Impact of Impedance Change Caused by Bonding Wire Connection on Signal Transmission

Bonding wires are widely used in microwave circuits and chip packaging. Due to the high frequency of signals transmitted by modern communication circuits, any structural discontinuity may cause signal reflection. Bonding wires are one potential source of such effects and their impact on signal transmission performance is examined in this study. In the present work, based on the size and material characteristics of a sample circuit board with bonding wires, a 3D electromagnetic numerical calculation model was developed. The voltage standing wave ratio for various numbers of bonding wires between two connection points was studied. In addition, a corresponding circuit model was developed and the equivalent inductance for different numbers of bonding wires was calculated. Both the electromagnetic field model and the circuit model results were validated using experimental tests. Using these models, the impact of impedance changes resulting from different numbers of bonding wires on the integrity of both analog and digital signals was analyzed.