Effect of 3D stack-up integration on through silicon via characteristics

Silicon interposers are a key component of 3D integration and the parasitic effects due to vias in interposers are known to contribute an important part to their overall electromagnetic properties. Therefore, the modeling has been extensively studied in recent years with numerous boundary conditions, port definitions, and further assumptions regarding the modeling of metallizations and finite planes. Most studies assume that certain port definitions can be applied such that the vias can be modeled independently of their electromagnetic environment. Independent modeling of the system parts increases in general the numerical efficiency but also raises questions with regard to its validity. To study the impact, interposers inside different stack-up environments up to 100 GHz are simulated. This paper presents scattering parameters at well-defined coaxial ports from full-wave simulations. The results are also compared to results from a multi-conductor transmission line model and to results from a physics-based via model. Systematical variations are carried out which enable an assessment of the applicability of the segmented modeling approaches.