Low-temperature-curing low-thermal-expansion photosensitive polyimide resin and photoresist thereof

Abstract

The invention provides low-temperature-curing low-thermal-expansion photosensitive polyimide resin which is characterized in that the low-temperature-curing low-thermal-expansion photosensitive polyimide resin has a structure shown in a formula I. In the formula I, X is a residue of polyamic acid ester polymerized tetracarboxylic dianhydride; y at least comprises a group of a nitrogen-containing aromatic heterocyclic structure; r1 is a group of a C4-C20 polymerizable olefin structure; r2 is a straight chain or branched chain alkane group of C1-C12, or a straight chain or branched chain alkane group containing an ether bond-O-; m at least comprises one of amido and anhydride; n is the degree of polymerization, and n is equal to 2-150. The photosensitive polyimide resin provided by the invention simultaneously contains an allyl side chain and a fat side chain, the main chain contains a nitrogen-containing aromatic heterocyclic ring, and the aims of low curing temperature, low thermal expansion coefficient, high adhesive force with a copper substrate and resolution of cyclopentanone development can be simultaneously achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyimide, and particularly relates to a low-temperature curing, low-thermal expansion photosensitive polyimide resin and a photoresist thereof. BACKGROUND

[0002] Polyimide has excellent heat resistance, insulation and chemical resistance. It is widely used as an insulating material for electronic devices, and as a passivation film, a surface protective film and an interlayer insulating film for semiconductor devices. A photosensitive polyimide is obtained by imparting photosensitivity to polyimide, and a photoresist composition containing the photosensitive polyimide and a photosensitizer and the like. By coating, exposing, developing and heat curing (imidization) based on curing processes, patterning of polyimide can be achieved. By using the photosensitive polyimide, the process can be greatly shortened compared to the case of using a non-photosensitive polyimide.

[0003] In recent years, with the miniaturization and high performance of various electronic devices such as personal computers, digital cameras, mobile phones, etc., semiconductor components have also rapidly increased in demand for smaller, thinner and higher density. Therefore, from the viewpoint of improving integration and arithmetic function, the semiconductor packaging structure is changing. High-density mounting technologies such as wafer size packaging or wafer scale packaging three-dimensional laminates are rapidly developing. In such advanced packaging technologies, photosensitive polyimide capable of forming patterns on substrates is attracting attention for its insulating properties, mechanical strength, thermal expansion properties and adhesion to substrates as a protective film, an insulating layer, a dielectric layer.

[0004] Previously, for photosensitive polyimide-based materials, polyamide acid derivatives, which are precursors of polyimide, were used, for example, a photosensitive group was introduced by an ester bond from the carboxyl group of polyamide acid. However, after patterning, imidization treatment at a high temperature of more than 300°C is required to obtain the target polyimide. This high temperature can affect the base substrate or oxidize the copper wiring. Therefore, there is a demand for reducing the curing temperature.

[0005] The application of photosensitive polyimide as an insulating layer or a dielectric layer in the semiconductor manufacturing process undergoes a temperature of about 260°C in the solder reflow process. In this reflow process, the photosensitive polyimide layer will come into contact with the wafer substrate and copper wiring, and in multi-layer stacked packages, large stress will be generated between the photosensitive polyimide layer and the substrate and copper due to thermal expansion mismatch. There will be problems such as insufficient adhesion and delamination. Therefore, there is a need to reduce the thermal expansion coefficient of the photosensitive polyimide, increase the adhesion to copper, and inhibit the migration of copper ions.

[0006] Therefore, with the development of high density and high integration of chips, the pattern of polyimide as the insulating medium layer of RDL re-routed technology should also be increasingly developed, at the same time, it needs to be cured at a temperature below 200 degrees, still can maintain a low thermal expansion coefficient, and has sufficient mechanical strength, and adhesion to copper.

[0007] At the same time, the selection of developing solvent for low temperature curing, the boiling point below the curing temperature requirements, and the environmental protection requirements. In the use of low temperature curing, encourage the use of industry conventional cyclohexanone as developer, rather than for low temperature curing, and the use of N-methyl-2-pyrrolidone (NMP) development, in the European REACH rules, NMP list in SVHC (license object candidate substance). For these reasons, N-methyl-2-pyrrolidone is the solvent to be avoided as much as possible.

[0008] Therefore, to provide a photoresist which can achieve low curing temperature, low thermal expansion coefficient, high adhesion to copper substrate, and high resolution effect when developed in cyclopentanone becomes a problem to be solved. SUMMARY

[0009] Therefore, the technical problem to be solved by the present application is to provide a low temperature curing, low thermal expansion photosensitive polyimide resin and its photoresist. The photoresist provided by the present application can achieve low curing temperature, low thermal expansion coefficient, high adhesion to copper substrate, and high resolution effect when developed in cyclopentanone.

[0010] The present application provides a low temperature curing, low thermal expansion photosensitive polyimide resin, having the structure shown in formula I:

[0011]

[0012] In formula I, X is the residue of a tetracarboxylic dianhydride polymerized by polyamide acid ester;

[0013] Y contains at least a nitrogen-containing aromatic heterocyclic structure group;

[0014] R1 is a C4-C20 polymerizable olefin structure group;

[0015] R2 is a C1-C12 straight chain or branched alkyl group, or a straight chain or branched alkyl group containing an ether bond -O-;

[0016] M contains at least one of amine group and anhydride group;

[0017] n is the degree of polymerization, n = 2-150.

[0018] Preferably, X includes at least one of the following groups:

[0019]

[0020]

[0021] Preferably, X comprises at least one of the following groups:

[0022]

[0023] Preferably, Y comprises at least one of the following groups:

[0024]

[0025] Preferably, Y comprises at least one of the following groups:

[0026]

[0027]

[0028] Preferably, Y further comprises a group without nitrogen heterocyclic structure, the group without nitrogen heterocyclic structure comprising at least one of the following groups:

[0029]

[0030] The molar amount of the group with nitrogen-containing aromatic heterocyclic structure accounts for > 60% of the total molar amount of the group Y.

[0031] Preferably, R1 comprises at least one of the following groups:

[0032]

[0033] R2 is selected from at least one of C4-C8 linear or branched alkyl group, methoxy-containing linear or branched alkyl group.

[0034] Preferably, M comprises at least one of amine group and anhydride group, and M is selected from one of the following groups:

[0035]

[0036] Z is -O-, -COO-, -NH-;

[0037] R3 is C1-C12 linear or branched alkyl group, or linear or branched alkyl group containing ether bond -O-.

[0038] Preferably, the weight average molecular weight of the photosensitive polyimide resin is (0.5-10) x 10 4 .

[0039] The application also provides a preparation method of the above low-temperature curing, low-thermal expansion photosensitive polyimide resin, comprising the following steps:

[0040] A) mixing and reacting a dianhydride compound, a primary alcohol containing R1, a primary alcohol containing R2, and a catalyst in the presence of a solvent to obtain a diacid diester reaction solution;

[0041] B) adding an activating agent to the diacid diester reaction solution to obtain a reaction system;

[0042] C) adding a diamine compound and an end capping agent A-M to the reaction system to obtain a photosensitive polyimide resin.

[0043] Preferably, in step A), the temperature of the reaction is <20℃, and the reaction time is 4-24h;

[0044] In step B), the temperature of the reaction is <20℃, and the reaction time is 0.5-4h;

[0045] In step C), the temperature of the reaction is <20℃, and the reaction time is 4-24h;

[0046] The solvent is selected from one or more of dimethylformamide, dimethylacetamide, methylpyrrolidone, dimethylsulfoxide, butyrolactone, cyclohexanone, and cyclopentanone;

[0047] The catalyst is selected from tertiary amine catalysts, and the amount of the catalyst added is 20-300% of the amount of substance of the dianhydride compound.

[0048] Preferably, the end capping agent A-M is selected from an amine group-containing end capping agent or an anhydride group-containing end capping agent;

[0049] When the A-M is selected from an amine group-containing end capping agent, at least one of the compounds having the following structures is included:

[0050]

[0051] wherein Z is -O-, -COO-, or -NH-, and R3 is a C1-C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; preferably, R3 is a C4-C10 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; further preferably, the amine group-containing end capping agent includes at least one of the compounds having the following structures:

[0052]

[0053] The molar ratio of the dianhydride compound:(primary alcohol containing R1+ primary alcohol containing R2):diamine compound:amine group-containing end capping agent is 100:(100-105):(94-98):(8-4);

[0054] When the A-M is selected from an anhydride-containing end group controller, at least one of the compounds comprising the following structure is included:

[0055]

[0056] wherein Z is -O-, -COO-, -NH-; R3 is a C1-C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; preferably, R3 is a C4-C10 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; further preferably, the anhydride-containing end group controller includes at least one of the compounds comprising the following structure:

[0057]

[0058] The molar ratio of the dianhydride compound: (primary alcohol containing R1 + primary alcohol containing R2): diamine compound: anhydride-containing end group controller is (94-98):(100-105):100:(8-4);

[0059] The molar ratio of the primary alcohol containing R1 to the primary alcohol containing R2 is 100:(20-60).

[0060] The present application also provides a photoresist, comprising the above low-temperature curing, low-thermal expansion photosensitive polyimide resin.

[0061] Preferably, the photoresist comprises:

[0062] 100 parts by mass of the photosensitive polyimide resin;

[0063] 1-20 parts by mass of the photoinitiator;

[0064] 0-10 parts by mass of the coupling agent;

[0065] 0-10 parts by mass of the polymerization inhibitor;

[0066] 150-400 parts by mass of the solvent.

[0067] Preferably, the photoinitiator is selected from compounds comprising a benzophenone, N-alkylaminoacetophenone, oxime ester, acridine, phosphine oxide, and 2,4,5-triphenyl imidazole structure;

[0068] The coupling agent is selected from silane coupling agents;

[0069] The polymerization inhibitor is selected from free radical polymerization inhibitors.

[0070] The present application also provides a patterning method of the above photoresist, comprising the following steps:

[0071] The photoresist is coated, pre-baked, exposed, developed, and heat-cured to obtain a patterned topography.

[0072] Preferably, the temperature of the heat curing is ≤200℃, the time is 0.5-5 hours, and the atmosphere of the heat curing is selected from air, nitrogen or argon.

[0073] Compared with the prior art, the present application provides a low-temperature curing and low-thermal expansion photosensitive polyimide resin, characterized by having a structure shown in Formula I, wherein X is a residue of a tetracarboxylic dianhydride for polyamide acid ester polymerization; Y at least contains a group of nitrogen-containing aromatic heterocyclic structure; R1 is a group of a polymerizable olefin structure with C4-C20; R2 is a linear or branched alkyl group with C1-C12, or a linear or branched alkyl group containing an ether bond -O-; M at least contains one of an amine group and an anhydride group; and n is a polymerization degree, n = 2-150. The photosensitive polyimide resin provided by the present application simultaneously contains allyl side chains and aliphatic side chains, and the main chain contains a nitrogen-containing aromatic heterocyclic ring, so that low curing temperature, low thermal expansion coefficient, high adhesion to copper substrates, and resolution targets in cyclopentanone development can be achieved at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0074] Figure 1 is a pattern with a photolithographic resolution of 2 μm obtained from Example 1;

[0075] Figure 2 is a pattern with a photolithographic resolution of 3 μm obtained from Example 2. DETAILED DESCRIPTION

[0076] The present application provides a low-temperature curing and low-thermal expansion photosensitive polyimide resin, having a structure shown in Formula I:

[0077]

[0078] In Formula I, X is a residue of a tetracarboxylic dianhydride for polyamide acid ester polymerization;

[0079] Y at least contains a group of nitrogen-containing aromatic heterocyclic structure;

[0080] R1 is a group of a polymerizable olefin structure with C4-C20;

[0081] R2 is a linear or branched alkyl group with C1-C12, or a linear or branched alkyl group containing an ether bond -O-;

[0082] M at least contains one of an amine group and an anhydride group;

[0083] n is a polymerization degree, n = 2-150.

[0084] Specifically, in Formula I, X is a tetravalent organic group, specifically a residue of a tetracarboxylic dianhydride for polyamide acid ester polymerization. In some specific embodiments of the present application, X includes at least one of the following groups:

[0085]

[0086]

[0087] In some preferred embodiments of the present application, to achieve the low thermal expansion coefficient target of the present application, X comprises at least one of the following groups:

[0088]

[0089] In formula I, Y is a divalent organic group, which is the residue of a diamine for polymeric amic acid ester polymerization. In some specific embodiments of the present application, to meet the requirements of low curing temperature and high adhesion to copper substrates, Y comprises at least one group containing a nitrogen-containing aromatic heterocyclic structure, preferably Y comprises at least one of the following groups:

[0090]

[0091] Further preferably, Y comprises at least one of the following groups:

[0092]

[0093]

[0094] In some specific embodiments of the present application, Y further comprises a group not containing a nitrogen-containing heterocyclic structure, which comprises at least one of the following groups:

[0095]

[0096] The molar amount of the group containing a nitrogen-containing aromatic heterocyclic structure accounts for > 60% of the total molar amount of the group Y, for example, it can be 61% to 100%.

[0097] In the present application, side chains R1, R2 are structural moieties of esters. R1 is a C4 to C20 polymerizable olefinic structure group; R1 is preferably a C4 to C10 unsaturated ester structure-containing group, R1 is more preferably a group containing an acrylate structure. R1 further preferably comprises at least one of the following groups:

[0098]

[0099] R2 is a C1 to C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-. R2 is preferably at least one of a C4 to C8 linear or branched alkyl group, a linear or branched alkyl group containing a methoxy group.

[0100] In formula I, M comprises at least one of an amine group and an anhydride group.

[0101] M is selected from one of the following groups:

[0102]

[0103] Z is -O-, -COO-, -NH-;

[0104] R3 is a C1-C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-.

[0105] In the present application, n is the degree of polymerization, n = 2-150, and can be 2, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, or any value between 2 and 150, preferably 5-100.

[0106] When the degree of polymerization n is 2-150, the weight average molecular weight is (0.5-10) x 10 4 ; when n is 5-100, the weight average molecular weight is (1-3) x 10 4 .

[0107] The high dissolution rate of the polyamic acid ester resin in cyclohexanone as a developer does not decrease due to the selection or preference of dianhydride, diamine and end group structure in the polyamic acid ester resin, i.e. a sufficient dissolution rate difference between the exposed area and the non-exposed area after exposure can be formed, and further a negative photoresist pattern is formed. The high dissolution rate is a dissolution rate in cyclohexanone > 0.1 μm / s. The preferred dissolution rate is 0.15-1.0 μm / s. This dissolution rate can be used as a necessary factor for high lithographic resolution. The high lithographic resolution is the formation of < 10 μm patterned topography, preferably < 8 μm pattern.

[0108] To achieve the goal of low curing temperature, low thermal expansion coefficient, high adhesion to copper substrate, and high resolution when developed in cyclopentanone, the photosensitive polyamic acid ester provided in the present application has the following structural characteristics:

[0109] 1) In addition to the amide bond in the main chain, at least one nitrogen-containing aromatic heterocyclic structure is contained, so as to realize the catalysis of the tertiary amine structure based on the nitrogen-containing aromatic heterocyclic ring to the curing process, and further reduce the curing temperature; at the same time, the coordination of the nitrogen-containing aromatic heterocyclic ring with copper can realize high adhesion of copper, can improve the water and oxygen barrier property, and can inhibit the migration of copper ions in application, so as to improve the reliability of the product.

[0110] 2) side chain R1, R2 from two different alcohols. At least one allyl structure, so that the polyacylate has photosensitive properties, can be photocrosslinked to reduce the dissolution rate in the developer, achieving the goal of photolithography; at least one structure containing a fatty chain to improve the dissolution rate of photosensitive polyamic acid ester 001 in cyclopentanone as a developing developer.

[0111] 3) for the goal of low thermal expansion coefficient, the dianhydride, diamine structure of photosensitive polyamic acid ester 001 has more rigid structure, said rigid structure, including rigid benzene, biphenyl, aromatic heterocycle, direct connection structure of benzene and aromatic heterocycle, and said these rigid structures, when linked into the polyimide main chain, adopt symmetrical structure.

[0112] 4) end group A contains at least one structure containing a fatty chain to improve the dissolution rate of photosensitive polyamic acid ester 001 in cyclopentanone as a developing developer.

[0113] The application also provides a preparation method of the above low-temperature curing, low-thermal-expansion photosensitive polyimide resin, comprising the following steps:

[0114] A) mixing dianhydride compounds, R1-containing primary alcohol, R2-containing primary alcohol and catalyst in the presence of solvent to react, to obtain diacid diester reaction liquid;

[0115] B) adding the diacid diester reaction liquid to the activator to react, to obtain the reaction system;

[0116] C) adding diamine compounds and end group control agent A-M to the reaction system to carry out polycondensation reaction, to obtain photosensitive polyimide resin.

[0117] The specific chemical reaction formula is as follows:

[0118]

[0119] Among them, the dianhydride compound has the structure shown in formula II:

[0120]

[0121] The diamine compound has the structure shown in formula III:

[0122] H2N-Y-NH2 formula III.

[0123] The preparation process of the polyacylate of the application is a conventional and well-known two-step preparation method. As the key point, the reaction temperature in the reaction process should be controlled to be < 20 ℃, so as to prevent the formation of by-products to reduce the product yield, such as the formation of crosslinked by-products.

[0124] Specifically, the dianhydride compound, the primary alcohol containing R1, the primary alcohol containing R2, the catalyst, and the solvent are added into a reaction container, and the reaction is carried out at a temperature < 20℃ for 4-24h to obtain a diacid diester.

[0125] The conversion rate of the reaction for preparing the diacid diester obtained by the present application needs to be > 98%, and the conversion rate can be determined by a known method, for example, the conversion rate of the reaction can be determined by NMR, so that the yield of the product is high enough.

[0126] The solvent is a common solvent for polyimide polymerization, which can be selected but is not limited to one or more of dimethylformamide, dimethylacetamide, methylpyrrolidone, dimethyl sulfoxide, butyrolactone, cyclohexanone, and cyclopentanone.

[0127] The catalyst is a tertiary amine catalyst, preferably pyridine, substituted pyridine, quinoline, isoquinoline, triethylamine, dimethylaminopyridine, and imidazole. The amount of the catalyst added is 20-300% of the amount of substance of the dianhydride compound, which can be 20%, 50%, 100%, 120%, 140%, 150%, 160%, 180%, 200%, 250%, 300%, or any value between 20% and 300%, preferably any value between 100% and 200%.

[0128] Next, an activating agent is added to the diacid diester reaction solution to obtain a reaction system. The temperature of the reaction is < 20℃, and the reaction time is 0.5-4h, which can be 0.5, 1, 2, 3, 4, or any value between 0.5 and 4h.

[0129] The activating agent can activate the diacid and can be subjected to polycondensation with diamine. The present application needs to activate the diacid first. The activating agent includes using an amide condensing agent or a method of forming an acid halide from the diacid. The method of using an amide condensing agent includes using carbodiimide and carbonyldiimidazole, preferably dicyclohexylcarbodiimide, diisopropylcarbodiimide, and carbonyldiimidazole. The method of forming an acid halide preferably uses thionyl chloride and phosphorus oxychloride.

[0130] Then, a diamine compound and an end group control agent A-M are added to the reaction system to carry out polycondensation to obtain a photosensitive polyimide resin.

[0131] The temperature of the reaction is < 20℃, and the reaction time is 4-24h, which can be 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, or any value between 4 and 24h.

[0132] The end group control agent A-M is selected from an amine group-containing end group control agent or an anhydride group-containing end group control agent, M contains at least one of an amine group and an anhydride group, and A contains at least one fatty chain structure.

[0133] When the A-M is selected from the amine group-containing end group controller, at least one of the compounds comprising the following structure is included:

[0134]

[0135] wherein Z is -O-, -COO-, -NH-, R3 is a C1-C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; preferably, R3 is a C4-C10 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-.

[0136] Further preferably, the amine group-containing end group controller includes at least one of the compounds comprising the following structure:

[0137]

[0138] When the A-M is selected from the anhydride group-containing end group controller, the molar ratio of the dianhydride compound:(primary alcohol containing R1 + primary alcohol containing R2): diamine compound: anhydride group-containing end group controller is (94-98):(100-105):100:(8-4).

[0139] When the A-M is selected from the anhydride group-containing end group controller, at least one of the compounds comprising the following structure is included:

[0140]

[0141] wherein Z is -O-, -COO-, -NH-; R3 is a C1-C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; preferably, R3 is a C4-C10 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; further preferably, the anhydride group-containing end group controller includes at least one of the compounds comprising the following structure:

[0142]

[0143] When the A-M is selected from the anhydride group-containing end group controller, the molar ratio of the dianhydride compound:(primary alcohol containing R1 + primary alcohol containing R2): diamine compound: anhydride group-containing end group controller is (94-98):(100-105):100:(8-4).

[0144] In the present application, the molar ratio of the primary alcohol containing R1 to the primary alcohol containing R2 is 100:(20-60), which can be 100:20, 100:25, 100:30, 100:35, 100:40, 100:45, 100:50, 100:55, 100:60, or any value between 100:(20-60), preferably any value between 100:(30-50).

[0145] As the selection of the highest molecular weight of the polycondensation polymer, it is preferable that the molar ratio of the dianhydride compound: diamine compound is closest to 1:1.

[0146] After the reaction is completed, the reaction system is added with ethanol to terminate the reaction, and then a large amount of deionized water is added to precipitate the polyamic acid ester. The crude product is separated by filtration. Vacuum drying is performed to obtain the product polyamic acid ester.

[0147] The molecular weight, viscosity, and solubility in cyclopentanone of the obtained polyamic acid ester product are analyzed and tested.

[0148] The present application also provides a photoresist including the low-temperature curing, low-thermal expansion photosensitive polyimide resin described above.

[0149] The photoresist is a composition slurry including the polyimide resin of the present application, and the components thereof further include at least a photoinitiator. An auxiliary component for improving the effect can also be added. As the auxiliary component, a coupling agent, a polymerization inhibitor, a solvent, and the like can be included.

[0150] Specifically, the photoresist includes:

[0151] 100 parts by mass of the photosensitive polyimide resin;

[0152] 1 to 20 parts by mass of the photoinitiator;

[0153] 0 to 10 parts by mass of the coupling agent;

[0154] 0 to 10 parts by mass of the polymerization inhibitor;

[0155] 150 to 400 parts by mass of the solvent.

[0156] The photoresist includes 1 to 20 parts by mass of the photoinitiator, based on 100 parts by mass of the photosensitive polyimide resin, and can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or any value between 1 and 20 parts by mass.

[0157] The photoinitiator is a compound capable of generating a radical under light irradiation, and polymerizing a compound containing an olefin unsaturated group. As the photoinitiator generating a radical under light irradiation, at least one is selected from the group consisting of benzophenone, N-alkylaminoacetophenone, oxime ester, acridine, phosphine oxide, and 2,4,5-triphenyl imidazole structure. As specific examples, benzophenone, N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), 4-methoxy-4'-dimethylaminobenzophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, and 4-benzoyl-4'-methyl diphenyl sulfide; a benzil derivative selected from benzil dimethyl ketal; a benzoin compound selected from benzoin, methyl benzoin, and ethyl benzoin; a benzoin ether compound selected from benzoin methyl ether, benzoin ethyl ether, and benzoin phenyl ether; an oxime ester compound selected from 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime); an N-phenyl glycine derivative selected from N-phenyl glycine; a coumarin compound; a phosphine oxide compound selected from 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

[0158] In the present application, the photoinitiator can be used alone or two or more kinds can be used in combination. Among the above-mentioned photoinitiators, one or more kinds of aromatic ketone, oxime ester compound are more preferable from the viewpoint of improving resolution.

[0159] The photoresist further includes 0 to 10 parts by mass of a coupling agent, based on 100 parts by mass of the photosensitive polyimide resin, which can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between 0 and 10 parts by mass.

[0160] In the present application, the coupling agent is selected from silane coupling agents preferably having a structure represented by the following general formula.

[0161]

[0162] R5 is at least one selected from substituents containing amino, aminoethylamine group, epoxy, phenylamino, ureide, isocyanate. From the viewpoint of improving resolution and improving adhesion of the copper wiring layer, R5 preferably contains at least one of aminoethylamine group, phenylamino, isocyanate substituents.

[0163] R4 is an alkyl group having a carbon number of 1 to 4. Preferably, it is a methyl group, an ethyl group, a propyl group.

[0164] As the silane coupling agent containing an epoxy group, one or more of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane is preferable.

[0165] As the silane coupling agent containing a phenylamino group, N-phenyl-3- aminopropyltrimethoxysilane is preferable.

[0166] As the silane coupling agent containing an aminoethylamine group, N-aminoethyl- 3-aminopropyltrimethoxysilane is preferable.

[0167] As the silane coupling agent containing an isocyanate group, 3- isocyanatopropyltriethoxysilane is preferable.

[0168] The photoresist further includes 0 to 10 parts by mass of a polymerization inhibitor, which can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between 0 and 10 parts by mass, with respect to 100 parts by mass of the photosensitive polyimide resin.

[0169] In the present application, the polymerization inhibitor is selected from radical polymerization inhibitors. The polymerization inhibitor includes a compound containing an aromatic hydroxyl group, a nitroso compound, an N-oxide compound, a quinone compound, an N-oxy radical compound, and a hindered phenol compound.

[0170] As the compound containing an aromatic hydroxyl group, one or more of 4- methoxyphenol, 2,6-di-t-butyl-4-methylphenol, hydroquinone, methylhydroquinone, t- butylhydroquinone, 4,4-thiobis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4- methyl-6-t-butylphenol), a phenol-formaldehyde resin compound, and a cresol resin compound is preferable.

[0171] As the nitroso compound, one or more of nitrosobenzene, 2-nitrosotoluene, 4- nitrosophenol, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 3,5-dibromo-4- nitrosobenzenesulfonic acid, N-nitrosopyrrolidine, and N-nitrosodiphenylamine is preferable.

[0172] As the N-oxide compound, one or more of phenyl-t-butyl nitrone, 5,5-dimethyl- 1-pyrroline-N-oxide, 4-methylmorpholine-N-oxide, pyridine-N-oxide, 4- nitropyridine-N-oxide, and isonicotinic acid-N-oxide is preferable.

[0173] As the quinone compound, one or more of p-benzoquinone, p-dimethylquinone, p- toluquinone, 2,6-dimethyl-1,4-benzoquinone, 2-methylanthraquinone, and 5,12- naphthacenequinone is preferable.

[0174] As the N-oxyl compound, one or more of 2,2,6,6-tetramethylpiperidine 1-oxyl, 4-cyano-2,2,6,6-tetramethylpiperidine 1-oxyl, 4-amino-2,2,6,6-tetramethylpiperidine 1-oxyl is preferred.

[0175] As the hindered phenol compound, one or more of 2,6-di-tert-butyl-4-methylphenol, 2,5-di-tert-butyl-p-benzosequinone, pentaerythritol-tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) is preferred.

[0176] From the photoresist storage stability, resolution, and development residual film rate, the polymerization inhibitor is preferably a compound containing an aromatic hydroxyl group and a nitroso compound, for example, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 4-methoxyphenol, and 2,6-di-tert-butyl-4-methylphenol are preferred. The polymerization inhibitor can be used alone, but at least 2 or more different compounds are preferably used.

[0177] The photoresist further includes 150 to 400 parts by mass of a solvent, which can be 150, 200, 250, 300, 350, 400, or any value between 150 and 400 parts by mass, based on 100 parts by mass of the photosensitive polyimide resin.

[0178] In the present application, the solvent is preferably a polar organic solvent. Further preferred are one or more of N,N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, tetramethyl urea, 1,3-dimethyl-2-imidazolidinone, N-cyclohexyl-2-pyrrolidone, and 3-methoxy-N,N-dimethylpropanamide. The solvent can be used alone or in combination with 2 or more.

[0179] The present application also provides a patterning method of the above photoresist, comprising the following steps:

[0180] The photoresist is coated, pre-baked, exposed, developed, and heat-cured to obtain a patterned topography.

[0181] The specific implementation process includes:

[0182] 1) Coating: The polyimide photoresist solution is coated on the surface of the substrate;

[0183] 2) Pre-baking: The solvent is dried;

[0184] 3) Exposure: The resin layer is irradiated with a mask;

[0185] 4) Development: The resin layer is treated with a developing solution;

[0186] 5) Thermal curing: high temperature heating to pattern formation.

[0187] Specifically:

[0188] 1) Coating: coating of the polyimide photoresist solution on the substrate. The coating method of the present application is a method of coating a photosensitive resin known to those skilled in the art, and can be performed using spin coating, bar coating, blade coating, screen printing, spraying, etc.

[0189] 2) Pre-baking: a drying method known to those skilled in the art, and can be exemplified by methods such as air drying, heating drying based on an oven or a hot plate, vacuum drying, etc. Drying can be performed at 50 to 140°C for 1 minute to 1 hour.

[0190] 3) Exposure: using an exposure device such as a contact photolithography machine, a projection exposure machine, a step-and-repeat exposure machine, etc., with or without a photomask or a grating having a pattern, and using an ultraviolet light source, etc. to expose the dried resin layer.

[0191] Due to the consideration of improving light sensitivity, post-exposure baking (PEB) and / or pre-development baking can also be performed. As for the range of baking conditions, the temperature is preferably 40 to 120°C, and can be 40, 50, 60, 70, 80, 90, 100, 110, 120, or any value between 40 and 120°C, and the time is preferably 10 to 240 seconds.

[0192] 4) Development: developing and removing the unexposed part of the exposed photosensitive resin layer. As a method of developing the exposed resin layer, the known developing methods of photoresists, such as a spin-spray method, an immersion method with ultrasonic treatment, etc. can be exemplified.

[0193] As a developing solution used in development, the present application will preferably use cyclopentanone to adapt to most of the current application scenarios and better environmental requirements.

[0194] 5) Thermal curing: imidization of the polyamide acid ester described in the present application by heating, thereby converting it into a polyimide, and forming a cured pattern. At the same time, the photosensitive component in the system is degraded and volatilized by heating. As a method of thermal curing, it can be a method based on a hot plate, a method using an oven, a method using a temperature-programmable oven, etc.

[0195] The maximum temperature of the curing heating of the present application is <200°C, preferably 150 to 180°C, and is performed under the condition of 30 minutes to 5 hours. The atmosphere gas during heating and curing can be air, or a non-reactive gas such as nitrogen, argon, etc.

[0196] The linear thermal expansion coefficient of the patterned film layer is between 5-20 ppm / K, the modulus reaches 4.0 GPa or more, the elongation at break is >50%, and the tensile strength is >200 MPa, which embodies the characteristics of low curing temperature, high mechanical properties, and low thermal expansion coefficient.

[0197] In order to further understand the present application, the low-temperature curing, low-thermal expansion photosensitive polyimide resin and photoresist provided by the present application are described below in combination with examples, and the protection scope of the present application is not limited by the following examples.

[0198] Example 1

[0199] Nitrogen was introduced into the reaction container at room temperature, 0.13 mol of 4,4-oxydibenzoic dianhydride (PMDA) and 0.1 mol of hydroxyethyl methacrylate, 0.03 mol of ethylene glycol monomethyl ether, and 0.26 mol of pyridine were dissolved in 100 g of N,N-dimethylformamide (DMF) solvent with constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 4 h until all the solvents were dissolved; 0.26 mol of dicyclohexyl carbodiimide (DCC) was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 2 h; 0.122 mol of 2,5-bis(4-aminophenyl)pyridine (PRD) and 0.0104 mol of p-aminophenyl ether were continuously 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, and the reaction product was poured into anhydrous ethanol for precipitation; finally, the product was filtered and dried to obtain a photosensitive polyimide resin.

[0200] 2 g of photosensitive polyimide resin, 0.04 g of benzophenone, 0.04 g of 2-(3,4-epoxy cyclohexyl) ethyl trimethoxysilane, 0.04 g of 2,6-di-tert-butyl-p-methyl phenol, and 3.0 g of N-methyl-2-pyrrolidone (NMP) were stirred and mixed uniformly to obtain a negative photosensitive polyimide composition.

[0201] Example 2

[0202] A reaction vessel was purged with nitrogen at room temperature, 0.1386 mol of 3,3',4,4'-biphenyl tetracarboxylic dianhydride (BPDA) and 0.1 mol of hydroxyethyl methacrylate, 0.04 mol of ethylene glycol monoethyl ether, 0.277 mol of quinoline were dissolved in 100 g of N,N-dimethylacetamide (DMAc) solvent with constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 6 h until complete dissolution; 0.277 mol of DCC was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 4 h; 0.079 mol of PRD, 0.053 mol of 4,4'-diamino diphenyl ether (ODA), and 0.0111 mol of p-aminophenyl methyl ether were continuously added, and the polycondensation reaction was continuously carried out for 10 h; after the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction, and the reaction product was poured into anhydrous ethanol for precipitation; and finally, the product was filtered and dried to obtain a photosensitive polyimide resin.

[0203] 2 g of the photosensitive polyimide resin, 0.1 g of N-alkylaminoacetophenone, 0.06 g of N-phenyl-3-aminopropyl trimethoxysilane, 0.06 g of 4-methoxyphenol, and 4.0 g of DMF were uniformly mixed with stirring to obtain a negative photosensitive polyimide composition.

[0204] Example 3

[0205] A reaction vessel was purged with nitrogen at room temperature, 0.147 mol of 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) and 0.1 mol of hydroxyethyl methacrylate, 0.05 mol of ethylene glycol monomethyl ether, and 0.294 mol of triethylamine were dissolved in 100 g of γ-butyrolactone solvent with constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 8 h until complete dissolution; 0.294 mol of DCC was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 3 h; 0.099 mol of 2,5-bis(4-aminophenyl)pyrimidine (PRM), 0.042 mol of 4,4'-diamino-2,2'-dimethyl-1,1'-biphenyl (mTB), and 0.0088 mol of p-aminobenzoic acid were continuously added, and the polycondensation reaction was continuously carried out for 15 h; after the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction, and the reaction product was poured into anhydrous ethanol for precipitation; and finally, the product was filtered and dried to obtain a photosensitive polyimide resin.

[0206] 2 g of the photosensitive polyimide resin, 0.2 g of N,N,N',N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), 0.1 g of N-aminoethyl-3-aminopropyl trimethoxysilane, 0.1 g of p-aminophenol, and 5.0 g of DMAc were uniformly mixed with stirring to obtain a negative photosensitive polyimide composition.

[0207] Example 4

[0208] A reaction vessel was purged with nitrogen at room temperature, 0.125 mol of 1,3-dioxo-1,3-dihydroisobenzofuran-5-yl 1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate (JFCA) and 0.1 mol of hydroxyethyl methacrylate, 0.03 mol of ethylene glycol monomethyl ether, and 0.25 mol of dimethylamino pyridine were dissolved in 100 g of dimethyl sulfoxide (DMSO) solvent with constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was allowed to proceed for 10 h until complete dissolution. 0.25 mol of DCC was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was allowed to proceed for 2 h. 0.097 mol of 2-(4-aminophenyl)-5-aminobenzoxazole (BOA), 0.024 mol of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (TFDB), and 0.0063 mol of methyl p-aminobenzoate were further added, and the polycondensation reaction was allowed to proceed 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 poured into anhydrous ethanol to precipitate, and finally, the product was filtered and dried to obtain a photosensitive polyimide resin.

[0209] 2 g of the photosensitive polyimide resin, 0.3 g of 4-methoxy-4'-dimethylaminobenzophenone, 0.16 g of 3-isocyanatepropyl triethoxysilane, 0.16 g of methyl hydroquinone, and 6.0 g of cyclopentanone were stirred and mixed uniformly to obtain a negative photosensitive polyimide composition.

[0210] Example 5

[0211] A reaction vessel was purged with nitrogen at room temperature, 0.133 mol of bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid) 1,4-phenylene ester (ESDA) and 0.1 mol of hydroxyethyl methacrylate, 0.04 mol of ethylene glycol monoethyl ether, and 0.266 mol of imidazole were dissolved in 100 g of DMAc solvent with constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was allowed to proceed for 12 h until complete dissolution. 0.266 mol of DCC was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was allowed to proceed for 3 h. 0.1176 mol of 2-(4-aminophenyl)-5-aminobenzimidazole (APBIA), 0.0131 mol of ODA, and 0.0053 mol of p-aminobenzoic acid were further added, and the polycondensation reaction was allowed to proceed 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 poured into anhydrous ethanol to precipitate, and finally, the product was filtered and dried to obtain a photosensitive polyimide resin.

[0212] Take 2g photosensitive polyimide resin, 0.4g 1,2-octane dione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], 0.2g 2-(3,4-epoxy cyclohexyl) ethyl trimethoxysilane, 0.2g tert-butyl hydroquinone, 8.0g DMF, stirring and mixing uniformly, to obtain a negative photosensitive polyimide composition.

[0213] Example 6

[0214] The reaction vessel is purged with nitrogen at room temperature, 0.141 mol PMDA and 0.1 mol hydroxyethyl methacrylate, 0.05 mol ethylene glycol monomethyl ether, 0.28 mol pyridine are dissolved in 100 g NMP solvent, stirring constantly, the reaction temperature is reduced to 20℃, and the reaction is carried out for 14h until all the solvents are dissolved; 0.28 mol DCC is added to the transparent solution, the reaction temperature is controlled at 20℃, and the activation reaction is carried out for 4h; 0.15 mol PRD and 0.012 mol 5-methoxy-isobenzofuran-1,3-dione are continuously added, and the polycondensation reaction is continued for 24h; after the temperature returns to room temperature, ethanol is added to the reaction system to terminate the reaction, and the reaction product is poured into anhydrous ethanol for precipitation, and finally filtered and dried to obtain a photosensitive polyimide resin.

[0215] Take 2g photosensitive polyimide resin, 0.04g benzophenone, 0.04g 2-(3,4-epoxy cyclohexyl) ethyl trimethoxysilane, 0.04g 2,6-di-tert-butyl-p-methyl phenol, 3.0g γ-butyrolactone, stirring and mixing uniformly, to obtain a negative photosensitive polyimide composition.

[0216] Example 7

[0217] The reaction vessel is purged with nitrogen at room temperature, 0.1223 mol BPDA and 0.1 mol hydroxyethyl methacrylate, 0.03 mol ethylene glycol monomethyl ether, 0.244 mol pyridine are dissolved in 100 g γ-butyrolactone solvent, stirring constantly, the reaction temperature is reduced to 20℃, and the reaction is carried out for 16h until all the solvents are dissolved; 0.244 mol DCC is added to the transparent solution, the reaction temperature is controlled at 20℃, and the activation reaction is carried out for 2h; 0.077 mol PRD, 0.051 mol ODA and 0.0103 mol 1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylic acid methyl ester are continuously added, and the polycondensation reaction is continued for 24h; after the temperature returns to room temperature, ethanol is added to the reaction system to terminate the reaction, and the reaction product is poured into anhydrous ethanol for precipitation, and finally filtered and dried to obtain a photosensitive polyimide resin.

[0218] Take 2 g of photosensitive polyimide resin, 0.1 g of N-alkylaminoacetophenone, 0.06 g of N-phenyl-3-aminopropyl trimethoxysilane, 0.06 g of 4-methoxyphenol, 4.0 g of DMSO, stir and mix uniformly to obtain a negative photosensitive polyimide composition.

[0219] Example 8

[0220] Nitrogen was introduced into the reaction container at room temperature, 0.132 mol of BTDA and 0.1 mol of hydroxyethyl methacrylate, 0.04 mol of ethylene glycol monomethyl ether, 0.26 mol of pyridine were dissolved in 100 g of DMF solvent, and the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 16 h until all the solvents were dissolved; 0.26 mol of DCC was added to the transparent solution, and the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 3 h; 0.096 mol of PRM, 0.041 mol of mTB and 0.0082 mol of 5-methoxy-isobenzofuran-1,3-dione were continuously added, and the polycondensation reaction was continued for 4 h; after the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction, and then the reaction product was poured into anhydrous ethanol for precipitation, and finally filtered and dried to obtain a photosensitive polyimide resin.

[0221] Take 2 g of photosensitive polyimide resin, 0.1 g of N-alkylaminoacetophenone, 0.06 g of N-phenyl-3-aminopropyl trimethoxysilane, 0.06 g of 4-methoxyphenol, 4.0 g of DMSO, stir and mix uniformly to obtain a negative photosensitive polyimide composition

[0222] Example 9

[0223] Nitrogen was introduced into the reaction container at room temperature, 0.132 mol of BTDA and 0.1 mol of hydroxyethyl methacrylate, 0.04 mol of ethylene glycol monomethyl ether, 0.26 mol of pyridine were dissolved in 100 g of DMF solvent, and the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 16 h until all the solvents were dissolved; 0.26 mol of DCC was added to the transparent solution, and the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 3 h; 0.096 mol of PRM, 0.041 mol of mTB and 0.0082 mol of 5-methoxy-isobenzofuran-1,3-dione were continuously added, and the polycondensation reaction was continued for 4 h; after the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction, and then the reaction product was poured into anhydrous ethanol for precipitation, and finally filtered and dried to obtain a photosensitive polyimide resin.

[0224] Take 2 g of photosensitive polyimide resin, 0.3 g of 4-methoxy-4'-dimethylaminobenzophenone, 0.16 g of 3-isocyanate propyl triethoxysilane, 0.16 g of methyl hydroquinone, 6.0 g of cyclopentanone, stir and mix evenly to get a negative photosensitive polyimide composition.

[0225] Example 10

[0226] Under nitrogen, 0.12 mol of ESDA and 0.1 mol of hydroxyethyl methacrylate, 0.03 mol of ethylene glycol monomethyl ether, and 0.24 mol of pyridine were dissolved in 100 g of NMP solvent under constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 18 h until complete dissolution; 0.24 mol of DCC was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 2 h; 0.111 mol of APBIA, 0.012 mol of ODA, and 0.0050 mol of 5-methoxy-iso-benzofuran-1,3-dione were continuously added, and the polycondensation reaction was continued for 10 h; after the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction, and then the reaction product was poured into anhydrous ethanol for precipitation, and finally dried by filtration to obtain a photosensitive polyimide resin.

[0227] Take 2 g of photosensitive polyimide resin, 0.3 g of 4-methoxy-4'-dimethylaminobenzophenone, 0.16 g of 3-isocyanate propyl triethoxysilane, 0.16 g of methyl hydroquinone, 6.0 g of cyclopentanone, stir and mix evenly to get a negative photosensitive polyimide composition.

[0228] Comparative Example 1

[0229] Under nitrogen, 0.12 mol of ESDA and 0.1 mol of hydroxyethyl methacrylate, 0.03 mol of ethylene glycol monomethyl ether, and 0.24 mol of pyridine were dissolved in 100 g of NMP solvent under constant stirring, the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 18 h until complete dissolution; 0.24 mol of DCC was added to the transparent solution, the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 2 h; 0.111 mol of APBIA, 0.012 mol of ODA, and 0.0050 mol of 5-methoxy-iso-benzofuran-1,3-dione were continuously added, and the polycondensation reaction was continued for 10 h; after the temperature returned to room temperature, ethanol was added to the reaction system to terminate the reaction, and then the reaction product was poured into anhydrous ethanol for precipitation, and finally dried by filtration to obtain a photosensitive polyimide resin.

[0230] Take 2 g of photosensitive polyimide resin, 0.04 g of benzophenone, 0.04 g of 2-(3,4-epoxy cyclohexyl) ethyl trimethoxysilane, 0.04 g of 2,6-di-tert-butyl-p-cresol, 3.0 g of NMP, stir and mix uniformly to obtain a negative photosensitive polyimide composition.

[0231] Comparative Example 2

[0232] Into a reaction vessel, 0.13 mol of PMDA and 0.13 mol of hydroxyethyl methacrylate, 0.26 mol of pyridine were dissolved in 100 g of DMF solvent under constant stirring, and the reaction temperature was reduced to the range of 20°C, and the reaction was carried out for 4 h until all the solute was dissolved; 0.26 mol of DCC was added to the transparent solution, and the reaction temperature was controlled in the range of 20°C, and the activation reaction was carried out for 2 h; 0.13 mol of PRD was continuously 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, and the reaction product was poured into anhydrous ethanol for precipitation, and finally filtered and dried to obtain a photosensitive polyimide resin.

[0233] Take 2 g of photosensitive polyimide resin, 0.04 g of benzophenone, 0.04 g of 2-(3,4-epoxy cyclohexyl) ethyl trimethoxysilane, 0.04 g of 2,6-di-tert-butyl-p-cresol, 3.0 g of NMP, stir and mix uniformly to obtain a negative photosensitive polyimide composition.

[0234] Performance test

[0235] 1. Performance test of photosensitive polyimide resin

[0236] The molecular weight, viscosity and dissolution rate in cyclopentanone of the obtained polyamide acid ester resin product were analyzed and tested.

[0237] 2. Performance test of photosensitive polyimide composition

[0238] The polyimide photoresist solution can form a patterned topography through the processes of coating, pre-baking, exposure, development, and thermal curing.

[0239] 1) Coating: The polyimide photoresist solution was spin-coated on a silicon substrate.

[0240] 2) Pre-baking: The silicon wafer was dried on a hot plate at 100°C for 10 minutes.

[0241] 3) Exposure: A projection exposure machine was used, a photo mask with a pattern was used, and the dried resin layer was exposed to ultraviolet light source. The post-exposure baking (PEB) conditions were temperature 70°C and time 120 seconds.

[0242] 4) Development: Cyclopentanone was used as the developing solution, and the development was carried out by the rotary spray method.

[0243] 5) Thermal curing: using oven, the pattern is heat imidized by step temperature, 100℃ for 1 hour, 200℃ for 1 hour, the rate of temperature rising is 10℃ / min.

[0244] Then cool to room temperature, the pattern is peeled off from the substrate, the resolution of the film is observed by ESEM XL-30 field emission environmental scanning electron microscope.

[0245] Imidization rate: the 10μm PSPI film prepared after patterning is tested by Fourier infrared spectrometer, the ratio of the characteristic peak of 1380cm -1 C-N stretching vibration and 1500cm -1 ring stretching vibration of the sample is taken, and the PSPI treated at 350℃ for 1h is taken as 100% imidization sample, the imidization rate of each PSPI sample is calculated.

[0246] Thermal expansion coefficient: the 10μm PSPI film prepared after patterning is tested by TMA company's Q400 thermal mechanical analyzer in air, the rate of temperature rising is 3℃ / min, the temperature range is 25-300℃.

[0247] Mechanical properties: the 10μm PSPI film prepared after patterning is tested by INSTRON-1121 universal testing machine of Instron company, the tensile strength (σm), tensile modulus (Et) and elongation at break (εb) of the polyimide film are tested, the tensile rate is 5mm / min.

[0248] The test results of the photosensitive polyimide resin of each example 1-10 and comparative example 1, 2 are shown in Table 1:

[0249] Table 1

[0250]

[0251]

[0252] The test results of the photosensitive polyimide composition of each example 1-10 and comparative example 1, 2 are shown in Table 2, 3:

[0253] Table 2

[0254]

[0255]

[0256] Table 3

[0257] Tensile strength (MPa) Elastic modulus (GPa) Elongation at break (%) Example 1 213 5.8 51 Example 2 236 4.2 73 Example 3 225 4.4 68 Example 4 237 4.7 62 Example 5 216 5.3 54 Example 6 252 6.1 52 Example 7 248 4.3 67 Example 8 229 4.7 61 Example 9 243 5.2 56 Example 10 221 5.5 52 Comparative Example 1 242 2.9 83 Comparative Example 2 236 5.8 54

[0258] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0259] By introducing the tertiary amine structure of nitrogen-containing aromatic heterocycle into the polyimide macromolecular chain, due to the catalytic effect, the curing temperature of the film is completely imidized at below 200℃; the structure containing a fatty chain is introduced into the side chain, which improves the dissolution speed of the photosensitive polyamic acid ester in cyclopentanone; the rigid structure is introduced into the main chain structure, so that the PSPI film has a lower thermal expansion coefficient: 5-20 ppm K -1 , with the increase of the amount of the rigid diamine, the thermal expansion coefficient is lower and the elastic modulus is larger. The end group is introduced into the end-capping agent containing a fatty chain, the molecular weight is controlled, the dissolution speed of the polyamic acid ester resin and the polyamic acid film in cyclopentanone is increased, and a higher photoetching resolution ≤5 μm is obtained. Referring to Figure 1 and Figure 2 , Figure 1 is a pattern with a photoetching resolution of 2 μm obtained from example 1; Figure 2 is a pattern with a photoetching resolution of 3 μm obtained from example 2.

[0260] The above-mentioned is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A low-temperature-curing, low-heat-expansion photosensitive polyimide resin, characterized by, having the structure of Formula I: In Formula I, X is a residue of a tetracarboxylic dianhydride polymerized with a polyamic acid ester; Y comprises at least a group containing a nitrogen-containing aromatic heterocyclic structure; R1 is a group of a polymerizable olefin structure of C4-C20; R2 is a linear or branched alkyl group of C1-C12, or a linear or branched alkyl group containing an ether bond -O-; M comprises at least one of an amine group and an anhydride group; n is a degree of polymerization, n = 2-150.

2. The photosensitive polyimide resin according to claim 1, characterized by X comprises at least one of the following groups:

3. The photosensitive polyimide resin according to claim 1, wherein X comprises at least one of the following groups:

4. The photosensitive polyimide resin according to claim 1, wherein Y comprises at least one of the following groups:

5. The photosensitive polyimide resin according to claim 1, wherein Y comprises at least one of the following groups:

6. The photosensitive polyimide resin according to claim 4, wherein Y further comprises a group not containing a nitrogen-containing heterocyclic structure, which comprises at least one of the following groups: The molar amount of the group containing a nitrogen-containing aromatic heterocyclic structure accounts for >60% of the total molar amount of the group Y.

7. The photosensitive polyimide resin according to claim 1, wherein R1 comprises at least one of the following groups: R2 is selected from at least one of a linear or branched alkyl group of C4-C8, a linear or branched alkyl group containing a methoxy group.

8. The photosensitive polyimide resin according to claim 1, wherein M comprises at least one of an amine group and an anhydride group, and M is selected from one of the following groups: Z is -O-, -COO-, -NH-; R3 is a linear or branched alkyl group of C1-C12, or a linear or branched alkyl group containing an ether bond -O-.

9. The photosensitive polyimide resin according to claim 1, wherein The weight average molecular weight of the photosensitive polyimide resin is (0.5-10) x 10 4 .

10. A process for producing a low-temperature-curable, low-heat-expansion photosensitive polyimide resin as claimed in any one of claims 1 to 9, characterized by, comprising the following steps: A) mixing a dianhydride compound, a primary alcohol containing R1, a primary alcohol containing R2, a catalyst in the presence of a solvent to react, to obtain a diacid diester reaction solution; B) adding an activating agent to the diacid diester reaction solution to react, to obtain a reaction system; C) adding a diamine compound and an end group control agent A-M to the reaction system to carry out a polycondensation reaction, to obtain a photosensitive polyimide resin.

11. The method of claim 10, wherein, In step A), the temperature of the reaction is <20°C, and the reaction time is 4-24 h; In step B), the temperature of the reaction is <20°C, and the reaction time is 0.5-4 h; In step C), the temperature of the reaction is <20°C, and the reaction time is 4-24 h; The solvent is selected from one or more of dimethylformamide, dimethylacetamide, methylpyrrolidone, dimethyl sulfoxide, butyrolactone, cyclohexanone, cyclopentanone; The catalyst is selected from a tertiary amine catalyst, and the amount of the catalyst added is 20-300% of the amount of substance of the dianhydride compound.

12. The method of claim 10, wherein, The end group control agent A-M is selected from an amine group-containing end group control agent or an anhydride group-containing end group control agent; When the A-M is selected from an amine group-containing end group control agent, it comprises at least one of the following compounds having the structure: wherein Z is -O-, -COO-, -NH-, and R3 is a linear or branched alkyl group of C1-C12, or a linear or branched alkyl group containing an ether bond -O-; preferably, R3 is a linear or branched alkyl group of C4-C10, or a linear or branched alkyl group containing an ether bond -O-; further preferably, the amine group-containing end group control agent comprises at least one of the following compounds having the structure: The molar ratio of the dianhydride compound: (primary alcohol containing R1 + primary alcohol containing R2): diamine compound: amine group-containing end group control agent is 100: (100-105): (94-98): (8-4). When the A-M is selected from an anhydride group-containing end group controller, at least one of the compounds comprising the following structure is included: wherein Z is -O-, -COO-, -NH-; R3 is a C1-C12 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; preferably, R3 is a C4-C10 linear or branched alkyl group, or a linear or branched alkyl group containing an ether bond -O-; further preferably, the anhydride group-containing end group controller comprises at least one of the compounds comprising the following structure: The molar ratio of the dihydric anhydride compound: (primary alcohol containing R1 + primary alcohol containing R2): diamine compound: anhydride group-containing end group controller is (94-98):(100-105):100:(8-4); The molar ratio of the primary alcohol containing R1 to the primary alcohol containing R2 is 100:(20-60).

13. A photoresist, characterized by, The low-temperature curing, low-thermal expansion photosensitive polyimide resin according to any one of claims 1-9.

14. The photoresist of claim 13, wherein Comprises: 100 parts by mass of a photosensitive polyimide resin; 1-20 parts by mass of a photoinitiator; 0-10 parts by mass of a coupling agent; 0-10 parts by mass of a polymerization inhibitor; 150-400 parts by mass of a solvent.

15. The photoresist of claim 14, wherein The photoinitiator is selected from compounds comprising a benzophenone, an N-alkyl aminoacetophenone, an oxime ester, an acridine, a phosphine oxide, and a 2,4,5-triphenyl imidazole structure; The coupling agent is selected from a silane coupling agent; The polymerization inhibitor is selected from a free radical polymerization inhibitor.

16. A method of patterning a photoresist according to any one of claims 13 to 15, characterized in that, Comprises the following steps: The photoresist is coated, pre-baked, exposed, developed, and heat-cured to obtain a patterned topography.

17. The method of claim 16, wherein The temperature of the heat curing is ≤200°C, and the time is 0.5-5 hours, and the atmosphere of the heat curing is selected from air, nitrogen, or argon.

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