Synergistic Effect of Fluorination and Molecular Orientational Order on the Dielectric Properties of Low-κ Liquid Crystal Polymer Films

Graft Architectured Poly(phenylene oxide)-Based Flexible Films with Superior Dielectric Properties for High-Frequency Communication Above 100 GHz

“…The rapid development of the fifth-generation communication era has led to an increased urgency and higher demands for high-performance dielectric polymeric layers in flexible copper-clad laminates (FCCL). , Since signal transmission speed and efficiency significantly depend on the dielectric constant ( D k ) and dielectric loss ( D f ) of circuit board materials, it is of great importance to develop dielectric polymeric layers with a low D k and low D f at high-frequency regime (>10 GHz). − Along with low dielectric properties, polymeric insulation layers must achieve other requisite properties including thermal stability, chemical stability, flexibility, and low water uptake to ensure the reliability of the FCCL working in the high-frequency regime . Up to now, various polymers including modified polyimide (mPI) and liquid crystal polymer (LCP) have been widely studied as polymeric substrates and dielectric layers for FCCL. − Despite significant progress being made on this front, achieving the aforementioned prerequisite properties still remains a major challenge. In detail, mPI, which has been widely used as electrical insulation layers, has high D f at high-frequency regimes and water uptake, limiting its usage in high-frequency applications. − While LCP demonstrates the potential for exceptional dielectric properties for FCCL in high-frequency regimes and reduced water absorption, the LCP film produced using traditional processing methods inherently showed anisotropic mechanical properties .…”