Tape casting and characterization of Li2.08TiO3-LiF glass free LTCC for microwave applications

Li2.08TiO3-LiF Glass-free Low temperature co-fired ceramic (LTCC) green tapes were prepared by tape casing technique. The rheology of the slurry was characterized using rheometer. The slurry exhibited pseudoplastic behavior. The sintering kinetics of the green tape was investigated using heating microscope. The sintering activation energy was determined to be ∼173 kJ/mol. The green tape could be densified at 900 °C/2 h. Microwave dielectric properties of the sintered tape were characterized in a split-post dielectric resonator using a network analyzer. The ceramic sheet with thickness of 0.11 mm demonstrated good microwave dielectric properties: εr = 22.4 and Q × f = 35,490 GHz. The cross sectional microstructure of the cofired multilayer stack was observed by scanning electron microscopy (SEM). The green tape demonstrated good chemical and shrinkage compatibilities with Ag electrode during sintering process. The thermal expansion coefficient and thermal conductivity of the ceramic is 22.4 ppm/∘C and 4.75 W m−1 K −1, respectively.