A photosensitive polyimide polymer, a photosensitive polyimide film and a preparation method and application thereof

Abstract

The present application relates to the technical field of photosensitive resin material, in particular to a photosensitive polyimide polymer, a photosensitive polyimide film and a preparation method and application thereof, the preparation method of the photosensitive polyimide polymer comprises the following steps: under the protection of nitrogen, dissolving dianhydride in an organic solvent, and slowly adding diamine 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and diamine photosensitive monomer in batches, to obtain a polyamide acid solution by reaction; after the polyamide acid solution is cooled to 0-10 DEG C, TFAA and TEA are added, and then the intermediate is synthesized by reaction at room temperature, and then DFA is added to react at 40-60 DEG C, to synthesize the photosensitive polyimide polymer. The diamine photosensitive monomer compound used in the present application has a very beneficial light response to ultraviolet light, and the pyridine ring is changed after being irradiated by ultraviolet light, so that the fluorescence emission is changed, and the photosensitive polyimide polymer can be copolymerized to the photosensitive polyimide polymer after the isocyanide pretreatment and the grafted ester unit.

Description

Technical Field

[0001] This invention relates to the field of photosensitive resin materials technology, specifically to a photosensitive polyimide polymer, a photosensitive polyimide film, its preparation method, and its application. Background Technology

[0002] High-performance plastics are attracting significant attention due to their potential applications in aerospace, automotive, electronics, and related industries. Polyimides, in particular, are widely used as insulating materials for microelectronic devices due to their excellent properties, such as thermal and chemical stability and low dielectric constant. They are mostly produced by the reaction of aromatic dianhydrides with aromatic diamines. This reaction occurs via a soluble polyamic acid intermediate, which undergoes a condensation reaction upon further heating to form polyimides and release water. Because these aromatic polyimides are insoluble in organic solvents and have high melting points, in most cases, polyamic acid is first prepared, then processed into a predetermined shape, and subsequently formed into polyimides through a thermal cyclization reaction. However, this processing method using polyamic acid (PAA) as a precursor has some significant limitations. For example, the photosensitive polyamic acid system composed of polyamic acid and diazidonaphthoquinone sulfonate is difficult to achieve a large solubility difference between exposed and unexposed areas, making it insufficient for constructing fine patterns. Due to technical barriers such as excessively high thermal imidization temperatures and large coefficients of thermal expansion, controlling the dissolution rate of PAA in alkaline solutions is an important area of ​​research to improve the sensitivity and resolution (minimum exposure width) of the photolithography process.

[0003] Esterification of PAA with hydrophobic treatment is one of the most common methods, but direct esterification results in a low degree of esterification and a still relatively fast dissolution rate. Polyisoimides, due to their excellent processing properties and ease of conversion into polyimides, are considered ideal precursors for photosensitive polyimides. 1,4-Dihydropyridine (DHP) and its derivatives, due to their unique photochemical reactivity, have become ideal building blocks for constructing photoresponsive materials. Under light irradiation, the DHP ring can undergo a controllable oxidative dehydrogenation reaction, transforming into the corresponding pyridine derivative. This process is accompanied by significant changes in its conjugated system, fluorescence properties, and chemical reactivity. However, in the process of introducing the DHP structure into polymer systems to prepare high-performance photosensitive materials, existing methods for synthesizing photosensitive monomers have many drawbacks, as follows:

[0004] 1) Complex synthetic routes and low yields: Existing synthetic routes for monomers containing DHP functional groups, especially those with multiple reactive groups, are often lengthy and cumbersome. The cumulative yield of multi-step reactions is usually low, which greatly increases production costs and limits their large-scale application. For example, some methods require harsh reaction conditions, such as ultra-low temperatures or anhydrous and oxygen-free environments, which place high demands on equipment and operation, and result in many side reactions, making it difficult to separate and purify the target product.

[0005] 2) Poor structural tunability: Many existing synthetic methods are quite rigid, making it difficult to adjust the molecular structure of monomers simply by changing the starting materials. For example, changing the substituents of the central photosensitive core, adjusting the length or flexibility of the linker arms, or changing the type of terminal functional groups. This difficulty in "customized" synthesis hinders the systematic optimization of monomer photoelectric properties and polymerization reactivity.

[0006] 3) Stability issues: Some DHP derivatives are sensitive to light, heat or acidic environments, and are prone to decomposition or unexpected side reactions during synthesis or purification, resulting in low product purity, low yield, and inconvenience in storage and use. Summary of the Invention

[0007] In view of this, the present invention provides a photosensitive polyimide polymer, a photosensitive polyimide film, a method for preparing the same, and its applications, to solve the technical barriers of existing technologies such as excessively high thermal imidization temperatures and excessively large coefficients of thermal expansion, and to address the technical problems of improving the sensitivity and resolution of the photolithography process. The present invention enhances the degree of esterification reaction by grafting ester groups onto the isoimidization pretreatment of the polyamic acid (PAA) precursor, thereby achieving a low thermal imidization temperature (less than 200°C) and a low coefficient of thermal expansion (26 ppm K). -1 ) and an exposure sensitivity of 246 mJ / cm 2 And excellent technical performance with a resolution of 5μm.

[0008] To achieve the above objectives, the present invention provides a method for synthesizing a novel diamine photosensitive monomer containing dihydropyridine, comprising the following steps:

[0009] S1, under nitrogen protection, dianhydride is dissolved in an organic solvent, and diamine 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP) and diamine monophotosensitive element are slowly added in batches to obtain polyamic acid (PAA) solution.

[0010] The dianhydride is selected from 3,3,4,4-biphenyltetracarboxylic dianhydride (BTDA) or 4,4'-(hexafluoroisopropene) dianhydride (6FDA).

[0011] The structure of the diamine single-photosensitive element is shown in formula (1):

[0012] (1)

[0013] In the formula, n = 1, 2, 3, 4 or 5;

[0014] S2, after cooling the polyamic acid (PAA) solution to 0~10 ℃, trifluoroacetic anhydride (TFAA) and triethylamine (TEA) are added, and the reaction is carried out at room temperature to synthesize the intermediate (PII). Then, N,N-dimethylformamide diethyl acetal (DFA) is added and reacted at 40~60 ℃ to synthesize the photosensitive polyimide polymer (PIAE).

[0015] As a further preferred technical solution of the present invention, in step (1), the molar ratio of dianhydride, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and diamine single photosensitive element is 10:9:1.

[0016] As a further preferred technical solution of the present invention, in step S1, the organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide (DMAc), N-methylpyrrolidone, dimethyl sulfoxide, propylene glycol methyl ether acetate and γ-butyrolactone.

[0017] As a further preferred technical solution of the present invention, the diamine photosensitive monomer is obtained by reacting a compound of the following formula (2) with 4-aminophenylboronic acid via a Suzuki coupling reaction;

[0018] (2)

[0019] In the formula, n = 1, 2, 3, 4 or 5.

[0020] As a further preferred technical solution of the present invention, the compound of structural formula (2) is obtained by the following steps:

[0021] (1) Starting with 5-hydroxy-2-nitrobenzaldehyde, the compound was reacted with methyl 3-aminocrotonate in an ice bath and under the catalysis of trifluoroacetic acid to prepare the compound of formula (3) as follows:

[0022] (3);

[0023] (2) Using dibromo-substituted straight-chain alkanes as starting materials, under alkaline conditions, the hydroxyl group of the compound of formula (3) undergoes a substitution reaction with the halogen group at one end of the dibromo-substituted straight-chain alkanes to obtain the compound of formula (4) as follows:

[0024] (4)

[0025] In the formula, n = 1, 2, 3, 4 or 5;

[0026] (3) Using 3,5-dibromophenol as the starting material, under alkaline conditions, the halogen group of the compound of formula (4) is subjected to a substitution reaction with the hydroxyl group of 3,5-dibromophenol to obtain the compound of formula (2).

[0027] According to another aspect of the present invention, the present invention also provides a photosensitive polyimide polymer prepared by the above preparation method.

[0028] According to another aspect of the present invention, the present invention also provides the application of a photosensitive polyimide polymer in the preparation of a photosensitive polyimide film.

[0029] According to another aspect of the present invention, a photosensitive polyimide film is also provided, which is prepared from the above-described photosensitive polyimide polymer.

[0030] The present invention also provides a method for preparing a photosensitive polyimide film, which includes the following steps:

[0031] (1) The photosensitive polyimide polymer is prepared into a solution and spin-coated onto the surface of a substrate to form a photosensitive wet film layer;

[0032] (2) The photosensitive wet film layer is soft-baked to form a photosensitive film;

[0033] (3) Expose the photosensitive film to ultraviolet light to form a cured film;

[0034] (4) The cured film is developed to obtain a photolithographic pattern, and then cured at 150-250 °C to obtain the photosensitive polyimide film.

[0035] As a further preferred technical solution of the present invention, the photosensitive polyimide polymer is first washed and dried, and then dissolved in 1-methoxy-2-propanol at a solid content of 10~20 wt% to prepare a solution;

[0036] And / or, the spin coating speed is 1000~1500 r / min;

[0037] And / or, the soft baking temperature is 80~100℃, and the time is 3~15 min;

[0038] And / or, the wavelength of the ultraviolet lamp is 365 nm, and the exposure dose for the exposure treatment is 150~250 mJ / cm. 2 ;

[0039] And / or, the cured film is developed in an alkaline developer, tetramethylammonium hydroxide.

[0040] Compared with the prior art, the present invention, by adopting the above technical solution, can achieve the following beneficial effects:

[0041] 1) The diamine photosensitive monomer compound used in this invention exhibits highly beneficial photoresponsiveness to ultraviolet light. Its fluorescence emission is altered by pyridine cyclization after ultraviolet irradiation, allowing it to be copolymerized into a photosensitive polyimide polymer grafted with ester units after isoimide pretreatment. This diamine photosensitive monomer compound exhibits good thermal stability, a simple preparation process, strong intermediate product stability, and low-toxicity and harmless post-treatment purification.

[0042] 2) The photosensitive polyimide prepared by this invention can achieve a polyimide pattern retention rate of over 98% and a sensitivity value of 246 mJ / cm. 2 The pattern resolution is 5μm, the light transmittance is above 93%, and the hydrophobicity is good. At the same time, the polyimide film has good mechanical properties and can be developed in alkaline solutions.

[0043] 3) In the preparation of photosensitive polyimide films, the present invention prepares customized patterns by exposure masks, which can then be applied to advanced packaging, 3D printing and flexible organic light-emitting diodes. Attached Figure Description

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0045] Figure 1 This is a schematic diagram of the synthesis of the diamine photosensitive monomer in this invention.

[0046] Figure 2 The NMR spectrum of the diamine photosensitive monomer DHPN prepared in Example 1 is shown.

[0047] Figure 3 This is a schematic diagram showing the structural changes of the diamine photosensitive monomer DHPN prepared in Example 1 before and after UV irradiation.

[0048] Figure 4 The NMR spectra of the diamine photosensitive monomer DHPN prepared in Example 1 before and after UV irradiation are compared.

[0049] Figure 5 The fluorescence emission spectra of the diamine photosensitive monomer DHPN prepared in Example 1 before and after UV irradiation are compared.

[0050] Figure 6 This is a schematic diagram of the synthesis of the photosensitive polyimide film of the present invention.

[0051] Figure 7 The transmittance is the photosensitive polyimide film prepared in Example 2.

[0052] Figure 8 Contact angle test of the photosensitive polyimide film prepared in Example 2.

[0053] Figure 9The photosensitivity curve of the photosensitive polyimide film prepared in Example 2 is shown.

[0054] Figure 10 The resolution of the photolithographic pattern of the photosensitive polyimide film prepared in Example 2.

[0055] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0056] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0057] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods. Example 1

[0058] This embodiment provides a method for preparing a diamine photosensitive monomer DHPN containing dihydropyridine with photosensitizing properties. Figure 1 Its synthesis technology roadmap (specifically includes the following steps performed sequentially):

[0059] (1) First, weigh 1.67 g (1 mmol, 1 eq) of 5-hydroxy-2-nitrobenzaldehyde and 3.45 g (3 mmol, 3 eq) of methyl 3-aminocrotonate. Measure 15 ml of anhydrous ethanol into a two-necked flask to dissolve 5-hydroxy-2-nitrobenzaldehyde and methyl 3-aminocrotonate, respectively. Specific operation: Dissolve 5-hydroxy-2-nitrobenzaldehyde. Add 27 ml (3.5 mmol, 3 eq) of trifluoroacetic acid to the anhydrous ethanol solution containing 5-hydroxy-2-nitrobenzaldehyde under ice bath. Then, gradually add 150 ml of anhydrous ethanol solution containing methyl 3-aminocrotonate under ice bath. React at 0 ℃ under ice bath and monitor the reaction progress with TCL. After the reaction is completed, add deionized water to precipitate, filter, and wash the filtrate rapidly with a large amount of dichloromethane. Filter to obtain the purified product P1.

[0060] P1;

[0061] (2) P1 (1 eq), K2CO3 (3 mmol), and acetone (70 mL) were added to separate flasks. The mixture was heated to 80 °C under an inert atmosphere and refluxed for 10 min. Then, 1,4-dibromobutane (3 eq) was injected into the solution, and the mixture was refluxed overnight. After cooling to room temperature, intermediate P2 was purified by petroleum ether / dichloromethane silica gel column chromatography. Intermediate P2 was a pale yellow crystalline powder (conversion rate 60%).

[0062] P2, where n=2;

[0063] (3) Intermediate P2 (1 eq), 3,5-dibromophenol (1.2 eq), and K2CO3 (3 eq) were dissolved in acetone (80 mL), and stirred overnight at 80 °C under an inert atmosphere. After the reaction was completed, intermediate P3 was purified by petroleum ether / dichloromethane silica gel column chromatography. Intermediate P3 was a pale yellow crystalline powder (yield 79%).

[0064] P3, where n=2;

[0065] (4) In a 500 mL flask, add intermediate P3 (1 eq), tetrahydrofuran (100 mL), and catalyst amount tetra(triphenylphosphine)palladium(0) (Pd[P(C6H5)3]4), then add 2M K2CO3 aqueous solution (70 mL) and 4-aminophenylboronic acid (2.5 eq). After removing air with an inert gas, stir and reflux the reaction mixture overnight under an inert gas atmosphere. After the reaction is complete, purify the product by petroleum ether / dichloromethane silica gel column chromatography, finally obtaining the diamine photosensitizer DHPN containing dihydropyridine. Its structure is determined by... 1 HNMR identification, such as Figure 2 .

[0066] This invention successfully introduces two primary amine (-NH2) groups at both ends of the molecule. Primary amines are extremely important and reactive functional groups in polymerization chemistry, capable of readily undergoing condensation or addition polymerization reactions with various monomers such as diacids, diacid anhydrides, diacid chlorides, epoxides, and isocyanates. This allows DHPN to be directly used as a core monomer unit for constructing high-performance photosensitive polyamic acid, polyimide, and polyisoimide, greatly expanding the application range of DHP materials.

[0067] The diamine photosensitizer DHPN, based on a dihydropyridine unit, exhibits ultraviolet light sensitivity. Under ultraviolet light irradiation, its structure undergoes an intramolecular dehydration reaction, thereby achieving its photosensitivity. The following are the photosensitivity test results for the diamine photosensitizer DHPN. Figure 3 , Figure 4 and Figure 5 :

[0068] like Figure 3 The diagram shown illustrates the structural changes of the DHPN before and after illumination.

[0069] like Figure 4 The image shows a comparison of NMR spectra before and after UV irradiation of DHPN. Analysis of the NMR spectra reveals the disappearance of the "H" at the low-field region (chemical shift 8.97 ppm) belonging to the 1,4-dihydropyridine ring structure, and the "H" at chemical shift 5.64 ppm. The "H" at chemical shift 5.28 ppm shifts to a higher field, and both "H"s disappear after irradiation, confirming the formation of the pyridine cyclization structure.

[0070] like Figure 5 Before and after UV irradiation, the liquid (ethanol) emission spectrum of the diamine photosensitive monomer DHPN showed that the maximum emission peak before UV was 445 nm and the maximum emission peak after UV was 496 nm, a redshift of 51 nm, which can further help explain the formation of the pyridine cyclization structure. Example 2

[0071] This embodiment describes a method for further preparing a photosensitive polyimide film based on the diamine photosensitive monomer DHPN from Example 1. The specific steps are as follows:

[0072] (1) Weigh out 10 mmol of dianhydride and dissolve it in N,N-dimethylacetamide (DMAc). Under nitrogen protection and at room temperature, slowly add 4,4'-(hexafluoroisopropene)phthalic anhydride (6FDA) (9 mmol) and DHPN (1 mmol) in portions. React for 5 h to obtain a polyamic acid (PAA) solution. Cool the polyamic acid (PAA) solution to 5 °C, add 4.26 mL of TFAA (30 mmol) and 4.26 mL of TEA (30 mmol) to the PAA solution to induce isoimide reaction of PAA. React at room temperature for 5 h to synthesize PII. Then add DFA (3.61 mL, 20 mmol) and react at 50 °C for 5 h to synthesize polyimide PIAE (see the synthesis technology circuit diagram). Figure 6 ).

[0073] (2) Pour the PIAE solution into deionized water to precipitate the solid, filter it, and wash it repeatedly with deionized water 3 times. Then dry it in a 50 ℃ oven in the dark for 24 h to obtain a light yellow solid powder. Then dissolve it in 1-methoxy-2-propanol at a solid content of 15 wt%. After complete dissolution, filter the obtained PIAE solution through a 0.22 μm polytetrafluoroethylene filter and store it for later use.

[0074] (3) Spin coat the filtered PIAE solution onto the surface at a speed of 1000 r / min. A photosensitive wet film layer is formed on the glass slide, and then it is soft-baked at 100℃ for 5 minutes to form a photosensitive film.

[0075] (4) After soft baking, the glass slide with the photosensitive film is exposed to a 365 nm wavelength ultraviolet lamp for mask exposure, with an exposure dose of 250.0 mJ / cm. 2 Then, the sample was developed in an alkaline developer, tetramethylammonium hydroxide (TMAH), to form a photolithographic pattern. After development, the sample was cured in a vacuum oven at 250 °C for 1 h to obtain a patterned photosensitive polyimide film. A square photomask with equal periods was used for mask exposure, with an exposed area width of 5 μm and an unexposed area width of 10 μm. The obtained photosensitive polyimide film was tested, and the results are as follows: Figure 7 , Figure 8 , Figure 9 and Figure 10 .

[0076] The photosensitive polyimide film obtained in Example 2 had a thickness of 5 micrometers, a film retention rate of 98.7% during the curing process, and a sensitivity of 246 mJ / cm. 2 The pattern resolution is 5 μm, the light transmittance is 93.6%, and the hydrophobicity is good. Example 3

[0077] The photosensitive polyimide film was prepared using a method that was essentially the same as in Example 2, except that the dianhydride 6FAP used to prepare polyamic acid (PAA) was replaced with an equimolar amount of 3,3,4,4-biphenyltetracarboxylic dianhydride (BTDA).

[0078] The photosensitive polyimide film obtained in Example 3 had a thickness of 5 micrometers, a film retention rate of 99% during the curing process, and a sensitivity of 246 mJ / cm. 2 The pattern resolution is 5 μm, the light transmittance is 93.8%, and the hydrophobicity is good.

[0079] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a photosensitive polyamic acid ester polymer, characterized in that, Includes the following steps: S1, under nitrogen protection, dianhydride is dissolved in an organic solvent, and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and diamine photosensitive monomer are added to react and obtain a polyamic acid solution; The dianhydride is selected from 3,3,4,4-biphenyltetracarboxylic dianhydride or 4,4'-(hexafluoroisopropene) dianhydride; The structure of the diamine photosensitive monomer is shown in formula (1): （1） In the formula, n = 1, 2, 3, 4 or 5; S2, after cooling the polyamic acid solution to 0~10 ℃, trifluoroacetic anhydride and triethylamine are added, and the intermediate is synthesized by reacting at room temperature. Then, N,N-dimethylformamide diethyl acetal is added and reacted at 40~60 ℃ to synthesize the photosensitive polyamic acid ester polymer.

2. The method for preparing the photosensitive polyaminate polymer according to claim 1, characterized in that, In step (1), the molar ratio of dianhydride, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and diamine monophotosensitive element is 10:9:

1.

3. The method for preparing the photosensitive polyaminate polymer according to claim 1, characterized in that, In step S1, the organic solvent is at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, propylene glycol methyl ether acetate, and γ-butyrolactone.

4. The method for preparing the photosensitive polyaminate polymer according to claim 1, characterized in that, The diamine photosensitive monomer is obtained by a Suzuki coupling reaction between a compound with the structure shown in formula (2) and 4-aminophenylboronic acid; （2） In the formula, n = 1, 2, 3, 4 or 5.

5. The method for preparing the photosensitive polyaminate polymer according to claim 4, characterized in that, The compound of formula (2) is prepared by the following steps: (1) Starting with 5-hydroxy-2-nitrobenzaldehyde, the compound with the structure shown in formula (3) was prepared by reacting it with methyl 3-aminocrotonate in an ice bath and under the catalysis of trifluoroacetic acid: （3）； (2) Using dibromo-substituted straight-chain alkanes as starting materials, under alkaline conditions, the hydroxyl group of the compound of formula (3) undergoes a substitution reaction with the halogen group at one end of the dibromo-substituted straight-chain alkanes to obtain a compound with the structure shown in formula (4): （4） In the formula, n = 1, 2, 3, 4 or 5; (3) Using 3,5-dibromophenol as the starting material, under alkaline conditions, the halogen group of the compound of formula (4) is subjected to a substitution reaction with the hydroxyl group of 3,5-dibromophenol to obtain the compound of formula (2).

6. The photosensitive polyaminate polymer prepared by the preparation method according to any one of claims 1-5.

7. The use of the photosensitive polyaminate polymer of claim 6 in the preparation of photosensitive polyimide films.

8. A photosensitive polyimide film, characterized in that, It is prepared from the photosensitive polyamic acid ester polymer of claim 6.

9. A method for preparing the photosensitive polyimide film according to claim 8, characterized in that, Includes the following steps: (1) The photosensitive polyamic acid ester polymer is prepared into a solution and spin-coated onto the surface of a substrate to obtain a photosensitive wet film layer; (2) The photosensitive wet film layer is soft-baked to obtain a photosensitive film; (3) Expose the photosensitive film under an ultraviolet lamp to obtain a cured film; (4) The cured film is developed to obtain a photolithographic pattern, and then cured at 150-250 °C to obtain the photosensitive polyimide film.

10. The method for preparing the photosensitive polyimide film according to claim 9, characterized in that, The photosensitive polyamic acid ester polymer is first washed and dried, and then dissolved in 1-methoxy-2-propanol at a solid content of 10~20 wt% to prepare a solution; And / or, the spin coating speed is 1000~1500 r / min; And / or, the soft baking temperature is 80~100℃, and the time is 3~15 min; And / or, the wavelength of the ultraviolet lamp is 365 nm, and the exposure dose for the exposure treatment is 150~250 mJ / cm. 2 ; And / or, the cured film is developed in an alkaline developer, tetramethylammonium hydroxide.

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