Electronic device package technology is disclosed. In one example, an electronic device includes a plurality of dies (104) stacked on a substrate (102) and a reference die (106) on the plurality of dies and having a fiducial marker (108) that indicates a spatial position of the plurality of dies for alignment of an electronics assembly tool (110). The fiducial marker can comprise a physical alteration of the reference die, such as indicia that is sawed or laser/plasma/chemical etched. A transparent dielectric layer (120) is disposed on the reference die such that the tool can locate the fiducial marker in three dimensional space through the transparent layer. The dielectric layer is etched corresponding to a photomask after a photoresist is disposed on the dielectric layer. The etched dielectric layer comprises at least one redistribution layer (116) electrically coupled to the vertical wire interconnect structure (112) to provide an ultra-thin package. A method of aligning an electronics assembly tool is disclosed.