Patent ID: 8491808

Claim:
A method for chemical mechanical polishing of a substrate, comprising: providing a substrate, wherein the substrate comprises polysilicon, silicon oxide and silicon nitride; providing a chemical mechanical polishing composition, consisting of, as initial components: water; an abrasive; an alkyl aryl polyether sulfonate compound, wherein the alkyl aryl polyether sulfonate compound has a formula wherein R is a branched C 6-10 alkyl group; x is 2 to 8; and, M is selected from the group consisting of H, Na, K, Li and NH 4 ; a substance according to formula I wherein each of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 is a bridging group having a formula —(CH 2 ) n —, wherein n is an integer selected from 1 to 10; and, optionally, a pH adjusting agent, wherein the pH adjusting agent is an inorganic acid; providing a chemical mechanical polishing pad with a polishing surface; moving the polishing surface relative to the substrate; dispensing the chemical mechanical polishing composition onto the polishing surface; and, abrading at least a portion of the substrate to polish the substrate; wherein at least some of the polysilicon is removed from the substrate; wherein at least some of the silicon oxide and silicon nitride is removed from the substrate; wherein the alkyl aryl polyether sulfonate compound suppresses the removal rate of polysilicon.