Stacked BGA design, development, and materials selection considerations for improved testing and stacking, reduced warpage and environmental stress, and enhanced thermal qualities

Abstract

A stackable ball grid array (BGA) or fine-pitch ball grid array (FBGA) semiconductor package is particularly suitable for board-on-chip or chip-on-board applications in which a low-profile BGA or FBGA semiconductor package is needed. It enables the doubling of a memory module's capacity by stacking an additional device on top of the original device. However, due to the high tooling costs of dedicated BGA/FBGA semiconductor package test kits and burn-in boards, many memory suppliers only pursue a stacked TSOP solution that requires no new tooling during the assembly and testing of the TSOP singles. This paper discusses the various considerations and approaches of designing a stackable BGA or FBGA semiconductor package capable of being burned in and tested using a more efficient and cost-effective method than previously available for BGA and FBGA packages.