Simulation models for signal integrity analyses extracted from computed tomography scans — A case study for high-speed interconnects

In this paper, a method for signal integrity (SI) analysis based on computed tomography (CT) scans is proposed. SI analysis based on state-of-the-art measurements can be difficult to perform if the structures of interest are on inner layers of multi-layer boards, are enclosed by IC packages or if appropriate contacts for measurements cannot be provided due to cost and space reasons. In contrast to that, the proposed method is based on accurate simulation models which are extracted from computed tomography scans that can be used in electromagnetic (EM) field simulators for computer aided SI analyses. Such CT based models include fabrication tolerances so that computed EM field simulation results have a good correlation with common measurements. Compared to state-of-the-art SI measurements, the use of EM field simulators significantly simplifies SI analyses since a suitable simulation setup can be chosen without the requirement of test fixtures or limitations for contacting the structures of interest. The methodology is demonstrated on high-speed interconnects which are especially well-suited for the method.