Effects of silver paste glass additive composition on co-firing behavior of silver conductor LTCC package

Low-temperature co-fired ceramic (LTCC) technology is widely used for the production of MCM-Cs, due to its high density, multi-function, and high-reliability packaging. The sintering temperature of LTCC is required to be below the melting point of the metal. Silver as the most commonly conductor, its co-firing compatibility with the glassy LTCC substrates needs to be evaluated. In this work, the effect of glass additive composition and characteristics on silver/LTCC co-firing behavior were studied. The lead borosilicate glass/ Al2O3 system was selected as the LTCC ceramic (America, Dupont 951PT). Bi2O3-B2O3-SiO2, PbO-B2O3-SiO2, and CaO-B2O3-SiO2 glass were employed as additive to prepare the silver conductor paste, which was printed on the surface of LTCC green tape and co-fired to fabricate the multilayer sample. The glass viscosity and wettability, the microstructures of silver film were studied. The results showed that the suitable viscosity and wettability of glass used in silver paste is critical to the sintering densification process even the glass additive is only 1 wt%. Adjusting the composition and characteristics of glass additives in conductor paste is one of the most important ways to achieve matching cofiring in a metal conductor/ ceramic multilayer structure.