Abrasives for chemical mechanical polishing

A slurry, comprising:

• an oxidizer;
• a corrosion inhibitor;
• a buffer system;
• and
• an abrasive;
• wherein the slurry is characterized by providing a high Cu polish rate, a low Cu etch rate, and a high-selectivity to a Cu diffusion barrier when used for chemical mechanical polishing.

A slurry, comprising:

• an oxidizer;
• a corrosion inhibitor;
• a buffer system;
• and an abrasive;
• wherein the abrasive is harder than a Cu diffusion barrier, and less hard than a dielectric material.

A slurry, comprising:

• an oxidizer;
• a corrosion inhibitor;
• a buffer system;
• and an abrasive;
• wherein the abrasive is harder than Cu, and less hard than a Cu diffusion barrier, and less hard than a dielectric material.

A method of forming a damascene structure, comprising:

• forming trenches in an insulating layer disposed on a substrate, the trenches having a bottom surface and side surfaces;
• forming a barrier layer over a top surface of the insulating layer and over the bottom and side surfaces, the barrier layer having a first hardness;
• forming a layer of metal over the barrier layer;
• and
• removing the metal layer from over the that portion of the barrier layer that overlies the top surface of the insulating layer;
• wherein removing the metal layer comprises polishing the metal with a slurry having an abrasive that is harder than the metal and less hard than the barrier layer.

A slurry for polishing copper overlying a barrier layer, comprising:

• water;
• hydrogen peroxide;
• a corrosion inhibitor;
• a pH buffer;
• and
• an abrasive;
• wherein the abrasive has a hardness between hardness of copper and a hardness of the barrier layer.