Photosensitive polyimide polymer, photosensitive polyimide film and preparation method and application thereof

Abstract

The invention relates to the technical field of photosensitive resin materials, in particular to a photosensitive polyimide polymer, a photosensitive polyimide film and a preparation method and application of the photosensitive polyimide polymer and the photosensitive polyimide film. The preparation method comprises the following steps: reacting 1, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane and a diamine photosensitive monomer to obtain a polyamide acid solution; cooling the polyamide acid solution to 0-10 DEG C, adding TFAA and TEA, reacting and synthesizing at room temperature to obtain an intermediate, then adding DFA, reacting at 40-60 DEG C, and synthesizing to obtain the photosensitive polyimide polymer. The diamine photosensitive monomer compound adopted by the invention has very beneficial photoresponsiveness to ultraviolet light, pyridine cyclization is utilized to change fluorescence emission of the diamine photosensitive monomer compound after ultraviolet irradiation, and the diamine photosensitive monomer compound can be copolymerized to a photosensitive polyimide polymer grafted with an ester unit after isoimidization pretreatment.

Description

Technical Field

[0001] The present invention relates to the technical field of photosensitive resin materials, and in particular to a photosensitive polyimide polymer, a photosensitive polyimide film, and a preparation method and application thereof. Background Art

[0002] High-performance plastics have attracted considerable attention due to their potential applications in the aerospace, automotive, electronics, and related industries. Polyimides, in particular, are widely used as insulating materials in microelectronic devices due to their excellent properties, such as thermal and chemical stability and a low dielectric constant. They are generally prepared by reacting aromatic dianhydrides with aromatic diamines. This reaction proceeds through a soluble polyamic acid intermediate, which undergoes condensation upon further heating to form polyimide 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 desired form, and then thermally cyclized to form the polyimide. However, this processing method, using polyamic acid (PAA) as a precursor, has some significant limitations. For example, the photosensitive polyamic acid system composed of PAA and naphthoquinone diazide sulfonate is difficult to achieve a large solubility difference between exposed and unexposed areas, making it insufficient for constructing fine patterns. As well as technical barriers such as the generally high thermal imidization temperature and the excessively large thermal expansion coefficient, in order to improve the sensitivity and resolution (minimum exposure width) of the photolithography process, controlling the dissolution rate of PAA in alkaline solution is an important topic that needs to be studied.

[0003] Esterification and hydrophobic treatment of PAA is one of the most common methods, but the degree of esterification of direct esterification is low and the dissolution rate is still fast. Since polyisoimide has excellent processing properties and is easily converted into polyimide, it is considered to be one of the ideal photosensitive polyimide precursors. 1,4-Dihydropyridine (DHP) and its derivatives have become ideal modules for constructing photoresponsive materials due to their unique photochemical reactivity. Under light, the DHP ring can undergo a controllable oxidative dehydrogenation reaction to transform 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 the polymer system to prepare high-performance photosensitive materials, the synthesis method of the photosensitive monomer in the existing technology has many disadvantages, as follows: 1) Complex synthetic routes and low yields: Existing monomers containing DHP functional groups, particularly those with multiple reactive groups, often require lengthy and cumbersome synthetic routes. The cumulative yields of these multi-step reactions are typically low, significantly increasing production costs and limiting their scalable application. For example, some methods require demanding reaction conditions, such as ultra-low temperatures or anhydrous and oxygen-free environments, placing high demands on equipment and operation, and exhibiting numerous side reactions, making isolation and purification of the target product difficult.

[0004] 2) Poor structural tunability: Many existing synthetic methods are highly rigid, making it difficult to adjust the monomer's molecular structure by simply changing the starting materials. For example, these methods can alter the substituents on the central photosensitive core, adjust the length or flexibility of the linker arms, or change the type of terminal functional groups. This difficulty in customized synthesis hinders the systematic optimization of the monomer's optoelectronic properties and polymerization reactivity.

[0005] 3) Stability issues: Some DHP derivatives are sensitive to light, heat or acidic environments, and are prone to decomposition or unexpected side reactions during the synthesis or purification process, resulting in low product purity, low yield, and inconvenient storage and use. Summary of the Invention

[0006] In view of this, the present invention provides a photosensitive polyimide polymer, a photosensitive polyimide film, and a preparation method and application thereof, in order to solve the technical barriers of the prior art such as generally too high thermal imidization temperature and too large thermal expansion coefficient, and the technical problem that the sensitivity and resolution of the photolithography process need to be improved. The present invention pre-treats the polyamic acid (PAA) precursor with isoimidation and then grafts ester groups, thereby improving the degree of esterification reaction, achieving a low thermal imidization temperature (less than 200°C) and a low thermal expansion coefficient (26 ppm K -1 ) and an exposure sensitivity of 246mJ / cm 2 And the resolution is 5μm excellent technical effect.

[0007] To achieve the above object, the present invention provides a method for synthesizing a novel photosensitive monomer of a diamine containing dihydropyridine, which comprises the following steps: S1, under nitrogen protection, dissolving the dianhydride in an organic solvent, and slowly adding diamine 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP) and a diamine single photosensitive body in batches to react to obtain a polyamic acid (PAA) solution; The dianhydride is selected from 3,3,4,4-biphenyltetracarboxylic dianhydride (BTDA) or 4,4'-(hexafluoroisopropylene) diphthalic anhydride (6FDA); The structure of the diamine single photosensitive body is shown in the following formula (1): (1) Where n=1, 2, 3, 4 or 5; S2: After the polyamic acid (PAA) solution is cooled to 0-10°C, trifluoroacetic anhydride (TFAA) and triethylamine (TEA) are added, and then reacted at room temperature to synthesize the intermediate (PII). Subsequently, N,N-dimethylformamide diethyl acetal (DFA) is added and reacted at 40-60°C to synthesize the photosensitive polyimide polymer (PIAE).

[0008] 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 body is 10:9:1.

[0009] 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.

[0010] As a further preferred technical solution of the present invention, the diamine photosensitive monomer is obtained by Suzuki coupling reaction of a compound of the following formula (2) with 4-aminophenylboronic acid; (2) Where n=1, 2, 3, 4 or 5.

[0011] As a further preferred technical solution of the present invention, the compound of structural formula (2) is prepared by the following steps: (1) 5-Hydroxy-2-nitrobenzaldehyde is used as the starting material and reacted with methyl 3-aminocrotonate in an ice bath under the catalysis of trifluoroacetic acid to obtain the compound of the following formula (3): (3); (2) Using dibromo straight-chain alkane as a starting material, under alkaline conditions, the hydroxyl group of the compound of formula (3) is subjected to a substitution reaction with the halogen group at one end of the dibromo straight-chain alkane to obtain a compound of formula (4): (4) Where n=1, 2, 3, 4 or 5; (3) Using 3,5-dibromophenol as a starting material, the halogen group of the compound of formula (4) is subjected to a substitution reaction with the hydroxyl group of 3,5-dibromophenol under alkaline conditions to prepare the compound of formula (2).

[0012] According to another aspect of the present invention, the present invention also provides a photosensitive polyimide polymer prepared by the above preparation method.

[0013] According to another aspect of the present invention, the present invention also provides a use of a photosensitive polyimide polymer in preparing a photosensitive polyimide film.

[0014] According to another aspect of the present invention, the present invention further provides a photosensitive polyimide film, which is prepared from the above-mentioned photosensitive polyimide polymer.

[0015] The present invention also provides a method for preparing a photosensitive polyimide film, which comprises the following steps: (1) preparing a solution of the photosensitive polyimide polymer and spin-coating the solution on the surface of the substrate to form a photosensitive wet film layer; (2) soft-baking the photosensitive wet film layer to form a photosensitive film; (3) exposing the photosensitive film to ultraviolet light to form a cured film; (4) Developing the cured film to obtain a photolithographic pattern, and then curing the cured film at 150-250° C. to obtain the photosensitive polyimide film.

[0016] 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; and / or, the spin coating speed is 1000-1500 r / min; and / or, soft baking at a temperature of 80-100°C for 3-15 minutes; And / or, the wavelength of the UV lamp is 365 nm, and the exposure dose of the exposure treatment is 150~250 mJ / cm 2 ; And / or, the cured film is developed in an alkaline developer, tetramethylammonium hydroxide.

[0017] Compared with the prior art, the present invention adopts the above technical solution to achieve the following beneficial effects: 1) The diamine photosensitive monomer compound employed in this invention exhibits highly beneficial photoresponsiveness to ultraviolet light. Upon exposure to ultraviolet light, the compound undergoes pyridine cyclization, thereby altering its fluorescence emission. This compound can then be copolymerized into a photosensitive polyimide polymer with grafted ester units after isoimidization pretreatment. This diamine photosensitive monomer compound exhibits excellent thermal stability, a simple preparation process, highly stable intermediate products, and low toxicity and harmlessness after post-processing and purification.

[0018] 2) The photosensitive polyimide prepared by the present invention can make the film retention rate of the polyimide pattern above 98% and the sensitivity value at 246mJ / cm 2 The pattern resolution is 5 μm, the 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 an alkaline solution.

[0019] 3) In the preparation of photosensitive polyimide film, the present invention prepares customized patterns by exposing masks, thereby being applied in advanced packaging, 3D printing and flexible organic light-emitting diodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Figure 1 The synthetic route diagram of the diamine photosensitive monomer in the present invention is shown in FIG.

[0022] Figure 2 This is the NMR spectrum of the diamine photosensitive monomer DHPN prepared in Example 1.

[0023] Figure 3 Schematic diagram of the structural changes of the diamine photosensitive monomer DHPN prepared in Example 1 before and after UV irradiation.

[0024] Figure 4 This is a comparison of the NMR spectra of the diamine photosensitive monomer DHPN prepared in Example 1 before and after UV irradiation.

[0025] Figure 5 This is a comparison of the fluorescence emission spectra of the diamine photosensitive monomer DHPN prepared in Example 1 before and after UV irradiation.

[0026] Figure 6 This is a synthetic route diagram for the photosensitive polyimide film of the present invention.

[0027] Figure 7 is the transmittance of the photosensitive polyimide film prepared in Example 2.

[0028] Figure 8 This is the contact angle test of the photosensitive polyimide film prepared in Example 2.

[0029] Figure 9 This is the photosensitivity curve of the photosensitive polyimide film prepared in Example 2.

[0030] Figure 10 The photolithographic pattern resolution of the photosensitive polyimide film prepared in Example 2.

[0031] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0032] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0033] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; the experimental methods described, unless otherwise specified, are conventional methods. Example 1

[0034] This embodiment provides a method for preparing a diamine photosensitive monomer DHPN containing dihydropyridine having photosensitivity ( Figure 1 The synthesis technology roadmap includes the following steps: (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, and add 15 ml of anhydrous ethanol into two flasks 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 anhydrous ethanol solution containing methyl 3-aminocrotonate (150 ml) under ice bath, react under ice bath at 0 °C, and monitor the reaction progress by TLC. After the reaction is completed, add deionized water for precipitation, filter, and quickly wash the intercepted product with a large amount of dichloromethane and filter to obtain the purified product P1.

[0035] P1; (2) P1 (1 eq), K2CO3 (3 mmol), and acetone (70 mL) were added to a flask, heated to 80 °C under an inert atmosphere, and maintained at reflux for 10 min. 1,4-Dibromobutane (3 eq) was then injected into the solution, and refluxed overnight. After cooling to room temperature, the intermediate P2 was purified by petroleum ether / dichloromethane silica gel column chromatography. Intermediate P2 was obtained as a light yellow crystalline powder (conversion rate 60%).

[0036] P2, where n = 2; (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 gas atmosphere. After the reaction, intermediate P3 was purified by petroleum ether / dichloromethane silica gel column chromatography. Intermediate P3 was obtained as a light yellow crystalline powder (yield 79%).

[0037] P3, where n = 2; (4) In a 500 mL flask, intermediate P3 (1 eq), tetrahydrofuran (100 mL) and a catalytic amount of tetrakis(triphenylphosphine)palladium(0) (Pd [P(C6H5)3]4) were added, followed by the addition of 2M K2CO3 aqueous solution (70 mL) and 4-aminophenylboronic acid (2.5 eq). After removing the air with an inert gas, the reaction mixture was stirred and refluxed under an inert gas overnight. After the reaction was completed, the product was purified by petroleum ether / dichloromethane silica gel column chromatography to obtain a diamine photosensitive monomer DHPN containing dihydropyridine, the structure of which was described by1 HNMR identification, such as Figure 2 .

[0038] This invention successfully introduces two primary amine (-NH2) groups at either end of the molecule. Primary amines are extremely important and active functional groups in polymerization chemistry, readily reacting with a variety of monomers, including diacids, dianhydrides, diacid chlorides, epoxides, and isocyanates, to form DHPN. This allows DHPN to be directly used as a core monomer unit in the construction of high-performance photosensitive polyamic acids, polyimides, and polyisoimides, greatly expanding the application range of DHP materials.

[0039] The diamine photosensitive monomer DHPN is based on the dihydropyridine unit and is sensitive to ultraviolet light. Under ultraviolet light, its structure can undergo intramolecular dehydration reaction, thereby achieving its photosensitivity. The following is a test of the photosensitivity of the diamine photosensitive monomer DHPN. The results are as follows: Figure 3 、 Figure 4 and Figure 5 : like Figure 3 Figure 2 shows the schematic diagram of the structural changes of DHPN before and after illumination.

[0040] like Figure 4 The following figure shows a comparison of the NMR spectra of DHPN before and after UV illumination. Analysis of the NMR spectra reveals the disappearance of the "H" at the downfield portion (chemical shift of 8.97 ppm) attributed to the 1,4-dihydropyridine ring structure, as well as the "H" at the chemical shift of 5.64 ppm. The chemical shift at 5.28 ppm shifts upfield, and both "H"s disappear after illumination, confirming the formation of a pyridine ring structure.

[0041] 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, with a red shift of 51 nm, which can further assist in explaining the formation of the pyridine cyclization structure. Example 2

[0042] This embodiment is a method for further preparing a photosensitive polyimide film based on the diamine photosensitive monomer DHPN in Example 1. The specific steps are as follows: (1) Weigh and dissolve dianhydride (10 mmol) in N,N-dimethylacetamide (DMAc). Under nitrogen protection and room temperature, slowly add two diamine monomers, 4,4'-(hexafluoroisopropylene) diphthalic anhydride (6FDA) (9 mmol) and DHPN (1 mmol) in batches and react for 5 h to obtain a polyamic acid (PAA) solution. Cool the polyamic acid (PAA) solution to 5 °C, add TFAA (4.26 mL, 30 mmol) and TEA (4.26 mL, 30 mmol) to the PAA solution to cause isoimidization of PAA. The reaction is carried out at room temperature for 5 h to synthesize PII. Subsequently, DFA (3.61 mL, 20 mmol) is added and the reaction is carried out at 50 °C for 5 h to synthesize polyimide PIAE (see the synthesis technology route diagram). Figure 6 ).

[0043] (2) The PIAE solution was poured into deionized water to precipitate the solid, which was filtered and washed repeatedly with deionized water three times. The solid was then dried in a 50 °C oven in the dark for 24 h to obtain a light yellow solid powder. The powder was then dissolved in 1-methoxy-2-propanol at a solid content of 15 wt%. After complete dissolution, the obtained PIAE solution was filtered through a 0.22 μm polytetrafluoroethylene filter and stored for later use.

[0044] (3) Spin-coat the filtered PIAE solution at a speed of 1000 r / min onto A photosensitive wet film layer was formed on the glass sheet, and then soft-baked at 100 °C for 5 min to form a photosensitive film.

[0045] (4) After soft baking, the glass sheet with the photosensitive film was placed under a 365 nm wavelength UV lamp and exposed with a mask at an exposure dose of 250.0 mJ / cm 2 ; Then, it 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 hour to obtain a patterned photosensitive polyimide film. The mask exposure used a square photomask with an equal period, and the width of the exposed area was 5 μm, and the width of the unexposed area was 10 μm. The obtained photosensitive polyimide film was tested: the results are as follows: Figure 7 、 Figure 8 、 Figure 9 and Figure 10 .

[0046] The photosensitive polyimide film obtained in Example 2 was tested to have a thickness of 5 μm, 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 transmittance is 93.6%, and the hydrophobicity is good. Example 3

[0047] A photosensitive polyimide film was prepared using a method substantially the same as that in Example 2, except that the dianhydride 6FAP used to prepare polyamic acid (PAA) was replaced with an equal molar amount of 3,3,4,4-biphenyltetracarboxylic dianhydride (BTDA).

[0048] The photosensitive polyimide film obtained in Example 3 was tested to have a thickness of 5 μm, 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 transmittance is 93.8%, and the hydrophobicity is good.

[0049] Although specific embodiments of the present invention are described above, those skilled in the art should understand that these are merely examples and that various changes or modifications may be made to the embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a photosensitive polyimide polymer, characterized in that: The following steps are involved: S1, under nitrogen protection, dissolving dianhydride in an organic solvent, and adding 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and a diamine photosensitive monomer to react to obtain a polyamic acid solution; The dianhydride is selected from 3,3,4,4-biphenyltetracarboxylic dianhydride or 4,4'-(hexafluoroisopropylene) diphthalic anhydride; The structure of the diamine photosensitive monomer is shown in the following formula (1): （1） Where n=1, 2, 3, 4 or 5; S2, after cooling the polyamic acid solution to 0-10°C, trifluoroacetic anhydride and triethylamine are added, and then reacted at room temperature to synthesize an intermediate, and then N,N-dimethylformamide diethyl acetal is added to react at 40-60°C to synthesize a photosensitive polyimide polymer.

2. The method for preparing a photosensitive polyimide polymer according to claim 1, wherein: In step (1), the molar ratio of dianhydride, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and diamine single photosensitive body is 10:9:

1.

3. The method for preparing a photosensitive polyimide polymer according to claim 1, wherein: 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 a photosensitive polyimide polymer according to claim 1, wherein: The diamine photosensitive monomer is obtained by Suzuki coupling reaction of a compound having a structure shown in the following formula (2) with 4-aminophenylboronic acid; （2） Where n=1, 2, 3, 4 or 5.

5. The method for preparing a photosensitive polyimide polymer according to claim 4, wherein: The compound of formula (2) is prepared by the following steps: (1) 5-Hydroxy-2-nitrobenzaldehyde was used as the starting material and reacted with methyl 3-aminocrotonate in an ice bath under the catalysis of trifluoroacetic acid to obtain a compound having the structure shown in the following formula (3): （3）； (2) Using dibromo straight-chain alkane as a starting material, under alkaline conditions, the hydroxyl group of the compound of formula (3) is subjected to a substitution reaction with the halogen group at one end of the dibromo straight-chain alkane to prepare a compound having the structure shown in the following formula (4): （4） Where n=1, 2, 3, 4 or 5; (3) Using 3,5-dibromophenol as a starting material, the halogen group of the compound of formula (4) is subjected to a substitution reaction with the hydroxyl group of 3,5-dibromophenol under alkaline conditions to prepare the compound of formula (2).

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

7. Use of the photosensitive polyimide polymer according to claim 6 in the preparation of a photosensitive polyimide film.

8. A photosensitive polyimide film, characterized in that: Prepared from the photosensitive polyimide polymer according to claim 6.

9. A method for preparing the photosensitive polyimide film according to claim 8, characterized in that: The following steps are involved: (1) preparing a solution of the photosensitive polyimide polymer and spin-coating the solution on the surface of the substrate to obtain a photosensitive wet film layer; (2) soft-baking the photosensitive wet film layer to obtain a photosensitive film; (3) exposing the photosensitive film to ultraviolet light to obtain a cured film; (4) Developing the cured film to obtain a photolithographic pattern, and then curing the film at 150-250° C. to obtain the photosensitive polyimide film.

10. The method for preparing a photosensitive polyimide film according to claim 9, wherein: 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; and / or, the spin coating speed is 1000-1500 r / min; and / or, soft baking at a temperature of 80-100°C for 3-15 minutes; And / or, the wavelength of the UV lamp is 365 nm, and the exposure dose of 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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