A device including a first layer of first transistors interconnected by at least one first interconnection layer, where the first interconnection layer includes copper or aluminum, a second layer including second transistors, the second layer overlaying the first interconnection layer, where the second layer is less than about 2 micron thick, where the second layer has a coefficient of thermal expansion; and a connection path connecting at least one of the second transistors to the first interconnection layer, where the connection path includes at least one through-layer via, where the at least one through-layer via is formed through and in direct contact with a source or drain of at least one of the second transistors.