Patent ID: 6127282
Filing Date: 2000-10-03
Classification: H01L

Abstract:
A method for removing copper residue ingrained into a top portion of an insulating layer on a semiconductor wafer, said insulating layer being exposed on said semiconductor wafer, the method including the steps of:A. immersing said semiconductor wafer in an acidic solution for a first time period, said acidic solution including:hydrogen fluoride (HF) having a concentration in said acidic solution in the range of from about 50 ml/l to about 500 ml/l; andhydrogen chloride (HCl) having a concentration in said acidic solution in the range of from about 1 ml/l to about 20 ml/l,said semiconductor wafer being immersed in said acidic solution to break bonds in said copper residue;B. preserving a substantial portion of said insulating layer exposed on said semiconductor wafer by etching a thin portion at the top of said insulating layer to loosen said copper residue ingrained into said top portion of said insulating layer with control of said first time period of immersing said semiconductor wafer in said acidic solution to be less than about 15 seconds during said step A;C. immersing said semiconductor wafer in a cleaning solution for a second time period, said cleaning solution including:tetramethylammonium hydroxide ((CH.sub.3).sub.4 NOH) having a concentration in said cleaning solution in the range of from about 5 g/l to about 100 g/l; andsurfactant (RE-610) having a concentration in said cleaning solution in the range of from about 0.01 g/l to about 0.10 g/l,said semiconductor wafer being immersed in said cleaning solution for removing copper residue having broken bonds after said step A from said semiconductor wafer; andD. preventing diffusion of copper from said copper residue into said insulating layer by substantially removing said copper residue loosened by said acidic solution from said top portion of said insulating layer while preserving a substantial portion of said insulating layer on said semiconductor wafer by controlling said second time period of immersing said semiconductor wafer in said cleaning solution in said step C to be at least 3 times greater than said first time period of immersing said semiconductor wafer in said acidic solution in said step A.