Evaluation of long time stability of solder joints on Ag thick film conductors on Al2O3

The long time stability of solder joints on Ag-based thick film pastes has been studied. Therefore shear strength, electrical resistance, temperature coefficient of resistance (TCR), optical inspections of solder surface and cross section analyses have been performed. Samples of 1206 and 0805 SMD-components mounted with SnAgCu, SnPbAg, SnBi and SnCu on Ag/Pd or Ag/Pt conductors were prepared. To detect the influence of intermetallic phase growth, high temperature storage according JESD22-A103C at 150°C (125°C for SnBi-solder) up to 500 h has been applied. Shear fatigue life of the interconnection joints was studied with temperature cycling according JESD22-A104D between +125°C/-40°C for up to 1000 cycles. Differences in shear fatigue and electrical characteristics will be evaluated and discussed.