Accelerated stress testing methodology to risk assess silicon-package thermomechanical failure modes resulting from moisture exposure under use condition

IC components are exposed to moisture and thermal cycles during chip-package-board assembly and in their end use conditions. Moisture exposure influences the mechanical integrity of silicon backend dielectrics, assembly/packaging materials and packages. Reliability performance under accelerated stresses that simulate use conditions are often a critical factor in choice of materials, processing options and design rules. A complete assessment of the cumulative environmental exposure from chip-package assembly, shipment/storage, board system assembly, through end-customer use is required to guarantee product performance and reliability. This paper will detail these end user environments and use failure mode/mechanism specific acceleration models to develop accurate accelerated life testing plans and requirements. These requirements will then be compared to JEDEC standards based requirements and a need for re-calibration of these standards to more appropriate temperatures and stress durations will be highlighted.