Crystallization and dielectric properties of low temperature dielectrics containing Li2O filler

Crystallization and dielectric properties of typical low temperature co-fired ceramics (LTCC) consisting of calcium zinc aluminoborosilicate glass and Al2O3 filler were investigated by substituting the Al2O3 filler partially with Li2O at the levels of 2–10 wt%. Depending on the content of Li2O, densification was found significantly affected by early crystallization that resulted from the formation of unexpected crystalline phases including LiAlSiO4, Ca2SiO4, LiAlO2, and LiAlSi3O8. The effect of hindering sintering via earlier crystallization became enormous regardless of firing temperature when >5 wt% Li2O substitution occurred. It was observed that the substitution of 2 wt% Li2O for Al2O3 was beneficial in producing promising performance at the low temperature of 750 °C, which can be highlighted with k ∼ 8.7 and tan δ ∼ 0.009 at 1 MHz.