Photosensitive polyimide resin composition, resin film, and electronic device

Abstract

A photosensitive polyimide resin composition, according to the present invention, contains a closed-ring polyimide resin (A) having the structure shown in formula (1) below and a polyfunctional radical polymerizable compound (B) having radical polymerizable functional groups and oxyalkylene groups, wherein the number of the radical polymerizable functional groups in the polyfunctional radical polymerizable compound (B) is 3-100, inclusive, and the total number of added moles of the oxyalkylene groups in the polyfunctional radical polymerizable compound (B) is 5-100, inclusive.

Description

[Technical Field]

[0001] The present invention relates to a photosensitive polyimide resin composition, a resin film, and an electronic device. [Background technology]

[0002] As insulating films for electronic devices, resin films obtained by exposing a photosensitive polyimide resin composition, which has excellent heat resistance and insulating properties, are widely used. Examples of technologies relating to such photosensitive polyimide resin compositions include those described in Patent Documents 1 and 2.

[0003] Patent Document 1 describes a photosensitive polyimide composition that includes a photosensitive polyimide obtained by reacting a first polyimide having a ring-closed imide structure with an isocyanate compound having a carbon-carbon double bond. Patent Document 2 describes a photosensitive resin composition containing polyimides, polybenzoxazoles, polyamideimides having alkoxymethyl groups or methylol groups, precursors thereof or copolymers thereof, and compounds having at least two alkoxymethyl groups or methylol groups. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-147761 [Patent Document 2] Japanese Patent Publication No. 2010-229210 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In recent years, the demand for miniaturization and improved performance of electronic devices has been increasing, and there is a growing need for the development of photosensitive resin compositions that can form resists with high film thickness. Here, according to the study by the present inventors, it has been clarified that there is room for improvement in terms of flexibility when a photosensitive polyimide resin composition using a conventional closed-ring polyimide resin is made into a thick film.

[0006] The present invention has been made in view of the above circumstances, and provides a photosensitive polyimide resin composition excellent in the balance between thick film heat resistance and thick film flexibility.

Means for Solving the Problems

[0007] The present inventors have intensively studied to solve the above problems. As a result, by combining a closed-ring polyimide resin (A) having a specific structure and a polyfunctional radically polymerizable compound (B) having 3 or more and 100 or less radically polymerizable functional groups and an oxyalkylene group having a total addition molar number of 5 or more and 100 or less, it has been found that the balance between thick film heat resistance and thick film flexibility of the photosensitive polyimide resin composition can be improved, and the present invention has been completed.

[0008] That is, according to the present invention, there are provided a photosensitive polyimide resin composition, a resin film, and an electronic device shown below.

[0009] [1] A photosensitive polyimide resin composition containing a closed-ring polyimide resin (A) having a structure represented by the following formula (1) and a polyfunctional radically polymerizable compound (B) having a radically polymerizable functional group and an oxyalkylene group, where the number of the radically polymerizable functional groups in the polyfunctional radically polymerizable compound (B) is 3 or more and 100 or less, and the total addition molar number of the oxyalkylene groups in the polyfunctional radically polymerizable compound (B) is 5 or more and 100 or less.

Chemical Formula

[10] The above photosensitive polyimide resin composition was pre-baked at 100°C for 5 minutes, and then exposed to light from a high-pressure mercury lamp with wavelengths less than 365 nm filtered out at a density of 250 mJ / cm². 2 More than 5,000mJ / cm 2 A photosensitive polyimide resin composition according to any of [1] to [9] above, wherein the glass transition temperature of a resin film with a thickness of 30 μm obtained by irradiating with an optimal exposure dose within the following range and then heat-treating it under conditions of 200°C for 2 hours in a nitrogen atmosphere is 180°C or higher.

[11] A photosensitive polyimide resin composition according to any one of [1] to

[10] above, wherein the light transmittance at a wavelength of 365 nm is 80% or more when the above-mentioned ring-closed polyimide resin (A) is prepared as a 3% by mass solid content solution.

[12] A photosensitive polyimide resin composition according to any one of [1] to

[11] above, wherein A in formula (1) above contains an aromatic ring as an aromatic hydrocarbon group.

[13] A photosensitive polyimide resin composition according to any one of [1] to

[12] above, wherein A in formula (1) above comprises at least one selected from the group consisting of the structures shown below. [ka] [In the formula, * indicates a bond.]

[14] The photosensitive polyimide resin composition according to any one of [1] to

[13] above, wherein the above-mentioned ring-closed polyimide resin (A) contains at least one unit composed of 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 4,4'-oxybis[3-(trifluoromethyl)benzeneamine], or 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene.

[15] A photosensitive polyimide resin composition according to any one of the above [1] to

[14] , further comprising at least one selected from the group consisting of a photopolymerization initiator, a solvent, an adhesion improver, a surface modifier, and a sensitizer.

[16] A photosensitive polyimide resin composition according to any of the above [1] to

[15] , for forming an insulating film.

[17] A resin film comprising a photosensitive polyimide resin composition described in any of the above [1] to

[16] or a cured product of the above photosensitive polyimide resin composition.

[18] The resin film described in

[17] above, having a film thickness of 20 μm or more.

[19] An electronic device comprising the resin film described above

[18] . [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a photosensitive polyimide resin composition that exhibits an excellent balance between thick-film heat resistance and thick-film flexibility. [Modes for carrying out the invention]

[0011] A description in detail will be given of an embodiment for carrying out the present invention (hereinafter simply referred to as "this embodiment"). The following embodiment is illustrative for explaining the present invention and does not limit the content of the present invention. The present invention can be carried out by modifying it as appropriate within the scope of its gist. In this embodiment, the provisions that are considered preferred can be adopted arbitrarily, and combinations of preferred provisions are considered more preferred. In this embodiment, the description "XX~YY" means "XX or more and YY or less".

[0012] In this embodiment, "(meth)acrylate" means both "acrylate" and "methacrylate." The same applies to other similar terms ("(meth)acrylic acid," "(meth)acryloyl group," etc.).

[0013] 1. Photosensitive polyimide resin composition The photosensitive polyimide resin composition according to this embodiment comprises a pre-closed ring polyimide resin (A) having a structure represented by the following formula (1), and a polyfunctional radical polymerizable compound (B) having radical polymerizable functional groups and oxyalkylene groups, wherein the number of radical polymerizable functional groups in the polyfunctional radical polymerizable compound (B) is 3 to 100, and the total number of moles of oxyalkylene groups added in the polyfunctional radical polymerizable compound (B) is 5 to 100.

[0014] [ka] In formula (1) above, R is a tetravalent group having 4 to 10 carbon atoms and having a cyclic structure, an acyclic structure, or both a cyclic and an acyclic structure. A is a divalent group having 2 to 39 carbon atoms and having at least one group selected from the group consisting of aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and organosiloxane groups. The main chain of A may contain at least one group selected from the group consisting of -O-, -SO2-, -CO-, -CH2-, -C(CH3)2-, -C2H4O-, and -S-. n indicates the number of repeating units. The end of formula (1) above is either a group represented by formula (2) or formula (3) below, or a hydrogen atom, and at least one of the ends is a group represented by formula (2) or formula (3) below.

[0015] [ka] In the above formulas (2) and (3), X and X 2 Each of these groups is independently a group having 2 to 15 carbon atoms and may have at least one group selected from the group consisting of ester bonds and double bonds. 2 Each of these is independently either a hydrogen atom or a methyl group.

[0016] The photosensitive polyimide resin composition according to this embodiment contains a pre-closed ring polyimide resin (A) having the structure shown in formula (1) above, and a polyfunctional radical polymerizable compound (B) having 3 to 100 radical polymerizable functional groups and oxyalkylene groups with a total number of added moles of 5 to 100, and is a composition with an excellent balance of thick film heat resistance and thick film flexibility. Furthermore, because the photosensitive polyimide resin composition according to this embodiment has an excellent balance of thick film heat resistance and thick film flexibility, it can effectively suppress the occurrence of cracks, chips, tears, etc. in the resulting resin film.

[0017] In this embodiment, "excellent thick-film heat resistance" means that the glass transition temperature is high when the resin film thickness is, for example, 20 μm or more. In this embodiment, "excellent thick-film flexibility" means that the elongation at break is high when the resin film thickness is, for example, 20 μm or more.

[0018] The photosensitive polyimide resin composition according to this embodiment contains a pre-closed ring polyimide resin (A) having the structure shown in formula (1) above, and a polyfunctional radical polymerizable compound (B) having 3 to 100 radical polymerizable functional groups and oxyalkylene groups with a total number of added moles of 5 to 100, thereby exhibiting an excellent balance between thick-film heat resistance and thick-film flexibility. The reason for this is not entirely clear, but it is thought to be as follows. First, the pre-closed ring polyimide resin (A) having the structure shown in formula (1) above has excellent transparency, so even if the resin film is thick, the light during exposure can easily reach the bottom of the film, allowing for more uniform crosslinking of the resin film, resulting in excellent thick-film curing properties. Furthermore, by combining it with a polyfunctional radical polymerizable compound (B), the crosslinking density of the resin film can be improved, and the heat resistance of the thick film can be enhanced. Furthermore, since the pre-closed ring polyimide resin (A) is a resin in which imidization is already completed, a dehydration and ring-closing step is unnecessary. Therefore, by combining it with a polyfunctional radical polymerizable compound (B) having an oxyalkylene group, it is thought that curing shrinkage of the resin film during exposure can be suppressed and the flexibility of the thick film can be improved. Here, while the flexibility of the resulting resin film can be improved by using a polyfunctional radical polymerizable compound having an oxyalkylene group, the heat resistance of the resin film tends to decrease. However, by using a polyfunctional radical polymerizable compound (B) in which the radical polymerizable functional group and the total number of added moles are within the above range, the crosslinked structure of the resulting resin film will be a well-balanced structure in terms of achieving both heat resistance and flexibility, and it is thought that the flexibility can be improved while suppressing the decrease in the heat resistance of the resin film. From the above, according to the photosensitive polyimide resin composition according to this embodiment, it is considered that by combining the ring-closed polyimide resin (A) and the polyfunctional radical polymerizable compound (B), the balance between the thick film heat resistance and the thick film flexibility can be improved.

[0019] [Ring-closed polyimide resin (A)] The ring-closed polyimide resin (A) according to this embodiment has a structure represented by the following formula (1).

[0020] [Chemical formula] In the above formula (1), R is a tetravalent group having 4 to 10 carbon atoms with a cyclic structure, an acyclic structure, or both a cyclic structure and an acyclic structure. A is a divalent group having at least one group selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and an organosiloxane group, and having 2 to 39 carbon atoms. At least one group selected from the group consisting of -O-, -SO2-, -CO-, -CH2-, -C(CH3)2-, -C2H4O-, and -S- may be interposed in the main chain of A. n represents the number of repeating units. The terminal of the above formula (1) is either a group represented by the following formula (2) or formula (3), or a hydrogen atom, and at least one of the terminals is a group represented by the following formula (2) or formula (3).

[0021] [Chemical formula] In the above formulas (2) and (3), X and X 2 are each independently a group having 2 to 15 carbon atoms, and may have at least one group selected from the group consisting of an ester bond and a double bond. Y and Y 2 are each independently a hydrogen atom or a methyl group.

[0022] Preferably, R in formula (1) above has at least a cyclic structure, and examples of such cyclic structures include tetravalent groups formed by removing four hydrogen atoms from cyclohexane, cyclopentane, cyclobutane, bicyclopentane, and their stereoisomers. More specifically, examples of such tetravalent groups include groups represented by the following structural formula.

[0023] [ka] [In the formula, * indicates a bond.]

[0024] Among the above, the tetravalent group formed by removing four hydrogen atoms from cyclohexane is preferred.

[0025] In formula (1) above, A is a divalent group having 2 to 39 carbon atoms and having at least one group selected from the group consisting of aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and organosiloxane groups. The main chain of A may contain at least one group selected from the group consisting of -O-, -SO2-, -CO-, -CH2-, -C(CH3)2-, -C2H4O-, and -S-.

[0026] More specifically, A includes cyclohexane, dicyclohexylmethane, dimethylcyclohexane, isophorone, norbornane and their alkyl-substituted derivatives, as well as their halogen-substituted derivatives; benzene, naphthalene, biphenyl, diphenylmethane, diphenyl ether, diphenyl sulfone, benzophenone and their alkyl-substituted derivatives, as well as their halogen-substituted derivatives; and divalent groups formed by removing two hydrogen atoms from compounds such as organo(poly)siloxanes. A preferably has a cyclic structure, and more preferably has at least one selected from alicyclic hydrocarbon groups and aromatic rings. It is even more preferable that A has an aromatic ring as an aromatic hydrocarbon group. More specifically, divalent groups with 6 to 27 carbon atoms represented by the following structural formula are preferred.

[0027] [ka] In the formula, * indicates a bond.

[0028] It is more preferable that the divalent group A, having 2 to 39 carbon atoms, includes at least one selected from the group consisting of the structures shown below.

[0029] [ka] In the formula, * indicates a bond.

[0030] It is even more preferable that the divalent group A, having 2 to 39 carbon atoms, includes at least one group (Ia) selected from the group consisting of the structures shown below.

[0031] [ka] In the formula, * indicates a bond.

[0032] It is even more preferable that the divalent group A, having 2 to 39 carbon atoms, includes at least one group (Ib) selected from the group consisting of the structures shown below.

[0033] [ka] In the formula, * indicates a bond.

[0034] The divalent group A, having 2 to 39 carbon atoms, is more preferably defined by the following formula (Ic).

[0035] [ka] [In the formula, * indicates a bond.]

[0036] In this embodiment, the pre-closed ring polyimide resin (A) preferably has a ratio of 60 mol% or more of at least one constituent unit selected from (Ia), (Ib), and (Ic) as A in formula (1) above, which is preferable from the viewpoint of solubility in a developer (hereinafter also simply referred to as "developer solubility").

[0037] In formula (1) above, the ratio of at least one constituent unit selected from (Ia), (Ib), and (Ic) in A is more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%. In particular, it is preferable to include the constituent unit derived from the diamine represented by formula (Ic) in the above ratio.

[0038] The value n, which represents the number of repeating units of the structural unit represented by formula (1) above, is preferably 5 or more, more preferably 10 or more, and even more preferably 15 or more, from the viewpoint of further improving the mechanical properties of the resulting resin film, and is preferably 250 or less, more preferably 200 or less, and even more preferably 150 or less, from the viewpoint of further improving the developer solubility of the resulting photosensitive polyimide resin composition.

[0039] The pre-closed ring polyimide resin (A) according to this embodiment has either a group represented by formula (2) or formula (3) or a hydrogen atom at one of its ends, and at least one of the ends is a group represented by formula (2) or formula (3). The pre-closed ring polyimide resin (A) may have one end with the structure represented by formula (2) or formula (3), or both ends may have the structure represented by formula (2) or formula (3). In formula (2) or formula (3) above, X or X 2 The group represented by is a group having 2 to 15 carbon atoms, and may have at least one group selected from the group consisting of ester bonds and double bonds. Y or Y 2 The group indicated by is either a hydrogen atom or a methyl group.

[0040] The structure represented by formula (2) or formula (3) above more specifically corresponds to a structure obtained by reacting the terminal amine of a polyimide resin with a functional group-containing compound. Examples of the functional group-containing compound include compounds having an isocyanate group or epoxy group and a (meth)acrylic group. Examples of such compounds include 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 1,1-bis(acryloyloxymethyl)ethyl isocyanate, glycidyl methacrylate, glycidyl acrylate, and allyl glycidyl ether. The structure represented by formula (2) or formula (3) above may have a structure obtained by reacting the compound with the amine terminal of the polyimide resin.

[0041] The weight-average molecular weight of the pre-closed ring polyimide resin (A) is preferably 70,000 or less, more preferably 60,000 or less, more preferably 50,000 or less, even more preferably 45,000 or less, even more preferably 40,000 or less, and even more preferably 35,000 or less, from the viewpoint of further improving the developer solubility and thick-film developability of the photosensitive polyimide resin composition, and preferably 5,000 or more, more preferably 10,000 or more, even more preferably 13,000 or more, and even more preferably 15,000 or more, from the viewpoint of further improving the mechanical properties of the resulting resin film. By having the weight-average molecular weight of the pre-closed ring polyimide resin (A) within the above range, developer solubility can be improved, the residual film rate in the unexposed areas can be further reduced, and the developability of the photosensitive polyimide resin composition can be further improved. Here, the weight-average molecular weight is the weight-average molecular weight on a polystyrene basis. The photosensitive polyimide resin composition according to this embodiment contains a pre-closed ring polyimide resin (A) having the structure shown in formula (1) above and a weight-average molecular weight of 70,000 or less, and a polyfunctional radical polymerizable compound (B) having 3 to 100 radical polymerizable functional groups and 5 to 100 oxyalkylene groups with a total number of added moles, thereby providing an excellent balance of thick-film developability, thick-film heat resistance, and thick-film flexibility. The reason why thick-film developability can be improved is not clear, but it is thought to be as follows. First, the greater the difference in developer solubility between the exposed and unexposed areas, the better the developability. Therefore, to improve developability, it is important to widen the difference in developer solubility between the exposed and unexposed areas. Here, the pre-closed ring polyimide resin (A), which has the structure shown in formula (1) above and a weight-average molecular weight of 70,000 or less, has high developer solubility, so it is considered that the developer solubility of the unexposed areas remains high even when the resin film is thickened. Furthermore, since the pre-closed ring polyimide resin (A) having the structure shown in formula (1) above has excellent transparency, even if the resin film is thick, light during exposure can easily reach the bottom of the film, allowing for more uniform crosslinking of the resin film. Moreover, by combining it with a polyfunctional radical polymerizable compound (B), the crosslinking density of the resin film can be improved, and the solubility of the developer in the exposed area can be reduced. From the above, it is considered that, according to the photosensitive polyimide resin composition of this embodiment, by combining a pre-closed ring polyimide resin (A) and a polyfunctional radical polymerizable compound (B), the difference in developer solubility between the exposed and unexposed areas can be increased, thereby improving the developability of thick films.

[0042] The pre-closed ring polyimide resin (A) can be obtained by reacting the diamine component described in detail below with the tetracarboxylic acid component.

[0043] <Diamine component> Examples of diamine components include diamines, diisocyanates, and diaminodisilanes, with diamines being preferred. The diamine content in the diamine component used as a raw material is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and preferably 100 mol% or less.

[0044] The above diamine may be either an aliphatic diamine or an aromatic diamine, or a mixture thereof. In this embodiment, "aromatic diamine" refers to a diamine in which the amino group is directly bonded to an aromatic ring, and which may include an aliphatic group, an alicyclic group, or other substituents in part of its structure. "Aliphatic diamine" refers to a diamine in which the amino group is directly bonded to an aliphatic group or an alicyclic group, and which may include an aromatic group or other substituents in part of its structure.

[0045] Generally, when aliphatic diamines are used as raw materials for polyimide resins, the polyamic acid and aliphatic diamine form a strong complex as an intermediate product, making it difficult to obtain high molecular weight polyimides. Therefore, it is necessary to use solvents with relatively high solubility of the complex, such as cresol. When cyclohexanetetracarboxylic acid, cyclobutanetetracarboxylic acid, or their derivatives are used as the tetracarboxylic acid component, a complex is formed in which the bond between the polyamic acid and the aliphatic diamine is relatively weak, making it easy to increase the molecular weight of the polyimide. Selecting a diamine with a fluorine substituent as a raw material is preferable because it results in a polyimide resin with excellent transparency.

[0046] Examples of the above-mentioned aliphatic diamines include 4,4'-diaminodicyclohexylmethane, ethylenediamine, hexamethylenediamine, polyethylene glycol bis(3-aminopropyl) ether, polypropylene glycol bis(3-aminopropyl) ether, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, m-xylylenediamine, p-xylylenediamine, isophoronediamine, norbornanediamine, and siloxanediamines.

[0047] Examples of the above aromatic diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, m-phenylenediamine, p-phenylenediamine, diaminobenzophenone, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-oxybis[3-(trifluoromethyl)benzeneamine], 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, and 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0048] The above diamine component preferably includes at least one selected from 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 4,4'-oxybis[3-(trifluoromethyl)benzeneamine], and 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene. By including at least these diamines as diamine components, the light transmittance and developer solubility of the resulting photosensitive polyimide resin composition at specific wavelengths can be further improved. As a result, the curability of the exposed areas can be improved, and the residual film rate in the unexposed areas can be reduced, thereby further improving the developability of the resulting photosensitive polyimide resin composition. The pre-ring closed polyimide resin (A) according to this embodiment preferably contains at least one unit composed of 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 4,4'-oxybis[3-(trifluoromethyl)benzeneamine], or 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene.

[0049] <Tetracarboxylic acid component> Examples of tetracarboxylic acid components include cyclohexanetetracarboxylic acid, cyclohexanetetracarboxylic acid esters, cyclohexanetetracarboxylic acid dianhydride, cyclobutanetetracarboxylic acid, cyclobutanetetracarboxylic acid esters, cyclobutanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid, cyclopentanetetracarboxylic acid esters, cyclopentanetetracarboxylic acid dianhydride, and bicyclopentanetetracarboxylic acid dianhydride. Among these, the tetracarboxylic acid component preferably contains at least one selected from cyclohexanetetracarboxylic acid dianhydride, cyclobutanetetracarboxylic acid dianhydride, and cyclopentanetetracarboxylic acid dianhydride, and more preferably contains cyclohexanetetracarboxylic acid dianhydride. The above-mentioned tetracarboxylic acid components include positional isomers.

[0050] More preferred specific examples of the above tetracarboxylic acid components include 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid methyl ester, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-butanetetracarboxylic acid methyl ester, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid methyl ester, and 1,2,4,5-cyclopentanetetracarboxylic acid. Examples include 1,2,4,5-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclopentanetetracarboxylic acid methyl ester, 3-carboxymethyl-1,2,4-cyclopentanetricarboxylic acid, bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic acid, bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic acid methyl ester, dicyclohexyltetracarboxylic acid, dicyclohexyltetracarboxylic acid dianhydride, and dicyclohexyltetracarboxylic acid methyl ester. Among these, the tetracarboxylic acid component is preferably selected from 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, and 1,2,4,5-cyclohexanetetracarboxylic acid methyl ester, as it is advantageous in that it is easy to increase the molecular weight when producing polyimide resin and a flexible resin film can be easily obtained.

[0051] The tetracarboxylic acid component may include other tetracarboxylic acids or their derivatives, for example, to the extent that they do not impair the flexibility or thermocompression properties of the resin film. Examples of these other tetracarboxylic acids or their derivatives include pyromellitic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, 2,2-bis(3,4-dicarboxyphenyl)propane, 2,2-bis(2,3-dicarboxyphenyl)propane, 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane, 2,2-bis(2,3-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane, bis(3,4-dicarboxyphenyl)sulfone, and bi At least one can be selected from s(3,4-dicarboxyphenyl) ether, bis(2,3-dicarboxyphenyl) ether, 3,3',4,4'-benzophenonetetracarboxylic acid, 2,2',3,3'-benzophenonetetracarboxylic acid, 4,4-(p-phenylenedioxy)diphthalic acid, 4,4-(m-phenylenedioxy)diphthalic acid, ethylenetetracarboxylic acid, 1,1-bis(2,3-dicarboxyphenyl)ethane, bis(2,3-dicarboxyphenyl)methane, bis(3,4-dicarboxyphenyl)methane, and derivatives thereof.

[0052] The light transmittance at a wavelength of 365 nm of the pre-closed ring polyimide resin (A) according to this embodiment, when prepared as a 3% by mass solids solution, is preferably 80% or more, more preferably 85% or more, even more preferably 88% or more, and even more preferably 90% or more, from the viewpoint of more uniformly crosslinking the resin film and further improving thick film curability and thick film patterning properties.

[0053] <Method for producing ring-closed polyimide resin (A)> The pre-closed ring polyimide resin (A) according to this embodiment can be obtained, for example, by a manufacturing method comprising the following steps (1) and (2). Step (1): A tetracarboxylic acid component and a diamine component are reacted to obtain a polyimide resin having an amino group at the end. Step (2): The polyimide resin having an amino group at its end obtained in step (1) is reacted with the functional group-containing compound (a compound having an isocyanate group or epoxy group and a (meth)acrylic group).

[0054] (Process (1)) In step (1), a tetracarboxylic acid is reacted with a diamine component to obtain a polyimide resin having an amino group at its terminus. The organic solvent used when reacting the tetracarboxylic acid component with the diamine component is not particularly limited, but an organic solvent containing at least one selected from the group consisting of cyclic ethers, cyclic ketones, cyclic esters, amides, and ureas is preferred. Specific examples of preferred solvents are not particularly limited, but at least one selected from the group consisting of aprotic polar organic solvents such as γ-butyrolactone, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, hexamethylphosphoramide, cyclopentanone, cyclohexanone, 1,3-dioxolane, 1,4-dioxane, tetramethylurea, and tetrahydrofuran is preferred. Among these, it is more preferable that one or more are selected from the group consisting of γ-butyrolactone, N,N-dimethylacetamide, N,N-dimethylformamide, and N-methyl-2-pyrrolidone.

[0055] An imidation catalyst can be used when reacting the tetracarboxylic acid component with the diamine component in step (1). A tertiary amine compound is preferred as the imidation catalyst, and specifically, at least one selected from the group consisting of trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, triethylenediamine, N-methylpyrrolidine, N-ethylpyrrolidine, N-methylpiperidine, N-ethylpiperidine, imidazole, pyridine, quinoline, and isoquinoline can be used.

[0056] The reaction temperature in step (1) is, for example, in the range of 160°C to 230°C, preferably in the range of 170°C to 210°C, and more preferably in the range of 180°C to 200°C. If the reaction temperature in step (1) is above the lower limit, imidization and molecular weight increase can be carried out more effectively. If the reaction temperature in step (1) is below the upper limit, the solution viscosity can be maintained more appropriately, and problems such as the resin sticking to the walls of the reaction vessel can be further avoided. In some cases, an azeotropic dehydrating agent such as toluene or xylene may be used. The reaction pressure is usually atmospheric pressure, but the reaction can be carried out under pressure if necessary. The holding time of the reaction temperature is preferably 1 hour or more, and more preferably 3 hours or more. If the holding time of the reaction temperature is above the lower limit, imidization and molecular weight increase can be carried out more effectively. There is no particular upper limit to the reaction time, but it can be carried out in the range of, for example, 10 hours or less.

[0057] In step (1), it is preferable to react the tetracarboxylic acid component "A moles" and the diamine component "B moles" in the range of 0.80 ≤ A / B ≤ 0.99, and more preferably in the range of 0.85 ≤ A / B ≤ 0.97. By setting A / B ≤ 0.99, it is possible to have an excess of diamine at the ends of the polyimide, thereby obtaining a polyimide resin having amino groups at the ends and a molecular weight that has sufficient developer solubility. If A / B is ≤ 0.80, a polyimide resin with a molecular weight that exhibits sufficient flexibility can be obtained. As the A / B ratio approaches 1.0, a higher molecular weight polyimide resin can be obtained. Therefore, by appropriately adjusting the A / B ratio, a polyimide resin with the desired molecular weight can be obtained.

[0058] <Process (2)> Step (2) is a step to modify the ends of the polyimide resin obtained in step (1). Specifically, as described above, the polyimide is reacted with the functional group-containing compound (a compound having an isocyanate group or epoxy group and a (meth)acrylic group) to obtain a polyimide resin having (meth)acrylic groups at its ends.

[0059] Functional group-containing compounds that modify the ends of polyimide resins are compounds having an isocyanate group or epoxy group and a (meth)acrylic group. Specifically, examples include 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl acrylate, 1,1-bis(acryloyloxymethyl)ethyl isocyanate, glycidyl methacrylate, glycidyl acrylate, and allyl glycidyl ether. These functional group-containing compounds may be used individually or in combination of two or more types. It is preferable to use the functional group-containing compounds in a ratio of 0.1 to 30 molar times with respect to the polyimide resin having amino groups at its ends.

[0060] The reaction temperature in step (2) is preferably in the range of 30°C to 100°C, and the reaction time is preferably 1 hour to 10 hours. When reacting the amino group terminus of a polyimide resin with the isocyanate or epoxy group of a functional group-containing compound, the reaction may be carried out directly or, if necessary, in the presence of a catalyst. Examples of catalysts include amine compounds such as triethylamine and organophosphorus compounds such as triphenylphosphine, which may be used individually or in combination of two or more. Polymerization inhibitors may be used to suppress side reactions during the reaction. Examples of polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, and methylhydroquinone, which may be used individually or in combination of two or more.

[0061] The content of the pre-closed ring polyimide resin (A) in the photosensitive polyimide resin composition according to this embodiment is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less, when the total solid content of the photosensitive polyimide resin composition is 100% by mass, from the viewpoint of further improving the thick film patterning properties. In this embodiment, the total solid content of the photosensitive polyimide resin composition refers to the components that remain as solids when the photosensitive polyimide resin composition is cured, and components that volatilize upon heating, such as solvents, are excluded. On the other hand, liquid components that are incorporated into the resin film when heated and cured are included in the total solid content.

[0062] [Polyfunctional radical polymerizable compound (B)] The polyfunctional radical polymerizable compound (B) according to this embodiment has 3 to 100 radical polymerizable functional groups and oxyalkylene groups with a total number of added moles of 5 to 100. In this embodiment, if the polyfunctional radical polymerizable compound (B) includes two or more polyfunctional radical polymerizable compounds with different numbers of radical polymerizable functional groups, the number of radical polymerizable functional groups in the polyfunctional radical polymerizable compound (B) can be determined by adopting the weighted average value of the number of radical polymerizable functional groups in each polyfunctional radical polymerizable compound. Furthermore, in this embodiment, if the polyfunctional radical polymerizable compound (B) includes two or more polyfunctional radical polymerizable compounds with different total moles of oxyalkylene groups added, the total moles of oxyalkylene groups added to the polyfunctional radical polymerizable compound (B) can be determined by the weighted average value of the total moles of oxyalkylene groups added to each polyfunctional radical polymerizable compound.

[0063] The number of radical polymerizable functional groups in the polyfunctional radical polymerizable compound (B) is between 3 and 100, but from the viewpoint of further improving the balance between thick film heat resistance and thick film flexibility, it is preferably 4 or more, more preferably 5 or more, even more preferably 6 or more, and preferably 50 or less, even more preferably 30 or less, even more preferably 15 or less, even more preferably 10 or less, even more preferably 8 or less, and even more preferably 7 or less. The total number of moles of oxyalkylene groups added to the polyfunctional radical polymerizable compound (B) is 5 or more and 100 or less, but from the viewpoint of further improving the balance between thick film heat resistance and thick film flexibility, it is preferably 6 or more, more preferably 8 or more, even more preferably 10 or more, and preferably 90 or less, even more preferably 80 or less, even more preferably 70 or less, and even more preferably 65 or less.

[0064] The oxyalkylene group of the polyfunctional radical polymerizable compound (B) preferably contains at least one selected from an oxyethylene group and an oxypropylene group, and more preferably contains an oxyethylene group, from the viewpoint of further improving the balance between thick film heat resistance and thick film flexibility.

[0065] The number-average molecular weight of the polyfunctional radical polymerizable compound (B) is preferably 500 or more, more preferably 600 or more, even more preferably 800 or more, even more preferably 1,000 or more, and preferably 10,000 or less, more preferably 8,000 or less, and even more preferably 5,000 or less, from the viewpoint of further improving the balance between thick film heat resistance and thick film flexibility.

[0066] Examples of the radical polymerizable functional groups mentioned above include (meth)acryloyl groups and vinyl groups, with (meth)acryloyl groups being preferred. Examples of polyfunctional radical polymerizable compounds that constitute polyfunctional radical polymerizable compound (B) include polypropylene glycol di(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, propoxy Pentaerythritol tri(meth)acrylate, ethoxylated tris-(2-(meth)acryloxyethyl) isocyanurate, propoxylated tris-(2-(meth)acryloxyethyl) isocyanurate, ethoxylated ditrimethylolpropanetetra(meth)acrylate, propoxylated ditrimethylolpropanetetra(meth)acrylate, ethoxylated ditrimethylolpropanepenta(meth)acrylate, propoxylated ditrimethylolpropanepenta(meth)acrylate Ethoxylated ditrimethylolpropane hexa(meth)acrylate, propoxylated ditrimethylolpropane hexa(meth)acrylate, ethoxylated dipentaerythritol penta(meth)acrylate, propoxylated dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, propoxylated dipentaerythritol hexa(meth)acrylate, ethoxylated tripentaerythritol (meth)acrylate, pro Examples include oxytripentaerythritol (meth)acrylate, ethoxylated glycerin (meth)acrylate, propoxylated glycerin (meth)acrylate, ethoxylated diglycerin (meth)acrylate, propoxylated diglycerin (meth)acrylate, ethoxylated triglycerin (meth)acrylate, propoxylated triglycerin (meth)acrylate, ethoxylated polyglycerin-based (meth)acrylate, and propoxylated polyglycerin-based (meth)acrylate. These polyfunctional radical polymerizable compounds may be used individually or in combination of two or more.Furthermore, these polyfunctional radical polymerizable compounds may be used individually to adjust the number of radical polymerizable functional groups and the total number of moles of oxyalkylene groups added within the above range, or two or more may be combined to adjust the number of radical polymerizable functional groups and the total number of moles of oxyalkylene groups added within the above range. Here, ethoxylated or propoxylated polyglycerin-based (meth)acrylates refer to compounds having a polyglycerin skeleton and (meth)acryloyl groups. Examples of ethoxylated or propoxylated polyglycerin-based (meth)acrylates include SA-TE6 and SA-TE60 manufactured by Sakamoto Pharmaceutical Co., Ltd.

[0067] The content of the polyfunctional radical polymerizable compound (B) in the photosensitive polyimide resin composition according to this embodiment is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, when the amount of pre-closed polyimide resin (A) contained in the photosensitive polyimide resin composition is 100 parts by mass, from the viewpoint of further improving the balance between thick film heat resistance and thick film flexibility, and preferably 100 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less, from the viewpoint of further improving the balance between thick film heat resistance and thick film flexibility while further suppressing stickiness of the thick film pattern.

[0068] [Other ingredients] The photosensitive polyimide resin composition according to this embodiment preferably further comprises, as other components besides the pre-closed ring polyimide resin (A) and the polyfunctional radical polymerizable compound (B), at least one selected from the group consisting of, for example, a photopolymerization initiator, a solvent, an adhesion improver, a surface modifier, and a sensitizer, and more preferably at least one selected from the group consisting of a photopolymerization initiator and a solvent.

[0069] (Photopolymerization initiator) The photopolymerization initiator is not particularly limited and known ones can be used. For example, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-methyl-1- Examples of photopolymerization initiators include (4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. These photopolymerization initiators may be used individually or in combination of two or more. The amount of photopolymerization initiator in the photosensitive polyimide resin composition according to this embodiment is, for example, 0.1 parts by mass or more and 10 parts by mass or less, when the amount of pre-closed polyimide resin (A) contained in the photosensitive polyimide resin composition is 100 parts by mass.

[0070] (solvent) From the viewpoint of solubility, aprotic polar solvents are preferred as solvents. Examples of solvents include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N-benzyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-acetyl-ε-caprolactam, dimethylimidazolidinone, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and γ-butyrolactone. These solvents may be used individually or in combination of two or more. To further improve coatability, solvents such as toluene, xylene, diethyl ketone, methoxybenzene, and cyclopentanone may be mixed in a range that does not adversely affect the solubility of the polymer. By using an appropriate solvent, the photosensitive polyimide resin composition according to this embodiment can be used in a solution (varnish) state, thereby improving film-forming properties.

[0071] (Adhesion enhancer) The adhesion enhancer is not particularly limited and known ones can be used, including silane coupling agents such as amino group-containing silane coupling agents, epoxy group-containing silane coupling agents, mercapto group-containing silane coupling agents, and (meth)acrylic group-containing silane coupling agents, as well as known coupling agents such as titanate coupling agents and aluminate coupling agents. Examples of coupling agents include KP-390, KA-1003, KBM-1003, KBE-1003, KBM-303, KBM-403, KBE-402, KBE-403, KBM-1403, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, KBM-602, KBM-603, KBE-603, KBM-903, KBE-903, KBE-9103, KBM-9103, KBM-573, KBM-575, KBM-6123, KBE-585, KBM-703, KBM-802, KBM-803, KBE-846, and KBE-9007 (all trade names; manufactured by Shin-Etsu Chemical Co., Ltd.). These can be used individually or in combination of two or more types. The amount of adhesion improver in the photosensitive polyimide resin composition according to this embodiment is, for example, 0.0005 parts by mass or more and 20 parts by mass or less, when the amount of pre-closed ring polyimide resin (A) contained in the photosensitive polyimide resin composition is 100 parts by mass.

[0072] (Surface modifier) The surface modifier is not particularly limited and any known type can be used. For example, various surface modifiers such as silicone-based, acrylic-based, fluorine-based, nonionic, cationic, and anionic surface modifiers can be used. These may be used individually or in combination of two or more types. The content of the surface modifier in the photosensitive polyimide resin composition according to this embodiment is, for example, 0.001 parts by mass or more and 20 parts by mass or less, when the amount of pre-closed ring polyimide resin (A) contained in the photosensitive polyimide resin composition is 100 parts by mass.

[0073] (Sensitizer) The sensitizer is not particularly limited, and known sensitizers can be used. For example, amino group-containing sensitizers can be cited, and compounds having an amino group and a phenyl group in the same molecule are preferably exemplified. More specifically, benzophenone compounds such as 4,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 2-aminobenzophenone, 4-aminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, and 3,4-diaminobenzophenone; 2-(p-dimethylaminophenyl)benzoxazole, 2-(p-diethylaminophenyl)benzoxazole, 2-(p-dimethylaminophenyl)benzo[4,5]benzoxazole, 2-(p-dimethylaminophenyl)benzo[6,7]benzoxazole, and 2,5-bis(p-diethylaminophenyl)-1,3,4-oxadiazole Examples of p-dialkylaminophenyl group-containing compounds include 2-(p-dimethylaminophenyl)benzothiazole, 2-(p-diethylaminophenyl)benzothiazole, 2-(p-dimethylaminophenyl)benzimidazole, 2-(p-diethylaminophenyl)benzimidazole, 2,5-bis(p-diethylaminophenyl)-1,3,4-thiadiazole, (p-dimethylaminophenyl)pyridine, (p-diethylaminophenyl)pyridine, (p-dimethylaminophenyl)quinoline, (p-diethylaminophenyl)quinoline, (p-dimethylaminophenyl)pyrimidine, and (p-diethylaminophenyl)pyrimidine. These sensitizers may be used alone or in combination of two or more. The amount of sensitizer in the photosensitive polyimide resin composition according to this embodiment is, for example, 0.001 parts by mass or more and 10 parts by mass or less, when the amount of pre-closed ring polyimide resin (A) contained in the photosensitive polyimide resin composition is 100 parts by mass.

[0074] When the photosensitive polyimide resin composition according to this embodiment is used to form a resin film with a thickness of 30 μm, the elongation at break is preferably 8% or more, more preferably 10% or more, even more preferably 12% or more, and even more preferably 15% or more, from the viewpoint of further improving the heat resistance of the thick film. The upper limit of the above elongation at break is not particularly limited, but for example, it is 200% or less, preferably 150% or less, and even more preferably 100% or less. Here, the resin film with a thickness of 30 μm is a resin film obtained by the following method. First, the photosensitive polyimide resin composition according to this embodiment is applied to a substrate such as a silicon wafer so that the film thickness after solvent removal is 30 μm. Next, the photosensitive polyimide resin composition formed on the substrate is pre-baked (dried) at 100°C for 5 minutes. Then, light from a high-pressure mercury lamp with wavelengths less than 365 nm cut off is applied at an integrated irradiation dose (calculated from the illuminance at 365 nm) of 250 mJ / cm². 2 More than 5,000mJ / cm 2 Exposure is performed by irradiating with the optimal exposure dose within the following range. After standing at room temperature for 15 minutes, the resin film is immersed in water to peel it off from the substrate, and then heat-treated under a nitrogen atmosphere at 200°C for 2 hours to obtain the desired result. In this embodiment, the optimal exposure dose is 250 mJ / cm². 2 More than 5,000mJ / cm 2 Within the following range, multiple different cumulative doses (250 mJ / cm²) 2 , 1,500 mJ / cm 2 2,000 mJ / cm² 2 4,000 mJ / cm² 2 , and 5,000 mJ / cm 2 The cumulative irradiation dose that provided the best balance of thick-film curability, thick-film flexibility, and thick-film heat resistance when exposed at the five points indicated above is the one shown. In this embodiment, "excellent thick-film curability" means that when the resin film thickness is, for example, 20 μm or more, a self-supporting film is obtained and the solubility in the developer (e.g., γ-butyrolactone) is low.

[0075] The glass transition temperature of the photosensitive polyimide resin composition according to this embodiment, when used as a resin film with a thickness of 30 μm, is preferably 180°C or higher, more preferably 190°C or higher, even more preferably 200°C or higher, even more preferably 210°C or higher, and even more preferably 230°C or higher, from the viewpoint of further improving the heat resistance of the thick film. The upper limit of the above glass transition temperature is not particularly limited, but for example, it is 300°C or lower, preferably 280°C or lower. The above glass transition temperature can be obtained by thermomechanical analysis (TMA). Here, the resin film with a thickness of 30 μm is a resin film obtained by the following method. First, the photosensitive polyimide resin composition according to this embodiment is applied to a substrate such as a silicon wafer so that the film thickness after solvent removal is 30 μm. Next, the photosensitive polyimide resin composition formed on the substrate is pre-baked (dried) at 100°C for 5 minutes. Then, light from a high-pressure mercury lamp with wavelengths less than 365 nm cut off is applied at an integrated irradiation dose (calculated from the illuminance at 365 nm) of 250 mJ / cm². 2 More than 5,000mJ / cm 2 Exposure is performed by irradiating with the optimal exposure dose within the following range. After standing at room temperature for 15 minutes, the resin film is immersed in water to peel it off from the substrate, and then heat-treated under a nitrogen atmosphere at 200°C for 2 hours to obtain the desired result. In this embodiment, the optimal exposure dose is 250 mJ / cm². 2 More than 5,000mJ / cm 2 Within the following range, multiple different cumulative doses (250 mJ / cm²) 2 , 1,500 mJ / cm 2 2,000 mJ / cm² 2 4,000 mJ / cm² 2 , and 5,000 mJ / cm 2 This cumulative irradiation dose showed the best balance of thick-film curability, thick-film flexibility, and thick-film heat resistance when exposed at the five points indicated above.

[0076] The photosensitive polyimide resin composition according to this embodiment is not particularly limited, but can be obtained, for example, by mixing a pre-closed ring polyimide resin (A) and a polyfunctional radical polymerizable compound (B) with at least one selected from the group consisting of a photopolymerization initiator, a solvent, an adhesion improver, a surface modifier, and a sensitizer, as needed.

[0077] 2. Resin film The photosensitive polyimide resin composition according to this embodiment can be used, for example, to form resin films such as resists used in the manufacture of electronic devices or permanent films (cured films) that constitute electronic devices. That is, the resin film according to this embodiment consists of the photosensitive polyimide resin composition or a cured product of the photosensitive polyimide resin composition. The resist described above is composed of a resin film obtained, for example, by applying the photosensitive polyimide resin composition according to this embodiment onto a substrate and removing the solvent as necessary. The above-mentioned permanent film is composed of a cured film obtained by exposing and developing the above-mentioned resin film, patterning it into a desired shape, and then curing it by heat treatment or the like. The permanent film can be suitably used as an insulating film, such as a surface protective film or an interlayer insulating film.

[0078] A surface protective film refers to an insulating film formed on the surface of an electronic component or electronic device, or on the surface of wiring on a wiring board, to protect the surface, and its type is not particularly limited. Examples of such surface protective films include a passivation film or buffer coat layer provided on a semiconductor element, or a cover coat provided on a flexible substrate.

[0079] An interlayer insulating film refers to an insulating film provided in a multilayer structure, and its type is not particularly limited. Examples of interlayer films include those used in semiconductor devices, such as interlayer insulating films that constitute the multilayer wiring structure of semiconductor devices, and build-up layers or core layers that constitute wiring substrates. Other examples of interlayer films include those used in display devices, such as planarization films that cover thin-film transistors in display devices, liquid crystal alignment films, protrusions provided on the color filter substrate of liquid crystal display devices, or partitions for forming the cathode of organic EL elements.

[0080] The method for applying the photosensitive polyimide resin composition according to this embodiment onto a substrate is not particularly limited and includes, for example, inkjet printing, spin coating, casting, microgravure, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, screen printing, flexographic printing, die coating, and the like.

[0081] When coating a substrate, it is preferable to adjust the solid content concentration of the photosensitive polyimide resin composition according to this embodiment to be in the range of 5% by mass or more and 50% by mass or less. As the solvent used during coating, a non-protic polar solvent is preferred from the viewpoint of solubility. Specifically, suitable examples include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N-benzyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-acetyl-ε-caprolactam, dimethylimidazolidinone, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, γ-butyrolactone, etc. These solvents may be used alone or in combination of two or more. To further improve coatability, solvents such as toluene, xylene, diethyl ketone, methoxybenzene, and cyclopentanone may be mixed in a range that does not adversely affect the solubility of the polymer.

[0082] Examples of the above-mentioned substrates include glass, silicon wafers, metal foil, and plastic film. Among these substrates, silicon wafers and copper foil are preferred.

[0083] Exposure of a film can be performed, for example, by irradiating a film made of a photosensitive polyimide resin composition formed on a substrate with light (usually ultraviolet light) through a photomask with a predetermined pattern. The exposed film has areas where light is blocked by the photomask and areas where light is irradiated, i.e., exposed areas and unexposed areas. In the exposed areas of the film, the polyimide resin in the photosensitive polyimide resin composition becomes crosslinked, forming a crosslinked polyimide film, which then forms a pattern in the subsequent development step. On the other hand, in the unexposed areas, the polyimide resin is not crosslinked, so it becomes an uncrosslinked polyimide film that is dissolved and removed by development.

[0084] After irradiation, the unexposed areas can be dissolved and removed with a developing solution to obtain the desired relief pattern. The UV irradiation dose is preferably 100 mJ / cm² as the cumulative irradiation dose. 2 More than 8,000mJ / cm 2 More preferably 200 mJ / cm² 2 More than 6,000mJ / cm 2 The following applies:

[0085] In the resin pattern forming method using the photosensitive polyimide resin composition according to this embodiment, it is preferable to use an organic solvent as the developer. The developer is not particularly limited as long as it can dissolve the photosensitive polyimide resin composition according to this embodiment. Specifically, suitable examples include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N-benzyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide, N-acetyl-ε-caprolactam, dimethylimidazolidinone, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and γ-butyrolactone. These developers may be used individually or in combination of two or more types.

[0086] Next, the relief pattern formed by development is washed with a rinsing solution to remove the developer. Suitable rinsing solutions include methanol, ethanol, isopropyl alcohol, and water, which have good miscibility with the developer. The relief pattern obtained by the above-described process can be heat-treated at a temperature selected from the range of 80°C to 250°C, the solvent can be dried, and a cured film (pattern) can be obtained by curing the photosensitive polyimide resin composition according to this embodiment. According to this embodiment, since a photosensitive polyimide resin composition with excellent developability, that is, in which the exposed areas are sufficiently cured and the unexposed areas are sufficiently removed, can be used, the resulting relief pattern can be obtained with high resolution.

[0087] The thickness of the resin film according to this embodiment is preferably 20 μm or more, more preferably 25 μm or more, even more preferably 30 μm or more, and preferably 85 μm or less, more preferably 60 μm or less. When the thickness is within the above range, it can be used as an excellent insulating film. As the thickness increases (i.e., as the amount of photosensitive polyimide resin composition applied to the substrate increases), problems often arise, particularly with the developer solubility of the polyimide resin. However, according to this embodiment, by using a pre-closed ring polyimide resin (A) having a specific structure and a specific end structure and having a specific molecular weight range, it is possible to achieve both excellent developer solubility and transparency even in such situations. Therefore, the resin film according to this embodiment can be suitably used, for example, in insulating film applications where high voltages are expected to be applied. The resin film obtained from the photosensitive polyimide resin composition according to this embodiment, which comprises a pre-closed ring polyimide resin (A) and a polyfunctional radical polymerizable compound (B), can effectively suppress the occurrence of cracks and other defects and exhibits excellent physical properties.

[0088] 3.Electronic equipment The electronic device according to this embodiment includes a resin film according to this embodiment. The electronic device according to this embodiment is not particularly limited as long as it comprises a resin film formed from the photosensitive polyimide resin composition according to this embodiment, but examples include a display device having the resin film according to this embodiment as a planarizing film or microlens; a semiconductor device having a multilayer wiring structure using the resin film according to this embodiment as an interlayer insulating film; a semiconductor device using the resin film according to this embodiment as a surface protective film for semiconductor elements or wiring substrates; and a semiconductor device using the resin film according to this embodiment as a build-up layer or core layer constituting a wiring substrate. Among these, a semiconductor device is preferred as the electronic device according to this embodiment. The electronic device according to this embodiment can be manufactured based on known information, except that it uses the resin film according to this embodiment. The electronic device according to this embodiment is equipped with a resin film that has an excellent balance between thick-film heat resistance and thick-film flexibility, making it less susceptible to dielectric breakdown and resulting in superior reliability. [Examples]

[0089] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited in any way by these examples.

[0090] <Rating> The evaluation methods used in this embodiment and comparative example are as follows.

[0091] (1) Weight average molecular weight (Mw) Mw was determined by GPC analysis. The equipment and analytical conditions used for the analysis are as follows. Equipment: Ecosec Elite HLC8420GPC (manufactured by Tosoh Corporation) Columns: TSKGelsuperAWM-H (Column size: 6.0mm x 15cm, Packed gel particle size: 9μm) x 2 (Manufactured by Tosoh Corporation) Eluent: Dimethylformamide with (20 mM lithium bromide and 100 mM phosphoric acid) Standard polystyrene: PStQuick Kit-H (manufactured by Tosoh Corporation) Flow rate: 0.6mL / min Column temperature: 40℃ Detector: RI (Refractive Index Detector)

[0092] (2) Patterning Photosensitive polyimide resin composition varnishes were prepared in the following examples and comparative examples. The varnishes obtained in each example and comparative example were applied to a silicon wafer using a spin coater to a film thickness of 30 μm after solvent removal, and then heated at 100°C for 5 minutes to remove the solvent. A predetermined amount of exposure was performed using a mask aligner, and the wafers were left to stand at room temperature for 15 minutes. Subsequently, γ-butyrolactone developer was sprayed for 30 seconds to remove unexposed areas, and the wafers were washed with methanol as a rinse solution. The solvent was then removed under air circulation.

[0093] The equipment and conditions used during exposure were as follows: Mask aligner: MA-10B (manufactured by Mikasa Corporation) Light source: High-pressure mercury lamp Illuminance: 12W / cm 2 (wavelength 365nm) Cumulative irradiation dose: 250~5,000 mJ / cm² 2 Developer: γ-butyrolactone Rinse solution: methanol Silicon wafer: 4-inch silicon wafer (manufactured by Advantech Co., Ltd.)

[0094] (3) Evaluation of thick film developability The patterns prepared in (2) above (a pattern with lines / spaces of 30 μm / 30 μm or a pattern with lines / spaces of 30 μm / 150 μm) were cut, and the cross-sections were observed using an SEM (TM3030plus (manufactured by Hitachi, Ltd.)) to check for the presence or absence of residue in the space areas (unexposed areas). A "○" was used if there was no residue in the space areas, and a "×" was used if there was residue in the space areas.

[0095] (4)Light transmittance The pre-closed ring polyimide resin (A) obtained in the synthesis example was dissolved in γ-butyrolactone to obtain a polyimide resin solution with a solid content of 3% by mass. Next, the light transmittance of this polyimide resin solution at a wavelength of 365 nm was measured using a spectrophotometer "product name: U3900H" manufactured by Hitachi, Ltd. and a cell with an optical path length of 10 mm.

[0096] (5) Elongation at break and glass transition temperature Photosensitive polyimide resin composition varnishes were prepared in the following examples and comparative examples. The varnishes obtained in each example and comparative example were applied to a silicon wafer using a spin coater to a film thickness of 30 μm after solvent removal, and then heated at 100°C for 5 minutes to remove the solvent. A predetermined amount of exposure was performed using a mask aligner, and the wafers were left to stand at room temperature for 15 minutes. Subsequently, the resin film was peeled off the silicon wafer by immersion in water and fired at 200°C for 2 hours under a nitrogen atmosphere. The elongation at break and glass transition temperature (Tg) of the obtained resin film were measured under the following conditions.

[0097] The equipment and measurement conditions used for measuring the elongation at break are as follows: Universal testing machine: Autograph AGS-X10kN (manufactured by Shimadzu Corporation) Tensile speed: 1 mm / min Specimen size: Dumbbell-shaped, size 6 (JIS K6251:2017), thickness 30 μm

[0098] The equipment and measurement conditions used for measuring the glass transition temperature are as follows: Tg was defined as the inflection point during the second heating step of the TMA measurement. Thermomechanical analyzer: TMASS6100 (manufactured by Hitachi High-Tech Science Co., Ltd.) Load: 100mN Temperature conditions: 30℃→220~300℃→30℃→300℃ Heating rate: 5-10°C / min

[0099] <Manufacturing of pre-closed ring polyimide resin (A)> Synthesis Example 1 In a 500 ml five-necked flask equipped with a nitrogen inlet tube, stirrer, thermometer, and condenser, 215.8492 g (0.642 mol) of 4,4'-oxybis[3-(trifluoromethyl)benzeneamine], 3.083 g (0.030 mol) of triethylamine, and 430.5 g of γ-butyrolactone (hereinafter, GBL) were added under nitrogen introduction, and the mixture was heated to 70°C while stirring. 136.6360 g (0.609 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride was added, and the mixture was reacted at 190°C for 5 hours. The mixture was diluted with 339.1 g of GBL to obtain 1069 g of polyimide varnish with a solid content of 30% by mass. GPC measurement revealed that the polystyrene-equivalent weight-average molecular weight of the obtained polyimide was 34,046. Next, 300.56 g of the obtained polyimide varnish and 7.7102 g of 2-isocyanatoethyl acrylate (Showa Denko K.K., Karenz AOI) were placed in a 500 mL four-necked flask equipped with a stirrer, thermometer, and condenser, and the mixture was reacted at 50°C for 5 hours. After that, the reaction solution was added dropwise to water to precipitate the polyimide, and the mixture was dried overnight at 70°C to obtain pre-closed ring polyimide resin (A1). The weight-average molecular weight of the obtained pre-closed ring polyimide resin (A1) was 34,664 on a polystyrene basis. Furthermore, the light transmittance of the obtained pre-closed ring polyimide resin (A1) at a wavelength of 365 nm was 92.0%.

[0100] <Examples and Comparative Examples> Example 1 8.1 g of the pre-closed ring polyimide resin (A1) obtained in Synthesis Example 1 was dissolved in 10.0 g of GBL. 4.065 g of ethoxylated polyglycerin acrylate (SA-TE60, manufactured by Sakamoto Pharmaceutical Co., Ltd.), 0.122 g of 1-hydroxycyclohexyl phenyl ketone (Omnirad 184, manufactured by BASF), 0.285 g of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819, manufactured by BASF), and 0.008 g of silicone-containing polymer (LE-304, silicone-based surface modifier, manufactured by Kyoeisha Chemical Co., Ltd.) were added and stirred until dissolved to obtain a photosensitive polyimide resin composition varnish. This photosensitive polyimide resin composition varnish was applied to a silicon wafer to a film thickness of 30 μm after drying and dried at 100°C for 5 minutes. Next, using a mask aligner (Mikasa Corporation, MA-10B) to filter out wavelengths below 365nm, the light from a high-pressure mercury lamp was used to accumulate an irradiation dose (calculated from the illuminance at 365nm) of 250 mJ / cm². 2 The film was exposed to light and allowed to stand for 15 minutes. The cured resin film was peeled off the silicon wafer, and the elongation at break and Tg were measured. When evaluating the thick-film developability, 0.004 g of KP-390 (manufactured by Shin-Etsu Chemical Co., Ltd., paint additive) was added to the above photosensitive polyimide resin composition varnish as an adhesion improver. The results are shown in Table 1.

[0101] Examples 2-7 and Comparative Examples 1-3 Except for changing the type of polyfunctional radical polymerizable compound to the compounds shown in Table 1 below, and further changing the cumulative irradiation dose to the values ​​shown in Table 1 below, a photosensitive resin composition was prepared in the same manner as in Example 1 above, and its properties were evaluated. The results are shown in Table 1. However, in the examples and comparative examples, the cumulative irradiation dose (exposure dose) was 250 mJ / cm². 2 More than 5,000mJ / cm 2 Within the following range, multiple different cumulative doses (250 mJ / cm²) 2 , 1,500 mJ / cm 2 2,000 mJ / cm² 2 4,000 mJ / cm² 2 , and 5,000 mJ / cm 2When exposed at the five points (listed above), the cumulative irradiation dose that provided the best balance of thick-film curability, thick-film flexibility, and thick-film heat resistance was adopted.

[0102] [Table 1]

[0103] As shown in Table 1, using the photosensitive polyimide resin composition of the example, a thick film with a thickness of 30 μm and high glass transition temperature and elongation at break was obtained. Furthermore, using the photosensitive polyimide resin composition of the example resulted in a pattern without residue in the void areas, and the photosensitive polyimide resin composition of the example exhibited excellent thick-film developability. In other words, the photosensitive polyimide resin composition of the example had an excellent balance of thick-film heat resistance, thick-film flexibility, and thick-film developability. On the other hand, the photosensitive polyimide resin compositions of Comparative Examples 1 to 3 had a low elongation at break when they were thick films with a thickness of 30 μm, and exhibited poor thick-film flexibility.

Claims

1. The present invention comprises a pre-closed ring polyimide resin (A) having the structure shown in formula (1) below, and a polyfunctional radical polymerizable compound (B) having a radical polymerizable functional group and an oxyalkylene group, The number of radical polymerizable functional groups in the polyfunctional radical polymerizable compound (B) is 3 or more and 100 or less. The total number of moles of oxyalkylene groups added to the polyfunctional radical polymerizable compound (B) is 5 or more and 100 or less. A photosensitive polyimide resin composition wherein the oxyalkylene group comprises at least one selected from an oxyethylene group and an oxypropylene group. 【Chemistry 1】 [In formula (1) above, R is a tetravalent group having 4 to 10 carbon atoms and having a cyclic structure, an acyclic structure, or a cyclic and an acyclic structure. A is a divalent group having 2 to 39 carbon atoms and having at least one group selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and an organosiloxane group. The main chain of A has -O- and -SO ２ -, -CO-, -CH ２ -, -C(CH ３ ) ２ -, -C ２ H ４ At least one group selected from the group consisting of O- and -S- may be present. n indicates the number of repeating units. The terminal of formula (1) is either the group shown in formula (2) or formula (3) below, or a hydrogen atom, and at least one of the terminals is the group shown in formula (2) or formula (3) below. 【Chemistry 2】 [In formulas (2) and (3) above, X and X ２ Each of these groups is independently a group having 2 to 15 carbon atoms and may have at least one group selected from the group consisting of ester bonds and double bonds. Y and Y 2 Each of these is independently either a hydrogen atom or a methyl group.

2. The photosensitive polyimide resin composition according to claim 1, wherein the weight-average molecular weight of the pre-closed ring polyimide resin (A) is 5,000 or more and 70,000 or less.

3. The photosensitive polyimide resin composition according to claim 1 or 2, wherein the content of the previously closed-ring polyimide resin (A) is 30% by mass or more when the total solid content of the photosensitive polyimide resin composition is 100% by mass.

4. The photosensitive polyimide resin composition according to any one of claims 1 to 3, wherein the content of the polyfunctional radical polymerizable compound (B) is 20 parts by mass or more and 100 parts by mass or less, when the amount of the pre-closed polyimide resin (A) contained in the photosensitive polyimide resin composition is 100 parts by mass.

5. The photosensitive polyimide resin composition according to any one of claims 1 to 4, wherein the radical polymerizable functional group comprises a (meth)acryloyl group.

6. The photosensitive polyimide resin composition according to any one of claims 1 to 5, wherein the number of radical polymerizable functional groups in the polyfunctional radical polymerizable compound (B) is six or more.

7. The photosensitive polyimide resin composition according to any one of claims 1 to 6, wherein the number average molecular weight of the polyfunctional radical polymerizable compound (B) is 500 or more and 10,000 or less.

8. The photosensitive polyimide resin composition is prebaked at 100 °C for 5 minutes, and then irradiated with light from a high-pressure mercury lamp that cuts wavelengths less than 365 nm within an optimal exposure amount in the range of ２ 5,000 mJ / cm ２ or less. After exposure, heat treatment is performed at 200 °C for 2 hours in a nitrogen atmosphere. The photosensitive polyimide resin composition according to any one of claims 1 to 7, wherein the elongation at break of the resin film having a film thickness of 30 μm is 8% or more.

9. The photosensitive polyimide resin composition was pre-baked at 100°C for 5 minutes, and then exposed to light from a high-pressure mercury lamp with wavelengths less than 365 nm filtered out at a rate of 250 mJ / cm². ２ 5,000mJ / cm or more ２ A photosensitive polyimide resin composition according to any one of claims 1 to 8, wherein the glass transition temperature of a resin film with a thickness of 30 μm obtained by irradiating with an optimal exposure dose within the following range and then heat-treating it under conditions of 200°C for 2 hours in a nitrogen atmosphere is 180°C or higher.

10. The photosensitive polyimide resin composition according to any one of claims 1 to 9, wherein the light transmittance at a wavelength of 365 nm is 80% or more when the previously closed-ring polyimide resin (A) is used as a 3% by mass solids solution.

11. The photosensitive polyimide resin composition according to any one of claims 1 to 10, wherein A in formula (1) contains an aromatic ring as an aromatic hydrocarbon group.

12. The photosensitive polyimide resin composition according to any one of claims 1 to 11, wherein A in formula (1) comprises at least one selected from the group consisting of the structures shown below. 【Transformation 3】 [In the formula, * indicates a bond.]

13. The photosensitive polyimide resin composition according to any one of claims 1 to 12, wherein the previously closed ring polyimide resin (A) contains at least one unit composed of 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, 4,4'-oxybis[3-(trifluoromethyl)benzeneamine], or 1,3-bis[2-(4-aminophenyl)-2-propyl]benzene.

14. A photosensitive polyimide resin composition according to any one of claims 1 to 13, further comprising at least one selected from the group consisting of a photopolymerization initiator, a solvent, an adhesion enhancer, a surface modifier, and a sensitizer.

15. A photosensitive polyimide resin composition according to any one of claims 1 to 14, for use in forming an insulating film.

16. A resin film comprising a photosensitive polyimide resin composition according to any one of claims 1 to 15 or a cured product of the photosensitive polyimide resin composition.

17. The resin film according to claim 16, wherein the film thickness is 20 μm or more.

18. An electronic device comprising the resin film described in Claim 17.

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