Transient thermal analysis applied to an IC package

A transient thermal study was performed by experiment and CFD (Computational Fluid Dynamics) simulation on an IC (Integrated Circuit) package to predict real time thermal responses. The experiment was conducted using a JEDEC standard 2s2p test board and a thermal test die in a closed loop wind tunnel. The transient thermal behavior of the IC package was captured with a LabView program and a data acquisition system. A three-dimensional half model was developed with Flotherm3.2 CFD software and solved for the same boundary conditions of the experiment. Detailed geometrical models of die, underfill, bumps, substrate, socket, pins and PCB were simulated as solid cuboids. The model was validated and achieved a 92% agreement with experimental results. The simulation model was further used to predict the thermal response subject to various boundary conditions such as application of burst power and with a heat sink. The validated methodology was then applied to a live organic pin grid array package (OPGA) and its transient characteristics were determined for computer cold start process. An agreement of 90% was achieved between the numerical result and experiment data.