Abstract

VeCS which stands for vertical conductive structure is an advanced design and process approach to improve BGA, connectors signal/power integrity (SI/PI), and routing density. The VeCS has conductive traces surrounded by a conductive shield. Because the VeCS is a semi-coaxial structure, it has similar advantages that coaxial structures have. The first advantage is well-managed characteristic impedance along with vertical. The signal always references the metal shield, thus the characteristic impedance does not vary vertically. Another advantage is low loss. The loss can be from both insertion and return losses. The VeCS has a lower return loss compared to PCB vias, which improves the loss. As scalable models for the via have been introduced, this paper also proposes a scalable model for the VeCS. The scalable model is an analytical approach to analyze the VeCS and includes cascaded RLC blocks. 3D electromagnetic (EM) simulations provided the insertion losses depending on the height of the VeCS, and optimization algorithms established the scalable model. The optimization algorithms include simulated annealing (SA) to find the equivalent circuit and linear regression to generalize the equivalent circuits depending on the height. In conclusion, this paper introduces the VeCS and proposes its scalable model to efficiently analyze and design the VeCS. The 3D full-wave simulation shows that The VeCS has better electrical performances in the time and frequency domain.