Dielectric behavior and film surface structure in fluorinated aromatic polyimide films

摘要

Two series of fluorinated aromatic polyimides were developed as novel dielectric packing materials with potential applications in microelectronics. These polyimides were synthesized based on diamines or dianhydrides containing (trifluoromethyl)phenyl groups at the 2- and 2'-positions of biphenyl units. Powder samples displayed excellent solubility in common organic solvents, and film samples were tough, flexible, transparent and thermally stable with low permittivities, moderately low CTEs, and high T_gs. These polyimides exhibited multiple relaxations in dynamic mechanical and dielectric analysis. The optical birefringence and the dielectric relaxation anisotropy characterized the structural in-plane orientation within these amorphous polyimide films.