A low dielectric constant material synergized by calix[4]arene and benzocyclobutene units
The rapid development of the semiconductor industry puts forward higher requirements on the properties of insulating dielectrics. As a supramolecular compound, calix[4]arene has a unique cavity structure, showing potential for a low-k material. We herein reported a novel strategy to functionalize the 4-tert-butylcalix[4]arene with different numbers of benzocyclobutene (BCB) units (2 or 4) and spacers (–(CH2)3– or –(CH2)6–) by sequential substitution and hydrosilylation reactions. These precursors can be cured under heating to form a crosslinked film. The optimized curation condition was screened by differential scanning calorimetry (DSC) measurement. Combining with a comparison experiment using a precursor with calix[4]arene but without BCB units, the wide-angle X-ray scattering (WAXS) pattern and thermal analysis provided solid evidence that the high thermal stability of the film (glass transition temperature (Tg) > 110 °C, 5 wt% loss temperature >367 °C, and the coefficient of the thermal expansion < 87.88 ppm °C−1) was majorly contributed by calix[4]arene, while the excellent dielectric properties (the lowest dielectric constant Dk = 2.23 and the average dielectric loss Df < 1.5 × 10−3) were synergistically affected by both calix[4]arene and BCB units. The static water contact angle was mostly higher than 100° and high hydrophobicity was confirmed, which can meet the additional requirements in practical application. The low dielectric constant synergized by calix[4]arene and the BCB unit is hoped to aid in developing a novel strategy for low-k materials.
危险品化学品经营许可证（带存储）