Non-photosensitive polyimide film and preparation method thereof

Abstract

The invention provides a non-photosensitive polyimide film and a preparation method thereof, and relates to the technical field of high polymer materials. The preparation method of the non-photosensitive polyimide film comprises the following steps: mixing a diamine monomer not containing a carboxylic acid structure, a diamine monomer containing a carboxylic acid structure, a polar aprotic solvent and a tetracarboxylic dianhydride monomer, and carrying out a polymerization reaction to obtain a polyamide acid solution; and mixing the polyamide acid solution with a polar aprotic solvent to obtain a polyimide film precursor solution, and sequentially coating and drying the polyimide film precursor solution to obtain the non-photosensitive polyimide film. The non-photosensitive polyimide film is wide in developing window and good in film thickness uniformity, the developing window and the film thickness uniformity are improved by introducing a monomer structure of a carboxylic acid structure, and meanwhile excellent heat resistance, electrical insulation and mechanical resistance are kept.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a non-photosensitive polyimide film and a preparation method thereof. Background Art

[0002] Polyimide is a kind of polymer material with excellent heat resistance, chemical stability, excellent mechanical properties and electrical properties containing imide rings in the main chain, and has been widely used in the fields of microelectronics industry, advanced liquid crystal display technology, integrated circuits and the like.

[0003] The non-photosensitive polyimide material has excellent high and low temperature resistance, electrical insulation, adhesiveness, radiation resistance and medium resistance, and is widely used in semiconductor manufacturing packaging, coating and adhesive materials to form a protective film for devices or as an interlayer insulating layer for multi-layer wiring.

[0004] In the chip manufacturing process, the film thickness uniformity and defect control of the non-photosensitive polyimide material directly affect the yield and performance of the chip. Therefore, it is crucial to improve the film thickness uniformity and reduce the defects after development. In the spin coating and development process of polyimide, due to its high viscosity characteristics, there are problems of poor intra-wafer uniformity and edge residue after development. Therefore, how to disclose a non-photosensitive polyimide film that can maintain good film thickness uniformity under various thickness conditions and has a wide development window is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a non-photosensitive polyimide film and a preparation method thereof to solve the problem that the uniformity of the existing non-photosensitive polyimide material becomes worse as the film thickness increases during the film formation process, and the resulting poor chip performance.

[0006] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of a non-photosensitive polyimide film, comprising the following steps:

[0008] 1) Mixing a diamine monomer without a carboxylic acid structure, a diamine monomer with a carboxylic acid structure, a polar aprotic solvent and a tetracarboxylic dianhydride monomer to carry out a polymerization reaction to obtain a polyamic acid solution;

[0009] 2) Mixing the polyamic acid solution obtained in step 1) with a polar aprotic solvent to obtain a polyimide film precursor solution, and sequentially coating and drying the polyimide film precursor solution to obtain a non-photosensitive polyimide film.

[0010] Preferably, the structural formula of the diamine monomer with a carboxylic acid structure is shown in Formula I or Formula II:

[0011]

[0012] B in Formula I and Formula II 1 independently is an alkyl chain, or one or more of the following, wherein the general structural formula of the alkyl chain is C m H 2m , and m is any integer between 0 and 20;

[0013] B in Formula II 2 is selected from -COOH or -H, and the number of -COOH is 1 to 2.

[0014] Preferably, the structural formula of the diamine monomer without carboxylic acid structure is shown in Formula III or Formula IV:

[0015]

[0016] A in Formula III is an alkyl chain, -O-, -NH-, -S-, -SO 2 -, -COO-, -OCH 2 -, -CH 2 OCO, -CH 2 OCO-, -CH 2 O-, -NHCO-, -CONH-, -N(CH 3 )CO-, an olefin chain, an alkyne chain, a benzene ring, a cyclohexane, an imide ring, or one or more of them, wherein the general structural formula of the alkyl chain is C z H 2z , and z is any integer between 0 and 20;

[0017] R in Formula III and Formula IV independently is selected from -H, -CH 3 or one or more of them.

[0018] Preferably, the polar aprotic solvents described in step 1) and step 2) independently include one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, m-cresol, and tetrahydrofuran.

[0019] Preferably, the structure of the tetracarboxylic dianhydride monomer is shown in Formula V:

[0020]

[0021] G in Formula V 1 is an aliphatic, cycloaliphatic or aromatic organic group.

[0022] Preferably, the addition ratios of the diamine monomer without carboxylic acid structure, the diamine monomer with carboxylic acid structure, the polar aprotic solvent, and the tetracarboxylic dianhydride monomer are 0.03 - 0.08 mol : 0.03 - 0.08 mol : 100 - 120 g : 0.08 - 0.2 mol;

[0023] The temperature of the polymerization reaction is -15 - 100 °C, and the time is 1 - 24 h.

[0024] Preferably, the solid content of the polyamic acid in the polyimide film precursor solution is 1 - 40%.

[0025] Preferably, the drying temperature is 50 - 500 °C, and the drying time is 0.5 - 8 h.

[0026] Preferably, the thickness of the non-photosensitive polyimide film is 1 - 50 μm.

[0027] The present invention also provides a non-photosensitive polyimide film prepared by the above preparation method.

[0028] The present invention has at least the following beneficial effects:

[0029] The non-photosensitive polyimide film prepared by the present invention has the advantages of a wide development window and good film thickness uniformity. By introducing a monomer structure with a carboxylic acid structure, the development window and film thickness uniformity are improved, while excellent heat resistance, electrical insulation, and mechanical properties are maintained. Specific Embodiments

[0030] The present invention provides a method for preparing a non-photosensitive polyimide film, comprising the following steps:

[0031] 1) Mix a diamine monomer without carboxylic acid structure, a diamine monomer with carboxylic acid structure, a polar aprotic solvent, and a tetracarboxylic dianhydride monomer to carry out a polymerization reaction to obtain a polyamic acid solution;

[0032] 2) Mix the polyamic acid solution obtained in step 1) with a polar aprotic solvent to obtain a polyimide film precursor solution, and sequentially coat and dry the polyimide film precursor solution to obtain a non-photosensitive polyimide film.

[0033] In the present invention, the structural formula of the diamine monomer with carboxylic acid structure is shown in Formula I or Formula II:

[0034]

[0035] B in Formula I and Formula II 1 independently is an alkyl chain, one or several of, wherein the general structural formula of the alkyl chain is C m H2m where m is any integer between 0 and 20, specifically it can be 0, 1, 5, 8, 10, 12, 15, 18, 20;

[0036] B in formula II 2 is selected from -COOH or -H, and the number of -COOH is 1 to 2.

[0037] In the present invention, the diamine monomer containing a carboxylic acid structure includes and / or

[0038]

[0039] In the present invention, the structural formula of the diamine monomer without a carboxylic acid structure is shown in formula III or formula IV:

[0040]

[0041] A in formula III is an alkyl chain, -O-, -NH-, -S-, -SO 2 -, -COO-, -OCH 2 -, -CH 2 OCO, -CH 2 OCO-, -CH 2 O-, -NHCO-, -CONH-, -N(CH 3 )CO-, an olefin chain, an alkyne chain, a benzene ring, a cyclohexane, an imide ring, or one or more of them;

[0042] R in formula III and formula IV is independently selected from -H, -CH 3 or one or more of them;

[0043] Among them, the general formula of the alkyl chain structure is C z H 2z , where z is any integer between 0 and 20, specifically it can be 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20.

[0044] In the present invention, the diamine monomer without a carboxylic acid structure can be selected as

[0045]

[0046] In the present invention, the polar aprotic solvents in step 1) and step 2) independently include one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, m-cresol, and tetrahydrofuran.

[0047] In the present invention, the structure of the tetracarboxylic dianhydride monomer is shown in formula V:

[0048]

[0049] G in Formula V 1 is an aliphatic, alicyclic or aromatic organic group.

[0050] In the present invention, the tetracarboxylic dianhydride monomer can be selected from one or more of Formulae G-1 to G-24:

[0051]

[0052]

[0053]

[0054] In the present invention, the addition ratios of the diamine monomer without carboxylic acid structure, the diamine monomer with carboxylic acid structure, the polar aprotic solvent and the tetracarboxylic dianhydride monomer are 0.03 - 0.08 mol: 0.03 - 0.08 mol: 100 - 120 g: 0.08 - 0.2 mol, preferably 0.04 - 0.06 mol: 0.04 - 0.06 mol: 105 - 110 g: 0.1 - 0.15 mol, and more preferably 0.05 mol: 0.05 mol: 107.6 g: 0.1 mol.

[0055] In the present invention, the temperature of the polymerization reaction is -15 to 100 °C, preferably 0 to 90 °C, more preferably 20 to 80 °C, and even more preferably 50 to 70 °C; the time of the polymerization reaction is 1 to 24 h, preferably 4 to 20 h, more preferably 8 to 15 h, and even more preferably 10 to 13 h.

[0056] In the present invention, the polymerization reaction is carried out under an inert gas atmosphere.

[0057] In the present invention, the solid content of the polyamic acid in the polyimide film precursor solution is 1 - 40%.

[0058] In the present invention, the temperature of drying is 50 to 500 °C, and the time of drying is 0.5 to 8 h; preferably, gradient drying is adopted for drying, and the gradient drying procedure is as follows: drying at 80 - 120 °C for 1 hour, drying at 150 °C for 30 minutes, drying at 200 °C for 30 minutes, drying at 250 °C for 30 minutes, drying at 300 °C for 30 minutes, drying at 350 °C for 30 minutes, drying at 400 °C for 30 minutes, and drying at 450 °C for 30 minutes.

[0059] In the present invention, the thickness of the non-photosensitive polyimide film is 1 - 50 μm, preferably 5 - 45 μm, more preferably 10 - 40 μm, and even more preferably 15 - 35 μm.

[0060] The present invention also provides a non-photosensitive polyimide film prepared by the above preparation method.

[0061] The technical solutions provided by the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0062] Example 1

[0063] In a room temperature environment and under a nitrogen atmosphere, 5.4 g (0.05 mol) of p-phenylenediamine (denoted as compound DA-1), 7.6 g (0.05 mol) of 3,5-diaminobenzoic acid (denoted as compound DA-3) and 81.2 g of NMP (N-methyl-2-pyrrolidone) were added, and stirred at room temperature for 30 minutes to confirm complete dissolution. Then, 21.8 g (0.1 mol) of pyromellitic dianhydride (denoted as compound DN-1) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0064] Further, 232.0 g of NMP was added, and stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer, and then dried into a film in a circulating oven. The drying procedure was drying at 80-120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0065] Example 2

[0066] In a room temperature environment and under a nitrogen atmosphere, 5.4 g (0.05 mol) of p-phenylenediamine (DA-1), 7.6 g (0.05 mol) of 3,5-diaminobenzoic acid (DA-3) and 98.9 g of NMP were added, and stirred at room temperature for 30 minutes to confirm complete dissolution. Then, 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (denoted as compound DN-2) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0067] Add 282.7 g of NMP further, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0068] Example 3

[0069] In a room temperature environment and under a nitrogen atmosphere, add 4,4"-diaminodiphenyl ether (denoted as compound DA-2) 10.0 g (0.05 mol), 7.6 g (0.05 mol) of 3,5-diaminobenzoic acid (DA-3), and 91.9 g of NMP. Stir at room temperature for 30 minutes to confirm complete dissolution. Then add 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1), and stir at room temperature for 4 hours for a polymerization reaction to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0070] Add 262.7 g of NMP further, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0071] Example 4

[0072] In a room temperature environment and under a nitrogen atmosphere, add 20.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 7.6 g (0.05 mol) of 3,5-diaminobenzoic acid (DA-3), and 109.7 g of NMP. Stir at room temperature for 30 minutes to confirm complete dissolution. Then add 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2), and stir at room temperature for 4 hours for a polymerization reaction to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0073] Add 313.3 g of NMP further, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0074] Example 5

[0075] In a room temperature environment and under a nitrogen atmosphere, add 5.4 g (0.05 mol) of p-phenylenediamine (DA-1), 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid (denoted as compound DA-4) 14.305 g (0.05 mol) and 96.8 g of NMP, stir at room temperature for 30 minutes to confirm complete dissolution. Then add 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1), and stir at room temperature for 4 hours for a polymerization reaction to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0076] Add 276.7 g of NMP further, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0077] Example 6

[0078] Under a nitrogen atmosphere at room temperature, 5.4 g (0.05 mol) of p-phenylenediamine (DA-1), 14.305 g (0.05 mol) of 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid (DA-4) and 114.6 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then, 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0079] Further, 327.4 g of NMP was added, and stirring was carried out at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0080] Example 7

[0081] Under a nitrogen atmosphere at room temperature, 10.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 14.305 (0.05 mol) of 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid (DA-4) and 107.6 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then, 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0082] Further, 307.4 g of NMP was added, and stirring was carried out at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0083] Example 8

[0084] At room temperature under a nitrogen atmosphere, 20.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 14.305 g (0.05 mol) of 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid (DA-4) and 125.3 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0085] Further add 358.0 g of NMP, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0086] Example 9

[0087] At room temperature under a nitrogen atmosphere, 5.4 g (0.05 mol) of p-phenylenediamine (denoted as compound DA-1) and 4-(3,5-diaminophenyl)cyclohexanecarboxylic acid (denoted as compound DA-5) 11.715 g (0.05 mol) and 90.8 g of NMP (N-methyl-2-pyrrolidone) were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0088] Further add 259.4 g of NMP, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0089] Example 10

[0090] Under a room temperature environment and in a nitrogen atmosphere, 5.4 g (0.05 mol) of p-phenylenediamine (DA-1), 11.715 g (0.05 mol) of 4-(3,5-diaminophenyl)cyclohexanecarboxylic acid (DA-5) and 108.5 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then, 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0091] Further, 310.1 g of NMP was added, and stirring was carried out at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer, and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120°C for 1 hour, 150°C for 30 minutes, 200°C for 30 minutes, 250°C for 30 minutes, 300°C for 30 minutes, 350°C for 30 minutes, 400°C for 30 minutes, and 450°C for 30 minutes. After drying was completed, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm respectively.

[0092] Example 11

[0093] Under a room temperature environment and in a nitrogen atmosphere, 10.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 11.715 g (0.05 mol) of 4-(3,5-diaminophenyl)cyclohexanecarboxylic acid (DA-5) and 101.5 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then, 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0094] Further add 290.1 g of NMP, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is to dry at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0095] Example 12

[0096] In a room-temperature environment under a nitrogen atmosphere, add 20.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 11.715 g (0.05 mol) of 4-(3,5-diaminophenyl)cyclohexanecarboxylic acid (denoted as compound DA-5), and 119.3 g of NMP. Stir at room temperature for 30 minutes to confirm complete dissolution. Then add 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2), and stir at room temperature for 4 hours for a polymerization reaction to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0097] Further add 340.8 g of NMP, stir at room temperature for 30 minutes to confirm uniform dilution, and obtain a polyimide film precursor solution with a solid content of 10%. Spin-coat it evenly on a clean silicon wafer, and then dry it into a film in a circulating oven. The drying procedure is to dry at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, take it out of the oven and cool it naturally to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0098] Example 13

[0099] In a room-temperature environment under a nitrogen atmosphere, add 5.4 g (0.05 mol) of p-phenylenediamine (denoted as compound DA-1), diaminodiphenylimide ring-3,3'-dicarboxylic acid (denoted as compound DA-6) 18.465 g (0.05 mol) and 106.6 g of NMP (N-methyl-2-pyrrolidone) were stirred at room temperature for 30 minutes to confirm complete dissolution. Then, 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and the mixture was stirred at room temperature for 4 hours for a polymerization reaction to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0100] A further 304.4 g of NMP was added, and the mixture was stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying was completed, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm for the dry film thicknesses.

[0101] Example 14

[0102] In a room temperature environment under a nitrogen atmosphere, 5.4 g (0.05 mol) of p-phenylenediamine (DA-1), 18.465 g (0.05 mol) of diaminodiphenylimide cyclo-3,3'-dicarboxylic acid (DA-6), and 124.3 g of NMP were added. The mixture was stirred at room temperature for 30 minutes to confirm complete dissolution. Then, 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and the mixture was stirred at room temperature for 4 hours for a polymerization reaction to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0103] A further 355.1 g of NMP was added, and the mixture was stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying was completed, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm for the dry film thicknesses.

[0104] Example 15

[0105] In a room temperature environment and under a nitrogen atmosphere, 10.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 18.465 g (0.05 mol) of diaminodiphenylimide ring-3,3'-dicarboxylic acid (DA-6), and 117.3 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then, 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0106] Further, 335.1 g of NMP was added, and stirring was carried out at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120°C for 1 hour, 150°C for 30 minutes, 200°C for 30 minutes, 250°C for 30 minutes, 300°C for 30 minutes, 350°C for 30 minutes, 400°C for 30 minutes, and 450°C for 30 minutes. After drying was completed, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1μm, 5μm, 10μm, 15μm, and 20μm.

[0107] Example 16

[0108] In a room temperature environment and under a nitrogen atmosphere, 20.0 g (0.05 mol) of 4,4"-diaminodiphenyl ether (DA-2), 18.465 g (0.05 mol) of diaminodiphenylimide ring-3,3'-dicarboxylic acid (DA-6), and 135.0 g of NMP were added. Stir at room temperature for 30 minutes to confirm complete dissolution. Then, 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0109] Further, 385.8 g of NMP was added, and stirring was carried out at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120°C for 1 hour, 150°C for 30 minutes, 200°C for 30 minutes, 250°C for 30 minutes, 300°C for 30 minutes, 350°C for 30 minutes, 400°C for 30 minutes, and 450°C for 30 minutes. After drying was completed, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1μm, 5μm, 10μm, 15μm, and 20μm.

[0110] Comparative Example 1

[0111] At room temperature in a nitrogen atmosphere, 10.8 g (0.1 mol) of p-phenylenediamine (DA-1) and 76.1 g of NMP were added, and stirred at room temperature for 30 minutes to confirm complete dissolution. Then 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0112] A further 217.3 g of NMP was added, and stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer, and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0113] Comparative Example 2

[0114] At room temperature in a nitrogen atmosphere, 10.8 g (0.1 mol) of p-phenylenediamine (DA-1) and 93.8 g of NMP were added, and stirred at room temperature for 30 minutes to confirm complete dissolution. Then 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0115] A further 268.0 g of NMP was added, and stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer, and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0116] Comparative Example 3

[0117] At room temperature under a nitrogen atmosphere, 20.0 g (0.1 mol) of 4,4"-diaminodiphenyl ether (DA-2) and 97.5 g of NMP were added, and stirred at room temperature for 30 minutes to confirm complete dissolution. Then 21.8 g (0.1 mol) of pyromellitic dianhydride (DN-1) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0118] A further 278.7 g of NMP was added, and stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer, and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm respectively.

[0119] Comparative Example 4

[0120] At room temperature under a nitrogen atmosphere, 20.0 g (0.1 mol) of 4,4"-diaminodiphenyl ether (DA-2) and 115.3 g of NMP were added, and stirred at room temperature for 30 minutes to confirm complete dissolution. Then 29.4 g (0.1 mol) of 3,3",4,4"-biphenyltetracarboxylic dianhydride (DN-2) was added, and the polymerization reaction was carried out by stirring at room temperature for 4 hours to obtain a transparent viscous polyamic acid solution with a solid content of 30%.

[0121] A further 329.3 g of NMP was added, and stirred at room temperature for 30 minutes to confirm uniform dilution, obtaining a polyimide film precursor solution with a solid content of 10%. It was uniformly spin-coated on a clean silicon wafer, and then dried into a film in a circulating oven. The drying procedure was drying at 80 - 120 °C for 1 hour, 150 °C for 30 minutes, 200 °C for 30 minutes, 250 °C for 30 minutes, 300 °C for 30 minutes, 350 °C for 30 minutes, 400 °C for 30 minutes, and 450 °C for 30 minutes. After drying, it was taken out of the oven and naturally cooled to room temperature to obtain non-photosensitive polyimide films with five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm respectively.

[0122] The properties of the non-photosensitive polyimide films prepared in Examples 1 - 16 and Comparative Examples 1 - 4 were tested. The specific test methods and test results are as follows:

[0123] (1) Test the uniformity of film thickness

[0124] Testing equipment: Bruker Dektakxt-E profilometer

[0125] Calculation method for film thickness uniformity (U%): A total of ten groups of data are tested. U% = (Max - Min) / Avg. The smaller the value, the better the film thickness uniformity.

[0126] The film thickness uniformity data is shown in Table 1.

[0127] Table 1 Test results of film thickness uniformity when the polyamic acid solutions prepared in Examples 1 - 16 and Comparative Examples 1 - 4 are made into non-photosensitive polyimide films with different thicknesses

[0128]

[0129] It can be seen from the data in Table 1 that the U% data of the examples are lower than those of the comparative examples under different film thickness conditions, indicating that the present invention has a significant improvement in film thickness uniformity.

[0130] (2) Characterization of development effect

[0131] Testing method: Film is formed on a silicon wafer. The polyimide film precursor solutions with a solid content of 10% described in Examples 1 - 16 and Comparative Examples 1 - 4 are coated on glass and dried in a circulating oven at 130 °C for 1 hour. After taking it out of the oven, it is naturally cooled to room temperature to obtain a non-photosensitive polyimide film. A positive photoresist is coated on the non-photosensitive polyimide film and dried in a circulating oven at 100 °C for 90 s. After taking it out of the oven, it is naturally cooled to room temperature. The dry film thicknesses are controlled to be five different thicknesses of 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm respectively, and they are exposed respectively. The exposure process is 90 s, and it is soaked and shaken in 2.38% TMAH (tetramethylammonium hydroxide) for 60 s. The exposed positive photoresist and polyimide are washed off to obtain a photolithographic pattern, and then the surface photoresist is washed off with a stripping solution to obtain a polyimide film with a photolithographic pattern.

[0132] Test equipment: A double-sided alignment single-sided exposure device (mask aligner PEM-6M; manufactured by Union Optical (KK)) was used to perform patterned exposure using the i (365nm), h (405nm), and g (436nm) lines of an ultra-high pressure mercury lamp through a grayscale mask (MDRM M0DEL4000-5-FS; manufactured by OptoLine International), and then developed using a small photolithography developer (AD-2000; manufactured by Awasawa Sangyo Co., Ltd.). The resolution pattern of the produced cured film was observed using an FPD / LSI inspection microscope (OPTIPHOT-330; manufactured by UNION (W)), and the evaluation criteria for the development effect were as follows:

[0133] T1: The PI film lines and patterns left after development are clear, with no or minimal size changes and no residue.

[0134] T2: The PI film line pattern left after development has average clarity, large size changes, and some residue.

[0135] T3: The line pattern of the PI film left after development is blurred, the size changes greatly, and there is a lot of residue.

[0136] The evaluation results of the development effects of Examples 1 to 16 and Comparative Examples 1 to 4 are shown in Table 2.

[0137] Table 2 Development effect of non-photosensitive polyimide films of different film thicknesses prepared by using the polyimide film precursor solutions prepared in Examples 1 to 16 and Comparative Examples 1 to 4

[0138]

[0139]

[0140]

[0141] It can be seen from Table 2 that the developing performance of the embodiment is better than that of the comparative example under conditions of different film thicknesses, and developing defects are less likely to occur, indicating that the present invention has a significant improvement in developing performance.

[0142] (3) Heat resistance characterization

[0143] Test equipment:

[0144] 1. TMA (Q400) measures Tg (glass transition temperature) and CTE (coefficient of thermal expansion)

[0145] 2. TGA (NETZSCH TG 209F3) measurement of Td (thermal decomposition temperature)

[0146] Test method:

[0147] 1. Tg and CTE test method: Samples with a thickness of 5 microns, a length of 20 millimeters, and a width of 5 millimeters were tested. The temperature range for measurement was 50°C - 550°C, with a heating rate of 10°C / Min, and a constant tensile force of 0.05 N was continuously applied to the samples.

[0148] 2. Td test method: Weighed approximately 5 mg of the dried polyimide solid powder after precipitation, and the temperature range for measurement was 35°C - 900°C, with a heating rate of 10°C / Min.

[0149] The test results are shown in Table 3. It can be seen from the table that the heat resistance of the examples is better and remains at the same level as that of the comparative examples.

[0150] Table 3 Heat resistance test results of non-photosensitive polyimide materials with a thickness of 5μm prepared in Examples 1 - 16 and Comparative Examples 1 - 4

[0151]

[0152]

[0153] (4) Dielectric property characterization

[0154] Testing equipment: Dielectric constant tester Test method: A dielectric constant tester was used to test samples with a thickness of 5 microns, a length of 100 millimeters, and a width of 20 millimeters. The test results are shown in Table 4. It can be seen from the table that the dielectric performance of the examples is better and remains at the same level as that of the comparative examples.

[0155] Table 4 Dielectric property test results of non-photosensitive polyimide materials with a thickness of 5μm prepared in Examples 1 - 16 and Comparative Examples 1 - 4

[0156]

[0157]

[0158] (5) Mechanical property characterization

[0159] Test method: A universal material testing machine (WBE - 9010B) was used to test the mechanical properties of samples with a thickness of 5 microns, a length of 100 millimeters, and a width of 20 millimeters. The test results of the ultimate tensile strength, elongation at break, tensile modulus, etc. are shown in Table 5. It can be seen from the table that the mechanical properties of the examples are better and remain at the same level as that of the comparative examples.

[0160] Table 5 Mechanical property test results of non-photosensitive polyimide materials with a thickness of 5μm prepared in Examples 1 - 16 and Comparative Examples 1 - 4

[0161]

[0162]

[0163] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a non-photosensitive polyimide film, characterized in that: The following steps are involved: 1) mixing a diamine monomer without a carboxylic acid structure, a diamine monomer with a carboxylic acid structure, a polar aprotic solvent and a tetracarboxylic dianhydride monomer to perform a polymerization reaction to obtain a polyamic acid solution; 2) The polyamic acid solution obtained in step 1) is mixed with a polar aprotic solvent to obtain a polyimide film precursor solution, and the polyimide film precursor solution is sequentially coated and dried to obtain a non-photosensitive polyimide film.

2. The method for preparing a non-photosensitive polyimide film according to claim 1, characterized in that: The structural formula of the diamine monomer containing a carboxylic acid structure is shown in Formula I or Formula II: B1 in Formula I and Formula II is independently an alkyl chain, One or more of the following, wherein the general structural formula of the alkyl chain is C m H 2m , m is any integer between 0 and 20; B2 in formula II is selected from -COOH or -H, and the number of -COOH is 1 to 2.

3. The method for preparing a non-photosensitive polyimide film according to claim 2, characterized in that: The structural formula of the diamine monomer without a carboxylic acid structure is shown in Formula III or Formula IV: A in Formula III is one or more of an alkyl chain, -O-, -NH-, -S-, -SO2-, -COO-, -OCH2-, -CH2OCO, -CH2OCO-, -CH2O-, -NHCO-, -CONH-, -N(CH3)CO-, an olefin chain, an alkyne chain, a benzene ring, a cyclohexane, and an imide ring, wherein the general structural formula of the alkyl chain is C z H 2z , z is any integer between 0 and 20; In formula III and formula IV, R is independently selected from one or more of -H and -CH3.

4. The method for preparing a non-photosensitive polyimide film according to claim 3, characterized in that: The polar aprotic solvents in step 1) and step 2) independently include one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, m-cresol and tetrahydrofuran.

5. The method for preparing a non-photosensitive polyimide film according to claim 4, characterized in that: The structure of the tetracarboxylic dianhydride monomer is shown in Formula V: G1 in formula V is an aliphatic, cycloaliphatic or aromatic organic group.

6. The method for preparing a non-photosensitive polyimide film according to any one of claims 1 to 5, characterized in that: The addition ratio of the diamine monomer without carboxylic acid structure, the diamine monomer with carboxylic acid structure, the polar aprotic solvent and the tetracarboxylic dianhydride monomer is 0.03-0.08 mol: 0.03-0.08 mol: 100-120 g: 0.08-0.2 mol; The polymerization reaction is carried out at a temperature of -15 to 100°C and for a time of 1 to 24 hours.

7. The method for preparing a non-photosensitive polyimide film according to claim 6, characterized in that: The solid content of the polyamic acid in the polyimide film precursor solution is 1-40%.

8. The method for preparing a non-photosensitive polyimide film according to claim 7, characterized in that: The drying temperature is 50-500° C., and the drying time is 0.5-8 hours.

9. The method for preparing a non-photosensitive polyimide film according to claim 7 or 8, characterized in that: The thickness of the non-photosensitive polyimide film is 1-50 μm.

10. The non-photosensitive polyimide film prepared by the method for preparing a non-photosensitive polyimide film according to any one of claims 1 to 9.

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