Photosensitive polyimide precursor, preparation method thereof, composition and film

Abstract

The invention discloses a photosensitive polyimide precursor, a preparation method thereof, a composition and a film, the photosensitive polyimide precursor is formed by polymerizing a core diamine monomer, an auxiliary diamine monomer and a tetracarboxylic dianhydride monomer, the core diamine monomer is a hydroxyl-containing spiro / fluorene ring diamine compound, and the ratio of the core diamine monomer to (the core diamine monomer + the auxiliary diamine monomer) is 0.1-1; the ratio of the core diamine monomer to the auxiliary diamine monomer to the tetracarboxylic dianhydride monomer is (0.7-1.1): 1; in the scheme, a core diamine monomer structure simultaneously contains hydroxyl and a spiro / fluorene ring skeleton, the hydroxyl can improve the alkali solubility and the photosensitive synergism, and the spiro / fluorene ring structure inhibits molecular chain accumulation through a steric hindrance effect and gives consideration to both solubility and thermal stability; the hydroxyl group and the spiro / fluorene ring structure can achieve a synergistic effect, and the technical bottleneck that solubility, thermal stability and photosensitivity of a fluorine-free system are difficult to consider at the same time is broken through.

Description

Technical Field

[0001] This invention relates to a photosensitive polyimide precursor, its preparation method, composition, and film, belonging to the field of photosensitive resin materials. Background Technology

[0002] Photosensitive polyimide, as a core material for preparing patterned films in photolithography, has become an indispensable key material in high-end electronic fields such as microelectronic packaging, flexible displays, and semiconductor passivation due to its combination of photosensitive processability and the inherent excellent properties of polyimide.

[0003] There are significant differences and limitations in the current mainstream optimization paths for photosensitive polyimide performance: On the one hand, traditional fluorinated photosensitive polyimide precursors, by introducing fluorinated groups, can improve the solubility and photosensitivity of the material in organic solvents. However, the synthesis route of fluorinated monomers is complex and difficult to purify, resulting in high raw material costs. Moreover, fluorinated materials are prone to releasing toxic and harmful fluorinated byproducts during processing, which are difficult to degrade naturally after disposal, posing a potential threat to the ecological environment and seriously contradicting the industry trend of green manufacturing and low-carbon development. On the other hand, while existing fluorine-free photosensitive polyimide precursors avoid the environmental and cost problems of fluorinated systems, they face multiple performance bottlenecks. Their molecular chains are rigid and the polar groups are unevenly distributed, resulting in low dissolution rate in alkaline developers, poor photosensitivity, low development tolerance, and poor thermal stability and mechanical properties of the developed pattern. In the existing technology, attempts to modify fluorine-free resin precursors have failed to achieve synergistic performance optimization: while introducing hydroxyl groups into the precursor can improve alkali solubility, it leads to a significant decrease in thermal stability; while introducing aliphatic segments can improve solubility, it sacrifices the mechanical strength and chemical corrosion resistance of the film; while introducing resin precursors with large-volume / non-coplanar side groups can improve thermal stability and rigidity, the problems of insufficient alkali solubility and slow photosensitivity response have not been fundamentally solved, and they still cannot meet the requirements of high-end electronic devices for the comprehensive performance of materials.

[0004] Therefore, developing a technology that can simultaneously achieve high solubility, high-precision photosensitive development performance, high resolution, and environmental friendliness has become an urgent direction to break through current technological bottlenecks and meet the development needs of the high-end electronics field. Summary of the Invention

[0005] The purpose of this invention is to provide a photosensitive polyimide precursor and its composition to solve the above-mentioned problems.

[0006] The technical solution to achieve the purpose of this invention is: a photosensitive polyimide precursor, characterized in that: it is polymerized from a core diamine monomer, an auxiliary diamine monomer and a tetracarboxylic dianhydride monomer, wherein the core diamine monomer is a hydroxyl-containing spiro / fluorene ring diamine compound, and the ratio of core diamine monomer to (core diamine monomer + auxiliary diamine monomer) is 0.1~1; and the ratio of (core diamine monomer + auxiliary diamine monomer) to tetracarboxylic dianhydride monomer is (0.7~1.1):1.

[0007] In the aforementioned photosensitive polyimide precursor, the core diamine monomer structure contains both hydroxyl (~OH) and spiro / fluorene ring skeletons. The hydroxyl group can enhance alkali solubility and photosensitivity synergy, while the spiro / fluorene ring structure inhibits molecular chain stacking through steric hindrance, thus balancing solubility and thermal stability.

[0008] Furthermore, in order to adjust the thermal, mechanical, electrical and processing properties of the photosensitive polyimide precursor, its molecular weight is controlled to be 2000~100000 according to performance requirements.

[0009] Furthermore, the core diamine monomer is , One or more of the following: Specifically, when the hydroxyl group is located at the end of the side chain, it can reduce the interference with the stability of the main chain and maintain the surface alkali solubility. When there are too many hydroxyl groups, the thermal stability is poor and the film is prone to cracking under high temperature baking after preparation. When the hydroxyl group is too low, it will cause development difficulties and increase the residue. In terms of specific ratio, 0.8–1.6 mmol / g of hydroxyl group and 20–40 mol% of spiro / fluorene are preferred.

[0010] Furthermore, depending on the different performance requirements of the polyimide precursor for different applications, the auxiliary diamine monomer is selected from one or more combinations of p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl], 2,2-bis[3-(3-aminobenzoylamino)-4-hydroxyphenyl]propane, 1,4-bis(aminophenoxy)benzene, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, and bis(4-aminophenyl)tetramethyldisiloxane.

[0011] Furthermore, based on the different requirements for thermal performance, mechanical properties, dielectric properties, solubility, transparency, and processability in different application scenarios, the tetracarboxylic dianhydride monomer is selected from one or more of the following aromatic / alicyclic tetracarboxylic dianhydrides: pyromellitic dianhydride, biphenyl dianhydride, diphenyl ether dianhydride, bisphenol A type diether dianhydride, benzophenone dianhydride, 4,4'-(4,4'-isopropyldiphenoxy) bisphthalic anhydride, hydrogenated pyromellitic dianhydride, bicyclo[2.2.2]octyl-7-ene-2,3,5,6-tetracarboxylic dianhydride, hydrogenated biphenyl dianhydride, norbornene-2,3,5,6-tetracarboxylic dianhydride. The diamine monomer (core diamine + ...) is selected from these. The molar ratio of auxiliary diamine to tetracarboxylic acid dianhydride monomer is controlled at 0.7~1.1:1, preferably 0.8~0.9:1. A slight excess of anhydride monomer ensures sufficient molecular chain growth while avoiding performance fluctuations caused by excessive amino groups.

[0012] Furthermore, this application also relates to the polymerization process of the above-mentioned photosensitive polyimide precursor, including the following steps: S1 Preparation of polyamic acid solution: Diamine monomer is added to a polar organic solvent to form a monomer solution; then tetracarboxylic acid dianhydride monomer is slowly added to the monomer solution, and the reaction is carried out at a constant temperature to obtain polyamic acid solution; S2 Preparation of polyimide resin precursor: Add end-capping agent to polyamic acid solution and react, then add esterification reagent and react.

[0013] In step S1, the feeding rate needs to be controlled to avoid uneven reaction caused by excessively high local temperatures; The polar organic solvent is selected from one or more mixed solvents selected from N-methylpyrrolidone, dimethylformamide, dimethylacetamide, γ-butyrolactone, propylene glycol methyl ether, and ethyl lactate.

[0014] Furthermore, in order to control the molecular weight of the reactants, regulate the end structure and polarity of the molecular chains, and further optimize the photosensitivity and development tolerance of the precursors, the reaction temperature in step S1 is 20~60℃, the reaction time is 4~8h, and the solid content of the reaction is controlled at 10~35wt%; in step S2, the reaction time of the end-capping agent is 1~4h, and the reaction time of the esterification reagent is 30~120min.

[0015] Furthermore, this application also relates to a polyimide composition prepared using the aforementioned photosensitive polyimide precursor, the composition of which is as follows: 5-40 parts of photosensitive polyimide precursor, 1-5 parts of photosensitizer, 1-5 parts of crosslinking agent, 0.2-2 parts of sensitizer, and 50-90 parts of organic solvent. The spiro / fluorene-containing fluorine-free photosensitive polyimide precursor serves as the core film-forming substrate, the photosensitizer provides the core response function for positive photosensitivity, the sensitizer enhances the photosensitizer's photoresponse sensitivity and broadens the exposure dose window, and the organic solvent serves as the dispersion medium, synergistically compatible with the polar organic solvent used in the precursor preparation to ensure the uniformity and stability of the composition system.

[0016] During preparation, the spiro / fluorene ring-containing fluorine-free photosensitive polyimide precursor, photosensitive agent, crosslinking agent, and sensitizer are added to an organic solvent in a specific ratio. The solvent is stirred at room temperature or under elevated temperature until completely dissolved to form a uniform and transparent composition solution. This ensures that the components work synergistically and that there are no obvious particles or layering phenomena, thus meeting the requirements of photolithography for system uniformity.

[0017] Furthermore, in the above-mentioned polyimide composition, the photosensitizer is selected from one or more photoacid-producing agents such as diazonium quinone compounds, oxime sulfonate compounds, sulfonium salts, phosphonium salts, diazonium salts, and iodonium salts; the crosslinking agent is selected from one or more combinations of 4-methoxy-2,6-dimethylphenol, 3,4,5-trimethoxyphenol, 4,4'-dimethoxybiphenyl, 3,4,5-trimethoxyphenol, 1,1,1-tris[(2,6-dimethoxymethyl-4-hydroxy)phenyl]ethane, 4-ethyl-2-methoxyphenol, 2-methoxy-6-methylphenol, 3,3',5,5'-tetramethoxy-4,4'-dihydroxybiphenyl, and 4-methoxytriphenylmethyl alcohol; the sensitizer is 0.2-2 parts, selected from 4- One or more of the following are used: chlorophenol, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl)methane, 2,6-dichlorophenol, 1,1,1-tris(4-hydroxyphenyl)ethane, 2-bromophenol, and 2,4,6-tribromophenol, with the specific formulation adjusted according to performance requirements. This polyimide composition significantly improves process performance through careful selection and proportioning of photosensitizers, crosslinking agents, and sensitizers: the photosensitizers include diazonaphthoquinones and various photoacid-producing agents (such as sulfonium salts and iodonium salts), adapting to different exposure wavelengths and positive imaging requirements; the crosslinking agent uses polyhydroxy / methoxy aromatic compounds, which can be controllably crosslinked during thermosetting, enhancing the developability of unexposed areas without sacrificing film toughness; the sensitizer uses specific substituted phenols, effectively broadening the absorption range of the photosensitizer, improving photoresponse efficiency, reducing exposure dose, and improving the roughness of the pattern edges. The synergistic effect of these three components gives the composition high sensitivity, high contrast, wide process window, and excellent development stability, making it suitable for high-resolution, high-yield one-step lithography processes.

[0018] This application also relates to a polyimide film prepared using the aforementioned polyimide composition.

[0019] Specifically, the above composition is used to prepare microelectronic packaging insulating layers, flexible display substrate pixel definition layers, or semiconductor passivation layers. The specific application process is as follows: Coating: The composition is coated onto the surface of a substrate by conventional methods such as spin coating or slot coating. The substrate may be a silicon wafer, a glass substrate, or a flexible polymer film. HVCD: The prepared photosensitive polyimide wet film is dried under high vacuum to remove most of the solvent; Pre-baking: After coating, pre-baking at a low temperature removes some organic solvents and forms a preliminary dry film; Exposure: Patterned exposure is performed using light sources such as ultraviolet light through a mask. The photosensitizer produces acid under light, which triggers a bridging reaction and changes in the precursor structure. Development: The composition in the exposed areas is removed using an alkaline developer, while the unexposed areas are preserved to form the pattern. The alkalinity of the precursor and the photoresponse of the photosensitive agent are combined to ensure that the edges of the pattern are clear. Post-baking: After development, high-temperature post-baking is performed to complete imidization and cross-linking curing, forming the final patterned film layer, which has excellent thermal stability, mechanical properties and insulation properties.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The core diamine monomer structure of the present invention contains both hydroxyl and spiro / fluorene ring skeletons. The hydroxyl group can improve alkali solubility and photosensitivity synergy, and the spiro / fluorene ring structure inhibits molecular chain stacking through steric hindrance effect, thus taking into account both solubility and thermal stability. The hydroxyl group and the spiro / fluorene ring structure can work together to overcome the technical bottleneck that it is difficult to take into account the solubility, thermal stability and photosensitivity of fluorine-free systems.

[0021] (2) The present invention controls the molecular weight of polyimide precursor by different diamine monomer structures, thereby controlling its thermal, mechanical, electrical and processing properties.

[0022] (3) The present invention controls the thermal stability and development performance of polyimide precursor by selecting the structure of the core diamine monomer and the auxiliary diamine monomer. The scheme is highly flexible and has a wide range of options.

[0023] (4) The present invention ensures sufficient growth of molecular chains by using a slightly excessive amount of acid anhydride monomers, while avoiding performance fluctuations caused by excessive amino groups.

[0024] (5) The present invention also relates to a simple polymerization process for photosensitive polyimide precursors, and the precursors prepared by this method have both processing fluidity and film-forming properties.

[0025] (6) This invention controls the molecular weight of the reactants by controlling the reaction conditions, and regulates the structure and polarity of the molecular chain ends, thereby further optimizing the photosensitivity and development tolerance of the precursor.

[0026] (7) This invention relates to a polyimide composition, which uses a fluorine-free photosensitive polyimide precursor containing spiro / fluorene rings as the core film-forming substrate, and has excellent thermal stability, high transparency and good solubility; by rationally proportioning photosensitizer, sensitizer and crosslinking agent, the photosensitivity, development contrast and pattern fidelity are significantly improved, while the exposure process window is widened; with the use of a compatible organic solvent system, the composition is ensured to be uniform and stable, and the film is dense and defect-free, which is suitable for one-step photolithography processes in flexible electronics, advanced packaging and other fields, and has high performance, environmental protection and process simplicity.

[0027] (8) The polyimide composition of the present invention achieves synergistic effect of components by carefully selecting the types and ratios of photosensitizers, crosslinking agents and sensitizers, so that the composition has high sensitivity, high contrast, wide process window and excellent development stability, and is suitable for high-resolution, high-yield one-step photolithography process.

[0028] (9) The present invention also relates to a polyimide film that has excellent thermal stability, high insulation, good mechanical strength and flexibility. Thanks to the synergistic design of the fluorine-free precursor containing spiro / fluorene rings and the photosensitive system, the film pattern has clear edges, high resolution and no residue, and no additional photoresist layer is required, simplifying the process. It is suitable for high-end application scenarios such as microelectronic packaging insulating layer, flexible display pixel definition layer and semiconductor passivation layer, meeting the requirements of high reliability, high yield and green manufacturing. Detailed Implementation

[0029] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with specific implementation methods.

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0031] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0032] The technical solutions of the synthetic examples, embodiments, and comparative examples of the present invention will be clearly and completely described below. It is obvious that the described synthetic examples, embodiments, and comparative examples are only a part of the present invention, and not all of the synthetic examples, embodiments, and comparative examples.

[0033] The testing methods for the synthetic examples, exemplary examples, and comparative examples are as follows: Film loss test: The film thickness of the photosensitive polyimide resin after soft baking, development and curing was measured using a film thickness gauge (FILMMETRICS F50). Film loss (1min) FL = thickness before development - thickness after development. Film retention rate test: Film retention rate Rw (%) = (thickness after development) / (thickness after soft baking) * 100%; Cured film retention rate RCw (%) = Cured film thickness / Thickness after soft baking * 100% Sensitivity Testing: A 3μm thick pre-softened film of photosensitive polyimide resin was prepared on a silicon wafer using a spin coater. An ABM / 6 / 350 exposure machine was used to expose the pre-softened film. After exposure, a DEV-150 developing machine was used with a 2.38% tetramethylammonium hydroxide aqueous solution as the developer for 1 minute. The film was then rinsed with purified water and dried. The minimum exposure time at which the exposed area completely dissolved and successfully formed a clear pattern is the photosensitivity of the photosensitive polyimide resin.

[0034] Resolution: The pre-softened film was exposed on an ABM / 6 / 350 exposure unit, followed by development using a DEV-150 developing unit with a 2.38% tetramethylammonium hydroxide aqueous solution for 1 minute. It was then rinsed with purified water and dried. The film was then observed using an OLYMPUS MX51 optical microscope, and the smallest dimension of the lines and patterns obtained without residue was taken as the resolution.

[0035] Preparation method of cured film: The photosensitive polyimide composition is selected on the glass substrate, and then pre-softened at 120℃ for 2 min by HVCD for 2 min; then the film is transferred to a high temperature oven, heated to 260℃ under nitrogen atmosphere, and kept at the temperature for 1 h. After the oven cools to room temperature, the sample is taken out, soaked in deionized water for peeling, and then dried at 100℃ for 12 h in a vacuum drying oven.

[0036] Performance testing: Optical performance: The cured film thickness is approximately 3μm. The optical transmittance Y and chromaticity b* values ​​of the cured film were measured using a Hunterlab Ultra Scan Vis photometer and corrected with a standard white board. Dielectric properties: The dielectric constant Dk and dielectric loss Df of the cured film at 1 kHz were tested using a broadband dielectric impedance spectrometer, Novocontrol Alpha-A.

[0037] Heat resistance test: The glass transition temperature of the cured film was tested using a differential scanning calorimeter (DSC TA Q200). The film was first heated to 300℃ and held for 10 minutes for annealing. Then it was slowly cooled to room temperature and then heated to 350℃ again. The glass transition temperature Tg in the second heating curve was read. Cross-cut adhesion test: Tests the adhesion of the cured film to glass and silicon wafers; Synthesis Example 1: Synthesis of fluorine-free photosensitive polyimide precursor A1 containing spiro / fluorene rings In a nitrogen-protected 500 mL reaction vessel, 0.10 mol of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added to 400 g of N-methylpyrrolidone (NMP) and stirred at room temperature for 30 min until completely dissolved. Then, 0.07 mol of hydroxyl-containing spiro / fluorene diamine and 0.02 mol of 4,4'-diaminodiphenyl ether were added to the system, and the feed port was rinsed with 100 g of NMP. The temperature was raised to 50 °C and the reaction was maintained at this temperature for 4 h. Subsequently, 0.03 mol of 4-aminophenol was added as a capping agent, and the mixture was rinsed with 5 g of NMP and the reaction was continued at 50 °C for 2 h. Finally, 0.2 mol of n,n-dimethylformamide diethyl acetal was added, and the reaction was carried out for 1 h. After the reaction was completed and cooled to room temperature, the reaction solution was poured into 3L of deionized water under stirring in a thin stream, and a white precipitate was formed. The precipitate was collected by filtration, washed three times with deionized water, and dried in a vacuum oven at 80℃ for 24h to obtain fluorine-free photosensitive polyimide precursor A1.

[0038] Synthesis Example 2: Synthesis of fluorine-free photosensitive polyimide precursor A2 containing spiro / fluorene rings In a 500 mL reaction vessel under a nitrogen atmosphere, 0.08 mol of 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride was added to 300 g of dimethylacetamide (DMAc) and stirred to dissolve. 0.05 mol of hydroxyl-containing spiro / fluorene diamine and 0.03 mol of 1,4-bis(aminophenoxy)benzene were added, and the mixture was washed with 80 g of DMAc. The mixture was heated to 55 °C and reacted for 5 h. 0.02 mol of 4-aminophenol was added for end-capping, and the reaction continued for 2 h. Then, 0.2 mol of n,n-dimethylformamide diethyl acetal was added, and the reaction was carried out for 1 h. After cooling to room temperature, the precipitate was poured into 3 L of deionized water, filtered and washed three times, and dried under vacuum at 80 °C for 24 h to obtain fluorine-free photosensitive polyimide precursor A2.

[0039] Synthesis Example 3: Synthesis of fluorine-free photosensitive polyimide precursor A3 containing spiro / fluorene rings In a nitrogen-protected 500 mL reaction vessel, 0.10 mol of norbornene-2,3,5,6-tetracarboxylic dianhydride was added to 400 g of NMP and stirred to dissolve. 0.08 mol of hydroxyl-containing spiro / fluorene diamine and 0.01 mol of 2,2-bis[3-(3-aminobenzoylamino)-4-hydroxyphenyl]propane were added, and the mixture was washed with 100 g of NMP. The mixture was heated to 60 °C and reacted for 6 h. 0.04 mol of 4-aminophenol was added for end-capping, and the mixture was reacted for 2 h. Then, 0.2 mol of n,n-dimethylformamide diethyl acetal was added, and the mixture was reacted for 1 h. After cooling, the precipitate was poured into 3 L of deionized water, filtered, washed three times, and dried under vacuum at 80 °C for 24 h to obtain fluorine-free photosensitive polyimide precursor resin A3.

[0040] Comparative Synthesis Example 1 In a nitrogen-protected 500 mL reaction vessel, 0.10 mol of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added to 400 g of N-methylpyrrolidone (NMP), and the mixture was stirred at room temperature for 30 min until completely dissolved. Then, 0.09 mol of 4,4'-diaminodiphenyl ether was added to the system, and the feed port was rinsed with 100 g of NMP. The temperature was raised to 50 °C and the reaction was maintained at this temperature for 4 h. Subsequently, 0.03 mol of 4-aminophenol was added as a capping agent, and the mixture was rinsed with 5 g of NMP and the reaction was continued at 50 °C for 2 h. Finally, 0.2 mol of n,n-dimethylformamide diethyl acetal was added, and the reaction was continued for 1 h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was poured into 3 L of stirred deionized water in a thin stream. This solution was labeled as fluorine-free alkali-soluble resin B1.

[0041] Comparative Synthesis Example 2 In a 500 mL reaction vessel under a nitrogen atmosphere, 0.08 mol of 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride was added to 300 g of dimethylacetamide (DMAc) and stirred until dissolved. 0.08 mol of 1,4-bis(aminophenoxy)benzene was added, and the mixture was washed with 80 g of DMAc. The mixture was heated to 55 °C and reacted for 5 h. 0.02 mol of 4-aminophenol was added to cap the reaction, and the reaction continued for 2 h. Then, 0.2 mol of n,n-dimethylformamide diethyl acetal was added, and the reaction was carried out for 1 h. After cooling to room temperature, the precipitate was poured into 3 L of deionized water, filtered, washed three times, and dried under vacuum at 80 °C for 24 h to obtain fluorine-free alkali-soluble resin B2.

[0042] Comparative Synthesis Example 3 In a nitrogen-protected 500 mL reaction vessel, 0.10 mol of norbornene-2,3,5,6-tetracarboxylic dianhydride was added to 400 g of NMP and stirred to dissolve. 0.09 mol of 2,2-bis[3-(3-aminobenzoylamino)-4-hydroxyphenyl]propane was added, and the mixture was washed with 100 g of NMP. The mixture was heated to 60 °C and reacted for 6 h. 0.04 mol of 4-aminophenol was added for end-capping, and the reaction was continued for 2 h. Then, 0.2 mol of n,n-dimethylformamide diethyl acetal was added, and the reaction was continued for 1 h. After cooling, the precipitate was poured into 3 L of deionized water, filtered, washed three times, and dried under vacuum at 80 °C for 24 h to obtain fluorine-free alkali-soluble resin B3.

[0043] Implementation Cases Example 1, composition formulation: 10g of fluorine-free polyimide resin precursor A1, 2.1g of 2,3,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (3,5-dimethoxyphenol), 0.9g of cosolvent (2,6-dichlorophenol), and 60g of organic solvent (γ-butyrolactone).

[0044] Preparation method: According to the formulation, fluorine-free polyimide resin precursor A1, diazonaphthoquinone photosensitizer, thermal crosslinking agent (3,5-dimethoxyphenol), and cosolvent were added to γ-butyrolactone and stirred until completely dissolved. The mixture was then filtered through a 0.22 μm polytetrafluoroethylene filter membrane to obtain a fluorine-free positive photosensitive polyimide resin composition. The preparation methods for the following implementation examples and comparative examples are the same.

[0045] The preparation methods for the following implementation cases and comparative cases are the same.

[0046] Example 2, Composition formulation: 10g of fluorine-free polyimide resin precursor A1, 2.5g of 2,1,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (4,4'-dimethoxybiphenyl), 0.9g of cosolvent (2,4,6-tribromophenol), and 65g of organic solvent (500 parts of propylene glycol monomethyl ether + 1000 parts of γ-butyrolactone).

[0047] Example 3, composition formulation: 10g of fluorine-free polyimide resin precursor A2, 2.1g of 2,3,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (3,5-dimethoxyphenol), 0.9g of cosolvent (2,6-dichlorophenol), and 60g of organic solvent (γ-butyrolactone).

[0048] Example 4, Composition formulation: 10g of fluorine-free polyimide resin precursor A2, 2.5g of 2,1,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (4,4'-dimethoxybiphenyl), 0.9g of cosolvent (2,4,6-tribromophenol), and 65g of organic solvent (500 parts of propylene glycol monomethyl ether + 1000 parts of γ-butyrolactone).

[0049] Example 5, Composition formulation: 10g of fluorine-free polyimide resin precursor A3, 2.1g of 2,3,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (3,5-dimethoxyphenol), 0.9g of cosolvent (2,6-dichlorophenol), and 60g of organic solvent (γ-butyrolactone).

[0050] Example 6, Composition formulation: 10g of fluorine-free polyimide resin precursor A3, 2.5g of 2,1,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (4,4'-dimethoxybiphenyl), 0.9g of cosolvent (2,4,6-tribromophenol), and 65g of organic solvent (500 parts of propylene glycol monomethyl ether + 1000 parts of γ-butyrolactone).

[0051] Comparative Case 1, the composition formulation is as follows: 10g of fluorine-free polyimide resin precursor B1, 2.1g of 2,3,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (3,5-dimethoxyphenol), 0.9g of cosolvent (2,6-dichlorophenol), and 60g of organic solvent (γ-butyrolactone).

[0052] Comparative Case 2, the composition formulation is as follows: 10g of fluorine-free polyimide resin precursor B2, 2.5g of 2,1,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (4,4'-dimethoxybiphenyl), 0.9g of cosolvent (2,4,6-tribromophenol), and 65g of organic solvent (500 parts of propylene glycol monomethyl ether + 1000 parts of γ-butyrolactone).

[0053] Comparative Case 3, the composition formulation is as follows: 10g of fluorine-free polyimide resin precursor B3, 2.5g of 2,1,4-diazonaphthoquinone-5-sulfonate, 1.6g of thermal crosslinking agent (4,4'-dimethoxybiphenyl), 0.9g of cosolvent (2,4,6-tribromophenol), and 65g of organic solvent (500 parts of propylene glycol monomethyl ether + 1000 parts of γ-butyrolactone).

[0054] ,

[0055] , Analysis of the test results in the table above shows that the fluorine-free photosensitive polyimide precursor and composition prepared by this invention have advantages such as high sensitivity, high resolution, and high contrast. Simultaneously, the cured film exhibits high optical transmittance and low chromaticity, while also demonstrating excellent dielectric properties, thermal properties, and high adhesion to the substrate. It can meet the application requirements of microelectronic packaging insulating layers, pixel definition layers of flexible display substrates, planarization layers, and semiconductor passivation layers.

[0056] It should be understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A photosensitive polyimide precursor, characterized in that: It is polymerized from a core diamine monomer, an auxiliary diamine monomer and a tetracarboxylic dianhydride monomer. The core diamine monomer is a hydroxyl-containing spiro / fluorene ring diamine compound. The ratio of core diamine monomer to (core diamine monomer + auxiliary diamine monomer) is 0.1~1; and the ratio of (core diamine monomer + auxiliary diamine monomer) to tetracarboxylic dianhydride monomer is (0.7~1.1):

1.

2. The photosensitive polyimide precursor according to claim 1, characterized in that: Its molecular weight is 2000~100000.

3. The photosensitive polyimide precursor according to claim 1, characterized in that: The core diamine monomer is ， One or more of them.

4. The photosensitive polyimide precursor according to claim 1, characterized in that: The auxiliary diamine monomer is selected from one or more combinations of p-phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl sulfone, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl], 2,2-bis[3-(3-aminobenzoylamino)-4-hydroxyphenyl]propane, 1,4-bis(aminophenoxy)benzene, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, α,ω-bis(3-aminopropyl)polydimethylsiloxane, and bis(4-aminophenyl)tetramethyldisiloxane.

5. The photosensitive polyimide precursor according to claim 1, characterized in that: The tetracarboxylic dianhydride monomer is selected from one or more of the following aromatic / alicyclic tetracarboxylic dianhydrides: pyromellitic dianhydride, biphenyl dianhydride, diphenyl ether dianhydride, bisphenol A type diether dianhydride, benzophenone dianhydride, 4,4'-(4,4'-isopropyldiphenoxy) bisphthalic anhydride, hydrogenated pyromellitic dianhydride, bicyclo[2.2.2]octyl-7-ene-2,3,5,6-tetracarboxylic dianhydride, hydrogenated biphenyl dianhydride, norbornene-2,3,5,6-tetracarboxylic dianhydride.

6. The polymerization process for a photosensitive polyimide precursor as described in claim 1, characterized in that... Includes the following steps: S1 Preparation of polyamic acid solution: Diamine monomer is added to a polar organic solvent to form a monomer solution; Then, tetracarboxylic acid dianhydride monomer is slowly added to the monomer solution, and the reaction is carried out at a constant temperature to obtain a polyamic acid solution. S2 Preparation of polyimide resin precursor: Add end-capping agent to polyamic acid solution and react, then add esterification reagent and react.

7. The polymerization process for a photosensitive polyimide precursor according to claim 6, characterized in that: In step S1, the reaction temperature is ~20~60℃, the reaction time is 4~8h, and the solid content is controlled at 10~35wt%; in step S2, the end-capping agent reaction time is 1~4h, and the esterification reagent reaction time is 30~120min.

8. A polyimide composition prepared using the photosensitive polyimide precursor of claim 1, comprising: 5-40 parts of photosensitive polyimide precursor, 1-5 parts of photosensitizer, 1-5 parts of crosslinking agent, 0.2-2 parts of sensitizer, and 50-90 parts of organic solvent.

9. A polyimide composition according to claim 8, characterized in that: The photosensitizer is selected from one or more photoacid-producing agents such as diazonium quinone compounds, oxime sulfonate compounds, sulfonium salts, phosphonium salts, diazonium salts, and iodonium salts; the crosslinking agent is selected from one or more combinations of 4-methoxy-2,6-dimethylphenol, 3,4,5-trimethoxyphenol, 4,4'-dimethoxybiphenyl, 3,4,5-trimethoxyphenol, 1,1,1-tris[(2,6-dimethoxymethyl-4-hydroxy)phenyl]ethane, 4-ethyl-2-methoxyphenol, 2-methoxy-6-methylphenol, 3,3',5,5'-tetramethoxy-4,4'-dihydroxybiphenyl, and 4-methoxytriphenylmethyl alcohol; the sensitizer is 0.2-2 parts, selected from 4- One or more of the following: chlorophenol, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl)methane, 2,6-dichlorophenol, 1,1,1-tris(4-hydroxyphenyl)ethane, 2-bromophenol, and 2,4,6-tribromophenol.

10. A polyimide film, characterized in that: It is prepared using the polyimide composition according to claim 9.

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