Novel methodology for 3D FEM modeling of wire bonding process by ball deformation reproduction

Computer Aided Engineering (CAE) is fundamental to guide design options in semiconductors industry. The increasing demand of early anticipation of manufacturing risks is leading to an improvement of CAE modeling on processes, focusing on Chip-Package Interaction (CPI). The integration of new materials, especially low-k dielectric, requires an increasingly deep understanding of thermo-mechanical stress affecting packaging processes and reliability. Moreover, stresses imposed by wire bonding process increase the risk of bond pad damage leading to cracks in the silicon structure. The aim of the presented work is the study of copper ball shape and its evolution during ball bonding phase to establish a new approach for the modeling of wire bonding. Finite Element Method (FEM) is developed and validated with experimental results obtained at different time intervals, on which the deformations occurred in the bonded copper ball has been measured.