"Universal" barrier cmp slurry for use with low dielectric constant interlayer dielectrics

During processing of a semiconductor wafer bearing a structure including a low-k dielectric layer, a cap layer and the metal-diffusion barrier layer, a chemical mechanical polishing method applied to remove the metal-diffusion barrier material involves two phases. In the second phase of the barrier-CMP method, when the polishing interface is close to the low-k dielectric material, the polishing conditions are changed so as to be highly selective, producing a negligible removal rate of the low-k dielectric material. The polishing conditions can be changed in a number of ways including: changing parameters of the composition of the barrier slurry composition, and mixing an additive into the barrier slurry.