Modified polyimide resin, method for producing the same, and photosensitive polyimide cured film

Abstract

The application provides a modified polyimide resin and a preparation method and a photosensitive polyimide cured film thereof, wherein a polyimide intermediate 1 is obtained by reacting aromatic diamine monomers, a capping agent and aromatic dianhydride monomers, adding xylene and isoquinoline into the polyimide intermediate 1; and a modified polyimide resin is obtained by introducing a high-activity epoxy functional group into the polyimide intermediate 1. The application replaces the traditional propylene crosslinking with the crosslinking reaction of the epoxy group and the hydroxyl group by the method of chemical bonding, and the prepared modified polyimide resin has the low-temperature curing characteristics of the epoxy resin, and meanwhile retains the original high-temperature stability, mechanical properties and chemical resistance of the polyimide.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a modified polyimide resin, its preparation method, and a photosensitive polyimide cured film. Background Technology

[0002] Polyimide, due to its low dielectric constant, high thermal stability, and chemical resistance, is widely used in chip manufacturing and device packaging. Non-photosensitive polyimide requires the use of traditional photoresists to achieve patterning on the polyimide. However, the introduction of photoresists complicates the patterning process and increases the difficulty; photoresist stripping and subsequent etching processes can easily cause irreversible damage to the chip substrate. Against this backdrop, photosensitive polyimide, due to its inherent photosensitivity, allows for direct pattern transfer, greatly simplifying chip manufacturing processes and attracting widespread attention in chip manufacturing and packaging.

[0003] Traditional photosensitive polyimides are typically based on polyamic acid esters or polyamic acid salts. After film formation, they are converted into a polyimide structure through thermosetting, thus requiring high curing temperatures, generally above 300°C. However, in applications such as fan-out wafer-level packaging and fan-out planar packaging, excessively high temperatures can easily lead to wafer warping and solder joint cracking and detachment in molded circuits, directly affecting the stability and lifespan of components. Therefore, there is an urgent need to develop photosensitive polyimides that can be cured at around 200°C while retaining excellent substrate adhesion, thermal stability, mechanical properties, and dielectric properties—that is, low-temperature curable photosensitive polyimides.

[0004] Currently, there are four main approaches to achieving low-temperature curing of photosensitive polyimides. First, by modifying the molecular structure of polyamic acid and introducing specific functional groups into its side chains, the imidization temperature can be lowered. For example, CN115343914B and CN117866000B modify polyamic acid molecules by introducing fluoroalkane side chains and nitrogen heterocyclic structures, respectively, to achieve low-temperature curing and low-dielectric photosensitive polyimide materials. However, the introduction of fluoroalkane side chains generally leads to excessively high raw material costs, and the mechanical properties after film formation are relatively poor; the nitrogen heterocyclic diamine structure increases the processing steps and imposes specific restrictions on the monomer structure, limiting its widespread application. CN116909100B uses a diamine containing a azole multi-arm structure as a monomer, achieving low-temperature curing while enhancing the adhesion of the photosensitive polyimide to the copper substrate, but its glass transition temperature is low and its thermal stability is relatively poor. Second, polyamic acid salts are used as precursors. For example, CN114957662B first synthesizes polyamic acid salts, then adds a low-temperature curing accelerator to the system. The salts are relatively easy to decompose, thus achieving imidization at around 250℃, thereby realizing the low-temperature curing of photosensitive polyimide. However, compared to polyamic acid salts, the salts have poorer stability, limiting their large-scale use. Third, using polyisoimide as a precursor, it transforms into polyimide upon heating without the release of small molecules. However, isoimide is unstable and requires specific monomers; otherwise, the adhesive is prone to gelation. Fourth, pre-imidizing polyamic acid as a precursor eliminates the need for further imidization during subsequent curing; only organic solvents and low-boiling-point small molecules need to be removed, resulting in a lower curing temperature. Patents JP5585022B2 and JP2003330190A first synthesize soluble polyimide with hydroxyl groups and add epoxidants such as glycidyl methacrylate, achieving photocrosslinking of the polyimide under the action of a photoinitiator. However, problems such as additive escaping from the system during curing leading to film thickness shrinkage and poor chemical resistance after film formation exist. Therefore, simultaneously achieving low-temperature curing, superior thermal stability, and chemical resistance of photosensitive polyimides is a pressing issue that needs to be addressed. Summary of the Invention

[0005] The purpose of this application is to provide a modified polyimide resin and its preparation method, which reduces the curing temperature of the photosensitive polyimide resin composition while retaining excellent thermal stability, mechanical properties, and chemical resistance. The specific technical solution is as follows:

[0006] The first aspect of this application provides a modified polyimide resin, the structure of which is shown in Formula 1.

[0007]

[0008] Ar1 is selected from Ar2 is selected from Ar3 is selected from The hydroxyl groups in the modified polyimide resin are replaced by epoxy-containing groups, with a substitution ratio of 40% to 80%; the epoxy-containing groups are selected from...

[0009] The degree of polymerization n of the modified polyimide resin satisfies: 10 ≤ n ≤ 100. This application introduces highly reactive epoxy functional groups into the polyimide resin, giving it the characteristics of low-temperature curing of epoxy resin, while retaining the original high-temperature stability, mechanical properties, and chemical resistance of polyimide.

[0010] In one embodiment of this application, the substitution ratio is preferably 60% to 80%.

[0011] A second aspect of this application provides a photosensitive polyimide resin composition comprising a modified polyimide resin, an organic solvent, and additives; wherein the organic solvent is selected from at least one of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, γ-butyrolactone, γ-valerolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, ethyl lactate, and dimethylimidazolinone; the additives include a photo-induced alkalizing agent and a stabilizer, and the solid content of the photosensitive polyimide composition is 20% to 40%.

[0012] In one embodiment of this application, the photo-induced alkali-generating agent is selected from at least one of 9-anthramethylpiperidin-1-carboxylate, 9-anthramethyl N,N-diethylcarbamate, 1-(anthraquinone-2-yl)ethylimidazolium-1-carboxylic acid, cyclohexyl-2-(3-benzoylphenyl)propionic acid, and guanidino-2-(3-benzoylphenyl)propionic acid; the stabilizer is selected from at least one of resorcinol diglycidyl ether, p-methoxyphenol, p-dinitrobenzene, 2,5-methylbenzoquinone, and p-benzylaminophenol; based on the total mass of the photosensitive polyimide composition, the mass percentage of the modified polyimide resin is 15% to 40%, the mass percentage of the photo-induced alkali-generating agent is 0.5% to 4%, and the mass percentage of the stabilizer is 0.1% to 0.5%.

[0013] A third aspect of this application provides a photosensitive polyimide cured film, which is cured from the photosensitive polyimide resin composition described in the second aspect of this application.

[0014] In one embodiment of this application, the curing temperature of the photosensitive polyimide curing film is ≤200℃.

[0015] A fourth aspect of this application provides a method for preparing a modified polyimide resin, wherein the preparation method includes the following steps:

[0016] (1) Dissolve the aromatic diamine monomer in a high-boiling-point polar organic solvent, and add the capping agent and aromatic dianhydride monomer in sequence to react and obtain a capped polyamic acid solution; the boiling point of the high-boiling-point polar organic solvent is 150℃~250℃;

[0017] (2) Add xylene and isoquinoline to the polyamic acid solution, heat under reflux to obtain polyimide intermediate 1 solution;

[0018] (3) Add the polyimide intermediate 1 solution to deionized water, stir, filter and dry to obtain polyimide intermediate 1;

[0019] (4) The polyimide intermediate 1 is dissolved in a high-boiling-point polar organic solvent, an epoxy modifier and an alkaline catalyst are added, and the modified intermediate 2 solution is obtained after the reaction; the boiling point of the high-boiling-point polar organic solvent is 150℃~250℃.

[0020] (5) Add a hydroxyl protecting agent to the modified intermediate 2 solution and react to obtain the modified intermediate 3 solution;

[0021] (6) Cool the modified intermediate 3 solution to 0-20°C and add peroxy acid to it to obtain a modified intermediate 4 solution with epoxy group end group;

[0022] (7) Add a hydroxyl deprotecting agent dropwise to the solution of the modified intermediate 4, the reaction temperature is 20-50℃, the reaction time is 2-6 hours, and a polyimide solution with epoxy groups is obtained;

[0023] (8) The polyimide solution with epoxy groups is added to deionized water, stirred, and flocculent precipitate is formed. The precipitate is filtered and dried to obtain modified polyimide resin.

[0024] In one embodiment of this application, the high-boiling-point polar organic solvent is selected from at least one of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, γ-butyrolactone, γ-valerolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, ethyl lactate, and dimethylimidazolinone; the aromatic dianhydride monomer is selected from at least one of biphenyl ether dianhydride, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, 4,4'-terephthalodioxydiphthalic anhydride, and benzophenone tetracarboxylic dianhydride; the aromatic diamine monomer is selected from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 3,3'-dihydroxybiphenyldiamine, 4,4'-diphenyl ether dianhydride, and diphenyl ether dianhydride. - At least one of methylene bis(2-aminophenol), 2,2-bis(3-amino-4-hydroxyphenyl)propane, and bis(3-amino-4-hydroxyphenyl) sulfone; the molar ratio of the aromatic dianhydride monomer to the aromatic diamine monomer is 1.01 to 1.15:1, preferably 1.01 to 1.05:1; the end-capping agent is selected from at least one of p-aminophenol, 4-[2-(4-aminophenyl)diazepine]phenol, o-amino-p-cresol, 3-amino-4-hydroxybiphenyl, 2-amino-4,5-dimethylphenol, and o-amino-p-tert-butylphenol, and the molar ratio of the end-capping agent to the aromatic diamine monomer is 0.01 to 0.1:1.

[0025] In one embodiment of this application, the epoxy modifier in step (4) is selected from at least one of glycidyl methacrylate, allyl glycidyl ether, 2-[[4-(2-propen-1-oxy)phenoxy]methyl]-ethylene oxide and 4-vinylbenzyl glycidyl ether; the alkaline catalyst is selected from at least one of triethylamine, butylamine, isopropylamine, sodium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene and pyridine; the molar ratio of the epoxy modifier to the aromatic dianhydride monomer is 0.5 to 3:1, and the molar ratio of the alkaline catalyst to the aromatic dianhydride monomer is 0.03 to 0.3:1.

[0026] In one embodiment of this application, the hydroxyl protectant in step (5) is selected from at least one of tert-butyldimethylchlorosilane, benzyl isopropenyl ether and triphenylchloromethane, and the molar ratio of the hydroxyl protectant to the aromatic dianhydride monomer is 0.5 to 3:1.

[0027] In one embodiment of this application, the peroxy acid in step (6) is selected from at least one of peroxyformic acid, peracetic acid, perbenzoic acid, m-chloroperoxybenzoic acid and peroxytrifluoroacetic acid, and the molar ratio of the peroxy acid to the aromatic dianhydride monomer is 1.5 to 3:1.

[0028] In one embodiment of this application, the hydroxyl deprotecting agent in step (7) is selected from at least one of acetic acid, potassium carbonate, tetra(trifluoromethanesulfonic acid) hafnium, lithium acetate, 1,8-diazabicyclo(5,4,0)-7-undecene and tetrabutylammonium fluoride, and the molar ratio of the hydroxyl deprotecting agent to the aromatic dianhydride monomer is 1.5 to 3.5:1.

[0029] The beneficial effects of this application are:

[0030] This application provides a modified polyimide resin, a photosensitive polyimide resin composition, and a photosensitive polyimide cured film. The structure of the modified polyimide resin is shown in Formula 1. This application introduces highly reactive epoxy functional groups into the polyimide resin, enabling it to possess the low-temperature curing characteristics of epoxy resins while retaining the original high-temperature stability, mechanical properties, and chemical resistance of polyimide. This also lowers the curing temperature of the photosensitive polyimide resin composition, achieving a photosensitive polyimide cured film that can be cured at low temperatures and exhibits superior thermal stability and chemical resistance.

[0031] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0033] Figure 1 This is an optical microscope image of the photosensitive polyimide cured film after exposure and development in Example 5;

[0034] Figure 2 The pattern after exposure and development of the photosensitive polyimide cured film in Example 5;

[0035] Figure 3 The 1H NMR spectrum of the modified polyimide resin in Example 5;

[0036] Figure 4 The infrared spectrum of the modified polyimide resin in Example 5;

[0037] Figure 5 The infrared spectrum of the photosensitive polyimide cured film in Example 5 is shown. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0039] The first aspect of this application provides a modified polyimide resin, the structure of which is shown in Formula 1.

[0040]

[0041] Ar1 is selected from Ar2 is selected from Ar3 is selected from The hydroxyl groups in the modified polyimide resin are replaced by epoxy-containing groups, with a substitution ratio of 40% to 80%; the epoxy-containing groups are selected from...

[0042] The degree of polymerization n of the modified polyimide resin satisfies: 10 ≤ n ≤ 100. This application introduces highly reactive epoxy functional groups into the polyimide resin, giving it the characteristics of low-temperature curing of epoxy resin, while retaining the original high-temperature stability, mechanical properties, and chemical resistance of polyimide.

[0043] In one embodiment of this application, the hydroxyl groups in the modified polyimide resin are replaced by epoxy-containing groups, wherein the substitution ratio is 40% to 80%, preferably 60% to 80%, for example, it can be 40%, 43%, 45%, 48%, 50%, 53%, 55%, 58%, 60%, 63%, 65%, 68%, 70%, 73%, 75%, 78%, 80%, or any range of two such values. In one embodiment of this application, n can be 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or any range of two such values.

[0044] This application does not impose any particular restrictions on the position of the hydroxyl group replaced by an epoxy group, as long as the purpose of this application can be achieved.

[0045] A second aspect of this application provides a photosensitive polyimide resin composition comprising a modified polyimide resin, an organic solvent, and additives; wherein the organic solvent is selected from at least one of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, γ-butyrolactone, γ-valerolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, ethyl lactate, and dimethylimidazolinone; the additives include a photo-induced alkalizing agent and a stabilizer, and the solid content of the photosensitive polyimide composition is 20% to 40%.

[0046] In one embodiment of this application, the solid content of the photosensitive polyimide resin composition can be a range consisting of any two values, such as 20%, 22%, 25%, 30%, 35%, 37%, and 40%.

[0047] In one embodiment of this application, the modified polyimide resin has a mass percentage content of 15% to 40% based on the total mass of the photosensitive polyimide composition; for example, the modified polyimide resin may have a mass percentage content of 15%, 20%, 25%, 30%, 35%, 40%, or any combination of two of these values ​​based on the total mass of the photosensitive polyimide composition.

[0048] In one embodiment of this application, the photo-induced alkali-producing agent is selected from at least one of 9-anthramethylpiperidine-1-carboxylate tert-butyl ester, 9-anthramethyl N,N-diethylcarbamate, 1-(anthraquinone-2-yl)ethylimidazolium-1-carboxylic acid, cyclohexyl-2-(3-benzoylphenyl)propionic acid, and guanidino-2-(3-benzoylphenyl)propionic acid; the mass percentage of the photo-induced alkali-producing agent is 0.5% to 4% based on the total mass of the photosensitive polyimide composition; for example, the mass percentage of the photo-induced alkali-producing agent can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or a range of any two of these values ​​based on the total mass of the photosensitive polyimide composition.

[0049] In one embodiment of this application, the stabilizer is selected from at least one of resorcinol diglycidyl ether, p-methoxyphenol, p-dinitrobenzene, 2,5-methylbenzoquinone, and p-benzylaminophenol; the mass percentage of the stabilizer is 0.1% to 0.5% based on the total mass of the photosensitive polyimide composition; for example, the mass percentage of the stabilizer may be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, or a range of any two of these values ​​based on the total mass of the photosensitive polyimide composition.

[0050] In one embodiment of this application, the additive may further include leveling agents, curing accelerators, toughening agents, and plasticizers. This application does not impose any particular limitation on the types of leveling agents, curing accelerators, toughening agents, and plasticizers, as long as they achieve the purpose of this application.

[0051] In this application, the photosensitive polyimide resin composition, apart from the modified polyimide resin and additives, consists of organic solvents in the remainder.

[0052] The third aspect of this application provides a photosensitive polyimide cured film, which is cured from the photosensitive polyimide resin composition described in the second aspect of this application.

[0053] In one embodiment of this application, the curing temperature of the photosensitive polyimide curing film is ≤200℃.

[0054] A fourth aspect of this application provides a method for preparing a modified polyimide resin, wherein the preparation method includes the following steps:

[0055] (1) Dissolve the aromatic diamine monomer in a high-boiling-point polar organic solvent, and add the capping agent and aromatic dianhydride monomer in sequence to react and obtain a capped polyamic acid solution; the boiling point of the high-boiling-point polar organic solvent is 150℃~250℃;

[0056] (2) Add xylene and isoquinoline to the polyamic acid solution, heat under reflux to obtain polyimide intermediate 1 solution;

[0057] (3) Add the polyimide intermediate 1 solution to deionized water, stir, filter and dry to obtain polyimide intermediate 1;

[0058] (4) The polyimide intermediate 1 is dissolved in a high-boiling-point polar organic solvent, an epoxy modifier and an alkaline catalyst are added, and the modified intermediate 2 solution is obtained after the reaction; the boiling point of the high-boiling-point polar organic solvent is 150℃~250℃.

[0059] (5) Add a hydroxyl protecting agent to the modified intermediate 2 solution and react to obtain the modified intermediate 3 solution;

[0060] (6) Cool the modified intermediate 3 solution to 0-20°C and add peroxy acid to it to obtain a modified intermediate 4 solution with epoxy group end group;

[0061] (7) Add a hydroxyl deprotecting agent dropwise to the solution of the modified intermediate 4, the reaction temperature is 20-50℃, the reaction time is 2-6 hours, and a polyimide solution with epoxy groups is obtained;

[0062] (8) The polyimide solution with epoxy groups is added to deionized water, stirred, and flocculent precipitate is formed. The precipitate is filtered and dried to obtain modified polyimide resin.

[0063] In one embodiment of this application, the high-boiling-point polar organic solvent is selected from at least one of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, γ-butyrolactone, γ-valerolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, ethyl lactate, and dimethylimidazolinone; the aromatic dianhydride monomer is selected from biphenyl ether dianhydride, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, 4,4'-terephthalodioxydiphthalic anhydride, and benzophenone tetracarboxylic acid. The aromatic diamine monomer is selected from at least one of the following: 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 3,3'-dihydroxybenzyldiamine, 4,4-methylenebis(2-aminophenol), 2,2-bis(3-amino-4-hydroxyphenyl)propane, and bis(3-amino-4-hydroxyphenyl)sulfone; the molar ratio of the aromatic dianhydride monomer to the aromatic diamine monomer is 1.01 to 1.15:1, preferably 1.01 to 1.05:1.

[0064] In one embodiment of this application, the molar ratio of the aromatic dianhydride monomer to the aromatic diamine monomer can be 1.01:1, 1.02:1, 1.03:1, 1.04:1, 1.05:1, 1.08:1, 1.12:1, 1.15:1, or a range of any two of these values.

[0065] In one embodiment of this application, the capping agent is selected from at least one of p-aminophenol, 4-[2-(4-aminophenyl)diazepine]phenol, o-amino-p-cresol, 3-amino-4-hydroxybiphenyl, 2-amino-4,5-dimethylphenol, and o-amino-p-tert-butylphenol, and the molar ratio of the capping agent to the aromatic diamine monomer is 0.01 to 0.1:1.

[0066] In one embodiment of this application, the molar ratio of the capping agent to the aromatic diamine monomer can be 0.01:1, 0.02:1, 0.03:1, 0.05:1, 0.06:1, 0.08:1, 0.09:1, 0.1:1, or a range of any two of these values.

[0067] In one embodiment of this application, the reaction atmosphere in step (1) is an inert gas atmosphere, for example, an inert gas can be introduced into the reaction vessel. In this application, there is no particular limitation on the type of inert gas; any inert gas known to those skilled in the art can be used, such as at least one of argon or nitrogen. This application does not particularly limit the reaction vessel, as long as it can achieve the purpose of this application.

[0068] In one embodiment of this application, the reaction temperature of step (1) is 5 to 20°C. For example, the reaction temperature of step (1) can be 5°C, 8°C, 10°C, 12°C, 14°C, 16°C, 18°C, 20°C or a range of any two of these values.

[0069] In one embodiment of this application, the reaction time of step (1) is 10 to 20 hours. For example, the reaction time of step (1) can be 10 hours, 12 hours, 14 hours, 15 hours, 16 hours, 18 hours, 20 hours, or a range of any two of these values.

[0070] This application does not impose any particular restrictions on the method of adding the capping agent and aromatic dianhydride monomer in step (1), as long as the purpose of this application can be achieved. For example, the aromatic dianhydride monomer can be slowly added dropwise in 1 to 8 portions to a high-boiling-point polar organic solvent containing the aromatic diamine monomer.

[0071] In one embodiment of this application, the mass ratio of xylene to the aromatic diamine monomer is 1.2 to 1.6:1. For example, the mass ratio of xylene to the aromatic diamine monomer can be 1.2:1, 1.25:1, 1.3:1, 1.35:1, 1.4:1, 1.45:1, 1.5:1, 1.55:1, 1.6:1, or a range consisting of any two of these values.

[0072] In one embodiment of this application, the mass ratio of isoquinoline to the aromatic diamine monomer is 0.05 to 0.1:1. For example, the mass ratio of isoquinoline to the aromatic diamine monomer can be 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, or a range consisting of any two of these values.

[0073] In one embodiment of this application, in step (2), a water separator and a condenser can be connected to the upper end of the reaction vessel, and the reflux time is 2 to 8 hours.

[0074] In one embodiment of this application, the epoxy modifier in step (4) is selected from at least one of glycidyl methacrylate, allyl glycidyl ether, 2-[[4-(2-propen-1-oxy)phenoxy]methyl]-ethylene oxide and 4-vinylbenzyl glycidyl ether; the alkaline catalyst is selected from at least one of triethylamine, butylamine, isopropylamine, sodium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene and pyridine; the molar ratio of the epoxy modifier to the aromatic dianhydride monomer is 0.5 to 3:1, and the molar ratio of the alkaline catalyst to the aromatic dianhydride monomer is 0.03 to 0.3:1.

[0075] In one embodiment of this application, the molar ratio of the epoxy modifier to the aromatic dianhydride monomer can be 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, or a range consisting of any two of these values.

[0076] In one embodiment of this application, the molar ratio of the alkaline catalyst to the aromatic dianhydride monomer can be 0.03:1, 0.06:1, 0.1:1, 0.2:1, 0.25:1, 0.3:1, or a range of any two of these values.

[0077] In one embodiment of this application, the reaction temperature of step (4) is 50-150°C and the reaction time is 6-18 hours.

[0078] In one embodiment of this application, the hydroxyl protectant in step (5) is selected from at least one of tert-butyldimethylchlorosilane, benzyl isopropenyl ether, and triphenylchloromethane. The molar ratio of the hydroxyl protectant to the aromatic dianhydride monomer is 0.5 to 3:1. For example, the molar ratio of the hydroxyl protectant to the aromatic dianhydride monomer can be 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, or a range consisting of any two of these values.

[0079] In one embodiment of this application, the reaction temperature in step (5) is 10-30°C and the reaction time is 0.5-2 hours.

[0080] In one embodiment of this application, the peroxy acid in step (6) is selected from at least one of peroxyformic acid, peracetic acid, perbenzoic acid, m-chloroperoxybenzoic acid, and peroxytrifluoroacetic acid. The molar ratio of the peroxy acid to the aromatic dianhydride monomer is 1.5 to 3:1. For example, the molar ratio of the peroxy acid to the aromatic dianhydride monomer can be 1.5:1, 1.8:1, 2:1, 2.3:1, 2.5:1, 2.8:1, 3:1, or a range of any two of these values.

[0081] In one embodiment of this application, the reaction temperature of step (6) is 0 to 20°C and the reaction time is 3 to 8 hours.

[0082] In one embodiment of this application, the hydroxyl deprotecting agent in step (7) is selected from at least one of acetic acid, potassium carbonate, tetra(trifluoromethanesulfonic acid) hafnium, lithium acetate, 1,8-diazabicyclo(5,4,0)-7-undecene, and tetrabutylammonium fluoride. The molar ratio of the hydroxyl deprotecting agent to the aromatic dianhydride monomer is 1.5 to 3.5:1. For example, the molar ratio of the hydroxyl deprotecting agent to the aromatic dianhydride can be 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, or a range consisting of any two of these values.

[0083] In one embodiment of this application, the aromatic diamine monomer is 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, the aromatic dianhydride monomer is biphenyl ether dianhydride, the end-capping agent is p-aminophenol, the epoxy modifier is glycidyl methacrylate, and the preparation process of the modified polyimide resin can be represented as follows:

[0084]

[0085] The positions of the epoxy groups in the preparation of the modified polyimide resin are merely illustrative examples to illustrate the specific steps of replacing hydroxyl groups with epoxy groups. In actual synthesis, epoxy groups randomly replace the hydroxyl groups in formula M, with a substitution ratio of 40% to 80%, preferably 60% to 80%.

[0086] In one embodiment of this application, a photosensitive polyimide resin composition is obtained by uniformly mixing the modified polyimide resin, organic solvent, and stabilizer. The additives include a photo-induced alkali-generating agent and a stabilizer. The photosensitive polyimide composition can be cured by heating it to a certain temperature, for example, 200°C. The curing process of the photosensitive polyimide composition can be represented as follows:

[0087]

[0088] The positions of the epoxy groups in the photosensitive polyimide composition during curing are merely illustrative examples to illustrate the low-temperature curing process of epoxy groups. The curing process of the photosensitive polyimide composition is also illustrative to illustrate the changes in the groups before and after the epoxy and hydroxyl groups react to cure. In actual synthesis, epoxy groups can react randomly with hydroxyl groups, ultimately causing the photosensitive polyimide composition to polymerize into macromolecular chains and thus cure. After curing, the photosensitive polyimide composition yields a photosensitive polyimide cured film. The curing temperature of the photosensitive polyimide cured film is ≤200℃, and it exhibits superior thermal stability, mechanical properties, and chemical resistance.

[0089] Example

[0090] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0091] Test methods and equipment:

[0092] Substitution ratio test of epoxy groups

[0093] Weigh 10 mg of the sample to be tested (modified polyimide resin powder), dissolve it in 1 mL of dimethyl sulfoxide-d6 (DMSO-d6, Sigma-Aldrich), and perform 1H NMR spectroscopy on it using a Bruker AVANCE III 400 MHz (Bruker Optik GmbH, Germany) NMR spectrometer. The integrated area of ​​the characteristic peak of the epoxy hydrogen is denoted as A1; the integrated area of ​​the characteristic peak of the benzene ring hydrogen is denoted as A2, using it as a standard.

[0094] Based on the type and molar amount of aromatic dianhydride monomers and aromatic diamine monomers added in the reaction, the molecular structure of the modified polyimide resin when the hydroxyl groups in the modified polyimide resin are replaced by epoxy groups with a substitution ratio of 100% can be obtained. The smallest repeating structure in the molecular structure is regarded as a repeating unit. The number of epoxy group hydrogens in the repeating unit is denoted as B1, and the number of benzene ring hydrogens is denoted as B2. The substitution ratio of epoxy group is (A1 / A2) / (B1 / B2)×100%.

[0095] Aggregation test

[0096] Weigh 10 mg of the sample to be tested (modified polyimide resin powder), dissolve it in 1 mL of dimethylformamide (DMF, Sigma-Aldrich), and determine its relative molecular weight and molecular weight distribution using a Thermo Fisher 2695 gel permeation chromatography system (Thermo Fisher Scientific Inc., USA). Based on the types of aromatic diamine monomers and aromatic dianhydride monomers, the structure of the repeating unit in the modified polyimide resin can be determined, and the molecular weight of the repeating unit can be calculated.

[0097] The degree of polymerization n of modified polyimide resin = relative molecular mass / molecular mass of repeating unit.

[0098] Photosensitive test

[0099] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine (MIDAS, model MDA400M). 2Exposure was performed using masks of different sizes to control the light source. Subsequently, a 2.38 wt% tetramethylammonium hydroxide aqueous solution was used as the developer, and deionized water was used as the cleaning solution to obtain the photolithographic pattern. The dried silicon wafer with the photolithographic pattern was placed in a nitrogen atmosphere at 200°C for 1 hour for curing, resulting in a photosensitive polyimide cured film with the photolithographic pattern formed by curing the photosensitive polyimide resin composition. The pattern on the photosensitive polyimide cured film was analyzed using optical microscopy and scanning electron microscopy, and the minimum size that maintains the complete pattern was defined as the resolution of the photosensitive polyimide cured film.

[0100] Thermal expansion coefficient test

[0101] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and spin-coated at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. Subsequently, the photosensitive polyimide resin composition was cured at 200°C for 1 hour and cooled to room temperature to obtain a photosensitive polyimide cured film. The silicon wafer coated with the photosensitive polyimide cured film was immersed in a 1% hydrofluoric acid solution to detach the photosensitive polyimide cured film from the silicon wafer. The acid solution on the surface of the photosensitive polyimide cured film was washed off with deionized water, and then cut into strips of 20 × 5 mm. The thickness of the photosensitive polyimide cured film was measured using an optical film thickness gauge (SR-C, Wuhan Yiguang Technology), denoted as n. The strip-shaped photosensitive polyimide cured film was tested using a thermomechanical analyzer (TMA instrument) (Mettler TMA / SDTA2+, Mettler Toledo), with data collected at a rate of 5℃ / min between 50℃ and 300℃ to obtain the coefficient of thermal expansion.

[0102] Curing rate test

[0103] The modified polyimide resin and the photosensitive polyimide cured film were characterized using an infrared spectroscopy system (Thermo, Nicolet IS50). The out-of-plane vibrational peak of the carbon-based resin was taken as the reference peak, with an elution position of 1720 cm⁻¹. -1 Nearby, the modified polyimide resin and the photosensitive polyimide cured film were at 1720 cm⁻¹. -1 The integral areas near the epoxy groups are denoted as R and R', respectively. The epoxy groups are located at 915 cm⁻¹. -1 Characteristic peaks appear nearby, with the modified polyimide resin and photosensitive polyimide cured film showing a peak at 915 cm⁻¹. -1 The integral areas near the solidified surface are denoted as M and M', respectively. The curing rate is calculated using the following formula:

[0104] Curing rate = (1 - (M' / R') / (M / R)) × 100%.

[0105] Mechanical performance testing

[0106] The photosensitive polyimide cured film was cut into dumbbell strips with a width of 10 mm, an effective test length of 50 mm, and a total length of 80 mm. The tensile strength, Young's modulus, elongation at break, and other mechanical properties of the photosensitive polyimide cured film were characterized using a tensile testing machine (E44.304-B, Meters Industrial System) (refer to national standard GB / T 1040.2-2006 Determination of Tensile Properties of Plastics).

[0107] Chemical resistance test

[0108] Take a photosensitive polyimide cured film, measure its film thickness and record it as n1. Immerse the photosensitive polyimide cured film in N-methylpyrrolidone, dimethylacetamide, and 1,4-butyrolactone respectively. After immersion for 1 hour, take it out and measure its film thickness, record it as n2. The film removal rate after immersion is Q = (n1-n2) / n1×100%.

[0109] Taking the sample of Example 5 as an example, the calculation method for the substitution ratio of epoxy groups and the curing rate is as follows:

[0110] Figure 1 This is an optical microscope image of the photosensitive polyimide cured film after exposure and development in Example 5. The curing temperature is 200℃. The side length of the white rectangle corresponding to the arrow is 18.428μm, which corresponds to a mask size of 20μm, i.e., a resolution of 20μm. Figure 2 The pattern is the one formed by curing the photosensitive polyimide resin composition at 200°C after exposure and development in Example 5; wherein, Figure 2 The structure of the dumbbell-shaped photosensitive polyimide cured film can be seen in the image. Figure 2 The light-colored rectangle in the middle is a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0111] Figure 3 The 1H NMR spectrum of the modified polyimide resin in Example 5 is shown below. The peaks at δ = 1.91 and δ = 2.17 are characteristic peaks of epoxy hydrogen, and their integrated area is denoted as A1. The peaks between δ = 6.5 and δ = 8.5 represent the signal of benzene ring hydrogen, and are used as the standard; their integrated area is denoted as A2. Processing the 1H NMR spectrum using MestReNova software yields an integrated area of ​​A1 = 0.146 for the epoxy group peak and A2 = 1 for the benzene ring hydrogen peak. When 100% substitution is achieved, the number of epoxy group hydrogens in the repeating unit of the modified polyimide resin is denoted as B1 = 4, and the number of benzene ring hydrogens is denoted as B2 = 12. The substitution ratio of the epoxy group is calculated as (A1 / A2) / (B1 / B2) × 100% = (0.146 / 1) / (4 / 12) × 100% = 44%.

[0112] Figure 4The image shows the infrared spectrum of the modified polyimide resin in Example 5. Figure 5 The infrared spectrum of the photosensitive polyimide resin composition in Example 5 after curing at 200°C for 1 hour is shown. Figure 4 The characteristic peak of the epoxide group corresponds to 917 cm⁻¹. -1 Near the same location, the corresponding integral area is M = 1.39; the position of the baseline carbon-based peak is 1724 cm⁻¹. -1 Near the same point, the corresponding integral area is R = 25.69; Figure 5 The characteristic peak of the epoxy group after intermediate curing corresponds to 917 cm⁻¹. -1 Near the same point, the corresponding integral area is M' = 0.02, and the position of the baseline carbon-based peak is 1724 cm⁻¹. -1 Nearby, the corresponding integral area R' = 5.27.

[0113] The curing rate of the photosensitive polyimide resin composition can be calculated as follows: Ct=(1-(M' / R') / (M / R))×100%=(1-(0.02 / 5.27) / (1.39 / 25.69))=93%.

[0114] Example 1

[0115] <Synthetic Intermediate 1 for Polyimide>

[0116] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0117] <Preparation of modified polyimide resin>

[0118] The above-mentioned polyimide intermediate 1 was dissolved in 40 mL of dry N-methylpyrrolidone. 2.84 g of glycidyl methacrylate was added as an epoxy modifier, and 0.1 g of triethylamine was slowly added as a basic catalyst. The solution was heated to 70 °C and the reaction was continued for 12 h. After the reaction was completed, the solution was cooled to room temperature. 9 g of tert-butyldimethylchlorosilane was added dropwise as a hydroxyl protecting agent to the cooled solution, and the mixture was stirred for 30 min. The mixture was cooled to 5 °C, and 6.88 g of m-chloroperoxybenzoic acid was slowly added dropwise, and the mixture was stirred for 4 h. After the reaction was completed, 10.4 g of tetrabutylammonium fluoride was added to the mixture as a hydroxyl deprotecting agent, and the mixture was reacted at 25 °C for 2 h. The mixture was then slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a pale yellow flaky precipitate. The pale yellow flaky precipitate was filtered and dried to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.31 (s, methyl hydrogen), 1.91–2.18 (m, epoxy hydrogen), 2.52 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.30 (m, alcohol hydroxyl hydrogen), 6.98–8.02 (m, aromatic ring hydrogen), 10.51 (s, phenolic hydroxyl hydrogen).

[0119] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=45.

[0120] <Preparation of Photosensitive Polyimide Resin Compositions>

[0121] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0122] <Preparation of photosensitive polyimide cured film>

[0123] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0124] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0125] Example 2

[0126] <Synthetic Intermediate 1 for Polyimide>

[0127] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 4.19 g of 3,3'-dihydroxybiphenyl diamine was added as an aromatic diamine monomer, and 0.19 g of 3-amino-4-hydroxybiphenyl was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 4.76 g of pyromellitic dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0128] <Preparation of modified polyimide resin>

[0129] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.28 g of allyl alcohol glycidyl ether as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction is complete, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction is complete, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1¹H NMR (CDCl₃): 1.66 (m, epoxide), 1.91–2.18 (m, epoxide), 2.45 (m, methylene hydrogen), 2.50 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.02–8.15 (m, aromatic ring hydrogen), 10.50 (s, phenolic hydroxyl hydrogen).

[0130] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=50.

[0131] <Preparation of Photosensitive Polyimide Resin Compositions>

[0132] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0133] <Preparation of photosensitive polyimide cured film>

[0134] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0135] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0136] Example 3

[0137] <Synthetic Intermediate 1 for Polyimide>

[0138] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 5.43 g of bis(3-amino-4-hydroxyphenyl) sulfone was added as an aromatic diamine monomer, and 0.167 g of o-amino-p-tert-butylphenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.42 g of biphenyltetracarboxylic dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0139] <Preparation of modified polyimide resin>

[0140] The above-mentioned polyimide intermediate 1 was dissolved in 40 mL of dry N-methylpyrrolidone. 4.12 g of 2-[[4-(2-propen-1-oxy)phenoxy]methyl]-ethylene oxide was added as an epoxy modifier, and 0.1 g of triethylamine was slowly added as a basic catalyst. The solution was heated to 70 °C and the reaction was continued for 12 h. After the reaction was completed, the solution was cooled to room temperature. 9 g of tert-butyldimethylchlorosilane was added dropwise to the cooled solution as a hydroxyl protecting agent, and the mixture was stirred for 30 min. The mixture was cooled to 5 °C, and 6.88 g of m-chloroperoxybenzoic acid was slowly added dropwise, and the mixture was stirred for 4 h. After the reaction was completed, 10.4 g of tetrabutylammonium fluoride was added to the mixture as a hydroxyl deprotecting agent, and the mixture was reacted at 25 °C for 2 h. The mixture was then slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a pale yellow flaky precipitate. The pale yellow flaky precipitate was filtered and dried to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.63 (m, epoxide), 1.88–2.12 (m, epoxide), 2.35 (m, methylene hydrogen), 2.52 (m, methylene hydrogen), 2.65 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 6.88–8.12 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0141] Tests showed that the modified polyimide resin contained 54% epoxy groups, and the degree of polymerization was n=50.

[0142] <Preparation of Photosensitive Polyimide Resin Compositions>

[0143] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0144] <Preparation of photosensitive polyimide cured film>

[0145] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0146] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0147] Example 4

[0148] <Synthetic Intermediate 1 for Polyimide>

[0149] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 4.46 g of 4,4-methylenebis(2-aminophenol) was added as an aromatic diamine monomer, and 0.215 g of 4-[2-(4-aminophenyl)diazepine]phenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 7.03 g of benzophenone tetracarboxylic dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0150] <Preparation of modified polyimide resin>

[0151] The above-mentioned polyimide intermediate 1 was dissolved in 40 mL of dry N-methylpyrrolidone. 3.80 g of 4-vinylbenzyl glycidyl ether was added as an epoxy modifier, and 0.1 g of triethylamine was slowly added as a basic catalyst. The solution was heated to 70 °C and the reaction was continued for 12 h. After the reaction was completed, the solution was cooled to room temperature. 9 g of tert-butyldimethylchlorosilane was added dropwise to the cooled solution as a hydroxyl protecting agent, and the mixture was stirred for 30 min. The mixture was cooled to 5 °C, and 6.88 g of m-chloroperoxybenzoic acid was slowly added dropwise, and the mixture was stirred for 4 h. After the reaction was completed, 10.4 g of tetrabutylammonium fluoride was added to the mixture as a hydroxyl deprotecting agent, and the mixture was reacted at 25 °C for 2 h. The mixture was then slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a pale yellow flaky precipitate. The pale yellow flaky precipitate was filtered and dried to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.67 (m, epoxide), 1.79-2.05 (m, epoxide), 2.33 (m, methylene hydrogen), 2.50 (m, methylene hydrogen), 2.71 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 6.95-8.14 (m, aromatic ring hydrogen), 10.52 (s, phenolic hydroxyl hydrogen). Testing showed that the modified polyimide resin contained 55% epoxy groups, with a degree of polymerization n = 45.

[0152] <Preparation of Photosensitive Polyimide Resin Compositions>

[0153] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0154] <Preparation of photosensitive polyimide cured film>

[0155] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0156] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0157] Example 5

[0158] <Synthetic Intermediate 1 for Polyimide>

[0159] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.07 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0160] <Preparation of modified polyimide resin>

[0161] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.27 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.33 (s, methyl hydrogen), 1.91–2.17 (m, epoxy hydrogen), 2.50 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.11–8.08 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0162] Tests showed that the modified polyimide resin contained 44% epoxy groups, and the degree of polymerization was n=70.

[0163] <Preparation of Photosensitive Polyimide Resin Compositions>

[0164] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0165] <Preparation of photosensitive polyimide cured film>

[0166] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0167] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0168] Example 6

[0169] <Synthetic Intermediate 1 for Polyimide>

[0170] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.07 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0171] <Preparation of modified polyimide resin>

[0172] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.30 (s, methyl hydrogen), 1.91–2.15 (m, epoxy hydrogen), 2.51 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.08–8.12 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0173] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=70.

[0174] <Preparation of Photosensitive Polyimide Resin Compositions>

[0175] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0176] <Preparation of photosensitive polyimide cured film>

[0177] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0178] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0179] Example 7

[0180] <Synthetic Intermediate 1 for Polyimide>

[0181] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.07 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0182] <Preparation of modified polyimide resin>

[0183] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 3.20 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction is complete, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction is complete, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.31 (s, methyl hydrogen), 1.91–2.12 (m, epoxy hydrogen), 2.54 (m, methylene hydrogen), 2.72 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.02–8.05 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0184] Tests showed that the modified polyimide resin contained 62% epoxy groups, and the degree of polymerization was n=70.

[0185] <Preparation of Photosensitive Polyimide Resin Compositions>

[0186] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0187] <Preparation of photosensitive polyimide cured film>

[0188] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0189] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0190] Example 8

[0191] <Synthetic Intermediate 1 for Polyimide>

[0192] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.07 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0193] <Preparation of modified polyimide resin>

[0194] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 3.51 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.33 (s, methyl hydrogen), 1.91–2.12 (m, epoxy hydrogen), 2.52 (m, methylene hydrogen), 2.72 (m, methylene hydrogen), 3.11 (s, tertiary hydrogen), 3.30 (m, alcohol hydroxyl hydrogen), 7.08–8.04 (m, aromatic ring hydrogen), 10.50 (s, phenolic hydroxyl hydrogen).

[0195] Tests showed that the modified polyimide resin contained 68% epoxy groups, and the degree of polymerization was n=70.

[0196] <Preparation of Photosensitive Polyimide Resin Compositions>

[0197] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0198] <Preparation of photosensitive polyimide cured film>

[0199] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0200] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0201] Example 9

[0202] <Synthetic Intermediate 1 for Polyimide>

[0203] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.07 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0204] <Preparation of modified polyimide resin>

[0205] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 3.97 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction is complete, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction is complete, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.33 (s, methyl hydrogen), 1.91–2.15 (m, epoxy hydrogen), 2.48 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.10–8.08 (m, aromatic ring hydrogen), 10.52 (s, phenolic hydroxyl hydrogen).

[0206] Tests showed that the modified polyimide resin contained 77% epoxy groups, and the degree of polymerization was n=70.

[0207] <Preparation of Photosensitive Polyimide Resin Compositions>

[0208] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0209] <Preparation of photosensitive polyimide cured film>

[0210] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0211] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0212] Example 10

[0213] <Synthetic Intermediate 1 for Polyimide>

[0214] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 7.20 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0215] <Preparation of modified polyimide resin>

[0216] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.30 (s, methyl hydrogen), 1.87–2.15 (m, epoxy hydrogen), 2.51 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.21 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.15–8.09 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0217] Tests showed that the modified polyimide resin contained 54% epoxy groups, and the degree of polymerization was n=10.

[0218] <Preparation of Photosensitive Polyimide Resin Compositions>

[0219] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0220] <Preparation of photosensitive polyimide cured film>

[0221] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0222] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0223] Example 11

[0224] <Synthetic Intermediate 1 for Polyimide>

[0225] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.95 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0226] <Preparation of modified polyimide resin>

[0227] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.33 (s, methyl hydrogen), 1.91–2.11 (m, epoxy hydrogen), 2.52 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.08–8.06 (m, aromatic ring hydrogen), 10.49 (s, phenolic hydroxyl hydrogen).

[0228] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=40.

[0229] <Preparation of Photosensitive Polyimide Resin Compositions>

[0230] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0231] <Preparation of photosensitive polyimide cured film>

[0232] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0233] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0234] Example 12

[0235] <Synthetic Intermediate 1 for Polyimide>

[0236] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.63 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0237] <Preparation of modified polyimide resin>

[0238] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.31 (s, methyl hydrogen), 1.88–2.18 (m, epoxy hydrogen), 2.51 (m, methylene hydrogen), 2.69 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.11–8.09 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0239] Tests showed that the modified polyimide resin contained 56% epoxy groups, and the degree of polymerization was n=70.

[0240] <Preparation of Photosensitive Polyimide Resin Compositions>

[0241] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0242] <Preparation of photosensitive polyimide cured film>

[0243] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0244] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0245] Example 13

[0246] <Synthetic Intermediate 1 for Polyimide>

[0247] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.45 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0248] <Preparation of modified polyimide resin>

[0249] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.32 (s, methyl hydrogen), 1.91–2.16 (m, epoxy hydrogen), 2.52 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.09–8.11 (m, aromatic ring hydrogen), 10.50 (s, phenolic hydroxyl hydrogen).

[0250] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=100.

[0251] <Preparation of Photosensitive Polyimide Resin Compositions>

[0252] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0253] <Preparation of photosensitive polyimide cured film>

[0254] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0255] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0256] Comparative Example 1

[0257] <Synthetic Intermediate 1 for Polyimide>

[0258] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0259] <Preparation of Unmodified Polyimide Resin>

[0260] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction is complete, cool to room temperature. Slowly add the mixed solution dropwise to deionized water under vigorous stirring, and a flaky precipitate forms. Filter and dry the pale yellow flaky precipitate to obtain unmodified polyimide resin. 1 ¹H NMR (CDCl₃): 2.01 (s, methyl hydrogen), 2.55 (m, methylene hydrogen), 2.72 (m, methylene hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 6.40–6.48 (m, ethylene hydrogen), 7.11–8.08 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0261] Tests showed that the degree of polymerization of the unmodified polyimide resin was n = 70.

[0262] <Preparation of Polyimide Resin Compositions>

[0263] Take 10g of the unmodified polyimide resin obtained in the previous step, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain the polyimide resin composition.

[0264] <Preparation of polyimide cured film>

[0265] 2.5 mL of the polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The wafer was then baked on a hot plate at 90°C for 150 seconds to set the polyimide resin composition. The set polyimide resin composition was then exposed to light at 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure.

[0266] Subsequently, a 2.38 wt% tetramethylammonium hydroxide aqueous solution was used as the developer, and deionized water was used as the cleaning solution. The three groups of dried silicon wafers were placed in a nitrogen atmosphere at 150°C, 200°C, and 350°C for 1 hour to cure, resulting in polyimide cured films.

[0267] Comparative Example 2

[0268] <Synthetic Intermediate 1 for Polyimide>

[0269] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0270] <Preparation of modified polyimide resin>

[0271] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 0.16 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.33 (s, methyl hydrogen), 1.90–2.18 (m, epoxy hydrogen), 2.50 (m, methylene hydrogen), 2.71 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.10–8.08 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0272] Tests showed that the modified polyimide resin contained 5% epoxy groups, and the degree of polymerization was n=70.

[0273] <Preparation of Photosensitive Polyimide Resin Compositions>

[0274] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0275] <Preparation of photosensitive polyimide cured film>

[0276] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0277] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0278] Comparative Example 3

[0279] <Synthetic Intermediate 1 for Polyimide>

[0280] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.11 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0281] <Preparation of modified polyimide resin>

[0282] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 0.66 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.31 (s, methyl hydrogen), 1.91–2.18 (m, epoxy hydrogen), 2.53 (m, methylene hydrogen), 2.72 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.11–8.10 (m, aromatic ring hydrogen), 10.52 (s, phenolic hydroxyl hydrogen).

[0283] Tests showed that the modified polyimide resin contained 20% epoxy groups, and the degree of polymerization was n=70.

[0284] <Preparation of Photosensitive Polyimide Resin Compositions>

[0285] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0286] <Preparation of photosensitive polyimide cured film>

[0287] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0288] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0289] Comparative Example 4

[0290] <Synthetic Intermediate 1 for Polyimide>

[0291] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.22 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0292] <Preparation of modified polyimide resin>

[0293] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.31 (s, methyl hydrogen), 1.91–2.18 (m, epoxy hydrogen), 2.51 (m, methylene hydrogen), 2.70 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.10–8.09 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0294] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=5.

[0295] <Preparation of Photosensitive Polyimide Resin Compositions>

[0296] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0297] <Preparation of photosensitive polyimide cured film>

[0298] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0299] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0300] Comparative Example 5

[0301] <Synthetic Intermediate 1 for Polyimide>

[0302] Nitrogen gas was bubbled into a 500 mL three-necked flask, and 40 mL of N-methylpyrrolidone was added. Then, 7.10 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added as an aromatic diamine monomer, and 0.02 g of p-aminophenol was added as a capping agent. After complete dissolution, the solution temperature was lowered to 10 °C, and 6.77 g of biphenyl ether dianhydride (aromatic dianhydride monomer) was added in three equal portions, with stirring continuously for 10 h. After the reaction was complete, a water separator and condenser were attached to the three-necked flask, and 10 g of xylene and 0.5 g of isoquinoline were added to the mixture. The solution was heated to approximately 185 °C until stable reflux occurred, and the reflux reaction was maintained for 4 h. After the reaction was complete, the solution was cooled to room temperature, and the solution was slowly added dropwise to vigorously stirred deionized water, resulting in the precipitation of a white flocculent precipitate. The precipitate was filtered and dried to obtain polyimide intermediate 1.

[0303] <Preparation of modified polyimide resin>

[0304] Dissolve the above-mentioned polyimide intermediate 1 in 40 mL of dry N-methylpyrrolidone, add 2.84 g of glycidyl methacrylate as an epoxy modifier, and slowly add 0.1 g of triethylamine as a basic catalyst. Heat the solution to 70 °C and react for 12 h. After the reaction, cool to room temperature. Add 9 g of tert-butyldimethylchlorosilane as a hydroxyl protecting agent to the cooled solution and stir for 30 min. Cool the mixed solution to 5 °C and slowly add 6.88 g of m-chloroperoxybenzoic acid while stirring for 4 h. After the reaction, add 10.4 g of tetrabutylammonium fluoride as a hydroxyl deprotecting agent to the mixed solution and react at 25 °C for 2 h. Slowly add the mixed solution to deionized water under vigorous stirring, and a pale yellow flaky precipitate will form. Filter and dry the pale yellow flaky precipitate to obtain a pale yellow powder, which is the modified polyimide resin. 1 ¹H NMR (CDCl₃): 1.31 (s, methyl hydrogen), 1.91–2.18 (m, epoxy hydrogen), 2.51 (m, methylene hydrogen), 2.69 (m, methylene hydrogen), 3.19 (s, tertiary hydrogen), 3.32 (m, alcohol hydroxyl hydrogen), 7.05–8.02 (m, aromatic ring hydrogen), 10.55 (s, phenolic hydroxyl hydrogen).

[0305] Tests showed that the modified polyimide resin contained 55% epoxy groups, and the degree of polymerization was n=150.

[0306] <Preparation of Photosensitive Polyimide Resin Compositions>

[0307] Take 10g of the modified polyimide resin obtained in the above steps, dissolve it in 25mL of N-methylpyrrolidone, and add 0.2g of 9-anthracene methyl ester piperidine-1-carboxylic acid tert-butyl ester and 0.02g of resorcinol diglycidyl ether while stirring under light-protected conditions to obtain a photosensitive polyimide resin composition that can be cured at low temperature.

[0308] <Preparation of photosensitive polyimide cured film>

[0309] 2.5 mL of the photosensitive polyimide resin composition was dropped onto a 6-inch silicon wafer and coated by spin coating at 3000 rpm. The mixture was then baked on a hot plate at 90°C for 150 seconds to set the photosensitive polyimide resin composition. The set photosensitive polyimide resin composition was then exposed to 200 mJ / cm² using an I-line exposure machine. 2 Exposure is performed, and different sized masks are used to control the light source during exposure, so that the photosensitive polyimide resin composition can present patterns of different sizes after curing.

[0310] Subsequently, the photolithographic pattern was obtained by using a 2.38 wt% tetramethylammonium hydroxide aqueous solution as the developer and deionized water as the cleaning solution. Three sets of dried silicone sheets with photolithographic patterns were then cured at 150°C, 200°C, and 350°C under a nitrogen atmosphere for 1 hour, respectively, to obtain a photosensitive polyimide cured film with a photolithographic pattern formed by curing the photosensitive polyimide resin composition.

[0311] The relevant performance tests for each embodiment and each comparative example are shown in Table 1.

[0312] Table 1

[0313]

[0314]

[0315] As can be seen from Examples 1 to 13 and Comparative Examples 1 to 5, using the preparation method of this application, by reacting aromatic diamine monomers, end-capping agents and aromatic dianhydride monomers, and adding xylene and isoquinoline, polyimide intermediate 1 is obtained; then, highly active epoxy functional groups are introduced into polyimide intermediate 1 to obtain modified polyimide resin, which has both the low-temperature curing characteristics of epoxy resin and the high-temperature stability, mechanical properties and chemical resistance of polyimide resin, thus reducing the curing temperature of the photosensitive polyimide resin composition, so that the photosensitive polyimide cured film can be obtained by low-temperature curing and has better thermal stability and chemical resistance.

[0316] The types of aromatic diamine monomers, aromatic dianhydride monomers, end-capping agents, and epoxy modifiers affect the performance of photosensitive polyimide cured films. As can be seen from Examples 1 to 4, the modified polyimide resin prepared using aromatic diamine monomers, aromatic dianhydride monomers, end-capping agents, and epoxy modifiers within the scope of this application can be cured at low temperatures (200°C). The resulting photosensitive polyimide cured films exhibit good resolution, a low coefficient of thermal expansion, a high curing rate, high tensile strength, a high Young's modulus, a high elongation at break, and a low film removal rate. This indicates that the photosensitive polyimide cured films possess excellent low-temperature curing characteristics, high-temperature stability, mechanical properties, and chemical resistance.

[0317] The substitution ratio of epoxy groups affects the curing rate of the modified polyimide resin, thereby affecting the resolution and film removal rate of the photosensitive polyimide cured film. As can be seen from Examples 5 to 9, by controlling the substitution ratio of epoxy groups within the range specified in this application, the modified polyimide resin can be cured at low temperature (200℃), and the resulting photosensitive polyimide cured film has good resolution and a low film removal rate. Simultaneously, the photosensitive polyimide cured film exhibits a low coefficient of thermal expansion, high tensile strength, Young's modulus, and elongation at break, indicating that the photosensitive polyimide cured film possesses excellent low-temperature curing characteristics, high-temperature stability, mechanical properties, and chemical resistance.

[0318] The degree of polymerization affects the mechanical strength and film removal rate of the photosensitive polyimide cured film. As can be seen from Examples 10 to 13, by controlling the degree of polymerization within the range specified in this application, the modified polyimide resin can be cured at low temperature (200°C). The resulting photosensitive polyimide cured film exhibits good resolution, high tensile strength, and low film removal rate. Simultaneously, the prepared photosensitive polyimide cured film possesses a low coefficient of thermal expansion, a high Young's modulus, and a high elongation at break, indicating that the photosensitive polyimide cured film has excellent low-temperature curing characteristics, high-temperature stability, mechanical properties, and chemical resistance.

[0319] As shown in Comparative Example 1, using unmodified polyimide resin, the unmodified polyimide resin cannot form a cross-linked structure, resulting in a film with poor mechanical strength and resolution. Comparative Examples 2 and 3 show that the substitution ratio of epoxy groups is lower than the range of this application, leading to a lower curing rate of the modified polyimide resin at 200℃ and poor resolution of the prepared photosensitive polyimide cured film. Comparative Example 4 shows that the degree of polymerization of the modified polyimide resin is lower than the range of this application, resulting in lower tensile strength, Young's modulus, and elongation at break of the photosensitive polyimide cured film. Comparative Example 5 shows that the degree of polymerization of the modified polyimide resin is higher than the range of this application, resulting in a lower curing rate of the modified polyimide resin at 200℃, poorer resolution of the prepared photosensitive polyimide cured film, and a higher film removal rate. The above results indicate that photosensitive polyimide curing films prepared from unmodified polyimide resin or modified polyimide resin containing epoxy groups whose substitution ratio and degree of polymerization are not within the scope of this application cannot simultaneously possess good low-temperature curing characteristics, high-temperature stability, mechanical properties, and chemical resistance.

[0320] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A modified polyimide resin, wherein the structure of the modified polyimide resin is shown in Formula 1. in, Ar1 is selected from Selected from Ar3 is selected from The hydroxyl groups in the modified polyimide resin are replaced by epoxy-containing groups, with a substitution ratio of 40% to 80%; the epoxy-containing groups are selected from... The degree of polymerization n of the modified polyimide resin satisfies: 10 ≤ n ≤ 100.

2. The modified polyimide resin according to claim 1, wherein, The substitution ratio is 60% to 80%.

3. A photosensitive polyimide resin composition comprising the modified polyimide resin according to any one of claims 1 to 2, an organic solvent, and additives; in, The organic solvent is selected from at least one of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, γ-butyrolactone, γ-valerolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, ethyl lactate, and dimethylimidazolinone; the additives include photo-induced alkalization agents and stabilizers, and the solid content of the photosensitive polyimide composition is 20% to 40%.

4. The photosensitive polyimide resin composition according to claim 3, wherein, The photo-induced alkali-producing agent is selected from at least one of 9-anthramethylpiperidin-1-carboxylate, 9-anthramethyl N,N-diethylcarbamate, 1-(anthraquinone-2-yl)ethylimidazol-1-carboxylic acid, cyclohexyl-2-(3-benzoylphenyl)propionic acid, and guanidino-2-(3-benzoylphenyl)propionic acid; the stabilizer is selected from at least one of resorcinol diglycidyl ether, p-methoxyphenol, p-dinitrobenzene, 2,5-methylbenzoquinone, and p-benzylaminophenol; based on the total mass of the photosensitive polyimide composition, the modified polyimide resin has a mass percentage of 15% to 40%, the photo-induced alkali-producing agent has a mass percentage of 0.5% to 4%, and the stabilizer has a mass percentage of 0.1% to 0.5%.

5. A photosensitive polyimide cured film, which is cured from the photosensitive polyimide resin composition according to any one of claims 3 to 4.

6. The photosensitive polyimide cured film according to claim 5, wherein, The curing temperature of the photosensitive polyimide curing film is ≤200℃.

7. A method for preparing the modified polyimide resin according to any one of claims 1 to 2, wherein, The preparation method includes the following steps: (1) Dissolve the aromatic diamine monomer in a high-boiling-point polar organic solvent, and add the capping agent and aromatic dianhydride monomer in sequence to react and obtain a capped polyamic acid solution; the boiling point of the high-boiling-point polar organic solvent is 150℃~250℃; (2) Add xylene and isoquinoline to the polyamic acid solution and heat under reflux to obtain a polyimide intermediate 1 solution; (3) Add the polyimide intermediate 1 solution to deionized water, stir, filter and dry to obtain polyimide intermediate 1; (4) The polyimide intermediate 1 is dissolved in a high-boiling-point polar organic solvent, an epoxy modifier and an alkaline catalyst are added, and the modified intermediate 2 solution is obtained after the reaction; the boiling point of the high-boiling-point polar organic solvent is 150℃~250℃. (5) Add a hydroxyl protecting agent to the modified intermediate 2 solution and react to obtain the modified intermediate 3 solution; (6) Cool the modified intermediate 3 solution to 0-20°C and add peroxy acid to it to obtain a modified intermediate 4 solution with epoxy group end group; (7) Add a hydroxyl deprotecting agent dropwise to the solution of the modified intermediate 4, the reaction temperature is 20-50℃, the reaction time is 2-6 hours, and a polyimide solution with epoxy groups is obtained; (8) The polyimide solution with epoxy groups is added to deionized water, stirred, and flocculent precipitate is formed. The precipitate is filtered and dried to obtain modified polyimide resin.

8. The preparation method according to claim 5, wherein, The high-boiling-point polar organic solvent is selected from at least one of N-methylpyrrolidone, N-ethylpyrrolidone, dimethylacetamide, γ-butyrolactone, γ-valerolactone, cyclohexanone, cyclopentanone, propylene glycol monomethyl ether acetate, dimethyl sulfoxide, ethyl lactate, and dimethylimidazolinone; the aromatic dianhydride monomer is selected from at least one of biphenyl ether dianhydride, pyromellitic dianhydride, biphenyltetracarboxylic dianhydride, 4,4'-terephthalodioxydiphthalic anhydride, and benzophenone tetracarboxylic dianhydride. The aromatic diamine monomer is selected from at least one of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 3,3'-dihydroxybenzidine, 4,4-methylenebis(2-aminophenol), 2,2-bis(3-amino-4-hydroxyphenyl)propane, and bis(3-amino-4-hydroxyphenyl)sulfone; the molar ratio of the aromatic dianhydride monomer to the aromatic diamine monomer is 1.01 to 1.15:1, preferably 1.01 to 1.05:1; The end-capping agent is selected from at least one of p-aminophenol, 4-[2-(4-aminophenyl)diazepine]phenol, o-amino-p-cresol, 3-amino-4-hydroxybiphenyl, 2-amino-4,5-dimethylphenol, and o-amino-p-tert-butylphenol, and the molar ratio of the end-capping agent to the aromatic diamine monomer is 0.01 to 0.1:

1.

9. The preparation method according to claim 5, wherein, The epoxy modifier in step (4) is selected from at least one of glycidyl methacrylate, allyl glycidyl ether, 2-[[4-(2-propen-1-oxy)phenoxy]methyl]-ethylene oxide and 4-vinylbenzyl glycidyl ether, and the alkaline catalyst is selected from at least one of triethylamine, butylamine, isopropylamine, sodium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene and pyridine; The molar ratio of the epoxy modifier to the aromatic dianhydride monomer is 0.5 to 3:1, and the molar ratio of the alkaline catalyst to the aromatic dianhydride monomer is 0.03 to 0.3:

1.

10. The preparation method according to claim 5, wherein, The hydroxyl protectant in step (5) is selected from at least one of tert-butyldimethylchlorosilane, benzyl isopropenyl ether and triphenylchloromethane, and the molar ratio of the hydroxyl protectant to the aromatic dianhydride monomer is 0.5 to 3:

1.

11. The preparation method according to claim 5, wherein, The peroxy acid in step (6) is selected from at least one of peroxyformic acid, peracetic acid, peroxybenzoic acid, m-chloroperoxybenzoic acid and peroxytrifluoroacetic acid, and the molar ratio of the peroxy acid to the aromatic dianhydride monomer is 1.5 to 3:

1.

12. The preparation method according to claim 5, wherein, The hydroxyl deprotecting agent in step (7) is selected from at least one of acetic acid, potassium carbonate, tetra(trifluoromethanesulfonic acid) hafnium, lithium acetate, 1,8-diazabicyclo(5,4,0)-7-undecene and tetrabutylammonium fluoride, and the molar ratio of the hydroxyl deprotecting agent to the aromatic dianhydride monomer is 1.5 to 3.5:1.

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