Embodiments of the invention include a method for electro chemical
mechanical polishing of a substrate. The process includes flowing an
electro chemical mechanical polishing (ECMP) slurry having a high
viscosity with a polishing agent over a portion of the substrate.
Electrical current is passed through the slurry and substrate. The
electrical current, in conjunction with the abrading action of the slurry
as it flows over the surface of the substrate, serves to remove at least
a portion of the metal layer from the substrate. The invention also
includes various slurry embodiments.