Patent ID: 8461672

Claim:
A method of fabricating a plurality of stacked microelectronic units, comprising: a) providing a plurality of subassemblies each being a reconstituted wafer or portion of a reconstituted wafer and each having a front side and a rear side remote from the front side, each subassembly including a plurality of spaced apart microelectronic elements each including a semiconductor chip, the microelectronic elements having front faces exposed at the front side, contacts exposed at the front side, rear faces adjacent to the rear side, and edges extending between the front and rear faces, each subassembly further including a fill layer overlying the rear faces of the microelectronic elements and extending between the edges of adjacent microelectronic elements; b) forming a plurality of traces at the front side of each subassembly, the traces extending from the contacts to beyond the edges of the microelectronic elements; c) reducing a thickness of a first one of the subassemblies from the rear side to reduce a thickness of the microelectronic elements therein; d) joining a second one of the subassemblies with the first subassembly such that the front side of the second subassembly confronts the rear side of the first subassembly and such that the front faces of microelectronic elements of the second subassembly confront the rear faces of the microelectronic elements of the first subassembly; e) forming leads in at least one opening extending downwardly from the rear side of the second subassembly, the leads connected to the traces of the microelectronic elements of the first and second subassemblies, the at least one opening having an inclined wall at an angle relative to a normal direction with respect to the plane defined by the front faces of the microelectronic elements; and f) severing the joined microelectronic assemblies along edges of the microelectronic elements into stacked microelectronic units, such that edge surfaces of the microelectronic units include an inclined wall of the at least one opening, each microelectronic unit including leads extending along the surface of the at least one inclined wall.