Method for producing a polyimide precursor, and method for producing a cured product

Abstract

To provide a method for producing a polyimide precursor that allows reduction in the number of steps for purification, and a method for producing a cured product.SOLUTION: A method for producing a polyimide precursor includes the steps of: preparing a water-containing liquid containing water and a polyimide precursor; and adding a solvent to the water-containing liquid, dissolving the polyimide precursor in the solvent.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a method for producing a polyimide precursor and a method for producing a cured product.

Background Art

[0002] In recent years, as a protective film material for semiconductor integrated circuits (LSIs), organic materials having high heat resistance such as polyimide resins have been widely applied. A protective film using a cured film of such a polyimide resin can be obtained by heating a resin film formed by applying and drying a polyimide precursor or a resin composition containing a polyimide precursor on a substrate. Alternatively, a polyimide precursor is imidized, the obtained polyimide is dissolved in a solvent to prepare a polyimide solution, and a protective film is obtained by applying and drying this polyimide solution on a substrate.

[0003] Usually, in order to remove unnecessary components, the polyimide precursor or polyimide is purified before being applied on the substrate. As a purification method, for example, as described in Reference Document 1, a method of washing a polyimide powder with a poor solvent such as methanol and performing suction filtration can be mentioned. The washing is often repeated two or more times.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the method described in Patent Document 1, since the polyimide in the reaction solvent is dried, pulverized, and then washed with a poor solvent, there is a problem that the number of steps is large. In particular, when washing is repeated, it is necessary to dry the polyimide each time, which is an extremely complicated operation and also costly. In view of these circumstances, this disclosure relates to a method for producing a polyimide precursor that can reduce the number of steps in the purification process, and a method for producing a cured product. [Means for solving the problem]

[0006] The means for solving the above problems include the following embodiments. <1> A step of preparing a water-containing solution containing water and a polyimide precursor, A step of adding a solvent to the water-containing liquid to dissolve the polyimide precursor in the solvent, A method for producing a polyimide precursor containing [the specified ingredient]. <2> The solubility parameter of the aforementioned solvent is 20 MPa. 1 / 2 ~25MPa 1 / 2 That is, <1> A method for producing the polyimide precursor described above. <3> The ratio of the amount of the solvent to the total amount of the polyimide precursor and the solvent is 50% by mass or more. <1> or <2> A method for producing the polyimide precursor described above. <4> The ratio of the amount of the solvent to the total amount of the polyimide precursor and the solvent is 95% by mass or less. <1> ~ <3> A method for producing a polyimide precursor as described in any one of the items. <5> In the water-containing solution, the ratio of the amount of water to the total amount of the polyimide precursor and the water is 50% by mass or more. <1> ~ <4> A method for producing a polyimide precursor as described in any one of the items. <6> In the water-containing liquid, the ratio of the amount of water to the total amount of the polyimide precursor and the water is 75% by mass or less. <1> ~ <5> A method for producing a polyimide precursor as described in any one of the items. <7> The polyimide precursor has polymerizable unsaturated bonds, <1> ~ <6> A method for producing a polyimide precursor as described in any one of the items. <8> The polyimide precursor has a structural unit represented by the following general formula (1): <7> A method for producing the polyimide precursor described above. [ka] (In general formula (1), X represents a tetravalent organic group and Y represents a divalent organic group. 1 and R 2 Each of these is independently a hydrogen atom, a group represented by the following general formula (2), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and R 1 and R 2 At least one of them is a group represented by the following general formula (2). [ka] (In general formula (2), R 3 ~R 5 Each of these independently represents a hydrogen atom or an aliphatic hydrocarbon group with 1 to 3 carbon atoms, and q represents an integer from 1 to 10. <9> Before the step of preparing the aforementioned water-containing liquid, The process further includes reacting a carboxylic acid halide with an amine compound to obtain a polyimide precursor. <1> ~ <8> A method for producing a polyimide precursor as described in any one of the items. <10> <1> ~ <9> A step of obtaining a polyimide precursor by a manufacturing method described in any one of the items, A step of reacting the polyimide precursor with a photopolymerization initiator to obtain a photopolymerized product, The process of heating the photopolymerized product, A method for producing a cured product containing [the specified ingredient]. [Effects of the Invention]

[0007] This disclosure provides a method for producing a polyimide precursor that can reduce the number of steps in the purification process, and a method for producing a cured product. [Modes for carrying out the invention]

[0008] The embodiments of this disclosure will be described in detail below. However, the embodiments of this disclosure are not limited to the embodiments described below. In the embodiments described below, the components (including elemental steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the embodiments of this disclosure.

[0009] In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, provided that the purpose of such process is achieved. In this disclosure, the numerical range indicated using "~" includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. In this disclosure, each component may contain multiple types of the corresponding substance. If multiple types of the substance 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 types of substances present in the composition, unless otherwise specified.

[0010] Method for producing polyimide precursors The method for producing a polyimide precursor according to this disclosure includes the steps of preparing a water-containing solution containing water and a polyimide precursor, and adding a solvent to the water-containing solution to dissolve the polyimide precursor in the solvent. In the method for producing the polyimide precursor of this disclosure, as preparation for purification, a water-containing solution containing water and the polyimide precursor is prepared. This water-containing solution may contain a reaction solvent such as N-methylpyrrolidone used in the synthesis, and in this case, several steps such as drying and grinding of the polyimide precursor can be omitted. Furthermore, if the drying step is omitted, polymerization of the polyimide precursor due to heating during drying is suppressed, and as a result, an unintended increase in molecular weight is suppressed, making it easier to control the molecular weight of the polyimide precursor. Furthermore, the polyimide precursor precipitated in the water-containing solution is not filtered out, and a solvent is added to the water-containing solution containing the precipitated polyimide precursor, thus eliminating the filtration step.

[0011] In the purification of polyimide precursors, processes such as drying, grinding, and filtration occupy equipment for extended periods, leading to high costs. The method for producing polyimide precursors described herein eliminates these processes, thus enabling cost reduction. Furthermore, as the number of steps increases, impurities are more likely to be introduced from the equipment used in each step. In the method for producing the polyimide precursor of this disclosure, the number of steps is reduced, so the introduction of impurities from the equipment is suppressed, and the number of purification cycles can be reduced. Therefore, it is possible to further reduce costs.

[0012] (Polyimide precursor) First, let's explain the polyimide precursors used for purification. The polyimide precursor may be a polyamic acid, which is a reaction product of a carboxylic acid and an amine compound, or a polyamic acid ester, which is a reaction product of a partially esterified carboxylic acid ester and an amine compound. From the viewpoint of use in negative-type photosensitive resin compositions, it is preferable that the polyimide precursor has polymerizable unsaturated bonds. Hereinafter, a polyimide precursor having polymerizable unsaturated bonds may be referred to as an "unsaturated polyimide precursor." Examples of polymerizable unsaturated bonds include carbon-carbon double bonds.

[0013] The unsaturated polyimide precursor may be, for example, a polyimide precursor having a structural unit represented by the following general formula (1). Since the unsaturated polyimide precursor has a structural unit represented by the general formula (1), it has a high transmittance of i-line and tends to form a good cured product even when cured at 380 °C or lower.

[0014]

Chemical formula

[0015] In the general formula (1), X represents a tetravalent organic group, and Y represents a divalent organic group. R 1 and R 2 are each independently a hydrogen atom, a group represented by the following general formula (2), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and at least one of R 1 and R 2 is a group represented by the following general formula (2).

[0016]

Chemical formula

[0017] In the general formula (2), R 3 to R 5 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.

[0018] From the viewpoint of use in a negative photosensitive resin composition, the content of the structural unit represented by the following general formula (1) in the unsaturated polyimide precursor is preferably 50 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more, based on all the structural units contained in the unsaturated polyimide precursor. The upper limit is not particularly limited and may be 100 mol%.

[0019] The unsaturated polyimide precursor may be synthesized using tetracarboxylic dianhydride and a diamine compound. In this case, X corresponds to a residue derived from tetracarboxylic dianhydride, and Y corresponds to a residue derived from the diamine compound. The unsaturated polyimide precursor may also be synthesized using tetracarboxylic acid instead of tetracarboxylic dianhydride.

[0020] In general formula (1), the tetravalent organic group represented by X preferably has 4 to 25 carbon atoms, more preferably 4 to 13, and even more preferably 6 to 12 carbon atoms. The tetravalent organic group represented by X may include an aromatic ring. When the tetravalent organic group represented by X includes an aromatic ring, examples of aromatic rings include a benzene ring, a naphthalene ring, and a phenanthrene ring. Among these, a benzene ring is preferred from the viewpoint of improving the light transmittance of the polyamic acid ester, which is a polyimide precursor, in the ultraviolet region. When the tetravalent organic group represented by X contains an aromatic ring, each aromatic ring may have a substituent or be unsubstituted. Examples of substituents on the aromatic ring include alkyl groups, fluorine atoms, alkyl halides, hydroxyl groups, amino groups, and the like. When the tetravalent organic group represented by X contains a benzene ring, it is preferable that the tetravalent organic group represented by X contains 1 to 4 benzene rings, more preferably 1 to 3 benzene rings, and even more preferably 1 or 2 benzene rings. When the tetravalent organic group represented by X contains two or more benzene rings, each benzene ring may be linked by a single bond, or by an alkylene group, a halogenated alkylene group, a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-), or a silylene bond (-Si(R)). A )2-;R A Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group. ) Siloxane bond (-O-(Si(R B )2-O-) n ;R BEach of these independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or 2 or more. The rings may be linked by linking groups such as , or by a composite linking group formed by combining at least two of these linking groups. Alternatively, two benzene rings may be linked at two locations by a single bond and at least one of a linking group, forming a five-membered or six-membered ring containing a linking group between the two benzene rings.

[0021] In general formula (1), -COOR 1 Base and -COOR 2 When the two groups are bonded to the same aromatic ring, it is preferable that they are in the meta or para position relative to each other.

[0022] Specific examples of the tetravalent organic group represented by X include the groups represented by the following formulas (A) to (E), but this disclosure is not limited to these specific examples.

[0023] [ka]

[0024] In general formula (D), J and K are independently a single bond, a methylene group, a halide methylene group, a carbonyl group, a sulfonyl group, an ether bond (-O-), a sulfide bond (-S-), or a silylene bond (-Si(R A )2-;R A Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group. ) and both J and K cannot be single bonds.

[0025] In general formula (E), L is 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-), or a silylene bond (-Si(R A )2-;R A Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group. ), Siloxane bond (-O-(Si(R B )2-O-) n ;R BEach of these independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or more. Alternatively, L may represent a divalent group formed by combining at least two of these. Furthermore, L may be represented by the following formula (L1).

[0026] [ka]

[0027] The alkylene group represented by L 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 alkylene groups represented by L in general formula (E) include linear alkylene groups such as methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, and hexamethylene group; methylmethylene group, methylethylene group, ethylmethylene group, dimethylmethylene group (isopropylidene group), 1,1-dimethylethylene group, 1-methyltrimethylene group, 2-methyltrimethylene group, ethylethylene group, 1-methyltetramethylene group, 2-methyltetramethylene group, 1-ethyltrimethylene group, and 2-ethyltrimethylene group. Examples include branched alkylene groups such as 1,1-dimethyltrimethylene 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. Among these, methylene groups and ethylene groups are preferred.

[0028] The halogenated alkylene group represented by L 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 halogenated alkylene groups represented by L in general formula (E) include alkylene groups in which at least one hydrogen atom in the alkylene group represented by L in general formula (E) above is substituted with a halogen atom such as a fluorine atom or a chlorine atom. Among these, fluoromethylene groups, difluoromethylene groups, and hexafluorodimethylmethylene groups are preferred.

[0029] R included in the above silylene bond or siloxane bond A or R B The alkyl group represented is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably an alkyl group having 1 or 2 carbon atoms. A or R B Specific examples of alkyl groups represented by include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, and the like.

[0030] The combination of J and K in general formula (D) is not particularly limited, and combinations such as a methylene group and an ether bond, a methylene group and a sulfide bond, and a carbonyl group and an ether bond are preferred. In general formula (E), L is preferably a single bond, an ether bond, or a carbonyl group.

[0031] R in general formula (1) 1 and R 2 The number of carbon atoms in the aliphatic hydrocarbon group represented by R is 1 to 4, preferably 1 or 2. 1 and R 2Specific examples of aliphatic hydrocarbon groups represented by include methyl group, ethyl group, n-propyl group, isopropyl group, and n-butyl group.

[0032] R in general formula (2) 3 ~R 5 The aliphatic hydrocarbon group represented by has 1 to 3 carbon atoms, preferably 1 or 2. 3 ~R 5 Specific examples of the aliphatic hydrocarbon group represented by include the methyl group, ethyl group, n-propyl group, isopropyl group, etc., with the methyl group being preferred.

[0033] R in general formula (2) 3 ~R 5 As for combinations, R 3 and R 4 is a hydrogen atom, and R 5 A combination of hydrogen atoms or methyl groups is preferred.

[0034] In general formula (2), q is preferably an integer between 1 and 10, more preferably an integer between 2 and 5, and even more preferably 2 or 3.

[0035] In general formula (1), R 1 and R 2 Preferably, at least one of them is a group represented by general formula (2), R 1 and R 2 It is more preferable that both are groups represented by general formula (2).

[0036] If X is a residue derived from a tetracarboxylic dianhydride, specific examples of the tetracarboxylic dianhydrides from which the residue originates include pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic 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 Examples include 3,3-hexafluoro-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 acid dianhydride, 4,4'-sulfonyldiphthalic acid dianhydride, and 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride.

[0037] In general formula (1), the divalent organic group represented by Y preferably has 1 to 30 carbon atoms, more preferably 5 to 25, and even more preferably 10 to 20 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, it is preferable that the divalent organic group represented by Y is a divalent aromatic group.

[0038] Specific examples of divalent aromatic groups represented by Y include the groups represented by the following general formulas (F) and (G).

[0039] [ka]

[0040] In general formula (F) or general formula (G), R independently represents an alkyl group, an alkoxy group, a halogenated alkyl group, a carboxyl group, or a phenyl group, and n independently represents an integer from 0 to 4. In general formula (G), D is 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-), or a silylene bond (-Si(R) A )2-;R A Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group. ), Siloxane bond (-O-(Si(R B )2-O-) n ;R B Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or more. ) or a divalent group formed by combining at least two of these. Furthermore, D may be a structure represented by the above formula (L1).

[0041] 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 even more preferably an alkyl group having 1 or 4 carbon atoms. Specific examples of alkyl groups represented by R in general formula (F) or general formula (G) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, and the like.

[0042] The alkoxy group represented by R in general formula (F) or 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 even more preferably an alkoxy group having 1 or 4 carbon atoms. Specific examples of the alkoxy group represented by R in general formula (F) or general formula (G) include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, s-butoxy group, t-butoxy group, and the like.

[0043] The halogenated alkyl group represented by R in general formula (F) or general formula (G) is preferably a halogenated alkyl group having 1 to 10 carbon atoms, more preferably a halogenated alkyl group having 1 to 5 carbon atoms, and even more preferably a halogenated alkyl group having 1 or 2 carbon atoms. Specific examples of halogenated alkyl groups represented by R in general formula (F) or general formula (G) include alkyl groups in which at least one hydrogen atom 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, fluoromethyl groups, difluoromethyl groups, trifluoromethyl groups, etc., are preferred.

[0044] In general formula (F) or general formula (G), n is independently preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0045] Furthermore, D may be a divalent group represented by the following formula (D1) or (D2). -Q-Ar-Q- (D1) -Q-Ar-Q-Ar-Q- (D2) In general formula (D1) or general formula (D2), Ar represents a phenylene group or naphthylene group which may have substituents. Q independently 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-), or a silylene bond (-Si(R)). A )2-;RA Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group. ), Siloxane bond (-O-(Si(R B )2-O-) n ;R B Each of these independently represents a hydrogen atom, an alkyl group, or a phenyl group, and n represents an integer of 1 or more. ) or a divalent group formed by combining at least two of these. In general formulas (D1) and (D2), the relative positions of the two Q atoms bonded to each Ar atom may be ortho, meta, or para. Specific examples of substituents that may be present on a phenylene group or naphthylene group represented by Ar are the same as those for the group represented by R in general formula (F) or general formula (G). The number of substituents that may be present on a phenylene group or naphthylene group represented by Ar is not particularly limited.

[0046] The specific examples of D in general formula (G), excluding general formulas (D1) and (D2), and the specific examples of Q in general formulas (D1) and (D2), are the same as the specific examples of L in general formula (E). In general formula (G), D is preferably a single bond or an ether bond.

[0047] Specific examples of divalent aliphatic groups 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.

[0048] The linear or branched alkylene group represented by Y is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and even more preferably an alkylene group having 1 to 3 carbon atoms. Specific examples of alkylene groups represented by Y include tetramethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, dodecamethylene, 2-methylpentamethylene, 2-methylhexamethylene, 2-methylheptamethylene, 2-methyloctamethylene, 2-methylnonamethylene, and 2-methyldecamethylene.

[0049] The cycloalkylene group represented by Y is preferably a cycloalkylene group having 3 to 20 carbon atoms, more preferably a cycloalkylene group having 3 to 10 carbon atoms, and even more preferably a cycloalkylene group having 3 to 6 carbon atoms. Specific examples of cycloalkylene groups represented by Y include cyclopropylene and cyclohexylene groups.

[0050] 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. Among these, polyethylene oxide structure or polypropylene oxide structure is preferred as the polyalkylene 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 one type or two or more types.

[0051] Examples of divalent groups having a polysiloxane structure represented by Y include divalent groups having a polysiloxane structure in which the silicon atoms in the polysiloxane structure are bonded to hydrogen atoms, alkyl groups having 1 to 20 carbon atoms, or aryl groups having 6 to 18 carbon atoms. Specific examples of C1-C20 alkyl groups that bond to silicon atoms in the polysiloxane structure include methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-octyl, 2-ethylhexyl, and n-dodecyl groups. Among these, the methyl group is preferred. 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 substituents on the aryl group include halogen atoms, alkoxy groups, and hydroxyl groups. Specific examples of aryl groups having 6 to 18 carbon atoms include phenyl groups, naphthyl groups, and benzyl groups. Among these, the 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 one type or two or more types. The silicon atoms constituting the divalent group having a polysiloxane structure represented by Y may be bonded to the NH group in general formula (1) via an alkylene group such as a methylene group or an ethylene group, or an arylene group such as a phenylene group, etc.

[0052] If Y corresponds to a residue derived from a diamine compound, specific examples of the diamine compounds from which that residue originates include 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,5-diaminobenzoic acid, p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 1,5-diaminonaphthalene, benzidine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, and 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-Diisopropylaniline), 2,4-Diaminomesitylene, 1,5-Diaminonaphthalene, 4,4'-Benzphenonediamine, Bis-{4-(4'-Aminphenoxy)phenyl}sulfone, 2,2-Bis{4-(4'-Aminphenoxy)phenyl}propane, 2,2-Bis{4-(4'-Aminphenoxy)phenyl}hexafluoropropane, 4,4'-(m-Phenylenediisopropylidene)dianiline, 4,4'-(p-Phenylenediisopropyl Lyden)dianiline, 1,7-bis(4-aminophenoxy)naphthalene, 4,4'-bis(4-aminophenoxy)biphenyl, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 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, 2,2-bis(4-aminophenyl)hexafluoropropane, 9,Examples include 9-bis(4-aminophenyl)fluorene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenylsulfone, 1,4-diaminobutane, 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, and diaminopolysiloxane. Diamine compounds may be used individually or in combination of two or more.

[0053] The combination of the tetravalent organic group represented by X and the divalent organic group represented by Y in general formula (1) is not particularly limited. In one embodiment, from the viewpoint of low-temperature curability that allows the cyclization reaction of polyimide to proceed at low temperatures, a combination is preferred in general formula (1) where X is represented by general formula (E) and L in general formula (E) is a group represented by a single bond or an ether bond, and Y is represented by general formula (G) and D in general formula (G) is a group represented by a single bond or an ether bond.

[0054] Furthermore, in one embodiment, from the viewpoint of transmittance that allows the irradiated light to reach the bottom of the film during exposure, a combination is preferred in general formula (1) where X is represented by general formula (E) and L in general formula (E) is a group represented by an ether bond, and Y is represented by general formula (G) and D in general formula (G) is a group represented by an ether bond. In this case, Y may also include a group represented by general formula (F). When Y is represented by a group represented by general formula (G) and D in general formula (G) is an ether bond and a group represented by general formula (F) are used in combination, the proportion of the group represented by general formula (F) in Y is preferably 5 mol% to 30 mol%, and more preferably 6 mol% to 15 mol%.

[0055] Furthermore, in certain embodiments, from the viewpoint of toughness of the cured film, examples include a configuration in which at least a portion of X in general formula (1) is a group represented by formula (A), and Y is a combination of any divalent organic group. From the viewpoint of low-temperature curability, permeability, and toughness, X may be a combination of a group represented by formula (A) and a group represented by general formula (E). When X is a combination of a group represented by formula (A) and a group represented by general formula (E), the proportion of formula (A) in X is preferably 10 mol% to 80 mol%, and more preferably 30 mol% to 70 mol%.

[0056] The unsaturated polyimide precursor may have structural units other than the structural unit represented by general formula (1). Other structural units other than the structural unit represented by general formula (1) include R in general formula (1). 1 and R 2 However, each is independently a structural unit that is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, that is, R in general formula (1) 1 and R 2 These include structural units that are not represented by general formula (2).

[0057] There are no particular restrictions on the molecular weight of the polyimide precursor. The weight-average molecular weight of the polyimide precursor is preferably 10,000 to 100,000, more preferably 15,000 to 100,000, even more preferably 20,000 to 85,000, particularly preferably 30,000 to 60,000, and most preferably 37,000 to 43,000. When using a polyimide precursor in a photosensitive resin composition, it is preferable that the weight-average molecular weight of the polyimide precursor be 10,000 or more, from the viewpoint of sufficiently reducing the stress after curing. Furthermore, from the viewpoint of improving the solubility of the polyimide precursor in solvents and the handling of the polyimide precursor solution, it is preferable that the weight-average molecular weight of the polyimide precursor be 100,000 or less. The weight-average molecular weight can be measured by gel permeation chromatography (GPC) and determined by conversion using a standard polystyrene calibration curve. Details of the GPC measurement conditions can be found in the examples described later.

[0058] (Method for synthesizing polyimide precursors) The method for synthesizing the polyimide precursor is not particularly limited, and it may be synthesized using a carboxylic acid having two or more carboxyl groups and an amine compound. From the viewpoint of obtaining a linear polyimide precursor, it is preferable that the compound having two or more carboxyl groups is a compound having two carboxyl groups. The carboxylic acid having two or more carboxyl groups may be used alone or in combination of two or more.

[0059] Acid anhydrides may be used instead of carboxylic acids. In this disclosure, acid anhydrides having one or more cyclic anhydride structures may be described as carboxylic acids having two or more carboxyl groups. Acid anhydrides preferably have two or more cyclic anhydride structures, and more preferably have two cyclic anhydride structures. Acid anhydrides may be used individually or in combination of two or more. Acid anhydrides may include acid anhydrides represented by the following general formula (3).

[0060] [ka]

[0061] In general formula (3), X is the same as X in general formula (1).

[0062] The carboxylic acid may be partially esterified. The partially esterified carboxylic acid has two or more carboxyl groups, preferably two carboxyl groups. The partially esterified carboxylic acid may be used alone or in combination of two or more.

[0063] Examples of partially esterified carboxylic acids include tetracarboxylic acid diesters. Partially esterified carboxylic acids may also include tetracarboxylic acid diesters represented by the following general formula (4).

[0064] [ka]

[0065] In general formula (4), X, R 1 and R 2 These are X and R in general formula (1). 1 and R 2 These are synonymous with each other.

[0066] The partially esterified carboxylic acid preferably includes at least one selected from the group consisting of esterified pyromellitic dianhydride and esterified 4,4'-oxydiphthalic acid dianhydride.

[0067] Alternatively, a carboxylic acid halide may be used instead of a carboxylic acid. In other words, a polyimide precursor may be obtained by reacting a carboxylic acid halide with an amine compound. One carboxylic acid halide may be used alone, or two or more may be used in combination.

[0068] As the carboxylic acid halide, carboxylic acid chlorides are preferred. Hereinafter, the method of synthesizing polyimide precursors using carboxylic acid chlorides may be referred to as the "acid chloride method." In the acid chloride method, the halogenation rate of the carboxyl group can be controlled, which tends to make it easier to control the molecular weight of the polyimide precursor.

[0069] Carboxylic acid halides have two or more carboxylic acid halide groups. From the viewpoint of obtaining linear polyimide precursors, carboxylic acid halides are preferably compounds having two carboxylic acid halide groups.

[0070] Carboxylic acid halides may be partially esterified. Partially esterified carboxylic acid halides have two or more carboxylic acid halide groups, preferably two carboxylic acid halide groups. Partially esterified carboxylic acid halides may be used individually or in combination of two or more. Partially esterified carboxylic acid halides may include compounds represented by the following general formula (5).

[0071] [ka]

[0072] In general formula (5), X, R 1 and R 2 These are X and R in general formula (1). 1 and R 2 These are synonymous. 11 and X 12 Each of these independently represents a halogen atom, preferably a chlorine atom.

[0073] Examples of partially esterified carboxylic acid halides include tetracarboxylic acid diester dichlorides. Tetracarboxylic acid diester dichlorides may include compounds represented by the following general formula (6).

[0074] [ka]

[0075] In general formula (6), X, R 1 and R 2 These are X and R in general formula (1). 1 and R 2 These are synonymous with each other.

[0076] The partially esterified carboxylic acid halide preferably includes at least one selected from the group consisting of chlorides of esterified pyromellitic dianhydride and chlorides of esterified 4,4'-oxydiphthalic acid dianhydride.

[0077] Unsaturated polyimide precursors having structural units represented by general formula (1) can be synthesized, for example, by the following method. A tetracarboxylic dianhydride represented by general formula (3) and a monoalcohol compound are reacted in an organic solvent such as N-methyl-2-pyrrolidone to form a diester derivative, and then the diester derivative is subjected to a condensation reaction with a diamine compound represented by H2N-Y-NH2. A tetracarboxylic dianhydride represented by general formula (3) is reacted with a diamine compound represented by H2N-Y-NH2 in an organic solvent to obtain a polyamic acid, and a monoalcohol compound is added and reacted in an organic solvent to introduce an ester group. A tetracarboxylic dianhydride represented by general formula (3) is reacted with a monoalcohol compound to produce a diester derivative, which is then converted to an acid chloride by reacting with a chlorinating agent such as thionyl chloride. Subsequently, the acid chloride is reacted with a diamine compound represented by H2N-Y-NH2 (acid chloride method). A tetracarboxylic dianhydride represented by general formula (3) is reacted with a monoalcohol compound to form a diester derivative, and then the diester derivative is reacted with a diamine compound represented by H2N-Y-NH2 in the presence of a carbodiimide compound. A polyamic acid is obtained by reacting a tetracarboxylic dianhydride represented by general formula (3) with a diamine compound represented by H2N-Y-NH2. The polyamic acid is then isoimide-treated in the presence of trifluoroacetic anhydride, and subsequently reacted with a monoalcohol compound. In this case, a portion of the tetracarboxylic dianhydride may be reacted with the monoalcohol compound beforehand, and the partially esterified tetracarboxylic dianhydride may be reacted with the diamine compound represented by H2N-Y-NH2 to obtain the polyamic acid.

[0078] Here, Y in the diamine compound represented by H2N-Y-NH2 is synonymous with Y in general formula (1).

[0079] Examples of monoalcohol compounds include methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, glycerol diacrylate, 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol, glycerol dimethacrylate, pentaerythritol triacrylate, and pentaerythritol trimethacrylate.

[0080] The tetracarboxylic dianhydride represented by general formula (3), the diamine compound represented by H2N-Y-NH2, and the monoalcohol compound may each be used individually or in combination of two or more.

[0081] Below is an outline of a scheme for synthesizing a polyimide precursor represented by general formula (1') by reacting a diesterified tetracarboxylic dianhydride represented by general formula (3) with a monoalcohol represented by ROH, and then reacting it with thionyl chloride as a halogenating agent, as an example of the acid chloride method. The embodiments of this disclosure are not limited to the following examples.

[0082] [ka]

[0083] In the diagram above, R independently represents a substituted or unsubstituted alkyl group, X independently represents a tetravalent organic group, and Y independently represents a divalent organic group.

[0084] When a tetracarboxylic acid dianhydride is reacted with a monoalcohol compound to obtain a tetracarboxylic acid diester, it is preferable to react at least 2 moles of the monoalcohol compound with 1 mole of tetracarboxylic acid dianhydride in the presence of a basic catalyst. From the viewpoint of suppressing the amount of unreacted monoalcohol compound, the amount of monoalcohol compound used is preferably 2.0 to 2.5 moles, more preferably 2.0 to 2.3 moles, and even more preferably 2.0 to 2.2 moles, per mole of tetracarboxylic acid dianhydride represented by general formula (3).

[0085] Basic catalysts used when reacting tetracarboxylic dianhydrides with monoalcohol compounds include 1,8-diazabicyclo[5.4.0]undeca-7-ene and 1,5-diazabicyclo[4.3.0]nona-5-ene.

[0086] When a tetracarboxylic acid diester is obtained by reacting a tetracarboxylic acid dianhydride with a monoalcohol compound, the reaction solvent can be any solvent capable of dissolving the tetracarboxylic acid dianhydride and the tetracarboxylic acid diester, such as N-methyl-2-pyrrolidone and diethylene glycol dimethyl ether.

[0087] When using two or more types of tetracarboxylic dianhydrides as raw materials, each tetracarboxylic dianhydride may be individually converted into a tetracarboxylic diester, and then these may be mixed before use. Alternatively, two or more types of tetracarboxylic dianhydrides may be mixed in advance, and a mixture of tetracarboxylic diesters may be synthesized all at once.

[0088] Examples of halogenating agents include chlorinating agents and iodinating agents, with chlorinating agents being preferred from the viewpoint of reactivity and ease of handling. Examples of halogenating agents include thionyl chloride and oxalyl chloride.

[0089] The amount of halogenating agent used is preferably 2.00 times or more in equivalent ratio to the tetracarboxylic acid diester. Furthermore, the amount of halogenating agent used is preferably an excess amount relative to the amount of tetracarboxylic acid diester being reacted with. In one embodiment, the amount of halogenating agent added may exceed 2.00 times, 2.05 times or more, 2.10 times or more, 2.20 times or more, 2.30 times or more, 2.40 times or more, 2.50 times or more, or 2.60 times or more in equivalent ratio to the tetracarboxylic acid diester. When the amount of halogenated agent added is within the above range, the halogenation rate is sufficiently increased, and the range of adjustment of the halogenation rate by subsequent addition of water is widened. Also, in one embodiment, from the viewpoint of suppressing unreacted halogenating agent, the amount of halogenating agent added may be 5.00 times or less, 4.00 times or less, 3.00 times or less, or 2.80 times or less in equivalent ratio to the tetracarboxylic acid diester. From this viewpoint, the halogenating agent may be added in an equivalent ratio of 2.05 to 5.00 times, 2.05 to 4.00 times, 2.05 to 3.00 times, or 2.05 to 2.80 times relative to the tetracarboxylic acid diester.

[0090] The halogenation rate of the tetracarboxylic acid diester by halogenation with a halogenating agent may be, for example, 90% or more, 95% or more, 96% or more, 97% or more, or 98% or more. The closer the halogenation rate is to 100%, the wider the range of adjustment for the halogenation rate by subsequent addition of water.

[0091] The temperature at which the halogenating agent is reacted with the tetracarboxylic acid diester may be 0°C to 20°C, or from the viewpoint of controlling side reactions, it may be 0°C to 15°C or 0°C to 10°C. The reaction time for the halogenating agent with the tetracarboxylic acid diester may be 0.5 to 8 hours, 0.5 to 6 hours, or 0.5 to 3 hours from the viewpoint of controlling side reactions.

[0092] When reacting carboxylic acid chlorides with amine compounds, basic compounds may be used in combination. The basic compounds are used to capture the hydrogen chloride generated when the carboxylic acid chloride reacts with the amine compound. Examples of basic compounds that can be used include pyridine, 4-dimethylaminopyridine, and triethylamine. From the viewpoint of increasing the molecular weight of the resulting polyimide precursor and improving the stress after curing, the amount of basic compound used is preferably 1.5 to 2.5 moles, more preferably 1.7 to 2.4 moles, and even more preferably 1.8 to 2.3 moles per mole of chlorinating agent.

[0093] (Method for purifying polyimide precursors) The purification of the polyimide precursor includes a step of preparing a water-containing solution containing water and the polyimide precursor (hereinafter also referred to as the "water-containing solution preparation step") and a step of adding a solvent to the water-containing solution to dissolve the polyimide precursor in the solvent (hereinafter also referred to as the "redissolution step"). As described above, the polyimide precursor is synthesized in the reaction solvent. When water is added to the resulting polyimide precursor solution, the polyimide precursor precipitates, while unwanted components remain in the water. Then, when a solvent is added to this water-containing solution of polyimide and water, the polyimide precursor redissolves in the solvent.

[0094] For example, when polyimide precursors are synthesized by the acid chloride method, the resulting polyimide precursor solution contains chlorine. Since chlorine can cause corrosion of semiconductor integrated circuits, it is desirable to remove it before applying it to the semiconductor integrated circuit. When water is added to the polyimide precursor solution, the chlorine remains dissolved in the water, and the polyimide precursor precipitates. Therefore, this process can reduce the amount of chlorine in the polyimide precursor.

[0095] In the water-containing solution, the ratio of water to the total amount of polyimide precursor and water is preferably 50% by mass or more, and more preferably 66% by mass or more. When the above ratio is 66% by mass or more, the removal of unwanted components such as chlorine tends to be excellent. Furthermore, in the water-containing solution, the ratio of water to the total amount of polyimide precursor and water is preferably 75% by mass or less, and more preferably 66% by mass or less, as this tends to reduce the amount of waste liquid and suppress separation of the solution while maintaining excellent washing performance.

[0096] From the viewpoint of further removing unwanted components, the water-containing liquid may be stirred. The stirring conditions can be appropriately set depending on the amount of liquid to be treated, viscosity, size of the stirring container, etc. For example, the stirring speed may be 200 rpm (revolutions / minute) or more, or 500 rpm or more. Alternatively, the stirring speed may be 1000 rpm (revolutions / minute) or less, or 1500 rpm (revolutions / minute) or less. The stirring time may be 10 minutes or more, or 30 minutes or more. Alternatively, the stirring time may be 60 minutes or less, or 120 minutes or less.

[0097] The solvent used in the redissolution process can be any solvent that dissolves the polyimide precursor. For example, the solvent solubility parameter is 20 MPa. 1 / 2 ~25MPa 1 / 2 It may also be 20 MPa 1 / 2 ~30 MPa 1 / 2 This may also be the case. When the solubility parameter is within the above range, it interacts with both the polyimide precursor and water, resulting in excellent washing performance and a tendency to reduce the number of repetitions in the purification process.

[0098] The solubility parameter δ of a solvent is determined by the molar evaporation energy ΔE (J / mol) of the solvent and the molar volume V (cm³). 3 It is calculated using the following formula ( / mol). δ = (ΔE / V) 1 / 2 [MPa 1 / 2 ]

[0099] The specific gravity of the solvent, with water set to 1, may be between 4 and 5, or even greater than 5. Solvents with a specific gravity within this range tend to exhibit superior cleaning performance.

[0100] The solvent may be used alone or in combination of two or more types. Specific examples of solvents include acetone, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), 3-methoxy-N,N-dimethylpropanamide, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), ethyl lactate (EL), tetramethylurea (TMU), 1,3-dimethyl-2-imidazolidinone (DMI), methyl sulfoxide (DMSO), isopropanol (IPA), γ-butyrolactone (GBL), and methyl ethyl ketone (MEK).

[0101] The solvent is preferably a compound having a carbonyl group, more preferably a compound having a carbonyl group and an electron-donating group directly bonded to the carbonyl group, and even more preferably a compound having a carbonyl group and an alkyl or amino group directly bonded to the carbonyl group.

[0102] Among the solvents listed above, acetone, NMP, NEP, 3-methoxy-N,N-dimethylpropanamide, DMF, DMAc, EL, TMU, and DMI are preferred, acetone, NMP, NEP, 3-methoxy-N,N-dimethylpropanamide, and TMU are more preferred, and acetone is even more preferred.

[0103] The combinations of two or more solvents used together are not particularly limited. Examples include combinations of NMP with 3-methoxy-N,N-dimethylpropanamide, NMP with acetone, NMP with DMSO, NMP with IPA, and acetone with methoxy-N,N-dimethylpropanamide. The combinations of NMP with 3-methoxy-N,N-dimethylpropanamide and NMP with 3-methoxy-N,N-dimethylpropanamide are more preferred.

[0104] When using two or more solvents in combination, the mixing ratio of each solvent is not particularly limited. For example, when using NMP in combination with another solvent, the mixing ratio of NMP to the other solvent (NMP:other solvent) may be 1:1 to 1:4 or 4:1 to 1:1 on a volume basis. Similarly, when using acetone in combination with another solvent, the mixing ratio of acetone to the other solvent (acetone:other solvent) may be 1:1 to 1:4 or 4:1 to 1:1 on a volume basis.

[0105] If the solvent used in the redissolution step differs from the reaction solvent used in the synthesis, it is possible to substitute the reaction solvent with another solvent. While NMP is often used as the reaction solvent, NMP-free compositions (e.g., photosensitive resin compositions) are sometimes required. In such cases, this requirement can be met by using a solvent other than NMP in the redissolution step. Furthermore, this method allows for solvent substitution without a drying step, thus reducing costs.

[0106] In the redissolution step, the ratio of the amount of solvent to the total amount of polyimide precursor and solvent is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. When the ratio of solvent is within the above range, the chlorine removal efficiency tends to be superior. Furthermore, the ratio of the amount of solvent to the total amount of polyimide precursor and solvent is preferably 95% by mass or less.

[0107] In the redissolution process, it is preferable that the solution obtained by adding a solvent to the water-containing solution (also called the "redissolution solution") is acidic. When the redissolution solution is acidic, the filterability is excellent when water is added to the redissolution solution after the redissolution process to recrystallize and filter out the precipitated polyimide precursor, and the filtration time tends to be shortened. The pH of the redissolution solution is preferably 3.5 or less, more preferably 3.0 or less, and even more preferably 2.9 or less.

[0108] To make the redissolving solution acidic, an acid may be added. The type of acid is not particularly limited, but from the viewpoint of suppressing corrosion, an organic acid is preferred, such as acetic acid or citric acid.

[0109] It is preferable to allow the mixture to stand after adding the solvent. The standing time can be appropriately set depending on the volume and viscosity of the liquid being processed, the size of the stirring vessel, etc. For example, the standing time may be 30 minutes or more.

[0110] To extract the purified polyimide precursor from the redissolved solution obtained in the redissolution process, the redissolved solution should be added dropwise to at least four times the total volume (by volume) of water to induce recrystallization, and the solid components should be filtered off.

[0111] The water-containing solution preparation step and the redissolution step are considered as one set, and two or more sets may be repeated. Repeating the process two or more times will remove more unwanted components. For example, in the second set, the redissolved solution obtained in the first redissolution step can be dropped into water at least four times the volume of the total redissolved solution to filter out the polyimide precursor, and the obtained polyimide precursor can be redissolved in a solvent again to reprecipitation and remove impurities.

[0112] After the redissolution process, the polyimide precursor solution from which water and impurities have been removed may be used as a coating solution to be applied to a substrate. Alternatively, the polyimide precursor solution, from which water and impurities have been removed after the redissolution process, may be dried to obtain a powdered polyimide precursor.

[0113] ≪Method for manufacturing hardened products≫ The method for producing a cured product according to this disclosure includes the steps of: obtaining a polyimide precursor by the method for producing a product according to this disclosure as described above; reacting the polyimide precursor with a photopolymerization initiator to obtain a photopolymer; and heating the photopolymer. The photopolymerization initiator and, if necessary, polymerizable monomers, coupling agents, solvents, thermal polymerization initiators, sensitizers, stabilizers, surfactants, leveling agents, rust inhibitors, and other components can be those commonly used in the art.

[0114] The photopolymerization initiator is not particularly limited as long as it is a compound that can generate radicals upon irradiation with active light. Examples of photopolymerization initiators include benzophenone; benzophenone derivatives such as N,N'-tetramethyl-4,4'-diaminobenzophenone (Michler ketone), N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, o-methyl benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, fluorenone, etc.; acetophenone; 2,2-di Acetophenone derivatives such as ethoxyacetophenone, 3'-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, and 1-hydroxycyclohexylphenyl ketone; thioxanthone; thioxanthone derivatives such as 2-methylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, and diethylthioxanthone; benzyl; benzyl dimethyl ketal and benzyl-β-methoxyethyl acetal; benzoin; benzoin Benzoin derivatives such as benzoin ether, benzoin ethyl ether, benzoin phenyl ether, methyl benzoin, ethyl benzoin, and propyl benzoin; 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-phenyl-1,2-propanedione Oxime derivatives such as cymdione-2-(O-benzoyl)oxime, 1,3-diphenylpropanetrione-2-(O-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxypropanetrione-2-(O-benzoyl)oxime, 1,2-octanedione, 1-[4-(phenylthio)phenyl]-,2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime); N-arylglycines such as N-phenylglycine;Examples include peroxides such as benzoyl perchloride; aromatic biimidazoles such as 2-(2-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(2-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(2-fluorophenyl)-4,5-diphenylimidazole dimer, and 2-(2- or 4-methoxyphenyl)-4,5-diphenylimidazole dimer; and acylphosphine oxide derivatives such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. The photopolymerization initiator may be used alone or in combination of two or more. Among these, oxime derivatives are preferred from the viewpoint of not containing metal elements and being highly reactive and sensitive.

[0115] The amount of photopolymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass, and even more preferably 2 to 12 parts by mass, per 100 parts by mass of polyimide precursor.

[0116] The photopolymer is obtained by exposing a photosensitive resin composition comprising the polyimide precursor of the present disclosure, a photopolymerization initiator, and other optional components as needed. Examples of active light rays to be irradiated include ultraviolet light such as i-rays, visible light, and radiation, with i-rays being preferred. Exposure equipment can include parallel exposure machines, aligners, projection exposure machines, steppers, scanner exposure machines, and the like.

[0117] A photosensitive resin composition applied to a substrate may be subjected to pattern exposure via a photomask or the like. After exposure, a patterned resin film (patterned resin film) can be obtained by developing the material. Generally, when a negative-type photosensitive resin composition is used, unexposed areas are removed with a developer. As the developer, a good solvent for the photosensitive resin film can be used alone, or a good solvent and a poor solvent can be used in appropriate mixtures.

[0118] A cured product can be obtained by heat-treating the photopolymer. The polyimide precursor undergoes a dehydration and ring-closing reaction during the heat treatment process, becoming a polyimide resin.

[0119] The heat treatment temperature is preferably 380°C or lower, more preferably 250°C to 350°C, and even more preferably 270°C to 320°C. By keeping the heat treatment temperature within the above range, damage to the substrate or device can be minimized, enabling high-yield device production and energy savings in the process.

[0120] The heat treatment time is preferably 5 hours or less, and more preferably 30 minutes to 3 hours. By keeping the heat treatment time within the above range, the crosslinking reaction or the dehydration ring-closing reaction can proceed sufficiently. The heat treatment can be performed in the atmosphere of air or in an inert atmosphere such as nitrogen, but from the viewpoint of preventing oxidation of the pattern resin film, a nitrogen atmosphere is preferred.

[0121] Examples of equipment used for heat treatment include quartz tube furnaces, hot plates, rapid thermal annealing, vertical diffusion furnaces, infrared curing furnaces, electron beam curing furnaces, and microwave curing furnaces.

[0122] The cured product can be used as an interlayer insulating film, a cover coat layer, a surface protective film, etc. 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 passivation film, buffer coat film, interlayer insulating film, cover coat layer, and surface protective film, highly reliable electronic components such as semiconductor devices, multilayer wiring boards, various electronic devices, and multilayer devices such as multi-die fan-out wafer-level packages can be manufactured. [Examples]

[0123] The embodiments of the present disclosure will now be described in detail with reference to examples, but the embodiments of the present disclosure are not limited to these examples.

[0124] [Synthesis of pyromellitic acid-2-hydroxyethyl methacrylate diester] In a 0.5-liter poly bottle, 35.7 g (164 mmol) of pyromellitic dianhydride dried in a 160°C oven for 24 hours, 45.0 g (346.1 mmol) of 2-hydroxyethyl methacrylate, and 0.18 g (1.6 mmol) of hydroquinone were dissolved in 387.9 g of N-methyl-2-pyrrolidone. After adding 0.25 g (1.6 mmol) of 1,8-diazabicyclo[5.4.0]undeca-7-ene, the mixture was stirred at room temperature (25°C) for 24 hours to carry out esterification, thereby obtaining a pyromellitic-2-hydroxyethyl methacrylate diester solution. This solution was designated as the PMDA (HEMA) solution.

[0125] [Synthesis of 4,4'-oxydiphthalate-2-hydroxyethyl methacrylate diester] In a 0.5-liter poly bottle, 50.9 g (164 mmol) of 4,4'-oxydiphthalic acid dianhydride, dried in a 160°C oven for 24 hours, 45.0 g (346.1 mmol) of 2-hydroxyethyl methacrylate, and 0.18 g (1.6 mmol) of hydroquinone were dissolved in 387.9 g of N-methyl-2-pyrrolidone. After adding 0.75 g (4.9 mmol) of 1,8-diazabicyclo[5.4.0]undeca-7-ene, the mixture was stirred at room temperature (25°C) for 48 hours to carry out esterification, obtaining a solution of 4,4'-oxydiphthalic acid-2-hydroxyethyl methacrylate diester. This solution was designated as the ODPA (HEMA) solution.

[0126] [Halogenation (acid chloride formation)] 195.6 g of the PMDA(HEMA) solution and 58.6 g of the ODPA(HEMA) solution obtained above were placed in a 0.5 liter flask equipped with a stirrer and thermometer. Then, 25.1 g of thionyl chloride was added dropwise using a dropping funnel under ice cooling, ensuring that the reaction solution temperature was kept below 10°C. After the addition of thionyl chloride was complete, the reaction was carried out under ice cooling for 2 hours to obtain solutions of PMDA(HEMA) and ODPA(HEMA) acid chlorides.

[0127] [Synthesis of polyimide precursors (polyamic acid esters)] Using the obtained solutions of PMDA(HEMA) and ODPA(HEMA) acid chlorides, polyamic acid esters were synthesized by the following method.

[0128] Using a dropping funnel, a solution of 83.0 g of N-methyl-2-pyrrolidone containing 29.2 g (91.0 mmol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 32.5 g (410.1 mmol) of pyridine, and 0.07 g (0.6 mmol) of hydroquinone was added dropwise to 280.7 g of a solution of PMDA (HEMA) and ODPA (HEMA) acid chlorides, taking care to keep the reaction solution temperature below 10°C by ice cooling, to obtain a polyimide precursor solution.

[0129] [Purification of polyimide precursors (polyamic acid esters)] 1.0 g of the obtained polyimide precursor solution was mixed with 2.0 g of water, and then 10 g of each solvent shown in Table 1 was added, and the mixture was allowed to stand for 30 minutes. The visual appearance of the solution during standing is shown in Table 1.

[0130] [Table 1]

[0131] From the results in Table 1 above, it was found that the polyimide precursor was dissolved in the added solvent, and that the purification of the polyimide precursor was possible.

[0132] On the other hand, assuming a drying step as described in prior art 1, the synthesized polyimide precursor solution was heated at 40°C to 70°C for 24 hours. The molecular weight of the heated polyimide precursor was measured. The molecular weight was measured by the following method.

[0133] Using a gel permeation chromatography (GPC) system (Shimadzu Corporation), polyamide precursors were eluted using a TMF / DMF = 50 / 50 (volume basis), 0.06 M H3PO4, and a 0.03 M LiBr / H2O eluent. The molecular weight elution rate was measured from the elution time of the polystyrene sample.

[0134] The molecular weight measurement results are shown in Table 2. [Table 2]

[0135] As shown in Table 2, it was found that the molecular weight can increase during the drying process. Therefore, it can be seen that the increase in molecular weight due to drying can be suppressed by a purification method in which a solvent is added to a water-containing solution containing the polyimide precursor and redissolved without going through the drying process.

[0136] [Effects of purification on polyimide precursors] Water was added to the polyimide precursor solution obtained in the above synthesis, and then acetone was added to prepare a resolving solution. In this resolving solution, the amount of acetone relative to water (acetone / water, by volume) was 4.5, and the solid content concentration of the polyimide precursor was 5.3% by mass. After allowing this resolving solution to stand for 30 minutes, water four times the total volume of the resolving solution (by volume) was added to recrystallize the polyimide precursor, and the precipitated polyimide precursor was filtered.

[0137] The chlorine content (mass ppm), esterification rate (%), NMP content (mass %), weight-average molecular weight (Mw), number-average molecular weight (Mn), and dispersion (Mw / Mn) of the polyimide precursor before and after purification were measured using the following method. The results are shown in Table 5.

[0138] (Measurement of chlorine content) The measurement was performed using potentiometric titration (silver nitrate titration) with an automatic titrator (HIRANUMA Co., Ltd., COM-1700S). First, approximately 0.2 g of polyimide precursor powder was weighed into a 100 mL poly cup and dissolved in approximately 50 g of γ-butyrolactone. After adding 0.53 ± 0.03 g of dilute nitric acid to the polymer solution, the measurement was performed. After the measurement, the concentration was converted to the concentration in the polyimide precursor powder by multiplying by the dilution factor.

[0139] (Measurement of esterification rate and NMP content) The esterification rate and NMP content are as follows: 1 The peaks were determined from the 1H-NMR spectrum. The measurement conditions were as follows:

[0140] [Table 3]

[0141] The NMP content (mass %) in the polyimide precursor was calculated from the integral value of the methyl group (2.7 ppm) of NMP. NMP content [mass%] = NMP peak integral value × 5.287 + 5 × 10 -5

[0142] Furthermore, the esterification rate was determined from the ratio of the integral values ​​of the methylene protons (4.2 ppm to 4.7 ppm) and aromatic protons (7.0 ppm to 8.8 ppm) of 2-hydroxyethyl methacrylate on the side chain of the polyimide precursor, and the theoretical ratio when the esterification rate is 100%.

[0143] (Measurement of molecular weight) The molecular weight of the polymer was calculated using the GPC method from a calibration curve based on polystyrene standards. The measurement conditions were as follows:

[0144] [Table 4]

[0145] [Table 5]

[0146] As shown in Table 5, it was found that there were no significant changes in weight-average molecular weight (Mw), dispersion (Mw / Mn), and esterification rate (%) before and after purification. Furthermore, it was found that the chlorine content was dramatically reduced, and the content of NMP used as a reaction solvent in the synthesis was also reduced.

[0147] [Effects of pH] A 500 mL resolving solution was prepared containing acetone and water in a 1 / 3 ratio (acetone / water) by volume, and the solid content concentration of the polyimide precursor was 10% by mass. Acetic acid was added to this resolving solution to adjust the pH to 2.8, thus preparing resolving solution 1. After allowing resolving solution 1 to stand for 30 minutes, four times the total volume (by volume) of water was added to recrystallize the polyimide precursor, and the precipitated polyimide precursor was filtered using a suction filter. The filtration time was 5 minutes. On the other hand, a second re-dissolution solution was prepared by adding ammonia to the original re-dissolution solution before pH adjustment to adjust the pH to 5.8. Recrystallization and filtration were performed in the same manner as with re-dissolution solution 1, except that re-dissolution solution 2 was used, and the filtration time was 1.5 hours or more.

Claims

1. A step of preparing a water-containing solution containing water and a polyimide precursor, A step of adding a solvent other than water to the water-containing liquid to dissolve the polyimide precursor in the solvent, Includes, The polyimide precursor has polymerizable unsaturated bonds, A method for producing a polyimide precursor, wherein the solvent is at least one selected from the group consisting of acetone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl lactate, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, methyl sulfoxide, isopropanol, γ-butyrolactone, and methyl ethyl ketone.

2. A step of preparing a water-containing solution comprising water and a polyimide precursor, A step of adding a solvent other than water to the water-containing liquid to dissolve the polyimide precursor in the solvent, Includes, The polyimide precursor has polymerizable unsaturated bonds, The solubility parameter of the aforementioned solvent is 20 MPa １／２ ~25 MPa １／２ A method for producing a polyimide precursor.

3. A method for producing a polyimide precursor according to claim 1 or claim 2, wherein the polyimide precursor has a structural unit represented by the following general formula (1). 【Chemistry 1】 (In general formula (1), X represents a tetravalent organic group and Y represents a divalent organic group. R １ and R ２ Each of these is independently a hydrogen atom, a group represented by the following general formula (2), or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and R １ and R ２ At least one of them is a group represented by the following general formula (2). 【Chemistry 2】 (In general formula (2), R ３ ~R ５ Each of these independently represents a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and q represents an integer from 1 to 10.

4. A method for producing a polyimide precursor according to any one of claims 1 to 3, wherein the ratio of the amount of the solvent to the total amount of the polyimide precursor and the solvent is 50% by mass or more.

5. A method for producing a polyimide precursor according to any one of claims 1 to 4, wherein the ratio of the amount of the solvent to the total amount of the polyimide precursor and the solvent is 95% by mass or less.

6. A method for producing a polyimide precursor according to any one of claims 1 to 5, wherein the ratio of the amount of water to the total amount of the polyimide precursor and the water in the water-containing liquid is 50% by mass or more.

7. A method for producing a polyimide precursor according to any one of claims 1 to 6, wherein the ratio of the amount of water to the total amount of the polyimide precursor and the water in the water-containing liquid is 75% by mass or less.

8. Before the step of preparing the aforementioned water-containing liquid, A method for producing a polyimide precursor according to any one of claims 1 to 7, further comprising the step of reacting a carboxylic acid halide with an amine compound to obtain a polyimide precursor.

9. A method for producing a polyimide precursor includes the steps of: preparing a water-containing solution containing water and a polyimide precursor; and adding a solvent other than water to the water-containing solution to dissolve the polyimide precursor in the solvent; A step of reacting the polyimide precursor with a photopolymerization initiator to obtain a photopolymerized product, The process of heating the photopolymerized product, Includes, A method for producing a cured product, wherein the solvent is at least one selected from the group consisting of acetone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl lactate, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, methyl sulfoxide, isopropanol, γ-butyrolactone, and methyl ethyl ketone.

10. A method for producing a polyimide precursor includes the steps of: preparing a water-containing solution containing water and a polyimide precursor; and adding a solvent other than water to the water-containing solution to dissolve the polyimide precursor in the solvent; A step of reacting the polyimide precursor with a photopolymerization initiator to obtain a photopolymerized product, The process of heating the photopolymerized product, Includes, A method for producing a cured product, wherein the solubility parameter of the solvent is 20 MPa 1 / 2 to 25 MPa 1 / 2.

11. A process to obtain a polyimide precursor by the manufacturing method described in any one of claims 1 to 8. To what extent, A step of reacting the polyimide precursor with a photopolymerization initiator to obtain a photopolymerized product, The process of heating the photopolymerized product, A method for producing a cured product containing [the specified ingredient].

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