A Modeling Method For The Study Of Thermomechanical Behavior Of High Density Interconnect (HDI) Vias

The thermomechanical behavior of High-Density Interconnect (HDI) vias has been numerically modeled taking into consideration the process-induced residual stresses. In this work, a two-step global-local scheme is implemented. The global model enables the computation of displacements, while the local model enables the computation of strains and stresses in the fine via structures. As the dimensions of the via structures are several orders of magnitude smaller than the dimensions of the HDI structure, a global-local modeling scheme is necessary for computational efficiency without losing accuracy. The models developed in this work can be utilized up-front in the design stage to select material, geometry, and processing parameters prior to undertaking extensive prototyping and reliability testing. Results from the global model used as input to the local model are validated using laminated plate theory analysis. Preliminary predictions of thermal fatigue failure of vias are also provided and are compared to experimental data.