Vol.4 No.7 (July 2014)
An Investigation of the Solder Ball Reliability for a Thermally Enhanced FC-PBGA Assembly
In this paper, the thermally enhanced FC-PBGA (Flip-Chip Plastic Ball Grid Array) assembly is a basic FC-PBGA package that is over-molded with molding compound, after which an aluminum heat spreader is adhered to the top of the molding compound and subsequently mounted on a PCB (Printed Circuit Board). Three-dimensional finite element analysis using the commercial ANSYS software is performed to study solder ball fatigue life for this thermally enhanced FC-PBGA as-sembly subjected to temperature cycling. In the simulation, all the solder bumps and the solder balls are modeled with nonlinear viscoplastic time and temperature dependent material properties based on Anand’s constitutive equation. Solder ball fatigue life is estimated by the widely accepted modified Coffin-Manson equation. The thermo-mechanical behavior of the assembly is pre- sented. Effects of alternative design parameters of the package components on solder ball fatigue life are analyzed. It is found that higher CTE of the substrate core, higher Young’s modulus of the substrate core, thicker substrate core, lower heat spreader CTE, lower heat spreader Young’s modulus, reduction of the thickness or width of the heat spreader, higher CTE of the molding compound and lower Young’s modulus of the molding compound result in better solder bump fatigue life. The effects of the parameters of the adhesive are found to have lesser impact on package reliability. However, lower CTE, lower Young’s modulus and greater thickness are found preferable.
林家帆 , 吴俊煌 , 朱圣浩 (2014) 散热强化型覆晶球栅数组组合体之锡球可靠度研究。 应用物理， 4， 141-154. doi: 10.12677/APP.2014.47017
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