Effect of AlN addition on phase formation in the LTCC with Al2O3/AlN biphasic ceramics based on BBSZ glass

The miniaturization, integration and portability of electronic products place higher requirements on the thermal conductivity of electronic packaging materials. In this paper, Bi2O3-ZnO- B2O3-SiO2 (BBSZ) glass was used as the glass phase, and Al2O3/AlN was used as the biphasic ceramic phase. Low temperature co-fired ceramic (LTCC) materials with high thermal conductivity were prepared by tape casting and solid phase sintering. The crystal phase composition, microstructure, thermal conductivity, thermal expansion and dielectric properties of LTCC were studied. The results show that in the BBSZ/Al2O3/AlN LTCC materials, nano-needle-shaped zinc-aluminum spinels are formed. When the AlN content is 20 wt%, the thermal conductivity is 5.983 W/(m·K), which is the highest. LTCC material with 20 wt% AlN has excellent dielectric properties (εr = 4.4408, tanδ = 5.3 × 10−3 at 20 GHz) and a thermal expansion coefficient (CTE = 4.63 ppm/K) matched well with silicon. BBSZ/Al2O3/AlN LTCC materials can be used in 5G communication and other applications.