Thermal and Moisture Stresses in Plastic Packages

Increased package density and reliability expectations require a better understanding of the mechanical behavior of plastic packages under process and use conditions. This chapter reviews potential failure modes and a combined analytical/experimental approach developed under ESPRIT project 5033—PLASIC for stress analysis in plastic packages. This includes (1) a failure criterion for moisture-induced stresses; (2) a finite-element approach for thermal stress analysis; and (3) a piezoresistive technique for stress measurements and model calibration. The latter is applied to the particular problem of metal line displacement at the surface of a silicon die.