Low temperature curing polyimides with covalent-boned 5-aminobenzimidazole

Polyimides (PIs) with remarkable mechanical, thermal, dielectric properties have been extensively employed in electronic package of integrated circuit industry. However, PI is imidized at high temperature (>350 °C) traditionally, which limits its application in thin-film transistor and fan-out wafer level package (FOWLP). In this work, active curing catalyst of 5-aminobenzimidazole is introduced in covalent bond to get a low temperature curable polyimide with superior comprehensive properties. The results prove that PI-3 can be imidized completely at 200 °C in 2 h and the imidization index could be as high as 1.03. Besides, the PI films exhibit excellent thermal stability of which the temperature for 5% weight loss is as high as 526 °C and glass transition temperature is 428 °C which is obtained by dynamic mechanical analyzer. Moreover, the tensile test shows the tensile strength of PI-3 is 91 MPa and elongation at break is about 15%. All these results prove the superior performance of the low temperature curing PIs, showing great potentials in the advanced package in the FOWLP and the others.