Encapsulation challenges for wafer level packaging

The interest of user for WLP has been raised because of benefits such as reduced package thickness, fan-out capability, high I/O, substrate-less process, integration of passives into structure, good thermal and electrical performance. The objective of this paper is to delineate technical challenges and issues that potential adopter of wafer level molding will face, technological solution availability and the broad application of WLP using granulated epoxy and liquid encapsulant such as epoxy, hybrid of epoxy-silicone, silicone. Result base on actual molding trial indicates among the different form of wafer level molding the challenges being faced are similar, including co-planarity, warpage, die shifting, coefficient of thermal expansion matching, incomplete filling, MBF and voiding.