Semiconductor packages including passive support wafers, and methods of fabricating such semiconductor packages, are described. In an example, a semiconductor package includes a passive support wafer mounted on several active dies. The active dies may be attached to an active die wafer, and the passive support wafer may include a monolithic form to stabilize the active dies and active die wafer during processing and use. Furthermore, the passive support wafer may include a monolith of non-polymeric material to transfer and uniformly distribute heat generated by the active dies.