Increasing the robustness for reliable packages by prediction of delamination by cohesive zone element simulation

Robustness of a package is often proven by performing temperature cycling tests. Thermo-mechanical stress caused by the mismatch of coefficients of thermal expansion (CTE) and temperature variations remains a major concern for the reliability of semiconductor components. This issue is usually addressed by exposing the component to a certain number of cycles, followed by e.g. scanning acoustic microscopy (SAM) to investigate delamination. Discussions about specific cycling conditions, e.g. using -65°C/+175°C instead of -55°C/+150°C for the minimum and maximum temperatures of the cycles or even using liquid-liquid cycling instead of air to air to speed up investigations [1], are often moot, because no real understanding of the effect of the cycling conditions on the component is available.