Polyamide acid ester, photosensitive polyimide resin, negative photoresist composition and application thereof

Abstract

The invention provides polyamide acid ester, photosensitive polyimide resin, a negative photoresist composition and application thereof. A covalent bond on a side chain of the polyamic acid ester contains a benzoylmethyl-containing structure, the structure has an ultraviolet light sensing function and can realize light degradation, so that the polyamic acid ester is converted into polyamic acid and primary alcohol, and the formed polyamic acid can be dissolved in a water-based developing agent, so that the targets of water-based developing and photoetching are realized. Besides, after the polyamic acid ester provided by the invention is imidized, no crosslinking component is left, and the polyamic acid ester has high mechanical property, high resolution, high film thickness and depth-to-width ratio gt; and 2.0, good performance can be achieved even if low-temperature curing is carried out.

Description

Technical Field

[0001] This invention belongs to the field of photosensitive polyimide materials, specifically relating to a polyamide ester, a photosensitive polyimide resin, a negative photoresist composition, and their applications. Background Technology

[0002] Photosensitive polyimide (PSPI) is a class of polymeric materials containing photosensitive groups, sensitive to specific light, and capable of photochemical reactions under ultraviolet exposure. PSPI possesses the excellent heat resistance, mechanical properties, dielectric properties, and chemical resistance of traditional polyimide (PI) materials, and is widely used in semiconductor devices, integrated circuits, microelectromechanical systems (MEMS), and novel displays, demonstrating its increasing importance as a practical dielectric insulating or structural material. Research reports indicate that photosensitive polyimides, which impart photosensitivity to polyimides, and photoresist compositions containing photosensitive polyimides and photosensitizers, can achieve polyimide patterning through coating, exposure, development, and curing-based thermal curing (imidization).

[0003] In recent years, with the increasing portability and performance of various electronic devices such as smartphones, laptops, and AR devices, the requirements for miniaturization, thinning, and high density of semiconductor devices have increased. Especially from the perspective of improving integration and computing power, the packaging structure of integrated circuits is changing. Currently, high-density advanced packaging technologies such as wafer-scale packaging and three-dimensional stacking are developing rapidly. In these advanced packaging technologies, photosensitive polyimide, which can form patterns on a substrate, is used as a protective film, insulating layer, and dielectric layer. Its insulation, mechanical strength, heat resistance, and substrate adhesion continue to receive attention. In the aforementioned application scenarios, photosensitive polyimide is used to cover semiconductor chips, forming an insulating dielectric layer larger than the semiconductor chip. After photolithographic patterning, a rewiring layer can be constructed by depositing metal, thus facilitating the formation of multi-layer stacked chip packages.

[0004] To achieve planarization and precise interconnection of multilayer chip surfaces, the PSPI layer, serving as an interlayer planarization and insulating dielectric layer, typically needs a thickness greater than 20 micrometers, while maintaining an aperture size of less than 10 micrometers and an aspect ratio greater than 2.0. Furthermore, when the rewiring layer consists of two or more stacked layers, interlayer stress and in-plane inhomogeneities can easily form, causing problems such as cracks and warping. This necessitates that polyimide possess high mechanical properties, particularly flexibility.

[0005] Currently, photosensitive polyimide materials typically utilize polyimide precursors, namely polyamic acid derivatives, for example, by introducing photosensitive groups through ester bonds via the carboxyl groups of polyamic acid. However, after patterning, imidization treatment at temperatures exceeding 300°C is required to obtain the target polyimide. But high temperatures can affect the substrate or cause copper oxidation in the rewiring.

[0006] To address these issues, researchers have developed a photosensitive polyimide containing acrylate side chains. Its photolithography mechanism relies on the photocrosslinking of the acrylate side chains to construct a thermosetting network structure, reducing the dissolution rate and enabling photolithographic patterning. However, after the polyimide cures, the crosslinked acrylate often remains within the insulating dielectric layer, especially at lower curing temperatures. This residual, heat-sensitive crosslinking component easily degrades the mechanical properties and heat resistance of the polyimide, reducing its reliability. Furthermore, photosensitive polyimides based on the photocrosslinking of acrylate side chains require organic solvent development, which is not an ideal environmentally friendly development method. Summary of the Invention

[0007] In view of this, the object of the present invention is to provide a polyamic acid ester, a photosensitive polyimide resin, a negative photoresist composition and its application.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a polyamic acid ester having the structure shown in Formula I:

[0010] Formula I;

[0011] X is selected from substituted or unsubstituted C4~C20 cycloalkyl or substituted or unsubstituted C6~C30 aryl;

[0012] Y is selected from substituted or unsubstituted C6~C30 aryl groups or substituted or unsubstituted C2~C10 alkyl groups;

[0013] The structural formula of R1 is: ;

[0014] Among them, R h Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl groups, and substituted or unsubstituted C6-C30 aryl groups;

[0015] R n Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, halogen, hydroxyl, methoxy, amino, trifluoromethyl or nitro;

[0016] M is obtained by reacting an amino-containing capping agent or by reacting an anhydride-containing capping agent, wherein both the amino-containing capping agent and the anhydride-containing capping agent include R1.

[0017] n is an integer from 2 to 150.

[0018] Preferably, X is selected from any one of the following formulas X-1 to X-28:

[0019] .

[0020] Preferably, Y is selected from any one of the following formulas Y-1 to Y-24:

[0021]

[0022] ;

[0023] Rm is selected from alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, alkyl carbonyl or alkyloxycarbonyl.

[0024] Preferably, R1 is selected from any one of the following formulas A-1 to A-15:

[0025] .

[0026] Preferably, the end-capping agent is selected from any one of the following formulas B-1 to B-3:

[0027] .

[0028] In a second aspect, the present invention provides a photosensitive polyimide resin, which is obtained by imidizing the above-mentioned polyamic acid ester.

[0029] Thirdly, the present invention provides a negative photoresist composition, comprising, by weight:

[0030] 100 parts of the above-mentioned polyamic acid ester;

[0031] Photosensitizing agent 0.1~20 parts;

[0032] Solvent: 150-400 parts;

[0033] Imidization accelerator 1-300 parts.

[0034] Preferably, the photosensitizing agent is selected from any one or more of aromatic ketone compounds, benzoin compounds, or oxime ester compounds.

[0035] Preferably, the solvent is selected from any one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, tetrahydrofuran, diethylene glycol dimethyl ether, cyclohexanone, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl lactate, butyl lactate, dichloromethane, 1,2-dichloroethane, 1,3-dimethyl-2-imidazolium ketone, N-cyclohexyl-2-pyrrolidone, or 3-methoxy-N,N-dimethylpropionamide.

[0036] Preferably, the imidization accelerator is selected from organic bases and / or organic acids; the organic base is selected from any one or more of pyridine, substituted pyridine, quinoline, isoquinoline, trialkylamine, dimethylaminopyridine, imidazole, methylimidazolium, 1,8-diazabicyclo[5.4.0]undec-7-ene or 1,5-diazabicycloheptane; the organic acid is selected from any one or more of benzoic acid, hydroxybenzoic acid, hydroxypropionic acid, benzenesulfonic acid or hydroxybenzenesulfonic acid.

[0037] Preferably, the photoresist composition further includes any one or more of a coupling agent, a leveling agent, or a stabilizer.

[0038] Fourthly, the present invention provides an application of the above-described polyamic acid ester or the above-described photoresist composition as an insulating layer, passivation layer, interlayer dielectric layer, or pixel dividing layer in the semiconductor or display industry. For example, a display device including an insulating layer includes a first electrode formed on a substrate and a second electrode opposite to the first electrode. Specific examples of display devices include LCDs, ECDs, ELDs, and organic electroluminescent elements (also referred to as organic electroluminescent devices).

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] The polyamic acid ester provided by this invention has a covalently bonded side chain containing a benzoyl methyl group. This structure has ultraviolet photosensitive properties, enabling photodegradation and conversion of the polyamic acid ester into polyamic acid and a primary alcohol. The resulting polyamic acid is soluble in aqueous developers, thus achieving the goals of aqueous development and photolithography. Furthermore, the polyamic acid ester provided by this invention, after imidization, has no residual crosslinking components, exhibits high mechanical properties, high resolution, high film thickness, and an aspect ratio >2.0, and maintains excellent performance even under low-temperature curing. Attached Figure Description

[0041] Figure 1 SEM image of the film after thermosetting the composition obtained in Example 1;

[0042] Figure 2 The infrared spectrum of the polyamic acid ester in Example 1;

[0043] Figure 3 SEM image of the film after thermosetting the composition obtained in Example 2. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] Currently, in advanced packaging technologies such as 2.5D, 3D packaging, and system-in-package (SICP), photoresists used as interlayer media often require a thickness exceeding 20 micrometers, a lithographic resolution of <10 micrometers, an aspect ratio >2.0, and low-temperature curing. However, existing technologies struggle to simultaneously achieve high mechanical properties, high resolution, and high film thickness in photoresists, especially under low-temperature curing conditions.

[0046] Based on this, the present invention provides a photosensitive polyimide precursor based on the photodegradation of the side chain of the polyimide precursor, namely polyamic acid ester, which can have high mechanical properties, high resolution, high film thickness and aspect ratio >2.0 after imidization. It also has good performance even when cured at low temperature and can be developed in aqueous systems.

[0047] Specifically, the present invention provides a polyamic acid ester having the structure shown in Formula I:

[0048] Formula I;

[0049] Wherein, n is taken as an integer from 2 to 150. From the perspective of the photosensitivity and mechanical properties of the negative photosensitive resin composition, its degree of polymerization value n is preferably an integer from 5 to 100, and the weight-average molecular weight is (0.5~10)×10. 4 From the perspective of good dispersibility in aqueous developer and good pattern resolution performance, the weight-average molecular weight is preferably (1~5)×10. 4 .

[0050] In this invention, X in the structure shown in Formula I is a tetravalent organic group, which is the residue X of the monomer tetracarboxylic acid dianhydride of polyamic acid ester polymerization, and can be selected from a substituted or unsubstituted C4~C20 cycloalkyl group or a substituted or unsubstituted C6~C30 aryl group; Y is a divalent organic group, which is the residue Y of the monomer diamine of polyamic acid ester polymerization, and can be selected from a substituted or unsubstituted C6~C30 aryl group or a substituted or unsubstituted C2~C10 alkyl group.

[0051] In some embodiments of the present invention, X is selected from any one of the following formulas X-1 to X-28:

[0052] .

[0053] In some specific embodiments of the present invention, Y is selected from any one of the following formulas Y-1 to Y-24:

[0054]

[0055] .

[0056] The Rm mentioned above is selected from alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, alkyl carbonyl or alkyloxycarbonyl.

[0057] In this invention, R1 is a side group containing a benzoylmethyl structure, with the structural formula as follows: ;

[0058] Among them, R h Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl groups, and substituted or unsubstituted C6-C30 aryl groups;

[0059] R n Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, halogen (such as F, Cl, Br, I, etc.), hydroxyl, methoxy, amino, trifluoromethyl or nitro.

[0060] In this invention, R h and R n There can be multiple identical or different substituents.

[0061] In this invention, the side group R1 containing the benzoylmethyl structure is a UV-sensitive structure that enables the polyacrylate shown in Formula I to have photosensitive characteristics. It can be photodegraded to form polyamic acid and primary alcohol. The polyamic acid formed can be dissolved in an aqueous developer, achieving the goal of aqueous development and photolithography.

[0062] In some specific embodiments of the present invention, R1 is selected from any one of the following formulas A-1 to A-15:

[0063] .

[0064] The substituted groups in all of the "substituted or unsubstituted" mentioned above can be selected from C1 to C6 alkyl groups, C6 to C30 aryl groups, halogens (such as F, Cl, Br, I, etc.), hydroxyl groups, methoxy groups, amino groups, trifluoromethyl groups, or nitro groups.

[0065] In this invention, M in the structure shown in Formula I above is obtained by reacting with an end-capping agent, wherein the end-capping agent includes R1.

[0066] In some embodiments of the present invention, the capping agent is an amino-containing capping agent (Formula B-1 or Formula B-2) or an anhydride-containing capping agent (Formula B-3), with the following specific structural formula:

[0067] .

[0068] In this invention, the above-mentioned polyamic acid ester is difficult to dissolve in an alkaline aqueous solution used as a developer, and this is not changed by selecting or preferably using dianhydrides, diamines, and end group structures in the polyamic acid ester resin.

[0069] After UV exposure, the benzoyl methyl structure undergoes photodegradation, and the polyacrylate forms polyamic acid and primary alcohol. The polyamic acid formed is easily soluble in alkaline aqueous developer, creating a sufficient dissolution rate difference between the exposed and unexposed areas, thereby forming a negative lithography pattern and achieving the goal of aqueous development and lithography.

[0070] The material is readily soluble in alkaline aqueous developers, with a dissolution rate >0.1 μm / s in a 2.38% tetramethylammonium hydroxide aqueous solution. A preferred dissolution rate is 0.15~1.0 μm / s, which is considered essential for high photolithographic resolution. This high photolithographic resolution allows for the formation of patterned morphologies <20 μm, preferably <10 μm.

[0071] This invention also provides a method for preparing the above-mentioned polyamic acid ester, and the synthetic route is divided into the following two:

[0072] When the capping agent is an amino-containing capping agent, the synthetic route is as follows (where -NH-M1 is the residue remaining after the amino-containing capping agent has reacted):

[0073] ;

[0074] When the capping agent is an anhydride-containing capping agent, the synthetic route is as follows (where -M2 is the residue remaining after the reaction of the anhydride-containing capping agent):

[0075] .

[0076] The method for preparing the polyacrylate provided by this invention employs a conventional two-step process: first, a diester is synthesized, followed by a polycondensation reaction with a diamine and a capping agent. Crucially, the reaction temperature must be controlled below 20°C during the reaction. o C, to prevent the formation of byproducts that reduce product yield, such as cross-linking byproducts.

[0077] Specifically, the preparation method of the polyacrylate includes the following steps:

[0078] 1) Esterification reaction: The monomer tetracarboxylic acid dianhydride, the primary alcohol R1-OH containing R1, the catalyst, and the solvent are added to the reaction vessel. The temperature is controlled at 20~50℃, and the mixture is stirred for 4~10 h to dissolve and mix, thereby carrying out the esterification reaction of the anhydride group of the dianhydride to obtain the corresponding diacid diester;

[0079] 2) Activation reaction: While controlling the temperature <20°C o Under the cooling conditions of C, an activator is added to the above-mentioned diacid diester solution, and the activation reaction is carried out for 0.5~4 h;

[0080] 3) Polycondensation reaction: Continue adding monomeric diamine and capping agent to the reaction system, controlling the temperature to <20°C. o C, carry out polycondensation reaction for 4~24 h;

[0081] 4) Finally, add a poor solvent to the reaction system to precipitate the polyamic acid ester product in the reaction system, filter to separate the crude product, and vacuum dry to obtain the polyamic acid ester product.

[0082] 5) Analyze and test the molecular weight, viscosity, and dissolution rate of the obtained polyamic acid ester product in a 2.38% tetramethylammonium hydroxide aqueous solution.

[0083] In this invention, the structure of the aforementioned monomeric tetracarboxylic dianhydride is not particularly limited. Specifically, from the perspective of balancing heat resistance and photosensitivity, and from the perspective of facilitating the formation of high film thickness, high mechanical properties, chemical resistance, high resolution, and the reliability of packaged devices, the monomeric tetracarboxylic dianhydride can be selected from any one or more of the following: pyromellitic anhydride, diphenyl ether-3,3'4,4'-tetracarboxylic dianhydride, benzophenone-3,3'4,4'-tetracarboxylic dianhydride, biphenyl-3,3'4,4'-tetracarboxylic dianhydride, diphenyl sulfone-3,3'4,4'-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, diphenylmethane-3',3''4',4''-tetracarboxylic dianhydride, 1,4-diphenoxybenzene-3,3'4,4'-tetracarboxylic dianhydride, or 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane.

[0084] Similarly, the diamines containing the Y-structure are not particularly structurally limited. Specifically, considering both heat resistance and photosensitivity, as well as the glass transition temperature (Tg), mechanical properties, resolution, and in-plane uniformity when formed as a multilayer of the cured polyimide film, the diamines containing the Y-structure are particularly preferably p-phenylenediamine, 4,4-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4 '-Diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis(4-4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)ether, bis(4-(3-aminophenoxy)phenyl)ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenoxy)benzene Any one or more of the following: phenylbenzene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, or 9,9-bis(4-aminophenyl)fluorene, and substances obtained by substituting a portion of the hydrogen atoms on their benzene rings with methyl, ethyl, trifluoromethyl, methoxy, hydroxymethyl, hydroxyethyl, halogen, etc., for example... The mixture comprises, but is not limited to, any one or more of 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-ditrifluoromethyl-4,4'-diaminodiphenylmethane, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,4'-diaminobiphenyl, or 3,3'-dichloro-4,4'-diaminobiphenyl.

[0085] In this invention, the reaction conversion rate of the diacid diester intermediate formed by the above esterification reaction needs to be >98%. The conversion rate can be determined by known methods, for example, the reaction conversion rate can be determined by NMR to ensure that the product yield is high enough.

[0086] The solvent is a commonly used solvent for polyimide polymerization, and can be selected from any one or more of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, γ-butyrolactone, ketones, esters, lactones, ethers, halogenated hydrocarbons, hydrocarbons, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, chlorobenzene, o-dichlorobenzene, hexane, heptane, benzene, toluene, or xylene.

[0087] The catalyst is a tertiary amine catalyst, preferably pyridine, substituted pyridine, quinoline, isoquinoline, triethylamine, dimethylaminopyridine, or imidazole. The molar amount of the catalyst added is 20-300% of the molar amount of tetracarboxylic dianhydride, preferably 100-200%, and includes any one or more of these.

[0088] In this invention, the activation reaction is used to activate the carboxyl group in the diacid diester, which can then undergo polycondensation with a diamine. Preferably, the carboxyl group activation is performed first. The use of the activator varies depending on whether an amide condensing agent is used or an activation method is employed to form an acyl halide from the diacid. When using an amide condensing agent, the activator includes dicyclohexylcarbodiimide, diisopropylcarbodiimide, carbonyldiimidazole, 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, 1,1-carbonyldioxy-di-1,2,3-benzotriazole, N,N'-disuccinimidyl carbonate, preferably any one or more of dicyclohexylcarbodiimide, diisopropylcarbodiimide, or carbonyldiimidazole. For the activation method to form an acyl halide, the activator preferably uses thionyl chloride and / or phosphorus oxychloride.

[0089] In this invention, after the condensation reaction of the amide is completed, the byproducts of the dehydrating condensing agent coexisting in the reaction solution are filtered and separated as needed. Then, undesirable solvents such as water, aliphatic lower alcohols, or mixtures thereof are added to the obtained polymer components to precipitate the polymer, thus separating the target polyimide precursor. Alternatively, this invention can repeat operations such as re-dissolution and re-precipitation to purify the polymer, followed by vacuum drying. To improve the purification degree, the solution containing the polymer can be poured into a suitable organic solvent, stirred in the organic solvent, and passed through an anion exchange resin or cation exchange resin, or through an ion exchange column formed by the swelling phenomenon between the polymer and the organic solvent, to remove ionic impurities.

[0090] In this invention, the proportions of the reactants are as follows: as the selection of the highest molecular weight to form the condensation polymer, the molar ratio of (dianhydride:diamine) is preferably as close to 1:1 as possible.

[0091] Specifically, if the capping agent is an amine-containing capping agent, the molar ratio of the polymerized substances used is dianhydride:R1-OH:diamine:capping agent = 100:(200~250):(90~110):(20~4), preferably 100:(200~210):(94~98):(8~4); if the capping agent is an anhydride-containing capping agent, the molar ratio of the polymerized substances used is dianhydride:R1-OH:diamine:capping agent = (90~110):(200~250):100:(20~4), preferably (94~98):(200~210):100:(8~4).

[0092] The present invention also provides a photosensitive polyimide resin, which is obtained by high-temperature imidization of the above-mentioned polyamic acid ester after photolithography to form a pattern.

[0093] This invention also provides a photoresist system with a negative photolithographic pattern, comprising a composition slurry of the polyacrylate resin of this invention, the components of which include at least a photosensitizing agent, a solvent, and an imidization accelerator. If necessary, auxiliary components to improve the effect may also be added. These auxiliary components may include coupling agents, leveling agents, stabilizers, etc.

[0094] As a feature of this invention, the photoresist system of this invention does not necessarily contain a dissolution rate control agent. Typically, such dissolution rate control agents refer to DNQ-type compounds, i.e., diazonoquinone sulfonates. In a typical negative photoresist system, DNQ, as a photosensitive substance, is mixed into the resin and, after illumination, forms indole acid, which assists the polyimide precursor in dissolving in an alkaline aqueous solution, thereby achieving aqueous development and negative photolithographic patterning.

[0095] In this invention, the photoactive structure is a side group containing a benzoyl methyl structure covalently bonded to the main chain structure of the polyimide molecule. This side group is a UV-sensitive structure that can achieve photodegradation, converting the polyamide precursor polyacrylate into polyamic acid and primary alcohol. The resulting polyamic acid can be dissolved in an aqueous developer, achieving the goal of aqueous development and photolithography. Therefore, it is a negative photoresist system that does not require the addition of external photosensitive additives.

[0096] As a component ratio of the photoresist system, specifically, by weight, it includes:

[0097] 100 parts of the above-mentioned polyamic acid ester;

[0098] Photosensitizing agent 0.1~20 parts;

[0099] Solvent: 150-400 parts;

[0100] Imidization accelerator 1-300 parts.

[0101] In this invention, the photosensitizer is a substance that, upon absorbing light of a specific wavelength, can generate reactive intermediates (such as free radicals or cations) that initiate degradation reactions, or that enhances photoreaction efficiency or broadens the photosensitive wavelength range by absorbing and transferring light energy. The photosensitizer can be a common type of photosensitizer with good absorption at ultraviolet wavelengths of 365 nm and 405 nm, such as aromatic ketone compounds, benzoin compounds, and oxime ester compounds. Specifically, the photosensitizer can be selected from benzophenone, N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (milchone), 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-isopropylthioxanthone, diethylthioxanthone, 4-benzoyl-4'-methyldiphenyl sulfide, benzoyladium dimethyl ketal, benzoin, methylbenzoin, benzoin methyl ether, benzoin phenyl ether; 1-[4-(phenylthio)-2-(O-benzoyl oxime)], 1-[9 [Ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), 1-phenyl-1,2-butanedione-2-(o-methoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl) oxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl) oxime, or 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. In the photosensitive resin composition of this embodiment, photosensitizing agents can be arbitrarily added to improve photosensitivity. Especially from the viewpoint of resolution, aromatic ketone compounds and / or oxime ester compounds are more preferred.

[0102] In this invention, the amount of photosensitizing agent mixed with 100 parts of polyamic acid ester is preferably 0.1 to 20 parts. From the perspective of photosensitivity or pattern forming properties, the amount of photosensitizing agent mixed with 1.0 to 10 parts is preferably 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts, etc.

[0103] In this invention, the solvent can be any solvent that can uniformly dissolve or suspend the above-mentioned polyimide precursor (i.e., polyamic acid ester) and photosensitizer. Generally, it is 150 to 400 parts relative to 100 parts of polyamic acid ester, such as 150 parts, 200 parts, 250 parts, 300 parts, 350 parts or 400 parts, etc. Specifically, the solvent may be selected from any one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, tetrahydrofuran, diethylene glycol dimethyl ether, cyclohexanone, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl lactate, butyl lactate, dichloromethane, 1,2-dichloroethane, 1,3-dimethyl-2-imidazolium ketone, N-cyclohexyl-2-pyrrolidone, or 3-methoxy-N,N-dimethylpropionamide.

[0104] In this invention, the imidization accelerator is a compound that can reduce the conversion of polyimide precursors (polyamic acid esters) to polyimide through imidization. For example, applications in integrated circuit packaging, OLED pixel definition layers, etc., require low imidization temperatures, necessitating the addition of an imidization accelerator. These imidization accelerators can be organic bases or organic acids. The organic base can be selected from any one or more of pyridine, substituted pyridine, quinoline, isoquinoline, trialkylamine, dimethylaminopyridine, imidazole, methylimidazole, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), or 1,5-diazabicycloheptane (DBN). The organic acid can be selected from any one or more of benzoic acid, hydroxybenzoic acid, hydroxypropionic acid, benzenesulfonic acid, or hydroxybenzenesulfonic acid.

[0105] Adding the aforementioned imidization accelerator can reduce the imidization (curing) temperature from >300°C. o C decreased to <250 o C. It can also lower the imidization (curing) temperature to <200°C. o C, for example, using organic bases such as dimethylaminopyridine, methylimidazolium, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicycloheptane (DBN).

[0106] From the perspective of lowering the imidization temperature, the amount of imidization accelerator used is 1 to 100 parts relative to 100 parts of polyimide precursor (polyamide ester), preferably 1 to 20 parts.

[0107] From the perspective of high film thickness and high resolution of the formed PSPI pattern, it can be used as an imidization promoter of organic base, or as an ammonium salt formed by organic base and carboxylic acid after light irradiation, to increase the dissolution rate and further increase the dissolution rate difference, thereby facilitating the achievement of high film thickness and high resolution pattern. At this time, the amount of organic base used is 1 to 300 parts relative to 100 parts of polyimide precursor (polyamic acid ester), preferably 1 to 200 parts.

[0108] The present invention also provides a use of the above-mentioned photoresist system, which is generally a solution-based photoresist system that can form patterned morphologies through coating, pre-baking, exposure, development, and thermal curing processes.

[0109] The specific implementation process includes:

[0110] 1) Coating: Applying the photoresist solution onto the substrate. Conventional methods for coating photosensitive resins can be used, such as spin coating, rod coating, doctor blade coating, screen printing, and spray coating.

[0111] 2) Pre-drying: As a drying method, examples include air drying, heating drying based on an oven or heating plate, vacuum drying, etc., which can be carried out at 50~140℃ for 1 min~1 h.

[0112] 3) Exposure: Using exposure devices such as contact lithography machines, projection exposure machines, and stepper exposure machines, with or without the aid of patterned photomasks or gratings, the dried resin layer is exposed using ultraviolet light sources.

[0113] To improve light sensitivity, post-exposure baking (PEB) and / or pre-development baking can also be performed. Regarding the baking conditions, the preferred temperature is 40–120°C, and the preferred time is 10–240 s.

[0114] 4) Development: Due to exposure, the side groups in the polyaminate are photodegraded and can be dissolved in the developer, which can then be removed during the development process. Examples of development methods for developing the exposed resin layer include known photoresist development methods such as spin spraying and immersion methods with ultrasonic treatment.

[0115] As the developing solution used in development, the present invention preferably uses an alkaline aqueous solution to suit most current application scenarios and better environmental protection requirements. The alkaline aqueous developing solution can be an aqueous solution of sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, or tetraalkylammonium hydroxide, preferably a tetramethylammonium hydroxide aqueous solution.

[0116] 5) Thermal curing: The polyaminate described in this invention is imidized by heating, thereby converting it into polyimide, to form a cured pattern. Simultaneously, the photosensitive components in the system are degraded and volatilized by heating. Methods for thermal curing include heating plate-based methods, methods using an oven, and methods using a temperature-programmable oven, etc.

[0117] Finally, the present invention also provides an application of the above-mentioned polyamic acid ester or photoresist system in the semiconductor or display industry as an insulating layer, passivation layer, interlayer dielectric layer, or pixel dividing layer. For example, a display device including an insulating layer includes a first electrode formed on a substrate and a second electrode opposite to the first electrode. Specific examples of display devices include LCDs, ECDs, ELDs, and organic light-emitting elements (organic electroluminescent devices).

[0118] To further illustrate the present invention, the following embodiments provide a detailed description. The experimental materials used in the following embodiments of the present invention are all commercially available products.

[0119] Example 1

[0120] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol of 4,4-pyromellitic dianhydride (PMDA), 0.2 mol of 2-hydroxy-1-phenylethyl ketone, and 0.20 mol of pyridine were dissolved in 100 g of N,N-dimethylformamide (DMF) solvent with continuous stirring. The reaction temperature was lowered to within 20°C, and the reaction was allowed to proceed for 4 h until complete dissolution. 0.20 mol of dicyclohexylcarbodiimide (DCC) was added to the transparent solution, and the reaction temperature was maintained at 20°C for 2 h to activate the reaction. 0.094 mol of p-phenylenediamine (PPD) and 0.008 mol of 2-oxo-2-phenylethyl-4-aminobenzoate were then added, and the polycondensation reaction continued for 5 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin, the structure of which is shown below:

[0121] .

[0122] Take 2 g of photosensitive polyaminate resin, 0.02 g of benzophenone, 3.0 g of N-methyl-2-pyrrolidone (NMP), and 3.0 g of dimethylaminopyridine, stir and mix them evenly to obtain a negative polyaminate resin composition.

[0123] Example 2

[0124] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol of 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (BPDA), 0.202 mol of 1-(2,5-dimethylphenyl)-2-hydroxyethyl ketone, and 0.20 mol of quinoline were dissolved in 100 g of N,N-dimethylacetamide (DMAc) solvent with continuous stirring. The reaction temperature was lowered to 20 °C, and the reaction was allowed to proceed for 6 h until complete dissolution. 0.20 mol of DCC was added to the transparent solution, and the reaction temperature was maintained at 20 °C for 4 h to activate the reaction. 0.095 mol of 4,4'-diaminodiphenyl ether (ODA) and 0.008 mol of 2-(2-hydroxyphenyl)-2-oxoethyl 4-aminobenzoate were then added, and the polycondensation reaction continued for 10 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin, the structure of which is shown below:

[0125] .

[0126] Take 2 g of photosensitive polyaminate resin, 0.04 g of N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (Michidone), 4.0 g of DMF, and 3.2 g of methylimidazole, stir and mix evenly to obtain a negative polyaminate resin composition.

[0127] Example 3

[0128] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol of 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 0.205 mol of 2-hydroxy-1-(2-hydroxyphenyl)ethyl ketone, and 0.20 mol of triethylamine were dissolved in 100 g of γ-butyrolactone solvent with continuous stirring. The reaction temperature was lowered to 20°C, and the reaction was allowed to proceed for 8 hours until complete dissolution. 0.20 mol of DCC was added to the transparent solution, and the reaction temperature was maintained at 20°C for 3 hours to activate the reaction. 0.096 mol of 4,4'-diaminodiphenyl sulfone (DDS) and 0.008 mol of 2-(naphthyl-2-yl)-2-oxoethyl 4-aminobenzoate were then added, and the polycondensation reaction continued for 15 hours. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyamide ester resin, the structure of which is shown below:

[0129] .

[0130] Take 2 g of photosensitive polyaminate resin, 0.1 g of 4-methoxy-4'-dimethylaminobenzophenone, 5.0 g of DMAc, and 3.4 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), stir and mix evenly to obtain a negative polyaminate resin composition.

[0131] Example 4

[0132] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol of diphenyl ether-3,3',4,4'-tetracarboxylic acid dianhydride (ODPA), 0.208 mol of 2-hydroxy-1-(naphthyl-2-yl)ethyl ketone, and 0.20 mol of dimethylaminopyridine were dissolved in 100 g of dimethyl sulfoxide (DMSO) solvent with continuous stirring. The reaction temperature was lowered to 20°C, and the reaction was allowed to proceed for 10 h until complete dissolution. 0.20 mol of DCC was added to the transparent solution, and the reaction temperature was maintained at 20°C for 2 h to activate the reaction. 0.097 mol of PPD and 0.006 mol of 2-oxo-2-phenylethyl-4-aminobenzoate were then added, and the polycondensation reaction continued for 15 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyamide ester resin, the structure of which is shown below:

[0133] .

[0134] Take 2 g of photosensitive polyaminate resin, 0.16 g of diethylthioxanone, 6.0 g of cyclopentanone, and 3.6 g of 1,5-diazabicycloheptane (DBN), stir and mix them evenly to obtain a negative polyaminate resin composition.

[0135] Example 5

[0136] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol PMDA, 0.210 mol 2-hydroxy-1-phenylethyl ketone, and 0.20 mol imidazole were dissolved in 100 g DMAc solvent and stirred continuously. The reaction temperature was lowered to 20 °C, and the reaction was allowed to proceed for 12 h until complete dissolution. 0.20 mol DCC was added to the transparent solution, and the reaction temperature was maintained at 20 °C for 3 h to activate the reaction. 0.098 mol ODA and 0.004 mol 2-(2-hydroxyphenyl)-2-oxyethyl 4-aminobenzoate were then added, and the polycondensation reaction continued for 20 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyamide ester resin, with the following structural formula:

[0137] .

[0138] Take 2 g of photosensitive polyaminate resin, 0.2 g of 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], 8.0 g of DMF, and 4.0 g of dimethylaminopyridine, stir and mix evenly to obtain a negative polyaminate resin composition.

[0139] Example 6

[0140] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.094 mol BPDA, 0.20 mol 1-(2,5-dimethylphenyl)-2-hydroxyethyl ketone, and 0.188 mol pyridine were dissolved in 100 g NMP solvent with continuous stirring. The reaction temperature was lowered to 20°C, and the reaction was allowed to proceed for 14 h until complete dissolution. 0.188 mol DCC was added to the transparent solution, and the reaction temperature was maintained at 20°C for 4 h to activate the reaction. 0.10 mol DDS and 0.008 mol 2-oxo-2-phenylethyl 1,3-dioxy-1,3-hydroisobenzofuran-5-carboxylic acid ester were then added, and the polycondensation reaction continued for 24 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyamide ester resin, the structure of which is shown below:

[0141] .

[0142] Take 2 g of photosensitive polyaminate resin, 0.02 g of benzophenone, 3.0 g of γ-butyrolactone, and 3.0 g of dimethylaminopyridine, stir and mix them evenly to obtain a negative polyaminate resin composition.

[0143] Example 7

[0144] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.095 mol BTDA, 0.202 mol 2-hydroxy-1-(2-hydroxyphenyl)ethyl ketone, and 0.19 mol pyridine were dissolved in 100 g γ-butyrolactone solvent with continuous stirring. The reaction temperature was lowered to 20°C, and the reaction was allowed to proceed for 16 h until complete dissolution. 0.19 mol DCC was added to the transparent solution, and the reaction temperature was maintained at 20°C for 2 h to activate the reaction. 0.10 mol PPD and 0.008 mol 2-(2-hydroxyphenyl)-2-oxoethyl 1,3-dioxy-1,3-dihydroisobenzofuran-5-carboxylic acid ester were then added, and the polycondensation reaction continued for 24 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin, the structure of which is shown below:

[0145] .

[0146] Take 2 g of photosensitive polyaminate resin, 0.04 g of N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (michalcone), 4.0 g of DMSO, and 3.2 g of methylimidazole, stir and mix evenly to obtain a negative polyaminate resin composition.

[0147] Example 8

[0148] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.096 mol ODPA, 0.205 mol 2-hydroxy-1-(naphthyl-2-yl)ethyl ketone, and 0.192 mol pyridine were dissolved in 100 g DMF solvent with continuous stirring. The reaction temperature was lowered to 20°C, and the reaction was allowed to proceed for 16 h until complete dissolution. 0.192 mol DCC was added to the transparent solution, and the reaction temperature was maintained at 20°C for 3 h to activate the reaction. 0.10 mol ODA and 0.008 mol 2-oxo-2-phenylethyl 1,3-dioxy-1,3-hydroisobenzofuran-5-carboxylic acid ester were then added, and the polycondensation reaction continued for 4 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyamide ester resin, the structure of which is shown below:

[0149] .

[0150] Take 2 g of photosensitive polyaminate resin, 0.1 g of 4-methoxy-4'-dimethylaminobenzophenone, 5.0 g of DMAc, and 3.4 g of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), stir and mix evenly to obtain a negative polyaminate resin composition.

[0151] Example 9

[0152] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.097 mol PMDA, 0.208 mol 2-hydroxy-1-phenylethyl ketone, and 0.194 mol pyridine were dissolved in 100 g γ-butyrolactone solvent with continuous stirring. The reaction temperature was lowered to 20 °C, and the reaction was allowed to proceed for 18 h until complete dissolution. 0.194 mol DCC was added to the transparent solution, and the reaction temperature was maintained at 20 °C for 4 h to activate the reaction. 0.10 mol DDS and 0.006 mol 2-(2-hydroxyphenyl)-2-oxoethyl 1,3-dioxy-1,3-dihydroisobenzofuran-5-carboxylic acid ester were then added, and the polycondensation reaction continued for 6 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin, the structure of which is shown below:

[0153] .

[0154] Take 2 g of photosensitive polyaminate resin, 0.16 g of diethylthioxanone, 6.0 g of cyclopentanone, and 3.6 g of 1,5-diazabicycloheptane (DBN), stir and mix them evenly to obtain a negative polyaminate resin composition.

[0155] Example 10

[0156] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.098 mol BPDA, 0.210 mol 1-(2,5-dimethylphenyl)-2-hydroxyethyl ketone, and 0.196 mol pyridine were dissolved in 100 g NMP solvent with continuous stirring. The reaction temperature was lowered to 20°C, and the reaction was allowed to proceed for 18 h until complete dissolution. 0.196 mol DCC was added to the transparent solution, and the reaction temperature was maintained at 20°C for 2 h to activate the reaction. 0.10 mol PPD and 0.004 mol 2-oxo-2-phenylethyl 1,3-dioxy-1,3-hydroisobenzofuran-5-carboxylic acid ester were then added, and the polycondensation reaction continued for 10 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin, the structure of which is shown below:

[0157] .

[0158] Take 2 g of photosensitive polyaminate resin, 0.2 g of 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], 8.0 g of DMSO, and 4.0 g of dimethylaminopyridine, stir and mix evenly to obtain a negative polyaminate resin composition.

[0159] Comparative Example 1

[0160] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol PMDA, 0.20 mol hydroxyethyl methacrylate, and 0.20 mol pyridine were dissolved in 100 g DMF solvent and stirred continuously. The reaction temperature was lowered to 20°C and the reaction was allowed to proceed for 4 h until all the solvent was dissolved. 0.20 mol DCC was added to the transparent solution, and the reaction temperature was controlled at 20°C for 2 h to activate the reaction. 0.10 mol PPD was then added, and the polycondensation reaction was continued for 5 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin.

[0161] Take 2 g of photosensitive polyaminate resin, 0.04 g of benzophenone, 0.04 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 0.04 g of 2,6-di-tert-butyl-p-methylphenol, and 3.0 g of NMP, stir and mix evenly to obtain a negative polyaminate resin composition.

[0162] Comparative Example 2

[0163] Nitrogen gas was introduced into the reaction vessel at room temperature. 0.10 mol PMDA, 0.20 mol hydroxyethyl methacrylate, and 0.20 mol pyridine were dissolved in 100 g DMF solvent and stirred continuously. The reaction temperature was lowered to within 20°C, and the reaction was allowed to proceed for 4 h until all the solvent was dissolved. 0.26 mol DCC was added to the transparent solution, and the reaction temperature was controlled within 20°C for 2 h to activate the reaction. 0.094 mol PPD and 0.008 mol p-aminoanisole were then added, and the polycondensation reaction was continued for 5 h. After the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction. The reaction product was then poured into anhydrous ethanol to precipitate, and finally filtered and dried to obtain the photosensitive polyaminate resin.

[0164] Take 2 g of photosensitive polyaminate resin, 0.1 g of N-alkylaminoacetophenone, 0.06 g of N-phenyl-3-aminopropyltrimethoxysilane, 0.06 g of 4-methoxyphenol, and 4.0 g of DMF, stir and mix them evenly to obtain a negative polyaminate resin composition.

[0165] Performance testing

[0166] 1. Performance testing of photosensitive polyimide resin

[0167] The molecular weight and viscosity of the obtained polyamic acid ester resin products were analyzed and tested, as well as the dissolution rate of the polyamic acid ester resin in 2.38% tetramethylammonium hydroxide aqueous solution in the examples and the dissolution rate of the polyamic acid ester resin in cyclopentanone in the comparative examples.

[0168] Molecular weight: GPC data of polyamic acid esters were determined using a PL-GPC220 high-temperature gel permeation chromatography system from Agilent Technologies, USA.

[0169] Viscosity: Three measurements were taken using an Ubbelohde viscometer, and the average value was calculated.

[0170] Dissolution rate: Dissolve 2.0 g of polyamic acid ester resin in 10 ml of NMP solution, then spin coat the adhesive onto a silicon substrate, heat and dry the silicon wafer on a hot plate, dry at 100°C for 10 minutes, test the thickness of the adhesive film, immerse the silicon substrate coated with the adhesive film in a 2.38% tetramethylammonium hydroxide aqueous solution, record the time required for the film to completely dissolve, and divide the film thickness by the time to obtain the dissolution rate.

[0171] 2. Performance testing of the photosensitive polyimide composition

[0172] Polyimide photoresist solutions can be patterned into morphologies through processes such as coating, pre-baking, exposure, development, and thermal curing.

[0173] 1) Coating: Spin-coating the photoresist solution onto the silicon substrate.

[0174] 2) Pre-baking: Heat the silicon wafer on a heating plate and dry it at 100°C for 10 minutes.

[0175] 3) Exposure: A projection exposure machine is used with a patterned photomask and an ultraviolet light source to expose the dried resin layer. The baking (PEB) conditions after exposure are 70°C for 120 seconds.

[0176] 4) Development: In the examples, a 2.38% tetramethylammonium hydroxide (TMAH) aqueous solution was used as the developer, while in the comparative example, cyclopentanone was used as the developer. Development was performed using a rotary spray method.

[0177] 5) Thermal curing: The pattern is thermally imidized using an oven with a stepped heating method. The stepped heating method is to hold at 100°C for 1 hour and at 200°C for 1 hour, with a heating rate of 2~10°C / minute.

[0178] The film was then cooled to room temperature, and the pattern was peeled off from the substrate. The film thickness was measured using a film thickness gauge, and the resolution and aspect ratio of the film were observed on the bevel using an ESEM XL-30 field emission environmental scanning electron microscope.

[0179] Imidification rate: The infrared spectrum of a 10 µm PSPI film prepared after patterning was measured using a Fourier transform infrared spectrometer. A sample from 1380 cm⁻¹ was used.-1 CN stretching vibration and 1500cm -1 The ratio of the characteristic peaks of the benzene ring stretching vibration was calculated, and the imidization rate of each PSPI sample was calculated by taking the PSPI treated at 350℃ for 1h as the 100% imidized sample.

[0180] Mechanical properties: The tensile strength (σm), tensile modulus (Et), and elongation at break (εb) of the polyimide film were tested using an INSTRON-1121 universal testing machine from Instrand at a stretching rate of 5 mm / min.

[0181] The SEM image of the film obtained in Example 1 after thermosetting is shown below. Figure 1 As shown, the lithography resolution is 6 μm, and the lines are clearly visible in the SEM image.

[0182] The infrared spectrum of the polyaminate resin obtained in Example 1 is shown below. Figure 2 As shown in the figure, 1594 cm -1 Nearby amide bond, NH bending vibration peak, 1436 cm⁻¹ -1 The presence of nearby amide bonds, CN stretching vibration peaks, and the aforementioned vibrational absorption peaks confirms the formation of the -CONH- amide bond. At 1634 cm⁻¹ -1 The vibrational peaks that appeared were attributed to the C=O vibration in acetone, indicating that the polyamic acid ester was successfully prepared.

[0183] The SEM image of the film obtained in Example 2 after thermosetting is shown below. Figure 3 As shown, the pattern with a photolithographic resolution of 7 μm can be seen from the SEM image as having clear line edges.

[0184] The test results of the photosensitive polyimide resins in Examples 1-10 and Comparative Examples 1-2 are shown in Table 1:

[0185] Table 1

[0186]

[0187] The test results of the photosensitive polyimide compositions of Examples 1-10 and Comparative Examples 1-2 are shown in Tables 2 and 3:

[0188] Table 2

[0189]

[0190] Table 3

[0191]

[0192] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0193] By introducing a UV-sensitive structure containing benzoyl methyl groups into the side chains of polyimide polymers, polyamide esters can acquire photosensitive characteristics, enabling photodegradation and the formation of polyamic acid and primary alcohol. The resulting polyamic acid is soluble in aqueous developers, achieving the goals of aqueous development and photolithography. Furthermore, by introducing end-capping agents containing benzoyl methyl groups, the molecular weight can be controlled, increasing the dissolution rate of polyamide ester resin and polyamic acid films in alkaline developers, resulting in higher photolithographic resolution (≤10 μm). Additionally, by adding an imidization accelerator organic base to the photosensitive polyimide composition, the curing temperature of the film can be lowered to below 200°C due to catalytic action. o Complete imidization is achieved at C. The photosensitive polyimide obtained by this invention not only has excellent mechanical properties, but also a film thickness loss rate of <15% and an aspect ratio of >2.0.

[0194] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polyamic acid ester, characterized in that, It has the structure shown in Equation I: Formula I; X is selected from substituted or unsubstituted C4~C20 cycloalkyl or substituted or unsubstituted C6~C30 aryl; Y is selected from substituted or unsubstituted C6~C30 aryl groups or substituted or unsubstituted C2~C10 alkyl groups; The structural formula of R1 is: ; Among them, R h Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl groups, and substituted or unsubstituted C6-C30 aryl groups; R n Selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, halogen, hydroxyl, methoxy, amino, trifluoromethyl or nitro; M is obtained by reacting an amino-containing capping agent or by reacting an anhydride-containing capping agent, wherein both the amino-containing capping agent and the anhydride-containing capping agent include R1. n is an integer from 2 to 150.

2. The polyamic acid ester according to claim 1, characterized in that, X is selected from any one of the following formulas X-1 to X-28: 。 3. The polyamic acid ester according to claim 1 or 2, characterized in that, The Y is selected from any one of the following formulas Y-1 to Y-24: ； Rm is selected from alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, alkyl carbonyl or alkyloxycarbonyl.

4. The polyamic acid ester according to any one of claims 1 to 3, characterized in that, R1 is selected from any one of the following formulas A-1 to A-15: 。 5. The polyamic acid ester according to any one of claims 1 to 4, characterized in that, The capping agent is selected from any one of the following formulas B-1 to B-3: 。 6. A photosensitive polyimide resin, characterized in that, It is obtained by imidizing the polyaminate according to any one of claims 1 to 5.

7. A negative photoresist composition, characterized in that, By weight, it includes: 100 parts of the polyamic acid ester according to any one of claims 1 to 5; Photosensitizing agent 0.1~20 parts; Solvent: 150-400 parts; Imidization accelerator 1-300 parts.

8. The photoresist composition according to claim 7, characterized in that, The photosensitizing agent is selected from any one or more of aromatic ketone compounds, benzoin compounds, or oxime ester compounds; The solvent is selected from any one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, tetrahydrofuran, diethylene glycol dimethyl ether, cyclohexanone, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl lactate, butyl lactate, dichloromethane, 1,2-dichloroethane, 1,3-dimethyl-2-imidazolium ketone, N-cyclohexyl-2-pyrrolidone, or 3-methoxy-N,N-dimethylpropionamide. The imidization accelerator is selected from organic bases and / or organic acids; the organic base is selected from any one or more of pyridine, substituted pyridine, quinoline, isoquinoline, trialkylamine, dimethylaminopyridine, imidazole, methylimidazolium, 1,8-diazabicyclo[5.4.0]undec-7-ene or 1,5-diazabicycloheptane; the organic acid is selected from any one or more of benzoic acid, hydroxybenzoic acid, hydroxypropionic acid, benzenesulfonic acid or hydroxybenzenesulfonic acid.

9. The photoresist composition according to claim 7 or 8, characterized in that, The photoresist composition also includes any one or more of coupling agents, leveling agents, or stabilizers.

10. The polyamic acid ester of any one of claims 1 to 5 or the negative photoresist composition of any one of claims 7 to 9, used in the semiconductor or display industry as an insulating layer, passivation layer, interlayer dielectric layer, or pixel dividing layer.

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