit (B) derived from a diamine compound, and also includes a compound having a non-volatile crosslinking group in a main chain end thereof, wherein the following (1) or (2) is satisfied. (1) The structural unit (A) includes a structural unit (A1-1) in which two acid anhydride groups contained in the tetracarboxylic dianhydride are not bonded to an aromatic ring. (2) The structural unit (A) includes a structural unit (A1-2) which does not contain an aromatic ring, or in which the ratio of the number of aromatic rings contained in the tetracarboxylic dianhydride to the molecular weight of the tetracarboxylic dianhydride is less than 0.0068.

Description

Polyimide precursor and resin composition

This disclosure relates to a polyimide precursor and a resin composition.

In recent years, organic materials having high heat resistance, such as polyimide resins, have been widely used as protective film materials for semiconductor integrated circuits (LSIs) (see, for example, Patent Document 1).
Such a protective film (cured film) using a polyimide resin can be obtained by applying a polyimide precursor or a resin composition containing a polyimide precursor onto a substrate, drying the applied resin film, and then heating the resulting film to cure it.

JP 2016-199662 A

In applications such as organic passivation layers for semiconductors, there is a demand for cured polyimides that have high elasticity, low stress, high resolution, and other properties.
It is known that the composition of the resin composition containing the polyimide precursor, the molecular weight of the polyimide precursor, the esterification rate, and other properties of the polyimide precursor affect the physical properties of the cured product.
For example, the higher the molecular weight of the polyimide precursor, the more likely the cured polyimide will have high elasticity and low stress. However, when a polyimide precursor with a high molecular weight is used, the developability and pattern resolution in the lithography process are reduced, so there is a trade-off. Therefore, in addition to the method of using a polyimide precursor with a high molecular weight, there is a demand for a polyimide precursor and a resin composition containing the same that can reduce stress when cured.

The present disclosure has been made in consideration of the above-mentioned conventional circumstances, and aims to provide a polyimide precursor that can reduce stress when cured, and a resin composition containing the same.

Specific means for achieving the above object are as follows.
<1> A polyimide precursor which is at least one selected from the group consisting of polyamic acids and polyamic acid esters,
the polyimide precursor contains a structural unit (A) derived from a tetracarboxylic dianhydride and a structural unit (B) derived from a diamine compound, and contains a compound having a nonvolatile crosslinking group at a main chain terminal;
The structural unit (A) is a polyimide precursor that includes a structural unit (A1-1) in which the two acid anhydride groups contained in the tetracarboxylic dianhydride are not bonded to an aromatic ring.
<2> A polyimide precursor which is at least one selected from the group consisting of polyamic acids and polyamic acid esters,
the polyimide precursor contains a structural unit (A) derived from a tetracarboxylic dianhydride and a structural unit (B) derived from a diamine compound, and contains a compound having a nonvolatile crosslinking group at a main chain terminal;
The structural unit (A) is a polyimide precursor that contains a structural unit (A1-2) that does not contain an aromatic ring or in which the ratio of the number of aromatic rings contained in the tetracarboxylic dianhydride to the molecular weight of the tetracarboxylic dianhydride is less than 0.0068.
<3> The polyimide precursor according to <1> or <2>, wherein at least a part of the structural unit (A) has an unsaturated double bond.
<4> The polyimide precursor according to <1> or <3>, wherein a content of the structural unit (A1-1) in the structural unit (A) is 25 mol % or more relative to the structural unit (A).
<5> The polyimide precursor according to <2> or <3>, wherein a content of the structural unit (A) of the structural unit (A1-2) is 25 mol % or more relative to the structural unit (A).
<6> The polyimide precursor according to any one of <1> to <5>, wherein the tetracarboxylic dianhydride includes at least one of compounds represented by the following chemical formulas (A-1) to (A-6):

<7> The polyimide precursor according to any one of <1> to <6>, wherein the structural unit (A) has a structural unit (A2) in which two acid anhydride groups contained in the tetracarboxylic dianhydride are bonded to an aromatic ring.
<8> The polyimide precursor according to any one of <1> to <7>, further comprising a compound having a structural unit represented by the following general formula (6):

(In general formula (6), X represents a tetravalent organic group, and Y represents a divalent organic group. R ⁶ and R ⁷ are each independently a hydrogen atom, a group represented by the following general formula (7), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and at least one of R ⁶ and R ⁷ is a group represented by the following general formula (7). The tetravalent organic group represented by X does not contain an aromatic ring, or if it contains an aromatic ring, the aromatic ring is not bonded to four carbonyl groups.)

(In formula (7), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and q represents an integer of 1 to 10.)
<9> The polyimide precursor according to any one of <1> to <8>, wherein the nonvolatile crosslinking group is derived from at least one compound selected from the group consisting of maleic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, itaconic anhydride, methacrylic anhydride, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 4-ethynylphthalic anhydride, 4-vinylphthalic anhydride, and di-t-butyl dicarbonate.
<10> A resin composition comprising the polyimide precursor according to any one of <1> to <9>.

The present disclosure provides a polyimide precursor that can reduce stress when cured, and a resin composition containing the polyimide precursor.

1A to 1C are diagrams illustrating a manufacturing process for an electronic component according to an embodiment of the present disclosure.

Below, the form for implementing this disclosure will be described in detail. However, this disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless specifically stated otherwise. The same applies to numerical values and their ranges, and they do not limit this disclosure.

In the present disclosure, the numerical range indicated using "to" includes the numerical values before and after "to" as the minimum and maximum values, respectively.
In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
In the present disclosure, each component may contain multiple types of corresponding substances. When multiple types of substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified.
In the present disclosure, the terms "layer" and "film" include cases where the layer or film is formed over the entire area when the area in which the layer or film is present is observed, as well as cases where the layer or film is formed over only a portion of the area.
In the present disclosure, the constituent unit (A) derived from a tetracarboxylic dianhydride may be any constituent unit having a structure formed by ring-opening of a tetracarboxylic dianhydride, and the raw material of the polyimide precursor of the present disclosure is not limited to a tetracarboxylic dianhydride and may be a tetracarboxylic acid or a tetracarboxylic acid derivative.
In the present disclosure, the constituent unit (B) derived from a diamine compound may be any constituent unit having a structure in which one hydrogen atom has been removed from each of two amino groups, and the raw material for the polyimide precursor of the present disclosure is not limited to a diamine compound and may be a derivative of a diamine compound.

<Polyamic Acid>
The polyimide precursor of the present disclosure is at least one type selected from the group consisting of polyamic acids and polyamic acid esters. The polyimide precursor contains a structural unit (A) derived from a tetracarboxylic dianhydride and a structural unit (B) derived from a diamine compound, and contains a compound having a nonvolatile crosslinking group at a main chain terminal, and satisfies the following (1) or (2):
(1) The structural unit (A) contains a structural unit (A1-1) in which the two acid anhydride groups contained in the tetracarboxylic dianhydride are not bonded to an aromatic ring.
(2) The structural unit (A) contains a structural unit (A1-2) that does not contain an aromatic ring, or in which the ratio of the number of aromatic rings contained in the tetracarboxylic dianhydride to the molecular weight of the tetracarboxylic dianhydride is less than 0.0068.

The polyimide precursor of the present disclosure is at least one selected from the group consisting of polyamic acid and polyamic acid ester, and includes a compound having a nonvolatile crosslinking group at the end of the main chain. This makes it possible to reduce stress when the polyimide precursor and a resin composition containing the polyimide precursor are cured.

The compound contained in the polyimide precursor may be one or more polyamic acids, one or more polyamic acid esters, or one or more polyamic acids and one or more polyamic acid esters.

Furthermore, the polyimide precursor of the present disclosure tends to have excellent light transmittance. Therefore, by using a resin composition containing the polyimide precursor, it is possible to form an excellent pattern shape. The reason for this is not clear, but is presumed to be as follows.
First, when the light transmittance of the polyimide precursor and the resin composition containing the polyimide precursor is insufficient, when the photosensitive film containing the polyimide precursor applied to the substrate or the like is subjected to pattern exposure, the bottom of the photosensitive film is difficult to be irradiated with light. Therefore, it is difficult to obtain a patterned cured film having a highly accurate pattern shape corresponding to the pattern exposure. For example, when the photosensitive film is a negative type, the patterned cured film obtained tends to have a reverse taper shape, and when the photosensitive film is a positive type, the patterned cured film obtained tends to have a taper shape.
On the other hand, the polyimide precursor of the present disclosure has a low content of aromatic rings by having the structural unit (A1-1) or the structural unit (A1-2). By using such a polyimide precursor, the light transmittance of the polyimide precursor and the resin composition containing the same is improved. In addition, by improving the light transmittance, when a photosensitive film containing a polyimide precursor applied to a substrate or the like is subjected to pattern exposure, light is irradiated to the bottom of the photosensitive film. This makes it possible to obtain a patterned cured film having a highly accurate pattern shape corresponding to the pattern exposure.
Furthermore, when the structural units (A1-1) and (A1-2) each contain an alicyclic structure, the elasticity of the cured product can be increased, and the durability of the cured product tends to be improved.

Furthermore, the structural unit (A1-1) may contain an aromatic ring that is not bonded to an acid anhydride group, as long as the two acid anhydride groups are not bonded to an aromatic ring. Even if the structural unit (A1-1) contains an aromatic ring, the aromatic ring is not bonded to the two acid anhydride groups, and another functional group, other structure, etc. is bonded to the two acid anhydride groups. This is presumably to reduce the proportion of aromatic rings in the structural unit (A1-1), improving the light transmittance of the polyimide precursor and the resin composition containing it.

The polyimide precursor of the present disclosure may be used in materials that require photosensitivity (e.g., negative or positive photosensitive resin compositions, preferably negative photosensitive resin compositions), or may be used in materials that do not require photosensitivity. When a polyamic acid ester having an unsaturated double bond is used as the polyimide precursor of the present disclosure, the polyimide precursor and a resin composition containing the same may be used in materials that require photosensitivity.

The polyimide precursor of the present disclosure is at least one selected from the group consisting of polyamic acids and polyamic acid esters.
The polyamic acid ester is not particularly limited as long as it is a compound having an ester bond in which at least a portion of the hydrogen atoms of the carboxyl groups in the polyamic acid are substituted with a monovalent organic group. The polyamic acid ester may contain a compound in which at least a portion of the structural unit (A) has an unsaturated double bond.

The structural unit (A) constituting the polyimide precursor has the following structural unit (A1-1) or structural unit (A1-2).
Structural unit (A1-1): A structural unit in which the two acid anhydride groups contained in the tetracarboxylic dianhydride are not bonded to an aromatic ring. Structural unit (A1-2): A structural unit in which the aromatic ring is not contained, or the ratio of the number of aromatic rings contained in the tetracarboxylic dianhydride to the molecular weight of the tetracarboxylic dianhydride is less than 0.0068.

Hereinafter, the ratio of the number of aromatic rings contained in the tetracarboxylic dianhydride to the molecular weight of the tetracarboxylic dianhydride is also referred to as the "aromatic ring content 1."

In the structural units (A1-1) and (A1-2), the two acid anhydride groups contained in the tetracarboxylic dianhydride may be linked by a single bond, or may be linked by a linking group, a composite linking group combining two or more types of linking groups, etc. Examples of the linking group include an alkylene group, a halogenated alkylene group, a phenylene group (however, not bonded to an acid anhydride group), a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-), a silylene bond (-Si(R ^A ) ₂ -; each R ^A independently represents a hydrogen atom, an alkyl group, or a phenyl group), ^a siloxane bond (-O-(Si(R ^B ) ₂ -O-) _n ;
each independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or 2 or more.

From the viewpoint of durability when formed into a cured product, the structural units (A1-1) and (A1-2) preferably contain an alicyclic structure. The structural units may contain one alicyclic structure or two or more alicyclic structures. When the structural units contain two or more alicyclic structures, two alicyclic structures may be bonded at two positions by at least one of a single bond and a linking group to form a five- or six-membered ring containing a linking group between the two alicyclic structures.
The alicyclic ring may have a substituent or may be unsubstituted. Examples of the substituent include an alkyl group, a fluorine atom, a halogenated alkyl group, a hydroxyl group, and an amino group.

Alicyclic structures include the tricyclodecane skeleton, cyclohexane skeleton, cyclopentane skeleton, cyclobutene skeleton, 1,3-adamantane skeleton, hydrogenated bisphenol A skeleton, hydrogenated bisphenol F skeleton, hydrogenated bisphenol S skeleton, and isobornyl skeleton.

In the structural unit (A1-2), the aromatic ring content 1 may be 0.0060 or less, 0.0050 or less, 0.0040 or less, or may be 0, meaning that no aromatic rings are contained.

The structural unit (A1-1) may or may not contain an aromatic ring that is not bonded to the two acid anhydride groups contained in the tetracarboxylic dianhydride. It is preferable that the structural unit (A1-1) does not contain an aromatic ring that is not bonded to the two acid anhydride groups.

When the structural unit (A1-1) contains an aromatic ring, examples of the aromatic ring include a benzene ring, a naphthalene ring, a phenanthrene ring, etc. Of these, a benzene ring is preferred from the viewpoint of improving the light transmittance of the polyimide precursor in the ultraviolet region.
When the structural unit (A1-1) contains an aromatic ring, each aromatic ring may have a substituent or may be unsubstituted. Examples of the substituent on the aromatic ring include an alkyl group, a fluorine atom, a halogenated alkyl group, a hydroxyl group, and an amino group.

When the structural unit (A1-1) contains an aromatic ring, the number of aromatic rings within the structural unit (A1-1) is preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, and particularly preferably 1.
When the structural unit (A1-1) contains two or more aromatic rings, the aromatic rings may be linked by a single bond, or may be linked by a linking group, a composite linking group combining two or more types of linking groups, or the like. Examples of the linking group include an alkylene group, a halogenated alkylene group, a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-), a silylene bond (-Si(R ^A ) ₂ -; R ^A each independently represents a hydrogen atom, an alkyl group, or a phenyl group), a siloxane bond (-O-(Si(R ^B ) ₂ -O-) _n ; R ^B each independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or 2 or more). In addition, two benzene rings may be linked at two points by at least one of a single bond and a linking group to form a five- or six-membered ring containing a linking group between the two aromatic rings.

The tetracarboxylic dianhydride preferably contains at least one of the compounds represented by the following chemical formulas (A-1) to (A-6). The compounds represented by the following chemical formulas (A-1) to (A-6) are preferred examples of the tetracarboxylic dianhydride constituting the structural unit (A1-1) and the tetracarboxylic dianhydride constituting the structural unit (A1-2).

The compound represented by the chemical formula (A-1) and the compound represented by the chemical formula (A-5) are tetracarboxylic dianhydrides containing an aromatic ring that is not bonded to two acid anhydride groups.
The compounds represented by the chemical formulas (A-2) to (A-4) and the compound represented by the chemical formula (A-6) are tetracarboxylic dianhydrides containing no aromatic ring.

The tetracarboxylic dianhydride preferably contains at least one of the compounds represented by the chemical formula (A-2), the compounds represented by the chemical formula (A-4), and the compounds represented by the chemical formula (A-6). By using a polyimide precursor containing a structural unit derived from the compound, it becomes easier to obtain a cured product with low stress.

The structural unit (A) may have a structural unit (A2) in which two acid anhydride groups contained in the tetracarboxylic dianhydride are bonded to an aromatic ring. The inclusion of the structural unit (A2) improves the durability of the cured product. Even when the structural unit (A) contains the structural unit (A2), the proportion of aromatic rings in the entire structural unit (A) is low because the structural unit (A1-1) or (A1-2) is included, and as a result, the polyimide precursor and the resin composition containing it tend to have excellent light transmittance.

The preferred forms of the aromatic ring contained in the structural unit (A2) are the same as the preferred forms of the aromatic ring that can be contained in the structural unit (A1-1).
The number of aromatic rings in the structural unit (A2) is preferably 1 to 4, more preferably 1 to 3, even more preferably 1 or 2, and particularly preferably 1.

In the structural unit (A2), the aromatic ring content 1 may be 0.0045 or more, 0.0050 or more, or 0.0060 or more. The upper limit may be, for example, 0.0100, 0.0080, or 0.0070.

The structural unit (A2) may contain groups represented by the following general formulas (A) to (E):

In general formula (D), A and B each independently represent a single bond, a methylene group, a halogenated methylene group, a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-) or a silylene bond (-Si(R ^A ) ₂ -; each of R ^A independently represents a hydrogen atom, an alkyl group or a phenyl group), and both A and B are not single bonds.

In general formula (E), C represents a single bond, an alkylene group, a halogenated alkylene group, a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-), a silylene bond (-Si(R ^A ) ₂ -; R ^A each independently represents a hydrogen atom, an alkyl group, or a phenyl group), a siloxane bond (-O-(Si(R ^B ) ₂ -O-) _n ; R ^B each independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n is an integer of 1 or 2 or more), or a divalent group comprising at least two of these in combination. C may also have a structure represented by formula (C1) below.

The alkylene group represented by C in general formula (E) is preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably an alkylene group having 1 or 2 carbon atoms.
Specific examples of the alkylene group represented by C in the general formula (E) include linear alkylene groups such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group; a methylmethylene group, a methylethylene group, an ethylmethylene group, a dimethylmethylene group, a 1,1-dimethylethylene group, a 1-methyltrimethylene group, a 2-methyltrimethylene group, an ethylethylene group, a 1-methyltetramethylene group, a 2-methyltetramethylene group, a 1-ethyltrimethylene group, a 2-ethyltrimethylene group, a 1,1-dimethyl branched alkylene groups such as ethyltrimethylene group, 1,2-dimethyltrimethylene group, 2,2-dimethyltrimethylene group, 1-methylpentamethylene group, 2-methylpentamethylene group, 3-methylpentamethylene group, 1-ethyltetramethylene group, 2-ethyltetramethylene group, 1,1-dimethyltetramethylene group, 1,2-dimethyltetramethylene group, 2,2-dimethyltetramethylene group, 1,3-dimethyltetramethylene group, 2,3-dimethyltetramethylene group, and 1,4-dimethyltetramethylene group; and the like. Among these, a methylene group is preferred.

The halogenated alkylene group represented by C in general formula (E) is preferably a halogenated alkylene group having 1 to 10 carbon atoms, more preferably a halogenated alkylene group having 1 to 5 carbon atoms, and even more preferably a halogenated alkylene group having 1 to 3 carbon atoms.
Specific examples of the halogenated alkylene group represented by C in the general formula (E) include alkylene groups in which at least one hydrogen atom contained in the alkylene group represented by C in the above-mentioned general formula (E) is substituted with a halogen atom such as a fluorine atom or a chlorine atom. Among these, a fluoromethylene group, a difluoromethylene group, a hexafluorodimethylmethylene group, etc. are preferred.

The alkyl group represented by R ^A or R ^B contained in the silylene bond or siloxane bond is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and even more preferably an alkyl group having 1 or 2 carbon atoms. Specific examples of the alkyl group represented by R ^A or R ^B include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, and the like.

The combination of A and B in formula (D) is not particularly limited, and a combination of a methylene group and an ether bond, a combination of a methylene group and a sulfide bond, a combination of a carbonyl group and an ether bond, and the like are preferred.
In formula (E), C is preferably a single bond, an ether bond, a carbonyl group, or the like.

The tetracarboxylic dianhydride of the structural unit (A2) may be pyromellitic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 2,3,5,6-pyridine tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic dianhydride, m-terphenyl-3,3',4,4'-tetracarboxylic dianhydride, p-terphenyl-3,3',4,4'-tetracarboxylic dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis (3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis{4'-(2,3-dicarboxyphenoxy)phenyl}propane dianhydride, 2,2-bis{4'-(3,4-dicarboxyphenoxy)phenyl}propane dianhydride, 1,1,1,3,3,3-hexa Examples include fluoro-2,2-bis{4'-(2,3-dicarboxyphenoxy)phenyl}propane dianhydride, 1,1,1,3,3,3-hexafluoro-2,2-bis{4'-(3,4-dicarboxyphenoxy)phenyl}propane dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4'-sulfonyldiphthalic dianhydride, and 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

The content of the structural unit (A1-1) in the structural unit (A) and the content of the structural unit (A1-2) in the structural unit (A) are each independently preferably 25 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more. There is no particular upper limit to the proportions, and the upper limit is not particularly limited, and may be 100 mol%, 80 mol% or less, or 60 mol% or less.

The polyimide precursor contains a structural unit (B) derived from a diamine compound. There are no particular limitations on the structural unit (B) as long as it contains a structure derived from a diamine compound, and it may or may not contain an aromatic ring. From the viewpoint of durability when made into a cured product, it is preferable that the structural unit (B) contains an aromatic ring.

The structural unit (B) preferably contains a structural unit represented by the formula -NH-Y-NH-, where Y is a divalent organic group.
The divalent organic group represented by Y preferably has 6 to 25 carbon atoms, more preferably 6 to 14 carbon atoms, and even more preferably 12 to 14 carbon atoms.
The divalent organic group represented by Y may be a divalent aliphatic group or a divalent aromatic group. From the viewpoint of heat resistance and high elasticity, the divalent organic group represented by Y is preferably a divalent aromatic group.

Specific examples of the divalent aromatic group represented by Y include groups represented by the following general formula (F) and the following general formula (G).

In general formula (F) or general formula (G), each R independently represents an alkyl group, an alkoxy group, a halogenated alkyl group, or a phenyl group, and each n independently represents an integer of 0 to 4.
In general formula (G), D represents a single bond, or an alkylene group, a halogenated alkylene group, a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-), a silylene bond (-Si(R ^A ) ₂ -; R ^A each independently represents a hydrogen atom, an alkyl group, or a phenyl group), a siloxane bond (-O-(Si(R ^B ) ₂ -O-) _n ; R ^B each independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or 2 or more), or a divalent group combining at least two of these. D may also be a structure represented by the above formula (C1). Specific examples of D in general formula (G) are the same as the specific examples of C in general formula (E).
D in formula (G) is preferably a single bond.

The alkyl group represented by R in general formula (F) or general formula (G) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and further preferably an alkyl group having 1 or 2 carbon atoms.
Specific examples of the alkyl group represented by R in general formula (F) or general formula (G) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, and a t-butyl group.

The alkoxy group represented by R in the general formula (F) or the general formula (G) is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 5 carbon atoms, and further preferably an alkoxy group having 1 or 2 carbon atoms.
Specific examples of the alkoxy group represented by R in the general formula (F) or (G) include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, an s-butoxy group, and a t-butoxy group.

The halogenated alkyl group represented by R in the general formula (F) or (G) is preferably a halogenated alkyl group having 1 to 5 carbon atoms, more preferably a halogenated alkyl group having 1 to 3 carbon atoms, and further preferably a halogenated alkyl group having 1 or 2 carbon atoms.
Specific examples of the halogenated alkyl group represented by R in general formula (F) or general formula (G) include alkyl groups in which at least one hydrogen atom contained in the alkyl group represented by R in general formula (F) or general formula (G) is substituted with a halogen atom such as a fluorine atom or a chlorine atom. Among these, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, etc. are preferred.

In general formula (F) or general formula (G), n is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

Specific examples of the divalent aliphatic group represented by Y include linear or branched alkylene groups, cycloalkylene groups, divalent groups having a polyalkylene oxide structure, and divalent groups having a polysiloxane structure.

The linear or branched alkylene group represented by Y is preferably an alkylene group having 1 to 20 carbon atoms, more preferably an alkylene group having 1 to 15 carbon atoms, and even more preferably an alkylene group having 1 to 10 carbon atoms.
Specific examples of the alkylene group represented by Y include a tetramethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, an undecamethylene group, a dodecamethylene group, a 2-methylpentamethylene group, a 2-methylhexamethylene group, a 2-methylheptamethylene group, a 2-methyloctamethylene group, a 2-methylnonamethylene group, and a 2-methyldecamethylene group.

The cycloalkylene group represented by Y is preferably a cycloalkylene group having 3 to 10 carbon atoms, and more preferably a cycloalkylene group having 3 to 6 carbon atoms.
Specific examples of the cycloalkylene group represented by Y include a cyclopropylene group, a cyclohexylene group, and the like.

The unit structure contained in the divalent group having a polyalkylene oxide structure represented by Y is preferably an alkylene oxide structure having 1 to 10 carbon atoms, more preferably an alkylene oxide structure having 1 to 8 carbon atoms, and even more preferably an alkylene oxide structure having 1 to 4 carbon atoms. Of these, the polyalkylene oxide structure is preferably a polyethylene oxide structure or a polypropylene oxide structure. The alkylene group in the alkylene oxide structure may be linear or branched. The unit structure in the polyalkylene oxide structure may be of one type or two or more types.

Examples of the divalent group having a polysiloxane structure represented by Y include divalent groups having a polysiloxane structure in which a silicon atom in the polysiloxane structure is bonded to a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 18 carbon atoms.
Specific examples of the alkyl group having 1 to 20 carbon atoms bonded to a silicon atom in the polysiloxane structure include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-octyl group, a 2-ethylhexyl group, an n-dodecyl group, etc. Among these, a methyl group is preferable.
The aryl group having 6 to 18 carbon atoms bonded to the silicon atom in the polysiloxane structure may be unsubstituted or substituted with a substituent. Specific examples of the substituent when the aryl group has a substituent include a halogen atom, an alkoxy group, and a hydroxy group. Specific examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a naphthyl group, and a benzyl group. Of these, a phenyl group is preferred.
The alkyl group having 1 to 20 carbon atoms or the aryl group having 6 to 18 carbon atoms in the polysiloxane structure may be of one type or of two or more types.
The silicon atom constituting the divalent group having a polysiloxane structure represented by Y may be bonded to the NH group in general formula (6) via an alkylene group such as a methylene group or an ethylene group, or an arylene group such as a phenylene group.

Examples of the diamine compound of the structural unit (B) include 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 1,5-diaminonaphthalene, benzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 2,2'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 2,4'-diaminodiphenyl sulfone, 2,2'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 2,4'-diaminodiphenyl sulfide, 2,2'-diaminodiphenyl sulfide, o-tolidine, o-tolidine sulfone, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis(2,6-di isopropylaniline), 2,4-diaminomesitylene, 1,5-diaminonaphthalene, 4,4'-benzophenonediamine, bis-{4-(4'-aminophenoxy)phenyl}sulfone, 2,2-bis{4-(4'-aminophenoxy)phenyl}propane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis{4-(3'-aminophenoxy)phenyl}sulfone, 2,2-bis(4-aminophenyl)propane, 9,9-bis(4-aminophenyl)fluorene, 1,4-diamino Nobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 2-methyl-1,5-diaminopentane, 2-methyl-1,6-diaminohexane, 2-methyl-1,7-diaminoheptane, 2-methyl-1,8-diaminooctane, 2-methyl-1,9-diaminononane, 2-methyl-1,10-diaminodecane, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, diaminopolysiloxane, and the like.
The diamine compounds may be used alone or in combination of two or more kinds.

The polyimide precursor may contain, for example, a compound having a structural unit represented by the following general formula (6):

In general formula (6), X represents a tetravalent organic group, and Y represents a divalent organic group. R ⁶ and R ⁷ are each independently a hydrogen atom, a group represented by the following general formula (7), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and the tetravalent organic group represented by X does not contain an aromatic ring, or if it contains an aromatic ring, the aromatic ring is not bonded to four carbonyl groups. When the compound having a constitutional unit represented by general formula (6) is a polyamic acid ester having an unsaturated double bond, it is preferable that at least one of R ⁶ and R ⁷ is a group represented by the following general formula (7).

In formula (7), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms; q represents an integer of 1 to 10.

The number of carbon atoms in the aliphatic hydrocarbon group represented by ^R6 and ^R7 in general formula (6) is 1 to 4, and preferably 1 or 2. Specific examples of the aliphatic hydrocarbon group represented by ^R6 and ^R7 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and the like.

In the general formula (6), at least one of R ⁶ and R ⁷ may be a group represented by the general formula (7), or both of R ⁶ and R ⁷ may be a group represented by the general formula (7).

The carbon number of the aliphatic hydrocarbon group represented by R ⁸ to R ¹⁰ in general formula (7) is 1 to 3, and preferably 1 or 2. Specific examples of the aliphatic hydrocarbon group represented by R ⁸ to R ¹⁰ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, etc., and a methyl group is preferred.

As a combination of R ⁸ to R ¹⁰ in the general formula (7), a combination in which R ⁸ and R ⁹ are hydrogen atoms and R ¹⁰ is a hydrogen atom or a methyl group is preferred.

In general formula (7), q is preferably an integer from 1 to 10, more preferably an integer from 2 to 5, and even more preferably 2 or 3.

In formula (6), Y has the same meaning as Y explained in relation to the structural unit (B).
X in the general formula (6) may be any of the linking groups and composite linking groups described in relation to the structural units (A1-1) and (A1-2).

In general formula (6), the tetravalent organic group represented by X preferably has 4 to 25 carbon atoms, more preferably 4 to 13 carbon atoms, and even more preferably 6 to 12 carbon atoms.

The tetravalent organic group represented by X may contain an aromatic ring. If X contains an aromatic ring, the aromatic ring is not bonded to four carbonyl groups.

In general formula (6), specific examples of X include the groups shown below, but the present disclosure is not limited to the specific examples below.

When X corresponds to a residue derived from a tetracarboxylic dianhydride, specific examples of the tetracarboxylic dianhydride that is the source of the residue include the tetracarboxylic dianhydrides exemplified for the structural units (A1-1) and (A1-2).

In formula (6), it is preferred that the --COOR ⁶ group and the --CONH-- group are in the ortho position relative to each other, and the --COOR ⁷ group and the --CO-- group are in the ortho position relative to each other.

The compound contained in the polyimide precursor may further have a structural unit represented by the following general formula (6-1) in addition to the structural unit represented by the general formula (6).

In the general formula (6-1), X ¹ represents a tetravalent organic group, and Y represents a divalent organic group. R ⁶ and R ⁷ are each independently a hydrogen atom, a group represented by the following general formula (7), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and at least one of R ⁶ and R ⁷ is a group represented by the following general formula (7), and the tetravalent organic group represented by X ¹ contains an aromatic ring. It is preferable that the four carbonyl groups in the general formula (6-1) are bonded to the aromatic ring contained in X ¹ , and it is more preferable that the two carbonyl groups in the general formula (6-1) are bonded to one aromatic ring (first aromatic ring) contained in X ¹ , and the remaining two carbonyl groups are bonded to another aromatic ring (second aromatic ring) contained in X ¹ .

Y, R ⁶ and R ⁷ in formula (6-1) have the same meanings as Y, R ⁶ and R ⁷ in formula (6), respectively.

Specific examples of ^X1 in the general formula (6-1) include the general formulae (A) to (E) described in relation to the structural unit (A2).

When X corresponds to a residue derived from a tetracarboxylic dianhydride, specific examples of the tetracarboxylic dianhydride that is the source of the residue include the tetracarboxylic dianhydrides described in relation to the structural unit (A2).

The polyimide precursor may have other structural units in addition to general formula (6) and general formula (6-1).

The polyimide precursor may contain a structural unit represented by general formula (6) (hereinafter also referred to as structural unit 1) and a structural unit represented by general formula (6-1) (hereinafter also referred to as structural unit 2). Furthermore, in the polyimide precursor, the ratio of structural unit 1 to the total of structural units 1 and 2 is preferably 25 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more. There is no particular upper limit to this ratio, and the upper limit is not particularly limited, and it may be 100 mol%, 80 mol% or less, or 60 mol% or less.

The polyimide precursor includes a compound that contains structural unit (A) and structural unit (B) and has a nonvolatile crosslinking group at the end of the main chain.

The non-volatile crosslinking group is a functional group capable of crosslinking reaction that is located at the end of the main chain of the compound contained in the polyimide precursor and does not volatilize due to heating, drying, etc. The non-volatile crosslinking group may be a functional group that contains an unsaturated double bond.

Examples of compounds used when forming a nonvolatile crosslinking group at the main chain end of a compound contained in a polyimide precursor (hereinafter also referred to as a nonvolatile crosslinking group forming compound) include maleic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, itaconic anhydride, methacrylic anhydride, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 4-ethynylphthalic anhydride, 4-vinylphthalic anhydride, di-t-butyl dicarbonate, etc. These compounds react with amino groups derived from a diamine compound to obtain a compound having a nonvolatile crosslinking group at the main chain end.
As the non-volatile crosslinking group-forming compound, from the viewpoint of reducing stress in the cured product when the polyimide precursor or a resin composition containing the polyimide precursor is cured at high temperature (e.g., 350°C), maleic anhydride and 5-norbornene-2,3-dicarboxylic acid anhydride are preferred, and from the viewpoint of reducing stress in the cured product when the cured product is produced using a photopolymerization initiator in particular, maleic anhydride is more preferred.
The non-volatile crosslinking group-forming compounds may be used alone or in combination of two or more.

The polyimide precursor may be synthesized using a tetracarboxylic dianhydride, a diamine compound, and a non-volatile cross-linking group-forming compound, or may be synthesized using a tetracarboxylic dianhydride that is at least one of the compounds represented by chemical formulas (A-1) to (A-6), a tetracarboxylic dianhydride of the aforementioned structural unit (A2), a diamine compound, and a non-volatile cross-linking group-forming compound. Note that the polyimide precursor may be synthesized using a tetracarboxylic acid instead of a tetracarboxylic dianhydride.

The polyamic acid can be obtained, for example, by reacting a tetracarboxylic dianhydride, a diamine compound, and a non-volatile cross-linking group-forming compound in an organic solvent.
The polyamic acid ester can be obtained, for example, by the following method (1) or (2).
(1) A tetracarboxylic dianhydride is reacted with a compound represented by R—OH in an organic solvent to form a diester derivative, and then the diester derivative is reacted with a diamine compound and a non-volatile crosslinking group-forming compound.
(2) A tetracarboxylic dianhydride, a diamine compound, and a non-volatile cross-linking group-forming compound are reacted in an organic solvent to obtain a polyamic acid, and a compound represented by R-OH is added to the organic solvent containing the polyamic acid, and an ester group is introduced by reacting them in the organic solvent.
R in the compound represented by R-OH represents a group represented by general formula (7) or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and specific and preferred examples are the same as those of ^R6 and ^R7 in general formula (6).

Also, a polyamic acid ester can be obtained by reacting a compound represented by R-OH with a tetracarboxylic dianhydride to form a diester derivative, then reacting the diester with a chlorinating agent such as thionyl chloride to convert it to an acid chloride, and then reacting a diamine compound, the acid chloride, and a non-volatile crosslinking group-forming compound.
Furthermore, the polyamic acid ester can be obtained by reacting a compound represented by R-OH with a tetracarboxylic dianhydride to form a diester derivative, and then reacting the diamine compound, the diester derivative, and a non-volatile crosslinking group-forming compound in the presence of a carbodiimide compound.
Furthermore, the polyamic acid ester can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound to form a polyamic acid, isoimidizing the polyamic acid in the presence of trifluoroacetic anhydride, and then reacting the compound represented by R-OH and a non-volatile crosslinking group forming compound. In this case, the compound represented by R-OH may be reacted in advance with a part of the tetracarboxylic dianhydride, and the partially esterified tetracarboxylic dianhydride may be reacted with the diamine compound to form a polyamic acid.

Compounds represented by R-OH that are used in the synthesis of polyamic acid esters include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, etc.

In the synthesis of the polyimide precursor, the molar ratio of the amount of tetracarboxylic dianhydride used to the amount of non-volatile cross-linking group-forming compound used (tetracarboxylic dianhydride: non-volatile cross-linking group-forming compound) may be 0.7:0.3 to 0.95:0.05, 0.75:0.25 to 0.95:0.05, or 0.8:0.2 to 0.9:0.1.

In the synthesis of the polyimide precursor, the molar ratio of the total amount of the tetracarboxylic dianhydride and the non-volatile cross-linking group-forming compound used to the amount of the diamine compound used (tetracarboxylic dianhydride and the non-volatile cross-linking group-forming compound:diamine compound) may be 1.0:0.75 to 1.0:1.0, 1.0:0.8 to 1.0:0.95, or 1.0:0.85 to 1:0.95.

The tetracarboxylic dianhydride, diamine compound, non-volatile crosslinking group-forming compound, and compound represented by R-OH may each be used alone or in combination of two or more.

The molecular weight of the polyimide precursor is not particularly limited, and may be, for example, 10,000 to 200,000, 20,000 to 150,000, or 30,000 to 100,000 in weight average molecular weight.
The weight average molecular weight can be measured, for example, by gel permeation chromatography, and can be calculated using a standard polystyrene calibration curve.

From the viewpoint of obtaining a cured product with low stress, the weight average molecular weight of the polyimide precursor may be 10,000 or more, 20,000 or more, 30,000 or more, or 40,000 or more.
The weight average molecular weight of the polyimide precursor may be 100,000 or less, 60,000 or less, 50,000 or less, or 30,000 or less, from the viewpoints of developability and pattern resolution in a lithography process.

<Resin Composition>
The resin composition of the present disclosure includes the polyimide precursor of the present disclosure. The resin composition may include other components other than the polyimide precursor of the present disclosure. Examples of the other components include resin components other than the polyimide precursor of the present disclosure, polymerizable monomers, photopolymerization initiators, thermal polymerization initiators, solvents, sensitizers, stabilizers, coupling agents, surfactants, leveling agents, and rust inhibitors.

Polymerizable monomers include polymerizable monomers having a (meth)acrylic group, styrene, divinylbenzene, 4-vinyltoluene, 4-vinylpyridine, N-vinylpyrrolidone, methylenebisacrylamide, N,N-dimethylacrylamide, and N-methylolacrylamide.

Examples of the photopolymerization initiator include benzophenone derivatives, acetophenone derivatives, thioxanthone derivatives, benzyl derivatives, benzoin derivatives, oxime derivatives, N-arylglycines; peroxides; aromatic biimidazoles; acylphosphine oxide derivatives, Irgacure OXE03 (manufactured by BASF Corporation), and Irgacure OXE04 (manufactured by BASF Corporation).
Among these, oxime derivatives are preferred from the viewpoint of not containing a metal element, having high reactivity and high sensitivity. For example, examples of the oxime derivatives that can be used include 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-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, and 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(o-benzoyloxime) (e.g., Irgacure OXE01).

Solvents include N-methyl-2-pyrrolidone, γ-butyrolactone, ethyl lactate, propylene glycol monomethyl ether acetate, benzyl acetate, n-butyl acetate, ethoxyethyl propionate, methyl 3-methoxypropionate, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphorylamide, tetramethylene sulfone, cyclohexanone, cyclopentanone, diethyl ketone, diisobutyl ketone, methyl amyl ketone, N-dimethylmorpholine, 3-methoxy-N,N-dimethylpropanamide, etc., and there are no particular limitations as long as they can sufficiently dissolve each component contained in the resin composition.

The resin composition of the present disclosure may be a photosensitive resin composition, or may be a thermosetting resin composition that is cured by heating.
The resin composition of the present disclosure may be, for example, a composition that can provide a cured product by irradiation with light, heating, etc. When the resin composition is a photosensitive resin composition, a patterned cured product may be formed using the photosensitive resin composition.

<Cured Product>
The cured product obtained from the resin composition of the present disclosure can be used as an interlayer insulating film, a cover coat layer, or a surface protective film. Furthermore, the cured product can be used as a passivation film, a buffer coat film, etc.
Using one or more selected from the group consisting of the above passivation films, buffer coat films, interlayer insulating films, cover coat layers, and surface protection films, etc., highly reliable electronic components such as semiconductor devices, multilayer wiring boards, various electronic devices, and stacked devices (multi-die fan-out wafer level packages, etc.) can be manufactured.

<Electronic Components>
The electronic component of the present disclosure includes a cured product obtained by curing the resin composition of the present disclosure described above.

An example of a manufacturing process for the electronic component of the present disclosure will be described with reference to the drawings.
FIG. 1 is a manufacturing process diagram of an electronic component having a multilayer wiring structure according to an embodiment of the present disclosure.
1, a semiconductor substrate 1 such as a Si substrate having circuit elements is covered with a protective film 2 such as a silicon oxide film except for a predetermined portion of the circuit elements, and a first conductor layer 3 is formed on the exposed circuit elements. Then, an interlayer insulating film 4 is formed on the semiconductor substrate 1.

Next, a photosensitive resin layer 5, such as a chlorinated rubber or phenol novolac type, is formed on the interlayer insulating film 4, and windows 6A are provided using known photoetching techniques to expose predetermined portions of the interlayer insulating film 4.

The interlayer insulating film 4 from which the window 6A is exposed is selectively etched to provide a window 6B.
Next, the photosensitive resin layer 5 is removed using an etching solution that corrodes the photosensitive resin layer 5 without corroding the first conductor layer 3 exposed through the windows 6B.

Further, a second conductor layer 7 is formed by using a known photolithography technique, and is electrically connected to the first conductor layer 3 .
When forming a multi-layer wiring structure having three or more layers, the above steps can be repeated to form each layer.

Next, the resin composition of the present disclosure is used to open windows 6C by pattern exposure to form a surface protective film 8. The surface protective film 8 protects the second conductor layer 7 from external stress, α-rays, and the like, and the obtained electronic component has excellent reliability.
In the above example, the interlayer insulating film 4 can also be formed using the resin composition of the present disclosure.

The present disclosure will be explained in more detail below based on examples and comparative examples. Note that the present disclosure is not limited to the following examples.

(Synthesis of Polyamic Acid 1)
As raw materials, 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA, molecular weight 294.22) dried in a dryer at 160°C for 24 hours, a compound represented by chemical formula (A-2) (CpODA, molecular weight 384.38) dried in a dryer at 160°C for 24 hours, maleic anhydride (MA, molecular weight 98.06), and p-phenylenediamine (PPD, molecular weight 108.14) were prepared.
In a nitrogen-purged 0.1-liter round-bottom flask, 2.356 g of sBPDA, 3.076 g of CpODA, 0.393 g of MA, and 0.018 g of benzoquinone (BQ) were added to 32.67 g of 3-methoxy-N,N-dimethylpropanamide ("KJCMPA-100" (KJ Chemicals Corporation)), and the mixture was stirred at 30° C. to obtain a sBPDA/CpODA/MA solution.
A p-phenylenediamine (PPD) solution was prepared by mixing 1.947 g of PPD and 9.998 g of KJCMPA-100.
The prepared PPD solution and 5.001 g of KJCMPA-100 were added dropwise to the sBPDA/CpODA/MA solution and stirred at 30° C. As a result, polyamic acid solution 1 was obtained, which contains a structural unit (A) derived from sBPDA and CpODA and a structural unit (B) derived from PPD, and contains polyamic acid 1 having a nonvolatile crosslinking group derived from MA at the main chain end.
On a raw material basis, the molar ratio of sBPDA, CpODA, MA and PPD was sBPDA:CpODA:MA:PPD=0.4:0.4:0.2:0.9.

This polyamic acid 1 solution was dropped into distilled water, and the precipitate was collected by filtration and dried under reduced pressure to obtain polyamic acid 1. The weight average molecular weight of polyamic acid 1 calculated in terms of standard polystyrene was 15,900.

In this example, the weight average molecular weight of the polyamic acid was determined using gel permeation chromatography (GPC) in terms of standard polystyrene. Specifically, a solution in which 0.5 mg of polyamic acid was dissolved in 1 mL of a solvent [tetrahydrofuran (THF)/dimethylformamide (DMF) = 1/1 (volume ratio)] was used, and the measurement was performed under the following conditions.

-Measurement condition-
Measuring device: Shimadzu Corporation SPD-M20A
Pump: Shimadzu Corporation LC-20AD
Column oven: Shimadzu Corporation: CTO-20A
Measurement conditions: Column Gelpack GL-S300MDT-5 x 2 Eluent: THF/DMF = 1/1 (volume ratio)
LiBr (0.03 mol/L), _H3PO4 ( _0.06 mol/L)
Flow rate: 1.0 mL/min, detector: UV 270 nm, column temperature: 40° C.
Standard polystyrene: Tosoh TSKgel standard polystyrene Type F-1, F-4, F-20, F-80, A-2500 to create a calibration curve

The viscosity of the polyamic acid 1 solution was measured at 25°C using an E-type viscometer. The results are shown in Table 1.

(Synthesis of polyamic acids 2 to 6)
In the synthesis of polyamic acid 1, the molar ratios of sBPDA, CpODA, MA and PPD on a raw material basis were changed as shown in Table 1, and the amount of the solvent KJCMPA-100 was appropriately changed, but the same procedure was followed to obtain polyamic acid solutions 2 to 6 containing polyamic acids 2 to 6. Furthermore, polyamic acids 2 to 6 were obtained from polyamic acid solutions 2 to 6 in the same manner as above.
The weight average molecular weights of polyamic acids 2 to 6, calculated in terms of standard polystyrene, and the viscosities of polyamic acid solutions 2 to 6 were determined. The results are shown in Table 1.

(Synthesis of polyamic acid 7)
In the synthesis of polyamic acid 1, MA was not used, the molar ratio of sBPDA, sBPDA, MA and PPD on a raw material basis was changed to sBPDA:CpODA:MA:PPD=0.5:0.5:0:0.9, and the amount of the solvent KJCMPA-100 was appropriately changed, but otherwise the same procedure was followed as in the synthesis of polyamic acid 1 to obtain polyamic acid solution 7 containing polyamic acid 7. Furthermore, polyamic acid 7 was obtained from polyamic acid solution 7 in the same manner as above.
The weight average molecular weight of polyamic acid 7, calculated in terms of standard polystyrene, and the viscosity of polyamic acid solution 7 were determined. The results are shown in Table 1.

(Synthesis of polyamic acid 8)
As raw materials, 3,3',4,4'-biphenyltetracarboxylic dianhydride (sBPDA, molecular weight 294.22) dried in a dryer at 160°C for 24 hours, a compound represented by chemical formula (A-2) (CpODA, molecular weight 384.38) dried in a dryer at 160°C for 24 hours, 5-norbornene-2,3-dicarboxylic anhydride (NA, molecular weight 164.16), and p-phenylenediamine (PPD, molecular weight 108.14) were prepared.
In a nitrogen-purged 0.1-liter round-bottom flask, 2.354 g of sBPDA, 3.076 g of CpODA, 0.657 g of MA, and 0.0175 g of benzoquinone (BQ) were added to 38.55 g of KJCMPA-100, and the mixture was stirred at 30° C. to obtain a sBPDA/CpODA/NA solution.
A p-phenylenediamine (PPD) solution was prepared by mixing 1.948 g of PPD and 10.001 g of KJCMPA-100.
The prepared PPD solution and 5.001 g of KJCMPA-100 were added dropwise to the sBPDA/CpODA/NA solution and stirred at 30° C. As a result, polyamic acid solution 8 was obtained, which contains a structural unit (A) derived from sBPDA and CpODA and a structural unit (B) derived from PPD, and which contains a polyamic acid 8 having a nonvolatile crosslinking group derived from NA at the main chain end. Polyamic acid 8 was obtained from polyamic acid solution 8 in the same manner as above.
On a raw material basis, the molar ratio of sBPDA, CpODA, NA and PPD was sBPDA:CpODA:NA:PPD=0.4:0.4:0.2:0.9.
The weight average molecular weight of polyamic acid 8 was calculated in terms of standard polystyrene, and the viscosity of polyamic acid solution 8 was determined. The results are shown in Table 1.

(Synthesis of polyamic acids 9 to 13)
In the synthesis of polyamic acid 8, the molar ratios of sBPDA, CpODA, NA, and PPD on a raw material basis were changed as shown in Table 1, and the amount of the solvent KJCMPA-100 was appropriately changed, and polyamic acid solutions 9 to 13 containing polyamic acids 9 to 13 were obtained in the same manner as in the synthesis of polyamic acid 8. Furthermore, polyamic acids 9 to 13 were obtained from polyamic acid solutions 9 to 13 in the same manner as above.
The weight average molecular weight of each of the polyamic acids 9 to 13 was calculated based on standard polystyrene and the viscosity of each of the polyamic acid solutions 9 to 13 was determined. The results are shown in Table 1.

(Stress measurement 1)
The aforementioned polyamic acid solutions 1 to 14 were applied onto a 6-inch silicon wafer by spin coating at 1000 rpm (revolutions per minute), and heated on a hot plate at 120° C. for 200 seconds to volatilize the solvent and obtain a coating film having a thickness of about 10 μm after curing. This was then heated and cured at 350° C. for 1 hour in a nitrogen atmosphere using a vertical diffusion furnace manufactured by Koyo Lindberg, to obtain a polyimide film (cured film). The residual stress of the cured polyimide film was measured at room temperature using a thin film stress measurement device FLX-2320 manufactured by KLATencor.
The results are shown in Table 2.

(Stress measurement 2)
The aforementioned polyamic acid solutions 1 to 13 were applied onto a 6-inch silicon wafer by spin coating at 1000 rpm (revolutions per minute), and heated on a hot plate at 120° C. for 200 seconds to volatilize the solvent and obtain a coating film having a thickness of about 10 μm after curing. This was then heated and cured for 2 hours at 280° C., 250° C. or 200° C. in a nitrogen atmosphere using a vertical diffusion furnace manufactured by Koyo Lindberg, to obtain a polyimide film (cured film). The residual stress of the cured polyimide film was measured in the same manner as in Stress Measurement 1.
The results are shown in Table 2.

(Preparation of Resin Composition)
Resin compositions 1 to 13 were prepared using the above-mentioned polyamic acid solutions 1 to 13, respectively. Specifically, Irgacure OXE-01 (1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime)), a photopolymerization initiator having a solid content concentration of 1.5% by mass, was added to the polyamic acid solutions 1 to 13 to prepare the resin compositions 1 to 13.

(Stress measurement 3)
The above-mentioned resin compositions 1 to 13 were applied onto a 6-inch silicon wafer by spin coating at 1000 rpm (revolutions per minute), and heated on a hot plate at 120°C for 200 seconds to volatilize the solvent and obtain a coating film having a thickness of about 10 μm after curing. The coating film was irradiated with broadband light at 400 mJ/ ^cm2 . The coating film after light irradiation was heated and cured in a nitrogen atmosphere at 350°C for 1 hour or at 250°C for 2 hours using a vertical diffusion furnace manufactured by Koyo Lindberg, to obtain a polyimide film (cured film). The residual stress of the cured polyimide film was measured in the same manner as in Stress Measurement 1.
The results are shown in Table 3.

As shown in Table 2, polyamic acid solutions 1 to 6 and 8 to 13, which contain polyamic acid having MA-derived or NA-derived nonvolatile crosslinking groups at the ends of the main chain, had reduced stress in the polyimide film after curing at 350°C compared to polyamic acid solution 7, which contains polyamic acid that does not contain nonvolatile crosslinking groups at the ends of the main chain.

As shown in Table 3, in resin compositions 1 to 6 containing polyamic acid having MA-derived nonvolatile crosslinking groups at the ends of the main chain, the stress of the polyimide film after curing at 350°C and the stress of the polyimide film after curing at 250°C were reduced compared to resin composition 7 containing polyamic acid not having a nonvolatile crosslinking group at the ends of the main chain. The reason for this is presumed to be that the molecular weight of the polyimide during curing is efficiently increased by using a polyamic acid having a nonvolatile crosslinking group in combination with a polymerization initiator, resulting in a reduction in the stress of the cured film.

The disclosure of Japanese Patent Application No. 2022-176685, filed on November 2, 2022, is incorporated herein by reference in its entirety.
All publications, patent applications, and standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Reference Signs List 1 Semiconductor substrate 2 Protective film 3 First conductor layer 4 Interlayer insulating film 5 Photosensitive resin layer 6A, 6B, 6C Window 7 Second conductor layer 8 Surface protective film

Claims

A polyimide precursor which is at least one selected from the group consisting of polyamic acids and polyamic acid esters,
the polyimide precursor contains a structural unit (A) derived from a tetracarboxylic dianhydride and a structural unit (B) derived from a diamine compound, and contains a compound having a nonvolatile crosslinking group at a main chain terminal;
The structural unit (A) is a polyimide precursor that includes a structural unit (A1-1) in which the two acid anhydride groups contained in the tetracarboxylic dianhydride are not bonded to an aromatic ring.
A polyimide precursor which is at least one selected from the group consisting of polyamic acids and polyamic acid esters,
the polyimide precursor contains a structural unit (A) derived from a tetracarboxylic dianhydride and a structural unit (B) derived from a diamine compound, and contains a compound having a nonvolatile crosslinking group at a main chain terminal;
The structural unit (A) is a polyimide precursor that contains a structural unit (A1-2) that does not contain an aromatic ring or in which the ratio of the number of aromatic rings contained in the tetracarboxylic dianhydride to the molecular weight of the tetracarboxylic dianhydride is less than 0.0068.
The polyimide precursor of claim 1 or 2, wherein at least a portion of the structural unit (A) has an unsaturated double bond.
The polyimide precursor according to claim 1, wherein the content of the structural unit (A1-1) in the structural unit (A) is 25 mol % or more relative to the structural unit (A).
The polyimide precursor according to claim 2, wherein the content of the structural unit (A1-2) in the structural unit (A) is 25 mol % or more relative to the structural unit (A).
The polyimide precursor according to claim 1 or 2, wherein the tetracarboxylic dianhydride comprises at least one of compounds represented by the following chemical formulas (A-1) to (A-6):
The polyimide precursor according to claim 1 or 2, wherein the structural unit (A) has a structural unit (A2) in which two acid anhydride groups contained in the tetracarboxylic dianhydride are bonded to an aromatic ring.
The polyimide precursor according to claim 1 or 2, comprising a compound having a structural unit represented by the following general formula (6):

(In general formula (6), X represents a tetravalent organic group, and Y represents a divalent organic group. R 6 and R 7 are each independently a hydrogen atom, a group represented by the following general formula (7), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and at least one of R 6 and R 7 is a group represented by the following general formula (7). The tetravalent organic group represented by X does not contain an aromatic ring, or if it contains an aromatic ring, the aromatic ring is not bonded to four carbonyl groups.)

(In formula (7), R 8 to R 10 each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and q represents an integer of 1 to 10.)
The polyimide precursor according to claim 1 or 2, wherein the non-volatile crosslinking group is derived from at least one compound selected from the group consisting of maleic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, itaconic anhydride, methacrylic anhydride, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 4-ethynylphthalic anhydride, 4-vinylphthalic anhydride, and di-t-butyl dicarbonate.
A resin composition containing the polyimide precursor according to claim 1 or 2.