Integration of Through-Dielectric-Via on Buried Power Rail and Slit Nano Through-Silicon-Via for Enhanced Backside Connectivity

Backside power delivery network (BSPDN) is a promising technology that continues the standard cell scaling. Based on the frontside (FS) patterned buried power rail (BPR) and self-aligned slit nano through-silicon-via (nTSV) scheme, we further integrate a through dielectric via (TDV) on top, offering additional routing flexibility and demonstrating the full connections between BS and FS metal lines through nTSV, BPR and TDV. TDV is patterned after BPR recess etching and dielectric refilling. The connection between TDV and BPR is confirmed using TEM. Both TiN/W and Molybdenum (Mo) are used for TDV filling. The extracted TDV resistance shows that Mo is preferred over TiN/W counterparts for small-dimension structures.