Influence of process and stress conditions on microstructure and failure mechanisms of second level sintered Ag joints

Silver sintering of large areas to join components or substrates on the second level has been the subject of the investigations of this paper. Simplified test vehicles made of two metallized metal sheets were used. One sheet was made of an Aluminium alloy (AlMg3) and the other one of Copper in order to have different coefficients of thermal expansion. The commercial Ag sinter paste was applied using stencil printing whereby different stencil thicknesses were used. Process parameters for the printing process as well as for the sintering process have been identified with which high quality large area silver sinter joints could be produced. Thermal shock tests (-55/+125 deg C) were performed revealing that even in the worst case the cracked area was only approximately 6% after 5000 thermal cycles.