Abstract
Package on Package (PoP) is one of packing technology to implement in mobile application. PoP is a stacking technology to integrate two or more separated packages. Specifically for application processor or baseband die of smartphone and tablets, the design to stack AP/BB chip and memory package is adopted generally in iOS or Android phones. One of PoP structure, substrate base of high bandwidth PoP (HBW-PoP), is a mature packaging type and has accessed to market in recent years. Seeking to the alternative PoP technologies, the demand is to reduce package dimension to cram more chip functions and expand battery capacity by size as larger as possible. Fan out wafer level package (FOWLP) efficiently enable higher I/O counts for high performance edge computing by re-distribution organic layers (RDL). In addition, the more advanced silicon node, the higher cost design houses bear in packaging development. Therefore, this study is that we propose a fan out package on package (FO-PoP) with chip last process, which features have higher process yield, shorter cycle time benefits than chip first platform. Organic RDL can miniaturize package height by replacing substrate base PoP. The total height can reach less than 0.5mm and meet up the market trend in wearable and smartphone applications. Known-good-die (KGD) feature of chip last process extremely control RDL process yield to reduce AP dies loss and further improve overall packaging yield. Then, the in-parallel process between bottom RDL and die micro-bumping process can shorten cycle time for production efficiency. In this paper, test vehicle verification includes warpage in the criteria and reliability validation passed by packaging level reliability and board level reliability.
