Enhanced thermal conductivity and mechanical performance of CaO–B2O3–SiO2 glass ceramic with AlN addition for LTCC applications

As electronic devices with high integration and reliability are developed, the need for electronic packaging materials with good thermal conductivity, dielectric properties, and mechanical properties has increased. In this study, a CaO–B2O3–SiO2 (CBS) glass ceramic with added aluminium nitride (AlN) was prepared via tape casting and solid phase sintering. The sintering behavior, phase compositions, microstructure, thermal conductivity, mechanical properties, and dielectric properties of the material were investigated. The addition of AlN greatly enhanced the thermal conductivity and improved the mechanical properties of the composite. The CBS/AlN composite with 40 wt% AlN sintered at 860 °C for 20 min exhibited excellent performance with a thermal conductivity of 6.23 W/(m⋅K), a coefficient of thermal expansion (CTE) of 6.11 ppm/°C, a flexural strength of 212.6 MPa, a dielectric permittivity of 7.2–7.36 with a relatively low dissipation factor of 0.0003–0.002 (1 kHz–10 MHz), and a weak temperature dependence of the dielectric permittivity. Moreover, the excellent chemical compatibility with silver made such CBS/AlN composites a promising material for electronic substrate applications.