Reliability of Flip Chip Solder Bump Joints

Increasing complexities of the IC chips imply increasing demands on the chip packaging. Flip chip solder bump joints seem to provide the most logical solution for VLSI packaging. Thermal fatigue cycling studies of the joints were done and found to be extremely reliable with very low failure rates. Different factors affecting the fatigue lives were analyzed. Microstructural aspects of failure in the flip chip solder bump joints were studied using fracture surface and cross-sectional analyses. Formation and growth of Cu-Sn intermetallics and their effect on the failure of flip chip solder bump joints were studied.