An integrated circuit assembly may be formed having a substrate core, wherein the substrate core includes at least one heat transfer fluid channel formed therein, a first build-up layer formed on a first surface of the substrate core, and a second build-up layer formed on a second surface of the substrate core, and methods of fabricating the same. In embodiments of the present description, the integrated circuit structure may include at least one integrated circuit device formed within at least one of the first build-up layer and the second build-up layer. The embodiments of the present description allow for cooling within the substrate, which may significantly reduce thermal damage to the components of the substrate and/or integrated circuit devices within the substrate.