Chemical mechanical polishing method for cobalt

A method of chemical mechanical polishing cobalt, comprising:

• providing a substrate comprising cobalt and TiN;
• providing a chemical mechanical polishing composition, consisting of, as initial components:
• water;
• 0.1 wt % to 1 wt % of hydrogen peroxide;
• 0.3 wt % to 1 wt % aspartic acid or salts thereof;
• 0.3 wt % to 2 wt % of spherical colloidal silica abrasives having a negative zeta potential and an average particle diameter of 10 nm to 23 nm;
• and
• 0.005 wt % to 0.1 wt % adenine;
• optionally a biocide;
• optionally, a pH adjusting agent;
• optionally, a surfactant;
• optionally, adipic acid, salts thereof or mixtures thereof;
• a pH from 7.5 to 9;
• providing a chemical mechanical polishing pad, having a polishing surface;
• creating dynamic contact at an interface between the chemical mechanical polishing pad and the substrate;
• and
• dispensing the chemical mechanical polishing composition onto the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate to remove at least some of the cobalt.