In sophisticated semiconductor devices, densely packed metal line layers may be formed on the basis of an ultra low-k dielectric material, wherein corresponding modified portions of increased dielectric constant may be removed in the presence of the metal lines, for instance, by means of a selective wet chemical etch process. Consequently, the metal lines may be provided with desired critical dimensions without having to take into consideration a change of the critical dimensions upon removing the modified material portion, as is the case in conventional strategies.