A chemical mechanical polishing (CMP) composition (Q) comprising: (A) cocoon-shaped silica particles, (B) a compound or salt of general formula (I) having at least one polymeric polyether chain: and wherein the indices and the variables have the following meaning: X is CH 2 N, CH 2 CH 2 N, CH 2 CH 2 CH 2 N, CH 2 CH 2 CH 2 CH 2 N, CH,CH 2 , CH 2 CH, CH 2 CH 2 CH, C=O or CH 2 CH 2 O wherein X is bonded by the carbon atom of the respective group to the nitrogen R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are independently from each other O - , H, OH, COO - , COONa, CH, CH 2 , CH 3 , CH 2 CH 3 , C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl with at least one carbon carbon double bond, C 1 -C 20 -alkyl-acyl, C 2 -C 20 -alkenyl-acyl, CH 2 CH 2 OH, OHCHCHOH, CH 2 COO - , CH 2 COONa, CH 2 CH 2 O or CH 2 CH(CH 3 )O, u is 1 t is 0 or 1, I, m, o, q and s are an integer within a range of from 0 to 500, n, p and r are an integer within a range of from 1 to 500, when X is CH 2 , C=O or CH 2 CH 2 O, then I and m are zero, and when X is CH 2 N, CH 2 CH 2 N, CH 2 CH 2 CH 2 N, CH 2 CH 2 CH 2 CH 2 N, CH, CH 2 CH, CH 2 CH 2 CH, then I is at least one,, and (C) an aqueous medium wherein the composition (Q) has a pH of from 2 to 6. (A) cocoon-shaped silica particles, (B) a compound or salt of general formula (I) having at least one polymeric polyether chain: and wherein the indices and the variables have the following meaning: X is CH 2 N, CH 2 CH 2 N, CH 2 CH 2 CH 2 N, CH 2 CH 2 CH 2 CH 2 N, CH,CH 2 , CH 2 CH, CH 2 CH 2 CH, C=O or CH 2 CH 2 O wherein X is bonded by the carbon atom of the respective group to the nitrogen R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are independently from each other O - , H, OH, COO - , COONa, CH, CH 2 , CH 3 , CH 2 CH 3 , C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl with at least one carbon carbon double bond, C 1 -C 20 -alkyl-acyl, C 2 -C 20 -alkenyl-acyl, CH 2 CH 2 OH, OHCHCHOH, CH 2 COO - , CH 2 COONa, CH 2 CH 2 O or CH 2 CH(CH 3 )O, u is 1 t is 0 or 1, I, m, o, q and s are an integer within a range of from 0 to 500, n, p and r are an integer within a range of from 1 to 500, when X is CH 2 , C=O or CH 2 CH 2 O, then I and m are zero, and when X is CH 2 N, CH 2 CH 2 N, CH 2 CH 2 CH 2 N, CH 2 CH 2 CH 2 CH 2 N, CH, CH 2 CH, CH 2 CH 2 CH, then I is at least one,, and X is CH 2 N, CH 2 CH 2 N, CH 2 CH 2 CH 2 N, CH 2 CH 2 CH 2 CH 2 N, CH,CH 2 , CH 2 CH, CH 2 CH 2 CH, C=O or CH 2 CH 2 O wherein X is bonded by the carbon atom of the respective group to the nitrogen R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and R 9 are independently from each other O - , H, OH, COO - , COONa, CH, CH 2 , CH 3 , CH 2 CH 3 , C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl with at least one carbon carbon double bond, C 1 -C 20 -alkyl-acyl, C 2 -C 20 -alkenyl-acyl, CH 2 CH 2 OH, OHCHCHOH, CH 2 COO - , CH 2 COONa, CH 2 CH 2 O or CH 2 CH(CH 3 )O, u is 1 t is 0 or 1, I, m, o, q and s are an integer within a range of from 0 to 500, n, p and r are an integer within a range of from 1 to 500, when X is CH 2 , C=O or CH 2 CH 2 O, then I and m are zero, and when X is CH 2 N, CH 2 CH 2 N, CH 2 CH 2 CH 2 N, CH 2 CH 2 CH 2 CH 2 N, CH, CH 2 CH, CH 2 CH 2 CH, then I is at least one,, and (C) an aqueous medium <EOS>