Benzocyclobutene‐containing Carbosilane Monomers as a Route to Low‐κ Dielectric and Low Dielectric Loss Materials

Abstract A benzocyclobutene (BCB) monomer containing carbosilane (CS‐BCB) was successfully synthesized from 4‐vinyl benzocyclobutene (4‐VBCB) and 3,6‐bis(dimethylsilyl)benzocyclobutene (3,6‐D(DMHS)BCB) by hydrosilylation in the presence of Karstedt's catalyst. As an improvement to the conventional synthesis method, the carbosilane is obtained in only two steps. In addition, this method avoids the use of halogens and Grignard reagents, which are expensive and environmentally damaging. After ring‐opening polymerization, the resultant cured CS‐BCB resin shows excellent thermal and dielectric properties; specifically, the 5 % weight loss temperature (T 5% ) is 435 °C, the dielectric constant (D k ) is 2.36, and the dielectric loss (D f ) is less than 10 −3 at 10 MHz. Thus, this polymer has enormous potential as a high‐performance electronic interlayer material.