In mobile application, the WLP technology has been developing to make whole package size almost same as chip size. However, the I/O per chip unit area has increased so that it gets difficult to realize ideal pad pitch for better reliability. Recently, to achieve the thin and small size, high performance and low cost semiconductor package, Embedding Die and Fanout Technologies have been suggested and developed based on wafer level processing. In this work, as a solution of system in package, wafer level embedded package and fanout technology will be reviewed.
Firstly, Wafer level embedded System in Package (WL-eSiP) which has daughter chip (small chip) embedded inside mother chip (bigger chip) without any special substrate has been suggested and developed. To realize wafer level embedded system in package (WL-eSiP), wafer level based new processes like wafer level molding for underfilling and encapsulation by molding compound without any special substrate have been applied and developed, including high aspect ratio Cu bumping, mold thinning and chip-to-wafer flipchip bonding. Secondly, Fan-out Package is considered as alternative package structure which means merged package structure of WLCSP (wafer level chip size package) and PCB process. We can make IC packaging widen area for SIP(System in Package) or 3D package.
In addition, TSV and IPD are key enabling technology to meet market demands because TSV interconnection can provide wider bandwidth and high transmission speed due to vertical one compared to wire bonding technology and IPD can provide higher performance, more area saving to be assembled and small form factor compared to discrete passive components.
