A low-stress negative photosensitive polyimide resin glue solution, a preparation method and use thereof

Abstract

The application discloses a low-stress negative photosensitive polyimide resin glue solution, a preparation method and application thereof. The negative PSPI resin glue solution has excellent storage stability and photoetching processability, and can be used for forming a liquid glue film with uniform thickness on the surface of a large-area glass substrate through rotary coating, inkjet printing, curtain coating and other film forming processes. The liquid glue film can form a high-quality three-dimensional photoetching pattern after pre-baking, exposure, development, rinsing and heating and curing. The cured resin of the photoetching pattern has excellent comprehensive mechanical properties, moisture and heat resistance, chemical immersion corrosion resistance and high adhesion to copper. Meanwhile, the multilayer metal interconnection circuit (RDLs) structure formed by the negative PSPI resin glue solution has low internal stress, can obviously reduce the warping deformation degree of a reconstituted wafer, avoids interlayer cracking of the RDLs structure, and is suitable for manufacturing RDLs on the surface of a silicon wafer and a large-area glass substrate.

Description

Technical Field

[0001] This invention discloses a low-stress negative photosensitive polyimide resin liquid, its preparation method and uses, belonging to the field of polymer material preparation technology. Background Technology

[0002] In recent years, with the rapid development of advanced packaging technologies such as wafer-level packaging (WLP) and fan-out panel-level packaging (FLP), higher comprehensive performance requirements have been placed on dielectric materials used in multilayer metal interconnects (RDLs), including excellent photolithography processability, high resistance to humidity and heat, high strength and toughness, low curing temperature, and high adhesion to copper. However, as the number of metal wiring layers in RDLs increases, the overall thickness of the cured dielectric film also increases, leading to a significant increase in internal stress in the fabricated RDL structure. This often causes problems such as overall warpage, deformation, and interlayer cracking in the reconstructed wafer. Therefore, reducing the internal stress generated by PSPI resin during high-temperature curing, minimizing warpage deformation of the reconstructed wafer, and avoiding interlayer cracking in the RDL structure have become crucial challenges that advanced packaging technologies must address.

[0003] Existing technologies disclose various photosensitive resin compositions, whose cured films exhibit excellent adhesion to copper surfaces and resistance to chemical etching. However, these compositions require high curing temperatures and do not address techniques for reducing internal stress during curing. Furthermore, negative PSPI resins possess good photolithography processability and overall performance, but similarly fail to resolve the wafer warpage problem caused by high internal stress.

[0004] To address the aforementioned problems, this invention introduces flexible aliphatic ether segments with specific chain lengths into the main chain structure of photocrosslinked polyamide ester resin. By controlling the chain length and content of the flexible aliphatic chains, it achieves a significant reduction in curing internal stress while maintaining the high heat resistance and excellent overall performance of the resin film. This effectively solves the problems of warpage and interlayer cracking caused by high internal stress in wafer-level packaging and panel-level packaging. Summary of the Invention

[0005] In view of the above shortcomings, the present invention discloses a low-stress negative PSPI resin solution, its preparation method and application. The prepared low-stress negative PSPI resin solution has excellent storage stability and photolithography processability. At the same time, the multilayer metal interconnect circuit (RDLs) structure made by the negative PSPI resin solution has low internal stress, which can significantly reduce the warpage of the reconstructed wafer and avoid interlayer cracking of the RDLs structure.

[0006] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0007] This invention first discloses a low-stress negative photosensitive polyimide resin adhesive, comprising:

[0008] The composition includes 100 parts of photocrosslinkable polyamide ester resin, 50-150 parts of solvent, 0.01-20 parts of photocurable crosslinking agent, 0.01-10 parts of photocurable initiator, 0.01-10 parts of thermal crosslinking agent, 0.01-10 parts of low-temperature curing accelerator, 0.01-10 parts of polymerization inhibitor, 0.01-10 parts of copper discoloration inhibitor, 0.01-10 parts of tackifier, and 0.01-10 parts of toughening agent; wherein:

[0009] The main chain structure of the photocrosslinkable polyamic acid ester resin contains flexible aliphatic ether segments and hydroxyl (meth) acrylate groups that can undergo photocrosslinking reaction after ultraviolet light irradiation.

[0010] The flexible aliphatic ether segment is formed by the condensation polymerization of polyethylene glycol (n=1~6)-bis(4-phthalic anhydride) and aromatic diamine;

[0011] The residual internal stress of the resin after curing is less than or equal to 25 MPa.

[0012] Furthermore, the photocrosslinkable polyamic acid ester resin is prepared from aromatic tetracarboxylic dianhydride, hydroxyl-containing (meth)acrylate and aromatic diamine;

[0013] The aromatic tetracarboxylic dianhydride is selected from polyethylene glycol (n=1~6)-bis(4-phthalic anhydride), or a combination of polyethylene glycol (n=1~6)-bis(4-phthalic anhydride) and aromatic tetracarboxylic dianhydride-2; wherein the molar ratio of polyethylene glycol (n=1~4)-bis(4-phthalic anhydride) to aromatic tetracarboxylic dianhydride-2 is 1:(0~1).

[0014] Further, the aromatic tetracarboxylic dianhydride-2 is selected from at least one of pyromellitic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane and mixtures thereof in any proportion.

[0015] Further, the aromatic diamine is selected from at least one of 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)-benzene, 2,2-bis[4-(4-aminophenoxy)phenyl)]propane, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 1,3-bis(4-aminophenoxy)tetramethyldisiloxane, and mixtures thereof in any proportion.

[0016] Furthermore, the toughening agent is a thermoplastic polymer resin containing reactive functional groups with a weight average molecular weight of less than 100,000, selected from at least one of thermoplastic polyester resin, thermoplastic polyamide resin, thermoplastic polyetherimide resin, thermoplastic polyetheretherketone resin, thermoplastic polyphenylene sulfide resin, thermoplastic polyimide resin, silicone-modified polyimide resin, polymethacrylate resin and polyacrylate resin, and a mixture thereof in any proportion.

[0017] This invention also discloses a method for preparing a low-stress negative photosensitive polyimide resin liquid according to any of the above-mentioned methods, comprising:

[0018] (1) The photocrosslinkable polyamic acid ester resin is mixed with a solvent and stirred and dissolved under yellow light and nitrogen protection to form a homogeneous solution;

[0019] (2) Add photocurable crosslinking agent, photocurable initiator, thermal crosslinking agent, low-temperature curing accelerator, polymerization inhibitor, copper discoloration inhibitor, adhesion promoter and toughening agent to the homogeneous solution obtained in step (1), and stir until completely dissolved to form a homogeneous solution under yellow light region and nitrogen protection;

[0020] (3) Add an appropriate amount of solvent to adjust the solid content and viscosity of the solution, and finally filter to obtain negative PSPI resin solution.

[0021] Furthermore, the method for preparing the photocrosslinkable polyamic acid ester resin includes:

[0022] 1) Aromatic tetracarboxylic dianhydride and hydroxyl-containing (meth)acrylate are dissolved in an organic solvent and subjected to an esterification reaction under heating to form an aromatic diester dianhydride solution;

[0023] 2) The aromatic diester diacid solution is reacted with thionyl chloride to form the corresponding aromatic diester diacid chloride solution;

[0024] 3) Under cooling conditions, the solid aromatic diamine is added in portions to the above aromatic diester diacyl chloride solution, and the mixture is stirred at room temperature to 40°C for 0.1 to 10 hours; then a reactive end-capping agent is added, and the mixture is stirred to form a photocrosslinked polyamic acid ester resin solution.

[0025] Further, in step 1), the molar ratio of the aromatic tetracarboxylic dianhydride to the hydroxyl (meth)acrylate is 1:1.5~2.0, the esterification reaction temperature is 20~150℃, and the reaction time is 0.5~96h.

[0026] Further, in step 2), the molar ratio of the aromatic diester diacid to thionyl chloride is 1:1.5~3, the reaction temperature is -30~50℃, and the time is 1~48h.

[0027] Further, in step 3), the molar ratio of the aromatic diester diacyl chloride to the aromatic diamine is 1:0.8~1.2, the cooling temperature is -30~10℃, and the reaction time is 0.5~96h.

[0028] Furthermore, the resin solution has a high solids content, low solution viscosity, and good viscosity stability. When the solids content is 10~45 wt.%, the solution viscosity at room temperature is 100~5500 mPa·s, and the solution viscosity change rate is less than 10% after being placed at room temperature for 7 days.

[0029] The present invention also discloses the use of any of the above-described low-stress negative photosensitive polyimide resin solutions in the preparation of multilayer metal interconnect circuit structures in wafer-level packaging and panel-level packaging.

[0030] The present invention has the following advantages:

[0031] The negative PSPI resin solution described in this invention possesses excellent storage stability and photolithography processability. It can form a uniformly thick liquid film on the surface of a 12-inch silicon wafer using a spin-coating process, and also on a large-area (≥600mm×600mm) glass substrate using an inkjet printing process. The resin 3D pattern formed after photolithography processes such as pre-baking, exposure, and development exhibits high resolution and controllable steepness. The resin film formed after low-temperature curing (≤230℃) possesses excellent comprehensive mechanical properties, resistance to damp heat, resistance to chemical corrosion, and copper adhesion. Furthermore, the multilayer metal interconnect (RDLs) structure made from the negative PSPI resin solution has low internal stress, significantly reducing the warpage of the reconstructed wafer and preventing interlayer cracking in the RDL structure. It is suitable for fabricating RDLs on silicon wafer surfaces and large-area glass substrate surfaces. Attached Figure Description

[0032] Figure 1 This is a typical chemical structure of photocrosslinked polyamide ester resin. Detailed Implementation

[0033] Comprehensive performance evaluation method:

[0034] The preparation method of the negative photosensitive polyimide precursor resin solution is described in detail below through examples; the performance of the negative PSPI resin solution is evaluated using the following evaluation methods:

[0035] 1) Photolithography process: The negative photosensitive polyimide precursor resin liquid is applied to the surface of a large-area glass substrate by inkjet printing to form a liquid film of uniform thickness (12.0-12.5 μm); after baking at 100-125℃ for 1-3 min, a mask is placed on its surface and exposed with ultraviolet lamps (i and g lines); it is developed by spraying with cyclopentanone developer, rinsed with propylene glycol methyl ether acetate, and then cured by heating in a nitrogen-protected oven (150℃ / 1h, 200℃ / 1h, 230℃ / 1h) to obtain a cured resin stereolithographic pattern (8.0 μm). If the resolution of the raised strip pattern in the stereolithography is ≤8.0µm, the patterns are cleanly developed without any foreign matter residue, and the ratio of the bottom width to the top width of the raised strip pattern (steepness) is greater than 0.50, it is rated as "Excellent"; if the resolution of the raised strip pattern in the stereolithography is 8.1-9.9µm, the patterns are cleanly developed without any foreign matter residue, and the ratio of the bottom width to the top width of the raised strip pattern (steepness) is greater than 0.50, it is rated as "Good"; if the resolution of the raised strip pattern in the stereolithography is ≥10.0µm, the patterns are not cleanly developed with foreign matter residue, and the ratio of the top width to the bottom width of the raised strip pattern (steepness) is ≤0.50, it is rated as "Poor".

[0036] 2) Mechanical properties of the thin film: A negative photosensitive polyimide precursor resin was sprayed onto a large-area (600mm x 600mm) glass substrate surface by printing to form a uniformly thick film. After baking at 120℃ for 3 minutes, the film was exposed to ultraviolet light (i and g lines) without a mask. It was then developed by spraying with cyclopentanone developer, rinsed with propylene glycol methyl ether acetate, and cured in a nitrogen-protected oven (150℃ / 1h, 200℃ / 1h, 230℃ / 1h). Silicon wafers containing the resin film were immersed in 47% HF for 5-10 minutes, then rinsed with water to obtain a 10-12µm thick polyimide film. The polyimide film was cut into strips 1.0cm wide and 9.0cm long, and the mechanical properties of the film were tested using a tensile testing machine. The testing rate was 50 mm / min, with 7 samples per group. The 5 highest values ​​were averaged to obtain tensile strength and elongation at break. If the tensile strength of the prepared polyimide film is ≥100 MPa and the elongation at break is ≥40%, it is rated as "Excellent"; if the tensile strength of the prepared polyimide film is ≥100 MPa and the elongation at break is 21-39%, it is rated as "Good"; if the tensile strength of the prepared polyimide film is ≤100 MPa and the elongation at break is ≤20%, it is rated as "Poor".

[0037] 3) Adhesion to Copper Surface: A negative photosensitive polyimide precursor resin was inkjet printed onto a large-area (600mm x 600mm) glass substrate to form a uniformly thick film. After baking at 100-110℃ for 1-3 minutes, the film was exposed to UV light (i and g lines) without a mask. It was then developed using cyclopentanone developer, rinsed with propylene glycol methyl ether acetate, and cured in a nitrogen-protected oven (150℃ / 1h, 200℃ / 1h, 230℃ / 1h) to obtain an 8.0 µm thick polyimide film. The adhesion between the film and copper was evaluated using a cross-cut test: 0 crosses peeled off per 100 crosses was considered "Excellent"; 1-10 crosses peeled off per 100 crosses was considered "Good"; and more than 11 crosses peeled off per 100 crosses was considered "Poor".

[0038] 4) Chemical resistance: The heat-cured polyimide photolithographic pattern was immersed in a caustic solution (1 wt.% potassium hydroxide + 39 wt.% 3-methoxy-3-methyl-1-butanol + 60 wt.% dimethyl sulfoxide (DMSO)) at 100°C for 1 hour. After washing with water and air drying, the chemical resistance of the polyimide film was evaluated by measuring the change in film thickness and observing under an optical microscope: if the change in the thickness of the polyimide film after immersion is within ±1% and no cracks or defects are produced, it is rated as "excellent"; if the change in the thickness of the polyimide film after immersion is within ±1.1-2.9% and no cracks or defects are produced, it is rated as "good"; if the change in the thickness of the polyimide film after immersion exceeds ±3.0% or cracks or defects are produced, it is rated as "poor".

[0039] 5) Moisture and heat resistance: A negative photosensitive polyimide precursor resin was sprayed onto a large-area glass substrate with copper-tin bumps of 15µm height to form a liquid film. After baking at 120℃ for 3 minutes, the substrate was exposed to UV lamps (i and g lines) without a mask. The substrate was then developed by spraying with cyclopentanone developer, rinsed with propylene glycol methyl ether acetate, and cured in a nitrogen-protected oven (150℃ / 1h, 200℃ / 1h, 230℃ / 1h) to form a cured polyimide layer on the substrate surface. The substrate was then placed in a pressure cooker at 120℃ / 2 atm for 100 hours and subjected to three thermal shock cycles from room temperature to 260℃. The longitudinal section of the copper-tin bumps covered with the polyimide film was cut using FIB, and the interface morphology between the copper-tin bumps and the polyimide resin was observed using an optical microscope. If no cracks or voids are found at the interface between the copper-tin protrusion and the polyimide resin, it is rated as "excellent"; if a few cracks or voids are found at the interface between the copper-tin protrusion and the polyimide resin, it is rated as "good"; if many cracks or voids are found at the interface between the copper-tin protrusion and the polyimide resin, it is rated as "poor".

[0040] 6) Residual Internal Stress: A negative PSPI resin solution was spin-coated onto a 12-inch silicon wafer to form a uniform liquid film. After baking at 120°C for 3 minutes, the film was exposed to UV light (i and g lines) without a mask. It was then developed using cyclopentanone developer, rinsed with propylene glycol methyl ether acetate, and cured in a nitrogen-protected oven (150°C / 1h, 200°C / 1h, 230°C / 1h) to form a 10µm thick polyimide film. The internal stress of the cured film was tested at room temperature using a film internal stress testing device (model FLX-2320, manufactured by KL-Tencor). A residual internal stress ≤25 MPa was rated "Excellent"; a residual internal stress in the range of 25-29 MPa was rated "Good"; and a residual internal stress ≥30 MPa was rated "Poor".

[0041] 7) Overall performance: If all indicators are "Excellent", the overall performance is rated as "Excellent"; if one indicator is "Good", the overall performance is rated as "Good"; if one indicator is "Poor", the overall performance is rated as "Poor".

[0042] Polyamate ester (PAE) resin synthesis:

[0043] Resin Synthesis Example 1

[0044] In a 500 ml three-necked round-bottom flask equipped with a mechanical stirrer, thermometer, and nitrogen protection device, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA, Mw=330.17), 26.03 g (0.20 mol.) 2-hydroxyethyl methacrylate (HEMA), 15.82 g (0.20 mol.) pyridine, and 129 g N-methylpyrrolidone (NMP) were added. The mixture was stirred at room temperature for 6 h to produce the corresponding aromatic diacid dimethacrylate. The above product was then reacted with 23.79 g SOCl2 at 0-10 °C for 2 h, followed by a reaction at room temperature for 4 h to produce a solution of the corresponding 1-PEPA diacyl chloride dimethacrylate.

[0045] In a 1L three-necked round-bottom flask equipped with a mechanical stirrer, thermometer, and nitrogen protection device, 20.02g (0.10 mol.) of 4,4'-diaminodiphenyl ether (44ODA) and 158g of NMP were added and stirred until dissolved to form a homogeneous transparent solution (44-ODA / NMP). The 1-PEPA diacyl chloride dimethacrylate solution prepared above was added dropwise to the 44-ODA / NMP solution over a period of 0.5h. The reaction was then allowed to proceed at room temperature for 10h. 1.48g (0.01 mol.) of phthalic anhydride was then added and stirring was continued for 1h. The reaction solution was poured into 5L of deionized water, the solid precipitated, filtered, and dried under vacuum to obtain primary polyaminate resin (PAE-1-1). It is then dissolved in tetrahydrofuran to form a solution, and residual metal or non-metal ions are removed by adsorption with anionic and cationic resins to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-1:1-PEPA-44-ODA).

[0046] Resin Synthesis Example 2

[0047] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 33.02 g (0.10 mol.) polyethylene glycol (n=2)-bis(4-phthalic anhydride) (abbreviated as: 2-PEPA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-2: 2-PEPA-44-ODA).

[0048] Resin Synthesis Example 3

[0049] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 33.02 g (0.10 mol.) polyethylene glycol (n=3)-bis(4-phthalic anhydride) (abbreviated as: 3-PEPA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-3: 3-PEPA-44-ODA).

[0050] Resin Synthesis Example 4

[0051] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced with 33.02 g (0.10 mol.) polyethylene glycol (n=4)-bis(4-phthalic anhydride) (abbreviated as: 4-PEPA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-4: 4-PEPA-44-ODA).

[0052] Resin Synthesis Example 5

[0053] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 33.02 g (0.10 mol.) polyethylene glycol (n=5)-bis(4-phthalic anhydride) (abbreviated as: 5-PEPA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-5: 5-PEPA-44-ODA).

[0054] Resin Synthesis Example 6

[0055] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 33.02 g (0.10 mol.) polyethylene glycol (n=6)-bis(4-phthalic anhydride) (abbreviated as: 6-PEPA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-6: 6-PEPA-44-ODA).

[0056] Resin Synthesis Example 7

[0057] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 16.51 g (0.05 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) and 10.09 g (0.05 mol.) pyromellitic anhydride (abbreviated as: PMDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-7: 1PEPA / PMDA(1 / 1)-44ODA).

[0058] Resin Synthesis Example 8

[0059] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 16.51 g (0.05 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) and 16.11 g (0.05 mol.) benzophenone tetracarboxylic dianhydride (abbreviated as: 44-BTDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-8: 1-PEPA / 44-BTDA(1 / 1)-44-ODA).

[0060] Resin Synthesis Example 9

[0061] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 16.51 g (0.05 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) and 14.71 g (0.05 mol.) 3,3,4',4'-biphenyltetracarboxylic dianhydride (abbreviated as: 44-BPDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-9: 1-PEPA / 44-BPDA(1 / 1)-44-ODA).

[0062] Resin Synthesis Example 10

[0063] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 16.51 g (0.05 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) and 22.21 g (0.05 mol.) 2,2-bis(4-phenyltetracarboxylic anhydride) hexafluoropropane (abbreviated as: 6FDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-10: 1-PEPA / 6FDA(1 / 1)-44-ODA).

[0064] Resin Synthesis Example 11

[0065] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 16.51 g (0.05 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) and 15.53 g (0.05 mol.) 3,3,4',4'-diphenyl ether tetracarboxylic dianhydride (abbreviated as: 44-ODPA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-11: 1PEPA / 44-ODPA(1 / 1)-44ODA).

[0066] Resin Synthesis Example 12

[0067] In resin synthesis example 11, 20.02 g (0.10 mol.) 4,4'-diaminodiphenyl ether (44ODA) was replaced by 20.02 g (0.10 mol.) 3,4'-diaminodiphenyl ether (34-ODA) to obtain a high-purity polyimide precursor resin solid (abbreviation: PAE-1-12: 1-PEPA / 44-ODPA(1 / 1)-34-ODA).

[0068] Resin Synthesis Example 13

[0069] In resin synthesis example 10, 20.02 g (0.10 mol.) of 4,4'-diaminodiphenyl ether (44ODA) was replaced by 29.22 g (0.10 mol.) of 1,4-bis(3-aminophenoxy)-benzene (abbreviated as 134-APB) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-13: 1-PEPA / 44-ODPA(1 / 1)-134-APB).

[0070] Resin Synthesis Example 14

[0071] In resin synthesis example 10, 20.02 g (0.10 mol.) of 4,4'-diaminodiphenyl ether (44-ODA) was replaced by 29.22 g (0.10 mol.) of 1,4-bis(4-aminophenoxy)-benzene (abbreviated as 144APB) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-14: 1-PEPA / 44-ODPA(1 / 1)-144-APB).

[0072] Resin Synthesis Example 15

[0073] In resin synthesis example 10, 20.02 g (0.10 mol.) 4,4'-diaminodiphenyl ether (44-ODA) was replaced by 41.03 g (0.10 mol.) 2,2-bis[4-(4-aminophenoxy)phenyl)]propane (abbreviated as BAPP) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-15: 1-PEPA / 44-ODPA(1 / 1)-BAPP).

[0074] Resin Synthesis Example 16

[0075] In resin synthesis example 10, 20.02 g (0.10 mol.) of 4,4'-diaminodiphenyl ether (44ODA) was replaced by 42.82 g (0.10 mol.) of 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (abbreviated as: 6FAPB) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-16: 1-PEPA / 44-ODPA(1 / 1)-6FAPB).

[0076] Resin Synthesis Example 17

[0077] In resin synthesis example 10, 20.02 g (0.10 mol.) of 4,4'-diaminodiphenyl ether (44-ODA) was replaced by 50.43 g (0.10 mol.) of 1,4-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (abbreviated as: 6FBAB) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-1-17: 1-PEPA / 44-ODPA(1 / 1)-6FBAB).

[0078] Comparative Synthesis Example 1

[0079] In resin synthesis example 1, 33.02 g (0.10 mol.) polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 32.22 g (0.10 mol.) benzophenone tetracarboxylic dianhydride (abbreviated as: 44-BTDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-2-1: 44-BTDA-44ODA).

[0080] Comparative Synthesis Example 2

[0081] In resin synthesis example 1, 33.02 g (0.10 mol.) of polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 29.42 g (0.10 mol.) of 3,3,4',4'-biphenyltetracarboxylic dianhydride (abbreviated as: BPDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-2-2: 44-BPDA-44-ODA).

[0082] Comparative Synthesis Example 3

[0083] In resin synthesis example 11, 33.02 g (0.10 mol.) of polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 21.81 g (0.10 mol.) of pyromellitic dianhydride (abbreviated as: PMDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-2-3: PMDA / 44-ODPA(1 / 1)-44-ODA).

[0084] Comparative Synthesis Example 4

[0085] In resin synthesis example 11, 33.02 g (0.10 mol.) of polyethylene glycol (n=1)-bis(4-phthalic anhydride) (abbreviated as: 1-PEPA) was replaced by 29.42 g (0.10 mol.) of biphenyltetracarboxylic dianhydride (abbreviated as: 44-BPDA) to obtain a high-purity polyimide precursor resin solid (abbreviated as: PAE-2-4: 44-BPDA / 44-ODPA(1 / 1)-44-ODA).

[0086] Negative photosensitive PSPI resin liquid

[0087] Examples 1-5 and Comparative Examples 1-2

[0088] Example 1

[0089] In a cleanroom equipped with a yellow light, 100g of the polyimide precursor resin PAE-1-1 prepared in Example 1 of the present invention was weighed and dissolved in a mixed solvent (B) of 80g NMP and 20g ethyl lactate (EL) to form a homogeneous solution. Then, the following components were added sequentially: photocurable monomer (C): 8g ethylene glycol diethyl ether methacrylate (4EM), photocurable initiator (D-1): 1.0g 1-phenyl-1,2-propanedione-2-(O-ethoxycarbonyl) oxime, and other components (E). The other components (E) included 0.25g diarylsulfonium salt (E-1), 2.5g 2,6-dimethoxymethyl-4-tert-butylphenol (E-2), 0.5g bis(triethanolamine)diisopropoxide titanium (E-3), 0.5g 5-methyl-1H-benzotriazole (E-4), and 0.5g... N-Phenylacetyldiethanolamine (E-5), 0.5 g of γ-glycidyl etheroxypropyltrimethoxysilane (E-6), and 0.5 g of N-nitrosodiphenylamine (E-7) were stirred at room temperature for 1 h to obtain a negative PSPI resin composition solution. The prepared negative PSPI resin solution had a solids content of 35 wt.% and a solution viscosity of 3500 mPa·s.

[0090] The aforementioned negative PSPI resin solution is uniformly coated onto the surface of a 12-inch silicon wafer or a large-area glass substrate using a spin coating process. After baking at 100-110℃ for 1-3 minutes, a mask is placed on the surface and exposed using ultraviolet lamps (i and g lines). The substrate is then developed by spraying with cyclopentanone developer, rinsed with propylene glycol methyl ether acetate, and cured in a nitrogen-protected oven (150℃ / 1h, 200℃ / 1h, 230℃ / 1h) to obtain a stereolithographic pattern formed by curing the polyimide film.

[0091] The performance of the prepared negative PSPI resin solution was evaluated using the above evaluation method. The evaluation results are as follows: ① Photolithography processability: pattern steepness is 0.85, photolithography resolution is 7.5μm, rated as "excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength is 110MPa, elongation at break is 52%, rated as "excellent"; ③ Copper adhesion: cross-cut adhesion test result is 0 / 100, rated as "excellent"; ④ Chemical corrosion resistance: film thickness change rate is 0.66%, no microcracks or defects were observed, rated as "excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "excellent"; ⑥ Residual internal stress: 20 MPa, rated as "excellent"; ⑦ Comprehensive performance evaluation: all indicators are excellent, rated as "excellent".

[0092] Example 2

[0093] In Example 1, PAE-1-1 was replaced with PAE-1-2, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.87, photolithography resolution was 7.6 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 115 MPa, elongation at break was 45%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.64%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 18 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0094] Example 3

[0095] In Example 1, PAE-1-1 was replaced with PAE-1-3, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.89, photolithography resolution was 6.4 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 107 MPa, elongation at break was 62%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.68%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 19 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0096] Example 4

[0097] In Example 1, PAE-1-1 was replaced with PAE-1-4, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.90, photolithography resolution was 6.8 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 112 MPa, elongation at break was 56%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.57%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 18 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0098] Example 5

[0099] In Example 1, PAE-1-1 was replaced with PAE-1-5, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.91, photolithography resolution was 6.6 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 110 MPa, elongation at break was 58%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.59%, a small number of microcracks or defects were observed, rated as "Good"; ⑤ Damp heat resistance: a small number of microcracks or defects were observed, rated as "Good"; ⑥ Residual internal stress: 18 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: two indicators were good, rated as "Good".

[0100] Example 6

[0101] In Example 1, PAE-1-1 was replaced with PAE-1-6, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.87, photolithography resolution was 6.8 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 105 MPa, elongation at break was 65%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.56%, a small number of microcracks or defects were observed, rated as "Good"; ⑤ Damp heat resistance: a small number of microcracks or defects were observed, rated as "Good"; ⑥ Residual internal stress: 20 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: two indicators were good, rated as "Good".

[0102] Comparative Example 1

[0103] PAE-1-1 in Example 1 was replaced by PAE-2-1 in Comparative Synthesis Example 1, with all other aspects remaining the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.88, photolithography resolution was 9.8 μm, rated as "Good"; ② Comprehensive mechanical properties of the thin film: tensile strength was 135 MPa, elongation at break was 45%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 8 / 100, rated as "Good"; ④ Chemical corrosion resistance: film thickness change rate was 0.68%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 35 MPa, rated as "Poor"; ⑦ Comprehensive performance evaluation: one indicator was poor, rated as "Poor".

[0104] Comparative Example 2

[0105] PAE-1-1 in Example 1 was replaced by PAE-2-2 in Comparative Synthesis Example 2, with all other aspects remaining the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.85, photolithography resolution was 10.8 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 118 MPa, elongation at break was 55%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 8 / 100, rated as "Good"; ④ Chemical corrosion resistance: film thickness change rate was 0.73%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 36 MPa, rated as "Poor"; ⑦ Comprehensive performance evaluation: two indicators were poor, rated as "Poor".

[0106] Table 1 compares the effects of changes in the main chain structure of the photosensitive polyaminate resins PAE-1 series (including PAE-1-1, 1-2, 1-3, 1-4, 1-5, and 1-6) on the overall properties of the prepared negative photosensitive PSPI resins from Examples 1 to 6. The results show that the photosensitive PSPI resin solution formed by thoroughly mixing PAE-1-1 or PAE-1-2, PAE-1-3, and PAE-1-4 as photocrosslinking polyaminate resins with photocrosslinking agents, photocuring initiators, thermal crosslinking agents, low-temperature curing accelerators, polymerization inhibitors, copper discoloration inhibitors, tackifiers, and toughening agents exhibits excellent overall properties. However, when the photosensitive polyaminate resin is PAE-1-5 or PAE-1-6, the overall properties of the prepared negative photosensitive PSPI resin are poor. In addition, the photolithographic processability and residual internal stress of the negative photosensitive PSPI resin prepared by replacing 1PEPA with 44-BTDA or 44-BPDA were rated as "poor".

[0107] Table 1 Comparison of results between Examples 1-6 and Comparative Examples 1-2

[0108] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 PAE-1 PAE-1-11-PEPA-44-ODA PAE-1-22-PEPA-44-ODA PAE-1-33-PEPA-44-ODA PAE-1-44-PEPA-44-ODA PAE-1-55-PEPA-44-ODA PAE-1-66-PEPA-44-ODA PAE-2-144-BTDA-44-ODA PAE-2-244-BPDA-44-ODA Solid content of adhesive (wt.%) 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 Adhesive viscosity, mPa·s (23℃) 3500±100 3500±100 3500±100 3500±100 3500±100 3500±100 3500±100 3500±100 Curing temperature (°C / h) 230 / 1 230 / 1 230 / 1 230 / 1 230 / 1 230 / 1 230 / h 230 / h

[0109] Example 7

[0110] In Example 1, PAE-1-1 was replaced with PAE-1-7, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.90, photolithography resolution was 9.5 μm, rated as "Good"; ② Comprehensive mechanical properties of the thin film: tensile strength was 130 MPa, elongation at break was 51%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.68%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 32 MPa, rated as "Poor"; ⑦ Comprehensive performance evaluation: one indicator was poor, rated as "Poor".

[0111] Example 8

[0112] In Example 1, PAE-1-1 was replaced with PAE-1-8, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.91, photolithography resolution was 7.2 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 125 MPa, elongation at break was 44%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.66%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 20 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0113] Example 9

[0114] In Example 1, PAE-1-1 was replaced with PAE-1-9, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.88, photolithography resolution was 9.4 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 127 MPa, elongation at break was 63%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.64%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 28 MPa, rated as "Good"; ⑦ Comprehensive performance evaluation: two indicators were good, rated as "Good".

[0115] Example 10

[0116] In Example 1, PAE-1-1 was replaced with PAE-1-10, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.86, photolithography resolution was 6.8 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 112 MPa, elongation at break was 56%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.56%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 24 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0117] Example 11

[0118] In Example 1, PAE-1-1 was replaced with PAE-1-11, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.89, photolithography resolution was 6.8 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 120 MPa, elongation at break was 57%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.59%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 18 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0119] Comparative Example 3

[0120] PAE-1-1 in Example 1 was replaced by PAE-2-3 in Comparative Synthesis Example 3, with all other aspects remaining the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.86, photolithography resolution was 9.4 μm, rated as "Good"; ② Comprehensive mechanical properties of the thin film: tensile strength was 134 MPa, elongation at break was 46%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 8 / 100, rated as "Good"; ④ Chemical corrosion resistance: film thickness change rate was 0.68%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 33 MPa, rated as "Poor"; ⑦ Comprehensive performance evaluation: one indicator was poor, rated as "Poor".

[0121] Comparative Example 4

[0122] PAE-1-1 in Example 1 was replaced by PAE-2-4 in Comparative Synthesis Example 4, with all other aspects remaining the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.84, photolithography resolution was 10.8 μm, rated as "poor"; ② Comprehensive mechanical properties of the thin film: tensile strength was 128 MPa, elongation at break was 55%, rated as "excellent"; ③ Copper adhesion: cross-cut adhesion test result was 8 / 100, rated as "good"; ④ Chemical corrosion resistance: film thickness change rate was 0.73%, no microcracks or defects were observed, rated as "excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "excellent"; ⑥ Residual internal stress: 34 MPa, rated as "poor"; ⑦ Comprehensive performance evaluation: two indicators were poor, rated as "poor".

[0123] Table 2 compares the effects of changes in the resin backbone structure caused by different monomer molecular structures in the aromatic dianhydride mixtures of the PAE-1 series of photosensitive polyaminate resins (PAE-1-7, 1-8, 1-9, 1-10, 1-11) from Examples 7 to 11 on the overall performance of the prepared negative photosensitive PSPI resins. The results show that the photosensitive PSPI resin solution prepared by thoroughly mixing PAE resin (PAE-1-8 or PAE-1-10, PAE-1-11) as the photocrosslinking polyaminate resin with photocrosslinking agents, photocuring initiators, thermal crosslinking agents, low-temperature curing accelerators, polymerization inhibitors, copper discoloration inhibitors, tackifiers, and toughening agents exhibits excellent overall performance; while the overall performance of the photosensitive PSPI resin solution prepared by using PAE-1-7 or PAE-1-9 as the photocrosslinking polyaminate resin is rated as "good or poor". The overall performance evaluation of negative photosensitive PSPI resins prepared by replacing 1-PEPA with PMDA or BPDA is "poor".

[0124] Table 2 Comparison of results between Examples 7-11 and Comparative Examples 3-4

[0125] Example 7 Example 8 Example 9 Example 10 Example 11 Comparative Example 3 Comparative Example 4 PAE-1 PAE-1-71-PEPA / PMDA(1 / 1)-44-ODA PAE-1-81-PEPA / 44-BTDA(1 / 1)-44-ODA PAE-1-91-PEPA / 44-BPDA(1 / 1)-44-ODA PAE-1-101-PEPA / 6FDA(1 / 1)-44-ODA PAE-1-111-PEPA / 44-ODPA(1 / 1)-44-ODA PAE-2-3PMDA / 44-ODPA(1)-44-ODA PAE-2-444-BPDA / 44-ODPA(1 / 1)-44-ODA Solid content of adhesive (wt.%) 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 Adhesive viscosity, mPa·s (23℃) 3500±100 3500±100 3500±100 3500±100 3500±100 3500±100 3500±100 Curing temperature (°C / h) 230 / 1 230 / 1 230 / 1 230 / 1 230 / 1 230 / h 230 / h

[0126] Example 12

[0127] In Example 1, PAE-1-1 was replaced with PAE-1-12, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.92, photolithography resolution was 6.5 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 125 MPa, elongation at break was 48%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.66%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 19 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0128] Example 13

[0129] In Example 1, PAE-1-1 was replaced with PAE-1-13, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.91, photolithography resolution was 6.8 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 123 MPa, elongation at break was 46%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.64%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 18 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0130] Example 14

[0131] In Example 1, PAE-1-1 was replaced with PAE-1-14, while other aspects remained the same, to obtain a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated for performance using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.90, photolithography resolution was 6.4 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 122 MPa, elongation at break was 65%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.66%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 20 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0132] Example 15

[0133] In Example 1, PAE-1-1 was replaced with PAE-1-15, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.89, photolithography resolution was 6.5 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 122 MPa, elongation at break was 66%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.57%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 21 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0134] Example 16

[0135] In Example 1, PAE-1-1 was replaced with PAE-1-16, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.88, photolithography resolution was 6.7 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 125 MPa, elongation at break was 56%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.56%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 18 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0136] Example 17

[0137] In Example 1, PAE-1-1 was replaced with PAE-1-17, while other aspects remained the same, resulting in a negative PSPI resin solution. The prepared negative PSPI resin solution was evaluated using the aforementioned evaluation method. The evaluation results were as follows: ① Photolithography processability: pattern steepness was 0.91, photolithography resolution was 6.4 μm, rated as "Excellent"; ② Comprehensive mechanical properties of the thin film: tensile strength was 127 MPa, elongation at break was 55%, rated as "Excellent"; ③ Copper adhesion: cross-cut adhesion test result was 0 / 100, rated as "Excellent"; ④ Chemical corrosion resistance: film thickness change rate was 0.56%, no microcracks or defects were observed, rated as "Excellent"; ⑤ Damp heat resistance: no microcracks or defects were observed, rated as "Excellent"; ⑥ Residual internal stress: 19 MPa, rated as "Excellent"; ⑦ Comprehensive performance evaluation: all indicators were excellent, rated as "Excellent".

[0138] Table 3 compares the effects of changes in the resin backbone structure caused by the different monomer molecular structures of the aromatic dianhydride mixture in the PAE-1 series of photosensitive polyaminate resins (PAE-1-12, 1-13, 1-14, 1-15, 1-16, 1-17) from Examples 12 to 17 on the overall performance of the prepared negative photosensitive PSPI resins. The results show that the photosensitive PSPI resin solutions formed by thoroughly mixing PAE-1 resins (PAE-1-12, 1-13, 1-14, 1-15, 1-16, 1-17) as photocrosslinking polyaminate resins with photocrosslinking agents, photocuring initiators, thermal crosslinking agents, low-temperature curing accelerators, polymerization inhibitors, copper discoloration inhibitors, tackifiers, and toughening agents all received an "excellent" overall performance evaluation.

[0139] Table 3 Comparison of results from Examples 12-17

[0140] Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 PAE-1 PAE-1-121PEPA / ODPA(1 / 1)-34ODA PAE-1-131PEPA / ODPA(1 / 1)-134APB PAE-1-141PEPA / ODPA(1 / 1)-144APB PAE-1-151PEPA / ODPA(1 / 1)-BAPP PAE-1-161PEPA / ODPA(1 / 1)-6FAPB PAE-1-171PEPA / ODPA(1 / 1)-6FBAB Solid content of adhesive (wt.%) 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 35±2.0 Adhesive viscosity, mPa·s (23℃) 3500±100 3500±100 3500±100 3500±100 3500±100 3500±100 Curing temperature (°C / h) 230 / 1 230 / 1 230 / 1 230 / 1 230 / 1 230 / 1

[0141] The results above demonstrate that the photosensitive PSPI resin solution, formed by thoroughly mixing photosensitive polyaminate resin, photocrosslinking agent, photocuring initiator, thermal crosslinking agent, low-temperature curing accelerator, polymerization inhibitor, copper discoloration inhibitor, adhesion promoter, and toughening agent, exhibits excellent storage stability and photolithography processability, forming a uniformly thick liquid film on the surface of silicon wafers or glass substrates. This liquid film, after pre-baking, exposure, development, rinsing, and low-temperature curing, can form high-quality three-dimensional photolithographic patterns. The cured resin of the formed photolithographic patterns possesses excellent comprehensive mechanical properties, resistance to damp heat, resistance to chemical corrosion, and high adhesion to copper. Furthermore, the multilayer metal interconnect (RDL) structure fabricated using the negative PSPI resin solution exhibits low residual internal stress, which helps reduce warpage deformation of the reconstructed wafer and avoids interlayer cracking in the RDL structure, making it suitable for fabricating RDLs on silicon wafer surfaces and large-area glass substrate surfaces.

Claims

1. A low-stress negative photosensitive polyimide resin adhesive, comprising: The composition includes 100 parts of photocrosslinkable polyamide ester resin, 50-150 parts of solvent, 0.01-20 parts of photocurable crosslinking agent, 0.01-10 parts of photocurable initiator, 0.01-10 parts of thermal crosslinking agent, 0.01-10 parts of low-temperature curing accelerator, 0.01-10 parts of polymerization inhibitor, 0.01-10 parts of copper discoloration inhibitor, 0.01-10 parts of tackifier, and 0.01-10 parts of toughening agent; wherein: The main chain structure of the photocrosslinkable polyamic acid ester resin contains flexible aliphatic ether segments and (meth)acrylate groups that can undergo photocrosslinking reaction after being irradiated by ultraviolet light. The flexible aliphatic ether segment is formed by polycondensation reaction of polyethylene glycol (n=1~4)-bis(4-phthalic anhydride) and aromatic diamine; The residual internal stress of the resin after curing is ≤25 MPa.

2. The resin adhesive according to claim 1, wherein: The photocrosslinkable polyamic acid ester resin is prepared from aromatic tetracarboxylic acid dianhydride, hydroxyl (meth)acrylate, and aromatic diamine; The aromatic tetracarboxylic dianhydride is selected from polyethylene glycol (n=1~6)-bis(4-phthalic anhydride), or a combination of polyethylene glycol (n=1~6)-bis(4-phthalic anhydride) and aromatic tetracarboxylic dianhydride-2; wherein the molar ratio of polyethylene glycol (n=1~6)-bis(4-phthalic anhydride) to aromatic tetracarboxylic dianhydride-2 is 1:(0~1).

3. The resin adhesive according to claim 2, wherein: The aromatic tetracarboxylic dianhydride-2 is selected from at least one of the following: pyromellitic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl sulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane, and mixtures thereof in any proportion.

4. The resin adhesive according to claim 2, wherein: The aromatic diamine is selected from at least one of the following: 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)-benzene, 2,2-bis[4-(4-aminophenoxy)phenyl)]propane, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)biphenyl, 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 1,3-bis(4-aminophenoxy)tetramethyldisiloxane, and mixtures thereof in any proportion.

5. The resin adhesive according to claim 1, wherein: The toughening agent is a thermoplastic polymer resin containing reactive functional groups with a weight average molecular weight of less than 100,000, selected from at least one of thermoplastic polyester resin, thermoplastic polyamide resin, thermoplastic polyetherimide resin, thermoplastic polyetheretherketone resin, thermoplastic polyphenylene sulfide resin, thermoplastic polyimide resin, silicone-modified polyimide resin, polymethacrylate resin and polyacrylate resin, and a mixture thereof in any proportion.

6. A method for preparing a low-stress negative photosensitive polyimide resin liquid according to any one of claims 1 to 5, comprising: (1) The photocrosslinkable polyamic acid ester resin is mixed with a solvent and stirred and dissolved under yellow light and nitrogen protection to form a homogeneous solution; (2) Add photocurable crosslinking agent, photocurable initiator, thermal crosslinking agent, low-temperature curing accelerator, polymerization inhibitor, copper discoloration inhibitor, adhesion promoter and toughening agent to the homogeneous solution obtained in step (1), and stir until completely dissolved to form a homogeneous solution under yellow light region and nitrogen protection; (3) Add an appropriate amount of solvent to adjust the solid content and viscosity of the solution, and finally filter to obtain negative PSPI resin solution.

7. The preparation method according to claim 6, wherein: The preparation method of the photocrosslinkable polyamic acid ester resin includes: 1) Aromatic tetracarboxylic dianhydride and hydroxyl-containing (meth)acrylate are dissolved in an organic solvent and subjected to an esterification reaction under heating to form an aromatic diester dianhydride solution; 2) The aromatic diester diacid solution is reacted with thionyl chloride to form the corresponding aromatic diester diacid chloride solution; 3) Under cooling conditions, the solid aromatic diamine is added in portions to the above aromatic diester diacyl chloride solution, and the mixture is stirred at room temperature to 40°C for 0.1 to 10 hours; then a reactive end-capping agent is added, and the mixture is stirred to form a photocrosslinked polyamic acid ester resin solution.

8. The preparation method according to claim 7, wherein: In step 1), the molar ratio of the aromatic tetracarboxylic dianhydride to the hydroxyl (meth)acrylate is 1:1.5~2.0, the esterification reaction temperature is 20~150℃, and the reaction time is 0.5~96h. In step 2), the molar ratio of the aromatic diester diacid to thionyl chloride is 1:1.5~3, the reaction temperature is -30~50℃, and the time is 1~48h; In step 3), the molar ratio of the aromatic diester diacyl chloride to the aromatic diamine is 1:0.8~1.2, the cooling temperature is -30~10℃, and the reaction time is 0.5~96h.

9. The preparation method according to claim 6, wherein: The resin solution described in step (3) has a high solid content, low solution viscosity and good viscosity stability. When the solid content is 10~45 wt.%, the solution viscosity at room temperature is 100~5500 mPa·s, and the solution viscosity change rate is less than 10% after being placed at room temperature for 7 days.

10. The use of a low-stress negative photosensitive polyimide resin according to any one of claims 1 to 5 in the preparation of multilayer metal interconnect circuit structures in wafer-level packaging and panel-level packaging.

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