slurry 26 is dispensed onto the polishing pad 13 through a separate slurry dispensing nozzle 20 accordingly the polishing pad 13 rotates the composition solution 24 dispensed thereon into contact with the copper layer 19 on the substrate 17 as the substrate holder 14 rotates the copper layer 19 against the polishing pad 13 simultaneously the copper layer 19 is polished by the polishing slurry 26 dispensed separately onto the polishing pad 13 as the composition solution 24 contacts the copper layer 19 metal ions in the solution 24 are spontaneously reduced to displacement metal atoms and copper atoms in the copper layer 19 are simultaneously oxidized to copper cations consequently the reduced displacement metal atoms spontaneously replace the oxidized copper atoms in the copper layer 19 such that the atomic percentage of copper atoms is decreased and the atomic percentage of displacement metal is correspondingly increased in the copper layer 19 as a result the copper layer 19 is rendered substantially resistant to copper oxide formation prior to resumption of semiconductor fabrication processing as indicated in step s 4 in fig3 the oxidized copper ions displaced from the copper layer are carried away in the composition solution it will be appreciated by those skilled in the art that the substantially oxidation resistant quality of the treated copper layer 19 permits the q time between chemical mechanical planarization of the copper layer 19 and subsequent deposition of an etch stop layer not shown for example onto the copper layer 19 for higher order fabrication of metal lines and vias to be substantially.