Power and signal integrity challenges in 3D systems

Power/signal delivering network for 2D systems comprising a package and an Integrated Circuit (IC) are design tasks that can be concurrently handled today. Design iterations can be locally carried out in each subsystem part without the need to modify the other one´s decisions. This is unfortunately not the case in 2.5D/3D stacked systems. Finer system integration technology, either via Through Silicon Stack (TSS) and/or Through Silicon Interposer (TSI), involves tighter evaluation of the coupling effects in the system-wide PDN impedance and Signal Integrity (SI) characteristics. If these interactions are not properly accounted early in the design cycle, undesired design loop iterations, affecting design productivity is possible. Therefore, new tools and flows incorporating abstracted physical information of the PDN and signal interconnect stack architecture are needed for early design exploration. This paper elaborates on the problems, tool flows and methods necessary to address these challenges for 2.5D/3D stacked systems.