DO WE NEED A PEM RELIABILITY MODEL?

摘要

Reliability prediction models for microcircuits have been a function of steady state temperature. Failure rates generated from accelerated temperature tests were extrapolated to predict system reliability at system use temperatures. This is now known to be completely inaccurate. Attempts are now being made to predict the reliability of plastic-encapsulated microcircuits(PAMs)based on accelerated temperature/humidity testing. Failure rates generated owing to corrosion failure mechanisms at these high stress levels are then extrapolated and used to predict system reliability at use temperature/humidity conditions. This paper discusses the fallacy of this approach. A new concept for assurance of PEM corrosion resistance is proposed. It will be shown that today's best commercial practice suppliers have already addressed the design, materials and processing issues of molded packaged microcircuits, and corrosion is no longer a mechanism of concern to the user.