An apparatus relates generally to a three-dimensional stacked integrated circuit. In such an apparatus, the three-dimensional stacked integrated circuit has at least a first die and a second die interconnected to one another using die-to-die interconnects. A substrate of the first die has at least one thermal via structure extending from a lower surface of the substrate toward a well of the substrate without extending to the well and without extending through the substrate. A first end of the at least one thermal via structure is at least sufficiently proximate to the well of the substrate for conduction of heat away therefrom. The substrate has at least one through substrate via structure extending from the lower surface of the substrate to an upper surface of the substrate. A second end of the at least one thermal via structure is coupled to at least one through die via structure of the second die for thermal conductivity.