Decoupled Package-On-Package thermal characterization

Thermal characterization of a package-on-package (PoP) presents a challenge due to the variation in stacking configurations. Currently available characterization methods as outlined in the JESD51 standard cannot predict die temperatures for packages with more than one die, let alone multiple stacked packages. A model is presented to predict die temperatures for PoP by combining individual resistor networks using a Delphi network modeling approach. Data from experimental tests were used to confirm the accuracy of a finite element analysis (FEA) based conduction model for an assembled PoP under varying power combinations. Separate FEA models for top and bottom packages were used to extract resistance values for two different resistor networks. These network models were combined to predicted die temperatures with a difference less than 7% when compared to the FEA model of the PoP.