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The steady-state thermal performance of the 164-lead flip chip plastic ball grid array (FC-PBGA) under low to moderate convective air cooling conditions has been simulated through finite element (FE) methods and computational fluid dynamics (CFD) methods. Experimental measurements taken with thermal test vehicles of this package were used to validate the simulations. Packages with three different substrates were investigated. Package performance has been presented in the form of a linear relationship between the normalized junction-to-ambient thermal resistance (OJA) versus the normalized board-to-ambient thermal parameter ($,BA). Results cast in this form represent a first-order thermal figure of merit for packages. Such a figure of merit can be used to rank in a consistent manner the thermal performance of different package types.A CFD study was performed to investigate the thermal performance of the package on a central processing unit (CPU) module assembly. A parametric study was performed to investigate the die temperatures as a function of thermal interface materials and heat sink configuration. sink solutions were studied. The results of those board-level simulations give a reasonable indication of how the package would perform in a workstation environment.Advances in integrated circuit performance have driven the development of high performance and high input/output (YO) packages such as the ball grid array (BGA). Advantages of the BGA over comparable leaded or through-hole packages include high U 0 in relation to its printed wiring board (PWB) footprint, '

We present a novel modeling methodology for optimizing the mass of aluminum-extruded heatsinks for cooling desk-top microprocessors. The two-stage study aims at reducing mass of an aluminum-extrusion heatsink by taking advantage of the existing thermal resistance margin. In Stage 1, we investigated several possible combinations of base shapes to minimize the mass of the base region. Base shape is optimized by dividing the base volume into several blocks of equal width, with the objective of progressively minimizing the mass of the peripheral region while shaping the middle region to minimize spreading resistance. Three base shape profiles—namely, wedge, semielliptical, and flat top—were selected for further study. In Stage 2, a thorough base, fin thickness, and fin count study was carried out by mathematical optimization. The result of this optimization exercise was a 30% reduction in the heatsink mass. The degradation in thermal resistance of the mass-reduced design is within the acceptable margin and meets microprocessor product specifications. Results are experimentally verified by testing four different competing samples having comparable optimized masses.