Photosensitive resin composition, cured film and display device

Abstract

A photosensitive resin composition applied to the technical field of photoelectric display, a cured film and a display device. The photosensitive resin composition comprises an alkali-soluble resin, a photosensitizer and an organic solvent, wherein the transmittance of a slurry, which is obtained after the photosensitive resin composition is diluted 100 times, under a wavelength λ1 is R1, and the transmittance of the cured film under a wavelength λ2 is R2. The wavelengths λ1 and λ2 are within the range of 380-780 nm, and when λ1 is equal to λ2, the ratio of R1 to R2 is 0.0001-1.2. The cured film is a film having a thickness of 1.5 microns, which is obtained by curing a wet film at 250ºC for 1 h after coating. The photosensitive resin composition can inhibit TFT threshold voltage / current drift and avoid afterimages when being used for a flexible OLED apparatus and forming a planarization layer and an insulating layer material, and also has good photosensitive performance, a high residual film rate, a high resolution and good gas escape performance.

Description

Photosensitive resin composition, cured film and display device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to a Chinese patent application filed on June 29, 2023, with application number 202310777587.6, entitled “Photosensitive resin composition, cured film and display device”. The entire contents of the above Chinese patent application are hereby incorporated into this application by reference. Technical Field

[0003] The present invention relates to the field of optoelectronic display technology, in particular to a photosensitive resin composition, a cured film and a display device. Background Art

[0004] In recent years, active-matrix organic light-emitting diodes (AMOLEDs) have received widespread attention and application due to their advantages such as ultra-thinness, flexibility, wide viewing angle, wide color gamut, and low power consumption. They are regarded as a new generation of display technology (CN114107895A). Research and development on them is becoming increasingly popular. Among them, the problem of OLED display afterimages, especially in flexible OLED devices, is a key issue that urgently needs to be studied and resolved. OLED display afterimages refer to the phenomenon that as the operating time of the OLED display increases and the OLED ages, the brightness information of the previous image remains on the new image when the pixel image switches. This phenomenon requires a long time to recover or may not be able to recover on its own, affecting the display effect of the OLED. Among them, the drift of the TFT threshold voltage / current is considered to be an important factor in the occurrence of afterimages. The drift of the TFT threshold voltage / current is more likely to occur in OLED devices using a highly heat-resistant flexible polyimide resin substrate. One of the reasons is that highly heat-resistant polyimide resin has a strong pp conjugation effect. The film material formed by it easily generates stimulated charges under light, especially low-wavelength light, forming a weak electric field, which interferes with the threshold voltage / current of the TFT circuit. The current common method is to add an external compensation circuit to try to stabilize the voltage or current across the OLED when the TFT threshold voltage / current drifts, so as to achieve normal switching of the OLED display screen and alleviate the OLED afterimage. However, this method cannot effectively solve the problem of afterimage in flexible OLEDs. Therefore, it is very necessary to improve the properties of the relevant materials above the TFT circuit, especially the planarization layer and the insulating layer materials, and reduce the impact of light emitted by the light-emitting device and natural light on the flexible TFT circuit.

[0005] Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems by providing a photosensitive resin composition, a cured film, and a display device. The cured film formed from the photosensitive resin composition, when used in flexible OLED devices to form a planarization layer or insulating layer material, can suppress TFT threshold voltage / current drift and prevent image retention. The cured film also exhibits good photosensitivity, a high residual film rate, high resolution, and excellent outgassing performance.

[0007] A first aspect of the present invention provides a photosensitive resin composition, comprising an alkali-soluble resin, a photosensitizer, and an organic solvent. A slurry of the photosensitive resin composition diluted 100 times has a transmittance of R1 at a wavelength λ1, and a transmittance of a cured film thereof at a wavelength λ2. The wavelengths λ1 and λ2 are within a range of 380 nm to 780 nm. When λ1 and λ2 are equal, the ratio of R1 to R2 is 0.0001 to 1.2.

[0008] The cured film is a film having a thickness of 1.5 μm obtained by curing a wet film at 250° C. for 1 hour after coating.

[0009] In some preferred embodiments of the present invention, the mass ratio N / S of nitrogen atoms to sulfur atoms in the cured film is 1.0 to 10.0, preferably 1.0 to 3.0, and more preferably 1.0 to 2.0.

[0010] In other preferred embodiments of the present invention, the mass ratio F / S of fluorine atoms to sulfur atoms in the cured film is 1.5 to 30.0, preferably 1.5 to 5.0.

[0011] In some preferred embodiments of the present invention, within the wavelength range of 380 nm to 450 nm, the maximum transmittance of the slurry of the photosensitive resin composition after being diluted 100 times is 55% to 65%.

[0012] In some preferred embodiments of the present invention, within the wavelength range of 480 nm to 780 nm, the minimum transmittance of the slurry of the photosensitive resin composition after being diluted 100 times is 80% to 85%.

[0013] Alternatively, the first aspect of the present invention provides a photosensitive resin composition, which includes an alkali-soluble resin, a photosensitizer and an organic solvent, and the mass ratio F / S of fluorine atoms to sulfur atoms in the cured film is 1.5 to 30.0, preferably 1.5 to 5.0; the cured film is a film with a thickness of 1.5 microns obtained by curing the wet film at 250°C for 1 hour after coating.

[0014] Preferably, the transmittance of the slurry after the photosensitive resin composition is diluted 100 times at a wavelength of λ1 is R1, and the transmittance of the cured film at a wavelength of λ2 is R2. The wavelengths λ1 and λ2 are in the range of 380nm to 780nm. When λ1 and λ2 are equal, the ratio of R1 to R2 is 0.0001 to 1.2.

[0015] Furthermore, the alkali-soluble resin includes a mixture of one or more of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, polybenzimidazole, polybenzimidazole precursor, polybenzothiazole, and polybenzothiazole precursor, preferably polyimide and / or polyimide precursor.

[0016] Furthermore, the alkali-soluble resin is prepared from a diamine monomer and a dianhydride monomer; the diamine monomer includes an aromatic diamine and / or an alicyclic diamine, and the aromatic diamine includes an amide bond-containing diamine and / or a phenolic hydroxyl group-containing diamine; the dianhydride monomer includes an aromatic dianhydride and / or an alicyclic dianhydride.

[0017] Furthermore, the amount of the diamine containing phenolic hydroxyl groups in the alkali-soluble resin accounts for more than 20% of the total molar amount of the diamine monomer, preferably more than 50%;

[0018] and / or, the amount of the dianhydride containing phenolic hydroxyl group accounts for 20% to 90% of the total molar amount of the dianhydride monomer;

[0019] And / or, the amount of the monomer containing an amide bond does not exceed 90% of the total molar amount of the dianhydride monomer and the diamine monomer, preferably does not exceed 50%.

[0020] Furthermore, the photosensitizer is an acid generator, preferably a diazonaphthoquinone compound.

[0021] Furthermore, the photosensitive resin composition further comprises any one or more of the following: a phenolic hydroxyl compound, a silane coupling agent or a surfactant.

[0022] Preferably, the organic solvent is a compound or a mixture having a boiling point greater than 100° C. under atmospheric pressure.

[0023] The second aspect of the present invention provides a cured film, which is obtained by coating, exposing, developing, and curing the positive photosensitive resin composition provided by the second aspect of the present invention.

[0024] A third aspect of the present invention provides a display device, comprising the cured film provided by the second aspect of the present invention.

[0025] Compared with the prior art, the present invention has the following beneficial effects: the photosensitive resin composition provided by the present invention, when used in flexible OLED devices to form planarization layer and insulating layer materials, can suppress TFT threshold voltage / current drift and avoid the occurrence of afterimages. At the same time, it also has good photosensitivity, high residual film rate, high resolution and excellent outgassing performance. DETAILED DESCRIPTION

[0026] The present invention provides a photosensitive resin composition, a cured film, and a display device. The present invention will be described below with reference to specific embodiments. It should be noted that the following examples are merely illustrative and are not intended to limit the present invention. Other combinations and modifications within the spirit or scope of the present invention are possible.

[0027] A first aspect of the present invention provides a photosensitive resin composition comprising an alkali-soluble resin, a photosensitizer, and an organic solvent. A slurry of the photosensitive resin composition diluted 100 times has a transmittance of R1 at a wavelength of λ1, and a transmittance of a cured film thereof at a wavelength of R2 at a wavelength of λ2. The wavelengths λ1 and λ2 are within a range of 380 nm to 780 nm. When λ1 and λ2 are equal, the ratio of R1 to R2 is 0.0001 to 1.2, such as 0.0001, 0.0005, 0.001, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, etc. The cured film is a film having a thickness of 1.5 microns obtained by curing a wet film at 250° C. for 1 hour after coating.

[0028] In other preferred embodiments, a photosensitive resin composition that satisfies the following conditions is preferred: a cured film obtained by coating the photosensitive resin composition and curing at 250°C for 1 hour, wherein the mass ratio of nitrogen atoms to sulfur atoms (N / S) of the cured film is 1.0 to 10.0, such as 1.0, 1.2, 1.4, 1.5, 1.6, 1.7, 1.8, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, etc., preferably 1.0 to 3.0, and more preferably 1.0 to 2.0. The nitrogen atoms in the cured film are derived from the alkali-soluble resin and other components such as the acid generator and the solvent remaining in the cured film, while the sulfur atoms are mainly derived from the acid generator naphthoquinone diazide compound and the alkali-soluble resin. It has been found that cured films that satisfy an N / S ratio of 1.0 to 10.0 have excellent outgassing properties. If the N / S value is too low, the outgassing properties of the cured film are poor.

[0029] For other preferred embodiments, the present invention provides a photosensitive resin composition that preferably meets the following conditions, that is, the photosensitive resin composition is coated and cured at 250°C for 1 hour to obtain a cured film, and the mass ratio F / S of fluorine atoms to sulfur atoms in the cured film is 1.5 to 30.0, such as 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, etc., and preferably 1.5 to 5.0. The fluorine atoms in the cured film mainly originate from the alkali-soluble resin, and the sulfur atoms mainly originate from the acid generator naphthoquinone diazide compound and the alkali-soluble resin. The photosensitive resin composition satisfying F / S of 1.5 to 30.0 has excellent resolution and outgassing properties.

[0030] In some other preferred embodiments, within the wavelength range of 380 nm to 450 nm, the maximum transmittance of the photosensitive resin composition slurry after being diluted 100 times is 55% to 65%. The photosensitive resin composition slurry meeting this range has better photosensitivity.

[0031] In some other preferred embodiments, within the wavelength range of 480 nm to 780 nm, the minimum transmittance of the photosensitive resin composition slurry after dilution by 100 times is 80% to 85%. The photosensitive resin composition slurry meeting this range has better photosensitivity.

[0032] Alternatively, the present invention provides another photosensitive resin composition, which includes an alkali-soluble resin, a photosensitizer and an organic solvent, and the mass ratio F / S of fluorine atoms to sulfur atoms in the cured film is 1.5 to 30.0, preferably 1.5 to 5.0; the cured film is a film with a thickness of 1.5 microns obtained by curing the wet film at 250°C for 1 hour after coating.

[0033] As a preferred embodiment, the transmittance of the slurry of the photosensitive resin composition diluted 100 times at a certain wavelength is R1, and the transmittance of the cured film at a certain wavelength is R2. In the range of 380nm to 780nm, the ratio of R1 to R2 at the same wavelength is 0.0001 to 1.2.

[0034] For the alkali-soluble resin in the aforementioned photosensitive resin composition of the present invention, including one or more mixtures of polyimide, polyimide precursor, polybenzoxazole, and polybenzoxazole precursor. Wherein the polyimide precursor refers to the reaction product of a diamine monomer and a tetracarboxylic dianhydride monomer, including polymers such as polyamic acid and polyamic acid ester, which can be dehydrated and cyclically closed to form an imide bond to obtain a polyimide by high-temperature curing. A polybenzoxazole precursor refers to a bisaminophenol compound as a diamine reacted with a dicarboxylic acid, a corresponding dicarboxylic acid dichloride or a dicarboxylic acid active diester, and an example of polyhydroxyamide can be cited. Dehydration and cyclic closure can be achieved by heating and other means to form a rigid benzoxazole ring to obtain a polybenzoxazole.

[0035] There is no particular restriction on the preparation process of the alkali-soluble resin, as long as the resin can be obtained. For the polyimide precursor, diamine and tetracarboxylic dianhydride are usually directly added to a solvent for polymerization reaction. The solvent used is not particularly limited, and examples thereof include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, dimethyl sulfoxide, tetrahydrofuran, diethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol methyl ethyl ether, acetone, methyl ethyl ketone, diisobutyl ketone, diacetone alcohol, cyclohexanone, propylene glycol monomethyl ether acetate, etc. Based on the total amount of the polyimide precursor solution, the mass proportion of the organic solvent is generally 50 to 95%, preferably 70 to 90%. The conditions of the polymerization reaction are not particularly limited, and the reaction is usually carried out in an inert atmosphere at -10°C to 80°C for 2 to 48 hours. For the preparation of polyimide, polyimide is obtained by imidization of a polyimide precursor, and examples of thermal imidization or chemical imidization can be cited. Specifically, thermal imidization refers to stirring a polyimide precursor solution at a temperature above 100°C, preferably 150 to 350°C, for 0.5 to 72 hours to carry out an imidization reaction. Chemical imidization refers to adding a chemical imidizing agent such as an acid anhydride such as acetic anhydride, propionic anhydride or benzoic anhydride, and an amine compound such as pyridine, isoquinoline, triethylamine to a polyimide precursor solution to carry out an imidization reaction; relative to the number of amic acids in the system, the dehydrating agent used is preferably 0.1 to 0.8 mol%. The preparation process of polybenzoxazole precursor and polybenzoxazole will not be described in detail, and methods known in the art can be used.

[0036] The alkali-soluble resin described in the present invention is a polyimide and / or a polyimide precursor, which is prepared from a diamine monomer and a dianhydride monomer; the diamine monomer includes an aromatic diamine and / or an alicyclic diamine, and the aromatic diamine includes an amide bond-containing diamine and / or a phenolic hydroxyl group-containing diamine; the dianhydride monomer includes an aromatic dianhydride and / or an alicyclic dianhydride.

[0037] For some preferred alkali-soluble resins, the amount of the diamine containing a phenolic hydroxyl group in the alkali-soluble resin accounts for more than 20% of the total molar amount of the diamine monomer, preferably more than 50%, such as 60%, 65%, 70%, 75%, 80%, etc.; and / or the amount of the dianhydride containing a phenolic hydroxyl group accounts for 20% to 90% of the total molar amount of the dianhydride monomer, such as 30%, 40%, 50%, etc.;

[0038] And / or, the amount of the monomer containing an amide bond does not exceed 90% of the total molar amount of the dianhydride monomer and the diamine monomer, preferably does not exceed 50%.

[0039] By adjusting the proportion of phenolic hydroxyl groups and amide bonds to regulate the coating of the photosensitive resin composition and rapid development after exposure, production efficiency is improved.

[0040] The aforementioned diamine containing a phenolic hydroxyl group, diamine containing an amide bond, or diamine monomer containing both a phenolic hydroxyl group and an amide bond can be exemplified below. The following diamine monomers can be used alone or in combination of two or more.

[0041] The aforementioned dianhydride containing a phenolic hydroxyl group, dianhydride containing an amide bond, or dianhydride monomer containing both a phenolic hydroxyl group and an amide bond may be exemplified by the dianhydride formed by the following tetracarboxylic acid examples. The dianhydride monomer formed by dehydration of the following tetracarboxylic acid examples may be used alone or in combination of two or more.

[0042] Examples of the diamine monomers containing no phenolic hydroxyl group and / or amide bond include p-phenylenediamine, m-phenylenediamine, benzylenediamine, 2-(3-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-5-aminobenzoxazole, 2,5-bis(4-aminophenyl)pyrimidine, m-methylenedianiline, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, bis(3-aminophenyl)sulfone, 2,3 , one or more of 5,6-tetraaminopyridine, 1,4-bis(2-trifluoromethyl-4-aminophenoxy)benzene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, p-methylenedianiline, 1,3-bis(3-aminophenoxy)benzene, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(3-aminophenyl)hexafluoropropane, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane and 4,4'-bis(3-aminophenoxy)diphenyl sulfone.

[0043] Examples of the dianhydride monomer containing no phenolic hydroxyl group and / or amide bond include one or more of 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3,'4'-biphenyltetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-diphenylketonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 2,3'3,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone dianhydride and 4,4-oxydiphthalic dianhydride.

[0044] As a preferred embodiment, a monomer containing both fluorine and a phenolic hydroxyl group may be selected so as to adjust the solubility of the alkali-soluble resin and the F / S ratio in the cured film at the same time.

[0045] At the same time, in order to better adjust the molecular weight of the polyimide resin precursor of the present invention, a certain end-capping agent can be added during polymerization. Specific examples thereof include but are not limited to the following exemplary compounds.

[0046] Monoamine compounds: 3-aminophenol, 2-aminophenol, 4-aminophenol, 3-aminobenzoic acid, 3-amino-o-methylbenzoic acid, 3-amino-m-methylbenzoic acid, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 1-amino-8-hydroxynaphthalene, 1-amino-7-hydroxynaphthalene, 1-amino-6-hydroxynaphthalene, 1-amino-5-hydroxynaphthalene, 1-amino-4-hydroxynaphthalene, 1-amino-3-hydroxynaphthalene, 1-amino-2 -hydroxynaphthalene, 1-carboxy-8-aminonaphthalene, 1-carboxy-7-aminonaphthalene, 1-carboxy-6-aminonaphthalene, 1-carboxy-5-aminonaphthalene, 1-carboxy-4-aminonaphthalene, 1-carboxy-3-aminonaphthalene, 1-carboxy-2-aminonaphthalene, 3-amino-4,6-dihydroxypyrimidine, 5-amino-8-hydroxyquinoline, 4-amino-8-hydroxyquinoline, N-(4-aminophenyl)maleimide, N-(3-aminophenyl)maleimide.

[0047] Monofunctional acid anhydride compounds: maleic anhydride, phthalic anhydride, cyclohexanedicarboxylic anhydride, cyclohexanepentanedicarboxylic anhydride and the like.

[0048] The end-capping agent is preferably selected from the group consisting of N-(4-aminophenyl)maleimide, N-(3-aminophenyl)maleimide, and maleic anhydride, which have unsaturated olefinic bonds, based on the balance between solubility contrast and heat resistance of the resulting polyimide resin precursor in a developer. The end-capping agent is preferably introduced in an amount of 0.5 mol% to 50 mol%, and more preferably 1 mol% to 40 mol%, based on the total molar amount of all amino and anhydride monomers introduced. By maintaining the end-capping agent within this range, a resin composition having a moderate solution viscosity and excellent film properties can be obtained.

[0049] For the photosensitizer in the photosensitive resin composition, an acid generator such as a diazonaphthoquinone compound is preferred. The addition amount is 5%-40% of the mass of the alkali-soluble resin, preferably 10%-30%. Examples can be given: one or more of diazonaphthoquinone compounds (diazonaphthoquinone sulfonate compounds), sulfonium salts, phosphonium salts, diazonium salts, iodonium salts, etc.; these diazonaphthoquinone compounds can be synthesized by esterification reaction of the following compounds with diazonaphthoquinone sulfonyl chloride. In the present invention, the diazonaphthoquinone compound preferably uses a compound obtained by bonding 5-diazonaphthoquinone sulfonyl and 4-diazonaphthoquinone sulfonyl to the following compounds. Among them, the compounds used to synthesize diazonaphthoquinone compounds include the following examples:

[0050] As the diazonaphthoquinone compound, it is preferable that the molecular structure has any one or more combinations of diazonaphthoquinone sulfonate structures.

[0051] Specifically, the following commercial photoacid generators PAC-1 to PAC-20 can be used. Any one or more of the following substances can be used in combination. Photoacid generators containing both F and S are also preferred in order to adjust the F / S ratio of the cured film.

[0052] Regarding the solvent in the photosensitive resin composition, the organic solvent is a compound or mixture having a boiling point greater than 100°C at atmospheric pressure. In other words, the solvent in the photosensitive resin composition of the first aspect of the present invention is a single organic solvent or a mixture of multiple organic solvents. Examples include one or more of γ-butyrolactone, methyl lactate, ethyl lactate, butyl lactate, bis(2-methoxyethyl) ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, cyclopentanone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, propyl acetate, butyl acetate, butanol, isobutanol, amyl alcohol, N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. Preferably, the solvent has a boiling point greater than 100°C at atmospheric pressure. A solvent with a boiling point that is too high is not conducive to drying the photosensitive resin composition after coating; a solvent with a boiling point that is too low has poor solubility, which is not conducive to uniform coating of the photosensitive resin composition. The amount of the solvent added is 1 to 50 times, more preferably 3 to 30 times, the mass of the alkali-soluble resin used.

[0053] The photosensitive resin composition provided in the first aspect of the present invention may further include any one or more of the following: a phenolic hydroxyl compound, a silane coupling agent, or a surfactant.

[0054] The phenolic hydroxyl compound in the photosensitive resin composition improves development and produces high-resolution patterns. The phenolic hydroxyl compound is added in an amount ranging from 0.1% to 50% by weight of the alkali-soluble resin. The following examples are provided. The phenolic hydroxyl compounds listed below can be used singly or in combination. By adjusting the phenolic hydroxyl group in the alkali-soluble resin and the phenolic hydroxyl compound, the solubility of the photosensitive resin composition and the coating film can be adjusted simultaneously.

[0055] The silane coupling agent in the photosensitive resin composition is used to improve the adhesion between the cured film of the photosensitive resin composition and other film layers. The amount added is 0.001-10% of the total mass of the photosensitive resin composition. The following examples can be given:

[0056] Surfactants in the photosensitive resin composition are beneficial for obtaining a photosensitive resin composition with excellent leveling properties. The surfactant is added in an amount of 0.001-10% of the total mass of the photosensitive resin composition. Examples include one or more of polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, sorbitan monostearate, silicone surfactants, and fluorosurfactants.

[0057] The photosensitive resin composition provided in the first aspect of the present invention may further include a thermal crosslinking agent. The thermal crosslinking agent undergoes a cross-linking reaction with the alkali-soluble resin upon heating, thereby improving the chemical resistance of the cured film. The thermal crosslinking agent is selected from one or more of epoxy compounds and alkoxy / hydroxymethyl compounds. The thermal crosslinking agent is added in an amount of 10% to 60% of the total mass of the alkali-soluble resin, preferably 20% to 50%.

[0058] Among them, the epoxy compound used as a thermal crosslinking agent is preferably a compound containing two or more epoxy groups in one molecule, and examples thereof include bisphenol A epoxy resin, hexafluorobisphenol A epoxy resin, bisphenol A oxetane resin, bisphenol F epoxy resin, bisphenol F oxetane resin, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polymethyl (glycidyloxypropyl) siloxane and other epoxy-containing silicones, but are not limited to these. Specific examples include Dainippon Ink and Chemicals EPICLON, EXA and other series products, Yuka Shell Epoxy Co. Ltd's Epikote series of bisphenol A epoxy compounds and ADEKA's EP series. Examples include Dainippon Ink & Chemicals' EPICLON and EXA series products, such as EPICLON 850-S, EPICLON HP-4032, EPICLON HP-7200, EPICLON HP-820, EPICLON HP-4700, EPICLON EXA-4710, EPICLON HP-4770, EPICLON EXA-4816, EPICLON EXA-4822, and ADEKA's EP series such as EP-4003S and EP-4000S.

[0059] Alkoxy / hydroxymethyl compounds used as thermal crosslinking agents preferably contain two or more alkoxy and / or hydroxymethyl functional groups per molecule, with a total of 2-8 functional groups. Examples include phenolic compounds such as (2-hydroxy-5-methyl)-1,3-benzenedimethanol and 2,2',6,6'-tetramethoxymethylbisphenol A. Examples include Honshu Chemical's DML, TriML, DMOM, HMOM, and TMOM series, such as DML-PC, DML-PEP, DML-OC, DML-OEP, DMOM-PC, and DMOM-PTBP, and Sanwa Chemical's MX and MW series, such as MX-270 and MW-100LM.

[0060] Furthermore, the photosensitive resin composition of the present invention may contain a thermal acid generator within a range not impairing the effects of the present invention.

[0061] Specific examples of preferably used thermal acid generators include SI-60, SI-80, SI-100, SI-110, SI-145, SI-150, SI-60L, SI-80L, SI-100L, SI-110L, SI-145L, SI-150L, ​​SI-160L, and SI-180L (all manufactured by Sanshin Chemical Industry Co., Ltd.), 4-hydroxyphenyldimethylsulfonium, benzyl-4-hydroxyphenylmethylsulfonium, 2-methylbenzyl-4-hydroxyphenylmethylsulfonium, 2-methylbenzyl-4-acetylphenylmethylsulfonium, 2-methylbenzyl-4-benzoyloxyphenylmethylsulfonium, and their methanesulfonates, trifluoromethanesulfonates, camphorsulfonates, and p-toluenesulfonates. More preferred are 4-hydroxyphenyldimethylsulfonium, benzyl-4-hydroxyphenylmethylsulfonium, 2-methylbenzyl-4-hydroxyphenylmethylsulfonium, 2-methylbenzyl-4-acetylphenylmethylsulfonium, 2-methylbenzyl-4-benzoyloxyphenylmethylsulfonium, and their methanesulfonates, trifluoromethanesulfonates, camphorsulfonates, and p-toluenesulfonates. It should be noted that the above compounds may be used alone or in combination of two or more.

[0062] The amount of the thermal acid generator added is 0.01% to 10% by weight, more preferably 0.01% to 0.5% by weight, based on the mass of the alkali-soluble resin. If the amount is less than 0.01%, the crosslinking accelerator function cannot be fully exerted, resulting in a low hardness film. If the amount is more than 10% by weight, sensitivity may be reduced or the mechanical or electrical properties of the cured film may be deteriorated.

[0063] The second aspect of the present invention provides a cured film obtained from the photosensitive resin composition provided by the first aspect of the present invention, obtained by coating, exposing, developing, and curing. Furthermore, the cured film is obtained by coating, pre-baking, exposing, post-baking, developing, and curing.

[0064] The coating step involves coating the photosensitive resin composition on a substrate. Examples of coating methods include spin coating, spray coating, blade coating, screen coating, and slit coating. The film thickness after drying is preferably 0.5 to 50 μm. Drying is performed using an oven, hot plate, infrared oven, etc., at a temperature between 40°C and 80°C for 1 to 10 minutes or by performing a step-by-step temperature-programmed drying process to volatilize the organic solvent. Examples of substrates include, but are not limited to, silicon wafers, ceramics, gallium arsenide, organic circuit boards, inorganic circuit boards, and substrates containing circuit components disposed thereon.

[0065] The pre-baking step has a pre-baking temperature of 70 to 130° C., such as 70 to 100° C. or 100 to 130° C. The pre-baking time is 1 to 5 minutes.

[0066] The exposure step is carried out after a photosensitive resin composition film is formed on a substrate by coating and drying. The film is irradiated with exposure light under a mask having a desired pattern for exposure. The exposure light source preferably uses i (365nm), h (405nm), and g (436nm) rays of a mercury lamp. The exposure device uses a reduced projection exposure device, a mask aligner, a mirror projection exposure device, etc.

[0067] In the post-baking step, the post-baking temperature is 70-130° C., such as 70-110° C. or 110-130° C.; preferably 110° C.; the post-baking time is 1-3 min, such as 1-2 min or 2-3 min; preferably 2 min.

[0068] In the development step, a developer is used to remove the exposed portions of the film. Preferred developers include aqueous solutions of alkaline compounds such as tetramethylammonium hydroxide, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, dimethylamine, dimethylaminoethanol, cyclohexylamine, and ethylenediamine. Additionally, one or more organic solvents such as N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol, ethyl lactate, cyclopentanone, cyclohexanone, and acetone can be added to these alkaline aqueous solutions.

[0069] The developing method is selected from one of spray developing, immersion developing, and ultrasonic immersion developing methods; the developing time, developing temperature, developing steps and other conditions are sufficient to remove the exposed part; after development, the developed film is preferably rinsed with water, and more preferably rinsed with an aqueous solution of alcohol or ester such as ethanol, isopropanol, or ethyl lactate; if necessary, the film is baked before development, the baking temperature is 50-150°C, preferably 50-120°C, and the baking time is 5s-60min; after rinsing, the film is heated and dried in the range of 50-200°C, and the drying time is controlled to be 1min-60min.

[0070] In the curing step, the curing temperature is 230-270° C., such as 250° C., and the curing time is 1 hour. A patterned cured film can be obtained by curing.

[0071] The cured film having a desired pattern formed from the positive photosensitive resin composition of the present invention can be used as a surface protective film of a semiconductor element, an interlayer insulating film, an insulating layer of an organic electroluminescent (EL) element, an insulating layer of a thin film transistor (TFT), etc., but is not limited thereto.

[0072] <Display device>

[0073] A third aspect of the present invention provides a display device comprising the cured film provided by the second aspect of the present invention. Furthermore, the display device includes, but is not limited to, flexible displays such as OLEDs and TFT-LCDs. The cured film of the present invention can be used in the insulating layer, pixel definition layer, planarization layer of a flexible display, and / or in the surface protection layer or insulating layer of a semiconductor device.

[0074] Example

[0075] The above and other advantages of the present invention may be better understood through the following examples, but the following examples are not intended to limit the scope of the present invention.

[0076] [Corrected 16.10.2024 according to Rule 26] Table 1 Description of reference numbers

[0077] The synthesis method of monomers a4, a5, and a6 refers to patent CN112180685A;

[0078] Monomer b5 is a bis-trimellitic anhydride derivative of 4,6-diaminoresorcinol;

[0079] Monomer b6 is a bis-trimellitic anhydride derivative of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane;

[0080] Monomer b7 is a bis-trimellitic anhydride derivative of 5,5′-oxybis(2-aminophenol).

[0081] <Alkali-soluble resin>

[0082] Synthesis Examples 1-12 and 01-03

[0083] According to the raw material types and amounts listed in Table 2, a diamine compound, a dianhydride compound, and a capping agent were dissolved in a solvent under a dry nitrogen stream. The mixture was stirred at room temperature for 24 hours, then heated to 150°C and reacted for 6 hours. The solution was then poured into 2 liters of ethanol, and the polymer solid precipitate was collected by filtration. The polymer solid was dried in a vacuum oven at 60°C for 24 hours to obtain alkali-soluble resins A1-A12 and A01-A03.

[0084] Table 2 Types and amounts of raw materials used in Synthesis Examples 1-12 and 01-03

[0085] <Photosensitive resin composition>

[0086] Examples 1-12 and Comparative Examples 1-3

[0087] According to the types and amounts of raw materials listed in Table 3, a photoacid generator, a phenolic hydroxyl group-containing compound, a silane coupling agent, a surfactant and a solvent were added to the alkali-soluble resin to prepare a varnish, thereby obtaining the photosensitive resin composition slurry of the present invention.

[0088] [Corrected 16.10.2024 according to Rule 26] Table 3 Types and amounts of raw materials for Examples 1-12 and Comparative Examples 1-3

[0089] <Preparation of Cured Film>

[0090] The photosensitive resin composition varnish obtained in Examples 1-11 and Comparative Examples 1-3 was coated on a glass substrate using a spin coater to form a coating film. After pre-baking at 80° C., it was heated in an oven at 250° C. for 60 minutes to obtain a cured film of 1.5±0.1 μm.

[0091] The mass ratios of fluorine to sulfur (F / S, N / S) of the cured films of the positive photosensitive resin composition slurries obtained in Examples 1-11 of the present invention and Comparative Examples 1-3, and the transmittance ratios of the slurries diluted 100 times to the cured films at the same wavelength were measured, to obtain the data in Tables 4-6.

[0092] Test method:

[0093] F / S mass ratio and N / S mass ratio: The F content in the cured film was determined using ion chromatography in accordance with EN 14582:2016. The elemental content in the 1.5-μm cured film was determined using a Thermo Fisher Scientific FlashSmart organic elemental analyzer in a dual-combustion furnace capable of measuring CHNSO percentages. A 50 mg sample was injected and decomposed by catalytic oxidation. After interference removal, the resulting gas mixture was separated by a chromatographic column and detected by a thermal conductivity detector. Helium was used as the carrier and purge gas to determine the N and S contents. The fluorine to sulfur ratio was calculated to obtain the F / S ratio, and the nitrogen to sulfur ratio was calculated to obtain the N / S ratio.

[0094] Transmittance test: The 1.5 μm cured film was tested using a Shimadzu UV 3600 spectrophotometer according to GB / T 2680-94. The transmittance was recorded and the average of three test results was taken.

[0095] Table 4 Element mass ratios of the slurries obtained in Examples 1-12 and Comparative Examples 1-3 corresponding to the cured films

[0096] Table 5 Transmittance of the slurries obtained in Examples 1-12 and Comparative Examples 1-3 after dilution 100 times

[0097] Table 6 Transmittance ratio of the slurry diluted 100 times to the cured film at the same wavelength in Examples 1-12 and Comparative Examples 1-3

[0098] The corresponding cured films of the positive photosensitive resin compositions obtained in Examples 1-12 of the present invention and Comparative Examples 1-3 were evaluated, and the data in Table 7 were obtained:

[0099] Table 7 Performance evaluation of the cured films of the positive photosensitive resin compositions obtained in Examples 1-12 of the present invention and Comparative Examples 1-3

[0100] <Evaluation Method>

[0101] Minimum irradiation dose: Using a coating and developing device, the photosensitive resin composition slurry was spin-coated onto a 6-inch silicon wafer and pre-baked at 120°C for 2 minutes. Exposure was performed using an i-line stepper. After exposure, the wafer was developed with a 2.38 wt% tetramethylammonium hydroxide (TMAH) aqueous solution for 60 seconds. After rinsing with pure water and drying, the lowest exposure dose at which the exposed portion was completely dissolved was used as the sensitivity.

[0102] Residual film rate: The photosensitive resin compositions prepared in Examples 1-9 and Comparative Examples 1-3 were coated on a 6-inch silicon wafer to a pre-baked film thickness of 10 μm. The pre-baked film was then pre-baked at 120°C for 4 minutes using a hot plate (SCW-636; Dainippon Screen Manufacturing Co., Ltd.). A small photolithography developer (AC3000) was used with exposure doses of 0 to 1000 mJ / cm² on the i, g, and h lines. 2 In the case of 10mJ / cm 2 The film was exposed with a step length of 100 nm. After exposure, the film was developed in a 2.38 mass% TMAH aqueous solution for 90 seconds and then rinsed with water to obtain a developed film with an isolated pattern. Calculation of residual film rate: Residual film rate (%) = film thickness after development ÷ film thickness after pre-baking × 100%

[0103] Afterimage evaluation: A photosensitive resin composition slurry is applied to the planarization layer of an OLED display. The afterimage of the OLED display is measured. The measurement conditions are as follows: after aging the OLED display for 60 minutes using a black and white checkerboard pattern, the screen is switched to a specific grayscale image, and the presence of checkerboard point afterimages is observed with the naked eye. If the checkerboard point afterimage disappears within 5 minutes after switching, it is considered excellent; if the checkerboard point afterimage disappears within 5-30 minutes after switching, it is considered good; if the checkerboard point afterimage persists for more than 30 minutes after switching, it is considered poor.

[0104] Resolution: A film obtained by applying a positive-type photosensitive resin composition slurry was pattern-exposed using a double-sided alignment single-sided exposure system (Mask Aligner PEM-6M; manufactured by Union Optical Co., Ltd.) through a grayscale mask for sensitivity measurement (MDRM MODEL 4000-5-FS; manufactured by OptoLine International) using the i-line (wavelength 365nm), h-line (wavelength 405nm), and g-line (wavelength 436nm) of an ultra-high-pressure mercury lamp. The resulting film was then developed using a small-sized developer for photolithography (AD-2000; manufactured by Takizawa Sangyo Co., Ltd.). The developed film was then cured using a high-temperature inert oven (INH-9CD-S; manufactured by Koyo Thermo Systems Co., Ltd.) to obtain a cured film. The resolved pattern of the cured film was observed using an FPD / LSI inspection microscope (OPTIPHOT-330; manufactured by Union Co., Ltd.). The minimum pattern size of the line and space pattern obtained without residue was defined as the resolution.

[0105] Outgassing evaluation: A positive-type photosensitive resin composition slurry was evenly applied to a glass substrate using a knife coater and pre-baked on a hot plate at 90°C for 120 seconds to volatilize the solvent, forming a photosensitive resin composition layer with a thickness of 3.0 μm. The resulting photosensitive resin composition layer was then exposed using a Canon MPA 5500CF (high-pressure mercury lamp) through a predetermined mask. The exposed photosensitive resin composition layer was then developed using an alkaline developer (0.4% tetramethylammonium hydroxide aqueous solution) at 23°C for 60 seconds and then rinsed with ultrapure water for 20 seconds. The layer was then baked in an oven at 250°C for 60 minutes. The obtained cured film was scraped off and the weight loss was analyzed using a thermogravimetric analyzer (TGA) (Q-5000SA, manufactured by TA Instruments) under the conditions of a heating rate of 10°C / min, a holding temperature of 250°C, a holding time of 30 minutes, and a nitrogen atmosphere.

Claims

1. A photosensitive resin composition, wherein The photosensitive resin composition comprises an alkali-soluble resin, a photosensitizer and an organic solvent. The transmittance of the slurry of the photosensitive resin composition diluted 100 times at a wavelength λ1 is R1, and the transmittance of the cured film at a wavelength λ2 is R2. The wavelengths λ1 and λ2 are within the range of 380nm to 780nm. When λ1 is equal to λ2, the ratio of R1 to R2 is 0.0001 to 1.

2. The cured film is a film having a thickness of 1.5 microns obtained by curing a wet film at 250° C. for 1 hour after coating.

2. The photosensitive resin composition according to claim 1, wherein The mass ratio N / S of nitrogen atoms to sulfur atoms in the cured film is 1.0 to 10.0, preferably 1.0 to 3.0, and more preferably 1.0 to 2.

0.

3. The photosensitive resin composition according to claim 1 or 2, wherein The mass ratio F / S of fluorine atoms to sulfur atoms in the cured film is 1.5 to 30.0, preferably 1.5 to 5.

0.

4. The photosensitive resin composition according to any one of claims 1 to 3, wherein In the wavelength range of 380nm to 450nm, the maximum transmittance of the slurry of the photosensitive resin composition after being diluted 100 times is 55% to 65%.

5. The photosensitive resin composition according to any one of claims 1 to 3, wherein In the wavelength range of 480nm to 780nm, the minimum transmittance of the slurry of the photosensitive resin composition after being diluted 100 times is 80% to 85%.

6. A photosensitive resin composition, wherein: The photosensitive resin composition includes an alkali-soluble resin, a photosensitizer and an organic solvent. The mass ratio F / S of fluorine atoms to sulfur atoms in the cured film is 1.5 to 30.0, preferably 1.5 to 5.

0. The cured film is a film with a thickness of 1.5 microns obtained by curing the wet film at 250° C. for 1 hour after coating.

7. The photosensitive resin composition according to claim 6, wherein The transmittance of the slurry of the photosensitive resin composition diluted 100 times at wavelength λ1 is R1, and the transmittance of the cured film at wavelength λ2 is R2. The wavelengths λ1 and λ2 are in the range of 380nm to 780nm. When λ1 and λ2 are equal, the ratio of R1 to R2 is 0.0001 to 1.

2.

8. The photosensitive resin composition according to claim 1 or 6, wherein The alkali-soluble resin includes a mixture of one or more of polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, polybenzimidazole, polybenzimidazole precursor, polybenzothiazole, and polybenzothiazole precursor, preferably polyimide and / or polyimide precursor.

9. The photosensitive resin composition according to claim 1 or 6, wherein The alkali-soluble resin is a polyimide and / or a polyimide precursor, which is prepared from a diamine monomer and a dianhydride monomer; the diamine monomer includes an aromatic diamine and / or an alicyclic diamine, and the aromatic diamine includes an amide bond-containing diamine and / or a phenolic hydroxyl-containing diamine; the dianhydride monomer includes an aromatic dianhydride and / or an alicyclic dianhydride.

10. The photosensitive resin composition according to claim 9, wherein The amount of the diamine containing phenolic hydroxyl groups in the alkali-soluble resin accounts for more than 20% of the total molar amount of the diamine monomers, preferably more than 50%; and / or, the amount of the dianhydride containing phenolic hydroxyl group accounts for 20% to 90% of the total molar amount of the dianhydride monomer; And / or, the amount of the monomer containing an amide bond does not exceed 90% of the total molar amount of the dianhydride monomer and the diamine monomer, preferably does not exceed 50%.

11. The photosensitive resin composition according to claim 1 or 6, wherein The photosensitizer is an acid generator, preferably a diazonaphthoquinone compound.

12. The photosensitive resin composition according to claim 1 or 6, wherein The photosensitive resin composition further comprises any one or more of the following: a phenolic hydroxyl compound, a silane coupling agent or a surfactant.

13. The photosensitive resin composition according to claim 1 or 6, wherein The organic solvent is a compound or a mixture, and the boiling point under atmospheric pressure is greater than 100°C.

14. A cured film, wherein: The photosensitive resin composition according to any one of claims 1 to 13 is obtained by coating, exposing, developing and curing.

15. A display device, wherein: The cured film according to claim 14 is included.

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