Yield modeling of MCM assembly with flip-chip thermocompression bondings

Flip-chip connections using gold-to-gold, gold-to-aluminum, or gold-to-solder bondings or contacts enhanced by epoxy are low-cost alternatives to soldering. A yield model has been developed for flip-chip, thermocompression bondings. The model predicts the assembly yield as a function of forces and planarities of the end effector, bump height variations, bump geometries, mechanical properties corresponding to different materials and temperatures, and distribution patterns of bumps. The model calculates the deformation of each gold bump under different assembly conditions, and determines if the bonding is good, with a 15 to 45% range, or bad.<>