Step Coverage Quality of Cu Films by Supercritical Fluid Deposition Compared with Chemical Vapor Deposition

Abstract

Feasibility of step coverage (SC) by supercritical fluid deposition (SCFD) of Cu was evaluated using a finite element method (FEM) simulation with experimentally estimated kinetics and transport properties of the precursor. This SC by Cu-SCFD was compared with that by chemical vapor deposition (CVD). SCFD showed superior SC, especially for ultra narrow features less than 1 µm wide, although CVD has a higher diffusion coefficient. This superior SC was due to the non-linear reaction kinetics of SCFD (CVD has linear reaction kinetics), where precursor concentration had negligible effect on growth rate when the precursor concentration was higher than about 1 mol/L.