Patent ID: 8553420

Claim:
A microelectronic assembly comprising: a dielectric element having oppositely-facing first and second surfaces and one or more apertures extending between the surfaces, the dielectric element further having conductive elements thereon; a first microelectronic element having a rear surface and a front surface facing the first surface of the dielectric element, the first microelectronic element having a first edge and a plurality of contacts exposed at the front surface thereof; a second microelectronic element overlying the first microelectronic element, the second microelectronic element having a rear surface and a front surface facing the rear surface of the first microelectronic element, a projecting portion of the front surface of the second microelectronic element extending beyond the first edge of the first microelectronic element, the projecting portion being spaced from the first surface of the dielectric element, the second microelectronic element having a plurality of contacts exposed at the projecting portion of the front surface; leads extending from contacts of the microelectronic elements through the at least one aperture to at least some of the conductive elements; and a heat spreader thermally coupled to at least one of the first microelectronic element or the second microelectronic element, wherein the heat spreader includes a first portion positioned over the rear surface of the first microelectronic element, a second portion positioned over the rear surface of the second microelectronic element, and a step between the first and second portions.