Embodiments include semiconductor packages and a method to form such semiconductor packages. A semiconductor package includes a plurality of dies on a substrate, and an encapsulation layer over the substrate. The encapsulation layer surrounds the dies. The semiconductor package also includes a plurality of dummy silicon regions on the substrate. The dummy silicon regions surround the dies and encapsulation layer. The plurality of dummy silicon regions are positioned on two or more edges of the substrate. The dummy silicon regions have a top surface substantially coplanar to a top surface of the dies. The dummy silicon regions include materials that include silicon, metals, or highly-thermal conductive materials. The materials have a thermal conductivity of approximately 120 W/mK or greater, or is equal to or greater than the thermal conductivity of silicon. An underfill layer surrounds the substrate and the dies, where the encapsulation layer surrounds portions of the underfill layer.