A robust 45 nm-node, dual damascene interconnects with high quality cu/barrier interface by a novel oxygen absorption process

By a novel oxygen absorption process, low oxygen-content Cu-alloy is implemented for fully-scaled-down, 45 nm-node dual damascene interconnects (DDIs) with 140 nm-pitched lines and 70 nmOslash-vias. In this process, a very thin metal film as an oxygen absorber, which has larger negative change in the standard Gibbs free energy of oxidation than a barrier metal, is put on a natural oxide at a surface of electro-plated, Cu film. The oxygen atoms diffuse to the oxygen absorber, not to the barrier metal under the Cu film, achieving high quality Cu/barrier interface after annealing. Combining the oxygen absorption process with Cu-alloy process, 45 nm-node DDI in molecular-pore-stacking (MPS) SiOCH film is successfully obtained with high endurances for SIV, EM and TDDB