Abstract: An advanced back-end-of-line (BEOL) integration scheme for semiconductor devices using very low-k dielectric materials is disclosed. The disclosed method for forming a metal interconnect structure in a semiconductor integrated circuit device comprises forming the metal interconnects using a through-mask plating (TMP) process, and encapsulating the interconnects with a barrier layer by selectively depositing a barrier layer material using an electroless liner plating process or by non-selectively depositing a blanket insulator diffusion barrier layer using PVD or CVD techniques.