An innovative die to wafer 3D integration scheme: Die to wafer oxide or copper direct bonding with planarised oxide inter-die filling

An innovative die to wafer stacking is proposed for 3D devices. Known good dices are bonded on a processed wafer thanks to direct bonding. Oxide layers or patterned oxide/copper layers are used as the bonding medium. After a first thinning, a low stress high deposition rate oxide is deposited to embed the dices. A final thinning is then done to recover a flat and smooth surface before the trough silicon vias