Layer assignment for reliable system-on-package

The routing environment for the new emerging mixed-signal system-on-package (SOP) technology is more advanced than that of the conventional PCB or MCM technology - pins are located at all layers of SOP packaging substrate rather than the top-most layer only. We propose a new interconnect-centric layer assignment algorithm named LA-SOP that handles arbitrary routing topologies and produces near optimal results. The contribution of this work is threefold: (i) modeling of the SOP routing resource, (ii) formulation of the new SOP layer assignment problem, and (iii) development of a fast and novel algorithm that considers the various design constraints unique to SOP. We review various approaches for the PCB, IC and MCM algorithms and investigate their applicability to the SOP model. Our related experimental results demonstrate the effectiveness of our algorithm LA-SOP.