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Thermal enhancements for a plastic-ball-grid array interconnect technology: computational-fluids dynamics modeling and characterization for low-velocity air-cooling

This paper presents various thermal management options available for plastic-ball-grid array (PBGA) interconnect technology, as they apply to low-end/midrange computer products. A series of experimental and computational studies were completed to investigate the thermal management options available for a high-power 119 (7/spl times/17 ball array) PBGA component. As a change in packaging technology was not an option, thermal enhancements were limited to increasing the package substrate conductivity and/or the addition of an attached heat sink (four distinct heat sink options were investigated). To solve the conjugate heat transfer problem, three-dimensional computational-fluid dynamics (CFD) models were developed for a single 119 PBGA (plastic-ball-grid-array) package mounted to a printed-circuit board (PCB) forced air-cooled (0.5 to 4 m/s). The representation of the package, material, PCB, boundary conditions, and solution grid will be presented. Experimental data was obtained for a single-component mounted to two printed circuit board compositions: (1) a single-signal layer, and (2) a two-signal/two-plane (2S/2P). In addition, a limited parametric study to investigate the effect of substrate material thermal conductivity (from the base level of 2.5 to 250 W/mK).