Semiconductor assemblies with systems and methods for using an interchangeable interposer to connect die to common substrate

A semiconductor device assembly, comprising:

• a substrate having atop surface and a bottom surface, first and second layers of prepreg disposed between the top and bottom surfaces, the first layer of prepreg being disposed closer to the top surface than the second layer of prepreg, and a core layer disposed between the first and second layers of prepreg, the substrate further comprising a cavity extending from the top surface to an intermediate depth between the top surface and the bottom surface, the cavity having an intermediate surface vertically aligned with an interface between the first layer of prepreg and the core layer;
• a controller having a first pin-out pattern;
• and
• an interposer having a top surface with the first pin-out pattern that is directly attached to the controller and a bottom surface having a second pin-out pattern, the interposer interconnecting at least a portion of the first and second pin-out patterns,
• wherein the interposer is configured to be directly attached to the intermediate surface of the substrate in the cavity at the intermediate depth,
• wherein the interposer has a first length less than a second length of the cavity such that a gap extends between a side edge of the interposer and a facing sidewall of the cavity, and
• wherein the second pin-out pattern of the interposer is directly attached to corresponding electrical contacts on the intermediate surface of the substrate having the second pin-out pattern.