Improved cleaning process for etch residue removal in an advanced copper / low-k device without the use of DMAC (dimethylacetamide)

摘要

The current residue remover used to remove the polymer residue developed after the plasma dry etching process contains DMAC, a toxic solvent. A new residue remover containing no DMAC was needed and a new DMAC-free formulation was therefore evaluated. Property tests of various films were conducted. E/R and roughness measurements showed little difference before and after treatment with the DMAC-free product. For the TV process, after opening the pad, the DMAC-free residue remover was applied and results confirmed the removal of polymer residue and the development of some corrosion. However, when compared to our usual results, there was less corrosion with the new residue remover. For the trench process, the test was conducted at a customer site which was equipped with single wafer cleaning tools. To compare the DMAC-free residue remover with the current DMAC utilizing POR, CD and DM results were examined. The result of that comparison shows little difference. On the other hand, capacitance density and breakdown voltage tests suggest that the use of the DMAC-free residue remover result in reliability improvements for passive devices such as MIM capacitors.