Patch on interposer architecture for low cost optical co-packaging

A semiconductor package comprises an interposer and a photonics die. The photonics die has a front side with an on-chip fiber connector and solder bumps, the photonics die over the interposer with the on-chip fiber connector and the solder bumps facing away from the interposer. A patch substrate is mounted on the interposer adjacent to the photonics die. A logic die is mounted on the patch substrate with an overhang past an edge of the patch substrate and the overhang is attached to the solder bumps of the photonics die. An integrated heat spreader (IHS) is over the logic die such that the photonics die does not directly contact the IHS.