LTCC tapes based on Al2O3-BBSZ glass with improved thermal conductivity

A novel low temperature co-fired ceramic (LTCC) composition consisting of 40 wt% Al2O3-60 wt% BBSZ (35Bi(2)O(3):32ZnO:27B(2)O(3):6SiO(2)) fireable at 850 degrees C has been developed. The XRD study of the sintered composite shows the presence of Bi24Si2O40 and ZnAl2O4 secondary phases. The bulk samples sintered at 900 degrees C has dielectric constant (epsilon(r)) of 11.3 and loss tangent (tan delta) of 0.001 at 1 MHz. Tapes of the composite have been casted on Mylar (R) film and the green tape has a surface roughness of 299 nm and tensile strength of 0.1 MPa. Upon sintering the tapes showed an epsilon(r) of 10.9, tan delta of 0.009 and temperature coefficient of dielectric constant (tau(epsilon)) of 487 ppm/degrees C at 5 GHz, which are suitable for practical hybrid device applications. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.