By using a patterned sacrificial layer for forming highly conductive metal regions, the formation of a reliable conductive barrier layer may be accomplished prior to the actual deposition of a low-k dielectric material. Hence, even highly porous dielectrics may be used in combination with highly conductive metals, substantially without compromising the diffusion characteristics and the electromigration performance. Hence, metallization layers for highly scaled semiconductor devices having critical dimensions of 50 nm and significantly less may be provided.