Comparative Study on the Step Coverage Quality of Cu Film by SCFD and CVD

Abstract

Supercritical fluid deposition (SCFD) is a hybrid approach that combines the advantages of CVD and liquid-phase deposition. It usually employs supercritical CO2 (scCO2), which can dissolve various precursors and enables deposition at relatively high precursor concentrations. SCFD can provide conformal step coverage and superior gap-filling ability due to the high diffusivity and low viscosity of scCO2. In this paper, we will discuss the step coverage of Cu-SCFD comparing with that by Cu-CVD. Numerical simulation based on kinetic analyses on SCFD and CVD showed that SCFD may be a better choice to make conformal deposition onto high aspect ratio features with small dimension in nano-meter size. CVD may be a better choice for micro-meter scale features.