Silver Migration Model for Ag-Au-Pd Conductors

An acceleration model is presented for insulation failure between biased adjacent lands of a ternary Ag-Au-Pd alloy conductor paste on alumina substrates. The failure mechanism consists of silver diffusing in the form of tree-like dendrites through borosilicate glass overlays. Accelerated life test results, maximum likelihood estimation techniques, multiple linear regression analysis, and a previously proposed physical chemical model were used to derive the acceleration model. The activation energy of "dry" silver migration which was estimated to be 1.09 ±0.16 eV was in good agreement with previous studies of this Phenomenon.A comparison of reliability is made between this ternary alloy and a binary Ag-Pd alloy. The comparison shows the enhanced reliability of the ternary alloy, which may be due to the presence of gold in its formulation.