DAMASCENE PROCESS FOR ALIGNING AND BONDING THROUGH-SILICON-VIA BASED 3D INTEGRATED CIRCUIT STACKS

摘要

Through-silicon-via (TSV) based 3D integrated circuit (3D IC) stacks are aligned, bonded and electrically interconnected using a transparent alignment material in the TSVs until the wafers are bonded. Embodiments include providing a first wafer having a first device layer and at least one first TSV filled with a conductive material, providing a second wafer having a second device layer, forming at least one second TSV in the second wafer, filling each second TSV with an alignment material, thinning the second wafer until the transparent material extends all the way through the wafer, aligning the first and second wafers, bonding the first and second wafers, removing the alignment material from the second wafer, and filling each second TSV in the second wafer with a conductive material.