Papers by Author: David Lou

Abstract: 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.

Abstract: Beginning at the 45nm node, the semiconductor industry is moving to high-k gate dielectrics and metal gate electrodes for CMOS logic devices [. Although different approaches of building these devices are being pursued, most of the industry has consolidated behind a gate last approach, in which the transistor is built around a dummy poly polysilicon gate, which is subsequently removed and replaced with a metal gate. Current approaches to removing the dummy poly gate include plasma-based dry processes and liquid-phase wet etching.