Tuning the Curing Temperature of Polyimide Precursor: Ploy Amide Ester

Photosensitive polyimide (PSPI) is a kind of dielectric material with dual functions of photosensitivity and heat resistance, which is applied in redistribution layers (RDLs). However, with the development of miniaturization of electronic devices, low curing temperature (<250°C) and low CTE are great in demand, as for the wafer warp in packing process. Herein, we report a kind of PAE, which was synthesized from 4, 4'-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) via the poly-iso-imide intermediates, the esterification rate is around 60% which was calculated by ¹ H-NMR. With an addition of quinoline at amount of 10%(wt.), the imidization index of the PI cured at 300°C is 98.1%, in comparable with the comparable PAE (no quinoline addition) cured at 350°C. Besides, the mechanical and thermal properties were also invesgated. The PI with quinoline cured at 300°C also exhibit high tensile strength, high Young's modulus and low coefficient of thermal expansion (tensile strength of 120 MPa, modulus of 3.05 GPa and CTE of 38.9 ppm/K) compared to PI cured at 350°C (tensile strength of 140 MPa, modulus of 2.99 GPa and CTE of 33.3 ppm/K). This research extended the range of substrates in quinoline promoted low temperature curing and will have a broad application prospect.