New concerns about integrated circuit reliability

Accelerated-stress life testing is widely used for the purpose of controlling process aberrants which could supply whole lots of high-failure-rate parts. Accelerated-stress conditions are also used for screening purposes to reduce or eliminate early failures. But, a new reliability consideration results from the fact that many electronic systems which use large numbers of integrated circuits are now being shipped directly from the factory to the final customer, without requiring lengthy installation and test periods. Infant-mortality failures, which were formerly absorbed in the installation period by the equipment manufacturer, are now seen by the user, and the measurement and control of these failures becomes more important. Although these failures include a large variety of failure mechanisms, some temperature dependence is apparent (0.25-0.4 eV) and time-to-failure parameters can be identified so the specific conditions of device or equipment burn-in, with respect to time and stress, can be quantified and optimized. Failure-rate plots are given for the infant-mortality period. They show that failure rates of multiple-device-chip assemblies can be predicted from known failure-rate plots of individual chips.