RMG Patterning by Digital Wet Etching of Polycrystalline Metal Films

A self-limiting wet etching of metal thin films has been developed for the replacement metal gate patterning in advanced logic devices, which will have aggressively scaled gate length and fin pitches. A uniform and highly selective wet etching of polycrystalline TiN films is demonstrated by a diffusion-limiting oxide growth on the metal surfaces as well as a subsequent highly selective oxide removal.