Influence of the trapezoidal cross-section of single and coupled inverted embedded microstrip lines on signal integrity

The influence of the shape of the cross-section of metallic conductors on the signal integrity (SI) behavior of on-chip interconnects is investigated. It is shown that, thanks to an advanced modeling technique based on the use of the Dirichlet to Neumann boundary operator, this influence can and must be accurately predicted. As a case study, a single inverted embedded microstrip (IEM) line and a pair of coupled IEM lines are considered. These structures are first described in terms of their per unit length (p.u.l.) resistance, inductance, capacitance, and conductance transmission line parameters. Second, a signal integrity study of such interconnects is performed in terms of time domain transmission (TDT) eye diagrams and crosstalk.