Probability of silicon fracture in molded packages [ICs]

The reliability of semiconductor devices in automotive environmental conditions requires optimized package design with respect to geometry, materials and manufacturing processes. Process steps at high temperatures can result in high package stresses at operating temperatures due to mismatch of thermal expansion coefficients of the package compound materials. Device failure may occur caused by failure modes, such as delamination of material interfaces or bulk material fracture. This paper addresses the predictability of silicon bulk fracture in microchips in electronic devices. The typical scatter of silicon strength data requires a probabilistic approach. Weibull theory is applied for the evaluation of the stress state and the computation of fracture probability in a microchip.