Mixed fluid-heat transfer approach for VLSI steady state thermal analysis

During the development of integrated circuits, the thermal design aspect is crucial for their safe operation. The problem of junction overheating remains a major obstacle to the most required performances of electronic systems: increased operation speed and the components miniaturization. In both cases, those results are affected by junction overheating and associated induced higher thermal stress. The design of a reliable large and powerful processor requires whole device coupled fluid-heat transfer thermal analysis from junction to ambient. In this case, device electrothermal behavior is principally influenced by package geometry, junction structure, and physical heat source distribution. This paper presents a mixed fluid-heat transfer approach for thermal analysis of large VLSI devices. In this case, estimation of equivalent convection coefficient has become the major issue for device junction to ambient thermal analysis. Based on the FEM (finite element method), the approach combines fluid flow and heat transfer mechanism to predict, in general, IC working temperature. In addition, the effect of power density, position, heat sink characteristics, during thermal response is investigated. The new approach developed can be used for accurate rating of semiconductor devices or heat sink systems during large ASIC design. Results comparison between the proposed approach and traditional methods shows that this approach is effective as a design step.