Sintering behaviors, microstructures and dielectric properties of CaO-B2O3-SiO2 glass ceramic for LTCC application with various network modifiers content

CaO-B 2 O 3 -SiO 2 (CBS) glass ceramic with various glass network modifiers were synthesized to develop a kind of material sintered at low temperature for multi-layer ceramic substrates. The influence of double alkali metal oxides (Na 2 O and K 2 O) on sintering characteristics, microstructures and dielectric properties of CBS glass ceramic were investigated. XRD analysis showed that the major crystalline phase was β-CaSiO 3 and CaB 2 O 4 , and the strength of the peak increased with the addition of network modifiers. DSC curve revealed that the process of crystallization and softening were obviously affected. SEM photographs exhibited that the microstructures were composed of amorphous phases, pores and crystalline phases. FTIR showed that the additives changed the continuity of CBS glass structure. An appropriate amount of Na 2 O and K 2 O additives could significantly improve the sintering characteristics and dielectric properties. CBS samples with 1.5 wt% (Na 2 O + K 2 O) sintered at 850 °C for 15 min presented the best performances with the bulk density of 2.53 g/cm 3 , ε r  = 5.94 and tan δ  = 1.22 × 10 −3 at 10 GHz.