Finite Element Parametric Analysis on Fine-Pitch BGA (FBGA) Packages

Reduction in size of portable products such as cellular phones and camcorders has led to the miniaturization of integrated circuit packages. Fine-pitch BGA (FBGA) packages has been gaining its popularity due to compact in size and relatively low costing. With further down-sizing in package height, reliability issues like die cracking and warpage have surfaced as potential failures. Die cracks results in malfunction of an IC package, while the latter causes difficulty in board surface mounting. In this study, effects of package height on the die stress and warpage have been assessed by FEA. With overmold height ranging from 0.4∼0.6mm and substrate from 0.16∼0.32mm thick, the Overall Package Thickness coding from “T” (1.00<A< = 1.20mm) to “W” (0.65<A< = 0.80mm) are being analyzed. Results revealed that die stress and warpage decreases with increase in overmold thickness. However, an increment in the substrate thickness constituted to a rise in die stress and warpage. It was found that “top clearance” (distance between active die side and package top) of the package contributed to different trends in die stresses. Trends of results in varying the package and die sizes are also being investigated. The findings have provided guidelines for in-house designers in containing possible failures in FBGA packages.