Dry etching of copper film with hexafluoroacetylacetone via oxidation process

Dry etching of Cu film was achieved via oxidation process using oxidizing agents such as O2 plasma, O3, or O3 plasma, followed by the removal process of the copper oxides (CuOx) by reaction with hexafluoroacetylacetone [H(hfac)] to form volatile copper compound, [bis-hexafluoroacetylacetonate: Cu(hfac)2] and H2O. The etching rate was increased with the increase of etchant [H(hfac) and O3] flow rate, plasma power, and substrate temperature. Oxygen radical concentration is the highest in the plasma generated with ozone, which leads to the highest etching rate up to 1400 Å/min. The etch rate dependence on the substrate temperature showed the activation energy of about 7 kcal/mol and gas phase transport seems to be the rate controlling step.