WO2025013140A1 - Polyimide-based resin precursor, photosensitive resin composition, method for producing resin film, and amic acid ester compound - Google Patents

Abstract

The polyimide-based resin precursor contains at least one of a constituent unit represented by formula (A1) or a constituent unit represented by formula (A2). At least one of R2 or R3 is an optionally substituted aromatic group, at least one of R2 or R3 is a group containing a photopolymerizable group, and R4 represents an aromatic group substituted with a group containing a photopolymerizable group.

Description

Polyimide resin precursor, photosensitive resin composition, method for producing resin film, and amic acid ester compound

The present disclosure relates to a polyimide resin precursor, a photosensitive resin composition, a method for producing a resin film, and an amic acid ester compound.

The insulating resin layer that constitutes the semiconductor device may be formed from a resin composition that contains a polyimide precursor that forms polyimide when heated (for example, Patent Document 1).

JP 2021-196482 A

One aspect of the present disclosure relates to a polyimide resin precursor that can be formed by heating at low temperature into a polyimide resin that contains a structural unit having an imide group.

で表される構成単位、又は、式（Ａ２）：

で表される構成単位のうち少なくとも一方を含み、
　式（Ａ１）中、Ｘ^１が４価の有機基を示し、Ｒ^１が２価の有機基を示し、Ｒ^２及びＲ^３がそれぞれ独立に１価の有機基を示し、Ｒ^２又はＲ^３のうち少なくとも一方が、置換されていてもよい芳香族基であり、且つ、Ｒ^２又はＲ^３のうち少なくとも一方が、光重合性基を含む基であり、
　式（Ａ２）中、Ｘ^２が３価の有機基を示し、Ｒ^１が２価の有機基を示し、Ｒ^４が光重合性基を含む基で置換された芳香族基を示す、
ポリイミド系樹脂前駆体。
［２］
　［１］に記載のポリイミド系樹脂前駆体を含む、感光性樹脂組成物。
［３］
　［１］に記載のポリイミド系樹脂前駆体を含む感光性樹脂膜の一部に活性光線を照射することと、
　前記感光性樹脂膜の一部を除去することにより、パターン化された膜を形成することと、
　前記パターン化された膜を加熱することにより、イミド基を有する構成単位を含むイミド系樹脂を含む樹脂膜を形成することと、
を含む、樹脂膜を製造する方法。
［４］
　前記パターン化された膜を２００℃以下に加熱することにより、前記樹脂膜が形成される、［３］に記載の方法。
［５］
　下記式（Ｉ）：

で表され、Ｒ^１５が水素原子又はメチル基を示し、Ｒ^１６がアルキル基、又はアリール基を示し、Ｘ^３がメタンジイル基、エタン－１，２－ジイル基、エテン－１，２－ジイル基、又は１，２－フェニレン基を示す、アミド酸エステル化合物。 The present disclosure includes the following.
[1]
The following formula (A1):

Or a structural unit represented by formula (A2):

The structural unit includes at least one of the structural units represented by
In formula (A1), ^X1 represents a tetravalent organic group, ^R1 represents a divalent organic group, ^R2 and ^R3 each independently represent a monovalent organic group, at least one of ^R2 and ^R3 is an aromatic group which may be substituted, and at least one of ^R2 and ^R3 is a group containing a photopolymerizable group;
In formula (A2), ^X2 represents a trivalent organic group, ^R1 represents a divalent organic group, and ^R4 represents an aromatic group substituted with a group containing a photopolymerizable group.
Polyimide resin precursor.
[2]
A photosensitive resin composition comprising the polyimide resin precursor according to [1].
[3]
Irradiating a part of a photosensitive resin film containing the polyimide-based resin precursor according to [1] with actinic rays;
removing a portion of the photosensitive resin film to form a patterned film;
heating the patterned film to form a resin film containing an imide-based resin that includes a structural unit having an imide group;
A method for producing a resin film comprising the steps of:
[4]
The method according to [3], wherein the resin film is formed by heating the patterned film to 200° C. or less.
[5]
The following formula (I):

wherein R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents an alkyl group or an aryl group, and X ³ represents a methanediyl group, an ethane-1,2-diyl group, an ethene-1,2-diyl group, or a 1,2-phenylene group.

A polyimide resin precursor is provided that can be heated at low temperatures to form a polyimide resin that contains a structural unit having an imide group. By heating a resin film that contains the polyimide resin precursor at low temperatures, a resin film with little coloring can be formed.

1A to 1C are process diagrams showing an example of a method for producing a resin film. 1 is a DSC curve of an amic acid ester compound. 1 is a ¹ H NMR spectrum of an amic acid ester compound. 1 is a ¹ H NMR spectrum of an amic acid ester compound.

The present invention is not limited to the following examples.

An example of a polyimide resin precursor according to the present disclosure is a polymer containing at least one of a structural unit represented by the following formula (A1) and a structural unit represented by the following formula (A2).

In formula (A1), X ¹ represents a tetravalent organic group, R ¹ represents a divalent organic group, and R ² and R ³ each independently represent a monovalent organic group. At least one of R ² or R ³ is an aromatic group which may be substituted. Also, at least one of R ² or R 3 is a group containing a photopolymerizable group. One or both of R ² and R ³ may be an aromatic group substituted with a group containing a photopolymerizable group. Alternatively, one of R ² or R ³ may be an aromatic group not substituted with a group containing a photopolymerizable group, and the remaining ^{one of R 2 or} R ³ may be a group containing a photopolymerizable group other than an aromatic group. In the multiple structural units represented by formula (A1) contained in the polyimide resin precursor, the combinations of R ¹ , R ² , R ³ and X ¹ may be the same or different from each other.

In formula (A2), ^X2 represents a trivalent organic group, ^R1 represents a divalent organic group, and ^R4 represents an aromatic group substituted with a group containing a photopolymerizable group. In the multiple structural units represented by formula (A2) contained in the polyimide resin precursor, the combinations of ^R1 , ^R4, and ^X2 may be the same or different from each other.

Imidization proceeds by reaction between the amide group and the carboxylic acid ester group in the structural unit represented by formula (A1) or (A2), thereby forming a polyimide resin. A polyimide resin formed from a polyimide resin precursor mainly composed of structural units represented by formula (A1) is sometimes called a polyimide resin. A polyimide resin formed from a polyamide resin precursor mainly composed of structural units represented by formula (A2) is sometimes called a polyamideimide resin.

The constitutional unit represented by formula (A1) can form, for example, a constitutional unit represented by the following formula (B1) by eliminating an alcohol compound (R ² -OH, R ³ -OH) through imidization. The constitutional unit represented by formula (A2) can form, for example, a constitutional unit represented by the following formula (B2) by eliminating an alcohol compound (R ⁴ -OH) through imidization. The polyimide resin formed by imidization may contain at least one of the constitutional unit represented by formula (B1) or the constitutional unit represented by formula (B2).

When at least one of ^R2 and ^R3 is an aromatic group which may be substituted, and ^R4 is an aromatic group which may be substituted, an aromatic alcohol compound is eliminated by imidization. The imidization reaction in which an aromatic alcohol compound having a phenolic hydroxyl group with a relatively high acidity is eliminated proceeds efficiently at a relatively low temperature, as confirmed in the verification test described below. Therefore, the polyimide resin precursor according to the present disclosure can form a polyimide resin containing a structural unit having an imide group by heating at a lower temperature.

The molecular weight of the aromatic alcohol compound eliminated by imidization may be from 50 to 100,000. At least one of ^R2 and ^R3 , and ^R4 may be a residue of an aromatic alcohol compound having a molecular weight within these ranges.

Examples of aromatic groups as R ² , R ³ or R ⁴ include monocyclic aromatic groups such as phenyl groups, and polycyclic aromatic groups such as naphthyl groups. The aromatic groups as R ² , R ³ or R ⁴ may be substituted. The aromatic groups as R ² , R ³ or R ⁴ may be substituted with a group containing a photopolymerizable group (for example, a group represented by formula (10) described below), or may be substituted with a substituent that does not contain a photopolymerizable group. Examples of substituents that do not contain a photopolymerizable group include an alkyl group, a halogeno group, a halogenated alkyl group, an aryl group (for example, a phenyl group), a halogenated aryl group, an alkylaryl group, a halogenated alkylaryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylcarbonyloxy group and an arylcarbonyloxy group.

The photopolymerizable group contained in R ² , R ³ or R ⁴ is a functional group having a double bond, and may be, for example, a methacryloyl group, an acryloyl group, an acrylamide group, an allyl group, a vinyl group, a styryl group, or a combination thereof. The group containing a photopolymerizable group may be, for example, a group represented by the following formula (10). In formula (10), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 0 to 10. R ⁵ may be a hydrogen atom or a methyl group. ^{R 6} and R ⁷ may be hydrogen atoms. n may be 0. One or both of R ² and R ³ may be an aromatic group substituted with a group represented by formula (10). R ⁴ may be an aromatic group substituted with a group represented by formula (10).

One of ^R2 or ^R3 may be an aromatic group which may be substituted with a group not containing a photopolymerizable group, and the remaining one of ^R2 or ^R3 may be a group represented by formula (10). In that case, n in formula (10) is an integer of 1 to 10.

One of ^R2 or ^R3 may be an aromatic group substituted with a group containing a photopolymerizable group, and the remaining one of ^R2 or ^R3 may be a hydrogen atom or an optionally substituted aliphatic group (for example, an alkyl group having 1 to 40 carbon atoms).

X ¹ in formula (A1) may be an aromatic group having multiple carbon atoms, including two first carbon atoms bonded to -COOR ² or -COOR ³ groups, and a second carbon atom bonded to an amide group adjacent to each of the first carbon atoms or adjacent to the carbon atom adjacent to the first carbon atom. The first carbon atom and the second carbon atom adjacent to each other are directly bonded by a covalent bond. X ¹ may be a tetravalent organic group having 6 to 40 carbon atoms. The tetravalent organic group represented by X ¹ may include an optionally substituted aromatic group, an optionally substituted cyclic aliphatic group, or a combination thereof.

^X1 in formula (A1) may be a tetravalent group represented by the following formula (a1), (a2), ( ^a3 ) or (a4). These tetravalent groups are usually bonded to a carboxylate group ( ^-COOR2 group or -COOR3 group) and an amide group at the positions of the two bonds on both sides.

In formulae (a1) to (a4), R ¹⁰ represents a fluorine atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorinated hydrocarbon group having 1 to 10 carbon atoms, m1 represents an integer of 0 to 2, m2 represents an integer of 0 to 3, and m3 represents an integer of 0 to 4. A plurality of R ¹⁰ , m1, and m2 in one tetravalent group may be the same or different. In formula (a2), Z ¹ represents a direct bond, a methanediyl group, a propane-2,2-diyl group, a 1,1,1,3,3,3-hexafluoropropane-2,2-diyl group, a carbonyl group, a sulfonyl group, a thio group, a carbonyloxy group, an oxy group, or a fluorene-9,9-diyl group, and k represents an integer of 0 to 2. A plurality of Z ¹ in one tetravalent group may be the same or different. R ¹⁰ may be a fluorine atom, an alkyl group having 1 to 10 carbon atoms (such as a methyl group), or a fluorinated alkyl group having 1 to 10 carbon atoms (such as a trifluoromethyl group).

^X2 in formula (A2) may be an aromatic group having multiple carbon atoms, including one first carbon atom bonded to a ^-COOR4 group and a second carbon atom bonded to an amide group adjacent to the first carbon atom or adjacent to the carbon atom adjacent to the first carbon atom. The first carbon atom and the second carbon atom adjacent to each other are directly bonded by a covalent bond. ^X2 may be a trivalent organic group having 6 to 40 carbon atoms. The trivalent organic group represented by ^X2 may include an optionally substituted aromatic group, an optionally substituted cyclic aliphatic group, or a combination thereof.

X ² in formula (A2) may be a trivalent group represented by the following formula (a5), (a6), (a7) or (a8). R ¹⁰ , m1, m2 and m3 in formulas (a5) to (a8) are defined in the same manner as R ¹⁰ , m1, m2 and m3 in formulas (a1) to (a4). A plurality of R ¹⁰ and m3 in one trivalent group may be the same or different. These trivalent groups are usually bonded to an amide group at one bond position on one side, and bonded to a carboxylate group (-COOR ⁴ group) and an amide group at two bonds on the other side.

R ¹ in formulas (A1) and (A2) may be a divalent organic group having 6 to 40 carbon atoms. R ¹ may include an optionally substituted aromatic group, an optionally substituted cyclic aliphatic group, a siloxane group, or a combination thereof. R ¹ in formulas (A1) and (A2) may be a divalent group represented by the following formula (a10), (a11), or (a12).

In formulae (a10) and (a11), R ¹¹ represents a fluorine atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorinated hydrocarbon group having 1 to 10 carbon atoms, and m3 represents an integer of 0 to 4. A plurality of R ^11s and m3s in one divalent group may be the same or different. m3 may be 0.

In formula (a11), Z ² represents a direct bond, a methanediyl group, a propane-2,2-diyl group, a 1,1,1,3,3,3-hexafluoropropane-2,2-diyl group, a carbonyl group, a sulfonyl group, a thio group, a carbonyloxy group, an oxy group, a fluorene-9,9-diyl group, or an amide group, and k represents an integer of 0 to 2. A plurality of Z ² in one divalent group may be the same or different. R ¹¹ may be a fluorine atom, an alkyl group having 1 to 10 carbon atoms (e.g., a methyl group), or a fluorinated alkyl group having 1 to 10 carbon atoms (e.g., a trifluoromethyl group).

In formula (a12), ^Z3 represents an oxy group or an arylene group (e.g., a phenylene group), ^R12 represents an alkyl group having 1 to 10 carbon atoms (e.g., a methyl group), and p and q each independently represent an integer of 1 to 10. A plurality of ^R12 in one divalent group may be the same or different. p and q may be integers of 1 to 3.

The polyimide resin precursor may be a polymer containing only the structural unit represented by formula (A1) or (A2) as a repeating unit, or may be a polymer further containing a structural unit other than these. For example, the polyimide resin precursor may further contain a structural unit represented by the following formula (A1') or (A2'). R ¹ , X ¹ and X ² in formula (A1') and (A2') are defined in the same way as R ¹ , X ¹ and X ² in formula (A1) and (A2).

In the polyimide resin precursor, the proportion of the structural unit represented by formula (A1) or (A2) may be, for example, 50% by mass or more and 100% by mass or less, based on the mass of the polyimide resin precursor. In the polyimide resin precursor, the proportion of the structural unit represented by formula (A1) or (A2) may be, for example, 55% by mass or more, 60% by mass or more, 65% by mass or more, 70% by mass or more, 75% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, or 99% by mass or less, 98% by mass or less, 97% by mass or less, 96% by mass or less, 95% by mass or less, or 90% by mass or less, based on the mass of the polyimide resin precursor.

The weight average molecular weight of the polyimide resin precursor may be 8,000 or more and 150,000 or less, 9,000 or more and 50,000 or less, or 18,000 or more and 40,000 or less. The weight average molecular weight here may be a value measured by gel permeation chromatography and converted into standard polystyrene.

A polyimide resin precursor (polyimide resin precursor) having a structural unit represented by formula (A1) can be produced, for example, by a method including polycondensing a tetracarboxylic dianhydride with a diamine compound (NH ₂ -R ¹ -NH ₂ ) to form a polyamic acid having a carboxy group, and reacting the polyamic acid with an alcohol compound (R ² -OH, R ³ -OH) including an aromatic alcohol compound to convert at least a part of the carboxy groups in the polyamic acid to carboxylate groups. In the polyimide resin precursor obtained by this method, X ¹ is usually a residue derived from the tetracarboxylic dianhydride, and R ¹ is a residue derived from the diamine compound.

A polyimide resin precursor (polyamideimide resin precursor) having a structural unit represented by formula (A2) can be produced, for example, by a method including polyaddition of a tricarboxylic anhydride with a diamine compound (NH ₂ -R ¹ -NH ₂ ) to form a polyamic acid having a carboxy group, and reacting the polyamic acid with an alcohol compound including an aromatic alcohol compound (R ⁴ -OH) to convert at least a portion of the carboxy groups in the polyamic acid to carboxylate groups. In the polyimide resin precursor obtained by this method, X ² is usually a residue derived from a tricarboxylic anhydride, and R ¹ is a residue derived from a diamine compound.

By using both a tetracarboxylic dianhydride and a tricarboxylic anhydride as raw materials, it is also possible to obtain a polyimide resin precursor having both the structural unit represented by formula (A1) and the structural unit represented by formula (A2).

A photosensitive resin composition containing a polyimide-based resin precursor can be used to form, for example, a patterned resin film. FIG. 1 is a process diagram showing an example of a method for manufacturing a patterned resin film. The method shown in FIG. 1 includes forming a photosensitive resin film 10A containing a photosensitive resin composition on a substrate 20, irradiating a part of the photosensitive resin film 10A with active light rays hν (e.g., ultraviolet light), removing a part of the photosensitive resin film 10A to form a patterned resin film 10B, and heating the resin film 10B to form a resin film 10 containing an imide-based resin that contains a structural unit having an imide group.

The photosensitive resin film 10A can be formed by applying a photosensitive resin composition onto the substrate 20 and removing the solvent from the coating as necessary. By irradiating the active light rays hν through a mask 15 having a light-transmitting portion, a part of the photosensitive resin film 10A is irradiated with the active light rays hν. Then, a patterned resin film 10B is formed by a normal development method. The resin film 10B is heated by a heating device 30 to promote imidization, and a resin film 10 containing a polyimide resin is formed. The heating device 30 can be, for example, a heating furnace.

By heating the resin film 10B at a relatively low temperature, imidization proceeds, and a resin film 10 containing a polyimide resin can be formed. The heating temperature for imidization may be, for example, 200°C or less, 190°C or less, 180°C or less, or 170°C or less, or may be 140°C or more, or 150°C or more. The heating time for imidization may be, for example, 30 minutes or more and 180 minutes or less.

The photosensitive resin composition may contain other components as necessary in addition to the polyimide resin precursor. For example, the photosensitive resin composition may contain a solvent that dissolves or disperses the polyimide resin precursor, and may further contain a photopolymerization initiator and/or a photopolymerizable monomer.

The content of the polyimide resin precursor in the photosensitive resin composition may be 50% by mass or more and 100% by mass or less, based on the total mass of the components other than the solvent in the photosensitive resin composition.

The solvent may be a polar organic solvent. Examples of the solvent include 3-methoxy-N,N-dimethylpropionamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, dimethylsulfoxide, diethylene glycol dimethyl ether, cyclopentanone, gamma-butyrolactone, alpha-acetyl-gamma-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, and 2-octanone. These can be used alone or in combination of two or more.

The solvent content may be 30 parts by mass or more and 1,500 parts by mass or less, 100 parts by mass or more and 1,000 parts by mass or less, or 100 parts by mass or more and 860 parts by mass or less, relative to 100 parts by mass of the polyimide resin precursor.

The photopolymerization initiator may be a photoradical polymerization initiator, examples of which include benzophenone derivatives such as benzophenone, o-benzoylmethylbenzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, and fluorenone; acetophenone derivatives such as 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, and 1-hydroxycyclohexylphenyl ketone; thioxanthone derivatives such as thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, and diethylthioxanthone; benzil derivatives such as benzil, benzil dimethyl ketal, and benzil-β-methoxyethyl acetal; benzoin, and benzoin methyl ether. benzoin derivatives such as 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, and 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime; N-arylglycines such as N-phenylglycine; peroxides such as benzoyl perchloride; aromatic biimidazoles; and titanocenes. The photopolymerization initiator may be a photoacid generator, an example of which is α-(n-octanesulfonyloxyimino)-4-methoxybenzyl cyanide.

The content of the photopolymerization initiator may be 0.1 parts by mass or more and 10 parts by mass or less, or 1 part by mass or more and 8 parts by mass or less, per 100 parts by mass of the polyimide resin precursor.

The photosensitive resin composition may further include a photopolymerizable monomer. The photopolymerizable monomer is a compound having one or more photopolymerizable groups and is selected from compounds different from the polyimide precursor and the additive. The photopolymerizable group of the photopolymerizable monomer may be, for example, a methacryloyl group or an acryloyl group. The photopolymerizable monomer may be one or more selected from an acrylic acid ester of an alcohol compound, a methacrylic acid ester of an alcohol compound, an acrylamide and its derivatives, and a methacrylamide and its derivatives. The acrylic acid ester may be a monoacrylate or a polyacrylate (e.g., a diacrylate, a triacrylate, a tetraacrylate). The methacrylic acid ester may be a monomethacrylate or a polymethacrylate (e.g., a dimethacrylate, a trimethacrylate, a tetramethacrylate).

Examples of alcohol compounds that form acrylic or methacrylic esters include alkyl alcohols, alkane polyols, polyether polyols, aromatic polyols, and ethylene oxide or propylene oxide adducts of these alcohol compounds. An example of an alkyl alcohol includes isoborneol. Examples of alkane polyols include ethylene glycol, propylene glycol, neopentyl glycol, glycerol, 1,4-butanediol, 1,6-hexanediol, cyclohexanediol, trimethylolpropane, and pentaerythritol. Examples of polyether polyols include polyethylene glycol (e.g., diethylene glycol, tetraethylene glycol), and polypropylene glycol. Examples of aromatic polyols include bisphenol A and trihydroxybenzene.

The content of the photopolymerizable monomer in the photosensitive resin composition may be 1 part by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the polyimide-based resin precursor. The content of the photopolymerizable monomer may be 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, or 30 parts by mass or more, relative to 100 parts by mass of the polyimide-based resin precursor, and may be 45 parts by mass or less, or 40 parts by mass or less.

One aspect of the present disclosure relates to an amic acid ester compound represented by the following formula (I). The amic acid ester compound of formula (I) can form an imide by reaction between an amide group bonded via ^X3 and a carboxylic acid ester group, and can therefore be used to verify the imidization reactivity of a polyimide resin precursor. This compound can also be used as a photopolymerizable monomer.

In formula (I), R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents an alkyl group or an aryl group (e.g., a phenyl group), X ³ represents a methanediyl group, an ethane-1,2-diyl group, an ethene-1,2-diyl group, or a 1,2-phenylene group. A (meth)acryloyloxy group (CH ₂ ═C(R ¹⁵ )COO—) may be bonded to a carbon atom at the para position relative to the group including X ³ .

Verification Test 1. Synthesis of Amic Acid Ester Compound Amic Acid Ester Compound Ia
Succinic anhydride 1 (50.0 mmol) was reacted with aniline 2 (50.0 mmol) in THF (30 mL) at 25° C. to obtain amic acid compound 3. Amic acid compound 3 (2.5 mmol) was reacted with 4-hydroxyphenyl methacrylate 4a (2.5 mmol) in the presence of EDCI (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 3 mol) and BHT (dibutylhydroxytoluene, 1000 ppm) in THF (solvent) while increasing the temperature from 0° C. to 25° C. to generate amic acid ester compound 1a. Purified crystals of amic acid ester compound 1a (2.25 mmol) were obtained by recrystallization from a mixed solvent of hexane and acetone (mass ratio hexane:acetone=95:5).

Amic Acid Ester Compound II (Comparative Compound)
Succinic anhydride 1 (25.0 mmol) was reacted with 2-hydroxyethyl methacrylate 4b (25.0 mmol) in the presence of triethylamine (150 mmol) and BHT (dibutylhydroxytoluene, 1000 ppm) in THF (20 mL) at 25° C. to obtain dicarboxylic acid monoester compound 5. Dicarboxylic acid monoester compound 5 (2.0 mmol) was reacted with aniline 2 (2.0 mmol) in the presence of EDCI (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 2.4 mmol) in THF (5.0 mL) while increasing the temperature from 0° C. to 25° C. to produce amic acid ester compound II. Purified crystals of amic acid ester compound II (1.90 mmol) were obtained by recrystallization from a mixed solvent of hexane and acetone (mass ratio hexane:acetone=95:5).

2. Differential Scanning Calorimetry (DSC)
Differential scanning calorimetry (heating rate: 10° C./min) was performed on the amic acid ester compounds Ia and II. FIG. 2 is a DSC curve showing the relationship between the amount of heat generated and temperature. In the case of the amic acid ester compound II, endothermic heat due to imidization was observed mainly in the region of 200° C. or higher. The amic acid ester compound Ia showed a melting point and endothermic heat due to imidization at a low temperature of 160° C. or lower.

3. Reaction Test The crystals of the amic acid ester compound II were heated from 10° C. to 270° C. at a heating rate of 10° C./min. The ¹ H NMR spectrum (solvent: deuterated dimethyl sulfoxide) of the crystals was measured before heating, at 160° C., 200° C., or 270° C. The crystals of the amic acid ester compound Ia were heated from 10° C. to 160° C. at a heating rate of 10° C./min, and then heated at 160° C. for 1 hour. The ¹ H NMR spectrum (solvent: deuterated dimethyl sulfoxide) of the crystals was measured before heating, at 160° C., and at 160° C. for 1 hour. Figures 3 and 4 show ^{the 1} H NMR spectra of the amic acid ester compounds II and Ia, respectively. In the case of amic acid ester compound II, no signal assigned to the imide group was observed at 160° C., but a signal of the imide group was observed in the region of 7.4 to 7.5 ppm at temperatures of 200° C. or higher. In the case of amic acid ester compound Ia, a signal of the imide group was observed at 160° C., and it was confirmed that the imidization reaction proceeded sufficiently by heating at 160° C. for 1 hour.

The above verification tests suggest that polyimide resins can be formed at lower temperatures by introducing an aromatic alcohol ester group into the amic acid ester structure of a polyimide resin precursor.

10A: photosensitive resin film, 10: resin film containing polyimide resin, 20: substrate.

Claims (5)

The following formula (A1):

or a structural unit represented by the following formula (A2):

The structural unit includes at least one of the structural units represented by
In formula (A1), ^X1 represents a tetravalent organic group, ^R1 represents a divalent organic group, ^R2 and ^R3 each independently represent a monovalent organic group, at least one of ^R2 and ^R3 is an aromatic group which may be substituted, and at least one of ^R2 and ^R3 is a group containing a photopolymerizable group;
In formula (A2), ^X2 represents a trivalent organic group, ^R1 represents a divalent organic group, and ^R4 represents an aromatic group substituted with a group containing a photopolymerizable group.
Polyimide resin precursor. A photosensitive resin composition comprising the polyimide resin precursor according to claim 1. irradiating a part of a photosensitive resin film containing the polyimide-based resin precursor according to claim 1 with actinic rays;
removing a portion of the photosensitive resin film to form a patterned film;
heating the patterned film to form a resin film containing an imide-based resin that includes a structural unit having an imide group;
A method for producing a resin film comprising the steps of: The method according to claim 3, wherein the resin film is formed by heating the patterned film to 200°C or less. The following formula (I):

wherein R ¹⁵ represents a hydrogen atom or a methyl group, R ¹⁶ represents an alkyl group or an aryl group, and X ³ represents a methanediyl group, an ethane-1,2-diyl group, an ethene-1,2-diyl group, or a 1,2-phenylene group.

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