A comprehensive surface mount reliability model covering several generations of packaging and assembly technology

An extensive set of surface mount reliability data gathered between 1984 and 1992 has been integrated in a single design-for-reliability tool, the comprehensive surface mount reliability (CSMR) model. This analytical/empirical model fits 28 accelerated test datasets with a correlation coefficient of 0.97, a significant improvement over a correlation of 0.40 over the same database for the existing figures of merit. The new solder joint life prediction capability spans test conditions with a wide range of frequencies and temperature limits and covers three orders of magnitude in cyclic life. The validity of the model has been verified for evolving families of components, substrates and assembly technology, including 0.5-mm pitch Alloy 42 thin small-outline packages (TSOPs) and large, 25-mil pitch devices. The innovative features of the CSMR methodology are presented, and its application is is illustrated for several design examples. Important benefits of the model are more accurate surface mount (SM) reliability predictions and less conservative design decisions than from previous models.<
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