Test vehicle to characterize silicon to organic flip chip package thermomechanical interactions

The thermomechanical interaction of organic flip chip assembly is primarily driven by the coefficient of thermal expansion (CTE) mismatch between die and package. This, in addition to emerging constraints like mechanically weaker silicon inter-layer dielectrics, lead free assembly and tighter bump pitch, etc., significantly increase the assembly yield and reliability challenges. Electrically sensitive short loop assembly test vehicles with representative product design features provide quick data turn and more coverage than live products to address these interconnect concerns. Yield and reliability data plus stress modeling and experimental measurements from assembly test vehicles highlight the importance of silicon and package test structures to understand die to package CTE mismatch induced stress, helping to identify the weak links in packaging architecture from materials, process and design.