CN121005901A

CN121005901A - Low-temperature curing, low-thermal-expansion photosensitive polyimide resin and its photoresist

Info

Publication number: CN121005901A
Application number: CN202511123197.2A
Authority: CN
Inventors: 马姣姣; 时舜; 李泽宇; 张春华; 郭海泉
Original assignee: Changchun Institute of Applied Chemistry of CAS
Current assignee: Changchun Institute of Applied Chemistry of CAS
Priority date: 2025-08-12
Filing date: 2025-08-12
Publication date: 2025-11-25

Abstract

本发明提供了低温固化、低热膨胀光敏聚酰亚胺树脂，其特征在于，具有式I所示结构，式I中，X为聚酰胺酸酯聚合的四羧酸二酐的残基；Y至少包含含氮芳杂环结构的基团；R₁为C4～C20的可聚合烯烃结构的基团；R₂为C1～C12的直链或支链烷烃基，或含有醚键‑O‑的直链或支链烷烃基；M至少包含胺基、酐基中的一种；n为聚合度，n＝2～150。本发明提供的光敏聚酰亚胺树脂同时含有烯丙基侧链、脂肪侧链，主链含有含氮芳杂环，可以同时达到低固化温度、低热膨胀系数、与铜基材的高附着力、且在环戊酮显影的分辨率目标。This invention provides a low-temperature curing, low-thermal-expansion photosensitive polyimide resin, characterized by having the structure shown in Formula I, where X is a residue of a tetracarboxylic acid dianhydride polymerized from a polyamide ester; Y contains at least a nitrogen-containing aromatic heterocyclic group; _R1 is a C4-C20 polymerizable olefin group; _R2 is a C1-C12 straight-chain or branched alkane group, or a straight-chain or branched alkane group containing an ether bond -O-; M contains at least one of an amine group or an anhydride group; and n is the degree of polymerization, n = 2-150. The photosensitive polyimide resin provided by this invention simultaneously contains allyl side chains and aliphatic side chains, and the main chain contains a nitrogen-containing aromatic heterocyclic ring, thus simultaneously achieving the goals of low curing temperature, low coefficient of thermal expansion, high adhesion to copper substrates, and high resolution in cyclopentanone development.

Description

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

Technical Field

The invention belongs to the technical field of polyimide, and particularly relates to a low-temperature curing and low-thermal expansion photosensitive polyimide resin and photoresist thereof.

Background

Polyimide has excellent heat resistance, insulation and chemical resistance. Is widely used as an insulating material for electronic devices, and as a passivation film, a surface protective film, an interlayer insulating film, etc. for semiconductor devices. Photosensitive polyimide imparting photosensitivity to polyimide, and a photoresist composition containing an auxiliary agent such as photosensitive polyimide and a photosensitive agent. Patterning of polyimide can be achieved through coating, exposure, development, and thermal curing (imidization) process based on curing. By using a photosensitive polyimide, a process can be easily shortened significantly as compared with the case of using a non-photosensitive polyimide.

In recent years, with miniaturization and higher performance of various electronic devices such as personal computers, digital cameras, and mobile phones, demands for further miniaturization, thinning, and higher density of semiconductor devices have been rapidly increasing. Therefore, the semiconductor package structure is changing from the viewpoint of improving the integration level and the arithmetic function. Rapid developments are being made in high density mounting techniques such as chip scale packages or three dimensional stacks of chip scale packages. In such advanced packaging technology, the application of photosensitive polyimide capable of forming a pattern on a substrate as a protective film, an insulating layer, a dielectric layer, the insulation property, mechanical strength, thermal expansion property, bonding force of the substrate, and the like have been attracting attention.

Conventionally, a photosensitive polyimide material has been produced by using a polyamic acid derivative which is a polyimide precursor, for example, by introducing a photosensitive group into a carboxyl group of a polyamic acid through an ester bond. However, after patterning, imidization treatment is performed at a high temperature exceeding 300 ℃ in order to obtain the objective polyimide. This high temperature may affect the base substrate or may oxidize copper of the wiring. Therefore, there is a demand for lowering the curing temperature.

The photosensitive polyimide is applied as an insulating layer and a dielectric layer, and is subjected to a temperature of about 260 ℃ in a soldering reflow soldering process in a semiconductor manufacturing process. The reflow process is in contact with the wafer substrate and copper wiring, and large stresses are generated between the photosensitive polyimide layer and the copper sheet due to thermal expansion mismatch in the multi-layer stacked package. There is a problem that the adhesion is insufficient and a problem such as delamination occurs. Thus, there is a need to reduce the coefficient of thermal expansion of photosensitive polyimide, and to increase adhesion to copper, as well as to inhibit migration of copper ions.

Therefore, with the development of high density and high integration of chips, the miniaturization of polyimide as an insulating dielectric layer for RDL re-wiring technology should be advanced, and at the same time, a curing temperature lower than 200 degrees is required, and a low thermal expansion coefficient is still maintained, and sufficient mechanical strength and adhesion to copper are provided.

Meanwhile, the low-temperature curing is selected for the developing solvent, and the boiling point requirement lower than the curing temperature and the environment-friendly requirement are considered. When using low temperature curing, the use of industry conventional cyclohexanone as a developer is encouraged, rather than development with N-methyl-2-pyrrolidone (NMP) for low temperature curing, which is listed in SVHC (permissible target candidate) in the REACH rule of europe. For these reasons, N-methyl-2-pyrrolidone is a solvent which is as avoided as possible.

Therefore, it is a problem to be solved to provide a photoresist that achieves both low curing temperature, low thermal expansion coefficient, high adhesion to copper substrates, and still has high resolution effect upon cyclopentanone development.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a low-temperature cured low-thermal expansion photosensitive polyimide resin and a photoresist thereof, wherein the photoresist provided by the present invention can achieve the effects of low curing temperature, low thermal expansion coefficient, high adhesion with copper substrate, and high resolution during cyclopentanone development.

The invention provides a low-temperature curing and low-thermal expansion photosensitive polyimide resin, which has a structure shown in a formula I:

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

y comprises at least a group containing a nitrogen-containing aromatic heterocyclic structure;

R ₁ is a group of a polymerizable olefin structure of C4-C20;

R ₂ is C1-C12 straight-chain or branched-chain alkyl or straight-chain or branched-chain alkyl containing ether bond-O-;

m at least comprises one of an amine group and an anhydride group;

n is the degree of polymerization, n=2 to 150.

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

preferably, X comprises at least one of the following groups:

preferably, Y comprises at least one of the following groups:

Preferably, Y further comprises a nitrogen-free heterocyclic structure group comprising at least one of the following groups:

the molar amount of the nitrogen-containing aromatic heterocyclic structure groups is >60% of the total molar amount of the groups Y.

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

r2 is at least one of C4-C8 straight-chain or branched-chain alkyl and methoxy-containing straight-chain or branched-chain alkyl.

Preferably, 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-;

R ₃ is C1-C12 straight-chain or branched-chain alkyl or straight-chain or branched-chain alkyl containing ether bond-O-.

Preferably, the weight average molecular weight of the photosensitive polyimide resin is (0.5-10) ×10 ⁴.

The invention also provides a preparation method of the low-temperature curing and low-thermal expansion photosensitive polyimide resin, which comprises the following steps:

a) Mixing dianhydride compounds, primary alcohol containing R1, primary alcohol containing R2 and a catalyst for reaction in the presence of a solvent to obtain diacid diester reaction liquid;

B) Adding an activating agent into the diacid diester reaction liquid to react, so as to obtain a reaction system;

c) And adding a diamine compound and an end group control agent A-M into the reaction system to perform polycondensation reaction to obtain the photosensitive polyimide resin.

Preferably, in the step A), the reaction temperature is less than 20 ℃, and the reaction time is 4-24 hours;

In the step B), the reaction temperature is less than 20 ℃, and the reaction time is 0.5-4 h;

in the step C), the reaction temperature is less than 20 ℃, and the reaction time is 4-24 hours;

the solvent is one or more selected from dimethylformamide, dimethylacetamide, methylpyrrolidone, dimethyl sulfoxide, butyrolactone, cyclohexanone and cyclopentanone;

the catalyst is selected from tertiary amine catalysts, and the addition amount of the catalyst is 20-300% of the amount of the dianhydride compound.

Preferably, the end control agent A-M is selected from amine group-containing end control agents or anhydride group-containing end control agents;

When the a-M is selected from amine-containing end-group control agents, at least one of the following compounds is included:

Wherein Z is-O-, -COO-, -NH-, and R ₃ is C1-C12 straight-chain or branched-chain alkyl or straight-chain or branched-chain alkyl containing ether bond-O-; preferably, R ₃ is a C4-C10 linear or branched alkyl group or a linear or branched alkyl group containing an ether bond-O-, and further preferably, the amine group-containing end group control agent comprises at least one of the following compounds:

The molar ratio of the dianhydride compound (primary alcohol containing R ₁ and primary alcohol containing R ₂) to the diamine compound to the amine group-containing end group control agent is 100 to 105 to 94 to 98 to 8~4;

When the a-M is selected from anhydride group-containing end-control agents, at least one of the compounds comprising the structure:

Wherein Z is-O-, -COO-, -NH-, R ₃ is a C1-C12 linear or branched alkyl group or a linear or branched alkyl group containing an ether bond-O-, preferably R ₃ is a C4-C10 linear or branched alkyl group or a linear or branched alkyl group containing an ether bond-O-, further preferably the end group control agent containing an anhydride group comprises at least one of the following compounds:

The molar ratio of the dianhydride compound (primary alcohol containing R ₁ and primary alcohol containing R ₂) to the diamine compound to the end group control agent containing anhydride group is (94-98): (100-105): (8~4);

the molar ratio of the primary alcohol containing R ₁ to the primary alcohol containing R ₂ is 100 (20-60).

The invention also provides a photoresist, which comprises the low-temperature curing and low-thermal expansion photosensitive polyimide resin.

Preferably, the photoresist includes:

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.

Preferably, the photoinitiator is selected from the group consisting of compounds comprising benzophenone, N-alkylaminoacetophenone, oxime esters, acridine, phosphine oxide, and 2,4, 5-triphenylimidazole structures;

the coupling agent is selected from silane coupling agents;

the polymerization inhibitor is selected from radical polymerization inhibitors.

The invention also provides a patterning method of the photoresist, which comprises the following steps:

and coating, prebaking, exposing, developing and thermally curing the photoresist to obtain the patterned morphology.

Preferably, the temperature of the thermal curing is less than or equal to 200 ℃ and the time is 0.5-5 hours, and the atmosphere of the thermal curing is selected from air, nitrogen or argon.

Compared with the prior art, the invention provides a low-temperature curing and low-thermal expansion photosensitive polyimide resin which is characterized by having a structure shown in a formula I, wherein X is a residue of tetracarboxylic dianhydride polymerized by polyamide acid ester, Y at least comprises a group with a nitrogen-containing aromatic heterocyclic ring structure, R ₁ is a group with a polymerizable olefin structure of C4-C20, R ₂ is a linear or branched alkane group of C1-C12 or a linear or branched alkane group containing ether bond-O-, M at least comprises one of an amino group and an anhydride group, and n is the degree of polymerization, wherein n=2-150. The photosensitive polyimide resin provided by the invention contains an allyl side chain and an aliphatic side chain, and the main chain contains a nitrogen-containing aromatic heterocycle, so that the resolution targets of low curing temperature, low thermal expansion coefficient, high adhesion with a copper substrate and development on cyclopentanone can be simultaneously achieved.

Drawings

FIG. 1 is a pattern with a lithographic resolution of 2 μm obtained in example 1;

FIG. 2 is a pattern with a lithographic resolution of 3 μm obtained in example 2.

Detailed Description

R ₁ is a group of a polymerizable olefin structure of C4-C20;

m at least comprises one of an amine group and an anhydride group;

n is the degree of polymerization, n=2 to 150.

Specifically, in formula I, X is a tetravalent organic group, specifically the residue of a tetracarboxylic dianhydride polymerized from a polyamic acid ester. In some embodiments of the invention, X comprises at least one of the following groups:

in some preferred embodiments of the invention, to achieve the low coefficient of thermal expansion object of the invention, X comprises at least one of the following groups:

In the formula I, Y is a divalent organic group and is the residue of diamine polymerized by polyamide acid ester. In some embodiments of the present invention, in order to meet the requirements of low curing temperature, high adhesion to copper substrates, Y comprises at least a nitrogen-containing aromatic heterocyclic structure group, preferably Y comprises at least one of the following groups:

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

in some embodiments of the invention, Y further comprises a nitrogen-free heterocyclic structure group comprising at least one of the following groups:

the molar amount of the nitrogen-containing aromatic heterocyclic structure groups is >60% of the total molar amount of the groups Y, and may be 61% -100%, for example.

In the present invention, the side chain R ₁、R₂ is the ester moiety. R ₁ is a group of a polymerizable olefin structure of C4 to C20, R ₁ is preferably a group of an unsaturated ester structure of C4 to C10, and R ₁ is more preferably a group of an acrylate structure. R ₁ further preferably includes at least one of the following groups:

R ₂ is C1-C12 straight-chain or branched-chain alkyl or straight-chain or branched-chain alkyl containing ether bond-O-. R ₂ is preferably a C4-C8 linear or branched alkyl group, and at least one of the linear or branched alkyl groups containing methoxy.

In the formula I, M at least comprises one of an amino group and an anhydride group.

M is selected from one of the following groups:

Z is-O-, -COO-, -NH-;

In the present invention, n is a polymerization degree, n=2 to 150, may be 2, 5,10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, or any value between 2 to 150, and is preferably 5 to 100.

When the polymerization degree n is 2 to 150, the weight average molecular weight is (0.5 to 10) ×10 ⁴, and when n is 5 to 100, the weight average molecular weight is (1 to 3) ×10 ⁴.

The high dissolution rate of the polyamic acid ester resin in cyclohexanone as a developer is not reduced by the selection or optimization of dianhydride, diamine and end group structure in the polyamic acid ester resin, and after exposure, enough dissolution rate difference between an exposure area and a non-exposure area can be formed, so that a negative photoetching pattern can be formed. The high dissolution rate is a dissolution rate in cyclohexanone of >0.1 μm/s. The preferable dissolution rate is 0.15 to 1.0 μm/s. With this dissolution rate can be a necessary factor for high lithographic resolution. The high lithographic resolution is such that <10 μm patterned features, preferably <8 μm patterns, can be formed.

In order to achieve the aims of low curing temperature, low thermal expansion coefficient, high adhesion with copper base material and high resolution ratio during cyclopentanone development, the photosensitive polyamic acid ester provided by the invention has the following characteristics in structure:

1) Besides amide bond, the main chain at least comprises a nitrogen-containing aromatic heterocyclic structure, so that the catalysis of the tertiary amine structure based on the nitrogen-containing aromatic heterocyclic structure to the curing process is realized, the curing temperature is further reduced, and meanwhile, the coordination of the nitrogen-containing aromatic heterocyclic structure and copper can realize high binding force of copper, improve water oxygen barrier property and inhibit migration of copper ions in application, so that the reliability of a product is improved.

2) The side chains R1, R2 are derived from two different alcohols. At least one allyl structure to make the polyamide acid ester have photosensitive property, can be photo-crosslinked to reduce the dissolution rate in the developer and realize the photoetching aim, and at least one structure containing fatty chains to improve the dissolution rate of photosensitive polyamide acid ester 001 in the developer with cyclopentanone as the developer.

3) The dianhydride and diamine of the photosensitive polyamic acid ester 001 have more rigid structures for the purpose of low thermal expansion coefficient, wherein the rigid structures comprise rigid benzene, biphenyl, aromatic heterocycle, direct connection structure of benzene and aromatic heterocycle, and symmetrical structures when the rigid structures are linked into a polyimide main chain.

4) The end group A contains at least one fatty chain-containing structure to increase the dissolution rate of the photosensitive polyamic acid ester 001 in cyclopentanone as a developer.

B) Adding an activating agent into the diacid diester reaction liquid to react to obtain a reaction system;

The specific chemical reaction formula is as follows:

wherein the dianhydride compound has a structure shown in a formula II:

the diamine compound has a structure shown in a formula III:

H ₂N-Y-NH₂ formula III.

The process for preparing the polyacid esters of the invention is a conventional well known two-step process. It is important to control the reaction temperature <20 ℃ during the reaction to prevent the formation of by-products, such as cross-linked by-products, from reducing the product yield.

Concretely, dianhydride compounds, primary alcohol containing R ₁, primary alcohol containing R ₂, catalyst and solvent are added into a reaction vessel, and the reaction is carried out for 4-24 hours at the controlled temperature of <20 ℃ to obtain diacid diester.

The conversion of the reaction of the diacid diester produced according to the invention needs to be >98% and can be determined by known methods, for example, the conversion of the reaction can be determined from NMR so that the yield of the product is sufficiently high.

The solvent is common solvent for polyimide polymerization, and can be one or more selected from dimethylformamide, dimethylacetamide, methylpyrrolidone, dimethyl sulfoxide, butyrolactone, cyclohexanone and cyclopentanone.

The catalyst is tertiary amine catalyst, preferably pyridine, substituted pyridine, quinoline, isoquinoline, triethylamine, dimethylaminopyridine and imidazole. The catalyst may be added in an amount of 20 to 300% of the dianhydride compound, and may be added in an amount of 20%, 50%, 100%, 120%, 140%, 150%, 160%, 180%, 200%, 250%, 300%, or 20 to 300%, preferably 100 to 200%.

Then, an activator is added into the diacid diester reaction liquid to react, and a reaction system is obtained. The reaction temperature is less than 20 ℃, the reaction time is 0.5-4 h, and the reaction time can be any value between 0.5, 1,2, 3, 4 or 0.5-4 h.

The activator is capable of activating diacid and polycondensing with diamine, and the invention needs to perform the diacid activation first. The activator includes a method of using an amide condensing agent, or a method of forming an acid halide from a diacid. Methods of using amide condensing agents include the use of carbodiimides, carbonyldiimidazoles, preferably dicyclohexylcarbodiimide, diisopropylcarbodiimide, carbonyldiimidazole. The method for forming the acid halide preferably uses thionyl chloride or phosphorus oxychloride.

Then, diamine compound and end group control agent A-M are added into the reaction system to carry out polycondensation reaction, thus obtaining the photosensitive polyimide resin.

The reaction temperature is less than 20 ℃, the reaction time is 4-24 hours, and the reaction time can be any value between 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24 or 4-24 hours.

The end control agent A-M is selected from amine group-containing end control agents or anhydride group-containing end control agents, M at least comprises one of amine groups and anhydride groups, and A at least comprises a fatty chain structure.

Wherein Z is-O-, -COO-, -NH-, R ₃ is C1-C12 straight-chain or branched-chain alkyl or straight-chain or branched-chain alkyl containing ether bond-O-, and preferably R ₃ is C4-C10 straight-chain or branched-chain alkyl containing ether bond-O-.

Further preferably, the amine group containing end-group controlling agent comprises at least one of the following compounds:

When the A-M is selected from the amine-containing end group control agent, the molar ratio of the dianhydride compound (primary alcohol containing R ₁ +primary alcohol containing R ₂) to the diamine compound to the amine-containing end group control agent is 100 to 105, 94 to 98 and 8~4;

When the A-M is selected from the group consisting of the anhydride group-containing end-group control agents, the molar ratio of the dianhydride compound (primary alcohol containing R ₁ +primary alcohol containing R ₂) to the diamine compound (the anhydride group-containing end-group control agent) is (94-98): 100-105): 100 (8~4).

In the invention, the molar ratio of the primary alcohol containing R ₁ to the primary alcohol containing R ₂ is 100 (20-60), and can be any value between 100:20, 100:25, 100:30, 100:35, 100:40, 100:45, 100:50, 100:55, 100:60, or 100 (20-60), preferably any value between 100 (30-50).

As an alternative to the highest molecular weight for forming the polycondensation polymer, it is preferred to bring the molar ratio of dianhydride to diamine closest to 1:1.

After the reaction is finished, adding ethanol into the reaction system to terminate the reaction, and adding a large amount of deionized water to precipitate the polyamic acid ester. Filtering to separate the crude product. And (5) drying in vacuum to obtain the product polyamide acid ester.

The molecular weight, viscosity and dissolution rate in cyclopentanone of the resultant polyamic acid ester product were analytically tested.

The photoresist is a composite slurry containing the polyimide resin, and at least comprises a photoinitiator. Auxiliary components for improving the effect can also be added. As the auxiliary component, a coupling agent, a polymerization inhibitor, a solvent, and the like may be included.

Specifically, the photoresist includes:

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.

The photoresist comprises 1-20 parts by mass of photoinitiator based on 100 parts by mass of 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 1-20 parts by mass.

The photoinitiator is a compound capable of generating free radicals under illumination and polymerizing a compound containing an olefinically unsaturated group. The initiator for generating free radicals by illumination is at least one selected from the group consisting of benzophenone, N-alkylaminoacetophenone, oxime ester, acridine, phosphine oxide and 2,4, 5-triphenylimidazole. Specific examples thereof include 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' -methyldiphenyl sulfide, benzil derivatives selected from benzil dimethyl ketal, benzoin compounds having insufficient blood pressure, methylbenzin and ethylbenzoin, benzoin ether compounds selected from benzoin methyl ether, benzoin ethyl ether and benzoin phenyl ether, oxime ester compounds selected from 1, 2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyl oxime), ethanone, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazole ] -1- (O-phenyl) -3-acetyl ] -N- (N-phenyl-glycine-phenyl) oxime, and benzoin derivatives selected from 1, 2-octanedione, N-phenylphosphine oxide derivatives.

In the present invention, the photoinitiator may be used alone or in combination of 2 or more. Among the above photoinitiators, one or more of aromatic ketone and oxime ester compounds are more preferable, particularly from the viewpoint of improving resolution.

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

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

R ₅ is at least one substituent selected from amino, aminoethylamino, epoxy, phenylamino, ureido and isocyanate. R ₅ preferably contains at least one of an amino ethylamino group, a phenylamino group, and an isocyanate group substituent from the viewpoint of improving resolution and improving adhesiveness of the remaining copper wiring layer.

R ₄ is an alkyl group having 1 to 4 carbon atoms. Preferably methyl, ethyl, propyl.

As the epoxy group-containing silane coupling agent, one or more of 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane and 3-epoxypropoxypropyltriethoxysilane are preferable.

As the phenylamino group-containing silane coupling agent, N-phenyl-3-aminopropyl trimethoxysilane is preferred.

As the amino-ethylamino-containing silane coupling agent, N-aminoethyl-3-aminopropyl trimethoxysilane is preferable.

As the silane coupling agent containing an isocyanate group, 3-isocyanatopropyl triethoxysilane is preferable.

The photoresist further comprises 0-10 parts by mass of polymerization inhibitor, which can be 0, 1,2, 3,4, 5, 6, 7, 8, 9,10 or any value between 0-10 parts by mass, based on 100 parts by mass of photosensitive polyimide resin.

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

The aromatic hydroxyl group-containing compound is preferably one or more of 4-methoxyphenol, 2, 6-di-t-butyl-4-methylphenol, hydroquinone, methyl hydroquinone, t-butylhydroquinone, 4-thiobis (3-methyl-6-t-butylphenol), 2' -methylenebis (4-methyl-6-t-butylphenol), phenol resins and cresol resins.

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 are preferable.

As the N-oxide compound, one or more of phenyl-t-butylnitrone, 5-dimethyl-1-pyrroline-N-oxide, 4-methylmorpholine-N-oxide, pyridine-N-oxide, 4-nitropyridine-N-oxide and isonicotinic acid-N-oxide are preferable.

As the quinone compound, one or more of p-benzoquinone, p-dimethyl quinone, p-toluquinone, 2, 6-dimethyl-1, 4-benzoquinone, 2-methylanthraquinone, and 5, 12-naphthaquinone are preferable.

As the compound of the N-oxygen radical, preferably 2, 6-tetramethylpiperidine 1-oxyl, 4-cyano-2, 6-tetramethylpiperidine 1-oxyl one or more of 4-amino-2, 6-tetramethylpiperidine 1-oxyl radicals.

As the hindered phenol compound, one or more of 2, 6-di-t-butyl-4-methylphenol, 2, 5-di-t-butyl-hydroquinone, pentaerythritol-tetrakis [ 3- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate ] are preferable.

The polymerization inhibitor is preferably an aromatic hydroxyl group-containing compound and a nitroso compound, for example, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 4-methoxyphenol and 2, 6-di-t-butyl-4-methylphenol, from the viewpoints of storage stability, resolution, and development residual film rate of the resist. The polymerization inhibitor may be used alone, but it is preferable to use at least 2 or more different compounds.

The photoresist further comprises 150 to 400 parts by mass of a solvent based on 100 parts by mass of the photosensitive polyimide resin, and the solvent may be 150, 200, 250, 300, 350, 400, or any value between 150 to 400 parts by mass.

In the present invention, 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-dimethylacetamide, dimethylsulfoxide, diethylene glycol dimethyl ether, cyclopentanone, gamma-butyrolactone, alpha-acetyl-gamma-butyrolactone, tetramethylurea, 1, 3-dimethyl-2-imidazolidinone, N-cyclohexyl-2-pyrrolidone and 3-methoxy-N, N-dimethylpropionamide. The solvent may be used alone or in combination of 2 or more.

The specific implementation process comprises the following steps:

1) Coating, namely coating polyimide photoresist solution on the surface of a substrate;

2) Pre-drying the solvent;

3) Exposing, namely illuminating the resin layer through a mask plate;

4) Developing, namely treating the resin layer by using a developing solution;

5) And (3) heat curing, namely heating at high temperature to form the patterning.

Specific:

1) Coating, namely coating polyimide photoresist solution on a substrate. The coating method selected in the present invention is a method known to those skilled in the art for coating a photosensitive resin, and may be a coating method using spin coating, bar coating, blade coating, screen printing, spraying, or the like.

2) As the drying method, there may be mentioned, for example, air drying, heat drying by an oven or a heating plate, vacuum drying and the like, as known to those skilled in the art. The drying can be performed at 50-140 ℃ for 1 minute-1 hour.

3) The exposure is performed by exposing the dried resin layer with or without a photomask or a grating having a pattern using an exposure apparatus such as a contact lithography machine, a projection exposure machine, or a stepper, and by using an ultraviolet light source or the like.

Post Exposure Bake (PEB) and/or pre-development bake may also be performed due to considerations of improving light sensitivity. Regarding the range of the baking condition, the temperature is preferably 40 to 120 ℃, may be any value of 40, 50, 60, 70, 80, 90, 100, 110, 120, or 40 to 120 ℃, and the time is preferably 10 to 240 seconds.

4) Developing, namely developing and removing the unexposed part in the exposed photosensitive resin layer. As a developing method for developing the resin layer after exposure, there are known developing methods for photoresist, for example, a spin spray method, an immersion method accompanied by ultrasonic treatment, and the like.

As the developing solution used in the development, the invention preferably selects cyclopentanone so as to adapt to most of the current application scenes and better environmental protection requirements.

5) Thermal curing the cured pattern formed by imidizing the polyamic acid ester according to the invention by heating, thereby converting it into polyimide. At the same time, the photosensitive component in the system is degraded and volatilized by heating. As a method of heat curing, a method based on a heating plate, a method using an oven, a method using a temperature-raising oven capable of setting a temperature program, and the like can be mentioned.

The curing heating of the invention is carried out at a maximum temperature of <200 ℃, preferably 150-180 ℃ and for 30 minutes-5 hours. The atmosphere gas during the heat curing may be air or an inert gas such as nitrogen or argon.

The linear thermal expansion coefficient of the patterned film layer is between 5 and 20ppm/K, the modulus of the patterned film layer reaches more than 4.0GPa, the elongation at break is more than 50%, and the tensile strength is more than 200MPa, so that the patterned film layer has the characteristics of high mechanical property and low thermal expansion coefficient when the curing temperature is low.

In order to further understand the present invention, the low-temperature cured, low thermal expansion photosensitive polyimide resin and the photoresist thereof provided by the present invention are described below with reference to examples, and the scope of the present invention is not limited by the following examples.

Example 1

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.13mol of 4, 4-pyromellitic dianhydride (PMDA) and 0.1mol of hydroxyethyl methacrylate, 0.03mol of ethylene glycol monomethyl ether and 0.26mol of pyridine into 100g of N, N-Dimethylformamide (DMF) solvent, continuously stirring, reducing the reaction temperature to be within a range of 20 ℃, reacting for 4 hours till the whole reaction is dissolved, adding 0.26mol of dicyclohexylcarbodiimide (PMDA) into a transparent solution, controlling the reaction temperature to be within a range of 20 ℃, activating for 2 hours, continuously adding 0.122mol of 2, 5-bis (4-aminophenyl) Pyridine (PRD) and 0.0104mol of para-aminoanisole, continuously polycondensing for 5 hours after the temperature returns to the room temperature, pouring the reaction product into absolute ethanol for precipitation after the reaction is stopped after the reaction is added into the reaction system, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of photosensitive polyimide resin, 0.04g of benzophenone, 0.04g of 2- (3, 4-epoxycyclohexyl) ethyl trimethoxysilane, 0.04g of 2, 6-di-tert-butyl-p-methylphenol and 3.0g N-methyl-2-pyrrolidone (NMP) are taken and stirred uniformly to obtain a negative photosensitive polyimide composition.

Example 2

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.1386mol of 3,3', 4' -biphenyl tetracarboxylic dianhydride (BPDA) and 0.1mol of hydroxyethyl methacrylate, 0.04mol of ethylene glycol monoethyl ether and 0.277mol of quinoline into 100g of N, N-dimethylacetamide (DMAc) solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃, reacting for 6 hours till the whole reaction is dissolved, adding 0.277mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating for 4 hours, continuously adding 0.079mol PRD,0.053mol4,4' -diaminodiphenyl ether (ODA) and 0.0111mol of para-aminoanisole, continuously performing polycondensation for 10 hours, adding ethanol into the reaction system after the temperature returns to room temperature, stopping the reaction, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of photosensitive polyimide resin, 0.1g of N-alkylaminoacetophenone, 0.06g of N-phenyl-3-aminopropyl trimethoxysilane, 0.06g of 4-methoxyphenol and 4.0g of DMF are taken and stirred uniformly to obtain a negative photosensitive polyimide composition.

Example 3

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.147mol of 3,3', 4' -Benzophenone Tetracarboxylic Dianhydride (BTDA) and 0.1mol of hydroxyethyl methacrylate, 0.05mol of ethylene glycol monomethyl ether and 0.294mol of triethylamine in 100g of gamma-butyrolactone solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃, reacting for 8 hours until the reaction is completely dissolved, adding 0.294mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating and reacting for 3 hours, continuously adding 0.099mol of 2, 5-bis (4-aminophenyl) Pyrimidine (PRM), 0.042mol of 4,4' -diamino-2, 2' -dimethyl-1, 1' -biphenyl (mTB) and 0.0088mol of p-aminobenzoic acid, continuously polycondensing for 15 hours, after the temperature returns to room temperature, adding ethanol into a reaction system, stopping the reaction, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of photosensitive polyimide resin, 0.2g of N, N ' -tetramethyl-4, 4' -diaminobenzophenone (Michler's ketone), 0.1g of N-aminoethyl-3-aminopropyl trimethoxysilane, 0.1g of hydroquinone and 5.0g of DMAc are taken and stirred uniformly to obtain a negative photosensitive polyimide composition.

Example 4

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.125mol of 1, 3-dioxo-1, 3-dihydroisobenzofuran-5-yl 1, 3-dioxo-1, 3-dihydroisobenzofuran-5-carboxylate (JFCA) and 0.1mol of hydroxyethyl methacrylate, 0.03mol of ethylene glycol monomethyl ether, 0.25mol of dimethylaminopyridine into 100g of dimethyl sulfoxide (DMSO) solvent, continuously stirring, reducing the reaction temperature to 20 ℃ range, reacting for 10 hours until the reaction is completely dissolved, adding 0.25mol of DCC into a transparent solution, controlling the reaction temperature to be within the range of 20 ℃, activating the reaction for 2 hours, continuously adding 0.097mol of 2- (4-aminophenyl) -5-aminobenzooxazol (BOA), 0.024mol of 2,2 '-bis (trifluoromethyl) -4,4' -diaminobiphenyl (TFDB) and 0.0063mol of methyl p-aminobenzoate, continuously polycondensing the polyimide for 15 hours, after the temperature is returned to the room temperature, adding ethanol into the reaction system, stopping the reaction system, pouring the ethanol into the reaction system, and finally, precipitating the polyimide resin without water, and obtaining the polyimide through photosensitive reaction.

2G of photosensitive polyimide resin, 0.3g of 4-methoxy-4' -dimethylamino benzophenone, 0.16g of 3-isocyanatopropyl triethoxysilane, 0.16g of methyl hydroquinone and 6.0g of cyclopentanone are taken, and the mixture is stirred and mixed uniformly to obtain a negative photosensitive polyimide composition.

Example 5

Introducing nitrogen into a reaction vessel at room temperature, continuously stirring 0.133mol of bis (1, 3-dioxo-1, 3-dihydroisobenzofuran-5-carboxylic acid) 1, 4-phenylene Ester (ESDA) and 0.1mol of hydroxyethyl methacrylate, 0.04mol of ethylene glycol monoethyl ether, 0.266mol of imidazole into 100g of DMAc solvent, reducing the reaction temperature to be within 20 ℃ to react for 12 hours until the mixture is completely dissolved, adding 0.266mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃ to activate the mixture for 3 hours, continuously adding 0.1176mol of 2- (4-aminophenyl) -5-aminobenzimidazole (APBIA), 0.0131mol of ODA and 0.0053mol of p-aminobenzoic acid, continuously polycondensing the mixture for 20 hours, adding ethanol into the reaction system to terminate the reaction after the temperature returns to room temperature, pouring the reaction product into absolute ethanol to precipitate, and finally filtering and drying the reaction product to obtain the photosensitive polyimide resin.

2G of a photosensitive polyimide resin, 0.4g of 1, 2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyl oxime) ],0.2g of 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 0.2g of tertiary butyl hydroquinone and 8.0gDMF g of a negative photosensitive polyimide composition were taken and stirred uniformly.

Example 6

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.141mol of PMDA and 0.1mol of hydroxyethyl methacrylate, 0.05mol of ethylene glycol monomethyl ether and 0.28mol of pyridine into 100g of NMP solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃, reacting for 14 hours until the mixture is completely dissolved, adding 0.28mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating the mixture for 4 hours, continuously adding 0.15mol of PRD and 0.012mol of 5-methoxy-isobenzofuran-1, 3-dione, continuously performing polycondensation for 24 hours, after the temperature returns to the room temperature, adding ethanol into the reaction system, stopping the reaction, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of photosensitive polyimide resin, 0.04g of benzophenone, 0.04g of 2- (3, 4-epoxycyclohexyl) ethyl trimethoxy silane, 0.04g of 2, 6-di-tert-butyl p-methylphenol and 3.0g of gamma-butyrolactone are taken and stirred uniformly to obtain a negative photosensitive polyimide composition.

Example 7

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.1223mol of BPDA and 0.1mol of hydroxyethyl methacrylate, 0.03mol of ethylene glycol monomethyl ether and 0.244mol of pyridine into 100g of gamma-butyrolactone solvent, continuously stirring, reducing the reaction temperature to 20 ℃, reacting for 16 hours till the whole reaction is dissolved, adding 0.244mol of DCC into a transparent solution, controlling the reaction temperature to 20 ℃, activating for 2 hours, continuously adding 0.077mol PRD,0.051mol ODA mol of 1, 3-dioxo-1, 3-dihydroisobenzofuran-5-carboxylic acid methyl ester, continuously polycondensing for 24 hours, adding ethanol into the reaction system to terminate the reaction after the temperature returns to room temperature, precipitating the reaction product into absolute ethanol, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of photosensitive polyimide resin, 0.1g of N-alkylaminoacetophenone, 0.06g of N-phenyl-3-aminopropyl trimethoxysilane, 0.06g of 4-methoxyphenol and 4.0g of DMSO are taken, and uniformly stirred and mixed to obtain a negative photosensitive polyimide composition.

Example 8

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.132mol of BTDA and 0.1mol of hydroxyethyl methacrylate, 0.04mol of ethylene glycol monomethyl ether and 0.26mol of pyridine into 100g of DMF solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃ for 16 hours until the mixture is completely dissolved, adding 0.26mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating the mixture for 3 hours, continuously adding 0.096mol PRM,0.041mol mTB and 0.0082mol of 5-methoxy-isobenzofuran-1, 3-dione, continuously carrying out polycondensation for 4 hours, adding ethanol into a reaction system after the temperature returns to room temperature, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

Taking 2g of photosensitive polyimide resin, 0.2g of N, N ' -tetramethyl-4, 4' -diaminobenzophenone (Michler's ketone), 0.1g of N-aminoethyl-3-aminopropyl trimethoxysilane, 0.1g of hydroquinone and 5.0g of DMAc, and stirring and mixing uniformly to obtain a negative photosensitive polyimide composition

Example 9

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.140mol JFCA and 0.1mol of hydroxyethyl methacrylate, 0.05mol of ethylene glycol monoethyl ether and 0.28mol of pyridine into 100g of gamma-butyrolactone solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃, reacting for 18 hours till the whole reaction is dissolved, adding 0.28mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating the reaction for 4 hours, continuously adding 0.115mol BOA,0.029mol TFDB and 0.0072mol of 1, 3-dioxo-1, 3-dihydroisobenzofuran-5-carboxylic acid methyl ester, continuously polycondensing for 6 hours, adding ethanol into a reaction system to terminate the reaction after the temperature returns to room temperature, precipitating the reaction product into absolute ethanol, and finally filtering and drying to obtain the photosensitive polyimide resin.

Example 10

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.12mol of ESDA and 0.1mol of hydroxyethyl methacrylate, 0.03mol of ethylene glycol monomethyl ether and 0.24mol of pyridine into 100g of NMP solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃, reacting for 18 hours till the whole reaction is dissolved, adding 0.24mol of DCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating the reaction for 2 hours, continuously adding 0.111molAPBIA,0.012mol ODA and 0.0050mol of 5-methoxy-isobenzofuran-1, 3-dione, continuously carrying out polycondensation for 10 hours, adding ethanol into a reaction system after the temperature returns to the room temperature, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of a photosensitive polyimide resin, 0.4g of 1, 2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyl oxime) ],0.2g of 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 0.2g of tertiary butyl hydroquinone and 8.0gDMSO g of a negative photosensitive polyimide composition were taken and stirred uniformly.

Comparative example 1

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.13mol of 4,4' -oxydiphthalic anhydride (ODPA) and 0.1mol of hydroxyethyl methacrylate, 0.03mol of ethylene glycol monomethyl ether and 0.26mol of pyridine into 100g of DMF solvent, continuously stirring, reducing the reaction temperature to be within 20 ℃, reacting for 4 hours till all the pyridine is dissolved, adding 0.26molDCC into a transparent solution, controlling the reaction temperature to be within 20 ℃, activating the reaction for 2 hours, continuously adding 0.13mol of ODA, continuously performing polycondensation for 5 hours, adding ethanol into a reaction system after the temperature returns to the room temperature, stopping the reaction, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

2G of photosensitive polyimide resin, 0.04g of benzophenone, 0.04g of 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 0.04g of 2, 6-di-tert-butyl-p-methylphenol and 3.0g of NMP are taken, and the mixture is stirred and mixed uniformly to obtain a negative photosensitive polyimide composition.

Comparative example 2

Introducing nitrogen into a reaction vessel at room temperature, dissolving 0.13mol of PMDA and 0.13mol of hydroxyethyl methacrylate in 100g of DMF solvent, continuously stirring, reducing the reaction temperature to 20 ℃, reacting for 4 hours until the mixture is completely dissolved, adding 0.26mol of DCC into a transparent solution, controlling the reaction temperature to 20 ℃, activating for 2 hours, continuously adding 0.13mol of PRD, continuously polycondensing for 5 hours, adding ethanol into the reaction system after the temperature returns to room temperature, stopping the reaction, pouring the reaction product into absolute ethanol for precipitation, and finally filtering and drying to obtain the photosensitive polyimide resin.

Performance testing

1. Performance test of photosensitive polyimide resin

The molecular weight, viscosity and dissolution rate in cyclopentanone of the resultant polyamic acid ester resin product were analytically tested.

2. Photosensitive polyimide composition performance test

The polyimide photoresist solution can be used for forming patterned morphology through the processes of coating, prebaking, exposing, developing and heat curing.

1) Coating, namely spin-coating polyimide photoresist solution on a silicon substrate.

2) Pre-baking, namely heating and drying the silicon wafer on a heating plate, and drying the silicon wafer at 100 ℃ for 10 minutes.

3) The exposure is performed by exposing the dried resin layer with an ultraviolet light source or the like using a projection type exposure machine and a photomask having a pattern. The Post Exposure Bake (PEB) condition was at a temperature of 70 ℃ for 120 seconds.

4) Developing by rotary spraying using cyclopentanone as a developer.

5) And (3) performing thermal imidization treatment on the pattern by using an oven in a step heating mode, wherein the step heating mode is to keep the temperature at 100 ℃ for 1 hour and 200 ℃ for 1 hour, and the heating rate is 10 ℃ per minute.

Then cooled to room temperature, the pattern is peeled off from the substrate, and the resolution of the inclined plane of the film is observed by using an ESEM XL-30 type field emission environment scanning electron microscope.

Imidization rate of the film, namely taking a10 mu m PSPI film prepared after patterning, testing the infrared spectrum of the film by adopting a Fourier infrared spectrometer, taking the ratio of C-N stretching vibration at 1380cm ^-1 and benzene ring stretching vibration characteristic peak at 1500cm ^-1 of the sample, treating the PSPI at 350 ℃ for 1h as a 100% imidization sample, and calculating to obtain the imidization rate of each PSPI sample.

Thermal expansion coefficient is that a 10 mu m PSPI film prepared after patterning is taken, and the thermal expansion coefficient of the PI film is tested on a Q400 thermomechanical analyzer of TMA company in air, wherein the temperature rising rate is 3 ℃ per minute, and the temperature range is 25-300 ℃.

Mechanical properties the 10. Mu mPSPI film prepared after patterning was tested for tensile strength (sigma m), tensile modulus (Et) and elongation at break (epsilon b) at a tensile rate of 5mm/min using an INSTRON-1121 type universal tester from Instron.

The photosensitive polyimide resin test results of each of examples 1 to 10 and comparative examples 1,2 are shown in table 1:

TABLE 1

The photosensitive polyimide compositions of examples 1 to 10 and comparative examples 1 and 2 were tested as shown in tables 2 and 3:

TABLE 2

TABLE 3 Table 3

	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

From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

The tertiary amine structure of the nitrogen-containing aromatic heterocycle is introduced into the polyimide polymer chain, the curing temperature of the film is lower than 200 ℃ to realize complete imidization due to the catalysis effect, the structure containing the aliphatic chain is introduced into the side chain to improve the dissolution speed of the photosensitive polyamide acid ester in cyclopentanone, and the rigid structure is introduced into the main chain structure to ensure that the PSPI film has a lower thermal expansion coefficient of 5-20 ppm K ^-1, and the lower the thermal expansion coefficient is along with the increase of the amount of the rigid diamine, the higher the elastic modulus is. The end group is introduced into a 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 the higher photoetching resolution is less than or equal to 5 mu m. Referring to fig. 1 and 2, fig. 1 is a pattern having a lithographic resolution of 2 μm obtained in example 1, and fig. 2 is a pattern having a lithographic resolution of 3 μm obtained in example 2.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims

1. The low-temperature curing and low-thermal expansion photosensitive polyimide resin is characterized by having a structure shown in a formula I:

R ₁ is a group of a polymerizable olefin structure of C4-C20;

m at least comprises one of an amine group and an anhydride group;

n is the degree of polymerization, n=2 to 150.

2. The photosensitive polyimide resin according to claim 1, wherein 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 having no nitrogen heterocyclic structure, the group having no nitrogen heterocyclic structure comprising at least one of the following groups:

7. The photosensitive polyimide resin according to claim 1, wherein R1 comprises at least one of the following groups:

8. The photosensitive polyimide resin according to claim 1, wherein M contains 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-;

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

10. A method for preparing the low-temperature-cured low-thermal-expansion photosensitive polyimide resin according to any one of claims 1 to 9, comprising the following steps:

11. The method according to claim 10, wherein in step a), the reaction temperature is <20 ℃ and the reaction time is 4-24 hours;

12. The method of claim 10, wherein the end-control agent a-M is selected from amine group-containing end-control agents or anhydride group-containing end-control agents;

13. A photoresist comprising the low temperature cured, low thermal expansion photosensitive polyimide resin according to any one of claims 1 to 9.

14. The photoresist according to claim 13, comprising:

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 according to claim 14, wherein the photoinitiator is selected from the group consisting of compounds comprising benzophenone, N-alkylaminoacetophenone, oxime esters, acridine, phosphine oxide, and 2,4, 5-triphenylimidazole structures;

the coupling agent is selected from silane coupling agents;

16. A method of patterning a photoresist according to any one of claims 13 to 15, comprising the steps of:

17. The patterning process of claim 16, wherein the heat curing is at a temperature of 200 ℃ or less for a time of 0.5 to 5 hours, and wherein the heat curing atmosphere is selected from air, nitrogen, or argon.