Inorganic ARC for 0.18pm and Sub-O.18p.m Multilevel Metal Interconnects

The accelerated control of critical dimensions (CD) at sub-0.25pm region for semiconductor manufacturing has increased worldwide interests in anti-reflective coating (ARC) process. In this paper, we report on a novel designed inorganic ARC for deep-UV lithography and implementation of the ARC into multilevel metal interconnects for 0.18pm and sub-0.18pm technologies. The designed Si,O,N, ARC is not only reducing substrate reflectivity to a minimum and prevent DUV resist footing, but also serving as a hardmask for metal etch. Back-end-of-line (BEOL) sub0.25pm multilevel metal patterning and etch with Si,O,N, ARC produced excellent metal profiles and 100% electrical comb yields. The designed ARC has also shown superior results to conventional metal ARC TIN. The dielectric constant value is close to silicon oxide.