Holistic Reliability: Accelerated Testing Of Metallization

Understanding metallization reliability is crucial as two-thirds of all defects detected in fielded modules is directly related to cell and metallization problems. This coupled with the reduction in metallization laydown by 70% over the last 5 years poses a risk to long term module reliability. A critical issue is separating intrinsic vs. extrinsic effects on failure modes seen under testing of silver paste durability. We have varied the flux used in soldering of the ribbons to the cell and seen differentiation in durability. From these learnings we have then tested different silver pastes under damp heat and pressure cooker testing. Finally, we present a series of aged adhesion with temperature cycling to develop accelerated testing of adhesion.