3D Power module with embedded WLCSP

The qualifications of a 2×3 and a 7×7 embedded WLCSP power module were shared in this paper. The 2×3 module was built on a switching voltage regulator with three passive components and one embedded WLCSP (2×3 at 0.4 mm pitch). The chip to module size ratio is 18.1 percent. The 7×7 module was built on a 7×7, 0.4 mm pitch WLCSP daisy chain test chip and five passive components. The silicon to module size ratio is 52.4 percent. Both 2×3 modules and 7×7 modules were subjected to drop test and temperature cycling test (TMCL). In addition, functional 2×3 modules underwent more device level reliability tests, such as dynamic optional life (DOPL), temperature humidity bias test (THBT), high temperature storage life (HTSL) and TMCL, etc. Solid chip to module, passives to module interconnect reliability was demonstrated alongside the robust module board level reliabilities. With adoption of PCB build up technology, the embedded WLCSP module offers 3D packaging options that are readily available to customers who demand full functionality in a small package and an attractive cost. Compared to other 3D packaging options, routing flexibility and robust interconnect reliability of the embedded module are distinguishing benefits. More designs taking advantages of this packaging technology are expected in the coming years.