Copper is a desirable material to replace aluminum-based alloys in the metallization of very large-scale integrated circuits, due to its high conductivity and reduced electromigration. However, practical ways to grow high quality copper layers on top of the common materials used as barrier layers on silicon is problematic, because of several issues, like poor adhesion and reduced coverage of high aspect-ratio surface features. We will describe efforts in developing procedures and chemical compounds for the growth of high quality films of copper on barrier layers. Our work is based on ab-initio calculations of the energetics and dynamics of the growth processes involved, including the interaction of the chemicals with the surfaces. The calculations presented use density functional theory, and in particular the SIESTA code.