Abstract: Recessed semiconductor die stacks. In some embodiments, a semiconductor device includes a first die including an active side and a back side, the back side including a non-recessed portion thicker than a recessed portion, the recessed portion including one or more through-die vias on a recessed surface; and a second die located in the recessed portion, the second die including an active side facing the recessed surface of the first die and coupled thereto through the one or more through-die vias. In another embodiment, a method includes creating a recess on a first die having a first thickness, the recess having a depth smaller than the first thickness; coupling a second die having a second thickness greater than the depth to the recess; and reducing the thickness of the second die by an amount equal to or greater than a difference between the second thickness and the depth.