The interest in FOWLP as new flexible packaging technology platform is continuously increasing. High volume capability is proven for configurations with single die (WLFO), multi-die side-by-side, partially with discrete passives integration (WLMCM and WLSiP), both with single sided single and multiple RDL layers. The next step to achieve higher integration density, e.g. for mobile and IoT applications, is to go in the third dimension (WL3D/WLPoP) with total package thickness below 1mm, targeting 0.8mm and even less in the next development step. High design flexibility, superior performance and small form-factor in x and y, but even more important in z-dimension, are the essential packaging characteristics required for this type of smart system integration. The eWLB based WLFO technology platform of NANIUM promises to deliver all of those requirements. While previous generations of WLFO packages only consisted of one plane of single or multiple RDL layers (frontside RDL at BGA side), recent evolutions enable Package-on-Package (PoP) stacking of discrete passives too large to be embedded in the WLSiP, FlipChip, BGA or even another WLSiP on top of a thin bottom WLSiP, enabled by a second plane of single or multiple RDL layers (backside RDL) connected to the frontside RDL by TPV (thru package vias). This is allowing 3D integration on molded reconstituted round panel, resulting in so called WL3D/WLPoP solutions. For TPV processing and even more important to achieve the required total package thickness, WLSiP round recon panels need to be thinned below a thickness that allows self-supported handling of the panel anymore. Arising bow and warp triggers the demand for a temporary carrier solution to enable high backside processing yields at lowest total package thickness. The main challenge is the very high and non-linear thermal expansion of molded panels that needs to be combined with a temporary carrier solution. In this joint paper a study of different temporary carrier solutions, investigating different temporary bonding adhesive classes as well as carrier wafers with different thermal expansion properties will be discussed. The suitability of the carrier systems along the WLSiP panel backside thin-film RDL processing will be evaluated at identified critical process steps. Technology development test vehicles and first products using the newly developed technology will be presented including first reliability and manufacturability test results.