Thermal Strategy for Modeling the Wirebonded Pbga Packages

Abstract

The Plastic Ball Grid Array (PBGA) package attracts considerable interest, being one of the most promising packaging technologies of the moment. Thermal analysis of a package and a Printed Circuit Board (PCB) stack-up is performed for a better understanding of package constitutive elements, allowing an enhanced thermal coupling of package and board for cost effective thermal management. A commercial Computational Fluid Dynamics (CFD) software was applied for thermal simulation. The study focuses on detailed thermal modeling of a 256 Wirebonded PBGA (depopulated bump array) package in a natural convection setup. The model was refined to include all the features, and the calculated junction-toambient thermal resistance for each simulation was compared to available experimental data. The order of creating the internal structures in the model has a strong impact on the package thermal characteristics. The calculated errors varied from 5% (detailed model) to 43% (simplified model).

Effect of both PCB thermal conductivity and nature of forced convection environment on component operating temperature: Experimental measurement and numerical prediction

“…The PCB modelling methodology applied followed three different strategies defined in Figure 10. Recognised modelling strategies for high conductivity multi-layer PCBs include detailed models as shown in Figure 10(a) [30], anisotropic representations as shown in Figure 5(b) [20,25,31] or using isotropic values [31]. However, a fourth option was also investigated and it is presented in Figure 10(c).…”