Patent ID: 7303993
Filing Date: 2007-12-04
Classification: C09G,H01L

Abstract:
1. A method for polishing of a semiconductor wafer, the semiconductor wafer having copper interconnect metal and residual copper, comprising the steps of: contacting the wafer with a polishing composition, the polishing composition comprising oxidizer, inhibitor for the copper interconnect metal, complexing agent for copper, 0 to 3% by weight abrasive particle, 0.01 to 3% by weight modified cellulose, the modified cellulose having carboxylic acid functionality, 0.01 to 5% by weight copolymer blends of a first and a second copolymer each being formed from acrylic acid and methacrylic acid, the first copolymer being different from the second copolymer and balance water, wherein the copolymer blends of acrylic acid and methacrylic acid have a monomer ratio (acrylic acid/methacrylic acid) in the range of 1:30 to 30:1 and the copolymers have a molecular weight in the range of 1K to 1000K, and polishing the wafer with a polishing pad and the molecular weight of the first copolymer is different than the second copolymer; and clearing residual copper from the wafer with a polishing pad, wherein a weight percent ratio of the first copolymer to the second copolymer adjusts dishing and clearing of the copper interconnect metal, and further wherein a clearing time for clearing residual copper from the wafer is less than 30 seconds.