A Comparative Study on Reduced System Thermal Models for Transient Simulations

Semiconductor packaging and interconnect technologies today rely more and more on system solutions with increased modularity and functionality. Profound understanding of the heat transfer mechanisms at any steady or transient loading is essential for optimizing the new systems designs. Detailed transient thermal analysis conducted with commercial computational fluid dynamics (CFD) tool is time-consuming and laborious especially when the analysis scope ranged from package, to handheld device, to laptop, even a single parameter optimization requires lengthy simulation run time. Reduced system models are simple and efficient for quick thermal analysis especially during early design stages, where board layout, CPU powermap, and system geometry details are not completely available. This quick analysis helps to decide new architecture level changes in the early stage of design.In this paper, zoom-in transient model i.e. dual-region approach is proposed for reducing the computational time with almost same accuracy compared to the full detailed model. In this approach, one region is drawn across the area of interest i.e. die or full package or some part of system and enveloped by another region to calculate the local boundary condition over the surfaces. In the baseline study, the proposed model reduces computational time 70-80% with a marginal accuracy trade-off based on the size of regions across the area of interest. The zoom-in transient model results i.e. temporal plot of junction temperature and burst time are compared with the available different compact approaches including the unit-level and Docea models for the detailed system level transient simulation.