Wafer-on-Wafer (WOW) is a 3D integration technology developed by the the WOW Alliance, Japan.

WOW Alliance

The WOW 3D integration approach uses wafer bonding (adhesive bonding), wafer thinning, and post-bonding TSVs (through the thin Si and adhesive layers) technologies. [1]

WOW stack.png
Cross-sectional SEM pictures of a) WOW stack and b) ultra-thin DRAM wafer, respectively.[1]


See also TSMC's WoW (Wafer-on-Wafer).


  1. 1.0 1.1 T. Ohba, “Production-worthy WOW 3D integration technology using bumpless interconnects and ultra-thinning processes,” in 2016 IEEE Symposium on VLSI Technology, 2016, pp. 1–2. Available: