Patent ID: 7803203

Claim:
A method of chemical-mechanical polishing comprising: (i) providing a substrate having at least two metals; (ii) providing a polishing composition comprising: (a) an abrasive, (b) a first metal polishing rate modifier agent having a standard reduction potential less than 0.34 V relative to a standard hydrogen electrode, wherein the first metal polishing rate modifier agent is a quinine an anthraquinone selected from the group consisting of 9,10-anthraquinone-1,8-disulfonic acid, 9,10-anthraquinone-1,5-disulfonic acid, 9, 10-anthraquinone-2, 6-disulfonic acid, and salts thereof, (c) a second metal polishing rate modifier agent having a standard reduction potential greater than 0.34 V relative to a standard hydrogen electrode, and (d) a liquid carrier; (iii) contacting the substrate with a polishing pad and the polishing composition; (iv) moving the substrate relative to the polishing pad and the polishing composition; and (v) abrading at least a portion of the substrate to polish the substrate.