Fluorinated Benzocyclobutene-Based Low-<i>k</i> Polymer at High Frequency
Fengping Liu, Jing Sun, Qiang Fang
Abstract
Through the Heck reaction, a fluorinated monomer with cross-linkable substituted vinyl and benzocyclobutene groups has been successfully synthesized. Treating this monomer at elevated temperatures results in a cross-linked polymer, exhibiting favorable dielectric properties with a permittivity (Dk) of 2.53 and a dielectric loss (Df) of 2.18 × 10–3 at a frequency of 5 GHz. Such good dielectric properties are maintained, even when the polymer is immersed in boiling water for up to 96 h. The polymer also exhibits good thermal stability with a glass transition temperature (Tg) of 263 °C as well as a coefficient of thermal expansion (CTE) of 79 ppm/°C. These data manifest that the monomer is appropriate for its use as a precursor for encapsulation resins for the manufacture of devices used in the field of high-frequency communication.