Compositions and methods for controlled polishing of copper
The present invention provides an aqueous composition useful for polishing copper on a semiconductor wafer comprising by weight percent 0.001 to 6 inhibitor for a nonferrous metal, 0.05 to 10 complexing agent for the metal, 0.01 to 25 copper removal agent for accelerating the removal of the copper, 0.5 to 40 abrasive, 0 to 10 selected from the group comprising, polyvinylpyrrolidone, thermoplastic polymer and mixtures thereof, wherein the copper removal agent is imidazole.
1 . An aqueous composition useful for polishing copper on a semiconductor wafer comprising by weight percent 0.001 to 6 inhibitor for a nonferrous metal, 0.05 to 10 complexing agent for the metal, 0.01 to 25 copper removal agent for accelerating the removal of the copper, 0.5 to 40 abrasive, 0 to 10 selected from the group comprising, polyvinylpyrrolidone, thermoplastic polymer and mixtures thereof, wherein the copper removal agent is imidazole.
2 . The composition of claim 1 wherein the imidazole is a compound of a formula selected from the group comprising:
wherein, R 1 and R 2 are selected from the group comprising a hydrogen atom, an alkyl group optionally having substituent(s), an unsaturated alkyl group optionally having substituent(s), a cycloalkyl group optionally having substituent(s), an aralkyl group optionally having substituent(s), an arylalkenyl group optionally having substituent(s), an aryl-cyclic hydrocarbon group optionally having substituent(s), an aryl group optionally having substituent(s), a heterocyclic residue optionally having substituent(s) and an alkoxycarbonyl group optionally having substituent(s) and combinations thereof.
3 . The composition of claim 1 wherein a ratio of the weight percent of the imidazole to the inhibitor is at least 3 to 1.
4 . The composition of claim 1 wherein the weight percent of the imidazole is 0.01 to 5.
5 . The composition of claim 1 wherein the inhibitor is benzotriazole.
6 . The composition of claim 1 wherein the thermoplastic polymer is polyvinyl alcohol.
7 . The composition of claim 1 wherein the aqueous composition has a pH of 7.5 to 10.
8 . An aqueous composition useful for polishing copper on a semiconductor wafer comprising by weight percent 0.001 to 6 benzotriazole to inhibit corrosion of the copper, 0.05 to 10 complexing agent for the copper, 0.01 to 25 imidazole for accelerating the polishing of the copper, 0.5 to 40 abrasive, 0 to 10 oxidizer and 0 to 10 selected from the group comprising, polyvinylpyrrolidone, polyvinyl alcohol and mixtures thereof and balance water, wherein a weight percent ratio of the imidazole to the benzotriazole is at least 3 to 1.
9 . A method for polishing copper from a semiconductor wafer comprising:
contacting the wafer with a polishing composition, the wafer containing the copper, the polishing composition comprising by weight percent 0.001 to 6 inhibitor for a nonferrous metal, 0.05 to 10 complexing agent for the metal, 0.01 to 25 imidazole, 0.5 to 40 abrasive, 0 to 10 oxidizer, 0 to 10 selected from the group comprising, polyvinylpyrrolidone, polyvinyl alcohol and mixtures thereof and balance water; and
polishing the wafer with a polishing pad, wherein the imidazole accelerates the polishing of the copper.
10 . The method of claim 9 wherein the imidazole is a compound of a formula selected from the group comprising:
wherein, R 1 and R 2 are selected from the group comprising a hydrogen atom, an alkyl group optionally having substituent(s), an unsaturated alkyl group optionally having substituent(s), a cycloalkyl group optionally having substituent(s), an aralkyl group optionally having substituent(s), an arylalkenyl group optionally having substituent(s), an aryl-cyclic hydrocarbon group optionally having substituent(s), an aryl group optionally having substituent(s), a heterocyclic residue optionally having substituent(s) and an alkoxycarbonyl group optionally having substituent(s) and combinations thereof.