Dynamic Warpage Analysis of QFP Packages During Soldering Reflow Process and Thermal Cycle

The mechanical reliability of thin plastic packages during soldering reflow process on circuit board and thermal cycle becomes one of the most critical aspect in device mounting and operation. When a package is subjected to thermal loadings, deformation and deviation from an ideal uniform planar flatness usually result. Package warpage leads to thermo-mechanical issues at those sites of weak adhesion in the structure. The estimation of warpage is necessary for increasing package reliability. This paper deals with in-situ characterization of temperature-induced package warpage by adopting fringe pattern projection principle. The experimental analysis allows to evaluate real-time dynamic warpage at different target temperatures. In addition, numerical modeling is employed to identify the most critical material interface when a package is subjected to thermal loads. Simulation results are in good agreement with standard reliability trials on packages mounted on board.