Low-dielectric, nanoporous polyimide films prepared from PEO-POSS nanoparticles

Dielectric insulator materials that have low dielectric constants (k<2.5) are required as inter-level dielectrics to replace silicon dioxide (SiO2) in future semiconductor devices. In this paper, we describe a novel method for preparing nanoporous polyimide films through the use of a hybrid PEO-POSS template. We generated these nanoporous foams are generated by blending polyimide as the major phase with a minor phase consisting of the thermally labile PEO-POSS nanoparticles. The labile PEO-POSS nanoparticles would undergoes oxidative thermolysis to releases small molecules as byproducts that diffuse out of the matrix to leave voids into the polymer matrix. We achieved significant reductions in dielectric constant (from k=3.25 to 2.25) for the porous PI hybrid films, which had pore sizes in the range of 10-40 nm.