Low temperature sintering of BaTi₄O₉-based middle-k dielectric composition for LTCC applications

Effect of glass addition on the low-temperature sintering and microwave dielectric properties of BaTi₄O₉-based ceramics were studied to develop the middle-k dielectric composition for the functional substrate of low-temperature co-fired ceramics. When 10 wt% of glass was added, sufficient densification was obtained and the relative density more than 98% was reached at the sintering temperature of 875°C. The microwave dielectric properties were k = 32, Q × f = 9000 GHz, and t _cf = 10 ppm/°C. As the added amount of glass frit with base dielectric composition, phase changes from BaTi₄O₉ to BaTi₅O ₁₁ and Ba₄Ti₁₃O₃₀ was observed, which result in the modification of microwave dielectric properties.