Low Temperature Cofiring and Dielectric Properties of Ca-Doped Al2O3/K2O3–B2O3–SiO2 Composite Ceramics for LTCC Applications

Al2O3/K2O3–B2O3–SiO2 low temperature cofired ceramics (LTCC) dielectric materials doped with CaCO3 were prepared by using a solid-state reaction. The microstructure and dielectric properties of Al2O3/K–B–Si borosilicate, together with the effects of Ca doping, were investigated. A new material system candidate of Al2O3/KBSiO borosilicate doped by Ca was achieved after sintering at 880°C, which presents an optimized performance on dielectric properties with a permittivity ϵr < 8 and dielectric loss tan δ ≤ 0.002 and excellent stabilities across very broad frequency and temperature ranges. Most importantly, the initial results have also indicated that the new dielectric composite material is well compatible with the existing LTCC process, suggesting a considerable potential for practical LTCC applications.