Optimization of Cu/Low-k Dual Damascene Post-Etch Residue and TiN Hard Mask Removal

For advanced technology nodes TiN hard mask integration into Cu/low-k via/trench DD process requires the mask to be fully stripped after DD etching. The one-step H2O2 containing wet chemical clean aiming to removing TiN mask often failed to simultaneously clean etch residue. We developed more reliable two-step wet chemical process combining a solvent-based post-etch residue clean followed by a solvent/H2O2 mixture strip for TiN mask removal. Bath lifetime optimization was also demonstrated.