Tailored Ultralow Dielectric Permittivity in High-Performance Fluorinated Polyimide Films by Adjusting Nanoporous Characterisitics

Abstract

To acquire advanced nanoporous fluorinated polyimide (F–PI) films with low dielectric permittivity applied in microelectronic fields, as a feasible tactic, the SiO2/F–PI nanohybrid films were first synthesized to employ an in situ polymerization process by controlling the dispersion of SiO2 nanoparticles in polymer and the chemical reaction of monomers composed of F–PI. Then, the removal of SiO2 nanoparticles from the SiO2/F–PI nanohybrid films by HF acid etching gives rise to the amount of nanopores with a diameter of about 40 nm in the porous F–PI films, which can be confirmed by observing TEM image results. The relationship between the microstructure of the nanoporous F–PI films and the properties, including relative dielectric permittivity, thermal stability, contact angles, and mechanical strength, was discovered. The relative dielectric permittivity of the nanoporous F–PI films was decreased to 2.45 while the films still displayed good mechanical properties and thermal stability. So this type of advanced nanoporous F–PI films brings a very potential application as alternative dielectric layers in the future microelectronic technology.