Effects of Extended Dwell Time on Thermal Fatigue Life of Ceramic Chip Resistors

The understanding of the effects of temperature cycling parameters, such as dwell and ramp times, mean cyclic temperature, and temperature range, on the fatigue life of solder interconnects is critical for qualification and reliability testing. After the solder achieves complete stress relaxation, a further increase in dwell time does not decrease the fatigue life of solder interconnects. Studies have shown that an increase in dwell time beyond a certain limit (10–20 minutes) has no effect on the fatigue life of eutectic tin-lead solder when cycled at peak cycle temperatures at or above 100°C. The duration of stress relaxation is longer in SnAgCu and SnCu solders than in eutectic tin-lead solder, resulting in higher creep damage accumulation and thereby reducing the fatigue life of solder interconnects. Experimental data for modeling of the effects of extended dwell time (beyond 60 minutes) on the temperature cycling reliability of tin-silver-copper solders is limited. In this study, forty 2512 ceramic ch...