Integration of Wet Cleaning in 45 nm Pitch BEOL Processing

摘要

A partial-trench via first with self-aligned double patterning (SADP) approach is used to realize a 45 nm pitch using a dual damascene compatible hardmask. This back-end of line (BEOL) integration approach is used to investigate the ability to integrate advanced low-k materials and more specifically to assess their patterning performance. Throughout this SADP integration approach, different specific cleaning steps are required. A first cleaning process is needed after spacer etch and amorphous-carbon (a-C) strip to remove the spacer etch residues that are formed. Further in the integration flow, a TiN clean is needed together with a post-etch residue removal (PERR) after low-k etch.