Impact of the Configuration of Ground Vias on the Performance of Vertical Transitions Used in Electronic Packages

The ground vias are used to interconnect the different ground planes existing in a package structure, but also to prevent the propagation of parasitic modes like the parallel-plate mode inside the structure. From a signal integrity perspective, these parasitic modes degrade and limit the performance of a package since they introduce undesired resonances in the electrical response of the structure. Thus, the distribution of the ground vias is of great importance in the design of advanced packages. Using full-wave simulators, we have observed the distribution of the electric and magnetic fields as a high-frequency signal propagates through vertical transitions surrounded by ground vias. The information from the distribution of fields and the corresponding S-parameters were obtained from simulations for different configurations of ground vias in a vertical transition; these are the bases of the paper. The purpose of the presented analysis is to understand the relationship between the frequency at which the resonances associated with the propagation of parasitic modes occur and the configuration of the ground vias.