Sintering Behaviors, Microstructures, and Dielectric and Thermal Properties of CBS/Mg2SiO4 Composite for LTCC Application

The (1− x )CaO-B 2 O 3 -SiO 2 (CBS)/ x Mg 2 SiO 4 composites were prepared and the influence of CBS crystallizable glass content on the sintering properties, dielectric properties, and thermal properties of the composites were investigated. The primary crystal phases in the CBS/Mg 2 SiO 4 composites were CaMgSi 2 O 6 and CaB 2 O 4 . An appropriate amount of Mg 2 SiO 4 reduced the crystallization temperature of the composite. For x  = 0.30, a sintering temperature of 890°C with a holding time of 60 min resulted in a bulk density of 2.645 g/cm 3 , dielectric constant of 6.6, and dielectric loss of 2.54 × 10 −3 at 10 kHz. Prolonged holding time promotes grain growth; when extended from 60 min to 180 min for x  = 0.30, the permittivity increased from 6.5 to 6.6 and Q × f increased from 10,100 GHz to 15,700 GHz when x  = 0.30 at 13 GHz. The CTE of 70 wt.% CBS + 30 wt.% Mg 2 SiO 4 composite was 9.5 ppm/°C, which approached the value of a circuit board for a ceramic ball grid array package (CBGA).