Reliability assessments and designs for fine pitch flip chip packages with Cu column bumps

Study of the UBM to copper interface robustness of solder bumps in flip chip packages

“…For a robust design it is important to assess each step for its contribution. Since the overall system is complex an often approach is the simulation of the package to identify points of highest stress levels and subsequent optimisation of design and processes for overall stress reduction [2,10,11].…”