Removal of post-dry etch polymer residue from BEOL structures using an ozonated-DI-water technology

The formation of polymer residues on structural features after dry etching and resist ashing is a major problem for both BEOL processing. Problems associated with the oxidation reaction that occurs between the etch residue and the oxidizer gas in the plasma chamber during dry ashing creates residue that is difficult to remove in subsequent wet clean only. Sometimes the strippers are only successful removing etch residues in more than 180 seconds on the single wafer tools. The use of ozonated-DI-water will help to enhance the cleaning efficiency and then reduce the chemical cleaning time. This technology is successful in effectively removing the etch residues in 60 sec DIO₃ only after copper dual damascene post trench etch on the single wafer tool. A very thin oxide layer is formed on the copper surface instead of etching it. In addition to this application have also been successfully improve etch residues removal significantly by solely using DIO₃.