Fabrication and characterization of glass-ceramic+Al/sub 2/O/sub 3/ composition for LTCC(low temperature co-fired ceramic)

The glass+ceramic compositions for LTCC dielectric materials have been investigated. The glass+ceramic mixtures consist of cordierite based crystallizable glass (MgO-Al/sub 2/O/sub 3/-SiO/sub 2/-GeO/sub 2/), Al/sub 2/O/sub 3/ as a filler and zinc borate as a sintering additive. The GAZ series had superior characteristics to GA series. Densification was almost finished in GAZ series (glass+Al/sub 2/O/sub 3/+zinc borate) after sintering at 850/spl deg/C, while in GA series (glass+Al/sub 2/O/sub 3/) it was finished after sintering at 900/spl deg/C. Especially the loss tangent of GAZ series was much lower than that of GA series. GAZl sintered at 900/spl deg/C showed promising microwave properties having the Qf (quality factor/spl times/frequency in GHz) of 5594.9 and a dielectric constant of 5.92 at 8.4 GHz.