Solder joint fatigue: comparison of hand soldering to vapor phase soldering on surface mounted components for aerospace applications

The solder fatigue life of hand-soldered joints was compared to vapor-phase-soldered joints by thermal cycling circuit cards populated with surface-mount components. Four package types were tested: two sizes of chip components (2512 and 0805), 14-pin gull wing flatpacks and 44-pin leadless ceramic chip carriers. Various process flows were correlated with solder joint reliability. The test samples were temperature cycled, over 7500 cycles from -30°C to +100°C for more than a year. Results of the temperature cycling indicate several interesting trends including some which are counter to expectations. Differences in component form and solder joint properties are likely explanations