Preparation and dielectric properties research of a novel kind of intrinsic silane-containing polyimide

Electronic crosstalk, signal propagation delay and loss on the redistribution layers (RDLs) have been increasingly serious along with the rapid development of wafer-level packing (WLP). Polyimide films with low dielectric permittivity (Dk) and low dielectric loss (Df) at high frequency are in demand imminently as interlayer materials. In this work, a novel kind of intrinsic silane-containing polyimide was designed and prepared by the reactions of 1,3-Bis(3-aminopropyl)tetramethyldisiloxane (APDS) and 4,4′-Oxydianiline (ODA) with 2,2-Bis(3,4-anhydrodicarboxyphenyl) hexafluoropropane (6FDA). The chemical structure of polyimide was studied by FT-IR spectrum and NMR and their dielectric properties and other performances were systematically analyzed. Results showed that the lowest Dk and Df of polyimide (6FDA/APDS) was 2.66 and 6 × 10−4 at 10 GHz. Furthermore, the dielectric permittivity and loss of silane-containing polyimide decreased with increasing the content of silane. The excellent dielectric properties were attributed to decreasing polarization and increasing the free volume of molecular chains when the silane was introduced into the molecular structure of polyimide. This work provided guidance for the intrinsic silane-containing polyimide with low dielectric properties.