Semiconductor devices and manufacturing methods are provided for using a Recon interposer that provides a high density interface between the active semiconductor die and the semiconductor substrate and also provides the pitch fan-out. For example, a circuit assembly includes a silicon pad layer including a plurality of metal pads, each metal pad configured to receive a corresponding bump of a plurality of bumps. The circuit assembly further includes an oxide layer disposed on the silicon pad layer and an interposer dielectric layer disposed on the oxide layer. The interposer dielectric layer includes a plurality of routing traces that connect a top surface of the redistribution layer to a bottom surface of the interposer dielectric layer. The circuit assembly further includes an integrated circuit (IC) die attached to the plurality of routing traces at the top surface of the interposer dielectric layer using a plurality of IC bumps and an encapsulating material encapsulating at least a portion of the silicon pad layer, the oxide layer, the interposer dielectric layer, and the IC die to provide structural support for the circuit assembly.