Analytical Models for Calculating the Inductances of Bond Wires in Dependence on their Shapes, Bonding Parameters, and Materials

Abstract

Novel analytical models for accurately and efficiently calculating the inductances of bond wires in dependence on their shapes, bonding parameters, and materials are derived. For verification, the inductances of bond wires having different geometrical dimensions and material properties were analytically calculated using our proposed models, and compared to those numerically extracted using Ansys Q3D. An excellent correlation was obtained, with a maximum discrepancy of approximately 1%. These models can be applied to rapidly predict the impact of the bonding parameters and their process variations right at the beginning of the design process. For example, using the models, we could predict within seconds that the loop inductance of a ground-signal bond wire configuration can be reduced by approximately 14%, 19%, or 37%, respectively, if the loop height, pitch or the distance between the bonding positions is reduced by 50%. To quantify the impact of the reductions in inductance on realistic signal transmission characteristics of the wires, we fabricated and measured bond wire interconnects up to 40 GHz.