Bilayer HDP CVD/PE CVD cap in advance BEOL interconnect structures and method thereof

摘要

An advanced back-end-of-line (BEOL) metallization structure is disclosed. The structure includes a bilayer diffusion barrier or cap, where the first cap layer is formed of a dielectric material preferably deposited by a high density plasma chemical vapor deposition (HDP CVD) process, and the second cap layer is formed of a dielectric material preferably deposited by a plasma-enhanced chemical vapor deposition (PE CVD) process. A method for forming the BEOL metallization structure is also disclosed. The invention is particularly useful in interconnect structures comprising low-k dielectric material for the inter-layer dielectric (ILD) and copper for the conductors.