3D large scale integration technology using Wafer-on-Wafer (WOW) stacking

Wafer-scale three-dimensional (3D) technologies, so-called Wafer-on-Wafer (WOW), beyond post-scaling for high-density integration are discussed. WOW module technologies consisting of wafer thinning, stacking, TSV (Through-Silicon-Via) interconnects, and packaging are described. No degradation for advanced 35-nm SRAM logic and FRAM devices was observed with ultra-thinning below 10-μm for 300-mm and 200-mm wafers. Production-worthy die yield due to wafer stacking and a comparison of critical scaling for future manufacturability are presented.