Copper seed layer for an interconnect structure having a doping concentration level gradient

摘要

A trench is opened in a dielectric layer. The trench is then lined with a barrier layer and a metal seed layer. The metal seed layer is non-uniformly doped and exhibits a vertical doping gradient varying as a function of trench depth. The lined trench is then filled with a metal fill material. A dielectric cap layer is then deposited over the metal filled trench. Dopant from the non-uniformly doped metal seed layer is then migrated to an interface between the metal filled trench and the dielectric cap layer to form a self-aligned metal cap.