The impact of packaging on the reliability of flip-chip solder bonded devices

An assessment of flip-chip solder joint reliability for a hybrid device assembly in which a zirconium-titanium-stannate dielectric ceramic chip is flip-chip bonded to a silicon circuit is presented. The device assembly was subjected to severe thermal cycling testing, involving up to 2000 cycles from -55 to +125°C. A range of device solder bond geometries and chip passivation structures were investigated, with devices packaged in both hermetic and nonhermetic enclosures. The results show that flip-chip solder bonds can be extremely reliable under such tests, with no failures being detected in devices that were hermetically packaged. Fatigue failures were observed in nonhermetically packaged devices. Extrapolation to likely operating conditions predicts field lifetimes of between 15 and 300 years